OTB Spacecraft ODAR

0087-EX-CN-2018 Text Documents

General Atomics

2018-02-01ELS_204219

                      ORBITAL DEBRIS ASSESSMENT REPORT
                      (ODAR) FOR THE ORBITAL TEST BED (OTB)
                      SATELLITE

                      This document supports the General Atomics Electromagnetic
                      Systems (GA-EMS) Orbital Test Bed Satellite FCC license and has been
                      prepared in accordance with:
                      NASA Technical Standard NASA-STD-8719.14A (inc. change 1, 25-5-
                      2012) Process for Limiting Orbital Debris
                      DAS Software version used in analysis V 2.1.1




          Date: December 2017

Document No.: OTB-DOC-000638-05

                      General Atomics Electromagnetic Systems
                      345 Inverness Drive South, Suite 100
                      Englewood, CO 80112

                      Tel: 303.790.0653 | Fax: 303.792.2386




    DISTRIBUTION STATEMENT: Confidential and proprietary information of GA-EMS. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



APPROVALS

 Prepared by:             Clare Martin, Director Orbital Solutions                            Signed:

 Reviewed by:             Matt Yavorsky, Systems Engineer                                     Signed:          Matthew Yavorsky
 Approved by:             Will Thompson, Project Manager                                      Signed:



DOCUMENT REVISION STATUS

 Revision         Nature of Changes                                                                   Edited by                           Date
 Number
 01               Initial issue for comment.                                                          M Brown                             Aug ‘13
 02               Addition of Section 7A hazardous materials data.
                                                                                                      M Brown                             Aug ‘13
                  Updated spacecraft design information.
 03               Updated contacts in 1.1.2, updates to sections
                  1.1.4, 1.1.7, 2.1.9, 6.1.4, and 6.1.6, figures 2-1
                                                                                                      T Murphy                            Apr ‘15
                  and 2-2 updated, as well as minor grammatical
                  corrections throughout.
 04               Updated for inclusion of the drag augmentation
                  device, complete reformatting of the document                                       T Murphy                            Sept ‘17
                  and content.
 05               Updated for heritage of the drag augmentation
                  device. Updated following acquisition of SST-US by
                                                                                                      C Martin                            Dec ‘17
                  GA-EMS, including the OTB satellite and all
                  associated IP.




                                                                                                                                                                   i
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



Table of Contents
1     Applicable Documents .............................................................................................. 1
2     Acronyms and Abbreviations ....................................................................................... 1
3     PREAMBLE ............................................................................................................. 2
4     ODAR SELF ASSESSMENT ............................................................................................ 3
5     PROGRAM MANAGEMENT AND MISSION OVERVIEW ............................................................. 4
6     SPACECRAFT DESCRIPTION ......................................................................................... 6
7     ASSESSMENT OF SPACECRAFT DEBRIS RELEASED DURING NORMAL OPERATIONS ........................ 10
8     ASSESSMENT OF SPACECRAFT INTENTIONAL BREAKUPS AND POTENTIAL FOR EXPLOSIONS ........... 11
9     ASSESSMENT OF SPACECRAFT POTENTIAL FOR ON-ORBIT COLLISIONS .................................... 14
10 ASSESSMENT OF SPACECRAFT POSTMISSION DISPOSAL PLANS AND PROCEDURES ....................... 16
11 ASSESSMENT OF SPACECRAFT REENTRY HAZARDS ............................................................ 22
12 ASSESSMENT OF SPACECRAFT HAZARDOUS MATERIALS ...................................................... 26



List of Figures
Figure    6-1: OTB Block Diagram.......................................................................................... 6
Figure    6-2: OTB Physical Configuration (units in mm) .............................................................. 7
Figure    6-3: Outline of OTB Satellite Configuration (solar panels removed) .................................... 8
Figure    9-1: OTB DAS output for Collisions with Large Objects .................................................. 14
Figure    10-1: Stowed Drag Augmentation Device ................................................................... 16
Figure    10-2: Stowed Drag Augmentation Device (detailed view) ............................................... 17
Figure    10-3: Drag Augmentation Device Activation Diagram .................................................... 17
Figure    10-4: Deployed State of Drag Augmentation Device ...................................................... 18
Figure    10-5: Drag Augmentation Redundancy Diagram ........................................................... 19
Figure    10-6: Orbital Apogee/Perigee Altitude ..................................................................... 20
Figure    11-1: CAD Representation of the Satellite (with callouts of objects used in DAS simulation) .... 23
Figure    11-2: Cutaway View of OTB (with callouts of objects used in DAS simulation) ...................... 24
Figure    11-3: DAS Output for Requirement 4.7-1 ................................................................... 25


List of Tables
Table    9-1: Critical Units/Surfaces ....................................................................................                                      15
Table    10-1: Drag Augmentation Device Technology TRL .........................................................                                                18
Table    11-1: Modelled Components of the Spacecraft .............................................................                                              22
Table    12-1: Hazardous materials data ...............................................................................                                         26




                                                                                                                                                                  ii
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



1 Applicable Documents
 AD#                      Title                                                                                       Doc. No.               Issue
 AD-1                     NASA Technical Standard NASA-STD-8719.14A (inc.          NASA-STD-                                                 May 25th,
                          Change 1, 25-5-2012) Process for Limiting Orbital Debris 8719.14A                                                  2012
 AD-2                     NASA Debris Assessment Software (DAS)                                                                              v. 2.1.1
 AD-3                     GUIDANCE ON OBTAINING LICENSES FOR SMALL                                                    13-445                 March 15th,
                          SATELLITES                                                                                                         2013
 AD-4                     Background Information on the Orbital Test Bed                                              OTB-DOC-               August 2013
                          Satellite for the FCC                                                                       000639-02


2 Acronyms and Abbreviations
AFRL                     Air Force Research Laboratory
CAD                      Computer Aided Design
DAS                      Debris Assessment Software
DSAC                     Deep Space Atomic Clock
EELV                     Evolved Expendable Launch Vehicle
EOM                      End of Mission
ESPA                     EELV Secondary Payload Adapter
FCC                      Federal Communications Commission
GA-EMS                   General Atomics Electromagnetic Systems
HDRM                     Hold Down Release Mechanism
HDRS                     Hold Down and Release System
JPL                      Jet Propulsion Laboratory
LANL                     Los Alamos National Laboratory
LEO                      Low Earth Orbit
MSA                      Modular Solar Array
N/A                      Not Applicable
NASA                     National Aeronautics and Space Administration
ODAR                     Orbital Debris Assessment Report
OTB                      Orbital Test Bed
PDM                      Power Distribution Module
RF                       Radio Frequency
SERB                     Space Experiments Review Board
USAF                     United States Air Force




                                                                                                                                                                  1
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



3 PREAMBLE
The Orbital Debris Assessment Report (ODAR) has been prepared by GA-EMS for the Orbital Test Bed
(OTB) satellite. It considers in turn each of the requirements for limiting the generation of orbital
debris, as specified in the NASA Technical Standard. As such, this document has been prepared in
accordance with reference [1] using the following software tool:

           DAS software version 2.1.1 [2].

