Thursday, July 08, 2010

Dr Paul Spudis Continues To Baffle Me

No-one ever accused me of being subtle. I'm happy to clearly state my opinion and support it with what, I hope, is persuasive argument. As a result, subtle people tend to confuse me. That's right, along with all the other things I have accused Paul Spudis of over the last year, I'm now accusing him of being subtle: painfully subtle.

Over at Spudis's blog he rants and raves over the definition of "misconception" and manages to fit in a plug for what I guess is his position..

The purpose of lunar return under the VSE is not to collect rocks or relive past space glories. Simply put, because we can't take everything with us, humans must learn to use what we find in space to create new space faring capabilities, starting on the Moon. And our goals are not simply Mars, but everywhere – wherever human presence is needed or desired. Using the resources of the Moon (specifically, making consumables and propellant from lunar materials) enables routine access to all of space – not merely for science, but for economic and national security interests as well.

But I wouldn't dare suggest that's the entire position of Dr Paul Spudis because, as I said, he's very subtle ya know. In the comments, "Alan" asks:

So why not send a robotic ISRU demonstration first?
In the meantime build the orbital "gas stations" (1st @ LEO & 2nd @ EML-1) where, if the ISRU demonstration is successful, the LH2/LOX can flow from newly-built Lunar surface ISRU plants to EML-1 and onwards to LEO.
If Lunar ISRU does not pan out, then ship LH2/LOX from Earth to LEO and onwards to EML-1.

What is wrong with this?

Hey! That's what I said! But unlike when I asked, Spudis has responded to Alan:

Where do I argue against that?

As for propellant depots, I think that they make sense if we can supply them with propellant made from space resources, in this case, propellant derived from lunar water. If we end up launching all the propellant from Earth, then nothing is fundamentally changed, except to eliminate the need for a heavy lift launch vehicle. But you still have to lift all your supplies from the bottom of the deepest gravity well in the inner Solar System. We know that will always be a costly task — the real leverage in space transportation comes from freeing ourselves from that necessity by using local resources. That's where the biggest payoff and the largest, most significant unknowns are. Thus, that is where I think we should concentrate our research efforts.

See what I mean? He's so subtle! Paul, buddy, are you just completely unaware what Alan is saying or are you deliberately missing the point so you don't have to address it?

Here it is, as unsubtle as I can possibly make it:

Why do humans need to return to the Moon to get resources to make "consumables and propellant", if robots can be sent to do that instead?

I will continue to yell this question from the rooftops until the Moon First advocates explain why NASA should waste time building human lunar surface capability when they could be focusing their limited time and budget on developing human interplanetary cruise capability.

A capable lunar lander suitable for human use will cost as much as the heavy lift vehicle required to get it there.* On the other hand, a robotic lunar lander is under development right now, and will be launched on existing commercial boosters. In fact, a few hundred or more robotic landers could be sent to the Moon for less than the cost of human return.

ISRU demonstration followed by full scale production of "consumables and propellants" and returning them to EML-1 or even LEO is clearly a task for the robotic exploration program. Combined with the Cryogenic Propellant Storage And Transfer Flagship Technology Demonstration mission, NASA can very quickly build up in-space infrastructure for going beyond LEO.

This can completely eliminate the need for a heavy lift booster, meaning NASA could use existing commercial boosters and freeing them to focus on developing the other technologies needed to go to deep space, and develop landers which are suitable to carry humans. Perhaps even reusable landers which can be refueled on the Moon and in space.

Dr Spudis? Are you there? I'm waiting..

* Rand disagrees with me on this, see the comments below.


  1. I'm not accusing you of being subtle, Trent. I'm accusing you of being rational, thoughtful, and sometimes eloquent. Got a problem with that?

  2. Don't hold your breath, Trent. Spudis actually removed a comment I posted on his blog addressing a logical fallacy in a point he made (in my opinion, because he could not logically refute my reasoning). There was no name calling, insulting etc in my comment, only logical discussion. When I pointed this out to him via an email in response to a request he made to me for permission to post my other comments in a book he is writing, he then said he was pulling out ALL comments ever made by me from his website since I declined to let him use the other comments for the book because of the unfair deletion. If he censors comment on his own site simply because he can control it and he has no control over your site, I'd be surprised if he answers you.

