Here’s an article from the Guardian about space tourism. It’s not too bad, but I found this irritating (as I often do these sorts of things):

…even if space tourism will benefit science done in low Earth orbit, such as launching satellites, it is unlikely to help scientists reach further out into the solar system, says Kevin Fong, a leading UK expert on space medicine at University College London. “It is extremely unlikely that a successful, profitable space tourism operator would find a workable business plan for the exploration of the Moon or Mars,” he said.

Why in the world would anyone expect an “expert on space medicine” to know anything about “workable business plans”? Why is it that journalists think that they should go to scientists and researchers to learn about this stuff? They’re often the least knowledgable.

This is a paper that I wrote a couple years ago, and that I never really found a place to publish. But then, I remembered that I’m a bloggist, and have a place to publish things that no one else wants to publish. It seems like it’s a useful discussion right now, given that NASA has announced their lunar architecture plans, and things seem to be somewhat in ferment.

Continue reading Earth-Moon L1 Considerations →

Jon Goff has some very good suggestions for getting NASA on the right track.

Jeez. I have to find out via Clark Lindsey that my latest take on NewSpace in The New Atlantis is now on line.

In yesterday’s post on bypassing the moon, a commenter writes:

As long as you’re going somewhere where there are no in-situ resources to produce fuel with, you’ve got no, repeat NO advantage in terms of the amount of mass you have to put into space to get something somewhere.

Orbital refueling is the same whether it takes place next to a space-station or in the middle of nowhere. You still have to launch all your fuel from Earth. Constructing a fuel-factory base on the moon, on the other hand, means that you only have to get the payload in an agreeable orbit for the booster rockets/tanks to be launched to it from the moon.

This isn’t necessarily the case. Not all payloads are created equal. It’s conceivable that propellants could be launched more cheaply than other things (for instance, with catapults, or relatively unreliable but cheap boosters). So fueling in LEO would make sense under those conditions. In addition, you might be able to deliver propellants to GEO or EML1 much more cheaply than other payloads (e.g., by sending them on a slow tanker with a high Isp, with trip times that wouldn’t be tolerable to humans, particularly through the Van Allen belts). So there is potentially a lot of benefit to orbital fueling even in the absence of ISRU.

[Early afternoon update]

I should note that it’s also not true that “you’ve got no, repeat NO advantage in terms of the amount of mass you have to put into space to get something somewhere.”

If you can deliver propellant to a staging point (like EML1) for your return more cheaply than conventional means, you can in fact reduce the total amount of propellant required for the mission, and that must thus be delivered to space. That’s because it takes propellant to move propellant. If you deliver your return propellant as part of the total lunar insertion payload, it costs just as much, in terms of injection propellant requirements, as a pound of anything else. But if you can get it out there using low-thrust systems or (as Jon Goff suggests in comments) by Weak Stability Boundary trajectories, you can get the propellant there with a lot less propellant. There are really huge payoffs to the ability to store and transfer propellants on orbit, regardless of the cost of launch from earth.