This document supports GA-EMS’ application for an experimental license [3]. Further information on
OTB’s RF system is provided in reference [4].




                                                                                                                                                                  2
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



4 ODAR SELF ASSESSMENT
Orbital Debris Assessment Report Evaluation: Orbital Test Bed (OTB) Mission.

This provides a summary overview of the compliance against requirements. The details for each
requirement are contained within the body of this report. Note: GA-EMS is not responsible for the
launch vehicle ODAR.

 Reqm’t
                                Launch Vehicle                                        Spacecraft                                      Comments
   #


               Complaint        Not         Incomplete      Standard      Compliant       Not          Incomplete      Note: GA-EMS is not responsible for
                              Compliant                       Non-         or N/A       Compliant
                                                           Compliant                                                        the launch vehicle ODAR

  4.3-1.a                                                                     x                                           Compliant – no debris released

   4.3-1b                                                                     x                                           Compliant – no debris released

   4.3-2                                                                      x                                           Compliant – no debris released

   4.4-1                                                                      x                                           Compliant – no credible risk of
                                                                                                                                    explosion

   4.4-2                                                                      x                                             Compliant – end of mission
                                                                                                                                   passivation

   4.4-3                                                                      x                                          N/A – no planned explosions or
                                                                                                                              intentional collisions

   4.4-4                                                                      x                                          N/A – no planned explosions or
                                                                                                                              intentional collisions

   4.5-1                                                                      x                                        Compliant – probability of collision
                                                                                                                                    0.00031

   4.5-2                                                                      x                                        Compliant – probability of collision
                                                                                                                                   0.000506

  4.6-1(a)                                                                    x                                      Compliant – deorbit 23.76 years from
                                                                                                                       EOM or 25.76 years from launch

  4.6-1(b)                                                                    x                                       N/A – atmospheric re-entry disposal

  4.6-1(c)                                                                    x                                       N/A – atmospheric re-entry disposal

   4.6-2                                                                      x                                              N/A – OTB will be in LEO

   4.6-3                                                                      x                                              N/A – OTB will be in LEO

   4.6-4                                                                      x                                         Compliant – significant spacecraft
                                                                                                                        heritage and EOM HDRM heritage

   4.7-1                                                                      x                                        Compliant – no objects expected to
                                                                                                                         survive re-entry, 1:100000000

   4.8-1                                                                      x                                               N/A – no tether on OTB




                                                                                                                                                                  3
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



5 PROGRAM MANAGEMENT AND MISSION OVERVIEW
5.1 Mission Owner and Operator
General Atomics Electromagnetic Systems is headquartered in San Diego, at 3550 General Atomics
Court, San Diego, CA 92121. GA-EMS is the owner and operator of the OTB spacecraft. Operations will
be led out of the GA-EMS Englewood facility at 345 Inverness Drive South, Suite 100, Englewood,
Colorado, 80112.

5.2 Responsible Program / Project Team
William Thompson – Project Manager                                                                  William.Thompson@ga.com
Matt Yavorsky – Systems Engineer                                                                    Matthew.Yavorsky@ga.com
Becky Yoder – Director of Englewood Operations                                                      Becky.Yoder@ga.com

5.3 Foreign Government or Space Agency Participation
There is no foreign government or space agency participation in the mission.

It is noted that a significant payload hosted by the OTB satellite is the Deep Space Atomic Clock (DSAC)
provided by NASA / Jet Propulsion Laboratory (JPL) under sub-contract number 1468935-04 to GA-EMS.

5.4 Mission Schedule Overview
Preliminary Design Review                                      September 16th, 2013
Critical Design Review                                         January 13th, 2014
Flight Readiness Review                                        October 24th, 2017
Proposed Launch Date                                           June 1st, 2018

5.5 Brief Description of the Mission
The Orbital Test Bed (OTB) satellite is a GA-EMS owned and operated small LEO satellite that will
provide an on-orbit test bed for the demonstration of scientific, research and prototype payloads,
subsystems and equipment. A number of hosted payloads are sponsored by external parties:

      1) Deep Space Atomic Clock (DSAC) ― sponsored by the Jet Propulsion Laboratory (JPL) under
         subcontract No 1468935 (http://www.nasa.gov/mission_pages/tdm/clock/).
      2) iMESA-R ― a space weather monitor built by the USAF Academy and sponsored through AFRL
         Space Experiments Review Board (SERB) (http://www.usafa.edu/df/dfe/dfer/centers/sparc).
      3) Modular Solar Array (MSA) ― built by Vanguard and sponsored through AFRL Space Experiments
         Review Board (SERB).
      4) Cremains – sponsored by Celestis, Inc.

In addition, the GA-EMS primary payloads are:

      1) FlexRx ― a new spacecraft RF receiver design.
      2) Radiation Monitor ― a new spacecraft radiation monitor device.
      3) Custom Experimental Solar Panel ― a new solar panel technology.

5.6 Launch Vehicle and Launch Site
SpaceX (Falcon Heavy Launch Vehicle), STP-2 (US Air Force). This is the confirmed launch for this
mission, on which the OTB satellite is a rideshare partner.

The planned launch site is Space Launch Complex 39A at Cape Canaveral AFS.



                                                                                                                                                                  4
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


5.7 Launch Date and Mission Duration
Launch date from end Q1 2018 onwards, currently manifested for June 2018. Mission duration is 2 years.

5.8 Launch and Deployment Profile
OTB will be released from the STP-2 Falcon Heavy into its intended mission orbit. The orbit will be a
720km +/-18.5 km altitude LEO circular orbit of 24 degrees inclination. OTB will remain in this orbit
until the end of the mission.

5.9 Reason for Selection of Operational Orbit
The selection of the operational orbit is primarily based on the timeframe for launch and the available
rideshare launch opportunity, coupled with the desired concept of operations for each of the hosted
payloads. The combination of the payload objectives means a circular LEO orbit that is sufficiently
above the atmosphere to enable a stable platform for the initial tests to be run, particularly for the
JPL sponsored DSAC payload. Additionally the stability of this orbit allows for very few attitude
maneuvers over the mission lifetime which allows for longer stable periods for science data collection.

5.10 Interaction or Potential Physical Interference with other Operational
     Spacecraft
None identified, noting that the low inclination of the orbit places OTB in a different orbit to the ISS,
away from the popular sun-synchronous orbits, and the planned large constellations of satellites such
as OneWeb.




                                                                                                                                                                  5
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                                               ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                                                                               December 2017



6 SPACECRAFT DESCRIPTION
6.1 Physical Description of the Spacecraft
The OTB satellite is an evolution of the ESPA compatible SSTL-150 spacecraft, first flown in 2007 for
LANL (http://www.sst-us.com/downloads/datasheets/sstl_150-feb-09). OTB is an ESPA class spacecraft
with four deployable solar panels. The spacecraft will be operated in a nadir fixed orientation for the
mission duration and requires only seasonal attitude maneuvers to adjust for the position of the Sun
relative to the orbit.

