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Private propulsion, unable to send or receive data, the Russian space cargo Progress , which unsuccessfully tried to resupply the space station International (ISS) on April 28 began an inexorable fall to Earth.
Currently, seven tons of the ship unmanned are still in orbit around the Earth at an altitude of between 190 and 250 kilometers from our soil. It performs, out of control, some 16 laps around the earth daily. Due to the rotation of our planet, it is regularly above every region of the world except the poles.
Can we “fall on head “?
” It goes down slowly spiral because of the drag from the thin air at this altitude layer “ says Holger Krag, service space debris the European Space Agency. When it is “120 km altitude, the brake will be stronger this time and it will be a real fall” . When he is down about 80 kilometers, it will be almost the end. The vertical fall will last less than ten minutes
From this moment, it will be possible to see traces of light if the sky is clear. But “This is very different from meteorites” says Mr. Krag. “These are much more compact and are three times faster. They do not disintegrate completely before touching ground from which they create craters on the surface. Debris Progress will, themselves, a slower speed when they arrived. “
The disintegration of Progress will be such that few large pieces reach the surface of Earth, also covered by oceans 80%. It is also impossible to predict the timing of this event, which is expected to occur in about a week.
“It should be understood that all space objects ” fall “. But their speed is such that they make laps around the Earth. If you cast a pebble quickly enough, it will fall while returning in your hand after a tour “, adds Lionel Suchet, deputy director of the National Centre for Space Studies (CNES) in Toulouse. “Even the International Space Station ” grave “ and must enhance the regularly. “
A difficult to predict disintegration
These atmospheric flows are not uncommon. ” At CNES, we monitor a dozen returnees uncontrolled year “, says Mr. Suchet. “The novelty here is that it’s a big subject of some seven tons. This is about 10% [mass] of annual global revenue “, for its part Holger Krag.
” In a comeback controlled, we strongly putting a brake the ship to penetrate with a steep slope into the atmosphere and be as specific as possible to the point of contact. The South Pacific is usually the place we seek “, said Lionel Suchet. ” We achieve a strip 50 kilometers wide but can be many thousands of kilometers long. There are uncertainties in the state of the atmosphere, “, complete the specialist. In the case of Progress , so it is impossible to know when and how will this autumn.
The various sites giving the trajectories of various satellites, including Progress , are reliable for the moment because the braking is low. “ But their updates by radar data are less common than we have. So we can quickly correct the path and estimates “ says Lionel Suchet. The general public will have trouble following this live reentry.
No worries for life in the ISS
The reasons for the failure of this mission are not yet known. Impossible to say if this is the pitcher who has failed, or if it is the time of separation that problems arose; even if the cargo itself has had failures. Whatever the origin of the malfunction, contact and control have indeed been lost. And Progress is running abnormally on itself in five seconds.
As for the effects on life on board the international space station, there is little concern for Nothing. The six occupants of the ISS continued their experiences as if nothing had happened. Their reserves of oxygen, food and fuel are sufficient to hold at least until the summer. By then, the Dragon capsule to be launched on 19 June, should have fulfilled its mission.
In the worst case, nobody evokes the ISS occupants could evacuate the station using the Soyuz capsules docked to the station. These have heat shields avoiding disintegration by the dense atmosphere.
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