The stone and Rosetta – A flair of moon landing
It does not happen too often that a scientific event makes it into the headlines of the daily press. As fascinated as in the prime times of the Football World Cup we have been in the last few days following the touchdown of “Philae”, the landing device of the spacecraft “Rosetta”, on the comet Churyumov-Gerasimenko–referred to as “Tschuri” by researchers and as of this year the media. On 12 November 2014 the big event finally occurred: For the first time in history a man-made machine landed on a comet, more than 55 years after an artificial missiles landed on the lunar surface (the Soviet Lutnik 2 on September 13, 1959) and more than 45 years after the first human landed on the Moon.
This has by no means been as easy a matter as many “Armageddon” movie fans might believe, as the following illustrates: With 100 kg inertial mass only a gravitational force, which corresponds to 10 g on Earth, acts on Philae. And furthermore, because of the non-circular shape of the comet this force varies strongly (an effect that can be observed in much weaker form on the much rounder earth). Thus the main concern of the responsible scientist had been that the probe would bounce back like a billiard ball when hitting the comet.
This apparently is exactly what happened, as a portion of the recoil jets did not work and in addition the designated harpoons and ice screws to fix the device on the ground were not active. The lander thus jumped up again at first contact. Overall Philae landed three times on the comet before it came to a standstill about a mile away from the planned landing point. The responsible scientists in the center of the ESA (European Space Agency) and DLR (German Aerospace Center) reacted with big sigh of relief, when the probe sent the desired radio signals and the connection was good, according to ESA. But the situation was not quite that stable, the scientists added. And just a day later many of their fears were confirmed: The unforeseen shady landing area on the comet made it difficult to recharge its batteries. It was running low on batteries which threatened to cut off the possibility of collecting interesting data on the comet. In addition, all operations had to be done with great caution, as the lander stands only loosely on the surface of the comet. With a thoughtless movement it could easily be pushed out back into space. And in fact, again one day later the probe stopped sending data. But the scientists have not given up their hope that with improved sunlight the batteries will recharge themselves.
The entire project has not been a cheap affair. The mission, which began in 1992 cost a total of one billion euros. That is a lot of money to land a refrigerator sized machine on a comet. Inevitably the question arises, what all those euros were spent for. The scientists hope to draw conclusions on the chemical and isotopic composition of the early solar system. They also want to know if there are any amino acidson the comet and if so which direction they have. These are known to form the basis for the origin of life. These studies thus involve fundamental questions of our existence.
With no modest intention the comet chaser was named after the Egyptian port city of Rosetta and the lander after the island of Philae in the Nile. In those sites historical sources were found that constituted milestones in the decipherment of ancient Egyptian writings: the Rosetta Stone and an obelisk on the NiIe island (therefore on board the spacecraft is also a Rosetta Disk). We can hope for similar scientific breakthroughs, the name of the mission suggests.
But what does that give us in practical terms, many of us might ask. Had in a similar way people asked that question hundred years ago thereby questioning the basic scientific research on the structure of the atom, we would today still solve our computing tasks with abacus and logarithmic tables. Resulting from this basic research quantum mechanics evolved which constitutes the basis of pretty much every key technology of the 20th century, and many of those in the emerging 21st.We do not know what will come out of today’s basic research, which future key technologies might emerge as a result of them. Whether the (expensive) exploration of a comet or the (even more expensive) hunt for elementary particles will lead us there, we cannot know better as people were able to judge the study of atoms 100 years ago. Only the Armageddon fans know for sure: If ever a comet threatens to destroy our planet, the Rosetta mission was worth every of its 100 billion cents.