The avionics suite is based on a heritage set of units with minor updates for mission specific
requirements. The OTB platform block diagram is shown in Figure 6-1 and the physical configuration of
the OTB satellite including solar arrays, antennae etc. is shown in Figure 6-2 and Figure 6-3.

 Low Rate Communications                                                                                 Solar Panel
                                                                                                         Experiment
                                                                                                                                            Surrey                               S-Band HR                               S-Band HR
                                                                                                                                           Radiation                                Tx 0                                    Tx 1
                                                                              Surrey Flex                                                   Monitor
                                                                               Receiver                                                                                          28V     CAN                             28V                 CAN
                     LRT-1                                                                                                                28V       CAN
                                                                               28V         CAN
                   CAN   28V

                                                                                                                           Surrey Payloads & High Rate Communications

                                                                                     OBDH                                    Modular Solar                                                                     28V                                   28V
                                                                                                   422




                   28V   CAN                                                                                                  Array (MSA)




                                                                                                                                                                                                       CAN




                                                                                                                                                                                                                                                             CAN
                                                                                OBC750-0                                        Payload                                                                          AIM 0                      AIM 1
                                                                                                   PPS




                                                                                                                                                                        iMESA-R                                                5V      5V
                    SRx-0                                                                                                                                                Payload
                                                                              28V           CAN
                                                                                                   422




                                                                                                                                                                  28V              422
                    SRx-1                                                                                                                                                                            Gyro-0                                                Gyro-1
                                                                                OBC750-1
                                                                                                   PPS




                   28V   CAN
                                                                              28V           CAN                                                 SERB Payloads                                         SS-0                AOCS                             SS-1

                                                                                                                                                                                                      SS-2                                                 SS-3
 Power                                                                                                                                        DSAC Payload
                                                           Body Mounted
                                                              Panels                                                                                                                                 MTM-0                                                 MTM-1

                                                                                          Rxs
                                                                                                                                                              LNA & Filter

                                                                                    CAN          CAN
                                                                                                                                    GPS                                                                      MTQ-0               MTQ-1                 MTQ-2
                                                                  switches
                                                                   Power
                                                Switches




                                                                                                                                   Antenna                              GPS
                                                  BCM




                                                                                                          Power switches
                               CAN



                                     (8 BCRs)




                                                                                                                                                              422         28V
                                      BCM-1




                                                                                                                                                                                 Temp
                                                                                          PDM
 Deployed Panels




                                                                                                                                                                    10MHz
                                                                                                                                                                                                                         28V




                                                                                                                                                                                                                                                     28V
                                                                                                                                                                                               28V




                                                                                                                                                                                                      RW 0                       RW 1                      RW 2
                               CAN




                                                    Rxs                                                                                                           Ion Clock                           CAN                            CAN                   CAN
                                                                                                                                                   10MHz
                                                                                                                                   USO                               unit
                               CAN



                                     (8 BCRs)




                                                                                                                                                             422         28V     Temp
                                      BCM-0




                                                                                                                                  28V    Analog/

                                                    Rxs
                                                                                                                                          Temp                                                 Attitude Safety                                 De-orbit
                                                                                                                                                                                                  Modules                                      Device
                                                             Power switches




                                                                                15 AHr Li-Ion            Temp.
                               CAN




                                                                                                                                                               Payload
                                                Switches




                                                                                   Battery
                                                 BCM




                                                                                                                                                                                                28V




                                                                                                                                        1 analog
                                                                                                                                                   Analog




                                                                                                                                                                                                                               CAN
                                                                                                                                                   /Temp




                                                                                                                                        6 X Temp
                                                                                                                                                            Interface Unit                                   ASM0                                  De-orbit
                                                                              Battery Heaters                                                                    (PIU)                                                                              device
                                                                                    28V          28V                                                        28V         422     CAN
                                                                                                                                                                                                28V




                                                                                                                                                                                                                               CAN




                                                                                                                                                                                                                                               28V           28V
                                                                                                                                                                                                             ASM1



Acronyms: AOCS – Attitude & Orbit Control System; AIM – Attitude Interface Module; BCM – Battery Charge Module; LNA – Low
Noise Amplifier; LRT – Low Rate Transmitter; MTM – Magnetometer; MTQ – Magnetorquer; OBDH – On Board Data Handling;
PCM – Power Conditioning Module; RW – Reaction Wheel; SRx – S Band Receiver; SS – Sun sensor USO – Ultra-stable Oscillator.
                                                                                                   Figure 6-1: OTB Block Diagram




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All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                                            Figure 6-2: OTB Physical Configuration (units in mm)




                                                                                                                                                                  7
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                              Figure 6-3: Outline of OTB Satellite Configuration (solar panels removed)

6.2 Spacecraft Mass at Launch
The total spacecraft mass of OTB at launch is 138kg.

6.3 Dry Mass of Spacecraft at Launch
The total dry mass of OTB at launch is 138kg.

6.4 Description of Propulsion Systems
There are no propulsion systems within the OTB satellite.

6.5 Fluids
There are no propellant, sealed heat pipes, or pressurization tanks within OTB. Consequently a fluid
loading plan / strategy is not required.

OTB will fly the flight proven EnerSys/ABSL 8s10p Lithium-ion battery that employs the SONY 18650HC
cell. The contents of this cell are held at 1 bar with all cells having a pressure release device that
provides a safe rupture to vent ratio in accordance with recommended NASA safety standards. This
battery pack design has flown on over 50 missions including several flown by SSTL.

6.6 Attitude Control
The co-ordinate system of OTB is indicated in Figure 6-2, with the Earth pointing on the Z-axis, the
velocity vector along the X-axis and the orbital normal along the Y-axis.

The OTB satellite utilizes three SSTL designed and built heritage reaction wheels (10sp-m-small-
satellite-microwheel) for attitude control, together with three SSTL heritage magnetorquers for de-


                                                                                                                                                                  8
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


saturation of the reaction wheels. In addition, sun sensors, gyros and magnetometers also form part of
the Attitude & Orbit Control System as shown in the block diagram, Figure 6-1.

6.7 Range Safety or other Pyrotechnic Devices
There are no pyrotechnic devices within the OTB satellite.

6.8 Electrical Generation and Storage System
The OTB bus has four deployable solar panels and four body-mounted panels, of which two are hosted
payloads, see Figure 6-2. The power from the solar panels is used to charge a flight proven ABSL 8s10p
Lithium-Ion battery manufactured by ABSL (http://www.enersys.com/) which provides an unregulated
power supply to downstream subsystems. The system and battery have been designed in order to
complete the mission even if there is a string failure on the battery or the solar arrays.

Power is supplied from the battery to the Power Distribution Module (PDM) units. The PDM controls the
switching of the 28V unregulated battery supply to spacecraft subsystems.

6.9 Other Sources of Stored Energy
The deployable solar panels are deployed using the SSTL hold down and release system (HDRS, see
section 7.1). No debris is produced during solar panel deployment.

