Return to Website

Number Watch Web Forum

This forum is about wrong numbers in science, politics and the media. It respects good science and good English.

Number Watch Web Forum
Start a New Topic 
View Entire Thread
Re: Rosetta space mission compromised by Green technology

I noticed a recent article about the Philae probe where it looks like ESA made another over-optimistic assumption about the comet. At the time of the comet landing, the harpoon anchorage system for the lander failed, and this was given as the main reason by the mainstream media for the landing mission not being a complete success - failure to anchor to the comet's surface at the first impact resulted in the probe bouncing about on the surface and settling in a well-shaded location where the illumination was too weak to recharge the solar-powered batteries.

According to the Rosetta mission scientist Matt Taylor (most well-known for being attacked by feminist activists for wearing what they regarded as an inappropriate shirt at the mission's press conferences), the comet's surface was much harder than expected, and the harpoons might have failed to embed in the surface material at all if the system had actually worked, resulting in an unintentional extra recoil force which might have sent the probe completely back into space rather than just experiencing a high first bounce.


There seems to be a strange working culture operating in this European Space Agency. In most industries, you tend to make pessimistic assumptions when dealing with the unknown. This lot seem to think that when you deal with the unknown all you have to do is follow whatever are the text book assumptions, and if that doesn't work, you were unlucky. So the text book assumption is that a comet is a 'dirty snowball' in composition that you should be able to grab at the first impact with some harpoon anchoring system. The text book assumption is that comets will have a nice round shape rather than having some irregular shape even though nobody has actually seen one close up.

Re: Rosetta space mission compromised by Green technology

The ESA organisation is a very strange beast indeed and probably not susceptible to normal argument. I have to work under their edicts on a daily basis and they often seem irrational to me.

Re: Rosetta space mission compromised by Green technology

On this subject of space missions being compromised by Green technology, there was a news story today about a NASA satellite orbiting Mars managing to locate the ill-fated British space probe "Beagle 2" on the surface of Mars. Beagle 2, which was designed to look for signs of life on Mars, landed in December 2003, and was assumed to have been effectively destroyed in the landing operation (as I remember it, the man in charge of Beagle 2, the late Colin Pillinger, claimed they had been caught out by a 'Martian heatwave' making the atmospheric conditions a bit different from what had been designed for).


It turns out that the probe did land in an intact state rather than being destroyed, and landed within 5 km of the centre of its target location, but it appears that it failed half-way through the operation of unfolding its arrangement of disk-mounted solar panels, possibly due to the discs being excessively deformed by the landing. The solar panel arrangement had to unfold completely before it could contact Earth, and it was then going to send a signal to Earth composed by British pop group Blur as I remember it. Basically, as far as I can see, the mission seems to have failed because the probe was designed to use solar power - if it had been using a robust and reliable power source like an RTG, the mission would probably have been a success.

If the Green lobby had never existed, then in my opinion RTGs would probably be used routinely to power spacecraft that are designed to land on planets, moons, comets, etc. But due to the influence of this lobby, solar power has to be the first choice for these landing missions, with RTGs only allowed in unusual situations that have to be justified.