Temple 1: See you again with a comet

Flyby of the space probe Stardust-NeXT on the comet of the Deep Impact mission

Stardust approaching the comet Temple-1 - Artistic Illustration © NASA
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For the second time in its long career, the space probe "Stardust" will approach a comet up to 200 kilometers. In the early morning hours of February 15, the probe passes through the comet Temple-1, offering astronomers two unique opportunities: First, a new look at the impact crater produced by the 2006 Deep Impact mission. On the other hand, the first chance to examine the changes in the cometary surface before and after a solar orbit.

The comet Temple-1 has a ready story behind it - and part of it was caused by humans. Because in 2005, the comet received a visit from the NASA spacecraft "Deep Impact". This not only made numerous close-ups of the comet, she also had a so-called "impactor" in the luggage - a good 370 kilograms impact body. This catapulted them onto the surface of the comet, with the aim, among other things, of ejecting material from layers deeper below the surface, thus revealing more about the density and composition of the cometary nucleus, but also about the change in the surface.

First clear pictures of the Deep Impact impact crater

But in the end, so much dust was whirled up during the impact that the impact crater was completely hidden. The dust made it impossible for the camera of the Deep Impact probe to observe the point of impact more closely. Now, however, the second visit of the comet by a space probe, this time "Stardust-NexT" offers a new opportunity here. The Stardust probe passes the comet at about 200 kilometers from the surface of the cometary core on Valentine's Day, after the American and early morning of February 15 after our time.

"The dust has settled in the meantime, so we can see the crater and its size, if we are facing the right side of the comet, " explains Joe Veverka, scientific director of the Stardust NexT mission. "That would answer some key questions. For example, whether the surface of a comet is hard or soft. "For precisely this question would be for future land emissions on comets of crucial importance.

Spacecraft meets comets - Artistic illustration NASA

Look at changes due to solar heat

At the same time, the visit of Stardust-NeXT to Comet Temple-1 opens a unique opportunity for researchers: for the first time, they can see the changes that a passage in the sunshine causes to a comet st. "Close encounters with the Sun are never going well for a comet, " explains Joe Veverka, scientific director of the Stardust NexT mission. The strong heat of the sun evaporates the ice in the cometary nucleus and lets it lose dust and gas. This cyclical loss of material ultimately leads to the end of a comet. Display

The astronomers have long suspected that the loss of material is not evenly distributed over the surface of the comets, but so far the evidence was lacking. This is exactly where Stardust NexT comes into play: the spacecraft photographs some of the surface areas that were recorded six years ago by the Deep Impact spacecraft. "For the first time we will be able to observe the same comet before and after its closest approach to the sun, " Veverka says. The new photos are intended to show how these areas have changed and how much material has been lost in the sun's orbit around the comet.

Ridiculous landslide and layers

One of the areas that is particularly exciting is a plateau on the surface of the cometary nucleus: "There is a large plateau that looks like a landslide, " explains Pete Shultz, also a member of the Stardust NeXT team. If it really is a landslide, then this means that only recently gas and dust have been ejected from the surface. How and if the plateau since the Deep Impact shots ver The flyby of Stardust-NeXT should now show.

Still puzzling are the signs of stratification that Deep Impact discovered five years ago. "The earth has strata, because water and wind move dirt and scree, but such stratification on a comet was a surprise, and a riddle, " Veverka said. How they could have arisen is unclear. Her colleague Shultz adds: "One possibility would be for two protocometare objects to collide and merge to look like a pile of pancakes." Again, the new images of Stardust -NeXt bring more information.

Stardust: from one comet to the next

Like the comet Temple-1, the probe that visits it already has a rich history behind it. The Stardust probe, equipped with special collecting paddles for dust samples, collected samples of interstellar dust on its mission for a mere seven-year mission, then collected further samples during a close flyby on Comet Wild 2. Then the probe flew back Undck and shot the dust samples stowed in a special retrieval capsule in the direction of the earth. These samples were recovered in early 2006 and subsequently analyzed.

Instead of completing the spacecraft mission, NASA decided to continue using Stardust and re-directing it towards a comet. "We could have let this old spaceship rest on its laurels, in an eternal orbit around the sun, " explains Veverka. But instead, we're doing world-class comet research again again. "

(NASA, 15.02.2011 - NPO)