6.10 Radioactive Materials
There are no radioactive materials onboard the OTB satellite.




                                                                                                                                                                  9
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



7 ASSESSMENT OF SPACECRAFT DEBRIS RELEASED DURING NORMAL
  OPERATIONS
7.1 Objects Expected to be released from the Spacecraft any time after Launch
There are no intentional releases from OTB; all deployment systems are self-contained entities
designed not to release debris into the environment.

The deployment systems are:

      1) SSTL Hold Down and Release System

The Hold Down and Release System (HDRS) for the deployable solar panels utilizes captive devices on
both sides of the interface (retention of bolt and springs) and as such does not generate debris. This
system has been used successfully on previous SSTL spacecraft and as such is TRL9 Flight Proven.

      2) Planetary Systems Corporation Separation System (‘Lightband’)

Planetary Systems Corporation states within their 2000785 Rev C User’s Manual for Mark II Lightband,
2nd April 2013 (section 3, point 5): Non-pyrotechnic. The Lightband generates no debris on or after
separation’ and is a TRL 9 system. http://www.planetarysystemscorp.com/#!__products/mark-ii-
motorized-lightband.

      3) Drag Augmentation Device

The drag augmentation device is based on flight proven technologies and components. This system is
further explained in section 10.

7.2 Spacecraft Compliance with Requirements 4.3-1 and 4.3-2
Requirement 4.3-1: Debris passing through LEO – released debris with diameters of 1mm or larger:

      a) Requirement 4.3-1a: All debris released during the deployment, operation, and disposal phases
         shall be limited to a maximum orbital lifetime of 25 years from date of release (Requirement
         56398).

Compliant ― no debris released during normal operations.

      b) Requirement 4.3-1b: The total object-time product shall be no larger than 100 object-years per
         mission (Requirement 56399). The object-time product is the sum of all debris of the total time
         spent below 2,000 km altitude during the orbital lifetime of each object. (See section 4.3.4.2
         for methods to calculate the object-time product.)

Compliant ― no debris released during normal operations.

Requirement 4.3-2: Debris passing near GEO: For missions leaving debris in orbits with the potential of
traversing GEO (GEO altitude +/- 200 km and +/- 15 degrees latitude), released debris with diameters
of 5 cm or greater shall be left in orbits which will ensure that within 25 years after release the apogee
will no longer exceed GEO - 200 km (Requirement 56400). DAS will be used to assess compliance
against these requirements.

Compliant ― no debris released during normal operations.




                                                                                                                                                                 10
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



8 ASSESSMENT OF SPACECRAFT INTENTIONAL BREAKUPS AND
  POTENTIAL FOR EXPLOSIONS
8.1 Potential Causes of Spacecraft Breakup during Deployment and Mission
    Operations
The spacecraft is a heritage design and has undergone rigorous structural acceptance testing during
qualification. There are no pressurized systems on board, and no propulsion system.

OTB will fly the flight proven ABSL 8s10p Lithium-ion battery that employs the commercial SONY
18650HC cell. The contents of this cell are held at 1 bar with all cells having a pressure release device
that provides a safe rupture to vent ratio in accordance with recommended NASA safety standards.

No credible potential causes of spacecraft breakup during deployment or mission operations are
foreseen.

8.2 Summary of Failure Modes and Effects Analyses of all Credible Failure Modes
    which may lead to an Accidental Explosion
The only device that stores a sufficient amount of energy to cause an accidental explosion is the flight
proven, heritage ABSL 8s10p battery. This unit has flown on over 50 spacecraft to date and the SONY
18650HC cell that it employs has accrued more than 50,000 cell years in orbit without any safety
events in space. Before launch, the battery is charged and then disconnected from the spacecraft. It is
only connected to the spacecraft power system upon separation from the launch vehicle so it presents
no credible risk during the launch phase of the mission.

Upon separation and during operations, the battery will be cycled at a benign depth of discharge of
less than 15% with an end of charge voltage of 32.8V. The power system is a heritage design and has
battery charge and discharge safety functionality that has been proven on numerous other SSTL
spacecraft including CFESat, RapidEye, UK-DMC-2, Deimos and exactView-1.

There are three possible failure modes for the battery:

      1) Overcharge of Lithium-ion batteries above the recommended maximum end of charge voltage
         of 33.6V could result in thermal runaway. To prevent this, the battery voltage is constantly
         monitored by the power subsystem and charging is halted if this voltage is exceeded. This
         functionality has been tested and verified using the OTB power subsystem. As a second level of
         protection, in the event of the failure of this safety circuitry, the ABSL 8s10p cells contain
         internal protection devices that result in an open circuit shutting down the entire battery. This
         functionality has been demonstrated via a number of ground tests.

      2) Short circuit of Lithium-ion batteries can result in very high current draw that leads to heating
         and could invoke thermal runaway. To prevent this, the spacecraft has fused or switched power
         lines to all components so that high current draw effects are halted before the battery can be
         affected. As an additional level of protection, in the event of fuse failure, the ABSL 8s10p cells
         carry short circuit protection devices that detect a rise in temperature and increase the
         internal resistance reducing current flow mitigating a rise in temperature.

      3) Over discharge of the ABSL 8s10p, where the battery is taken below the minimum
         recommended operating voltage of 20V, has been proven by test to degrade battery
         performance but not pose a safety risk. Over-discharge tests where ABSL 8s10p cells have been
         driven to negative voltage have been shown to result in a safe failure with cells effectively
         becoming resistors. In addition, the power system of the satellite will switch off below 23V to
         limit the discharge of the battery below this point.


                                                                                                                                                                 11
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


The SONY 18650HC cells in the ABSL 8s10p battery have had thermal runaway testing performed, which
showed that in the event of a single cell thermal runaway with other cells in healthy conditions
propagation does not occur. As such, even thermal runaway of a single cell (which is protected against
through the mechanisms described above) has not been shown to cause an explosion.

In summary, there are no credible failure modes which would cause an accidental explosion and the
battery design has been sufficiently tested to insure that thermal runaway propagation does not occur.

8.3 Detailed Plan for any Designed Spacecraft Breakup
There are no intentional breakups ― explosions nor intentional collisions ― planned.

8.4 List of Components which are Passivated at EOM
At End of Mission (EOM), all units except the power system and the RF receivers will be turned off. The
battery will continue to charge and discharge at a very low depth of discharge to the nominal end of
charge level set via telecommand. The design of the heritage power system is such that the battery
cannot be disconnected from the power system at EOM.

Reaction wheels are stopped in a controlled manner as part of EOM operations and switched off.

An end of charge voltage of 31V will be selected (the minimum possible) that will result in the battery
being at a state of charge < 50% and minimize the energy available for any failure event. Ground and
in-orbit life test data indicate an expected graceful degradation of the battery with effective battery
capacity reducing over time, leading to a benign state through the absence of useful capacity. With the
end of charge voltage set to 31 V any additional charging capacity will be dissipated from the radiator
surface.

