| New York Times | - |
After
a seven-month slumber, a European spacecraft that landed on a speeding
comet last fall has awakened from hibernation and phoned home, the
European Space Agency said on Sunday.
After
a seven-month slumber, a European spacecraft that landed on a speeding
comet last fall has awakened from hibernation and phoned home, the
European Space Agency said on Sunday.
“We’re really excited to have the mission back in one piece, at least for a few more months,” Mark McCaughrean, senior science adviser at the agency, said in an interview.
The
solar-powered lander, deployed by the Rosetta orbiter, lost contact
with ESA on Nov. 15 after nestling into a shady crevice on the surface
of Comet 67P/Churyumov-Gerasimenko, according to ESA. The probe’s precarious position prevented full deployment of its solar panels, and after 60 hours of operation its batteries died.
ESA
predicted then that the lander, called Philae, could awaken once Comet
67P entered a sunnier path in its orbit, and since March 12 the Rosetta
team has been on high alert for signals from the probe. But the team did
not know whether the extra sunlight would recharge Philae’s batteries
or cast larger shadows over its shady spot. They also did not know
whether the probe’s equipment had frozen; the atmosphere on Comet 67P is
about minus 150 degrees Fahrenheit.
Multimedia Feature
Rosetta’s Philae Lander Wakes Up From Hibernation
The Rosetta spacecraft dropped the Philae lander onto
Comet 67P/C-G last November. After seven months, the lander is now
beginning to emerge from hibernation.
“I
became pessimist-in-chief to damper down the expectations,” Dr.
McCaughrean said. But late Saturday night in Europe, the agency received
a message from the lander, prompting Dr. McCaughrean to muse, “Hey,
it’s good to be proven wrong.”
The
agency connected with Philae for 85 seconds through Rosetta, the ESA
statement said. Philae sent 300 data packets from its memory systems
back to Earth and is expected to transmit about 8,000 more soon.
ESA scientists’ next task is to find out exactly where on the comet Philae is. They hope to study the comet’s density and internal structure and to drill about 10 inches into the dusty surface to analyze the ice that helps form the comet.
The
lander, which is about the size of a washing machine, has had a
tumultuous time since completing the 317-million-mile journey to its
historic touchdown on Comet 67P. Its anchoring harpoons and gas
thrusters failed, and it almost bounced out of the comet’s weak
gravitational field before landing in the shade and falling into
hibernation.
If
Philae’s landing had gone exactly as planned, the probe would have
probably shut down in March as its solar panels overheated, Dr.
McCaughrean said. But because it was shielded, it is ready to work while
Comet 67P is much closer to the sun.
“The
silver lining is that by not waking up until now, we’re actually at a
much more interesting time in the comet’s life,” Dr. McCaughrean said.
As Comet 67P nears the sun it begins to melt and lose particles. Philae
is now at ground zero as dust, ice and gases spew from the comet to form
its tail.
“We’re
now seeing this beast burst into life,” Dr. McCaughrean said. The
particles swirling past Philae could include carbon-bearing molecules
that offer clues to the origins of life, he said.
Comet
67P will be closest to the sun on Aug. 13. Dr. McCaughrean said Philae
may be able to operate for up to four months. The Rosetta mission is to
continue until September 2016, when the orbiter slowly descends to its
final resting spot
end quote from:
No comments:
Post a Comment