1 ISARA ODAR v1

0616-EX-PL-2015 Text Documents

Aerospace Corporation, THE

2015-09-24ELS_167471

ISARA ODAR                                                                 The Aerospace Corporation


    Integrated Solar Array and Reflectarray Antenna (ISARA)
                  Orbital Debris Assessment Report (ODAR)
                                Report Version: 1.0, 2 April 2015


      Prepared for NASA in compliance with NPR 8715.6A by The Aerospace Corporation.

    This document contains proprietary information of The Aerospace Corporation and is not
                                  suitable for public release.

                         Software used in this analysis: NASA DAS v2.0.2



 Revision           Date              Pages             Description              Author
   1.0           2 April 2015          15+              First version,          J. Wilson,
                                    Appendices       requires signatures   Astrodynamics Dept.




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ISARA ODAR                                                                  The Aerospace Corporation




                         VERSION APPROVAL and FINAL APPROVAL*:




                   The Aerospace Corporation               NASA Concurrence**




                   Dr. Richard Hodges                      NASA HQ Office of
                   ISARA                                   Safety   and    Mission
                   Principal Investigator                  Assurance Orbital Debris
                   The Aerospace Corporation               Manager




                   Darren Rowen                            Mission      Directorate
                   ISARA                                   Associate Administrator
                   Program Manager
                   The Aerospace Corporation




                   Dr. James Nokes                         NASA Program Manager
                   Principal Director
                   Space Materials Laboratory
                   The Aerospace Corporation


* Approval signatures indicate acceptance of the ODAR-defined risk.

** Signatures required only for Final ODAR




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ISARA ODAR                                                                                               The Aerospace Corporation


Self-Assessment of Requirements per NASA-STD 8719.14A
                                                                                                Compliance
Requirement                                                                                                    Comments
                                                                                                Assessment
          All debris released during the deployment, operation, and disposal phases shall                      ISARA will release no
4.3-1a    be limited to a maximum orbital lifetime of 25 years from date of release.            Compliant      debris.
          The total object-time product shall be no larger than 100 object-years per                           ISARA will release no
4.3-1b    mission.                                                                              Compliant      debris.
          For missions leaving debris in orbits with the potential of traversing GEO,                          ISARA will not
          released debris with diameters of 5 cm or greater shall be left in orbits which
4.3-2     will ensure that within 25 years after release the apogee will no longer exceed       Compliant      operate in or near
          GEO-200 km.                                                                                          GEO.
          For each spacecraft employed for a mission, the program or project shall
4.4-1     demonstrate…that the integrated probability of explosion for all credible             Compliant
          failure modes of each spacecraft is less than 0.001.
          Design of all spacecraft shall include the ability and a plan to deplete all
          onboard sources of stored energy and disconnect all energy generation sources
4.4-2     when they are no longer required for mission operations or post-mission               Compliant
          disposal or control to a level which cannot cause an explosion or deflagration
          large enough to release orbital debris or break up the spacecraft.
          Planned explosions or intentional collisions shall: a) be conducted at an                            ISARA has no
          altitude such that for orbital debris fragments larger than 10 cm the object-time
4.4-3     product does not exceed 100 object-years, and b) not generate debris larger           Compliant      planned explosions or
          than 1 mm that remains in Earth orbit longer than one year.                                          intentional collisions.
          Immediately before a planned explosion or intentional collision, the probability                     ISARA has no
4.4-4     of debris, orbital or ballistic, larger than 1 mm colliding with any operating        Compliant      planned explosions or
          spacecraft within 24 hours of the breakup shall be verified to not exceed 10-6.                      intentional collisions.
          For each spacecraft in or passing through LEO, the program shall demonstrate
4.5-1     that, during the orbital lifetime of each spacecraft, the probability of accidental   Compliant
          collision with space objects larger than 10 cm in diameter is less an 0.001.
          For each spacecraft, the program shall demonstrate that, during the mission of
          the spacecraft, the probability of accidental collision with orbital debris and                      ISARA will use
4.5-2     meteoroids sufficient to prevent compliance with the applicable post-mission          Compliant      natural orbit decay.
          disposal requirements is less than 0.01.
          A spacecraft with a perigee altitude below 2000 km shall be disposed of by one
          of the following three methods: a) leave the space structure in an orbit in which
          natural forces will lead to atmospheric reentry within 25 years, b) maneuver                         ISARA will use
4.6-1     the space structure into a controlled de-orbit trajectory, c) maneuver the space      Compliant      natural orbit decay.
          structure into an orbit with perigee altitude above 2000 km and apogee less
          than GEO-500 km.
                                                                                                               ISARA will not
          A spacecraft or orbital stage in an orbit near GEO shall be maneuvered at EOM
4.6-2     to a disposal orbit above GEO.                                                        Compliant      operate in or near
                                                                                                               GEO.
          For space structures between LEO and GEO, a spacecraft shall be left in an                           ISARA will not
          orbit with a perigee greater than 2000 km above the Earth’s surface and apogee
4.6-3     less than 500 km below GEO, and a spacecraft shall not use nearly circular            Compliant      operate in or near
          disposal orbits near regions of high-value operational space structures.                             MEO.
          NASA space programs shall ensure that all post-mission disposal operations to                        Evaluation of
4.6-4     meet the above requirements are designed for a probability of success of no           In Progress    deployable system is
          less than 0.90 at EOM.                                                                               in progress
          For uncontrolled reentry, the risk of human casualty from surviving debris
4.7-1     shall not exceed 0.0001.                                                              Compliant
          Intact and remnants of severed tether systems in Earth orbit shall meet the
                                                                                                               ISARA has no tether
4.8-1     requirements limiting the generation of orbital debris from on-orbit collisions       Compliant      system.
          and the requirements governing post-mission disposal.




