Leonard David's INSIDE OUTER SPACE

These three images of comet Churyumov-Gerasimenko were acquired by the OSIRIS camera on board the Rosetta spacecraft on July 29, 2015. In the first image the outburst is not yet visible. Eighteen minutes later, the camera captures an enormous gas outflow. The third image displays only the weak remains of the jet. The images were acquired from a distance of 115 miles (186 kilometers) from the comet.
Credit: ESA/Rosetta/MPS for OSIRIS Team/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The European Space Agency’s Rosetta orbiter has been imaging comet Churyumov-Gerasimenko – watching the celestial wanderer hurling dust and gas into space.

All that action is prelude to the comet making its closest point to the Sun in its orbit, the perihelion, on August 13.

According to experts at the Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), roughly 220 pounds (100 kilograms) of the comet’s mass are disappearing into space per second. In its approach to the Sun, the comet’s frozen ice has been heating up and turned into gas, which has dragged along some dust with it as it spills out into space.

Powerful outburst

The instruments on the ESA Rosetta spacecraft succeeded in imaging and analyzing the most powerful outburst yet, from a distance of roughly 115 miles (186 kilometers).

“The activity of the comet will likely increase slightly in the days after perihelion,” says Ekkehard Kührt, a researcher at the DLR. “We are now excited to see how it will evolve in the coming days and weeks.

“The activity will depend mainly on where the active areas are with respect to the comet’s seasonal cycle, Kührt, adds in a DLR press statement. “With the mission, we are for the first time accompanying a comet and monitoring its development for such a long period of time.”

How’s Philae?

The Philae lander, deposited on the comet by Rosetta, is along for the ride.

Rosetta’s Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) camera shows the spot (marked with a red circle) on Comet 67P/Churyumov-Gerasimenko, where the massive gas eruption occurred on July 29, 2015.
Credit: ESA/Rosetta/MPS for OSIRIS Team/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

However, Rosetta’s current trajectory is not favorable for establishing communications with the landed probe.

“The orbiter, which is a kind of relay station to Philae for us, is flying over the southern hemisphere, which is particularly active,” explains DLR engineer Koen Geurts, Technical Project Manager for the Philae lander.

“From August 11, Rosetta will once again be flying over latitudes where communication with Philae would be possible,” says Geurts. But the great distance between the orbiter and the comet could complicate communication with the lander.

The last contact between Philae and the team at the DLR Lander Control Center in Cologne took place on July 9, 2015.

On the job

To make sure Philae could still carry out its job on the surface, even without communication with the ground team, the DLR engineers tested some commands on their ground model in Cologne.

These commands were then sent “blind” – in other words, without a response, to Philae.

In the event that the lander receives these commands and executes them, it will initiate a sequence in which various instruments will be operated and the data stored until contact is resumed.

Rosetta was launched in 2004 and arrived at Comet 67P/Churyumov-Gerasimenko in August 2014. It is the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander to its surface, the Philae probe, in November 2014.

One Response to “Churyumov-Gerasimenko and the Jets!”