Sleeping Comet Chaser to Get Wake-Up Call

Artist view of the Rosetta spacecraft. Rosetta’s lander, Philae, is attached and is shown in blue (© ESA/J. Huart)

The European Space Agency’s comet chasing Rosetta spacecraft is about to wake up from a 31-month nap, which was induced to conserve power after the vehicle ventured too far from the sun.

While ESA officials are confident Rosetta will respond when they try to rouse it this Monday, Jan. 20, they also realize anything could happen since the spacecraft is now in deep space some 807 million kilometers from Earth.

For the last 10 years, Rosetta has been traveling through the solar system for a rendezvous with comet 67P/Churyumov-Gerasimenko or 67P/CG.

The Rosetta spacecraft and mission were designed to perform a detailed investigation of a comet.

Rosetta was put into hibernation mode in 2011 when its trajectory to the comet took it so far from the sun that it was unable to use solar arrays to gather the energy needed to power it.

Artist’s impression of Rosetta’s lander Philae on the surface of comet 67P/Churyumov-Gerasimenko. (© ESA/ATG medialab)

After Rosetta was powered down, only its computer and several heaters were left running.

Also, to stabilize the spacecraft for its long trip to the comet, the ESA put it into a once-a-minute spin.

Now, 31 months after being put into hibernation, Rosetta’s trajectory has brought it back to where it’s closer to the sun and can gather enough solar energy to reach full power again.

After putting the spacecraft through a number of wake-up maneuvers, mission controllers at ESA’s European Space Operations Center in Darmstadt, Germany, will transmit a signal to Rosetta to take it out of its stabilizing spin and orient it so that its solar arrays face the sun, allowing it to draw enough energy to power-up and continue its mission as planned.

ESA says the Rosetta mission will give scientists the opportunity to gain some insight into the creation of the solar system and its planets.

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“Comets are very interesting objects, said Mark McCaughrean, ESA’s senior scientific advisor for space science missions. “They are effectively time capsules; they’ve locked up material which is left over from the birth of our own solar system. So by going to a comet, examining it in detail, studying its materials, what it’s made of, we hope to learn a lot more about the origin of the solar system we live in today.”

By studying the water that is locked up in comet 67P/CG, Rosetta mission officials hope to learn more about where the Earth’s water came from.

Image of the asteroid Lutetia taken at Rosetta’s closest approach.(© ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA)

McCaughrean says that since the Earth was too warm to hold much water after it was born, our ocean water had to have been delivered later. Scientists suspect this was accomplished following collisions with millions of comets.

Another reason to go to and study 67P/CG in great detail, according to McCaughrean, is that comets also contain lots of organic molecules, things which are the building blocks of more complex molecules like DNA.

He and other scientists believe that it’s quite possible that comets not only delivered our water, but also the ingredients for life on Earth.

McCaughrean thinks 67P/CG will be a great target for study because, unlike many comets, its surface hasn’t been heated by the sun many times.

When a comet gets heated by the sun, “it gets processed. It gets kind of different on the surface to the way it is underneath,” he said.  He and his colleagues think Rosetta’s target comet will contain plenty of the primitive materials that it collected as the solar system was being formed.

On its way to rendezvous with the comet, Rosetta has made three fly-bys of Earth and one of Mars, while also encountering asteroids Steins and Lutetia along the way.

Once Rosetta reaches its destination, which should be in August, it will spend time orbiting the comet to gather crucial data. Then, in November, it will deploy the Philae lander, a small spacecraft on board, that will land on the comet itself. The Philae will use its 10 specialized instruments to sample and analyze material from the comet’s surface and subsurface.

The Rosetta Stone which is on display at the British Museum (Hans Hillewaert via Wikimedia/Creative Commons)

The Rosetta mission, which was green-lighted in 1993, is named after the famous Rosetta stone. Engraved on this important historic object is a decree issued by a group of ancient Egyptian priests around the year 196 BC.

The stone was inscribed with essentially the same text in three languages – ancient Egyptian Demotic, Greek and Egyptian Hieroglyphs. Scientists, with the knowledge of Demotic and Greek, were able to decipher the meaning of modern Hieroglyphs.

Some consider the deciphering of the Rosetta Stone as the pioneering effort in translating unknown languages. ESA scientists are hoping their Rosetta spacecraft, like the object it was named after, will help unlock the mysteries of how the solar system evolved.

Mark McCaughrean joins us on this week’s radio edition of “Science World” to talk about the Rosetta mission and Jan. 20 wake up call. Tune in (see right column for scheduled times) or check out the interview in the player below.