The biggest gamble in the history of space: Landing on a comet

Posted Nov 8, 2014 by Karen Graham
Final preparations are being made for what is described as one of the biggest gambles in space history, coming up on Wednesday, November 12. After over 20 years of work, the goal of landing a probe, Philae, on a comet may soon be realized.
The Rosetta spacecraft.
The Rosetta spacecraft.
In 2004, the European Space Agency (ESA) launched its Rosetta spacecraft, sending it on a 10-year mission to catch a comet. On August 6, 2014, after years of zig-zagging between the orbital pull of Earth and Mars, the Rosetta made history, arriving at Comet 67P/Churyumov-Gerasimenko, referred to as "67P."
Rosetta's four billion mile journey through space has brought it to just 19 miles from 67P's position. On Wednesday, a robotic probe called Philae, a 220 pound working laboratory, will touch down on the comet's surface. The landing is scheduled to begin at 0835 GMT, and according to Sylvain Lodiot, head of flight operations, "Then it's a very gentle free-fall for the next seven hours."
ESA s control center
ESA's control center
As the time draws closer for the historic landing, news media and dignitaries from around the world will have gathered in the small town of Darmstadt, a mere 20 minutes from Frankfurt, Germany. In the heart of Darmstadt is the mission control center for the ESA. It is here that Paolo Ferri and his team will attempt to land Philae on comet 67P.
Comet 67P/Churyumov-Gerasimenko
Comet 67P/Churyumov-Gerasimenko, or 67P, was first observed by Klim Churyumov and Svetlana Gerasimenko, astronomers from Kiev, Ukraine, in 1969. They were working at the Alma-Ata Astrophysical Institute in what is now Kazakhstan. While studying photographs of the comet 32P/Comas Solá, Churyumov spotted what he thought was another comet-like object. Further study revealed that it was indeed a new comet.
View of comet 67P on November 4  2014.
View of comet 67P on November 4, 2014.
The comet, 67P makes regular visits to the inner solar system, circling the sun every 6.5 years as its path takes it between the orbits of Earth and Jupiter. 67P is one of a number of comets called short-period comets. Their orbital period is less than 20 years, and the orbit inclination is low. These comets are controlled by Jupiter;s gravitational pull, and hence the name given to this group, Jupiter Family Comets.
What scientists hope to learn from the Philae probe
Amazingly, the scientific instrumentation aboard the Philae only weighs 59 pounds, but it consists of 10 different analysers. One is an Alpha Proton X-ray Spectrometer (APXS), and it's probably the most important instrument on board. It will measure the "elemental composition" of the comet's surface.
Philae lander closing to the surface of a comet. Frame from the movie  Chasing A Comet – The Roset...
Philae lander closing to the surface of a comet. Frame from the movie "Chasing A Comet – The Rosetta Mission".
Deutsches Zentrum für Luft- und Raumfahrt
Other instruments include special cameras that will take high-resolution panoramic views of the surface and the other instruments. There is also a gas chromatograph, a magnetometer to study the comet's nucleus and magnetic field, as well as the SD2, a drill for taking soil samples. Multi-purpose sensors will measure the properties of the comet's outer surfaces.
With all the information that will be collected over the year the project is expected to last, scientists at ESA say the results collected are expected to rewrite the history of how the Earth was formed.
The landing site for Philae has been chosen.
The landing site for Philae has been chosen.
Success of mission will depend on peanuts
José Luis Pellon-Bailon is just one of the eight flight engineers responsible for Philae’s descent, and he says ESA has inherited a superstition from their counterparts at the National Aeronautics and Space Administration (NASA). He says the team is so well prepared they even know what they will eat on the historic day.
Mission control: A bee-hive of activity on Wednesday  Nov. 12.
Mission control: A bee-hive of activity on Wednesday, Nov. 12.
Believe it or not, it's peanuts. "We found out that people at NASA eat peanuts on the day of the special activity. In a mission that is problematic, they will always have peanuts on the table," says Pellon-Bailon. Ferri confessed they were vital to the mission, adding, "I'll also be wearing the same tie I wore when Rosetta launched ten years ago."