Two months ago hardly anyone outside a narrow circle of astronomers has ever heard of a comet named 67P/Churyumov–Gerasimenko. But on Nov. 12, the comet topped the headlines. On that day, a Rosetta probe launched by European Space Agency successfully deployed a robot lander on it, making it the first time in history when anything landed on a comet’s surface.
Ukraine had something to do with this astronomy breakthrough. Ukrainian scientist Klim Churyumov discovered the comet in 1969 with his assistant Svitlana Gerasimenko.
Churyumov, 77, is now retired and lives in Kyiv. He believes that the Rosetta mission is a huge step forward in astronomy, because scientists can explore the comet closely and observe how it changes when it gets closer to the sun.
Even in retirement, Churyumov remains extremely passionate about his specialty. He can speak about comets for hours. He also writes books for children and is an editor of scientific magazine and the head of the biggest planetarium in Kyiv.
Churyumov remembers his discovery well and says it was “almost a detective story.”
In 1969 he and his assistant went to Almaty astrophysical observatory in Kazakhstan to conduct surveillance of periodic comets. With a laugh, Churyumov remembers that they basically received the order from authorities to discover a new comet.
“That was a common practice in Soviet times,” he says.
In Almaty, Churyumov photographed a comet but thought it was an already known one, called Comas Solá. After he returned to Kyiv, he found out that the orbit of the comet on the pictures is too different from the Comas Solá. Then he knew he discovered a previously unknown comet.
Churyumov says that the European Space Agency chose his comet for a Rosetta mission because it has short-period orbital. That means that its orbit is quite small and scientists can define it more accurately.
“It takes the comet only six and a half years to take a full circle around the sun,” Churyumov says.
Also, the comet was passing near the earth when scientists planned Rosetta’s launch.
The Rosetta probe was launched in 2004 and reached the Churyumov–Gerasimenko comet after a 10-year journey. No existing rocket is able to deliver a spacecraft that weighs three tons directly to the destination point. That’s why Rosetta functions rather like a satellite circling the sun almost four times before it finally meets the comet.
Churuymov explains that this method is called “gravity maneuver” and that, in this way, Rosetta used a minimum of fuel. Almost all of the work was done by gravity and scientists just changed the probe’s trajectory when it came close to the comet. Then the space agency could see the exact look of the core and choose the best area for Rosetta’s Philae lander to touch down. The lander collected the samples of ground, gases and atmosphere there.
But not everything went smoothly. Philae bounced two times before it managed to land on the comet because its hooks didn’t stick the spacecraft to the surface. The lander has provided scientists with unprecedented images of surroundings. Soon the battery ran out and Philae has remained inactive. Scientists still hope to “wake it up” when the comet will go closer to the sun as the lander has solar batteries.
Meanwhile, Rosetta continues its flight around the comet and continues to take its pictures. The first pictures of the comet were released on Nov. 15.
The mission is expected to be over in December 2015, when the European Space Agency will lose the connection with Rosetta and it will fly away into space.
The analysis of the comet samples has already brought important results. The samples showed that the water on the comet is significantly different from the water on earth, which calls in question a popular theory that comets brought water to earth.
Churyumov believes in this theory, but admits its just a hypothesis and that there are still many things unknown about comets and space.
Kyiv Post staff writer Anna Yakutenko can be reached at [email protected].
