Philae could be forgiven for feeling a little neglected. While Nasa’s New Horizons probe has been hogging the headlines after its brush past Pluto, the European-built lander has been chugging quietly around the Sun on the back of its comet with little but the occasional radio signal to show for its pains.
All that is about to change. Despite the near-catastrophe of Philae’s bumpy landing on Comet 67P Churyumov-Gerasimenko last November, it has managed to send back a bundle of data that could change our understanding of the early solar system.
The first full package of results from the lander’s instruments will be published in two leading scientific journals this month.
The British-led team of scientists running Philae’s shoebox-sized gas analyser, known as Ptolemy, used the tool to “sniff” the dust rising from Comet 67P’s surface after the lander bounced on arrival. Six more attempts followed as Philae gradually came to a rest next to a cliff more than a kilometre away from the spot where it was supposed to land, each gleaning only a handful of results.
Then came the most important and precarious experiment of all. With only 45 minutes to go before Philae slipped into hibernation when its main battery died, the scientists switched on the power-hungry “Case” oven to analyse the chemistry of the surface in search of organic compounds.
Geraint Morgan, a space scientist at the Open University who played a leading role in the research, said that he and his colleagues had found themselves in a race against the clock after their plans had been left in tatters by the crooked landing.
“Having spent several years writing the programs, and it had all been uploaded to the lander, we basically had to rewrite the entire script and send [PHILAE]a new program,” he said. “Then we had to condense a four-hour experiment into approximately half an hour. We were terrified, but the reality was we had got it right. We managed to switch it off just in time.” The gamble paid off: Ptolemy’s mass spectrometer made 275 chemical assays, compared with only six in each of the previous bursts.
“We had data about ten or 15 minutes after the first bounce, which was the dust thrown up by the comet, so we’re able to look for the building blocks of life, and then there was the second bounce and we were able to analyse the out-gassing of the comet [gases seeping up from below the surface], and we found some quite interesting things,” Dr Morgan said.
He will present the findings — which are “really quite different from what we anticipated” — in a Lab Innovations symposium at the Royal Society of Chemistry in London later this year.
The make-up of the gases and organic compounds is expected to shed light on the infancy of the planets. Comet 67P is believed to originate in the Kuiper Belt, the same mysterious ring of rocks on the fringe of the solar system that will swallow the New Horizons probe over the next two decades.
“The comet is a dirty snowball,” Dr Morgan said. “It’s where most of the water left over from the early solar system can be found. It’s like travelling four and a half billion years back in time. Comets have got a kind of crust outside which has a very low albedo — which means it’s made of dark stuff, presumably organic compounds.”
By Oliver Moody
With many thanks to The Australian
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