A quick summary of details on tonight’s reentry: where, when, how and more!

Note: All times subject to change

Where’s ATV now? Since undocking from Station at 14:46 UT yesterday, ATV2 has been in an independent orbit and is flying under the control of ATV-CC. ATV conducted a space debris avoidance manoeuvre last night at 18:30 UT, just a few hours after undocking.

Deorbiting: The deorbit will be accomplished by two engine burns. The first occurs at 17:06 UT (19:06 CEST) and lasts 609 seconds, while the second comes at 20:04 UT (22:04 CEST) and is planned for 849 seconds. All operations today are being managed in real-time, so the actual times and durations of any of the deorbit events may vary. Check the ATV blog regularly!

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ATV Reentry Scenario – video report credit: ESA TV

The Big Dive: Once the second burn is complete, ATV will plunge into the atmosphere on a very steep re-entry path over an uninhabited area of the Pacific Ocean. The vessel was designed to ensure safe, destructive reentry from the beginning. Further, the vessel will be commanded to burn its thrusters to put itself into a tumble, helping ensure that it is ‘caught’ by the atmosphere; this will also allow a precise, predictable reentry trajectory.

Once in the tumble, mission controllers at ATV-CC will begin receiving the vessel’s radio signals only periodically; subsequently, as the craft begins disintegrating, all radio contact will be lost.

Most of the vehicle will disintegrate and burn up at high altitude due to the enormous thermal and dynamic pressure loads induced by friction with the atmosphere at hypersonic speed. The high thermal loads will cause the fuel tanks (and remaining propellant) to explode at very high altitude – above 50 km according to simulations – without any risk of contamination at sea level.

Reentry Breakup Recorder: The REBR will ride down with ATV, recording data such as pressure, temperature and acceleration. It will fall free of the vessel as it disintegrates and, at an altitude of about 18km, make a satellite call to radio its data back to Earth. It will then drop into the ocean and does not need to be recovered (full details via Black box set to record ATV’s fiery death).

Final impact: The final predicted impact area is an uninhabited area of the South Pacific Ocean, east of New Zealand, west of Chile and south of French Polynesia.

It is very unlikely that anyone will see the reentry. In principle, if anyone were in the area, they could see the fireworks. But the impact area is an empty zone in the Pacific, far from shipping lanes and air traffic routes. ESA has informed New Zealand and Chilean authorities, who have issued formal warnings to aviation and shipping (referred to as NOTAM and NavAera alerts). ATV reentry will be monitored via telemetry received at ATV-CC, through to the time of destruction.

Didn’t we see ATV1 reenter? Yes – there was a joint ESA/NASA airborne observation campaign. Nothing is planned this time. More info including video and images via ESA and NASA.

What parts of ATV will survive to reach the surface, if any? Due to the high thermal loads encountered during reentry – friction will generate temperatures in excess of 1500 deg C – along the very steep trajectory selected for ATV, the majority of the debris resulting from the vehicle’s disintegration will be melted away.

Some debris will survive the reentry and will fall to sea spreading over an elongated elliptical area . Notably, the ATV’s engines (which are specifically designed to survive high temperatures) and the heavy, massive docking adapter may survive.

According to risk analysis performed at ESA/ESTEC and independent companies, only a limited number of fragments out of more than 700 may actually reach the sea. This is the main reason why the reentry is performed over a very large uninhabited area in the South Pacific Ocean.

The probability of causing damage or casualties is extremely low. The re-entry scenario has been extensively studied and the analysis results have been reviewed by the ESA Reentry Safety Review Panel and Review Board. This panel has given its go ahead for reentry