content 17-July-2019 00:23:53

Mission operations

Phobos-Soil (Phobos-Grunt) was launched on 8 November 2011 on a Zenit rocket from the Baikonur Cosmodrome in Kazakhstan. At launch, the spacecraft will be inserted into a 200-km circular orbit around Earth with an inclination of 51.8 degrees. After four hours of flight (2.8 revolutions) in this orbit, the propulsion system will be switched on to transfer the spacecraft into an elliptical orbit (230 x 11100 km, period 3.65 hours) from where it is transferred onto a trajectory to Mars. The cruise to Mars will last 10-11.5 months – the time being determined by the launch window, initial velocity pulse and by any trajectory corrections that are carried out during the cruise phase.

Phobos-Soil (Phobos-Grunt) mission profile.
Credit: Lavochkin Association

The first manoeuvre during Mars approach will insert the spacecraft into an elliptical orbit around Mars at which time YH-1 (a Chinese spacecraft piggybacking on the launch) will separate from the main spacecraft. After 7-8 revolutions around Mars, the spacecraft will be transferred to an intermediate elliptical orbit. Then new manoeuvres will circularise the orbit, approximately 500 km from Phobos, in the moon's orbital plane, with a period of 8.3 h. In this orbit, the spacecraft will approach Phobos at a distance of several hundred kilometers once every four days. Accurate navigation measurements will be performed before entering QSO. The landing site has been chosen using Mars Express image data. The time of landing as well as takeoff of the Return Module will be decided based upon observations of Phobos taken by the spacecraft in QSO.

Parked in QSO, the spacecraft will stay approximately 50 - 130 km from Phobos, with an orbital period of 7.36 h. Measurements in this orbit will give an accurate position of the the spacecraft with respect to Phobos and allow the study of the landing site on the surface of Phobos.

The Mission Control Centre is located at the Lavochkin Association which has connections with satellite communication antennas at Bear Lakes, Ussuriysk and Baikonur. ESA provides ground station support for the mission under an agreement with the Russian Federal Space Agency on the ExoMars and Phobos-Soil (Phobos-Grunt) missions.

The parameters of each of the spacecraft's orbits are listed in the table below. (For definitive values please refer to the AO documentation.)

Mission phase Begins Ends Orbital parameters
Launch and cruise to Mars 8-Nov-2011 11-Sep-2012
Orbits near Mars
3-day elliptical orbit before separation of YH-1 11-Sep-2012 21-Sep-2012 Semi-axis (km) 41769.96
Eccentricity 0.90
Period (h) 72.00
Max. altitude (km) 75939.92
Min. altitude (km) 800.00
Inclination (J2000, deg) 38.94
3-day elliptical orbit after separation of YH-1 21-Sep-2012 30-Sep-2012 Semi-axis (km) 41194.57
Eccentricity 0.90
Period (h) 70.51
Max. altitude (km) 74809.74
Min. altitude (km) 779.39
Inclination (J2000, deg) 38.69
3.3-day elliptical orbit 30-Sep-2012 8-Oct-2012 Semi-axis (km) 43375.89
Eccentricity 0.77
Period (h) 76.19
Max. altitude (km) 73452.79
Min. altitude (km) 6499.00
Inclination (J2000, deg) 7.69
Observation orbit 8-Oct-2012 14-Jan-2013 Semi-axis (km) 9871.61
Eccentricity 0.00
Period (h) 8.27
Max. altitude (km) 6471.61
Min. altitude (km) 6471.61
Inclination (J2000, deg) 37.69
Quasi Synchronous Orbit 14-Jan-2013 14-Feb-2013 Semi-axis (km) 9373.29
Eccentricity 0.01
Period (h) 7.65
Max. altitude (km) 6073.73
Min. altitude (km) 5872.84
Inclination (J2000, deg) 36.84
Landing 14-Feb-2013 14-Feb-2013
Sampling 14-Feb-2013 18-Feb-2013
Phobos-Earth transfer of Return Module 18-Feb-2013 Aug-2014
Operation at the Phobos surface 14-Feb-2013 14-Feb-2014

 

 


Last Update: 08 November 2011

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