NOTE: ISARA is currently manifested to fly as a secondary payload. Compliance with
requirements levied by NASA-STD 8719.14A on the launch vehicle will be the responsibility of
the primary payload and/or launch provider.
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ISARA ODAR                                                                The Aerospace Corporation


Section 1: Program Management and Mission Overview
Mission Directorate: The Aerospace Corporation, Space Materials Laboratory

Program Executive: Dr. James Nokes



Principal Investigator: Dr. Richard Hodges, Jet Propulsion Laboratory

Program Manager: Darren Rowen, The Aerospace Corporation



Foreign government or space agency participation: none



Nominal Schedule of Mission Design and Development:



                         Event                                Date
                         Project initiation                   9 Aug 2012
                         System Requirements Review (SRR)     23 Apr 2013
                         Preliminary Design Review (PDR)      12 Nov 2013
                         Critical Design Review (CDR)         15 Apr 2015
                         Flight Readiness Review (FRR)        15 Dec 2015
                         Delivery                             15 Jan 2016
                         Target launch date                   1 Mar 2016


Brief Description of the Mission: The Integrated Solar Array and Reflectarray Antenna
(ISARA) mission will demonstrate a high bandwidth Ka-band antenna for satellite
communications in the CubeSat form factor. The primary payload, a reflectarray antenna, is
designed to provide up to 100 Mbps data rate with minimal impact to satellite mass, volume, or
power. The reflectarray is integrated to the underside of a deployable solar array panel, which
provides power for Ka-band transmission and nominal mission operations. Currently, NASA
rates the reflectarray as a TRL 5 technology. ISARA will perform direct, on-orbit measurements
of the antenna gain to mature the reflectarray to a TRL 7.

The reflectarray is printed to the underside of the solar panels, which is 30 cm x 70 cm, and will
provide at least 35 dB of gain at 26 GHz. The reflectarray is complemented by a 1 cm by 2 cm
patch antenna etched into the solar array that acts as a feed to obtain good taper and spillover

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ISARA ODAR                                                                                  The Aerospace Corporation


efficiency. By maturing the TRL, it is expected that this reflectarray design could become a
practical high gain antenna option for 3U (30 cm x 10 cm x 10 cm) and larger CubeSats.




