There's a new Planetary Society contest: "Are We There Yet? -- Measuring Stardust's Cosmic Journey." How far do you think Stardust will have traveled to get to Tempel 1? Guess here and get a chance to win a cool T-shirt!
I'm excited to offer this new contest, and want to explain where it came from. Six years ago, the Planetary Society ran a contest for the Deep Impact mission in which we invited people to guess the diameter of the crater that it would leave on Tempel 1, which I organized. We collected lots of entries and then ran into a big problem, which was that the spacecraft never saw the crater through all the dust. The science team could only estimate (if I recall correctly, by working backward from the volume of the ejecta that was thrown out, and the shape of the ejecta curtain) that the crater was most likely between 100 and 250 meters in diameter. Which was still a pretty big range; of the more than 7,000 people who entered the contest, 1,865 of them had guessed a number within that range. We held a random drawing from among those people and sent prizes to three of them. Which didn't satisfy many people, certainly not me. But what could we do?
NASA / JPL / UMD
Stardust was the first spacecraft to return a cometary sample and extraterrestrial material to Earth from outside the orbit of the Moon. In 2004, Stardust made a close flyby of comet 81P/Wild (Wild 2), collecting comet and interstellar dust in a substance called aerogel.
So, with Stardust returning to Tempel 1, I of course wanted a second chance at that contest and I think a lot of other people do too. The problem is that Stardust isn't guaranteed to see the crater. If the astronomers don't have the right rotation rate pinned down, the crater might not be visible. Even if it is visible, the passage through perihelion could have produced changes in the shape of the crater as the comet outgassed -- the crater should have exposed fresh ice, which would presumably be pretty active as the comet approached the Sun. Even if it is visible, and hasn't changed much, the science team wouldn't be able to tell me right away what the exact diameter is; it'll depend on its orientation with respect to the camera, and the shape of Tempel 1, and the final estimate from the navigators of how close they got to the comet, etc. etc.; and the crater size will be one of the significant results of the flyby so they'll want to hold their number close to the vest until they get it published. And, of course, there's always the possibility that Stardust (which is, I'm told, not an easy spacecraft to fly) will suffer some problem that'll prevent it from taking pictures even if everything else goes well.
The punch line is that we are running a contest for the Stardust flyby of Tempel 1 but not to guess the crater diameter (though I certainly can't stop you from Tweeting me crater diameter guesses). Instead, they came up with a contest that we can definitely close on February 15 no matter what happens:
NASA's Stardust spacecraft will fly past Comet Tempel 1 on February 15 (4:00 UTC), which will be February 14 here in the United States. Stardust left Earth 12 years ago, an odyssey that has carried it past a comet, back to Earth, and on a course to a second comet under a new name ? Stardust-NExT (New Exploration of Tempel 1). Because the spacecraft is carrying on board the names of more than a million inhabitants of Earth, the Planetary Society named its new Stardust contest with long road trips in mind: "Are We There Yet? -- Measuring Stardust's Cosmic Journey."
"Are We There Yet? -- Measuring Stardust's Cosmic Journey" invites people to guess how far Stardust and the names will have traveled from launch until closest approach to Tempel 1. The Planetary Society will accept guesses until February 15 at 4:00 UTC, just before the planned flyby. Entries will also be accepted on Twitter, using the hashtag #stardustcontest.
The ten closest guesses will win. Along with fame and glory, each winner will receive a Planetary Society Stardust t-shirt and a goodie bag from the Stardust-NExT mission. Anyone of any age in any country may enter except the staff and family members of the Planetary Society and the Stardust-NExT mission. See contest rules for complete details.
"We hope this contest will help people everywhere appreciate the remarkable maneuvers engineers came up with for this second visit to Tempel 1," said Bill Nye, Executive Director of the Planetary Society. "The Stardust-NExT spacecraft has taken quite a journey ? 12 years so far."
Stardust-NExT is a low-cost mission that will expand the investigation of Comet Tempel 1 initiated by NASA's Deep Impact spacecraft. The Planetary Society involved people worldwide with the Stardust mission in two different ways. Stardust@home invited participants to help find interstellar dust particles collected by the spacecraft, by examining "movies" of the aerogel collector posted on a website. The Planetary Society also sent the names of all its members at the time of launch aboard Stardust. (By the way, I don't discourage insiders from entering the contest; you just don't get to win free T-shirts.)