If rescue fails, Fobos-Grunt will reenter soon

As new attempts to contact the probe failed, the future is looking increasingly grim for Fobos-Grunt (aka "Phobos-Grunt" and "Phobos-SOIL"), the Russian space probe launched on 8 November that should have gone to the Martian moon Phobos for a sample return mission, but instead got stuck in Low Earth Orbit.

The probe is currently stuck in a very low orbit measuring 207 x 339 kilometer after it's propulsion unit apparently failed, failing to lift it into a GTO (and from there an interplanetary trajectory):

If the probe isn't revived in due time - and the Russsian operators are still frantically trying to do so - it is doomed. With an orbit at this low an altitude, it is a short matter of time before it comes down again - another case of an imminent uncontrolled reentry of a very large satellite (over 13 metric tons, including the fuel). How much fuel is onboard is not clear to me: different media sources quote quite different amounts, but all amounts quoted are in terms of several tons, with several sources settling for 7 tons (see also here).
As pointed out here by Anatoly Zak, seizable chunks of the probe could survive reentry, and survival is certainly expected for the actual Fobos sample return capsule (which was designed for reentry).

Reentry estimates

Estimates of when Fobos-Grunt  will come down are a bit complicated. Ted Molczan has noted that over the past day, the orbital evolution was unusual - Ted points out that if the last two orbit releases are not faulty (a  possibility), it means that either the probe is manoeuvering (which from all the negative statements by the Russians in the press seems unlikely) or - more likely - has started to vent fuel since yesterday. As a result, it might have gotten a very mild orbital boost (the leaking fuel acts like a small rocket engine).

Before this unusual behaviour started, orbital elements 11314.14749491 to 11314.77184893 and Alan Pickup's SatEvo software with current solar activity levels suggested a nominal reentry time no later than early January 2012. SSC meanwhile predicts reentry for November 26th, 2011. The current unusual orbital evolution - if real - might change things a bit, but eventually it will come down.

This means it will likely come down somewhere over the next few weeks or months if the operators cannot revive it over the next two weeks. With an orbital inclination of 51.4 degrees, it can come down anywhere between 51 N and 51 S latitude.

There has been a call out to observers to observe the probe - it's brightness behaviour can yield clues as to whether it is starting to tumble, e.g. because of the suspected fuel venting. So far, observations by Brad Young and Michael Murphy from the US suggest the probe is stable in brightness with no sign of tumbling (see here and here).

Unfortunately, the probe is currently not visible from NW Europe where I am located: it makes passes near midnight, completely in shadow.

Footage of a Fobos-Grunt pass

The footage above was shot by me this evening, and shows the Russian space probe Fobos-Grunt (aka Phobos-Grunt or Phobos-Soil), 2011-065A.

Fobos-Grunt was supposed to go to the Martian moon Phobos for a sample return mission. Instead it got stuck in a Low Earth Orbit, due to a rocket engine malfunction. It is now expected to re-enter into the earth atmosphere early to mid  January.

This footage was shot from my girlfriend's appartment at the second floor of our appartment building: only there was I able to point low enough in the sky. The footage shows the space-probe at an elevation of less than 15 degrees over the western horizon. It enters earth shadow at the end of the 50 second clip.

Observing Fobos-Grunt on 30 November

It was clear this evening, and the Russian Mars/Phobos probe Fobos-Grunt (2011-065A) stranded in Low Earth Orbit made two visible passes which I both observed.

The first pass was in deep twilight, 16:08 UT with the sun only 5 degrees below the horizon. The sky was still bright blue and only the brightest stars (Altair and brighter) were visible. Nevertheless, Fobos-Grunt was easily visible by the naked eye, becoming clearly brighter than Altair around and after culmination at 45 degrees elevation in the south. It was very fast and showed no sign of brightness variation. A very fine view!

It made a second pass at 17:40 UT, plunging into the earth shadow at 25 degrees due west. I captured it on a photograph when it was at 20 degrees elevation, close to alpha Oph (brightest star in the image):

click image to enlarge

The lens used was the SamYang 1.4/85 mm and because of the low elevation and city environment, I kept the exposure short to 5 seconds. Due to a different phase angle compared to the earlier pass, the space-probe was faint, near +4.

I also tried to video it again like two nights before (see video in my previous post). This time less succesful, due to a case of Murphy. A cable came lose just at the moment supreme, and in the haste to attach it again, the camera was moved and then pointed to the wrong star.....

