After returning from the far end of its orbit, Rosetta is back where the sun's energy is sufficient to power the spacecraft and has awoken after 31 months of hibernation
The European Space Agency's Rosetta spacecraft woke up today after a 31-month hibernation. Rosetta is chasing Comet Churyumov-Grasimenko and will become the first spacecraft to meet a comet, try to land a vehicle on its surface and the first to follow it around the Sun.
Since its launch in 2004, Rosetta has made three passes near Earth and one pass near Mars in preparation for the encounter with the target comet, photographing the asteroids Steins and Lutetia along the way. In June 2011, at a distance of 800 million kilometers from the Sun, close to Jupiter's orbit.
Now Rosetta is in an orbit that has brought it to a distance of 'only' 673 million kilometers from the sun and the energy of the sun where it is is enough to return the spacecraft to activity. It is still 9 million kilometers from the comet. Rosetta was pre-programmed with an 'alarm clock' that woke her up today. After warming up its main navigation systems, exiting its stabilization vortex, and aiming its radio antenna at Earth, Rosetta sent a message that let the operators in the control room know that it had survived the most distant part of its journey.
The signal was received at NASA's Goldstone ground station in California at 20:18 Israel time, as part of the first window of opportunity for communication between Rosetta and Earth. The signal was confirmed by the operations center of the European Space Agency in Darmstadt and they hurried to tweet on Twitter (a service that did not exist yet when the spacecraft was launched) "Hello world".
"The comet chaser is back" said Alvaro Jimenez, director of robotic and scientific space exploration at the European Space Agency. "With Rosetta, we are taking the study of comets to a new level. This impressive mission continues our history of firsts in comets, based on the technological and scientific achievements of the Giotto mission that brought the first close-up images of Halley's comet nucleus in 1986."
In the next step, European Space Agency personnel will carry out proper tests for the spacecraft's systems, for the 11 instruments on the spacecraft and ten more on the Philae lander to be lit and prepared for the study of the Churyumov-Gresimenko comet. The first images of the comet are expected to arrive in May when Rosetta will be 2 million km away from it. Towards the end of May, Rosetta will perform two maneuvers to adapt to the critical encounter with the comet in August.
After approaching and attaching to its orbit, Rosetta will begin two massive months of mapping the comet's surface, providing data on the comet's gravity, mass and shape, and evaluating the composition of the atmosphere or halo, which consists of gas and dust. The orbiter will also study the plasma environment and analyze how it interacts with the Sun's outer atmosphere or solar wind.
This data will help scientists choose a landing site for the 100 kilogram Philae lander. The landing is scheduled for November 11 and will be the first planned soft landing on a comet. Given the low gravity of a comet core that is about 4 kilometers in diameter, Philae would be required to use ice screwdrivers and bells to stop it from flying back into space after touching down.
see also My skin, Rosetta!
