At Astronautix, it says that:

The propellant combinations WFNA/ JP-4 and later IRFNA/JP-4 were the first storable systems given serious consideration in the United States. Problems which caused the abandoning of these propellants were the absence of reliable hypergolic ignition and unstable combustion. IRFNA/UDMH and IRFNA/JP-X finally did prove satisfactory.

By the late 1950’s it was apparent that N2O4 by itself was a better oxidiser. Therefore nitric acid was almost entirely replaced by pure N2O4 in storable liquid fuel rocket engines developed after 1960.

Apparently it was so apparent that they have no need to explain why it was so apparent. What was the benefit of going from nitric acid to tetroxide for hypergolics? What was “better” about it? Anyone know?

I’m back in DC, and busy, so I don’t know how much posting there will be, but I did want to note on reconsideration one problem with the New York Times editorial advocating ending Shuttle and ISS. Jorge Frank, over at sci.space.policy, pointed out last night that they seem to want to eat their cake and have it too.

They call for an end to any more ISS missions, but want a Hubble repair. Well, if they do that, they should realize that a) they won’t get the forty billion in savings that their editorial states, and b) that Hubble repair mission will cost at least six billion or so (more than launching multiple replacement telescopes). This is because the soonest that a Hubble repair mission could be mounted is probably about a year and a half from now. That means that the infrastructure to support the Shuttle would have to be kept in place for another year and a half. It also means that, since there would be no ISS missions against which to charge these fixed costs, these would all be debited against the Hubble mission (the only reason that the system remained in place, accruing those costs).

So they can phase out Shuttle and ISS, but it’s hard to then make an argument for Hubble. And if they’re going to keep it alive for Hubble, then they might as well figure out some way to maximize the utility of it for getting station as far toward completion as possible while the system is still operating. In the latter scenario, it just means figuring out the minimum number of flights that should be done with Shuttle, and how to manage without it for the rest. Which (almost surely not coincidentally) is exactly what Mike Griffin’s NASA is planning to do.

[Update a few minutes later]

Mark Whittington disagrees with me. Well, actually, as he often does, he disagrees with a strawman argument he pretends is me:

…the fact of the matter is that the first people to return to the Moon and then go to Mars will be employees of some government (hopefully including the American one). The private sector will have a very big role, especially once people start living off the planet in significant numbers. But big bad government will also have a role in opening up the high frontier, just as it has with every other frontier. That’s the truth, supported by history and common sense, whether one wants to believe it or not.

their role would be, and I don’t think that it will be anywhere near as large as most conventional thinking about the space program would have it. The issue is not whether or not government will be involved, but which branches of it, and how. The monocultures that NASA’s manned space centers tend to produce will continue, I think, to be evolutionary dead ends (just as Shuttle and ISS have turned out to be). But because they generate so many jobs, they will continue until (like Shuttle and ISS) they become untenable in the face of clear private (and other government, such as the DoD) alternatives.

[Update again]

Now Mark trots out a new straw horse in response:

I must admit to a little confusion. What other government agency besides NASA would take the lead government role in space exploration?

I expect NASA (until costs come down quite a bit) to continue to lead “space exploration” (though much of that will be done out of Pasadena, and will be unmanned). But of course, until now, I said nothing about space exploration. I thought we were talking about humanity moving out into space, which is much less about space exploration than space development. And space development will occur with the help (and hindrance, and connivance) of a number of government agencies, including the FAA, the DoD (including DARPA), DoE, and perhaps even Commerce. NASA building small and expensive capsules launched on equally-expensive heavy-lift expendables from Cape Canaveral may provide some entertainment to the masses for a while, but it will have little to do, ultimately, with the development of space, any more than Shuttle and ISS have.

I went to read the NYT editorial that Sam pointed out, in which they advocate cancelling Shuttle and ISS. I assumed that if it was the right recommendation, it was probably for the wrong reasons, given their history, but I actually could find very little with which to disagree. Really, the only reason to keep Space Station Albatross going has been the diplomatic one. Unfortunately, that’s probably been enough, given that the administration has been loathe to give its enemies one more club with which to bash them over our relations with our “allies.” But as the Times points out, even they would probably be relieved to get out from under this white elephant themselves (though they’d know doubt spout crocodile tears about this latest unforgiveable breach in international relations).

Some are complaining in Sam’s post that the only reason that the Times is doing this is because they hate “the manned space program.” Well, if they do, it’s partly because there’s a lot to hate there, and little to love at this point. But they also have to reconcile this charge with the Times’ argument that killing off these deadweight programs could accelerate outward human exploration. In fact, usually the argument from NASA manned spaceflight enthusiasts whenever it’s suggested that we end the Shuttle (and/or ISS) program is that it will toll the end of manned spaceflight in the US, and that a bird in the hand is better than two in the…errrr…Bush.

That argument may have had some resonance prior to January 14th, 2004, when the only human-in-space policy was Shuttle and ISS, but it doesn’t any longer. Yes, some new president could come in and cancel the exploration initiative in 2008, and if that happens, it would be impossible to resurrect the Shuttle and station if they’re ended now. But barring some major political earthquake, I find that scenario unlikely. For better or worse, the public does seem to have some intrinsic desire to see human spaceflight at NASA continue, and I don’t think that it’s in the cards politically to end it. In fact, with the new program having been bought into by both the administration and Congress, I’d think that NASA manned space program proponents would be eager to shed these deadweight programs so they can get on to the more exciting activities of returning to the Moon and going on to Mars. Unless, of course, they’re getting their paychecks from the status quo…

And of course, this all ignores the vast potential for much more interesting private human spaceflight activities, which I’m quite confident will make almost everything that NASA is doing in this area irrelevant by the end of the decade.

Anyway, as I said, I could find little in the editorial with which to disagree. I’ll toss in my concurrence as well, though from a long-term policy standpoint, I don’t really think that it makes much difference to our future in space whether we end these dinosaurs now or later. Either way, humanity’s expansion into the cosmos will have little to do with anything happening at JSC, Marshall and the Cape now. They did some noble and needed pioneering things there forty years ago, but I’m afraid that when it comes to the future, they continue to represent the past.