…on the high seas. Though he doesn’t discuss it explicitly, Chris Borgen makes another case for why we need to get off the planet.
Category Archives: Space
Panacea
One of the more annoying things that I find in commentary on space policy is the assumption that there is One True Way to get off the planet, and that working on anything else (particularly chemical rockets) is a waste of time and money. Often it’s space elevators, but here’s another case in point: an Orion fan (the original Orion, not the current Apollo crew module on steroids):
Nuclear power is still the only thing that’s going to allow us to get large amounts of mass into Earth orbit and beyond. Nothing else has enough specific impulse to do the job.
While nuclear-pulse propulsion may be an interesting technology for in-space transportation, where the radiation level is pretty high to start with, it was never going to be used for earth-to-orbit transportation. One does not have to be a luddite to believe this. I’m all in favor of getting access to orbit as low cost as possible, as soon as possible, but I think that the notion of using Orion for this is nuts (and not just for the radiation and atmospheric contamination issues–consider the EMP…). I highly respect Professor Dyson and Jerry Pournelle as well, but that doesn’t mean that there aren’t some major technical issues in getting such a system practical and operational. If such a system is ever built and tested, it will be built and tested in space, after we’ve come up with other ways of getting large amounts of mass into orbit, affordably. And I’m quite confident that if and when we do this, it will (at least initially) be with chemical rockets.
Part of the misunderstanding is revealed in the second sentence. The assumption is made that the reason costs of getting into space are high is due to performance, and particularly a specific performance parameter–specific impulse. For those unaware, this is basically a measure of a rocket’s fuel economy. The higher the Isp, the less propellant is required to provide a given amount of thrust over a given time period.
But there is no equation in vehicle design or operations that correlates cost with Isp. If Isp were the problem, one would expect propellant costs to be a high percentage of launch costs. But they’re not. Typically, propellant costs are on the order of a percent of the total launch costs. Yes, requiring fewer pounds of propellant means that the vehicle can be smaller, which reduces manufacturing and operations costs, but it still doesn’t account for the high costs.
Chemical rockets are perfectly adequate for affordable launch–their specific impulse is not a problem. As an example of why there’s a lot more to rocket science than Isp, consider that some of the more promising concepts (LOX/hydrocarbon) actually have lower specific impulse than so-called “high performance” propellants (LOX/LH2). Why? Because liquid hydrogen is so fluffy (the opposite of “dense”) that the tank sizes get large, increasing vehicle dry mass and atmospheric drag. For instance, the Shuttle external tank carries six pounds of LOX for each pound of hydrogen, but the LOX is all carried in a little tank at the top, and most of the ET that you see contains liquid hydrogen.
As I’ve noted many times before, there are two key elements to affordable launch using chemical rockets. Fly a lot, and don’t throw the vehicle away. Despite the mythology about the Shuttle, we’ve never actually done this in a program. It seems unlikely that NASA ever will, but fortunately, private enterprise is finally stepping up to the plate.
NewSpace 2008 Blogging
It looks like Clark Lindsey now has an internet connection, and he’s got a lot of posts up with descriptions of the sessions yesterday and today. There are permalinks, but a bunch of them, so for now, just keep scrolling.
So far, I don’t see a lot of news coming out of the conference, other than the CATS Coalition announcement.
An Interview With Elon Musk
“I wasn’t born in America – but I got here as fast as I could.”
That’s an American.
NewSpace 2008
Clark Lindsey apparently had trouble getting an internet connection until now, but he’s started blogging the conference. Which I could have attended.
A New Toy For Rich People
A submersible speedboat that can dive to twelve hundred feet. If there’s a market for this, at a few million a pop, I’ll bet that XCOR will be able so sell a few Lynx’s to private owners.
A Pioneer, Not Forgotten
Here’s the obit at the WaPo for Len Cormier.
As a staffer with the Academy in 1957, Mr. Cormier was in attendance at the International Geophysical Year proceedings when the Soviets surprised the world with the launch of Sputnik.
The event made a tremendous impression on him, his family said. He decided then to pursue better access to space through affordable, reusable space vehicles.
He was an early visionary. Others will have to pick up his torch now.
Fortunately, a lot of other people now recognize the need:
The National Coalition for CATS, working with leading figures across the space community, will collaborate over the next twelve weeks to develop a “National Declaration for Cheap and reliable Access to Space (CATS).” The CEOs of non-profit and for-profit companies will be invited to sign the Declaration, and will deliver this declaration to the next President of the U.S. after the November election.
Unfortunately, I won’t be able to attend NewSpace, which starts tomorrow in Washington, and where this will be announced, due to financial constraints. It will be the first conference I’ve missed in a while.
Thirty-Nine Years Ago
On July 16th, 1969, the largest rocket ever built thundered off the launch pad at Cape Canaveral, delivering three men and the equipment and supplies they would need to land two of them on the moon and return the three of them safely to earth, fulfilling the national goal declared eight years earlier. The anniversary of the landing is this coming Sunday.
NASA Employee Bleg
Can anyone at the agency go on the record (with PAO permission) and tell me why they think that sending ISS to the moon is a bad idea? I’m working on a piece (I think it’s a bad idea, myself, and have some better ones). Email me at the upper-left email.
More Fear Mongering
Mike Griffin again disquisites on the Yellow Peril.
Well, actually he doesn’t. Here’s all he says (unless there’s some elaboration to which the BBC is privy, but we are not):
Speaking to the BBC News website during a visit to London, Dr Griffin said: “Certainly it is possible that if China wants to put people on the Moon, and if it wishes to do so before the United States, it certainly can. As a matter of technical capability, it absolutely can.”
What does that mean? If he means that if China made it as much of a priority as we did during Apollo, and if we continue on our own disastrous plans, that they could reverse engineer what we did and put some Taikonauts on the moon before NASA lands astronauts, sure.
But how likely is that? And even if it happened, what’s the big deal? We were first on the moon, they were second. Big whoop. There’s no way on their current technological trajectory to do it in any sustainable way, and even if they did, there’s nothing they could realistically do there that would constitute a threat to us, either in terms of national security, or our own ability to do things there on our own pace.
My take?
It is extremely unlikely–the Chinese are not fools. They know how much it will cost to do a manned lunar mission, and it’s not a high priority, particularly when their economy is potentially a house of cards (something not made better by the current energy prices, which will result in either a curtailing of their fuel subsidies, or a decline in economic growth, or both). If and when they are serious about going to the moon, it will be quite obvious, and we’ll have plenty of time to do something about it if we think that it’s actually a problem.
But Mike apparently thinks that he’ll have a better chance of getting increased funding for Apollo on Steroids if he can frighten uninformed people about the Chinese taking over the moon.