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More Propellant Depot Thoughts

Jon Goff has a wrap up of the issues (mostly technical) that came up in the panel discussion last Friday in Phoenix.

As he notes, there was little discussion of what other markets we can find than DoD and NASA. The problem is that until the capability is demonstrated, it's going to be very hard to sell it to the conservative comsat industry. The nearest-term plausible private market that I can conceive of is Bigelow, if he still wants to do his lunar cruises. It would be interesting to put together a business model using Genesis modules swinging around the moon, and see if it's greater or less than projected NASA Constellation needs.


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Brock wrote:

It would be interesting to have Bigelow Stations in regular orbits (or at Lagrange points) and to use smaller 2-4 man rockets (like a space-rated Lynx or SpaceShipTwo) to catch up to them and ferry people around.

Big D wrote:

Why carry wings around if you're never going back into the atmosphere?

Think Centaur+Dragon, or somesuch (Chimera?).

Brock wrote:

Hence my use of the phrase "space rated." I just meant it need not be large like a Space Shuttle - a Lynx-sized craft would be fine. One without wings.

Jonathan Goff wrote:

You mean an orbital vehicle that could carry a comparable amount of cargo or people?


fred willett wrote:

The whole fuel depot in space thing depends on who's going to use it.
The answer is:
Nobody till it's economic.
The economic drivers are (1) lower launch costs and (2) congestion in geostationary orbits.
The second point means geosats will need to get bigger and more expensive.
The first means it becomes economic to extend the satellites life.
Launch costs (SpaceX hopefully) along with lower space station costs (Bigelow hopefully) mean you suddenly have what you need to make all sorts of interesting things happen.
Refuelling satellites. Refurbishing satellites.
That's when you need a fuel depot.
And a Habitat to do the refurbishing.
And a space tug.
And NASA will suddenly find it's sensible to refuel in space.

Robert Horning wrote:

The comment about congested GEO environment got me thinking about something: When would it make sense on a practical basis to have a manned GEO station instead of simply another bigger satellite?

For congestion in this orbit, I think the issue is already at hand, at least in terms of being able to orient parabolic antennas at the satellites. I think the current standard is 2 degrees of separation, and improvements in technology may raise that to 1 degree of separation between latitudinal "slots". There certainly is a practical limit in terms of the number active satellites that can be placed into this orbital mode and still be useful and not interfere with each other's operation.

BTW, this is also a potential sore spot in terms of international relations. Ecuador has already asserted national sovereignty over the GEO slot directly above its territory, and only the prohibitive cost of sending stuff up there has kept this from blowing up into major international incidents.

Costs to send stuff up will go down. What will be interesting is to see what happens when the full impact of that concept finally gets to some practical applications.

Paul F. Dietz wrote:

How hard is it to make electronically tracked ground antennas? If they could be made cheaply enough, we could put satellites into inclined 24 hour orbits.

Rand Simberg wrote:

we could put satellites into inclined 24 hour orbits.

That seems like just begging for high-velocity collisions, if you mean circular ones, Paul. By the way, I saw Joe Pistritto at Space Access (as I usually do).

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This page contains a single entry by Rand Simberg published on April 4, 2008 6:01 AM.

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