                         Figure 1. The ISARA spacecraft with reflectarray/solar cells deployed.




Identification of the anticipated launch vehicle and launch site: ISARA has been manifested
as a secondary payload with FORMOSAT-5, which will fly on a Falcon 9 launch scheduled for
March 2016. ISARA will be deployed using the SHERPA deployment system along with 83
other CubeSats. SHERPA, which is manufactured by Andrews Space, is designed from an EELV
Secondary Payload Adapter (ESPA) ring to fit on U.S. Medium and Intermediate launch vehicles
(e.g. EELV, Falcon 9, Antares). SHERPA contains an avionics system that controls the release
of its payloads such that no release will interfere with the primary payload deployment.
SHERPA has an independent flight computer, propulsion system, power system, and orbit
determination capability, which allows for the release of the secondary payloads into an orbit
that ensures atmospheric reentry for the released payloads. SHERPA will deploy ISARA to a
roughly 425 km x 720 km altitude orbit inclined 97.4°.



Identification of the proposed launch date and mission duration: The ISARA mission
anticipates a launch as a secondary payload in March 2016. The main mission phase is

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ISARA ODAR                                                                 The Aerospace Corporation


approximately 5 months. The stretch mission will extend the operational lifetime to at least 2
years.

Description of the launch and deployment profile: As a secondary payload, the ISARA
spacecraft will be deployed from the launch vehicle to minimize risk to the primary payload and
upper-stage space structures. Secondary payload deployment will occur after deployment of the
primary payload. Typically, after deploying the primary payload, the upper stage performs a
small burn to alter the orbit (eliminating the risk of collision with the primary) before releasing
any secondary payloads.

Reason for selection of operational orbit: As a secondary payload, ISARA has no control over
the selection of operational orbit. ISARA can perform its mission in any LEO orbit, although the
altitude must be low enough to ensure natural decay and reentry within the timeframe specified
by NPR8751.6A. The altitude to which the SHERPA deployment vehicle and its payloads will
be delivered (including ISARA) satisfies that requirement.

Identification of any interaction or potential physical interference with other operational
spacecraft: As one of several dozen CubeSats deployed by SHERPA, there is a small risk of
contact between ISARA and another CubeSat. The timing of satellite deployments from
SHERPA is intended to mitigate this risk as much as possible. Debris mitigation for the
deployment process is the responsibility of SHERPA. In the event of contact shortly after
deployment, the relative velocities between CubeSats is on the order of centimeters per second,
which would not provide enough force to cause catastrophic breakup of the satellites or generate
significant amounts of debris (the glass coverings of solar cells may crack). The launch vehicle
trajectory and mission plan is designed to ensure there is no risk to the primary payload. There is
no anticipated risk to any other operational spacecraft.




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ISARA ODAR                                                                The Aerospace Corporation


Section 2: Spacecraft Description
Physical Description: The ISARA mission consists of a three unit (3U) CubeSat with
dimensions 30 x 10 x 10 cm. The satellite contains a Sun sensor and Earth sensor, RF
communications antennae, GPS receiver, a medium-field camera, and narrow-field camera. The
30 cm x 70 cm solar panels will extend off the anti-nadir side of ISARA.




                                   Figure 2. Internal layout of ISARA.




Total spacecraft mass at launch: < 5 kg

Dry mass of spacecraft at launch: < 5 kg

Description of all propulsion systems: ISARA has no propulsion system.

Identification of all fluids planned to be on board: ISARA carries no fluids on board.

