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Philae spacecraft makes historic landing on comet


The European Space Agency mission control in
Darmstadt, Germany, celebrates as Philae
touches down

The signal broke a seven-hour wait of
agonising intensity and sparked scenes of
jubilation at the European Space Agency’s
mission control in Darmstadt. The team in
charge of the Rosetta mission achieved what
at times seemed an impossible task by
landing a robotic spacecraft on a comet for
the first time in history.
The moment the tension broke came shortly
after 1600 GMT when the Philae called home.
“We are there. We are sitting on the surface.
Philae is talking to us,” said a jubilant
Stephan Ulamec, Philae lander manager at
the DLR German space centre. “We are on
the comet.”
Andrea Accomazzo, the Rosetta flight
operations director, added: “We cannot be
happier than we are now.”
But celebrations were tempered by the later
discovery that the probe’s two harpoons had
not fired to fasten the craft down in the
ultra-low gravity. Scientists now think the
probe may have bounced after first coming
into contact with the surface. Ulamec said:
“Maybe today we didn’t just land once, we
landed twice.”
The safe, if precarious, touchdown of the
lander gives scientists a unique chance to
ride onboard a comet and study from the
surface what happens as its activity ramps up
as it gets closer to the sun. The first images
beamed back from the lander’s descent
revealed a dramatic landscape of pits and
precipices, craters and boulders. However,
there have been gaps in its radio link with
the orbiting Rosetta mothership.


The Philae lander on its way to the comet,
photographed by the Rosetta spacecraft.
Photograph: AP

The £1bn ($1.58bn) Rosetta mission aims to
unlock the mysteries of comets, made from
ancient material that predates the birth of
the solar system. In the data Rosetta and
Philae collect, researchers hope to learn more
of how the solar system formed and how
comets carried water and complex organics
to the planets, preparing the stage for life on
Space agencies have sent probes to comets
before, but not like this. In 1986, Nasa’s Ice
mission flew through the tail of Halley’s
comet. In 2005, the agency’s Deep Impact
spacecraft fired a massive copper block at
comet Temple 1. But none before now has
The feat marks a profound success for the
European Space Agency (ESA), which
launched the Rosetta spacecraft more than 10
years ago from its Kourou spaceport in
French Guiana. Since blasting off in March
2004, Rosetta and its lander Philae have
travelled more than 6bn kilometres to catch
up with the comet, which orbits the sun at
speeds up to 135,000km/h.
“We are the first to do this, and that will stay
forever,” said Jean Jacques Dordain, director
general of the ESA.
Matt Taylor, a Rosetta project scientist, who
had selected an extremely colourful shirt for
the event, revealed an impressive – and
brave – tattoo of the lander on the comet’s


Scientists celebrate at the space centre in
Toulouse as they learn that Philae has landed.
Photograph: Remy Gabalda/AFP/Getty Images

“Comets are the original source of Earth’s
water. That wee lander is now in position,
poised to re-write what we know about
ourselves,” tweeted Chris Hadfield, the
former Canadian astronaut and commander
of the International Space Station.
Early data from the lander revealed that it
had had a softer landing on comet 67P than
expected. But an hour after the landing
signal came through, Paolo Ferri, the ESA’s
head of mission operations, said that Philae’s
twin harpoons, which are intended to secure
it in place, had not fired, raising fears about
the lander’s stability and chances of clinging
on to the comet for long.
Touchdown for the lander played out 510m
kilometres from Earth, between the orbits of
Mars and Jupiter, on a comet hurtling
through space at more than 18km/s. At so
vast a distance, even radio signals travelling
at the speed of light take nearly half an hour
to travel from Earth to the spacecraft, making
real-time control of the landing impossible.
Instead, the entire descent was precalculated,
uploaded and run automatically.
Landing Philae on the comet’s surface was
never going to be easy. When ESA managers
got their first closeup of the comet in July, its
unusual rubber duck shape left some fearing
that a safe touchdown was impossible. The
shape was not the only problem. The comet’s
surface was hostile: hills and spectacular
jutting cliffs gave way to cratered plains
strewn with boulders. If Philae landed on
anything other than even ground it could
topple over, leaving it stranded and defunct.
Rosetta spent weeks flying around the comet
to create a surface map from which mission
controllers could choose a landing site. They
faced a trade-off: the site had to be fairly flat
and clear of boulders, but with a good view
of the whole comet and plenty of sunlight to
charge the lander’s batteries. From a shortlist
of five potential landing spots, scientists and
engineers unanimously voted for a 1 sq km
region on the comet’s “head” later named

Read the complete story HERE.

Source: The Guardian.

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