This week, the Rosetta spacecraft is scheduled to launch and launch a smaller spacecraft that will land on a comet in ten years. Prof. Akiva Bar-Nun from Tel Aviv University has an active part in the project, as well as the university's advanced comet imaging laboratory
Avi Blizovsky
Towards the launch of the Rosetta spacecraft to Comet Chermoyev-Grasimenko
On February 26, 2004, the Rosetta spacecraft will be launched to comet Chermoyev-Grasimenko, where it will arrive in August 2014. Part of the spacecraft will circle the nucleus of the comet for many months and the other part will land on the nucleus, dig into its ice and check its structure and composition.
At Tel Aviv University is the group for the simulation of comets involved in the Rosetta project of the European Space Agency in collaboration with the US Space Agency.
The Rosetta project is the cutting edge of comet research, the high points of which so far have been the close approach of the "Giotto" spacecraft to the nucleus of Comet Ley in 1986, the close approach of the "Stardust" spacecraft to the nucleus of Comet Wilad-2 in 2003 Photographing its face and returning dust from it for analysis in laboratories across the country, and now Rosetta staying many months near the nucleus of Comet Chermoev-Grasimenko, landing on its surface and investigating its structure and composition.
Comets - these are the most primitive bodies in the solar system, which have not changed since its creation 4.5 billion years ago. Today there is clear evidence (the most important of which comes from the comet simulation laboratory at Tel Aviv University) that comets brought to Earth about a third of all the water in the oceans and a great deal of the noble gases argon, krypton and xenon and the organic substances that led to the creation of life on Earth.
Prof. Akiva Bar-Nun from the Faculty of Exact Sciences, Department of Geophysics, has been a partner in the Rosetta project since its inception about 15 years ago, as a member of the scientific committee that decided what its scientific goals were, and as a member of the group of the University of Bern in Switzerland to test the composition of the gases released from the comet, during its heating, when it approaches the sun and creates the huge halo of water vapor, gases and dust.
This scientific collaboration resulted from the fact that the comet simulation laboratory at Tel Aviv University studied the ice of comets for 25 years. First in the device that creates tiny amounts of cometary ice, where you can test the physics and chemistry of cometary ice. Recently, the construction of the only device in the world that can create large amounts of cometary ice and study them was completed in our laboratory. This instrument had already provided results about the properties of cometary nuclei that had not been obtained before it. These results have already been published in the scientific literature.
Prof. Akiva Bar-Nun was interviewed by the Hadaan website and initially he was asked:
How did you come to be one of the initiators of the Rosetta Project?
"I have been working on comets for 25 years. Working with me on the project are mainly scientists from the European Space Agency and some from NASA."
Can you tell about the incarnations of the project?
Bar-Nun: "At first we wanted to land on the nucleus of a comet and dig inside, and bring a sample back to Earth. But there is a problem with digging in a body that has no gravity because when you push the drill in, the legs go up, so think of all kinds of other ways to dig and bring back a sample. Since we could not give the engineers an answer as to the mechanical strength of the face of the comet, it was ultimately decided not to try for the first time to return a sample to Israel, but only to insert devices into the ground, into the ice actually, and test them on the spot. It was decided that we would build a spacecraft that would do two things: on the one hand, a spacecraft that would stay above the comet for a long time and check all kinds of its parameters, and a second part would land on the surface of the comet and check it on the spot."
Did you replace a comet on the way?
"We changed a lot of comets. This project has already lasted more than ten years and each time we changed the comet because the conditions of the launch changed, and before the last one was Virtanen, then we had to send the Rosetta spacecraft with an improved Ariane 5 rocket, which had several failures, and then the European Space Agency decided not to risk the the spacecraft and send it with a normal Ariane 5 rocket which proved to be fine, then the target changed because it was a little later for Comet Chermoyev-Grasimenko and now we have to go up again with an improved Ariane 5 because another spacecraft is not ready in time and the agency insists that we launch with the rocket this. Let's hope it goes well."
What is known about this comet??
"As we know about many other comets. Every so often we know more and more. Now one of the Stardust spacecrafts has come close to Comet Wild-2 and photographed it very closely, much more closely than we saw the Halley spacecraft many years ago with the Giotto spacecraft and the ice that we see on the spacecraft is broken in a very special way, very similar to the shapes of the ice that we see today in our laboratory in the large simulation device of comets.
We also know a lot about the chemical composition of comets from many observations, mainly Hale-Bopp, and we think we will know a lot more when Rosetta reaches its target comet, which will happen in 2014."
It is a well-known comet, the very fact that it has a name indicates that it has been observed by the two honorable gentlemen and they are amateur astronomers, it means that it is bright enough to be seen. Of course, one must know exactly its route in order to approach it and study it."
Will you still be on active duty when it reaches its destination in 2014?
"At the time, several years ago, there was a question in the European Space Agency about when to launch the Rosetta spacecraft, because the European Space Agency had four junction points, it had to decide on the order of priorities. At that famous yeshiva I looked at the heads of all the researchers and most of them already had shiva hair back then. I suggested to them that if they put it off too much, when we get to Shavit we won't remember at all what we came there for and we certainly won't look at the results. And really with the same result it was decided that we would be earlier compared to other spacecraft of the European Space Agency. I really hope that there will be no problems with this launch, and then the spacecraft will actually travel on its way for many years until it reaches the comet."
Long-term planning is rare?
"Not so. For example, the Galileo that was launched to Jupiter was started to be planned in 1969 and in the end it was also delayed because of the Challenger disaster and it operated in the Jupiter area in the late nineties and early XNUMXs. Big projects take a very long time. Sometimes there are delays."
Towards the launch of Rosetta on the European Space Agency website
