Due to the dynamic nature of space flight operations, please keep in mind that dates of events can change a moment's notice. This calendar was last updated on 12 September 1997.

Short-Term Event Schedule
All times are listed in PDT

This time marked the conclusion of the 22-minute burn that allowed Mars to capture Surveyor into a highly elliptical orbit taking 44 hours, 59 minutes, and 34 seconds to complete. The initial orbit had a low point of 262 km above the northern hemisphere, and a high point of 54,026 km above the southern hemisphere.

Command sequence T2 will activate. This sequence will control Surveyor for one orbit to configure the spacecraft and science instruments for orbital and aerobraking operations.

The onboard computer will command the Magnetometer, Mars Orbiter Camera, and Thermal Emission Spectrometer science instruments to activate. Both the magnetometer and spectrometer will start to collect data on a continuous basis. The camera must wait for opportunities to be pointed directly at the planet.

Surveyor's onboard navigation system will switch from an Earth- based reference frame to a Mars-based frame.

The Magnetometer science instrument will perform a 20-minute calibration activity.

Software parameters needed to operate the spacecraft during aerobraking operations will be loaded into the flight computer.

The Mars Orbiter Laser Altimeter science instrument will be activated and configured to take altitude measurements from the Martian surface. However, data collection will not be possible unless the spacecraft turns to point the laser directly at the planet.

During a 15-minute window, the spacecraft will turn to point Surveyor's science instruments directly at the surface of Mars. This activity will permit the camera and laser altimeter to collect data for the first time during the mission. The magnetometer and spectrometer will also continue to collect data.

At this time, half-way through orbit #3, Surveyor will fire its main rocket engine to achieve a velocity reduction of 3.9 meters per second. This maneuver will cause the altitude of the next low point to drop from 262 km into the upper fringes of the Martian atmosphere at 150 km.

Surveyor's passage through the starting point of orbit #4 will mark the official commencement of the aerobraking phase of the mission. Aerobraking involves using air resistance from the Martian atmosphere to slow the spacecraft and gradually lower the high point of the orbit.

The altitude of the spacecraft at this first aerobraking pass will be 150 km. However, Surveyor's atmospheric scientists expect to see little to no atmosphere at this altitude. Over the next four revolutions around the planet, the flight team will use the spacecraft's thruster rockets to slowly lower the low point of Surveyor's orbit down to 112 km.

During these four aerobraking months, Surveyor will repeatedly fly through the Martian atmosphere during the low point of every orbit. Each one of these atmospheric passages will slow the spacecraft by a small amount and cause the altitude of the orbit's high point to decrease. Over the course of over 400 revolutions around the planet, the altitude of the orbit's high point will shrink from 54,000 km down to less than 2,000 km.

High-Level Master Schedule

Event	Date	Comments
Launch	7-Nov-96	Lift-off occurred at 12:00:50 EST
TCM1	21-Nov-96	Optimized maneuver to correct for launch injection errors (1st of 2 burn sequence)
TCM2	20-Mar-97	Flight path correction (2nd of 2 burn sequence)
TCM3	21-Apr-97	Maneuver to correct for execution errors from TCM2
TCM4	25-Aug-97	Maneuver for final adjustment for orbit insertion aim point
MOI	12-Sep-97	Mars orbit insertion burn will last for about 20 minutes, closest approach will occur at about 1:26 a.m. UTC
Orbit Insertion Phase	12-Sep-97 to 14-Mar-98	Lasts for 5 months to reach mapping orbit using aerobraking and propulsive maneuvers
Mapping Phase	15-Mar-98 to 31-Jan-00	Mapping operations will last 1 Mars year, about 687 Earth days in duration
Relay Phase	1-Feb-00 to 1-Jan-03	Communications support for future Mars missions