Mars Orbit Insertion
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What is Mars Orbit Insertion?
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.