# Propellants used for different Mars landers [till 2018]

What propellants have been used by lander to land on Mars surface?

• With the edit to the question, the answers could change over time as more landers arrive at Mars. Is there a reason to change the question from one about InSight to one about all Mars landers? – Don Branson Nov 30 '18 at 16:56
• @Amar I understand why you made the edit, but making a big change in a question after answers are posted is considered bad practice, and unfair to those who have already written answers. If an edit to a question may impact an existing answer, it's good to at least leave a message under the existing answers so that those users will know the question has changed. Here's an example of what that can look like. – uhoh Dec 1 '18 at 3:08

## Successful landers and rovers

Viking 1/2: monomethylhydrazine and nitrogen tetroxide for the orbiter; hydrazine monopropellant for the lander.

Pathfinder/Sojourner: three solid retrorockets.

MER/Spirit/Opportunity: hydrazine monopropellant.

Phoenix: hydrazine monopropellant.

MSL/Curiosity: hydrazine monopropellant.

InSight: hydrazine monopropellant.

## Failed landers and rovers

Mars 2/3: These identical Soviet spacecraft used pressurized nitrogen for attitude and four solid fuel retrorockets. Both included a sled called Prop-M which some describe as a "rover".

Mars 6/7: Unspecified retrorockets. Given the Soviet tendency to reuse designs, it is likely the same as Mars 2/3.

Mars Polar Lander / Deep Space 2: hydrazine monopropellant for the lander. Deep Space 2 were basically fancy lawn darts dropped from the lander.

Beagle 2: Just parachutes and airbags, no propulsion.

ExoMars Schiaparelli: hydrazine monopropellant.

Clearly hydrazine is the propellant of choice for modern landers. No wonder why it is central to the plot of the book/movie The Martian!

According to InSight Spacecraft Overview, the lander uses hydrazine:

The Propulsion Subsystem of the InSight Lander is identical to that flown on Phoenix – featuring a total of 20 thrusters broken down in three different groups: 1) Reaction Control System thrusters with a nominal thrust of 4.5 Newtons, 2) Trajectory Correction Thrusters operating at 22 Newtons and 3) Pulsed Landing Thrusters generating 293 Newtons of thrust for attitude control and velocity reduction during the Mars Landing Maneuver. All thrusters are fed from two central tanks containing ~65 Kilograms of usable propellant.

All thrusters use the decomposition of Hydrazine monopropellant over a metallic catalyst bed to create high-pressure gas that can be expelled through a nozzle to generate thrust.

• +1 This is a perfect answer to the question as it was written. Afterward, a third party changed the question to "different Mars landers" (which is not usually considered as good practice once answers have been posted). – uhoh Dec 1 '18 at 2:57