Mission Design Dave Curtis UCB/SSL Space Sciences Laboratory University of California, Berkeley

1. Mission Design • Dave Curtis • UCB/SSL • Space Sciences Laboratory • University of California, Berkeley

2. Mission Design Agenda • AGENDA Launch Configuration Early Orbit Commissioning Science Operations Issues

3. Launch Configuration • Launch configuration constrained by: • CubeSat Design Specification (rev 12) • 3U P-POD container defines envelope • MAG Boom, UHF Antennas stowed • Limited access prior to launch • Powered off for launch • Battery disabled by deployment switch • No deployments and RF transmissions until 30 minutes after CubeSat deployed from P-Pod • Launch Vehicle (TBD) • Launch Environment (vibration, thermal vac) – assume NASA GEVS (GSFC-STD-7000) until launch vehicle selected • Orbit, Deployed spin state

4. Early Orbit – First Operations • CubeSat spin state TBD at deployment • Depends on launch vehicle • Some tumble likely due to tip-off • Processor powered up on CubeSat deployment • Processor powers up in SAFE mode; Instrument Off, Transmitter Off, UHF Receiver On • Flight Software will deploy UHF Antennas 30 minutes after deployment to listen for first contact • MAG boom may also be automatically deployed after 30 minutes – TBD • Helps with passively detumbling and setting moments of inertia

5. Early Orbit – ACS? • ACS may automatically start de-tumble - TBD • Or may wait for ground command • May improve communications • Wait for lack of communication before automatically starting up ACS? • How to determine this is initial power-up? • Don’t want to start de-tumble if this is some later processor reset • Maybe some launch state setting in non-volatile memory? • Requires automatic promotion out of SAFE mode into ACS mode • Power up Instrument Interface Board, MAG [but note STEIN] • Enable ACS torque coils • Work with Inboard MAG, Sun Sensors, Solar Array Currents • Outboard MAG cannot be used until orientation determined

6. Early Orbit - First Contact • First contact will probably be with Berkeley Ground Station (BGS) • Time of first pass can probably be pre-determined based on launch time, planned orbit • Flight Software will probably power on the transmitter automatically based on predicted time from deployment to first pass • Plus/minus some margin • Transmitter on aids BGS tracking • Real time housekeeping transmitted • BGS will lock on, command dump of recorded housekeeping when good link achieved • Contingency plans in place at the MOC to deal quickly with off-nominal situations • Failure to make first contact will return CINEMA to SAFE mode where it will wait to be contacted • Details of first pass depend on orbit, to be determined when we get a launch selected

7. Early Orbit - Subsequent Contacts • We will need orbit predicts to build a pass plan • Orbit predicts will quickly become insufficient • NORAD 2-line elements should be available soon after launch • Tracking based on BGS track information is difficult but possible • Once we have a pass plan, BGS will know how and when to point BGS antenna, and time-tagged sequences can be built and uplinked to control CINEMA downlink • UHF receiver is always on • If CINEMA ends up in SAFE mode or we lose contact for some reason we should be able to command the transmitter on and diagnose the situation assuming we know where CINEMA is

8. Commissioning • ACS needs to orient CINEMA • detumble, spin up, and precess to Sun Normal spinner, precess to Ecliptic Normal spinner – see ACS presentation • Limited automation; the ground will be involved, particularly in the last step • MAG Boom must be deployed and Outboard MAG orientation must be determined (using torque coils) • Once ACS has oriented CINEMA, promote to Science Mode • STEIN is powered up and tested • Power budget probably does not allow STEIN and ACS at the same time • Operations Requires planning to deal with the lack of much real time communication • Only a few ~7 minute passes/day

9. Science Operations • After completion of ACS orientation, Instrument commissioning start Science Operations • Communications and Instrument Modes will be based on a time-tagged command list uploaded periodically (once/day?) from the ground • Operations may be constrained during eclipse by power issues, lack of ACS information • Occasional return to ACS mode to maintain spin orientation is required • Every few days, by ground command • STEIN powered off in ACS mode

10. Issues • Determine Launch Opportunity • Sets initial spin state, orbit • Decide if MAG boom is automatically deployed • Decide if ACS detumble is started automatically