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« Hold Mah Beer... | Main | I Could Write A Long Essay On This »

Why HLVs?

OK, my question to Dr. Stanley is, if it's a good idea for Mars, why isn't it a good idea for the moon?

"If you refilled the EDS in orbit [using commercial LEO fuel depots] it could act as the MTV," says Georgia Institute of Technology aerospace professor Douglas Stanley, manager of the November 2005 NASA exploration systems architecture study (ESAS).
Posted by Rand Simberg at August 15, 2006 01:39 PM
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Listed below are links to weblogs that reference this post from Transterrestrial Musings.
Refueling EDS's in Orbit?
Excerpt: Rand asks if on-orbit refueling is a good alternative to HLVs for Mars, why not for the Moon too?
Weblog: Selenian Boondocks
Tracked: August 15, 2006 09:59 PM
Comments

The answer to your question is that it is and will be used to argument the capability being developed.

Posted by Mark R Whittington at August 15, 2006 01:55 PM

You must have pretty good clairvoyance, Mark, because one would certainly not be able to rationally discern that from any of NASA's stated plans (e.g., they plan to build an HLV capable of doing a lunar mission in a single launch). Can you give me the name of your psychic?

Posted by Rand Simberg at August 15, 2006 01:58 PM

What fuels are available at the LEO fuel depots, and how much storage (capacity) is available? If the commercial market only supports a set of "standard hypergols" that can be stored in useful quantities over a sufficiently long term to allow cost-effective re-supply, for example, the notion of pulling up in anything like the EDS and saying "fill 'er up" is ridiculous.

Posted by snellenr at August 15, 2006 03:52 PM

"Can you give me the name of your psychic?"

Mike Griffin, who mentioned the idea in a speech some months ago.

Posted by Mark R Whittington at August 15, 2006 03:57 PM


> Mike Griffin, who mentioned the idea in a speech some months ago.

No, Mark, Griffin did not say he was cancelling SD-HLV and using orbital refueling instead.

What he said was that he would "like" to use orbital refueling "if it was available." That statement's pretty meaningless, however, since his ESAS architecture is not designed to take advantage of orbital refueling.

It's no great surprise that you don't understand the difference. :-)


Posted by Edward Wright at August 15, 2006 07:38 PM

The article linked in the post discusses refuleing Ares V on orbit. Not needed for the Moon but very useful for Mars.

Posted by Bill White at August 16, 2006 05:05 AM

Stanley actually said on nasaspaceflight.com something like that he prefers orbital refuelling and reusable launchers, even a reusable lsam. In the long term. But the produced ESAS architechture is the best possible with the current time and money constraints.

Posted by mz at August 16, 2006 05:12 AM


> Stanley actually said on nasaspaceflight.com something like that
> he prefers orbital refuelling and reusable launchers, even a
> reusable lsam. In the long term.

Okay, this is Bill White's favorite dog bone. Just "make" the LSAM reusable. In the long term.

Please explain how you would do that. Leaving aside the fact that LSAM will probably use toxic propellants, remember that it is a two-stage vehicle. Every time an LSAM lands and takes off again, it will leave the descent stage on the Moon. How would you turn a two-stage system expendable lander into a one-stage reusable? Why would anyone expect such a kuldge to be cheaper than designing a new reusable lander from scratch? And if the goal is to have a reusable lander "in the long term," why not design and build it now?

Another question is how NASA would *maintain* a reusable lander in space (or on the Moon) unless space transportation costs are reduced. If it costs $10,000 a pound to send spare parts to the Moon (and even more to send mechanics), it's going to be hard to maintain anything.

> But the produced ESAS architechture is the best possible with the
> current time and money constraints.

If that's true, he must have chosen a very poor set of options to compare it against.

Posted by Edward Wright at August 16, 2006 12:31 PM

Edward is, as usual, making things up and missing the point. On orbit refueling will extend the capabilities of EDS and will not only be useful for Mars but will increase the amount of payload that can be launched to the Moon, which will be very useful when people are living there permenently.