Description of all active and/or passive attitude control systems with an indication of the normal
attitude of the spacecraft with respect to the velocity vector: ISARA has 3-axis attitude control
via three torque rods and three “pico” reaction wheels. The torque rods are a mutually orthogonal
triad of coiled wire, wrapped around a high magnetic permeability alloy that can generate a
magnetic dipole of 0.15 to 0.2 A-m2 when the satellite passes current through the wire. The rods
generate negligible magnetic field when powered off. The torque rods are made from 35.5 cm-
diameter mu-metal rods that are 5.5 cm long. The pico reaction wheels have flight heritage on
three AeroCube-4 and two AeroCube-5 spacecraft. Attitude sensors include Earth nadir sensors,
two-axis Sun sensors on various spacecraft surfaces, a 3-axis magnetometer, and two star
trackers of the same type and model that will fly on AeroCube-7. A high-accuracy 3-axis rate

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ISARA ODAR                                                                  The Aerospace Corporation


gyro will be used to provide an inertial attitude reference when 0.7° or better pointing accuracy is
required and the Sun and Earth are not simultaneously visible by an appropriate sensor, and a
medium-resolution 3-axis rate gyro and 3-axis magnetometer will serve as a backup.

Description of any range safety or other pyrotechnic devices: ISARA has no pyrotechnic
devices.

Description of the electrical generation and storage system: Power for ISARA is generated by
solar cells mounted onto panels that will be deployed from the anti-nadir side of the bus, as well
as cells affixed to the spacecraft bus. These cells are capable of producing up to 22 W of power.
Power is stored on-board with lithium-ion batteries. The satellite has 4 batteries mounted in an
aluminum 6061-T6 structure as a unit and are shock and thermally isolated by a low-outgassing
rubber grommet. Each battery is composed of two cells. Two batteries are rated at 9 W-hr while
the other two are rated at 6 W-hr, for a total of 30 W-hr on the spacecraft. Specific details of the
batteries’ manufacture appear in Section 4.

Identification of any other sources of stored energy: There are no other sources of stored
energy on ISARA.

Identification of any radioactive materials on board: ISARA carries no radioactive materials.




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ISARA ODAR                                                                  The Aerospace Corporation


Section 3: Assessment of Spacecraft Debris Released during Normal
Operations
Identification of any object (>1 mm) expected to be released from the spacecraft any time
after launch: ISARA will release no objects into space during normal operations.

Rationale/necessity for release of each object: N/A

Time of release of each object, relative to launch time: N/A

Release velocity of each object with respect to spacecraft: N/A

Expected orbital parameters (apogee, perigee, inclination) of each object after release: N/A

Calculated orbital lifetime of each object, including time spent in LEO: N/A

Assessment of spacecraft compliance with Requirements 4.3-1 and 4.3-2:

Requirement 4.3-1a: COMPLIANT

Requirement 4.3-1b: COMPLIANT

Requirement 4.3-2: COMPLIANT



Section 4: Assessment of Spacecraft Intentional Breakups and
Potential for Explosion
Identification of all potential causes of spacecraft breakup during deployment and mission
operations: There is no credible scenario that would result in spacecraft breakup during normal
deployment and operations.

Summary of failure modes and effects analyses of all credible failure modes that may lead
to an accidental explosion:

Battery risk: A possible malfunction of the lithium ion or lithium polymer batteries or of the
control circuit has been identified as a potential, but low probability, cause of accidental breakup
or explosion. Natural degradation of the solar cells and batteries will occur over the post-mission
period and poses an increased chance of undesired battery-energy release. The battery capacity
for storage will degrade over time, possibly leading to changes in the acceptable charge rate for
the cells. Individual cells may also change properties at different rates due to time degradation
and temperature changes. The control circuit may also malfunction as a result of exposure over
long periods of time. The cell pressure relief vents could be blocked by small contaminants. Any
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ISARA ODAR                                                                  The Aerospace Corporation


of these individual or combined effects may theoretically cause an electro-chemical reaction that
results in rapid energy release in the form of combustion.

Notwithstanding these potential sources of energy release, ISARA still meets Requirement 4.4-2
as the on-board batteries cannot “cause an explosion or deflagration large enough to release
orbital debris or break up the spacecraft.” Underwriters Laboratories (UL) certifies the batteries
used on ISARA. In general, these batteries are similar in size and power to cell- phone batteries.



