Sunday, November 28, 2010

I Guess "It's Not Junk" Is Just Too Visionary

Last week I attended a different kind of space conference. It was populated with very intelligent people who are active in doing "real" space, working payloads to get them accepted to fly on government vehicles - often up to the International Space Station - or as free flying satellites. I recorded 17 videos of the event, which I found enthralling, but I'm weird like that.

The best talk (in my opinion) was given by Dr Alice Gorman of Flinders University (Australia) about achieving an international agreement on Space Heritage. The presentation was aimed at preserving historic sites related to human spaceflight so that future generations have some physical connection with the past. This is something we do well in Australia, with "heritage listing" enforced by law. Of course, there's not that many sites that one might consider space heritage in Australia, a few radio telescopes that were used during Apollo - one that has already been heritage listed - but that's about it. The presentation went on to suggest that objects in orbit and on the surface of the Moon deserve as much respect as objects on the ground and the international agreement being sought was on how to define a "heritage site" that is off the Earth.

After the talk, some rather pointed questions were asked, and some rather pointed answers were given, then we broke for coffee. Over biscuits I stuck my head into a conversation with a PhD from Australia, another PhD from Europe and the head of a Japanese space company - his major objection was the use of the words "common heritage of all mankind" in the discussion of space heritage and all of a sudden I was feeling at home.. I expected to hear the old arguments about the United Nations Convention on the Law of the Sea, and the International Seabed Authority.. and I wasn't disappointed. What soon followed was some discussion about the private ownership of celestial bodies and yadda, yadda, yadda, you've heard all this before right?

In a way, it's nice to know that the "smart kids" are having the same conversations as the rest of us.. in a way. An argument which hasn't completely entered the standard model just yet is the suggestion that recycling satellites, spent propulsive stages and other sorts of "space junk" may be a critical part of a future space-faring civilization. No doubt, my presentation of the argument was probably a little rough, but I was surprised to lose just about everyone after the first breath. The fellow Australian was the first to break the silence suggesting that "it's going quite fast you know" as if I had just suggested the use of warp drive to catch the attention of a passing Vulcan spaceship.

Perhaps I shouldn't have labored the point, but I couldn't help myself. I started talking about the delta-v requirements of deorbiting GEO junk vs placing it into a super-synchronous graveyard orbit.. their eyes glazed over. Really? I'd just listened to four hours of ISS payload integration, the difficulties of sterilizing seeds for export, space weather detection, etc, and a little orbital mechanics is too boring?

This isn't the first time I've heard people scoff at the notion of recycling already on-orbit assets. At the New Space conference back in July a number of people said they had switched off when one of the panels started talking about it, as "they clearly don't understand orbital mechanics". It's frustrating. I don't claim to be an expert on the subject, but having actually done sufficient study (and written code) to calculate trans-lunar injection and other maneuvers, predict the trajectories of asteroids, and even change them to be more favorable for human missions, I really can't see what's so wrong with the idea of recycling valuable space assets.

If you're living in a space colony in GEO, it seems obvious that you would take whatever mass you could get for free, especially if it is highly refined solar panels and other materials. If you're living at one of the Lagrangian points you'd have to have vehicles capable of 4 km/s of delta-v and a steady supply of propellant or the means to produce it from water stocks, why wouldn't you go scavenging in the graveyard orbits for tanks and rocket nozzles to keep those vehicles operational without paying for expensive replacement parts from Earth?

Although I appreciate and respect the practicalities and even the horse trading of real space, I don't think we need to close our minds to future possibilities, as the decisions we make today, with good intentions or bad, will make that future.

4 comments:

  1. Space junk is already a problem, and it will have to be dealt with in one way or another in the coming decades. A potential group of customers would be insurance companies, paying to have clear orbits maintained for currently-operational satellites and to have spent tanks and other detritus removed from the list of potential future hazards.

    Salvage for spare parts and pressurizable volume and so forth makes sense but will require some infrastructure such as orbital propellant depots and a space tug and some kind of on-orbit warehouse. It isn't surprising that these are the sorts of technologies required for other activities beyond low earth orbit, too.

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  2. There's two types of junk that anyone cares about: stuff in LEO that is too small to track and avoid, and anything in GEO. The solution to the first is unknown. The solution to the second is to require all satellite operators to keep enough reserve fuel to provide their vehicle with 11m/s of delta-v to put it into a graveyard orbit.

    It's the objects in the graveyard orbits that I'm primarily interested in as there is likely to be quite a lot there eventually. However, some people are saying stuff like "graveyard orbits are just deferring the problem, all dead spacecraft should be deorbited" and I'm saying they're short sighted.

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  3. It is indeed short sighted. That's all stuff that doesn't have to be lifted off the earth through the atmosphere anymore. Heck, the refined aluminum alone is worth its mass in gold once it is up there.

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