ROSETTA LANDING SITES CHOSEN

ESA project managers have now selected a longlist of  five potential landing sites on Comet 67P:
http://www.bbc.co.uk/news/science-environment-28923010

If the comet is considered to look like a rubber duck, three of the sites are on the head, two are on the body. The neck region has been ruled out

The decision was made principally on operational grounds, where engineers believe the Philae landing probe can touch down on the comet surface with least risk. Other considerations included the need for a location that experiences a day/night cycle, and a place free from boulders and fissures.

Philae is described as 'washing machine-sized'. Comet 67P has a maximum dimension of about 4.5 km.

Landing on a comet has never been attempted before.

A final decision on the landing site is expected by mid-October. The landing attempt is scheduled for 11 November 2014. Due to the distance from Earth, real-time radio control will be impossible. The landing commands will be uploaded several days in advance.

Comment: This is a dramatic and risky mission, but if successful promises to yield valuable scientific understanding about the nature of the comet. The impossibility of real-time control due to the distance involved and the speed of the radio signals is an interesting feature of operating at large distances from Earth. It is significant when, as in this case, important decisions may be required on a timescale short compared to the travel time of the signals.