"How hard is this landing?" asks Art Chmielewski, the US Rosetta Project Manager. "Consider this: the comet will be moving 40 times faster than a speeding bullet, spinning, shooting out gas and welcoming Rosetta on the surface with boulders, cracks, scarps and possibly meters of dust!"
Philae will take 7 hours to fall 22.5 km from the spacecraft to the comet--an interval some mission scientists are calling "The Seven Hours of Terror." Confirmation of the landing will reach ground stations on Wednesday at approximately 1600 UT. You can follow the descent as it happens by tuning in to ESA's #CometLanding webcast. www.spaceweather.com