  3. Rick, I got that email too and gave him permission to publish my comments for ideological reasons.. I've also had comments deleted and mentioned this to him. He says he often deletes stuff that "has been said" and he recommended I post it over on my own blog - which I've gotta say, is good advice.

    I'll delete any comment that is spam, uncivil or just off topic and have done. But hey, if you tell me I'm wrong and point out the folly of my ways I'll argue with you.. or *gasp* change my opinion.

  4. Anonymous12:03 AM

    Re: Why do humans need to return to the Moon to get resources to make "consumables and propellant", if robots can be sent to do that instead?

    You could say the same thing about asteroids or darn near anywhere else in the solar system. The R2 robots are already getting a lot of press. Perhaps our astronaut friends at JSC should have reason to be nervous.

  5. A capable lunar lander suitable for human use will cost as much as the heavy lift vehicle required to get it there.

    What is the basis of this statement? It seems nonsensical to me.

  6. As a follow up, the Project M page is fascinating and quite inspiring. I'll be showing it to my 4 year old this evening. It's stuff like this that will capture the imaginations of potential engineering students. Well done!

  7. This comment has been removed by a blog administrator.

  8. "If we end up launching all the propellant from Earth, then nothing is fundamentally changed, except to eliminate the need for a heavy lift launch vehicle."

    Is that all? I mean, that only saves NASA a mere 50 billion dollars. Hardly worth the effort then, is it?

  9. Rand, two data points: the Apollo LM cost as much as the Saturn V, and the Altair Lander was to cost as much as the Ares V.

  10. Anonymous, which is why you need to have a goal for having humans in space that makes sense. To me, that goal is "preparing to go to the future homes of humanity". Getting gas is not the goal of getting in your car, it's a stop on the way. If you can have the gas brought to you for cheaper, why would you do it manned?

  11. Ed, propellant depots are likely to cost as much as a heavy lift vehicle also.. thankfully it's completely different economics as depots are, fundamentally, reusable.

  12. I'm not sure those are good data points. In Apollo, they didn't understand the requirements very well, and they had to take every last ounce out of it due to launch vehicle constraints. They also had much more primitive computer abilities, and a huge need for them. A more robust modern architecture would allow a much less costly system (both Masten and Armadillo could do the guidance for it right now). And I'll bet that the Altair estimates were based on Apollo.

    I don't buy it.

  13. Rand, well I think the only way to lower the cost is the approach Project-M is taking now.. prototypes with incremental increasing capabilities, automated landing, reusability, etc. In other words don't waste-anything-but-time, which just supports the decision to delay massive expenditures on a human lunar lander until after interplanetary cruise capability - if you delay it long enough and work on robotic landers the need for that huge expenditure may go away. It's similar to the argument for delaying heavy lift, and is just common sense to me.

  14. I know that I'm coming to this discussion quite late so I don't know if anyone will read or reply but...

    SpaceX's Falcon 9 and Dragon capsule were designed to be man-rated to the extent of NASA published standards. So, why do we think of the manned lander as being different than the cargo lander? If possible, size the common lander to the Falcon Heavy fairing and launch a second Falcon Heavy as an RDS. Mate both in LEO before proceeding to the Moon. Being 106k to LEO vs 117k thrown means that the lander may be a bit smaller than the Eagle.

    Launch equipment, telerobots, supplies, habitats, etc first to not only establish telemining operations but to significantly retire lander risk before sending humans essentially as automatedly delivered cargo.

    The reasons to send humans to the Moon should be to establish an off-Earth, self-sustaining colony. As insurance, the value would be priceless.

    Regarding the relative cost of the manned lander, if it can be developed for the same cost as the Falcon 9 (or even 5 times that), that's certainly cheap enough for me. I would COTS it's development.