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Phobos-Grunt's possible reentry path

Phobos-Grunt's possible reentry path
Phobos-Grunt's possible reentry path The map shows the approximate ground track of Phobos-Grunt for the period covered by the significant majority of estimates for its re-entry time. There was a very strong likelihood that re-entry would occur along this line, but it was not certain. As far as is currently known, the reentry was not observed. The yellow and red segments of line represent Phobos-Grunt in daylight; the purple segments represent the spacecraft's path in nighttime. If the re-entry was to have been seen visually, then it would have had to occur on the purple segments of track.

The RIA Novosti news agency originally quoted the Russian Ministry of Defence saying that re-entry was 1250 km west of Wellington Island, Chile at 17:45 UTC. This time and location was based on model results, not on any actual observations. Other published guesses from the Russian space agency and "unnamed experts" said that the location was not known, and Phobos-Grunt might have travelled as far as Brazil and the Atlantic Ocean. Spacetrack was slightly enigmatic, saying only that it had "Decayed Inside [the] Predicted Window," which was 16:59-17:47 UTC. The end of the Spacetrack window is marked as a red dot on the map. In the course of January 16, Roscosmos stated that the re-entry point was unknown but the event occurred between 16:40 and 17:10 UTC. This is the segment of track colored red on the map.

Taking all three of these statements together, then 17:45 is a plausible time, but is not the only possible time. In reality, a re-entry does not occur at a single point. A large re-entering object sheds fragments over an length of ground track with some burning up immediately and others taking time. Some can fall to Earth up to several tens of kilometers on either side of the track. All we can say at the moment is that the start of re-entry may have been approximately 16:45 UTC and that the event might have covered the ground as far as Brazil. © Robert Christy, www.zarya.info