Question about propulsion and orbit control technology


#1

A few questions about propulsion and orbit control technology.

Will the outernet satellites use tethers or other forms of propellant-less propulsion?

Tethers: e.g. the Momentum-eXchange/Electrodynamic-Reboost (MXER) tether system.
Tethers for orbit control, going to higher or lower orbit.
www.centauri-dreams.org/?p=9189

The tethers can also be used at the end of life to make the satellite leave orbit much faster than letting the orbit decay and pose a hazard to other satellites.
Site at: science.nasa.gov/science-news/science-at-nasa/1998/ast15oct98_1/
If yes, will tethers be used for these purposes?

There are already tethers designed specifically for cubesats.

Solar sails:
Will the team use solar sails?:
(For anyone not familiar with solar sails, check out the wikipedia article about them.)
If yes, for what tasks?

Will there be collision avoidance or formation flight by propellant-less systems?
Something like this: http://www.eng.umd.edu/html/media/release.php?id=208

Will the team pursue other methods of propellant less propulsion for the satellites?


#2

These are all great questions. Generally speaking, we’ll be sticking to proven technology, as much as possible. The reason for that is to reduce the amount of risk associated with constellation deployment and operations, as well as to reduce research and development costs. COTS (commercial off the shelf) components are heavily influencing the design decisions.

Tethers are a great idea, as a matter of fact, the University of Michigan has a nifty experiment scheduled for this year. If they, or anyone else, are able to prove the technology out, then we could very well be revisiting the plans. As of now, though, we’re trying not to include any propulsion, as it adds an increased layer of complexity and cost to the system. We are striving to keep this as simple as humanly possible.

Because size and weight is at a premium ($50,000/kg for launch costs), the design isn’t getting much fancier than the bare essentials.

Propellant-less propulsion would be outstanding, but we really need someone else to prove it out before we can incorporate it into the design.