Friday, July 9, 2010

Once Upon A Time In Heaven: Commercial Space Takes Off

Commercial space takes off

First off, a much belated congratulations to Elon Musk and the folks at SpaceX for last month's successful test launch of the Falcon 9 vehicle. The video is as spectacular as the story of a company, that for pennies on the dollar, hbas shown a path to reducing launch costs by a whole order of magnitude. A month on, and SpaceX's work is already paying off:
Space Exploration Technologies has signed a $492 million deal to carry Iridium Communications' mobile telecommunications satellites into space starting in 2015. Space Exploration, better known as SpaceX, said Wednesday that the deal represents "the largest single commercial launch deal ever signed." Iridium provides mobile voice and data services around the globe. This comes right on the heels of SpaceX scoring a major contract with Taiwan's civilian space agency. Not quite sure what to make of Boeing's CST-100, a capsule without a launcher (for the time being) developed with assistance from the same commercial space development program as Falcon 9 and Dragon. More digging to come. NASA mission adrift? Canceling Constellation was a good thing, but not at the cost for the Vision to Explore Space. The new Administration "strategy," if you could call it that, accomplishes some good in expanding spending for aeronautics and support for commercial space, but to what end? The recent brouhaha over Administrator Bolden's Al-Jazeera interview hardly inspires confidence. Rand Simberg takes Bolden to task at Pajamas Media, while Paul Mirengoff over at Powerline has this to say: n the video below, Charles Bolden, head of NASA, tells Al Jazeera that the "foremost" task President Obama has given him is "to find a way to reach out to the Muslim world and engage much more with predominantly Muslim nations to help them feel good about their historic contribution to science, math, and engineering." Thus, NASA's primary mission is no longer to enhance American science and engineering or to explore space, but to boost the self-esteem of "predominantly Muslim nations." Exploring space didn't even make the top three things Obama wants Bolden to accomplish. The other two are "re-inspire children to want to get into science and math" and "expand our international relationships," This is more evidence, if any were needed, of Obama's lack of interest in American achievement or, indeed, American greatness. He seems to believe we've achieved enough (or perhaps too much) and that the trick now is to make nations that have achieved little for centuries feel like we couldn't have done it without them (in the video, Bolden goes on to talk about how much NASA owes the Russians and the Japanese). I draw no general conclusion about Obama's views on America's role in the world, but I agree with sentiment that internationalism is infecting American space policy to its detriment. If you absolutely have to play psychotherapist for a third of the world's population, use the State Department. Unfortunately, I fear that the Administration's disinterest in space--despite the$6 billion in increased funding over the next five years--has left NASA on autopilot, and that we're on the road to an even more embarrassing clash with reality than Constellation ended up as.

End over end in space

In 2003, the Decadal Planning Team laid down some major ground work for the long vision of VSE--exploration (and the kernel of settlement) beyond low earth orbit. One of the architectures they considered for a Mars mission was AG-NEP (Powerpoint slides), a vehicle that would tumble end over end to produce artificial gravity as its engines would constantly thrust it towards its destination. One of the problems, though, was keeping the engines aligned on course. Well, Kirk Sorenson over at SeleniaBoondocks details a solution drawing an interesting innovation from his work on tethers--the Canfield joint:
He called it a “Trio-Tristar Carpal Wrist Joint.” I thought that sounded like a real mouthful so I just called it “Canfield’s joint” and eventually everyone (except Canfield) began to call it a Canfield joint. It was kind of a crazy looking thing that you couldn’t figure out what to do with it unless you held it in your hands and started playing with it. Unfortunately, in a blog post I can’t reach out of your screen and hand you your own Canfield joint to play with, because if I could you’d figure out in a few seconds what I’m talking about, but the real magic of the Canfield joint is that you can point the joint anywhere in a hemisphere without winding up anything.

The joint has several parts. There’s the “base plate” which stays attached to whatever the joint is mounted to, like your spacecraft, and then there’s the “distal plate”, which points to whatever it is that you want to point at. There are six legs on the joint, in three units. The joint is called a “parallel structure” because there’s more than one load path for the loads to follow, and this is what gives it its potential strength. Where the legs mount to the plates is a simple revolute joint. I didn’t know what that meant so I asked Canfield and he said that it just meant that it was a simple, one-degree-of-freedom (one way to move) joint or hinge. Where the two legs come together you could have a spheric joint (a ball and socket with two degrees-of-freedom) or you could have three revolute joints in series. That’s what we usually do.

This is from the second of a series of three blog posts (1, 2, 3), which you should really read in order to fully appreciate an example of the ingenuity engineers bring to tackling problems. Bottom line, the Canfield joint solves the problem of how to keep engines properly aligned on a tumbling spaceship, and Sorenson has finally produced animations (1, 2, 3, and the grand finale) to visualize how cleverly the solution works.