Mars Orbit Insertion [ Archive page ]

What is Mars Orbit Insertion?

Image courtesy of ESA.

Mars Orbit Insertion is the point in the mission when the spacecraft arrives just short of Mars, fires an onboard rocket to slow its speed relative to the planet, and is captured into a long looping orbit.

What will happen during Mars Orbit Insertion?

On the appointed day Mars Express will be approaching Mars at a speed of 5.07 kilometers per second, or 11,341.2 miles per hour. At a distance of 523.2 kilometers (325.1 miles) from the surface of Mars, the spacecraft is readied for the engine firing that will brake its approach speed and allow Mars Express to be captured into Mars' orbit. The Mars orbit insertion "burn," as it is called, is performed by the orbiter's main engine. The 264.4 kilograms of propellant (582.9 pounds) of hydrazine fuel and nitrogen tetroxide oxidizer that will mix in the controlled combustion of the engine firing represent about 25% of the weight of the entire spacecraft. The engine provides 414 newtons, or 93 pounds of thrust.

As a result of the burn, the speed of Mars Express will change by .804 kilometers per second or 1797.7 miles per hour. The 34-minute burn will reduce the spacecraft's speed, relative to Mars, to 4.27 kilometers per second, or 9543.5 miles per hour.

NASA Participation During Mars Orbit Insertion

NASA will provide Deep Space Network tracking support and navigation assurance through workshops and technical consultation for this phase of the mission.

Preparations for the orbit insertion are intense. Precise measurements must be made to learn the spacecraft's position, its velocity and heading. Telecommunications with the spacecraft, conducted through ESA's New Norcia tracking station and NASA's Deep Space Network, depend upon the smooth and integrated operation of large antennas located at communications complexes around the world. Traveling at the speed of light, it takes a radio signal about 8 minutes and 30 seconds to traverse the distance between the spacecraft and Earth. Because of the time delay involved, along with communications outages that will occur when Mars Express passes behind Mars, the spacecraft is programmed to perform all the required actions independent of ground operators. On the Mars Express orbiter, thousands of software commands, mechanical and pyrotechnic events must be successfully executed right on time for the insertion maneuver to succeed.