Sleeping Rosetta spacecraft wakes up for comet rendezvous

The Rosetta space orbiter is to be moved closer to the comet hosting the pioneering Philae lander to establish a better with link the probe after it sent back signals last weekend, the European Space Agency has announced.

In a briefing on the mission at the Paris air show, the agency confirmed there had been no contact with the solar-powered probe since its surprise reactivation over the weekend when it signalled to its orbiting mothership Rosetta.

The agency’s scientists and engineers gave details of how the Rosetta trajectory has been changed to “optimise the opportunities for lander-to-orbiter communication”.

Two operations on Wednesday and on Saturday, referred to as “dog-leg” burns, will bring the orbiter to a distance of 180km from comet 67P Churyumov-Gerasimenko – more than 40km closer than its previous trajectory.

“The key here is to maximise the communication with Philae,” Elsa Montagnon, Rosetta’s deputy flight director told the briefing. She explained that if the orbiter got too close it would shut down because of dust thrown up in the comet’s wake. She likened the mission to driving through a snow storm.

The Philae probe made contact with agency for the first time in seven months on Saturday, and has sent back hundreds of packages of valuable data. It had been silent since a partially botched landing last November.

If more contact can be established the probe will able to send back more data than if it had landed in the spot it was meant to, scientists said.

Montagnon confirmed that there was contact for 85 seconds on Saturday night. The comet then made one revolution in which there was no contact, but then a further three 10-second bursts were received on Sunday evening, she said.

Jean-Pierre Bibring, the lead scientist on the project, told the briefing that the mission had already been a success because it had been so unexpected and challenged existing paradigms. He said the mission could now “go beyond expectations”, if longer periods of contact were made with the probe.

He said the probe’s reawakening showed it survived temperatures of minus 150 degrees. He acknowledged that the probe would probably have overheated if it had not landed under the shadow of an area of the comet identified by the scientists as the “Perihelion cliff”. He said: “Although we are in shadow we survived and that is really amazingly fantastic.”

Bibring said that the material already gathered from the lander is “amazingly exciting” because it gives detail of the material that modelled the solar system.

He said: “We have got still some fine-tuning to make. But essentially now we are in a position not only to wake up but to resume science to an extent that might go beyond our expectation.”

The Rosetta orbit has picked up “bizarre pits” on the surface of the 4km wide comet, senior scientist Mark McCaughrean told the briefing. “These pits are alive – we see material flowing out, this is not a dead body at all. Fantastic jets emerge even in the darkness,” he said.

The agency reckons there is a great chance of contact with the probe as the comet’s orbit reaches its closest point to the sun this August.

McCaughrean said: “This extraordinary journey is by no means over. We are not at a dead object, we are at a living breathing dragon of a comet, which is coming to life as we come closer to the sun.”

Bibring added: “The dream that we put together is still there because the fact that Philae not only woke up but gave a signal has opened new excitement to complete the mission and possibly go beyond it.”

The team at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) received data from the Philae lander for the third time on 19 June 2015. Between 15:20 and 15:39 CEST, Philae sent 185 data packets. "Among other things, we have received updated status information," says Michael Maibaum, a systems engineer at the DLR Lander Control Center (LCC) in Cologne and Deputy Operations Manager. "At present, the lander is operating at a temperature of zero degrees Celsius, which means that the battery is now warm enough to store energy. This means that Philae will also be able to work during the comet's night, regardless of solar illumination." In the 19 minutes of transmission, the lander sent data recorded last week; from this, the engineers determined that the amount of sunlight has increased: "More solar panels were illuminated; at the end of contact, four of Philae's panels were receiving energy". There were a number of interruptions in the connection, but it was otherwise stable over a longer period for the first time. “The contact has confirmed that Philae is doing very well.”

The probe said it had 8,000 data packets when it contacted us,

Hawkeye, Every dire prediction you have made on this thread has turned out to be false. It is like this little lander is working extra hard to prove you wrong.

I hope NASA appreciates you.

If Philae averages 200 packets a day, it will finish it's transmission in under 40 days. There are a lot more than 40 days left on this mission.

The best time for power will be in August

The mission was expected to last through Dec of 2015 and will probably be extended well in to 2016.

The orbiter is not moved into a dangerous position.

First you refer to yourself in the second person (we}, the in the third person (speaking about what "Hawkeye" has done), and now in the second person again. You are no part of the ESA, you have no place to speak about what "we" have done.