It is an interesting set of challenges which are several orders of magnitude greater than a 1U with a Z axis magnet in LEO.

Of course there is a de-risking strategy where the 25yr orbital debris rule can be mitigated by flying an elliptical orbit. e.g Geostationary transfer orbit.. Then just wait for perigee reduction to do your re-entry for you.
V+U band will work with omni antennas.  Modern digital modes will work nicely at apogee, while simple ground stations can use the lower part of the orbit. - What an incentive to improve your station!

If you really need S C or X band with directional antennas on the satellite, then the attitude can be adjusted with magnetorquers during perigee.

No fuel required.....If you can identify a launch with a perigee that's high enough.  If not, then a 1/2U pulsed plasma thruster may be able to nudge it up a little every apogee.

Good luck. It's a tough assignment.

David G0MRF
New and proposed U.S. regulatory restrictions are creating significant obstacles (and in some cases, barriers ) in our path.  In addition, the de facto CubeSat form factor requires us to downsize and even shoehorn many of the necessary systems into a spacecraft no larger than a loaf of bread (3U) or small briefcase (6U).  As an example, finding a micro-propulsion system that will satisfy our delta-v budget for achieving attitude and orbit control, orbital transfers, and end-of-life deorbiting or a move-away-and-stay-away storage solution, is one such challenge.  If that’s not enough, we have to find a propellant safe enough to satisfy launch provider restrictions. 



-----Original Message-----
From: Robert Bankston via AMSAT-BB <amsat-bb@amsat.org>
To: AMSAT BB <amsat-bb@amsat.org>
Sent: Fri, 5 Nov 2021 0:27
Subject: [AMSAT-BB] Looking to HEO

Returning to higher Earth orbits (HEO) is proving to be more complicated than past AMSAT’s missions.  New and proposed U.S. regulatory restrictions are creating significant obstacles (and in some cases, barriers ) in our path.  In addition, the de facto CubeSat form factor requires us to downsize and even shoehorn many of the necessary systems into a spacecraft no larger than a loaf of bread (3U) or small briefcase (6U).  As an example, finding a micro-propulsion system that will satisfy our delta-v budget for achieving attitude and orbit control, orbital transfers, and end-of-life deorbiting or a move-away-and-stay-away storage solution, is one such challenge.  If that’s not enough, we have to find a propellant safe enough to satisfy launch provider restrictions.  I know that doing more with less has always been the unofficial motto of AMSAT, but this was generally in reference to our project funding.  Now, we have to take that same approach to our design of CubeSat sub-systems, capable of operating in higher Earth orbits.
  
A ride-share opportunity (similar to AMSAT-DL’s amateur radio integration aboard Es'hail 2 / QO-100) would certainly make our return to HEO easier.  Unfortunately, finding a geostationary prospect over the Western Hemisphere has proven to be harder than we hoped.  Absent a gift from the satellite gods, we need to press on with designing, building, and operating our own HEO spacecraft.
  
NASA JPL’s Mars Cube One (MarCO) CubeSats could offer invaluable design cues for our own HEO-bound spacecraft.  In 2018, NASA launched two, 6U CubeSats to Mars, to serve as communication-relays in support of NASA’s InSight Mars lander mission.  These CubeSats featured deployable solar panels, X-band communications, a deployable reflectarray antenna, and a cold-gas micro-propulsion system.  Additionally, each CubeSats' attitude-control system combined a star tracker, Sun sensors, gyroscopes, and three-axis reaction wheels for monitoring and adjusting orientation.
  
The total cost of NASA’s Mars Cube One mission was $18 million.  Hopefully, our return to HEO will be a fraction of that cost.
  

73,

Robert Bankston, KE4AL
President
Radio Amateur Satellite Corporation (AMSAT)

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