Tomorrow the European Space Agency’s Rosetta robotic spacecraft will rendezvous with comet 67P/Churyumov-Gerasimenko, some ten and a half years after the space probe was launched. In that time it has travelled 404,523,421 km (251,359,200 miles). It will be, according to the ESA’s website, ‘the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander to its surface.’
The whole event is being livestreamed, from 8.00 am GMT (9.00 am British Summer Time), here, as Rosetta is deployed into orbit around the comet.
I will certainly be watching this historic event. It has been so exciting watching as Rosetta approached the comet over the last month or so, from the first initial pixelated views that resolved themselves into the ‘rubber duck’. The scientists have to choose carefully where to place the lander on this slowly rotating chunk of space ice (water is a major volatile component of comets, along with carbon monoxide, methanol and ammonia.)
The comet pictured by Rosetta on 4 July 2014.
Rotating view of the comet captured by Rosetta on 14 July 2014.
The comet imaged from a distance of 1,000 km by Rosetta on 1 August 2014.
Once Rosetta is safely in orbit, it will begin to map and characterise the comet. Using the information it provides, a landing site will be selected for the lander.
According to the ESA website, the timeline is:
Comet mapping and characterisation (August 2014)
Less than 200 kilometres from the nucleus, images from Rosetta show the comet’s spin-axis orientation, angular velocity, major landmarks and other basic characteristics.
Eventually, the spacecraft is inserted into orbit around the nucleus at a distance of about 25 kilometres. Their relative speed is now down to a few centimetres per second.
The orbiter starts to map the nucleus in great detail. Eventually, five potential landing sites are selected for close observation.
Landing on the comet (November 2014)
Rosetta’s Philae lander on comet.
Once a suitable landing site is chosen, the lander is released from a height of about one kilometre. Touchdown takes place at walking speed — less than one metre per second.
Once it is anchored to the nucleus, the lander sends back high-resolution pictures and other information on the nature of the comet’s ices and organic crust.
The data are relayed to the orbiter, which stores them for transmission back to Earth at the next the period of contact with a ground station.
Rosetta and the comet.
So exciting. Can’t wait for tomorrow!