Saturday, January 14, 2017

Successful Mission : relive the first exit into space Thomas Pesquet – Science and Future

The first output in the space of the French astronaut Thomas Pesquet, Friday, 13 January 2017, alongside his american colleague Shane Kimbrough, went off without a hitch and the mission has been completed more quickly than expected, 5 hours and 58 minutes. The two men have stopped the internal batteries of their dive at 17.20 GMT. Their main mission was to make connection of three lithium-ion batteries essential for the proper functioning of the electrical installations of the international space station (ISS). A part of the operation had already been conducted by the robotic arm of the station, and during a previous spacewalk, conducted earlier this year by two other members of the crew : the american astronauts Shane Kimb rough and Peggy Whitson. The spacewalk was filmed and streamed live by Nasa.

Sébastien Rouquette, project manager for parabolic flights at CNES in Toulouse, we had described the place, the dangers and pitfalls of this day pretty ordinary. The previous week had been largely devoted to the preparation of the exit 39, and especially to the tests on the EMU (extravehicular mobility unit). This scuba 200 kg is truly a mini spaceship, equipped with air-conditioning, systems distribute the oxygen, remove the heat, the humidity, the CO2, protect from cold, sun and also marries the human physiology. It is easy to handle, but stiff enough to be protective. The tests have taken hours and hours of work in the ISS, because the outputs remain risky experiments. This is to check that all sealing systems, hydraulic, fluid distribution, recycling, etc work perfectly.

Find the steps in the output below : (hours French)

Just after breakfast, began the dressing of the diving bell and the verification of its systems. We proceeded to the start of the EMU, to its drain, its cleaning and verification of the “fit check” : the diving bell is it tuned to the size of the astronaut ? In fact, there are two suits in the airlock (there are four in total in the ISS), which is shared by three users (Shane Kimbrough, Peggy Whitson and Thomas Pesquet). If one of the suits is already set to the size of Shane, a result of the EVA (Extravehicular activity, or spacewalk), which took place a week ago with Peggy, it was necessary to set the second to the size of Thomas. This is the fourth EVA for Shane and the first for Thomas. For Peggy, it was the seventh last week !

The two astronauts begin to breathe pure oxygen. It is a procedure that could be described as “scuba diving” reverse. During a dive, it descends from a treaty to a medium to high pressure, but it is necessary to go back through levels to avoid accidents depressurization, during which a bubble of nitrogen in the blood can dilate and cause a fatal accident. In space, one can breathe pure oxygen before exiting into the vacuum to avoid bubbles of nitrogen in the blood that is dilateraient in the phase of depressurisation. In other words : the astronauts are making their bearings before the exit into space !

There is the depressurization of the EMU.

The diving bell is now autonomous and we can make the vacuum in the sas.

If everything is “nominal”, the lock opens. It is the commander of the ISS Shane Kimbrough is released first, followed by Thomas Pesquet. This last is directed to the HTV6, the cargo vessel japanese who carried the batteries and their supports in orbit and is docked to the ISS, while Shane has prepared the tools, left to the outside during the previous EVA, on the work platform. This is the only time where the two men were separated, before Shane joined Thomas near the HTV.

Their travels in the vacuum of space are similar to those of the climbers. As in climbing, they are equipped with a safety harness, straps and hooks, double security, it is necessary to take in hand a certain way to activate the trigger and engage the hook on the handrail. There are two hooks, because the handrail is at junction points. As acrobranche, it is always necessary to guarantee her life line ! Because if the astronaut deviates too far from the station without being attached, he may not be able to come back. However, the EMU is equipped with the system SAFER (Simplified Aid For EVA Rescue), which allows them to redirect them back to the station.

It took them several hours to replace the last three batteries of the ISS. These, as well as their supports, must be secure. Like all tools, that must be attached. When an object escapes from you in space, it is lost and becomes a threat. In June 1965, the American Ed White has lost, during a spacewalk, his surgant that he had removed to be able to manipulate a tool. It has become the most dangerous in orbit, because it moves at the speed of 28 000 km/h and with time it has changed orbit and trajectory and can reach the full force of an astronaut in EVA. Imagine the slap destructive that would receive that which would be hit by such an object, capable of crossing high-speed your scuba diving gear…

Then, the astronauts have conducted operations additional : draw a network of wiring up the solar panels, changing a lamp to illuminate a part of the ISS and back of the head shields is currently on node 3 (as a component of the junction between two modules). Finally, they made the photos of a cooling system to be defective, in view of a subsequent repair. During these outings of several hours, the astronauts are able to drink through a pipette which is installed inside the diving bell and eat energy bars. There is even a finger artificial installed in the helmet which allows them to scratch the face if they feel the need.

Thomas Pesquet returned the first to the ISS, before the captain Shane Kimbrough.


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