[Updated] Summary of Phobos-Grunt reentry predictions as off 14 Jan, 13:00 UTC

Current predictions by various sources for the reentry of the failed Russian Mars probe Fobos-Grunt all still have a very large uncertainty window. Therefore, it is still impossible to provide any realistic statements about the when and especially where the reentry will happen. Suggestions in the press such as these only demonstrate a continuing and thorough misunderstanding of the whole issue among some journalists.

Perhaps as a result of this, USSTRATCOM has changed the way it presents it's Fobos-Grunt reentry predictions. While for other objects they still use the classical TIP format (time with uncertainty interval, and position at the nominal time), they altered the presentation for F-G: they only list the uncertainty interval, without positions or nominal time. Given the way that TIP messages were taken completely out of context and misinterpreted in the press recently (e.g. the notorious and utterly misinformed Novosti-RIA publication here), this is all a very understandable precaution.

A summary of the current predictions (round-up of predictions at 14 Jan, 13:45 UTC. Listed are: source; time/date prediction was issued; predicted time plus uncertainty interval, or uncertainty interval only):

USSTRATCOM (13  Jan 15:30 UTC): 15 Jan 08:25 - 16 Jan 03:37 UTC
Harro Zimmer (13 Jan 11:51 UTC): 15 Jan 17:05 +/- 3 hrs UTC
Ted Molczan (14 Jan 08:35 UTC): 15 Jan 22:31 +/- 8 hrs UTC
Celestrak (T.S. Kelso, 14 Jan 11:00 UTC): 17 Jan 10:04 +/- 1 day UTC
AeroSpace Corp. (13 Jan 10:40 UTC): 15 jan 17:52 +/- 14 hrs UTC
Roscosmos (14 Jan UTC):  15 Jan  21:51 17:51 UTC (no uncertainty window listed)

[added 15:45 UT, 14 Jan] My own estimate, using Alan Pickup's SatEvo and the current space weather (F10.7 cm flux) and the Jan 14.54 orbit, is for 15 Jan, 21:50 +/- 7 hrs UTC.

PLEASE take note of the large uncertainty windows on all these predictions! The uncertainty amounts to many revolutions of F-G around the Earth, so it is impossible to even indicate a Continent or Ocean (as some media sources do) where F-G will end up, at this moment.

Most of the predictions favour the 2nd part of Sunday Jan 15th.

Gearing up for the Phobos-Grunt reentry

We are in for an interesting weekend, as the failed Russian Mars probe Phobos-Grunt is experiencing it's last days of existence. Gradually having come down over the past two months, it is expected to re-enter and burn up (but perhaps not completely) in the Earth atmosphere on Sunday or Monday.

Several days before the re-entry date, it is still not possible (whatever some news outlets erroneously write) to pinpoint when and where it will come down. At the moment of writing (early Friday), the SSC prediction amounts to a still over a day wide window between 15 Jan 02:40 and 16 jan 07:40 UTC. Harro Zimmer's latest prediction is for Jan 15 between 9:00 - 15:00 UTC. Both predictions encompass multiple revolutions around the earth. Please note: all these time windows can still shift, depending on actual developments in space weather (solar activity)  and other factors.

Below video has been posted here before, and shows a Fobos-Grunt pass filmed by me from Leiden, the Netherlands, on November 28:

Summary of current Phobos-Grunt reentry predictions (15 jan 11:00 UT)

Summary of current Fobos-Grunt reentry predictions, round-up of predictions compiled at 15 Jan 11:00 UTC:

USSTRATCOM (14 Jan 20:30): interval 14:52 - 19:40 UTC
Harro Zimmer (15 Jan 07:10): 17:49 +/- 45 m UTC
Ted Molczan (15 Jan 04:59): 20:39 +/- 3 hrs UTC
Aerospace Corp. (15 Jan 06:25): 19:21 +/- 3 hrs UTC 
Roscosmos (14 Jan):  18:36 UTC (uncertainty window not stated)

Listed are: source; time prediction was issued (UTC); predicted time and uncertainty interval, or predicted interval.

My own current prediction, using Alan Pickup's SatEvo, current F10.7cm flux and 09:21 UT epoch orbital elements:  20:07 +/- 2 hrs.

