Europe's pioneering Rosetta spacecraft concluded a 12-year odyssey with a
controlled crash-landing Friday Sep 30,2016 onto the comet it has orbited and
probed for two years to unravel the secrets of the Solar System's birth,
mission controllers said.
"I can confirm the full success of the
descent of Rosetta," Mission Manager Patrick Martin announced to wild
cheering in the control centre, based in Darmstadt near Frankfurt in
Western Germany.
"Rock-n-roll Rosetta," added a visibly moved
Matt Taylor, the mission's project scientist, as he stepped from the
podium, holding -- and shaking -- his head.
In the hours before
the crash-landing, Rosetta gathered crucial last-gasp data from nearer
the galactic wanderer than ever before, its instruments primed to sniff
the comet's gassy halo, measure temperature and gravity, and take
close-up pictures of the spot that is now its icy tomb.
The craft
had been programmed for a "controlled impact", at a human walking pace
of about 90 cm (35 inches) per second, after a 14-hour freefall from an
altitude of 19 kilometres (12 miles).
Confirmation of the
mission's end came at 1119 GMT, when the spacecraft's signal -- with a
40-minute delay -- faded from ground controllers' computer screens.
The
trailblazing craft's final manoeuvre was executed at a distance of 720
million kilometres (450 million miles) from Earth, with the comet
zipping through space at a speed of over 14 kilometres (nine miles) per
second.
Mission scientists expected it would bounce and tumble about before
settling -- but Rosetta's exact fate will never be known as it was
instructed to switch off on first impact.
The comet chaser was never designed to land.
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.
Having made the closest approach on its 6.6-year loop around the Sun in
August last year, the comet is now moving further and further away from
our planetary system's central star, which means Rosetta's solar panels
are catching fewer battery-replenishing rays.
Rather than just
letting it fade away, scientists opted to end the mission on a high by
taking measurements from up close -- too close to risk under usual
operating conditions.
Bittersweet
On
Thursday night, Rosetta was commanded to exit comet orbit and join
long-spent Philae on 67P for a never-ending journey around the Sun.
Flight
operations director Andrea Accomazzo, working on Rosetta for nearly 20
years, confessed "of course there is a bit of sadness" after a "long,
long" professional investment.
"You are going to miss it. But OK, life goes on," he shrugged.
For the scientists who will sift through the data for years, possibly decades, to come, this is not the end, however.
