Down, down we go to 29 km – or lower?

Tweet Editor’s note: The Rosetta mission control team are transitioning Europe’s intrepid craft onto the next stage of cometary operations: the Global Mapping Phase (GMP). The update below is based on inputs provided by Flight Director Andrea Accomazzo at ESOC and Project Scientist Matt Taylor at ESTEC. Before you read today’s post, take a quick look at our trajectory video to refresh your memory (we know you’ve already seen this – but it’s a very helpful aide memoire), which illustrates what Rosetta is doing now (skip through to the 00:58 – Global Mapping) Note also that some round-figure references to “30, 20 or 10km” refer, specifically, to 29, 18.6 or 9.8 km, respectively. We are now in the Transition to Global Mapping (TGM) phase, that is, the two hyperbolic segments of the trajectory that move us from the 50km pyramid of the Close Approach Phase (CAT) to the 30-km gravitationally bound orbit of the Global Mapping Phase (GMP). “The aim of GMP is to get as close as we can and gather as high-res science data as we can to best characterise the potential landing sites – helping us to make the best decision on prime and backup and really start to understand what kind of thing we're dealing with,” says Fred Jansen, ESA’s Rosetta Mission Manager. “It's a real synthesis of operations, science and analysis that is a first in many ways.” On Wednesday, 10 September, 09:00 UTC (11:00 CEST) the spacecraft will be at the terminator plane (the plane passing through the centre of the comet and perpendicular to the Sun direction) and will perform a 19-cm/s manoeuvre (thruster burn) to insert the spacecraft onto the 30-km circular orbit. "The orbital plane is 60 degrees away from the Sun’s direction and is such that we will orbit over […]



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