8.5 Rationale for Items which cannot be Passivated due to their Design
Please see response to section 8.4 on the battery. The battery cannot be completely passivated
(discharged to 0% state of charge and disconnected from the power system) due to heritage system
design and power system which have successfully flown on numerous SSTL missions.

8.6 Spacecraft Compliance with Requirements 4.4-1 through 4.4-4
Requirement 4.4-1: Limiting the risk to other space systems from accidental explosions during
deployment and mission operations while in orbit about Earth or the Moon: For each spacecraft and
launch vehicle orbital stage employed for a mission, the program or project shall demonstrate, via
failure mode and effects analyses or equivalent analyses, that the integrated probability of explosion
for all credible failure modes of each spacecraft and launch vehicle is less than 0.001 (excluding small
particle impacts) (Requirement 56449).

Compliant ― GA-EMS see no credible risk of spacecraft explosion (caused by the spacecraft itself
without external impact) during launch, nominal operations and the time between EOM and Earth re-
entry (Refer to section 8.1).

Requirement 4.4-2: Design for passivation after completion of mission operations while in orbit about
Earth or the Moon: Design of all spacecraft and launch vehicle orbital stages shall include the ability
and a plan to deplete all on-board sources of stored energy and disconnect all energy generation
sources when they are no longer required for mission operations or post mission disposal or control to a
level which cannot cause an explosion or deflagration large enough to release orbital debris or break up
the spacecraft (Requirement 56450)

Compliant.



                                                                                                                                                                 12
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                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


Requirement 4.4-3: Limiting the long-term risk to other space systems from planned breakups: Planned
explosions or intentional collisions shall:

      a) Be conducted at an altitude such that for orbital debris fragments larger than 10 cm the
         object-time product does not exceed 100 object-years (Requirement 56453). For example, if
         the debris fragments greater than 10cm decay in the maximum allowed 1 year, a maximum of
         100 such fragments can be generated by the breakup.

      b) Not generate debris larger than 1 mm that remains in Earth orbit longer than one year
         (Requirement 56454).

Not applicable ― OTB will not undertake any planned explosions or intentional collisions.

Requirement 4.4-4: Limiting the short-term risk to other space systems from planned breakups:
Immediately before a planned explosion or intentional collision, the probability of debris, orbital or
ballistic, larger than 1 mm colliding with any operating spacecraft within 24 hours of the breakup shall
be verified to not exceed 10-6 (Requirement 56455).

Not applicable ― OTB will not undertake any planned explosions or intentional collisions.




                                                                                                                                                                 13
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



9 ASSESSMENT OF SPACECRAFT POTENTIAL FOR ON-ORBIT
  COLLISIONS
9.1 Probability of Collision with Space Objects > 10 cm in diameter
The NASA DAS software [2] was used to assess compliance of the OTB spacecraft with Requirement 4.5-
1. For this analysis, the average area-to-mass ratio was used. This represents the spacecraft following
the deployment of the drag augmentation devices and in tumble. In order to calculate this the
maximum cross-sectional area was identified, and with the two orthogonal areas, the average cross-
sectional area was calculated using the accepted NASA formula. (Note that the maximum cross-
sectional area, with the drag augmentation device deployed, is not orthogonal to the plane of the
deployed solar panels.) The resulting area-to-mass ratio is calculated to be 0.0329m2/kg. The mission
duration of 2 years was listed as this is the controlled mission lifetime. The DAS software takes into
account the full orbital lifetime until deorbit.

The probability of collision with large objects was calculated to be 0.00031 during the orbital lifetime
(Figure 9-1), which is compliant with the requirement. Additional analysis was performed to confirm
that the deployment of the drag augmentation device does not increase the probability of collision to a
level greater than that if no device was used.




                                       Figure 9-1: OTB DAS output for Collisions with Large Objects

9.2 Probability of Collision with Space Objects of sufficient size to prevent Post-
    Mission Disposal
The units listed in Table 9-1 are critical to completing post-mission disposal activities. Each unit is
listed with its individual Probability of Penetration value, as calculated by DAS [2]. The OTB spacecraft
will enter the EOM phase of operations in the nominal, nadir-pointing attitude, and it will remain nadir-


                                                                                                                                                                 14
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


pointing until the deorbit device is deployed. The critical surface of the units will therefore be in the
plane of the direction of motion.

During the EOM phase, the flight computer will receive the deorbit command from the ground through
the S-band patch antennas and the receiver. The onboard computer will then command the deorbit
device to deploy, which will begin to deorbit the spacecraft. For these actions to occur, the power
system must also be active.

An extra level of protection to the critical units is provided by our standard dual-redundant design
approach. Each of the units listed in Table 9-1, aside from the deorbit device, are redundant. In the
unlikely event of a unit being damaged during the operational phase, the deorbit device could still be
deployed by the redundant components. See section 10 for further discussion.

                                                          Table 9-1: Critical Units/Surfaces

                         Critical Surface                                                    Probability of Penetration
                         Drag Augmentation HDRM                                              0.000000
                         OBC                                                                 0.000067
                         PDM                                                                 0.000014
                         Battery                                                             0.000010
                         RF Tray                                                             0.000012
                         Antennas                                                            0.000405
                         TOTAL PROBABILITY OF PENETRATION                                    0.000508


The total probability of post-mission disposal failure is 0.000508, which is compliant with the
requirement.

9.3 Spacecraft Compliance with Requirements 4.5-1 and 4.5-2
Requirement 4.5-1: Limiting debris generated by collisions with large objects when operating in Earth
orbit: For each spacecraft and launch vehicle orbital stage in or passing through LEO, the program or
project shall demonstrate that, during the orbital lifetime of each spacecraft and orbital stage, the
probability of accidental collision with space objects larger than 10 cm in diameter is less than 0.001
(Requirement 56506).

Compliant ― the probability of collision with large objects was calculated by DAS [2] to be 0.00031
during the orbital lifetime, which is compliant with the requirement, Figure 9-1.

Requirement 4.5-2: Limiting debris generated by collisions with small objects when operating in Earth
or lunar orbit: For each spacecraft, the program or project shall demonstrate that, during the mission
of the spacecraft, the probability of accidental collision with orbital debris and meteoroids sufficient
to prevent compliance with the applicable post mission disposal requirements is less than 0.01
(Requirement 56507).

Compliant ― the probability of accidental collision with orbital debris and meteoroids sufficient to
interfere with post-mission disposal was calculated by DAS [2] to be 0.000508, which is compliant with
the requirement, Table 9-1.




                                                                                                                                                                 15
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



10 ASSESSMENT OF SPACECRAFT POSTMISSION DISPOSAL PLANS AND
   PROCEDURES
10.1 Spacecraft Disposal
The spacecraft will deorbit naturally by atmospheric re-entry following the deployment of a drag
augmentation device. This device has been designed in order to increase the average cross-sectional
area of the satellite at the end-of-mission (EOM) to deorbit OTB while utilizing simple mechanical
principles and the “KISS” philosophy ― focusing on the simplicity and robustness of the device.

