Europe’s Rosetta spacecraft was headed for a mission-ending crash Friday on the comet it has stalked for two years, a dramatic conclusion to a 12-year odyssey to demystify our Solar System’s origins.
Sent by ground controllers on a leisurely, 14-hour freefall, the space pioneer was engaged in a last-gasp spurt of science-gathering on the 19-kilometre (12-mile) journey to its icy comet tomb.
The moment of impact will be 1038 GMT, give or take two minutes, the European Space Agency said after overnight measurements allowed it to narrow down the expected time of death.
Confirmation will arrive 40 minutes later, the time it takes for a message to travel between Rosetta and Earth, when the spacecraft’s signal dies off ground controllers’ computer screens.
“Everything is going according to plan,” project scientist Matt Taylor told AFP.
“We had a few small things going on this morning but it was mainly due to people resetting computers or backing computers up. Everything’s looking smooth.”
The craft has been sending back close-up shots of Comet 67P/Churyumov-Gerasimenko, and “we’re seeing some really nice images,” said Taylor.
“We just wait for the end now.”
It was also meant to sniff the comet’s gassy coma, or halo, and measure its temperature and gravity from closer than ever before.
Rosetta has been commanded to join long-spent robot lander Philae on 67P for a never-ending journey around the Sun.
With the comet zipping through space at a speed of over 14 kilometres (nine miles) per second, it was programmed to make a “controlled impact” at human walking speed, about 90 cm (35 inches) per second.
Mission scientists expect it will bounce and tumble about before settling—but Rosetta’s exact fate will never be known as it was instructed to switch off on impact.
The comet chaser was never designed to land.
“You can see some of the flight control team, the people who work here in mission control, are beginning to get more emotional because they can see the end,” Taylor said.
“People who work on mission control, their entire existence is based on making sure the spacecraft stays healthy, so they have to switch their head round. It’s a 180-degree turn, now you’re going to kill the spacecraft.”
For the scientists like himself, who will sift through the data gathered for years, possibly decades, to come, there was also a sense of excitement, Taylor said.
“It’s a bittersweet thing. There is something about the attachment, there’s something about that spacecraft being there. I will feel a sense of loss, surely.”
Another highlight of the final hours was the one-off chance to peer into mysterious pits dotting the landscape for hints as to what the comet’s interior might look like.
The first-ever mission to orbit and land on a comet was approved in 1993 to explore the birth of our Solar System 4.6 billion years ago.
Rosetta and lander probe Philae travelled more than six billion kilometres over 10 years to reach 67P in August 2014.
Philae was released onto the comet surface in November of that year, bouncing several times, then gathering 60 hours of on-site data which it sent home before entering standby mode.
Comets like 67P are thought to contain primordial material preserved in a dark space deep freeze.
Insights gleaned from the 1.4-billion-euro ($1.5-billion) project have shown that comets crashing into an early Earth may well have brought amino acids, the building blocks of life.
Comets of 67P’s type, however, certainly did not bring water, scientists have concluded.
Date created : 2016-09-30
Article source: http://www.france24.com/en/20160930-rosetta-space-crash-comet