The Mars Orbital Insertion (MOI) manoeuvre involves reversing the spacecraft and firing the Hope probe’s six Delta-V thrusters in a 27-minute deceleration ‘burn’ to rapidly slow the speed of the spacecraft from 121,000km/hr to 18,000km/hr, and will see the Operations Team confirming whether the Probe has achieved a stable capture orbit around Mars.
Omran Sharaf, Project Director of the Emirates Mars Mission, said: “We are nearing the most critical part of the mission. Though we have carried out multiple tests and are confident about the manoeuvres we have performed, space exploration always includes an element of risk and we are keenly aware that 50 per cent of all missions to Mars have failed. Despite years of tests and peer reviews, this operation is the first time our platform has been tested in such a complex and stressful manoeuvre in deep space.”
MOI is set to commence just after 7.30pm UAE time on February 9, with the signal confirming the manoeuvre to reach Earth 11 minutes afterwards. The delay is caused by the radio signal having to travel the long distance from Mars to Earth.
Attaining correct speed
Hope’s six thrusters will deliver some 650 Newtons of thrust during the burn. Should a thruster pair fail, the burn duration will increase to compensate. A second pair failing would terminate the mission. In addition to the six Delta-V thrusters, the probe also uses a set of eight RCS (Reaction Control System) thrusters, which will maintain the spacecraft’s orientation during the burn. Small adjustments to the spacecraft’s inclination are made using its four reaction wheels.
The MOI burn will commence when the spacecraft is 2,363km from the planetary surface and will see Hope reaching a proximity of 1,062km from Mars (the periapse of its planned capture orbit) before the burn ends at 1,441km distance from the planet.
Dark side of Mars
Some five minutes following the MOI burn, the Hope probe flies into the dark side of Mars, ‘occultation’. Radio signals will be lost for some 15 minutes until the probe can be contacted again. With its command and control centre based at MBRSC in Dubai, EMM depends on the Deep Space Network (DSN) of antennas for its communication. Antennas based in Goldstone, California, Canberra and Madrid. During the MOI operation, Hope’s signals will be routed through the Madrid antenna.
Hope’s capture orbit takes the spacecraft from a distance of 1,000 (periapse) to 49,380 (apoapse) km from Mars’ planetary surface. In this phase, Hope’s instrumentation will be tested and the spacecraft will, over the coming two months, transition to its science orbit.
Three Transition To Science (TTS) manoeuvres are currently planned to move the probe from its capture to its science orbit. The final number of such manoeuvres will be defined by the accuracy/success of MOI. The transition to Hope’s science orbit will be completed by April 2021.
Original news source Credit: gulfnews.com