Posted by Mark R. Whittington at August 16, 2006 01:08 PM

And if the goal is to have a reusable lander "in the long term," why not design and build it now?

Absolutely. Hopefully, a successful October in Las Cruces (Lunar Lander challenge) will help on this point.

The LSAM should be single stage LOX & ?? from the very beginning. A handful of RL-10s may be sufficient for this r-LSAM although better choices from Masten or Armadillo et. al. will surely exist soon enough.

LOX and ?? - - > H2? CH4? Some alcohol or another? I dunno.

Lunar LOX extraction should commence as soon as possible as a high priority item. And remember that some of the combustion products from every landing and launch (H2O and C02) will accumulate on the regolith underneath the landing pad.

If we intend to sift regolith for He3, why not sift for H2O and CO2 to make methane, while we are at it?

= = =

EML-1 and EML-2 strike me as the only logical places to park an r-LSAM between uses.

Posted by Bill White at August 16, 2006 01:12 PM


> On orbit refueling will extend the capabilities of EDS

Really? The EDS stage is designed for on-orbit refueling? Who knew?

Do you have any evidence to support that statement? Or is this just wild unsubstantiated claim number 317?

> which will be very useful when people are living there permenently.

So, now you think NASA is going to have people living on the Moon permanently?

You're losing it, Mark, completely.

Posted by Edward Wright at August 16, 2006 03:23 PM

Sigh, why do some people have to take it so flamey.

You can read up the "Ask dr. Stanley" threads from nasaspaceflight yourself. I think some people misunderstood some points. He just said that the reusable things (like launchers) were intuitively good stuff in his opinion, the study probably outruled them out quite early because of time and money constraints. But he personally still feels they are the way to go in the long run. Yes, redesign a lot from scratch I guess.

Posted by mz at August 16, 2006 03:36 PM


> He just said that the reusable things (like launchers) were intuitively
> good stuff in his opinion, the study probably outruled them out quite early
> because of time and money constraints.

No, the quote from Dr. Stanley was not talking about reusable launchers. It was talking about orbital refueling of the Earth Departure Stage, which does not require reusable launchers (although it would certainly benefit from them).

Saying he "outruled" orbital refueling because of time and money constraints makes no sense, since he proposed a far more expensive architecture. Unless the constraint was to spend as much time and money as possible.

Posted by Edward Wright at August 16, 2006 04:45 PM

Uh, the "quote" was talking about reusable launchers too. I don't know why you say otherwise as everyone can scroll up and see for themselves.

Posted by mz at August 16, 2006 04:58 PM


> Uh, the "quote" was talking about reusable launchers too. I don't
> know why you say otherwise

Because none of the words in the quote look anything like "reusable launcher":

-> "If you refilled the EDS in orbit [using commercial LEO fuel depots]
-> it could act as the MTV," says Georgia Institute of Technology
-> aerospace professor Douglas Stanley, manager of the November 2005 NASA exploration systems architecture study (ESAS).

And if you follow the link to the article, none of the words there look like it, either.

In fact, the article specifically states that the depot might be filled by COTS vehicles. Most of the COTS proposals do not involve reusable launchers, and I presume Dr. Stanley knows that. So, inferring that he is talking about reusable launchers would be most illogical.

Posted by Edward Wright at August 16, 2006 05:37 PM

Oh, you mean the Flight article. But I was discussing what he said on nasaspaceflight.com months ago (informally of course). If I remember correctly. I think there he mentioned reusable launchers too, at which point orbital fuel depots become even more useful.

Anyway, if he thinks it is possible, why he didn't think all the parts could as well be launched separately with smaller launchers and refueled from a depot. You can go to the moon on a few sticks. (and a bunch of tankers) :)

Posted by mz at August 17, 2006 04:25 PM


> Anyway, if he thinks it is possible, why he didn't think all the parts
> could as well be launched separately with smaller launchers and refueled
> from a depot. You can go to the moon on a few sticks. (and a bunch of tankers) :)

Yes, exactly. Or a few Deltas or Atlases.

Posted by Edward Wright at August 17, 2006 05:04 PM


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