PLEASE take note of the still large uncertainty intervals. As yet, it is still impossible to realistically say where it will come down.

Summary of 2011 observations

As the year is closing, it is time for a summary of the observations conducted in 2011.

Compared to the previous two years, 2011 saw slightly more observing nights, a larger number of  classified objects tracked, but a slightly lower number of positional estimates done:

Number of observing nights: 87
Number of obtained positions:  883
Number of classified objects tracked: 43

For 2009 and 2010, this were respectively: 77, 953, 32 and 78, 1084, 39

In the second diagram above, it can clearly be seen that the spring and late summer were very good (many clear nights), while winter, and especially December, were very poor.

The following tables give a summary of the objects observed (with the "obs" column refering to the number of positions obtained on the object):

(click tables to enlarge)

Just for fun, I plotted all obtained positions on an RA/DEC map:

click diagram to enlarge

New at SatTrackCam in 2011:

2011 saw several new additions to the equipment:

New lenses - new lenses added to the repertoire were the very fine SamYang f1.4/85mm and a Canon EF 2.0/35 mm. The SamYang allowed to target fainter objects in LEO and MEO, going clearly deeper than the EF 2.5/50 mm normally used on brighter objects in LEO. It's FOV is still large enough to capture full trails.
The Canon EF 2.0/35 was added to target fast moving objects in LEO such as objects near decay, Soyuz and Progress, and Keyholes in perigee passes. It has a similar aperture as the 50mm lens but a wider FOV.

Video - Video finally did it's entry at SatTrakCam Leiden in late 2011. The equipment consists of a sensitive WATEC 902H camera that can be equiped with a number of lenses (including the above mentioned Canon EF 2.0/35 and the SamYang 1.4/85). A GPSboxSprite2 time inserter from BlackBoxCamera in the UK is used for the imprint of accurate time signals, and the video feed is recorded on a HDD recorder.

Remote telescope - I have used remote rentable telescopes for some time for my work on asteroids. Starting mid-2011, I am also using them on satellites. The telescopes used are part of the SSON network and consist of a 37-cm and 61-cm Cassegrain located in California and Arizona. These received COSPAR station codes 8231 (Winer obs, MPC code 597) and 8438 (Sierra Stars obs, MPC code G68). I use them to target geostationary satellites visible from the western part of the USA. Two notable targets repeatedly imaged were the new SBIRS Geo 1 (11-019A) and the enigmatic Prowler (90-097E).

Observational highlights:

A few observational and other highlights of 2011:

Nanosail-D - This experimental NASA solar sail put on a fine show during late spring and summer. A study was made of the brightness variation of this object. See various posts here.

The last Space Shuttle missions - The truely last one was not observed, but the last flight of Discovery was imaged several times.

Spectacular IGS 1B flare - IGS 1B is a Japanese spy satellite that failed in 2007, will reenter in 2012-2013 and probably still has some fuel onboard. When I posted on the latter on this blog, this generated some interest, even from the White House.
On  September 2nd, I observed a brilliant flare produced by this satellite, one of the best satellite flares I have ever seen.

UARS and ROSAT - the uncontrolled reentries of these two satellites generated a lot of attention. ROSAT was actually observed twice by me shortly before its reentry, see here and here.

Fobos-Grunt - This Russian probe launched in November should have gone to Mars and the Martian moon Phobos for a sample return mission. A rocket engine failure however got it stuck in Low Earth Orbit, from which it will reenter mid-January. I observed, photographed and even filmed it a number of times.

Andre Kuipers to the ISS - on December 21st, a Soyuz with Dutch astronaut Andre Kuipers was launched for a six-month mission to the ISS. Just before the end of the year, I finally could see the ISS with Kuipers on board pass over Leiden and film it (between launch on December 21 and the sighting on December 30th, it had been very bad weather).

Andre's Soyuz 3rd stage decay - Due to untimely cloud cover I did not observe this event myself, but was involved in the identification of it. The spectacular decay in the evening of December 24th was seen by many people in the east, central and southern parts of the Netherlands (where it was clear, unlike in Leiden), as well as from Germany and France.
Ralf Vandeberg (B), Josep Remis (F) and me (NL) independantly were the first to identify the slow fragmenting fireball with the Soyuz 3rd stage used in the December 21 lauch to the ISS, disseminating our identifications on mailing lists, twitter and blogs within half an hour after the fireball apparition. Read more here.