                                                            Number of     Energy Stored per
   Model Number (UL Listing)         Manufacturer
                                                              Cells             Cell
              ICR18650H                  Molicel               2              <9 W-hr
             IBR18650BC                  Molicel               2              <6 W-hr


The batteries are consumer-oriented devices. The batteries have been recognized as UL tested
and approved. UL recognition has been determined through the UL Online Certifications
Directory, which clearly shows that these cell batteries have undergone and passed UL
Standards. Furthermore, safety devices incorporated in these batteries include pressure release
valves, over-current charge protection, and over-current discharge protection.

The fact that the ISARA batteries are UL recognized indicates that they have passed the UL
standard testing procedures that characterize their explosive potential. Of particular concern to
NASA is UL Standard 1642, which specifically deals with the testing of lithium batteries.
Section 20 Projectile Test of UL 1642 subjects the test battery to heat by flame while within an
aluminum- and steel-wire-mesh octagonal box, “[where the test battery] shall remain on the
screen until it explodes or the cell or battery has ignited and burned out” (UL 1642 20.5). To pass
the test, “no part of an exploding cell or battery shall penetrate the wire screen such that some or
all of the cell or battery protrudes through the screen” (UL 1642 20.1).

It is reasonable to expect the batteries on ISARA to experience similar conditions during their
orbital life span. While the sources of failure would not be external heat on orbit, analysis of the
expected mission thermal environment shows that given the low power dissipation for CubeSats,
the batteries will be exposed to a maximum temperature well below their 212° F (100° C) safe
operation limit. Continual charging with 2 to 6 W average power from the solar panels over an
orbital life span greater than 12 years may expose the batteries to overcharging, which could
cause similar heat to be generated internally. Through the UL recognition and testing, it has been
shown that these batteries do not cause an explosion that would cause a fragmentation of the
spacecraft.



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ISARA ODAR                                                                           The Aerospace Corporation


In addition to the aforementioned certification of the ISARA batteries against explosion, ten
potential failure modes for lithium batteries and their applicability or mitigation in ISARA are
addressed in the following table:

     Failure Mode                        Applicability or Mitigation
                                         The ISARA body and internal design prevents deformation or
1    Internal short circuit
                                         crushing of the batteries that could lead to internal short circuit.
     Internal thermal rise due to high
2                                        See Failure Mode #4.
     load discharge rate
                                         The battery cells on ISARA have charge interrupt devices that
     Overcharging and excessive          activate during cell internal pressure buildup (due to cell internal
3
     charge rate                         chemical that forms a gas) that occurs during overcharging
                                         conditions.
     Excessive discharge rate or         The bus batteries have an internal positive temperature coefficient
4    short circuit due to external       (PTC) device that acts as a resettable fuse during external short
     device failure                      circuit that limits the cell output current during such an event.
                                         Vents have access through the structure that holds them and into
5    Inoperable vents                    the larger satellite volume. Venting will not be inhibited by
                                         physical obstructions.
6    Crushing                            Satellite body and internal design prevent loads on battery cases.
     Low level current leakage or
     short circuit through battery
7                                        Satellites are stored in a controlled environment.
     pack case or due to moisture-
     based degradation of insulators
                                         Thermal sensors on the batteries provide telemetry on battery
     Excess temperatures due to          temperature. There is no cutoff for overheating batteries except
8    orbital environment and high        whatever is inherent in the cell itself. However, as noted earlier in
     discharge combined                  this section of the ODAR, the batteries on ISARA are UL-
                                         certified as non-explosive in over-heating scenarios.
     Polarity reversal due to over-      A 2.7 V discharge cutoff threshold circuit in ISARA has been
9
     discharge                           verified in acceptance tests for the electric power system.
     Excess battery temperatures due
     to post-mission orbital         The circuit that charges the batteries cannot exceed 4.1 V and
10
     environment and constant        therefore will never overcharge the batteries.
     overcharging


Through a combination of UL certification, compliance with AFSPCMAN 91-710 V3
requirements, and an understanding of the general behavior of the failure modes associated with
these types of batteries, it is possible to conclude that the batteries meet Requirement 4.4-2.