OTB will carry a drag augmentation device that is based on the following on-orbit demonstrated
technologies:

           Carbon fiber slit-tube booms ― successfully demonstrated on orbit through the Roll Out Solar
            Array (ROSA) mission and also a sub-orbital launch of a NASA Terrier Improved Malemute
            sounding rocket.

           Aerospace rated Kapton materials featuring rip-stop features ― typical for thermal blankets on
            satellites and common in the industry.

           Industry standard Frangibolt release mechanisms ― since 1994, the Frangibolt has been
            qualified and used on numerous space applications.

The drag augmentation device will be stowed on the Earth facing facet of the spacecraft, shown in
Figure 10-1, for launch as well as the expected mission duration of 2 years. At EOM, the device will be
activated by sending an Arm and Fire command set. Deployment of the drag augmentation device only
requires that the Frangibolt releases; the rolled carbon fiber slit-tube’s stored mechanical energy
ensures deployment upon release. With the drag augmentation device deployed the spacecraft can
then be passivated for final disposal. The spacecraft does not need to be controlled through re-entry as
the system has been designed to deorbit within the required period in a random tumbling orientation.




                                                Figure 10-1: Stowed Drag Augmentation Device



                                                                                                                                                                 16
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                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


Drag Augmentation Device

The drag augmentation device uses composite slit-tube booms manufactured by ROCCOR, benefitting
from their extensive experience with this technology. This boom technology is combined with the
industry standard TiNi Frangibolt release mechanism and heritage Dunmore materials to effectively
increase the drag cross-sectional area of OTB at EOM. The stowed configuration of the drag
augmentation device is shown in Figure 10-2.




                                     Figure 10-2: Stowed Drag Augmentation Device (detailed view)

Frangibolts operate through the expansion of a shape memory alloy that increases the preload of a
specially designed titanium bolt to the point of fracture at a designed fracture point. The Frangibolt is
implemented so that both sides of the restraint bolt are retained by the system, the threaded section
in the base of the drag augmentation device and the head of the bolt remains connected to a hold-
down strap that is also connected to the base of the drag augmentation device. At no time is there a
potential for the fractured bolt to be released as debris.

Upon activation, the Frangibolt will release the constrained wrapped composite slit tube allowing its
stored energy to unroll the entire wrapped composite material, without need for any active or
electrically-powered components, or mechanical springs; in other words allowing it to unroll naturally.
There are no further mechanical or electrical elements to the device, and no additional commands
required to fully deploy the drag augmentation device (as illustrated by Figure 10-3). The deployed
state of the system is shown in Figure 10-4. Each deployed device will be 0.45 m wide and 3.8 m long.


          EOM Reached –                   ARM Command                     FIRE Command                                                Composite Slit Tube
         De-Orbit Decision             Issued from Mission             Issued from Mission            Frangibolt TiNi Fired           Unfurls & De-Orbit
              Made                      Operations Center               Operations Center                                                Commences



                                        Figure 10-3: Drag Augmentation Device Activation Diagram

The design is based upon proven technologies and components (shown in Table 10-1) and the
development and testing of the device is subject to the same rigor as every other subsystem on the
satellite. The utilization of these technologies for a drag augmentation device represents a simple and
robust method to help address the growing concern of EOM disposal.




                                                                                                                                                                 17
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                                         Figure 10-4: Deployed State of Drag Augmentation Device

                                           Table 10-1: Drag Augmentation Device Technology TRL

                       Key Technology                                                                                 Maturity
                       Composite Slit-Tube Boom                                                                       TRL-9
                       Mylar or Kapton Sail (Dunmore)                                                                 TRL-9
                       Hold Down Release Mechanism, HDRM (TiNi Frangibolt)                                            TRL-9


Composite slit-tube boom technology is used in a wide variety of on-orbit applications, both current
and planned. Examples include small satellite de-orbit devices (RODEO), radar booms, antenna booms,
solar array booms. In comparison to the uses listed here, the application in the OTB deorbit device is
very simple, being shorter, with no hinges, and not supporting the mass of a full solar array or antenna.

The Roll-Out DeOrbiting (RODEO) device boom was self-deploying, meaning the stored strain energy of
the packaged boom provided the necessary deployment force; as per the device being implemented on
OTB. RODEO was ultimately successfully demonstrated through a flight experiment conducted as part
of the Colorado Space Grant Consortium’s (COSGC) RocketSat-8 program
(http://esmats.eu/amspapers/pastpapers/pdfs/2014/turse.pdf). During the flight experiment the
deployment was slower than expected but continued in short bursts until reaching full deployment. It
was determined, and verified through on-ground tests, that this was caused by moisture saturation in
the composite boom, plasticizing the resin and reducing the stiffness and stored strain energy of the
boom. The effect is completely reversible and the boom would deploy as expected after drying out—
the multiple starts and stops observed in the flight experiment indicated that as the outer layers of the
boom dried out, the boom was gradually able to reach full deployment. Moisture absorption will not be
an issue for the OTB satellite mission since the boom will have ample time to completely dry out in the
hard vacuum of space prior to deployment at end-of-mission life.

System Reliability

The drag augmentation system has been designed to incorporate multiple redundancies as well as high
reliability components, proven in orbit, in order to ensure the effective disposal of the spacecraft at
EOM. This redundancy is incorporated at three levels:

           Activation
           Release
           Performance

                                                                                                                                                                 18
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                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                 ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                 December 2017


Activation redundancy is achieved through the spacecraft platform design, including the electrical
power system and switch architecture. The deployment of the drag augmentation device is controlled
by the power system through a system of series switches. This allows for Arm and Fire commanded
switches to ensure that the deployment only takes place when commanded at EOM. These Arm and Fire
switches are also configured so that each pair has a redundant circuit in the event of a failure of one of
the sets. The commanding of these switches also contains a built in redundancy in that the commands
come directly from the onboard computer (OBC), but in the event of a critical system failure with the
OBC the switches can still be commanded simply through the RF system via emergency, low-level
commanding.

The redundancy inherent in the platform system design for the subsystems required to activate the
drag augmentation device is illustrated in Figure 10-5. There are no single point failures present in the
platform elements required for activation, with at least one-layer of redundancy. This is our standard
design approach, used on numerous missions, which have demonstrated 100% mission success over the
last 15 years.



                                                                                                   Primary Drag
                                                  Primary On-Board                                                     Primary TiNi Heater
                         Primary RF Receiver                                                       Augmentation
                                                      Computer                                                              Element
                                                                                                  Device Switches
                                                                          Power System –
  Mission Operation                                                      Power Disribution                                                         De-Orbit Device
 Center Commanding                                                           (Internally                                                           Frangibolt TiNi
                                                                            Redundant)
                                                                                                  Redundant Drag
                           Redundant RF             Redundant On-                                                       Secondary TiNi
                                                                                                   Augmentation
                             Receiver              Board Computer                                                       Heater Element
                                                                                                  Device Switches




                                               Figure 10-5: Drag Augmentation Redundancy Diagram

Release redundancy is inherit to the TiNi Frangibolts through the use of primary and secondary heater
circuits. In the event that the primary heating element is damaged or is unable to release the
Frangibolt the secondary heating circuit can be used. This ensures that the Frangibolt successfully
deploys.

