Rosetta spacecraft awakens from solar slumber

21 Jan 2014

An artist's impression of the Rosetta spacecraft

After a tense few hours for its scientists, the Rosetta satellite sent to follow a comet awoke from its solar-powered hibernation yesterday as it returned within powering distance of the sun.

Currently just more than 1,083m km (673m miles) from the sun, the solar-powered Rosetta satellite, which was sent to follow comet 67P/Churyumov-Gerasimenko in 2004, has ended its 31-month silence to conserve energy after it began to receive solar energy once again.

The European Space Agency (ESA) satellite has made three flybys of Earth and one of Mars to help it on course to its rendezvous with 67P, encountering asteroids Steins and Lutetia along the way.

About 14m km (9m miles) from its eventual target, Rosetta’s internal alarm clock turned its instruments back on yesterday morning. The spacecraft then aimed its antennae towards Earth, and transmitted a signal at 6:18pm GMT to let home know everything was functional.

Highlighting the tense anticipation among the crew back on terra firma, Fred Jansen, ESA’s Rosetta mission manager, expressed relief once the radio signal came in: “This was one alarm clock not to hit snooze on, and after a tense day we are absolutely delighted to have our spacecraft awake and back online.”

Reaching Rosetta’s destination

Rosetta’s mission to reach comet 67P is hugely important for science, as it will get closer to a comet than any spacecraft previously and will hopefully provide plenty of data about the enormous space debris. When Rosetta reaches the comet, it will also become the first space mission to rendez-vous with a comet, the first to attempt landing a probe on a comet’s surface, and the first to follow a comet as it swings around the sun.  

Rosetta will start with two months of extensive mapping of the comet’s surface, and will also make important measurements of the comet’s gravity, mass and shape, and assess its gaseous, dust-laden atmosphere, or coma. The orbiter will also probe the plasma environment and analyse how it interacts with the sun’s outer atmosphere, the solar wind.

Using this data, scientists will choose a landing site for the mission’s 100kg Philae probe. The landing is currently scheduled for 11 November and team will be continuously testing Rosetta’s equipment to make sure it’s ready for its primary function.

They will also be updating the satellite’s progress on Twitter @ESA_Rosetta.

Colm Gorey was a senior journalist with Silicon Republic