Josh Hopkins has a thoughtful article over at The Space Review on the issues that must be addressed by proponents of propellant depots. I may have a response a little later, but I would note that Boeing has done a lot of work on the concept, and may have answers to some of the questions. In any event, we could have resolved them with a tiny fraction of the money that we just pissed away on Ares over the past four years.
[Update early afternoon]
In comments over there, Jon Goff makes one of the points that I would have had I gotten around to it (we’re getting ready to move, and writing SBIRs among other things, around here). It’s worth repeating:
2-Regarding launch costs: I think most depot researchers, like myself, would agree that if the cost for propellant delivery were truly likely to be in the $30-60kg range, that depots weren’t likely to make sense. However, is using delivery of cargo to a manned space station, where the cargo carriers themselves have to function as pressurized space station modules, really that realistic of a starting point for estimating the cost of propellant delivery to a likely unmanned depot? I know that that was probably the easiest way to do the analysis, since those numbers are available…but aren’t we setting up a strawman here? First you pick the obviously most expensive route (having the tankers be fully-functional prox-ops vehicles), and then pick one of the most expensive possible cases of such vehicles–vehicles designed to interface with a manned space station.
This is a typical tactic of opponents of an idea — to pick a worst case, and sort of imply that it’s a best one. It is not a realistic assumption, and was one of the flaws that jumped out at me at the time.
Another one is the concern about departure windows. Yes, launching from earth gives you more flexibility, but so what? If there are multiple opportunities per month from orbit (and there are, depending on how much you want to pay in delta vee for wider windows), then it doesn’t help you much to be able to launch more often from earth when your HLV architecture won’t be able to afford to launch more than a few times a year, even using the cost estimates of its most ardent proponents.
[Tuesday morning update]
Clark Lindsey has further thoughts.
Well, it’s not gone, but it certainly has gone out of fashion compared to when I was a kid. How many kids work on their own cars these days? Though I would note that just changing a head gasket is not equivalent to rebuilding the whole engine.
I think that this is part and parcel of the whole academic bubble, which continues to inflate beyond economic reason. Particularly in today’s economy, people should realize that plumbing can’t be outsourced.
[Update about noon]
Speaking of the upcoming pop of the education bubble, some schools are now not allowing parents to see their children’s grades in college. How many parents are going to put up with that and continue to pay tuition to such an institution? The notion of “treating students as adults” works fine for students who are actually adults. But adults pay their own way. There’s a lot more to being an adult than simply surviving long enough to reach the age of majority.
President Obama’s report card:
Subject: History Grade: F Comment: Among Barry’s weakest subjects. He experiences great difficulty identifying his centuries and has very little grasp of historical facts and events. As well, he shows a distinct aversion to diligent research. His instructor was particularly dismayed by his inability to tally the number of states in the union.
Subject: Political Science Grade: F Comment: A field of study which Barry would do well to avoid in the future. Fundamental ideas in statecraft appear alien to him. His romantic view of the world and his assumption of personal infallibility breed complacency rather than proficiency.
Subject: Economics Grade: F Comment: Barry shows no understanding of economic theory and seems incapable of mastering the complexities of the discipline. His class projects have advocated solutions to topic problems which would lead to disastrous results in the application.
Subject: Self-Esteem Grade: A++ Comment: A course only recently added to the syllabus. Barry led his cohort group by a wide margin and even exceeded the degree of instructor expertise.
Sounds like there’s room for improvement. But unfortunately, he’s the
Second-Amendment-loathing mayor attacked with a lead pipe.
But was it in the library, or the ball room? And by Colonel Mustard, or Miss Scarlett?
…isn’t enough. Thoughts from Cato and Reason.
I have some thoughts this morning, over at Pajamas Media.
Obamacare, that is. Not that Obama cares. Have to break eggs to make an omelette, doncha know?
“…would give up his brain for a decent size.”
That was the subject of one of the myriad spam emails I get encouraging me to enhance…something or other. I have to believe that women get them, too.
Anyone who responds to such idiocy had no brain to give up in the first place. It’s as stupid as the ones that tell me that no one can resist buying a new watch. Watch me.
I hadn’t realized that Jorge Frank had teamed up with Dennis Jenkins to put out a new book on Apollo, with lots of photos. Looks like a must-have for an Apollophile’s book shelf.
By the way, thanks to whichever of my readers bought a Kindle at my Amazon store. I can always use the extra income.
Jim Oberg has a good piece today. It’s just not as easy as the Barsoomophiles want to believe. That doesn’t mean that it shouldn’t be an ultimate goal, but we need to put first things first — reducing the costs of launch, developing critical technologies (particularly propellant handing and manufacturing from ISRU) and preliminary scouting to the moons before it will be practical to put people on the surface.
It’s official: NASA is a jobs program. Not that that’s news…
“…critical skills”, “industrial base”, and “workforce retention” have been frequently-mentioned items in the committee’s deliberations to date, so I suppose I should have seen this coming, but it’s still one of the starkest illustrations I’ve encountered why government programs and NASA in particular will never accomplish the goal of making humans a spacefaring species.
Fortunately, there are alternate paths.