The drag augmentation system has also been designed to have inherit performance redundancy by
being designed to deorbit the system well within the required timeline, as described below. This
additional margin provides further confidence for uncertainty in atmospheric models.

Figure 10-6 shows the lifetime plot for the OTB satellite after deployment of the drag augmentation
device at end of mission. Assuming a launch date of 2018, with a 2 year mission lifetime, OTB will
deorbit within 25.76 years from launch (less than the required 30 years for total on-orbit time). Note
that the calculation assumes random tumble of the OTB satellite after deployment.




                                                                                                                                                                     19
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                                                  Figure 10-6: Orbital Apogee/Perigee Altitude

10.2 Systems or Components required to accomplish Post-Mission Disposal
Section 10.1 outlines the required components for successful post mission disposal. Section 8.4 details
those devices passivated at EOM.

Note that the end-of-mission operational plan is to deploy the de-orbit device and then passivate the
satellite. The commands to passivate can be received by the satellite when it is in any orientation, due
to the placement of the receive antennas. This antenna placement is a requirement for spacecraft
early operations, when initially separated from the launch vehicle in a tumbling state.

10.3 Spacecraft Maneuvers required to accomplish Post-Mission Disposal
No maneuvers are required for the proper deployment of the drag augmentation device.

10.4 Area-to-Mass Ratio after Post-Mission Disposal
Spacecraft Mass: 138 kg
Cross-sectional Area: 4.545 m2
Area to mass ratio: 0.0329 m2/kg

The probability of collision with large objects was calculated by DAS [2] to be 0.00031 during the
orbital lifetime, please see section 9.1 for further analysis.

10.5 Spacecraft Compliance with Requirements 4.6-1 through 4.6-4
Requirement 4.6-1: Disposal for space structures in or passing through LEO: A spacecraft or orbital
stage with a perigee altitude below 2,000 km shall be disposed of by one of the following three
methods: (Requirement 56557)

      a) Atmospheric reentry option:


                                                                                                                                                                 20
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                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


                 Leave the space structure in an orbit in which natural forces will lead to atmospheric
                  reentry within 25 years after the completion of mission but no more than 30 years after
                  launch; or
                 Maneuver the space structure into a controlled deorbit trajectory as soon as practical after
                  completion of mission.

      b) Storage orbit option: Maneuver the space structure into an orbit with perigee altitude greater
         than 2000 km and apogee less than GEO - 500 km.

      c) Direct retrieval: Retrieve the space structure and remove it from orbit within 10 years after
         completion of mission.

The OTB satellite reentry is compliant using reentry option “a”.

Requirements 4-6-1(b) and 4-6-1(c) are not applicable.

Requirement 4.6-2: Disposal for space structures near GEO: A spacecraft or orbital stage in an orbit
near GEO shall be maneuvered at EOM to a disposal orbit above GEO with a predicted minimum perigee
of GEO +200 km (35,986 km) or below GEO with an apogee of GEO – 200 km (35,586 km) for a period of
at least 100 years after disposal (Requirement 56563).

Not applicable. OTB will be in LEO.

Requirement 4.6-3: Disposal for space structures between LEO and GEO:

a. A spacecraft or orbital stage shall be left in an orbit with a perigee greater than 2000 km above the
Earth’s surface and apogee less than 500 km below GEO (Requirement 56565).

b. A spacecraft or orbital stage shall not use nearly circular disposal orbits near regions of high value
operational space structures, such as between 19,200 km and 20,700 km (Requirement 56566).

Not applicable. OTB will be in LEO.

Requirement 4.6-4: Reliability of post mission disposal operations in Earth orbit: NASA space programs
and projects shall ensure that all post mission disposal operations to meet Requirements 4.6-1, 4.6-2,
and/or 4.6-3 are designed for a probability of success as follows: (Requirement 56567)

      a) Be no less than 0.90 at EOM.

      b) For controlled reentry, the probability of success at the time of reentry burn must be
         sufficiently high so as not to cause a violation of Requirement 4.7-1 pertaining to limiting the
         risk of human casualty.

SSTL has a long heritage of successful missions, 49 spacecraft launched to date with over 500 years
collectively on orbit, in part due to the multiple points of redundancy built into every mission design
with a design life of 5 years or more. The drag augmentation device, Frangibolt based, has a minimum
reliability of 0.99999 ― this is the supplier published reliability for the TiNi Frangibolt and is the
industry standard with 20 years of space heritage. The OTB satellite is an “SSTL-150 ESPA” which is
listed in the NASA Rapid III catalogue; it has a Ps of 92%. (Noting that SSTL have not had a mission
failure on-orbit in over 15 years, and none with this class of satellite.)This gives us confidence that
OTB will be able to complete its 2 year mission and successfully deploy the drag augmentation devices
at EOM, with a Ps = 0.91999.

4.6.4b N/A ― OTB does not have a controlled re-entry.


                                                                                                                                                                 21
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



11 ASSESSMENT OF SPACECRAFT REENTRY HAZARDS
11.1 Spacecraft Components by Size, Mass, Material, Shape, and Original Location
Table 11-1 summarizes the major components of the spacecraft, which were input into the DAS
software [2]. According to the DAS user’s guide, the main structure of a spacecraft is assumed to break
apart at an altitude of 78 km, exposing the first level of “child” objects to atmospheric forces. All of
the objects in the table below are of this first level, and make up the mass of the spacecraft which
enters the atmosphere.

