Rosetta to Meet Steins in 8 hrs’ Time
Rosetta is an European Space Agency (ESA) spacecraft designed to orbit and land on a comet. You read it right, to orbit and land on a comet.
Steins is an asteroid roughly 10 km in diameter, located in the main asteroid belt between the orbits of Mars and Jupiter.
The story goes like this… Rosetta is planned to rendezvous with a comet named 67P/Churyumov-Gerasimenko (don’t ask me how to pronounce that!) in 2014. After it enter orbit around the comet, Rosetta will release its “baby” – Philae Lander – onto icy nucleus. This is the first mission designed to orbit and land on a comet.
Rosetta initial target was not Churyumov-Gerasimenko; it was supposed to be 46P/Wirtanen (this is much easier to pronounce), with the encounter planned for 2011. However, after postponement of the initial launch in January 2003, the spacecraft was launched in March 2004 and will meet its new target – Comet 67P/Churyumov-Gerasimenko.
During its 10 years journey to the comet, Rosetta will pass by two asteroids: 2867 Steins on 5 September 2008 and 21 Lutetia on 10 June 2010. So, about 8 hours from now, Rosetta will reach closest approach to Steins, targeted to be 800 km from the asteroid, passing by at a speed of 8.6 km/s relative to Stein.
Latest post from the Rosetta Blog said that the analysis of Rosetta’s and Steins’ location enabled the mission team to determine that Rosetta will pass within 2 km of the targeted 800 km, which is within acceptability for the science observations to come.
An artist impression of ESA’s Rosetta spacecraft flew by asteroid (2867) Steins while on its way to Comet 67P/Churyumov-Gerasimenko. The study of asteroids is extremely important because they represent a sample of Solar System material at different stages of evolution – key to understanding the origin of our own planet and of our planetary neighbourhood. Credits: ESA.
Between 40 and 20 minutes before closest approach, Rosetta will be flipped and the spacecraft will switch to a specially designed asteroid fly-by mode, an optimal configuration that supports the intensive observation and tracking activity of the on-board instruments. Although most scientific observations will take place in the few hours around closest approach, several instruments will be switched on for a longer time around the event.
Around closest approach, Rosetta will be 2.41 Astronomical Units, or about 360 million km, from Earth. Radio signals sent to and from the spacecraft will have a 20 minute one-way travel time.
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