Odyssey will carry out a surface survey

Matthew Landano said: "We up-linked the sequence of commands that control the orbit insertion on 15 October. Now, we will closely monitor the spacecraft's progress as it approaches Mars and executes the orbit insertion burn."

To enter orbit, Odyssey's fuel tanks must be pressurized, plumbing lines heated, and the system primed before 262.8 kilograms (579.4 pounds) of propellant are ignited for 20 minutes to push the spacecraft in exactly the right direction.

The burn is scheduled for 24 October at 0426 GMT. Shortly after the start of the burn, the spacecraft will pass behind Mars and will be out of contact for about 20 minutes.

Atmosphere brushing

The spacecraft's speed should decrease, allowing it to enter a highly elliptical Martian orbit.

Over the following weeks and months, Odyssey will repeatedly brush against the top of the atmosphere in a process called aerobraking, to reduce the long, 19-hour elliptical orbit into a shorter, 2-hour circular orbit of approximately 400 km (250 miles) altitude desired for the mission's science data collection.

Odyssey carries several scientific instruments to map the chemical and mineralogical makeup of Mars.

It has a gamma-ray spectrometer that includes a neutron spectrometer and a high-energy neutron detector, a thermal-emission imaging system, and a Martian radiation environment experiment.