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The Planetary Society BlogBy Emily LakdawallaThe Greatest Mission You've Never Heard AboutSep. 25, 2006 | 11:17 PDT | 18:17 UTC
by David Seal
Some years ago, before I returned to Cassini to be the Mission Planner, I had the honor of working on a great project called the Shuttle Radar Topography Mission (SRTM), and it was one of the most amazing professional experiences of my career. What? Shuttle, you say? Don't you work at the Jet Propulsion Laboratory? What does JPL have to do with the Space Shuttle? It's a reasonable question.. but while it might seem like JPL does mostly robotic solar system exploration and the Johnson Space Center focuses on manned space flight - little overlap except for mutual respect for each others' work - our two centers have had a long and very rewarding relationship. JPL's Ulysses and Galileo spacecraft were launched aboard the Space Shuttle; JPL built the Wide Field and Planetary Camera capturing pictures on board the Hubble Space Telescope, also orbited by the Shuttle; and the Shuttle carried imaging radar to study the Earth on no fewer than four missions (SRTM being the most recent). The first of these missions was actually the very first payload the Shuttle carried, aboard STS-2 in 1981. Ten additional JPL experiments of varying scale also flew on the Shuttle from 1981 to 1998. SRTM flew on STS-99 in February of 2000. (We were nearly STS-100, which would have been a curious milestone, but they reshuffled some of the numbers for reasons I can't recall; though it's possible they wanted 100 for a space station mission. It's an arbitrary distinction so I didn't really care. 99 was pretty cool anyway.)
Earth, I say? The Earth?? This boring planet? How is this exciting? Well, to begin with, let's back up. Did I really say sixty-meter boom? Extending out from the Shuttle? Sticking out of the payload bay. Starts in a can, goes out 200 feet, Shuttle flies around for ten days, it doesn't break and wrap around the orbiter, then it fits nicely back in the can. Really? Absolutely! That's the length between antennas we needed to do proper interferometry. And just think about how big sixty meters is. We were the largest fixed structure ever deployed in space. (The Patriot's offense rushed for less distance on Sunday. Sigh....) And the can it started and ended in was only 10 feet long - that's like shrinking Shaq to just over 4 inches tall. You can imagine the concern we got from some of the engineers and safety personnel at Johnson when we pitched them our crazy idea. If you or your kid has a Shuttle model, wrap a slinky around it a couple of times and you can picture some of the worst-case scenarios that went through their minds. But can you blame them, when the lives of astronauts and the future of NASA are possibly on the line? Needless to say, we were incredibly safe and successful or clearly I wouldn't be talking about SRTM to you.
Another plus for me was the technical discussions full of passion that happened day after day during the development phase of the project. I remember fondly countless meetings and email threads spent arguing with the other key engineers over how best to do this and that. Our conversations crackled with energy. Sometimes I think the powers that be can place too much emphasis on calmness and compromise and diplomacy. Often when engineers are wrestling with an issue, were all tempted to step in and work out an even solution that makes everyone equally unhappy. But here's a secret: sometimes the crazy person tearing their hair out scribbling on the white board making their case with elevated audio is really on to something. Sometime compromise isn't the best solution. Passion is what drives exploration, and it was crucial that our managers let our kind of energetic arguments play themselves out, and they did. I also think we benefited from flying under the Radar (pun entirely intended) to a certain extent. We weren't landing rovers on Mars or hurling schoolbus-sized behemoths through the rings of Saturn; we were just this little Earth mission that was an extension of three others that had already flown with success. Don't mind us.. just passing through.. we arent the droids youre looking for. And so we were left alone to form ourselves into a small, perfectly-staffed team of highly skilled engineers with just the right amount of highly skilled managers and just enough reviews from JPL and NASA HQ to do the impossible in a very short amount of time. So what did SRTM get? Wrong question. The accurate question is, what did you get. Well, you got a continuous, high-resolution, self-consistent map of the entire land mass of the Earth (under 60 degrees latitude, which was as high as we could reach). And what can you do with that? Here are just a few examples:
Oh and anyone can go get the data for their own application. It's an information set for the ages.
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I live in the Uk ( under 60 deg/ lat) I used the SRTM data today in my GPS as a contour map to do a bit of hiking up the local hills. Every time I look at that contour map I acknowledge the staggering mission and engineering that was behind it.
Thank you
S.