Jon Goff writes about the benefits of on-orbit propellant storage and transfer. This is in fact a crucial technology to reduce in-space transportation costs, and become a truly space-faring civilization. But NASA continues to ignore it, wanting to do Apollo over again.

Rand,
They don't *entirely* ignore it. There does tend to be at least some SBIR level money for it. And some of the big boys have been willing to chip in small amounts of IR&D money for proving out various segments.

If NASA does start funding this technology more seriously, that would be great, and would help them a lot. But if they don't fund it, they can just pay a much higher premium when its available, because the commercial company running it will have much higher barriers to entry. :-)

So it isn't a 100% bad situation, but NASA is just postponing when they can benefit from the technology. Not to mention forcing themselves to waste tens of billions of dollars building big vehicles that wouldn't be needed once propellant depots are available, just because they don't want to spend the small amount of money it would take to prove out the technology.

But that's (some parts of) NASA for you.

~Jon

I think that it's fair to say that, given the trivial amount of expenditures on it, and the complete lack of planning for it in their chosen architecture, to first order, they are ignoring it.

Fair enough. Griffin doesn't actually want propellant depots before Ares I and Ares V are built, because if a depot becomes available first, it undermines the case for building Ares I and Ares V. If Ares I and Ares V get built first, it'll be a lot harder to cancel them even if that's what would make the most sense. They'll just claim that the depots are only an enhancement to Ares I/V, not a replacement. And that abandoning Ares I/V would be a waste of all the billions that went into them.

~Jon

(BTW, your content filter is obnoxious--this is the 7th time retyping this trying to figure out which word it's objecting to)

If you can tell me what string it's objecting to, I might be able to go in and fix it.

>If you can tell me what string it's objecting to, I >might be able to go in and fix it.

Isn't that sort of like asking someone to submit an e-mail request to IT support when the problem they are trying to solve is the inability to send E-mail?

That response had a very dibert twist to it.

Isn't that sort of like asking someone to submit an e-mail request to IT support when the problem they are trying to solve is the inability to send E-mail?

No. The spam filter will tell you what character string it's objecting to. Jon's problem (I assume) is that he couldn't easily figure out where the offensive string was in his comment. But if I see the string, I can go look through the list of strings to see what the problem might be. Unfortunately, it might be a regular expression of some kind, which makes it harder to track down. He could then email it to me (which is what most people do to figure out such problems. (Note: I didn't ask him to attempt to tell me in a comment...)

No. The spam filter will tell you what character string it's objecting to.

Actually, I've had your spam filter reject text as objectionable and give no indication what it was objecting to. It got so annoying that I abandoned the post rather than mess with it. It has been a while, though, so maybe it isn't so bad now.

On-orbit propellant depots are a great idea that I've been advocating for years. That, combined with a reusable space tug could greatly lower the cost for sending payloads to higher orbits and perhaps even to interplanetary trajectories. For the higher orbits, aerobraking could greatly reduce the amount of propellants needed to return the tug to the parking orbit. For interplanetary trajectories, you'd need to do a braking burn to return to the Earth and then perhaps use aerobraking to get back to the desired orbit.

There are limitations with on-orbit depots just like anything else. For one thing, your choice of depot orbit would limit who could use the depot. For example, if the depot were launched into a 28 degree inclination from the Cape, Russian launchers couldn't take advantage of your services.

I've had your spam filter reject text as objectionable and give no indication what it was objecting to.

It always tells you what string it objects to, as far as I know. You just may not have recognized what it was telling you.

> Griffin doesn't actually want propellant depots before Ares I and Ares V
> are built, because if a depot becomes available first, it undermines the
> case for building Ares I and Ares V.

It's amazing how much authority Griffin has been given without any independent oversight. NASA did not have a free hand in choosing the Apollo or Shuttle architectures. There were independent outside panels, Congressional hearings, and executive oversight. ESAS hasn't been subject to any of those things.

Is anybody working seriously on building an on-orbit storage and transfer capability? On first blush it sounds like something that would have a market if it existed--launch your satellite with low fuel to save, maneuver it to our depot, refuel, maneuver to assigned orbit; extend the life of satellites by refueling them; fuel for moon and mars missions; all the things being discussed.

It could be even better than that. Suppose you had a satellite destined for geosynch with a mass of a couple metric tons. Today, you'd have to include a sizeable upper stage capable of boosting the satellite from the initial parking orbit (if used) to a geosynch transfer orbit. Once in the proper position at apogee, a circularization and inclination change burn is performed (either by the upper stage or by a AKM inside the satellite. The upper stage then becomes space junk.

It still costs thousands of dollars per KG to put something into LEO. That goes for the upper stage used to boost the satellite into GTO, too. That means you need a booster powerful enough to launch not only the satellite but also the upper stage into orbit. The upper stage has to be more than a dumb booster in most cases. It'll need some form of TT&C and guidance system, too.

Now, suppose you had the same situation but using a refuelable space tug instead of the upper stage. The satellite owner could use a much smaller booster to put the satellite into a parking orbit (say, a Taurus instead of a Delta II). The tug rendezvous and docks with the satellite, then boosts it to GTO. If needed and sufficient delta-v capability exists, the tug could perform the apogee kick maneuver (like the old Transtage did on Titan IIIs and 34s). Once in place, the tug does a burn to drop perigee down to perhaps 120 KM. It uses carefully controlled aerobraking maneuvers to lower the apogee to the parking orbit and shift the inclination (not needed if the apogee kick wasn't performed). Once back in the parking orbit, the tug can be refueled and used again. This saves creating space junk with the upper stage, as well as reuses the rocket engine, guidance system, and related components. The potential savings for launching that satellite could be huge.

If all you're doing is launching propellant, then you can use whatever booster is cheapest that will get you to the parking orbit. You wouldn't be as concerned about reliability because you aren't risking a $100+ million dollar payload.

As I have said a number of times, the primary purpose of NASA is to stop large-scale, economical space access, and to protect its own budget and the supremacy of the USA. Large-scale space access will lead, eventually, to the loss of power for NASA and government bureaucrats, and the end of the American Imperium. And they know it; which is why the best solutions are ALWAYS rejected in favour of expensive, unreliable ones.

The rest of the world will just have to hope that someone else, with less to lose, steps into the gap.

Rand,
I had figured out which word it was objecting to right before sending the thing, but forgot to delete that little bit at the end. It was rejecting the term "0nline" (mispelled intentionally here so as not to trip the filter again). As in I was saying "when something comes 0nline".

I thought for a while it was "enhance"...

~Jon

A couple of years ago Griffin stated that an on-orbit fuel depot was something that NASA was very interested in utilizing, should it become commercially availably. He went so far as to promise over a billion dollars a year in annual contracts as long as the fuel was there in LEO for NASA to use. Regardless of whether NASA actually used it that year or not.

Bottom third of http://www.spaceref.com/news/viewsr.html?pid=18740

> A couple of years ago Griffin stated that an on-orbit fuel depot was something that NASA was very
> interested in utilizing, should it become commercially availably. He went so far as to promise over a
> billion dollars a year in annual contracts as long as the fuel was there in LEO for NASA to use.

Contract law 101: A promise is not a contract.

Politicians promise lots of things.

Did he request an appropriation? An authorization? Anything?

Does NASA have a spare $1 billion in its budget plan?