The Hope orbiter is a UAE Space Agency unmanned space exploration mission to Mars, which was launched in July 2020 from Japan. The probe has travelled around seven months on its journey of 493 million kilometres, which it will complete today. At that point, it will reach the crucial ‘Mars Orbit Insertion’ (MOI) stage — which means the probe will have to slow down to enable it to be captured by Mars’ gravity, to orbit the red planet. That would make the UAE the fifth country to reach the Martian orbit, after successful missions by the US, Russia, the EU, and India.
The Mars Orbit Insertion stage is called half an hour of terror! As Hope reaches close to the Martian orbit, a special manoeuvre will be performed to decrease its speed, enough for the planet’s gravity to capture the spacecraft into orbit. For orbit insertion, six Delta V thrusters will autonomously perform an action to fire the thrusters for 27 minutes to slow down the speed of the probe from more than 100,000 kilometres per hour down to 18,000kmph.
One of the difficulties is that the scientists will have no control — as because of the distance between Earth and Mars, any command sent to the spacecraft takes 11 minutes each way. Hence, all steps are pre-programmed. Also, contact will be temporarily lost as Hope travels behind Mars, creating a blackout period with no communication for a short time.
More than 50 per cent of Mars missions fail. Failure to perform the manoeuvre as planned could prevent the spacecraft from entering orbit. MOI will commence at 7.30pm (UAE time) tonight, but the signal confirming the start of the manoeuvre will reach Earth only 11 minutes later. Half the fuel will be burnt during this manoeuvre.
Nasa’s Deep Space Network radio antenna in Madrid, Spain, will be the first to know if orbit insertion was successful. After successful insertion, the mission will spend some time in the capture orbit as a transition to science phase.
During this phase, Hope’s instruments will be tested for two months before it transitions to its science orbit, using three further manoeuvres, which will be completed by April 2021.
Hope will use its three science instruments — a camera, infrared spectrometer and ultraviolet spectrometer — to provide a comprehensive view of the Martian atmosphere. Hope’s special Science Orbit enables it to conduct a series of scientific investigations, including tracking the planet’s weather that will advance our understanding of atmospheric variability on daily and seasonal timescales, and the processes by which gasses escape the atmosphere into space. It will also attempt to find out possible reasons behind its drastic climate changes, from the time it could sustain liquid water to today, when the atmosphere is so thin that water can exist only as ice or vapour.
What distinguishes Hope probe from past orbiters, is its unique scientific orbit. Most Mars orbiter missions in the past have orbits that are pole to pole, but Hope’s science orbit will be a nearly equatorial orbit, and it will allow the spacecraft to capture a complete view of the planet’s atmosphere, at all times of day in just 10 days.
The orbiter will study the Martian atmosphere over 685 Earth days. The data from the mission will be made freely available shortly after the spacecraft enters its final science orbit.
Source: The Khaleej Times