Detailed plan for any designed breakup, including explosions and intentional collisions:
ISARA has no plans for intentional breakups, explosions, or collisions.

List of components, which are passivated at EOM: No systems on ISARA will be passivated
at EOM.

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ISARA ODAR                                                                 The Aerospace Corporation


Rationale for all items which are required to be passivated, but cannot due to their design:
As described above, the batteries do not present a debris-generation hazard per Requirement 4.4-
2, and in the interest of not increasing the complexity of the ISARA power system, it was
decided not to passivate the batteries at EOM.

Assessment of spacecraft compliance with Requirements 4.4-1 through 4.4-4:

Requirement 4.4-1: COMPLIANT

Requirement 4.4-2: COMPLIANT

Requirement 4.4-3: COMPLIANT

Requirement 4.4-4: COMPLIANT



Section 5: Assessment of Spacecraft Potential for On-Orbit
Collisions
Collision probabilities have been calculated using DAS v2.0.2 with the assumptions: 425 km x
720 km altitude orbit, 97.7° inclination, 5 kg mass (initial and final), and 0.0154 m2/kg area-to-
mass ratio (the maximum-area configuration).

In addition to the DAS analysis, The Aerospace Corporation has performed additional analysis
looking at the collision probability of ISARA with 0th-, 1st-, and 2nd-generation debris objects
with 95th-, 50th-, and 5th-percentile solar cycle assumptions. The probability of collision for all
cases considered is below the 0.001 requirement. A summary of the Aerospace analysis is
appended to this ODAR.

Calculation of spacecraft probability of collision with space objects larger than 10 cm in
diameter during the orbital lifetime of the spacecraft: Probability = 0.00000, per DAS v2.0.2

Calculation of spacecraft probability of collision with space objects, including orbital
debris and meteoroids, of sufficient size to prevent post-mission disposal: Because the
mission has selected natural de-orbit (see Section 6) for disposal and no systems will be
passivated at EOM (see Section 4), small debris do not pose a threat to prevent post-mission
disposal.

Assessment of spacecraft compliance with Requirements 4.5-1 and 4.5-2:

Requirement 4.5-1: COMPLIANT

Requirement 4.5-2: COMPLIANT
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ISARA ODAR                                                                 The Aerospace Corporation


Section 6: Assessment of Spacecraft Post-mission Disposal Plans and
Procedures
Description of spacecraft disposal option selected: The ISARA mission has selected
atmospheric reentry for disposal. The vehicle is a 30 x 10 x 10 cm bus. The vehicle’s mass is
approximately 5 kg. The longest possible orbital lifetime occurs if the vehicle were permanently
aligned nadir with the smallest face pointing in the direction of motion, with a cross-sectional
area of 310 cm2. Although in practice after EOM the vehicle will tumble with a higher “average”
cross-sectional area of 770 cm2, the analysis in DAS assumed the worst-case low-drag
configuration for lifetime. DAS evaluates a lifetime of 9.057 years, using the orbit assumptions
listed at the beginning of Section 5 (except for using a lower area-to-mass ratio of 0.0062 m2/kg).
This lifetime is compliant with ODAR requirements. Assuming the predicted nominal post-
mission cross-sectional area of 770 cm2, DAS predicts a lifetime of 6.412 years.

This lifetime analysis assumes that the solar panels properly deploy. In the event of a deployment
failure, the worst-case cross-sectional area becomes 100 cm2. This again requires active attitude
control, which will not be the case. The orbital lifetime calculated by DAS is 28.912 years,
which exceeds the 25-year lifetime requirement. Even though ISARA will have no attitude
control at the end of its mission and will tumble (which would reduce its orbital lifetime to
16.515 years, per DAS), The Aerospace Corporation has taken steps to ensure that solar panel
deployment reliability is greater than 0.9, as required by NASA-STD 8719.14 Section 4.6.4.3,
which states that a valid debris assessment “includes two areas: (1) design or component failure
which leads to loss of control during the mission and (2) failure of the postmission disposal
system. Total reliability for postmission disposal operations not involving directed reentry is
0.90.”

