There’s an interesting dialogue over at Slate today, between Nathan Myhrvold and Gregg Easterbrook–an extension of the discussion that Gregg started with his good, albeit flawed, Time piece. It’s obvious that Gregg either didn’t read my critique (likely) or that he disagreed, though since he didn’t really respond to any of my criticisms, most likely he’s (not surprisingly, despite Glenn linking it) simply not aware of it.

I want to focus in on three of his comments:

Almost every analyst who thinks rationally about the situation comes to the same conclusion: that what’s needed is a new generation of low-cost throwaway rockets for putting payload into orbit, coupled to a small “spaceplane” carrying people only on those occasions when men and women are truly needed in space.

Well, I like to think that I’m an analyst who thinks rationally about the situation, and I do not come to that conclusion. I happen to believe that “low-cost throwaway rockets” is an oxymoron. There are smart people who disagree with me, and some of them are attempting to build such devices. Certainly we can have lower-cost throwaway rockets, but if we want to get truly low cost, for either passengers or cargo, we have to have space transports.

As to the point about “men and women being truly needed” in space, I’ll address that after the next excerpt:

Get the payloads off the shuttle and onto unmanned throwaway rockets, and astronauts will stop dying to perform humdrum tasks. The crew of Challenger died trying to deliver to orbit a data-relay satellite; the crew of Columbia died after conducting some minor experiments that an automated probe could have handled at one-tenth the price.

Sorry, Gregg, but people die doing “humdrum tasks” every day. What is so special about space that people cannot risk their lives to accomplish things of economic benefit? Why are space workers’ lives so much more valuable than, say, construction workers, or coal miners, or truck drivers?

Yes, I know, astronauts have a high value because it costs a lot to train them, but that’s just because NASA has artificially created this myth of a superhuman called an “astronaut.” In reality, a lot of the useful things that people can do in space could be blue-collar work.

If you can truly do it at lower cost (and risk) without using people, then fine–that’s the criterion on which the decision should be made–not whether or not they’re risking their lives. Shuttle is so expensive that it probably does make sense to use other vehicles to deliver payloads, but not because of the risk of astronauts’ lives. Until we clarify our flawed thinking on this issue, which is a holdover from the Cold War space program, we aren’t going to be able to come up with the right solutions.

But a shuttle replacement is exactly what’s called for, and a small spaceplane for people, plus new throwaway rockets for cargo, would fit the bill. Once such systems existed, we could think about going back to the Moon, or onward to Mars. Right now NASA isn’t even planning trips to either place, because the shuttle stands in the way.

Gregg continues to believe that there’s no private demand for human space activities, and that only NASA can take us to the Moon or Mars, or even to LEO. He’s wrong, and his proposed solution, while perhaps an improvement over Shuttle, will simply continue to put off the day that we have affordable, low-cost access to space.

We need to recognize that we have a chicken and egg problem. We will only get low costs and reliability with high activity levels, and we will only get high activity levels with vehicles designed to sustain them, at low cost (and that means not throwing them away). Gregg’s proposal does nothing to move us in that direction–it’s just a continuation of limited space activities by the government, at a slightly lower cost than the current program.