ESA's Rosetta Spacecraft Days Away From Waking Up For Comet Visit

Lee Rannals for redOrbit.com – Your Universe Online

The European Space Agency’s (ESA) Rosetta spacecraft is less than a week away from waking up from a deep hibernation to explore a comet, in what is being hailed as a first-of-its-kind attempt.

Rosetta has been catching up to comet 67P/Churyumov–Gerasimenko since it launched in 2004. During its journey, the spacecraft has used the gravitational pull of Earth and Mars to help put it on the proper trajectory towards the comet.

ESA placed Rosetta in hibernation mode back in 2011 to help it with its toughest part of the journey to 67P/Churyumov–Gerasimenko. Rosetta was positioned in a way so its solar arrays faced the Sun and was put into a once-per-minute spin for stability. Currently, the only devices running on Rosetta are its computer and heaters, but beginning January 20 the spacecraft will be waking up in preparation for its comet visit.

“Thirty-one months later, Rosetta’s orbit has brought it back to within ‘only’ 673 million kilometers (418 million miles) of the Sun, and there is finally enough solar energy to power the spacecraft fully again. It is time to wake up,” ESA said in a statement.

When Rosetta wakes up, it will fire its thrusters to help stop the slow rotation, and a slight adjustment will be made to its orientation to ensure the solar arrays are facing directly at the Sun. After this, Rosetta will warm up its startrackers, which will take about six hours. The startrackers will help ESA determine the spacecraft’s attitude.

“Once that has been established, Rosetta will turn directly towards Earth, switch on its transmitter and point its high-gain antenna to send its signal to announce that it is awake,” ESA said.

The signal will take about 45 minutes to reach the ground stations on Earth, which will be between 17:30 GMT and 18:30 GMT. When the signal is received, it will be relayed to ESA’s Operations Center in Darmstadt, Germany.

After Rosetta’s health has been evaluated, the spacecraft’s scientific instruments will be switched on and tested, which could take several months. The spacecraft will still be 5.5 million miles away from the comet when it wakes up, giving ESA plenty of time to test out its instruments before the spacecraft reaches its final destination.

Rosetta will be the first mission to rendezvous with a comet, land on it, and follow it as it swings around the sun for perihelion. The mission was designed to help researchers understand more about what scientists consider the building blocks of the Solar System. While many questions about how these objects feed the solar system remain, as well as the anatomy of them, Rosetta will help unlock these unanswered questions.