Area (2) of Section 4.6.4.3 is satisfied by the insertion of ISARA into an orbit with perigee lower
than 700 km, as recommended by NASA-STD 8719.14 Section 4.6.5. Area (1) is satisfied by
demonstrating that solar panel deployment, which increases the post-mission cross-sectional area
to 770 cm2, has a reliability greater than 0.9. Solar panel deployment involves two systems,
communications and the solar panel deployment mechanism. The communications system,
which is necessary for solar panel deployment, has flown on previous CubeSat missions,
including The Aerospace Corporation’s AeroCube-4 and AeroCube-5 missions, with a reliability
greater than 0.99. The solar panel deployment mechanism itself is heritage hardware from The
Aerospace Corporation’s AeroCube-7 mission, which begins operations in May 2015. Flight
experience with the deployment mechanism will allow the team to assess its reliability.
Furthermore, the deployment mechanism is resettable, which allows for additional attempts at
deployment in the event of deployment failure. Compliance of Requirement 4.6-4 is in progress,
but should be favorably resolved by the Flight Readiness Review.

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ISARA ODAR                                                               The Aerospace Corporation


In addition to the DAS analysis, The Aerospace Corporation has performed additional analysis
looking at the orbital lifetime of ISARA assuming several different perigee and apogee altitudes
in the event the main payload or SHERPA deployment vehicle deliver ISARA into an off-
nominal orbit. In all cases studied, with the exception of SHERPA deploying ISARA into a
circular sun-synchronous orbit above 620 km, the lifetime is below the 25-year requirement. The
risk of deploying ISARA and the other secondary payloads into this kind of orbit is assumed to
be negligible. A summary of the Aerospace analysis is appended to this ODAR in Appendix A.

Identification of all systems or components required to accomplish any post-mission
disposal operation, including passivation and maneuvering: As discussed in Section 4, no
disposal or passivation is planned for ISARA. Natural orbit decay is sufficient to terminate the
mission.

Plan for any spacecraft maneuvers required to accomplish post-mission disposal: None

Calculation of area-to-mass ratio after post-mission disposal, if the controlled reentry
option is not selected: N/A

Preliminary plan for spacecraft controlled reentry: N/A

Assessment of compliance with Requirements 4.6-1 through 4.6-4:

Requirement 4.6-1: COMPLIANT

Requirement 4.6-2: COMPLIANT

Requirement 4.6-3: COMPLIANT

Requirement 4.6-4: COMPLIANT




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ISARA ODAR                                                                The Aerospace Corporation


Section 7: Assessment of Spacecraft Reentry Hazards
Detailed description of spacecraft components by size, mass, material, shape, and original
location on the space vehicle, if the atmospheric reentry option is selected: The ISARA
vehicles are primarily constructed of aluminum and PCB electronic board material. The only
components with a higher density or resistance to melting are ceramic path antennas, nine nickel-
iron alloy torque rods, and three small stainless steel reaction wheels. The DAS analysis, which
is in Appendix B, shows these materials pose no risk per the ODAR requirement.

Summary of objects expected to survive an uncontrolled reentry: No objects are expected to
survive uncontrolled reentry.

Calculation of probability of human casualty for the expected year of uncontrolled reentry
and the spacecraft orbital inclination: Zero

Assessment of spacecraft compliance with Requirement 4.7-1:

Requirement 4.7-1: COMPLIANT

Section 8: Assessment for Tether Missions
The ISARA mission has no tether. All requirements are COMPLIANT.

Sections 9–14: Assessment of Launch Vehicle Debris
ISARA will fly as a secondary payload. Assessment of launch-vehicle debris is the responsibility
of the primary payload. These sections are N/A for ISARA.




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Document Created: 2015-09-23 18:45:25
Document Modified: 2015-09-23 18:45:25

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