Tomorrow, Surveyor will arrive at Mars after a 10-month voyage from its Cape Canaveral launch site. Currently, the spacecraft is 300,000 km from the red planet. This distance, less than that between the Earth and Moon, is shrinking at a rate of 2,930 meters per second.

Project manager Glenn Cunningham reports that "everything is picture perfect" with respect to preparations both on the ground and on the spacecraft for tomorrow's orbit insertion burn. After yesterday's successful propellant pressurization, tank pressures are holding steady at 276 pounds per square inch, and spacecraft temperatures are normal.

The orbit insertion burn will start at 6:31 p.m. PDT Thursday evening and will last for about 22 minutes. During that time, Surveyor's main rocket engine will expend nearly 280 kilograms of propellant to slow the spacecraft's velocity by 973 meters per second. About 12 minutes after the start of the burn, Surveyor will past behind Mars and contact will be lost because the planet will block the radio signal.

When the spacecraft reemerges from behind Mars at 6:57 p.m. PDT, the burn will already be complete. At that time, the spacecraft will be captured in a highly elliptical orbit around Mars that will take 45 hours to complete. The low point of the orbit, at 250 km above the Martian surface, will be located near the position that Surveyor will pass through approximately half way through the burn. The high point of this new orbit will lie on the opposite side of the planet at an altitude of about 56,000 km.

During tomorrow's activities, please visit the Surveyor web page for updates. Many items will be updated in realtime including simulated views of the spacecraft as seen from the Earth, simulated views of Mars as seen from the spacecraft, displays of real navigation data during the burn, and a countdown clock that will display the spacecraft speed, altitude, and time to critical mark events. In addition, the web page will also contain a movie that shows the features of Mars as the planet rotates. The camera team, led by Dr. Michael Malin, constructed this movie using data obtained when Surveyor imaged Mars in late August.

In other news related to coverage of Mars orbit insertion on the World Wide Web, the Surveyor home page has moved. Please use the new address:

After a mission elapsed time of 307 days from launch, Surveyor is 253.45 million kilometers from the Earth and will intercept Mars tomorrow at 6:31 p.m. PDT. The spacecraft is currently executing the T1 command sequence, and all systems continue to be in excellent condition.

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Status report prepared by:

Office of the Flight Operations Manager
Mars Surveyor Operations Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109
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