Fifteen months after the European Space Agency’s Philae probe made a historic landing on comet 67P/Churyumov-Gerasimenko, Matt Taylor, a mission scientist, has told Al Jazeera that there are things the team would have done differently.
In November 2014, the probe failed to lock itself on to the surface of the comet after its thruster and harpoons failed.
Instead, it bounced off the comet, coming to land two hours later and about 1km from the original landing site.
“Maybe [we should have] painted the lander [with] yellow and pink stripes to make it easier to see on the surface!” said Taylor.
He said the bounce gave the probe the chance to collect more data about the comet, even if the probe’s mothership Rosetta was subsequently unable to find its precise location.
“We have only been able to get within 20km of the surface to image the location of the lander,” Taylor said.
“At that height the lander appears as only a few pixels in the camera, and the comet surface has numerous features of the same size, so it has been impossible up to now to unambiguously identify the lander.”
Despite its unplanned landing, the probe was able to carry out a large part of its scientific mission and transmit the data to Rosetta, before its batteries died.
Very hard surface
The probe detected a number of organic molecules, previously not known to exist on comets, and also revealed that the comet had a very hard surface covered in a layer of dust.
“Philae’s measurements revealed that the comet did not have an intrinsic magnetic field,” Taylor said.
“This suggests that magnetic field may not have played a major role in the formation of small bodies in the solar system, meaning many solar system formation models had to be scrapped.”
As the comet came closer to the sun, it became more active and the additional sunlight saw Philae’s batteries come back to life.
This allowed it to transmit data to Rosetta, which was orbiting from a safe distance – but its last contact was made in July 2015.
Last week, with the comet now moving away from the sun at a speed of about 135,000km/hr, the team announced that they had given up hope of contacting Philae and would stop sending or trying to receive data from the craft.
As the comet moves away from Sun and becomes less active, the members of the team are focusing their attention on Rosetta and the first ever attempt to fly a spacecraft through the tail of a comet.
“This will focus on the plasma interactions that occur there, the interaction of the suns outer atmosphere with the dust and gas coming from the comet,” said Taylor.
After that, the team will gradually edge Rosetta towards the comet, which is now 350 million km from the sun, eventually carrying out a controlled impact in September.
“We only had two options with the orbiter – turn it off or crash it,” said Taylor.
“We wanted to get as close as possible, to get the highest resolution and best quality measurements, so crashing seemed obvious choice, so the finale is very exciting.”