                                             Table 11-1: Modelled Components of the Spacecraft

 No.             Object Name                               Qty        Material              Shape                    Mass (kg)         Dimensions (m)
 (refer                                                                                                                                Box: W x L x H
 to                                                                                                                                    Plate: W x L
 figures)                                                                                                                              Cylinder: Diameter x L
      1          OTB                                       1          Aluminum              Box                      138               0.574 x 0.859 x 0.574
      2          Deployed Solar Panel                      4          Aluminum              Flat Plate               2.22              0.580 x 0.934
      3          Body Solar Panel                          3          Aluminum              Flat Plate               1.04              0.55 x 0.55
      4          DSAC Ion Clock                            1          Aluminum              Box                      16.1              0.260 x 0.285 x 0.229
      5          DSAC USO                                  1          Aluminum              Box                      1.52              0.2 x 0.24 x 0.11
      6          DSAC GPS Receiver                         1          Aluminum              Box                      3.6               0.18 x 0.25 x 0.12
      7          DSAC GPS Antenna                          1          Aluminum              Cylinder                 0.7               0.242 x 0.090
      8          Top Bay Structural Panels                 4          Aluminum              Flat Plate               1.8               0.230 x 0.580
      9          iMESA-R (SERB Payload)                    1          Aluminum              Box                      1.14              0.105 x 0.118 x 0.035
     10          Stack Structural Panels                   4          Aluminum              Flat Plate               1.08              0.232 x 0.358
     11          Radiator Panels                           1          Aluminum              Flat Plate               2.99              0.580 x 0.700
     12          Earth Facing Panel                        1          Aluminum              Flat Plate               2.54              0.543 x 0.543
     13          DSAC Bay Structure Panels                 2          Aluminum              Flat Plate               1.16              0.236 x 0.543
     14          Antennas                                  7          Aluminum              Box                      0.25              0.082 x 0.082 x 0.067
     15          AOCS Actuators                            3          Aluminum              Box                      0.5               0.2 x 0.2 x 0.2
     16          Battery                                   1          Aluminum              Box                      4.00              0.159 x 0.221 0.068
     17          AOCS Sensors                              8          Aluminum              Box                      0.35              0.15 x 0.15 x 0.15
     18          Harness                                   1          Copper                Flat Plate               10.00             0.2 x 0.4
     19          Nanotray                                  2          Aluminum              Box                      3.00              0.135 x 0.190 x 0.055
     20          Top Bay Floor Plate                       1          Aluminum              Flat Plate               3.86              0.547 x 0.547
     21          AIM (Custom Tray)                         1          Al 7075-T6            Box                      7.679             0.515 x 0.547 x 0.037
     22          S-Band Tx/Rx                              1          Aluminum              Box                      2.576             0.286 x 0.314 x 0.047
     23          OBC 750 0/1                               1          Aluminum              Box                      1.994             0.286 x 0.314 x 0.032
     24          F7 PDM                                    1          Aluminum              Box                      1.741             0.286 x 0.314 x 0.041
     25          BCM 80 1                                  1          Aluminum              Box                      2.553             0.286 x 0.314 x 0.035
     26          BCM 80 0 (Custom Tray)                    1          Al 7075-T6            Box                      6.850             0.420 x 0.421 x 0.060
     27          MLB                                       1          Aluminum              Box                      2.219             0.381 x 0.381 x 0.053
     28          HDRM                                      4          Aluminum              Cylinder                 0.960             0.120 x 0.093
     29          Spacer Ring                               1          Aluminum              Box                      0.973             0.381 x 0.381 x 0.019
     30          MSA                                       2          Aluminum              Flat Plate               0.185             0.200 x 0.310
     31          ASM                                       1          Aluminum              Box                      0.885             0.515 x 0.547 x 0.037
     32          10-SP Wheel                               3          Aluminum              Cylinder                 1.022             0.100 x 0.100
     33          SFF                                       1          Aluminum              Flat Plate               1.832             0.515 x 0.555
     34          HRTx                                      2          Aluminum              Box                      1.8               0.146 x 0.191 x 0.11

                                                                                                                                                                 22
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017


 No.             Object Name                               Qty        Material              Shape                    Mass (kg)         Dimensions (m)
 (refer                                                                                                                                Box: W x L x H
 to                                                                                                                                    Plate: W x L
 figures)                                                                                                                              Cylinder: Diameter x L
     35          GPS Antenna Plate                         1          Aluminum              Flat Plate               1.485             0.284 x 0.312
     36          FlexRx                                    1          Aluminum              Box                      0.320             0.164 x 0.191 x 0.11
     37          RadMon                                    1          Aluminum              Box                      0.700             0.068 x 0.100 x 0.063
     38          Monopole antenna                          2          Aluminum              Cylinder                 0.250             0.060 x 0.150
     39          Shear Panel                               2          Aluminum              Flat Plate               1.160             0.284 x 0.546
     40          Screen                                    2          Aluminum              Flat Plate               0.200             0.264 x 0.555
     41          Shear Panel +Y                            1          Aluminum              Flat Plate               2.961             0.515 x 0.522
     42          Deorbit Sail                              2          Aluminum              Flat Plate               1.0               0.450 x 3.800



Please refer to Figure 11-1 and Figure 11-2 for indication of the object positions on the OTB satellite
(objects 36 & 37 not shown are contained behind object 8).




            Figure 11-1: CAD Representation of the Satellite (with callouts of objects used in DAS simulation)




                                                                                                                                                                 23
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                 Figure 11-2: Cutaway View of OTB (with callouts of objects used in DAS simulation)
       Solar panels and some of the closing panels are removed for clarity (objects 11, 18, 39, & 40 not shown)

11.2 Objects expected to survive an Uncontrolled Re-entry
No objects from OTB are expected to survive uncontrolled re-entry, as calculated using the DAS
software [2].

11.3 Probability of Human Casualty
Using DAS [2] calculated results in the above table; total probability of human casualty is 1:100000000,
or 0.00000001 (10-8) which is compliant to the requirement, Figure 11-3.

11.4 Spacecraft Compliance with Requirement 4.7-1
Requirement 4.7-1: Limit the risk of human casualty: The potential for human casualty is assumed for
any object with an impacting kinetic energy in excess of 15 joules:

      a) For uncontrolled reentry, the risk of human casualty from surviving debris shall not exceed
         0.0001 (1:10,000) (Requirement 56626).

Using the DAS software [2], OTB is compliant to requirement 4.7-1, as the probability for human
casualty does not exceed 1:10000 or 0.0001, Figure 11-3.




                                                                                                                                                                 24
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017




                                                Figure 11-3: DAS Output for Requirement 4.7-1




                                                                                                                                                                 25
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.


OTB-DOC-000638-05                                ODAR FOR THE ORBITAL TEST BED (OTB) SATELLITE                                                  December 2017



12 ASSESSMENT OF SPACECRAFT HAZARDOUS MATERIALS
12.1 Hazardous Materials contained on the Spacecraft
Lithium exists within the flight proven ABSL 8s10p lithium-ion battery which employs the commercial
SONY 18650HC cell. The quantity and state of the lithium is shown in Table 12-1.

Trace amounts of mercury exist within the Deep Space Atomic Clock Ion Clock unit which is part of the
DSAC experiment. The quantity and state of the mercury is shown in Table 12-1.

                                                       Table 12-1: Hazardous Materials Data

 Material                   Material                Material at         Material                 Material at          Material at              Material
 Description                Hazard                  Launch              During                   EOM                  Passivation              Surviving
                            Presented                                   Operations                                                             Re-entry
 Lithium                    Ignition when           Solid, 24g,         Solid, 24g,              Solid, 24g,          Solid, 24g,              None
                            in contact              Ambient             Ambient                  Ambient              Ambient
                            with water,
                            corrosive
 Mercury                    Toxic in liquid         Gas,                Gas, 100µg,              Gas,                 Gas, 100µg,              None
                            and gas form            100µg,              10e-8 Torr               100µg,               10e-8 Torr
                                                    10e-8 Torr                                   10e-8 Torr




                                                                                                                                                                 26
All information contained in this document is proprietary and confidential to GA-EMS and shall not, in whole or in part, be reproduced or disclosed, or used for any
                              purpose other than for which it is provided, without GA-EMS prior written consent. All rights reserved.



Document Created: 2018-01-30 16:56:38
Document Modified: 2018-01-30 16:56:38

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