Phobos-Grunt Will Fall to Earth in January
Editor’s note: Dr. David Warmflash, principal science lead for the US team from the LIFE experiment on board the Phobos-Grunt spacecraft, provides an update on the mission for Universe Today.
This image is a montage of three separate images taken by the Viking 1 spacecraft during its flyby of Phobos on October 19, 1978. The large crater Stickney (on the upper left of the image) is over 9 kilometers in diameter.
It has been trapped in low Earth orbit for more than a month. So low is the orbit that it moves too fast to be contacted – unless controllers on the ground just happen to beam a signal at some unlikely angle. So short does its battery power last that it must be in sunlight while also in position to receive signals. Then, it must still have power to send telemetry back to the ground.
Even with these obstacles, Russia’s Phobos- Grunt probe did manage to communicate with the European Space Agency’s (ESA) antenna in Perth, Australia twice a couple of weeks ago, indicating that some of its systems were functioning. But subsequent attempts at communication have failed, despite the addition of ESA’s Canary Islands antenna at Maspalomas to the worldwide effort to reestablish control over the spacecraft.
Tracking of Grunt’s orbit has shown that its high point (apogee) and low point (perigee) continue to decrease, measuring about 289 kilometers and 203 kilometers in altitude, respectively, the last time I checked. Stories out of Russia in recent days describe how electrical cables found to be malfunctioning weeks before the launch were cut and connections re-soldered in a hurry to have the craft ready. Add to this the fact that the major sources on developments with the Grunt mission since its November 9 launch – Ria Novosti, the Russian Space Web, and ESA operations – all expect the craft to reenter Earth’s atmosphere in early January.
Taking all of this into account, it seems unlikely that Phobos-Grunt will ever respond to a signal again and say, “privyet’, much less turn on its engines and warp out of orbit. But there is an opportunity coming, a period when the odds that are stacked against the spacecraft may improve just a little.
|Phobos-Grunt and Yinghuo-1 spacecraft being encapsulated inside the nose cone for November 9 launch (Nov. 8 EST) to Mars and its tiny moon Phobos. Technicians prepare to seal the lander inside payload fairing at Baikonur Cosmodrome.Credit: Roscosmos|
Beginning Tuesday, December 13 at 17:00 universal time (UT) to Wednesday December 14, 23:00, Phobos-Grunt will be in sunlight throughout its entire orbit. It is not completely clear whether or not ESA will attempt to contact the probe during this period from Perth, or Maspalomas. Although attempts from Maspalomas were made throughout last week, the same attempts were scheduled to end on Friday, December 9. On the other hand, in a letter informing scientists participating in the mission that failure was the outcome, Phobos-Grunt science director, Lev Zelenyi, wrote: “Lavochkin Association specialists will continue their attempts to establish connection with the spacecraft and send commands until the very end of its existence.” Thus, despite the fact that the Russian Grunt team now is focused on the issue of reentry, we should not be surprised if they ask ESA to make one more attempt on Tuesday.
Will the greater than usual amount of sunlight allow the spacecraft’s communication system to work better than it usually does when it travels over tracking stations? Maybe yes, and maybe no. We should not get our hopes up that the craft will actually do anything but fall to Earth, and we’ve already discussed the possibility of the craft’s return capsule coming back in one piece.
But let us allow Phobos-Grunt its day in the Sun.