Mars Landing Mission

*Back to Mars Activities*

Unlike a Mars Return Mission, a **Mars landing mission** is cheaper. Depending on the purpose, there can be several types of landings on Mars:

* Hard Mars landing (as performed by the first historical probes that landed on Mars);
* Soft Mars landing (as performed by most of the rockets that sent probes and rovers to Mars).
	+ Payload delivery Missions (they bring payloads to Mars);
	+ Supply missions (if you have a space colony and want to expand it).

## Basics

Depending on what payload you intend to send to Mars, you will need a larger or a smaller launch vehicle. The Delta-v requirement for a Mars mission is not that much as to go from Mercury (and back) or Jupiter. Most of the fuel will be spent to reach low Earth orbit.

Mars has a small gravity at 3.72 m/s2, which is 3/8 that of Earth's, but a relatively large sphere of influence, larger than Mercury's, because it is further from the sun. After reaching low Earth orbit and entering the transfer window, there is room for additional trajectory correction maneuvers. In addition, the Martian atmosphere can be used to aerobrake or aerocapture.

A major disadvantage is that Mars has a thin atmosphere, which is unable to slow down a rocket completely, but can also result in little heating effects. To do so, a rocket needs to use heat shields and many parachutes, to conduct a retrorocket burn or deploying a parachute while burning retrorockets at the same time.

## Rocket

If the purpose is just to bring a capsule or a probe to the surface of Mars, then one can easily use the Spaceflight Simulator Model Rocket, which is shown on the desktop icon (top-right image). The rocket needs some improvements. The best way to do this, is to remove the top parachute, replace it with a 4×1 Structural Part and 2 1×1 struts around it and attach 3 side parachutes on it. The rocket will use its boosters and its core stage at liftoff, and when the boosters run out of fuel, they separate from the rocket, then the first stage takes over to get to low Earth orbit. The second stage is more than enough to reach Mars.

If the purpose of the mission is to bring a rover or other supplies for a Mars colony, **you have to build a modified rocket**.

### Hard landing

This is the most simple way to bring something down on Mars. Just set an impact trajectory and let the rocket crash. A rocket coming from a hyperbolic orbit will be destroyed quickly by its atmosphere. Another reason is the player fires the engines/retrorockets too late. This will result in substantial damage to the rocket.

### Soft landing

To do so, fix the trajectory until the periapsis is as close to the Martian surface. This way, the atmosphere will slow down the rocket enough to land safely.

The Martian atmosphere can be used to safely to aerobrake or aerocapture. By setting the flight path with periapsis at 8–10 kilometers high, a rocket will usually be slowed enough to enter orbit. The second time the rocket passes through the atmosphere, it may still reach space at apoapsis. If you want the probe to become an orbiter, conduct a periapsis raise maneuver. Usually, during the third pass through the atmosphere, the rocket will be slowed enough not to reach space again.

Aerobraking can be used to slow down a rocket in another manner. By setting the flight path to nearly touching the Martian surface (a periapsis at less than 6 kilometers high), the rocket will not escape back into space.

Finally, during the last moments of descent, the rocket will need to deploy its parachutes, conduct engine/retrorocket burns, or both at the same time.

### Fixed point landing

*See also:*
This is the most challenging part. Before everything, you need to have something on the surface (a landmark, a rocket or anything that help you pinpoint the landing location).

The rocket needs to enter Mars orbit. Then, when the rocket is nearing the landmark/rocket, it must turn on the engines and burn retrograde. Repeated course corrections are needed. The atmospheric drag is too small and the rocket will need to conduct multiple engine burns to land safely at the designated point.

The use of a parachute in the last part of the descent can be helpful. Also, the use of RCS thrusters can be a good idea to correct the trajectory.

## Trivia

* In-real life 18 out of the 11 missions have been successful.

## See also

* What To Do In Spaceflight Simulator
* Mars
* Mars Activities
* Mars Return Mission