Fobos-Grunt

Launch data: Designation  37872 / 11065A Launch date  08 Nov 2011 - 20:16 UT Launch site  Baikonur, LC-45/1 Launch vehicle  Zenit-2SB (Fregat-SB) Mission  Phobos Flyby, lander & soil sample return Earth orbit on Dec 17, 2011: Perigee / Apogee  198 x 273 km Inclination  51.4 deg Period   min

Fobos-Grunt transat stack, with lander on top

Spacecraft data: Prime manufactor  Lavochkin NPO Operator  Russian Federal Space Agency Mass at launch  13505 kg (with fuel) Payload Mass  50 kg Basic shape   Dimensions (m)   Stabilization  3-axis Total mission duration  apptox. 34 months  Return capsule Mass  7 kg Sample Volume  100 cm³ Sample Mass  0.2 kg  Ascent Vehicle Dry Mass  139 kg Propellant Mass  135 kg Thrust Specific Impulse  3002 m/s Thrust  124.6 N Solar array  1.4 m² Attitude Accuracy  0.5 deg Angular Velocity  0.005 deg/s Tranmitter power  15 W  Cruise Module Mass  550 kg Solar array Panels  2 deployable fixed solar arrays - 10 m² Attitude Accuracy  0.5 deg Angular Velocity  0.005 deg/s Tranmitter power  40 W

Overview of planned trajectories: 1. Baikonur Launch 2. First burn 3. Spent fuel tank ejected 4. Second burn (Departure to Martian system)

Decay: Descent date:  15 Jan 2012 - 17:38 UT Lifetime:  days

Fobos with solar arays deployed

Descriptions:

• Phobos-Grunt is a robotic space probe built on the modular principle.
• It includes:
  • sustainer propulsion system with a pack of strap-on propellant tanks;
  • adapter truss;
  • cruise module that includes a propulsion system and a soil sampling complex;
  • ascent vehicle that includes a propulsion system and a return capsule.
• Also tucked aboard is China’s first interplanetary mission to Mars called Yinghuo-1. The 110 kg orbiter will study the Red Planet’s magnetic and gravity fields and surface environment from orbit for about one year.
• Due to some instrument installation requirements, the Phobos-Grunt has no autonomous instrumentation bay, and the science instruments are mounted on the probe’s structural elements.

Mission details:

• The Russian Fobos-Grunt mission's objectives are to collect soil samples from Phobos, a satellite of Mars and to bring the samples back to Earth for comprehensive scientific research into Phobos, Mars and Martian space.
• Fobos-Grunt is the first Russian-led interplanetary mission since the failed Mars 96. The spacecraft is also carrying the Chinese Mars orbiter Yinghuo-1 and the tiny Living Interplanetary Flight Experiment funded by the Planetary Society.
• The Fobos-Grunt probe took off at 2016 UTC (3:16 p.m. EST) on Nov 8, 2011 and reached a 206 x 341 km x 51.4 deg Earth parking orbit, but the solar orbit insertion burns did not take place. The probe separated from the Zenit-2SB41.1 rocket's second stage and remains in low earth orbit attached to its MDU propulsion unit (similar to the Fregat stage). Attempts by ground control to contact the vehicle have been unsuccessful, and the probe, with an approximate mass of 13500 kg, is expected to re-enter towards the end of the year.
• The Fobos-Grunt mission was intended to return a sample of the Martian moon Phobos to Earth. The main spacecraft is attached to a Fregat-related propulsion system consisting of the MDU main propulsion system (around 735 kg dry with 7015 kg of propellant) and the SBB drop tank (with a further 3000 kg of propellant). The MDU was meant to make a first burn to raise apogee to 4250 kg, release the drop tank, then make a second burn to 17500 km and, some days later, a third to solar orbit insertion.
  In August 2012 it would have also performed the Mars orbit insertion burn. At this stage the MDU would have separated from the main spacecraft, together with a truss structure and the 115 kg Chinese Yinghuo-1 sub satellite; these three objects would have been left in a 900 x 77000 km equatorial Mars orbit. The Fobos-Grunt PM (Pereletniy Modul', or cruise module) would have made two major burns to enter a 9900 km circular Mars orbit, completed a rendezvous with Phobos, and after some months of close observation would have landed on its surface. A surface sample would then have been transferred to the 7 kg SA (descent capsule) which would have been launched to Mars orbit by the VA (vosvrashchaemiy apparatus, return module). The VA would have made the trans-Earth insertion burn and controlled approach to Earth, separating shortly before the SA performed entry and landing, which would have occurred in August 2014.
• This was an extremely ambitious mission given the limited resources (and underpaid scientists and engineers) of the IKI space science centre and the Lavochkin company which built the vehicle and managed the mission.
  The last fully successful Russian interplanetary mission was Vega-2 in 1985-86, followed by a partial success by Fobos-2 in 1988-89. The Fobos-1 and Mars-96 missions were failures. With this record, the IKI/Lavochkin team, which have had a monopoly on Russian/Soviet interplanetary exploration since IKI's formation in 1965, would have been better advised to attempt a much more modest probe.
• The mission might be saved, if the probe can be commanded to fire the propulsion module within three days, after which the probe will be running out of battery power.
• If it succeeds in achieving these aims, Fobos-Grunt will become the first spacecraft to return a macroscopic extraterrestrial sample from a planetary body since Luna 24 in 1976, and the first successful Russian interplanetary mission since 1986. However, if it does not succeed in leaving Earth orbit, the 13.2 metric tonne spacecraft may undergo Earth re-entry in the near future.
• On Nov 22, 2011 ESA reported a successful contact with the Fobos-Grunt probe stranded in low Earth orbit, using its ground station in Perth. Further contacts were made on Nov 23/24. However, later contact attempts did not succeed and it now appears that the probe will reenter the Earth's atmosphere in mid-January. On Dec 17, Fobos-Grunt was in a 198 x 273 km x 51.4 deg orbit.

Fobos-Grunt re-entry:

• At 1636 UTC on Jan 15, 2012 FG's orbit was 112 x 124 km x 51.4 deg.
  According to the Russian `space control network' the spacecraft was expected to have reentered about 1745 UTC on Jan 15, over the Pacific Ocean. Other reports from the Russian `ballistics' calculations suggested a slightly later reentry predicted at 1759 UTC over Goias state in Brazil. On Jan 23 Space-Track released an estimate reported that entry at 80 km was at 1746 UTC +/- 1 min, off the coast of Chile at 46S 87W; this estimate seems likely to be reliable and is probably derived from DSP infrared. The quoted location matches the final element set's ground track at about 1746:40 UTC.
• On Jan 25 ESA announced a reentry time at 10 km of 1745 UTC, with an uncertainty of +/-7.5 min. Adopting ESA's estimated descent time of 7 minutes from 80 km to 10 km, this corresponds to an 80 km reentry at 1738 UTC +/- 7.5min, consistent with the Space-Track value within the quoted uncertainties