Mars Return Mission

*Back to Mars Activities*

NASA, ESA, JAXA, Roscosmos and other space agencies are planning a manned mission to Mars, and Spaceflight Simulator offers us a way to test how such a mission would look. A **Mars return mission** is easier to do than a similar mission to Mercury or Venus.

A big rocket with enough fuel is enough for a Mars return mission. The biggest challenge is the fact that Mars has a tenuous atmosphere and the rocket will require many parachutes and additional retrorocket firing for landing.

## Rocket

The game has no pre-built rockets and any player is free to build its own spacecraft. The rockets described on this page can be build with the free version of the application, and correspond to the spacecraft show on the left, which requires in-orbit assembly from the launch of two different rockets : the mars rocket, and a tug intended to provide additional fuel and engine for mars tranfer.

### Mars Rover Rocket

This rocket is designed for a Mars return mission with Mars landing and deployment of two Mars rovers, before returning back to earth the capsule. Except the two between second stage and Mars main spacecraft, all the stage separators hide a Hawk engine.

From top to bottom, this rocket is composed of: parachute, capsule, heat shield, stage separator, 15t fuel tank with two docking ports and two RCS thrusters on it. Hawk engine, stage separator with two side parachutes on it, 20t fuel tank with two rovers mounted on it with side separators, U shaped structural part supporting two landing legs, Hawk engine and a stage separator linking this descent stage to main spacecraft.

The rovers are made of a probe with four wheels.

The main spacecraft is made of a 5t tank at et center with a docking port below it and the stage separator for descent stage above. On each side of this center tank there is a 5t fuel tank with an aerodynamic nose cone, and on its side, a 20t tank with aerodynamic noze cone on it with another 20t tank with Hawk engine and aerodynamic noze cone on its side.

The main spacecraft is linked to the second stage with two stage separators on both sides of its center 5t fuel tank supporting the docking port. The second stage is made of seven 20t fuel tanks with a Hawk engine on each of them.

Below the second stage there is the first stage connected to it with seven stage separators. It is made of seven 20t tanks with a Hawk engine on each of them.

### Mars Tug

This rocket is designed to put into earth orbit a tug, in order to provide additional Hawk engine and 120t of fuel to a deep space mission. It can be used for Mercury, Venus or Mars return mission, but Mars return mission only requires one of them, when Mercury and Venus requires much more. It derailed composition is given in Venus Return Mission page.

## Mission

This example of return mission to Mars, feasible on free version of the application, consists of in-orbit assembly of the spacecraft, transfer to low Mars orbit, descent and landing, rovers deployment, launch and rendezvous in Mars orbit, transfer to Earth and atmophere reentry.

### Spacecraft in-orbit assembly

This phase is performed the same way as for the Venus return mission.

### Transfer to Mars low orbit

For this phase, simply use the "Navigate To" functionality by clicking on Mars and applying the show Delta-V once "Transfer window" is reached. Once outside Earth sphere of influence, perform a trajectory correction at 0;1% thrust to make a Mars flyby at 39km. Once at 39km of Mars, burn retrograde to enter a circular orbit at this altitude. Jettison the Tug as soon as it can be empty by transfering its fuel to the main spacecraft.

### Mars landing

The landing procedure with the spacecraft given as example in this page is the following:

1. Burn retrograde at 30% when passing above Hellas Planitia in order to lower the periapsis to approximately 4000m
2. Keep engine facing the moving direction when entering Mars atmosphere, to avoid damaging the capsule's parachute
3. Burn at 100% thrust as soon as 200°C is reached, and end the burn when reaching 150°C. It should be necessary to do this twice
4. When reaching 4500m, open the two parachute **mounted of the sides** of the upper stage (NOT the one of the capsule mounted at the top)
5. Once below 1000m altitude, monitor the speed and altitude and perform short burn at 100% thrust to lower the speed when it reaches more than 1/10th of the altitude (e.g. burn when altitude is 170m and speed 25m/s). Try to keep the speed 1/10th of the altitude until touch down.

Once landed, you can deploy the two rovers by clicking of their side separators.

### Returning home

The return trip from Mars surface to earth consists of launch from Mars surface, rendezvous with the main spacecraft at 39km circular orbit, Well note that once separated from the decent stage, the main spacecraft is not controllable. Its is manageable if this spacecraft is leaved on circular Mars orbit because rendezvous can be entirely performed by controlling the ascent stage. Once docked back to main spacecraft, use "Navigate To" functionality for the transfer to the Earth and perform direct atmosphere reentry because the heat shield is able to withstand the speed when returning back from Mars.

## See also

* Mars
* Mars Activities
* What To Do In Spaceflight Simulator
* Achievements