Rev ODAR

0616-EX-PL-2015 Text Documents

Aerospace Corporation, THE

2016-02-24ELS_173193

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.
      1.1          21 January           15+                Removed               D. Hinkley
                      2016           Appendices        propulsion from         MicroSatellite
                                                           SHERPA              Systems Dept.
                                                          description




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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
 4.3-1a    be limited to a maximum orbital lifetime of 25 years from date of release.            Compliant     no debris.
           The total object-time product shall be no larger than 100 object-years per                          ISARA will release
 4.3-1b    mission.                                                                              Compliant     no 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                   planned explosions
 4.4-3     product does not exceed 100 object-years, and b) not generate debris larger           Compliant     or intentional
           than 1 mm that remains in Earth orbit longer than one year.                                         collisions.
                                                                                                               ISARA has no
           Immediately before a planned explosion or intentional collision, the probability
                                                                                                               planned explosions
 4.4-4     of debris, orbital or ballistic, larger than 1 mm colliding with any operating        Compliant     or intentional
           spacecraft within 24 hours of the breakup shall be verified to not exceed 10-6.
                                                                                                               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
           less than 0.90 at EOM.                                                                              is 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
 4.8-1     requirements limiting the generation of orbital debris from on-orbit collisions       Compliant     tether system.
           and the requirements governing post-mission disposal.

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ISARA ODAR                                                                The Aerospace Corporation




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.

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


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ISARA ODAR                                                                                  The Aerospace Corporation


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
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, power system, and orbit determination capability, which allows
for the release of the secondary payloads into an orbit that ensures atmospheric reentry for the


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ISARA ODAR                                                                   The Aerospace Corporation


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
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 gyro will be used to

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ISARA ODAR                                                                  The Aerospace Corporation


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 of
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ISARA ODAR                                                                   The Aerospace Corporation


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
 2                                       See Failure Mode #4.
       high 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
 3
       charge rate                       internal chemical that forms a gas) that occurs during
                                         overcharging conditions.
                                         The bus batteries have an internal positive temperature
       Excessive discharge rate or
                                         coefficient (PTC) device that acts as a resettable fuse during
 4     short circuit due to external
                                         external short circuit that limits the cell output current during
       device failure
                                         such an event.
                                         Vents have access through the structure that holds them and
 5     Inoperable vents                  into the larger satellite volume. Venting will not be inhibited by
                                         physical obstructions.
                                         Satellite body and internal design prevent loads on battery
 6     Crushing
                                         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
       discharge combined                in 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.



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ISARA ODAR                                                                   The Aerospace Corporation


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

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
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Requirement 4.5-2: COMPLIANT

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: 2016-02-24 08:54:21
Document Modified: 2016-02-24 08:54:21

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