After launching from Earth at the end of July 2020, it took Perseverance six months to get to Mars and it will take her seven minutes to enter the atmosphere and land on the surface. The performance of the spacecraft in those crucial last minutes will make or break the mission (at a cost of $2.9 billion).
NASA’s Mars 2020 Perseverance Rover will land on Mars this Thursday 18 February 2021.
Entry, descent and landing - The Countdown:
16 min: Travelling at a speed of 17,000 km/h and at an altitude of 1,600 km, the Cruise stage will separate from the rover, which will be spinning for an extra minute.
15 min: Two 70kg balancing masses will be ejected and spinning will be under control.
10 min: Travelling at 18,000 km/h, the rover will be at 500 km from the surface but still 1,600 km from the landing site.
7 min (8:48pm on 18 Feb 2021): Travelling at 19,000 km/h at an altitude of 132 km and 640 km from the landing side, the spacecraft will reach the Entry Interface Point, penetrating the Martian atmosphere.
6 min: At an altitude of 52km, 322 km from the landing site, the spacecraft will fire compensatory thrusts to adjust its direction as it encounters uneven concentrations of gasses during the Guidance phase. Friction against an increasing concentration of gas particles in the atmosphere will drastically slow dawn the fall and generate immense amounts of heat. The rover will be protected by its Heat Shield, which will glow orange from the heat.
5 min: At an altitude of 17 km, 123 km from the landing site, the speed will be 7,400 km/h. The spacecraft will continue to adjust its direction before entering the Heading Alignment phase.
4 min: At an altitude of 16 km, 50 km from the landing site, the speed will be 2,500 km/h and the Heat Shield will start to cool down. Jezero crater, the spacecraft’s target, will be in sight.
3 min: At an altitude of 13 km and 21 km from the landing site, the speed will be 1,700 km/h as the spacecraft begins the Straight Up and Fly Right (SURF) manoeuvre. Six balance masses will be ejected, and thrusters will adjust the angle of attack to zero.
2:45 min: At an altitude of 11 km and 14 km from the landing site, with a speed of 1,500 km/h, the spacecraft will calculate the correct distance to its target and deploy its Parachute in an operation known as Range Trigger.
2:26 min: At an altitude of 9 km and 10 km from its destination, the speed will be 600 km/h. While the spacecraft is still suspended from its parachute, the Heat Shield will separate from the bottom, exposing the rover and the Rover Cameras to the Martian terrain.
1:25 min: At an altitude of 4 km and still 4 km away from the landing site, the speed will be 300 km/h and the acquisition of Terrain Relative Navigation (TRN) images will begin. Those pictures will help the onboard computer correct the trajectory of the spacecraft in seconds to guide it towards a safe landing zone.
1 min: At an altitude of 2 km and 2 km from the now decided target, the speed will be just below 300 km/h when the Descent Stage will separate from its Back Shell and Parachute and begin rocket-powered propulsion to control its vertical and horizontal speeds.
30 sec: At an altitude of 300 m and 300 m from the landing site, the speed will be 120 km/h as the rover keeps approaching the surface in controlled flight.
18 sec: At an altitude of 22 m over the landing site, the speed will be controlled at 11 km/h as the Descent Stage starts throttling down to hover over the surface.
16 sec: At an altitude of 21 m the velocity will be at its lowest (2.7 km/h) as the Descend Stage begins Rover Separation.
13 sec: At 13 m of altitude the speed will be 9 km/h as the Rover is lowered on a set of cables in a crane-like operation. As this happens, the Rover will deploy its wheels.
10 sec: At an altitude of 8 m, the velocity will be 4 km/h and the Rover will prepare to contact the surface.
0 sec (8.55pm on 18 Feb 2021): Touch down on Mars. When the Rover senses that the wheels have touched the ground, it will cut the cables and the Descent Stage will fly away until it expends all its remaining fuel and crashes into the terrain.
+ 10 seconds after landing: Surface Operations will begin.
The Perseverance Rover is an astrobiological mission, searching for signs of life in Mars. Find more about the rover and the mission in our previous post “Persevere to Succeed ”.
Entry, Descent and Landing of Perseverance Rover on Mars on 18 February 2021. NASA/JPL, 2020.
Perseverance will not be alone
The China National Space Administration (CNSA) launched the “Tianwen-1 (TW-1)” mission on 23 July 2020 and entered Mars’ orbit on 10 February 2021.
During one Martian year (two Earth years), the orbiter of this mission will study the atmosphere (climate, seasons, environment) and the upper region which is ionised by solar radiation (ionosphere), it will also study the composition of rocks, mineral content and weathering minerals looking for characteristics of water and ice distribution and evidence of life. It will also study electromagnetic and gravitational fields, and the internal structure of Mars. There are 13 scientific projects onboard the orbiter.
The orbiter’s instruments include: The Mars-Orbiting Subsurface Exploration Radar, Mars Mineralogy Spectrometer, Mars Magnetometer, Mars Ion and Neutral Particle Analyzer, and Mars Energetic Particle Analyzer.
The orbiter carries a 250-kg Rover that will land on the Utopia Planitia in April or May 2021; the rover’s mission will last 90 Martian days (sols), during which it will collect samples to be retrieved by future missions.
The rover carries: The Multispectral Camera, Terrain Camera, Mars-Rover Subsurface Exploration Radar, Mars Surface Composition Detector, Mars Magnetic Field Detector, and Mars Meteorology Monitor.
This is a Space Race
The United Arab Emirates Space Agency (UAESA) launched the “Mars Hope” mission on 19 July 2020 and arrived at Mars on 09 February 2021 entering orbit successfully. The following day it took the first picture of Mars at an altitude of 24,700 km from the surface (The image on the right shows a model of Mars Hope over the picture of Mars taken by the orbiter on Wednesday 10 February 2021).
This mission will orbit the planet to create a holistic diurnal picture of Mars’ atmosphere.
REFERENCES
(Links open in a new tab or window depending on your browser's settings.)
» NASA (2020) Entry, descent and landing. [Online page]. Available here. (Accessed: 16 Feb 2021).
» NASA (2021) 7 Minutes to Mars: NASA's Perseverance Rover Attempts Most Dangerous Landing Yet. [Online video]. Available here. (Accessed: 17 Feb 2021).
» Wan, W.X., Wang, C., Li, C.L. et al. (2020) China’s first mission to Mars. Nat Astron 4, 721. DOI: 10.1038/s41550-020-1148-6. [Journal article]. Available here. (Accessed: 16 Feb 2021).
» Wall M (2020) China launches ambitious Tianwen-1 Mars rover mission. [Online article]. Available here. (Accessed: 16 Feb 2021).
» Arab News (2021) UAE’s ‘Hope’ probe sends home first image of Mars. 14 February 2021. [Online article]. Available here. (Accessed: 16 Feb 2021).
» Guessoum N (2021) How the UAE’s Mars mission can be the Arab world’s springboard to the future. Arab News, 14 February 2021. [Online article]. Available here. (Accessed: 16 Feb 2021).
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