Scientists are looking for a way to land heavier vehicles on Mars

Scientists are looking for a way to land heavier vehicles on Mars

Artistic vision of a retro-pulsed spacecraft to control

The Curiosity rover (1 metric ton) became the heaviest landing vehicle on Mars. But in the future, for colonization, you will need to send much more cargo in the range of 5-20 tons. To perform a safe landing, you need to understand how to manage large masses.

Usually the vehicle enters the Martian atmosphere at hypersonic speeds (about 30 max), quickly slows down, deploys the parachute and activates rocket engines or airbags.

Unfortunately, parachute systems are difficult to scale with increasing mass of the device. Therefore, scientists want to eliminate the parachute and use larger rocket engines to reduce.

When the landing gear slows down to 3 Max, jet engines are activated in the opposite direction to slow down the vehicle and perform a controlled landing. The trouble is that this burns a huge amount of fuel. The propellant increases the mass of the apparatus, because of which the cost of the mission is greatly increasing. But every kilogram of fuel takes this mass from scientific instruments and crew seats.

When the machine flies at hypersonic speed, a certain lift is created before launching the rocket engines, which can be used for control. If you move the center of gravity so that it is not uniform, but heavier on one side, you can direct the flight from a different angle. Researchers say that the flow around the apparatus differs from above and below, which causes imbalance and pressure drop. At the entrance, descent and landing there is an opportunity to manage transport. But, if we are going to start engines on 3 Max, then how should we aerodynamically control the device in hypersonic mode in order to use the minimum amount of fuel and maximize the payload mass?

In this matter, the height at which the descending engines are started is important, as well as the angle that the velocity vector creates with the horizon. The study examines optimal control methods for finding a safe landing strategy in hypersonic mode under various interplanetary landing conditions.

Analyzes show that for rocket fuel the entrance to the atmosphere with a lift vector directed downward will be optimal, as a result of which the device dives. Then at a certain point (based on time or speed) you need to switch to lift so that the unit moves forward at a low altitude. This allows you to transport more time in flight at low altitude, where the density of the atmospheric layer is higher. Due to this, resistance increases, reducing the amount of energy expended.

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