Last Saturday, ESA’s Rosetta space probe made a flyby just 6 kilometers (about 4 miles) away from the comet 67P/Churyumov-Gerasimenko, which is becoming more and more active because the approach to the Sun is sublimating its water ice. This maneuver is an important moment in the Rosetta mission for the possible analyzes but also because it starts a new phase in which the probe will move away from the comet for its passage closest to the Sun in August 2015.
The Rosetta space probe’s flyby is the culmination of a series of maneuvers that started on February 4, 2015 when it abandoned the orbit in which he was flying, about 26 kilometers from the comet 67P/Churyumov-Gerasimenko. Initially, Rosetta moved away from the comet until it was 142 kilometers (about 88 miles) away then it moved close again and to reach the minimum distance on February 14.
For ESA this flyby was an opportunity to make new exams of the most active regions of the comet 67P/Churyumov-Gerasimenko as the Rosetta space probe passed directly over them. The data collected will allow to find the areas where dust and gases emitted by the comet accelerate from the surface and understand how they change when they move away from it.
It had already been established that the surface of the comet 67P/Churyumov-Gerasimenko is particularly dark, one of the conclusions published in a special issue of “Science” dedicated to the Rosetta mission. During this flyby, Rosetta had the Sun behind it and this has allowed to take pictures with no shadows.
The comet 67P/Churyumov-Gerasimenko and consequently the Rosetta space probe are in the course of a period of about four weeks in which their orbit brought them more or less in opposition to the Earth. This means that the Sun is between them and the Earth, interfering with communications.
The consequence is that the transmission possibility between ESA’s control center and Rosetta are reduced. The transmission via ESA’s stations allow only 14 kbps, that of an analog modem from 20 years ago. The more powerful stations of NASA, which is collaborating in the mission, can communicate at 45 kbps.
This speed limits the amount of information that the Rosetta space probe can send in this period. Data from Saturday’s flyby on are coming slowly. In the coming days we can expect the first close-up pictures of the comet 67P/Churyumov-Gerasimenko, then new data analyzes. They’re definitely worth the wait!