At the Royal Aeronautical Society the European space agency were telling that the icy comet takes 12.4 hours to complete one rotation; but they have observed that it has extended by about a second a day and this rate of change is increasing as the comet gets active.
So the comet which is observed by Europe’s Rosetta satellite is very gradually spinning down.
Flight director Andrea Accomazzo said “The gas jets coming out of the comet – they are acting like thrusters and are slowing down the comet.”
He further added that his team has learnt to fly Rosetta around the 10-billion-tonne, 4km-wide body with remarkable precision.
Navigators use a system of landmarks on the comet to understand how it is rotating and moving through space. This information is fed into a model that helps plan a trajectory for the satellite. While collecting this information they realized that it is not turning up in the right place.
In September last year also the rotation period extended by 33 ms per day.
Now as the comet is approaching towards sun it is throwing out gases and dust the rotation speed has reached a second per day.
Accomazzo said, “OK, it’s not going to slow down completely – but this gives you an order of magnitude for the accuracy we’re now achieving with the navigation of the spacecraft around the comet.”
Philae the lander ran out of power and is currently hibernating. The scientists are waiting for it to get charged. Philae need temperature higher than -45 degrees Celsius and atleat 5 watts of power to turn on and sent the signals to earth via the orbiter.
Scientists are hoping that the Philae reawakens as the Comet 67P approaches the sun.