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FEBRUARY 1, 1998

John McNamee
Mars Surveyor 98 Project Manager

The 1998 Mars Surveyor orbiter is 312 days from launch and the lander is 335 days from launch (as of 2/1/98). The following provides a summary description of the current Project status as of February 1, 1998.

Orbiter Integration and Test

The orbiter spacecraft has been fully assembled and checked out functionally. Major tests successfully completed include the Deep Space Network (DSN) Compatibility Test, the Bus Functional Test (BFT), Mission System Test #1 (MST #1), and the modal survey. Descriptions of the Bus Functional Test and the Mission System Test are included below. The Pressure Modulator InfraRed Radiometer (PMIRR) flight instrument is integrated and all interfaces and functionality have been verified. The Mars Color Imager (MARCI) electrical interface unit (i.e., electrical equivalent camera less optics) is integrated and interfaces are verified. The flight camera is on schedule for integration in February prior to thermal vacuum testing. The refurbishment of the orbiter flight processor and power distribution and drive unit ATLO Test Units is complete and all orbiter electronics are in their final flight configuration. The orbiter is in the Reverberant Acoustics Lab (RAL) at Lockheed Martin in Denver and is being prepared for acoustic testing.

The current schedule for the orbiter is:

2/17/98 - Start Acoustic Test
2/26/98 - Start ElectroMagnetic Interference/Compatibility Tests (EMI/EMC)
4/3/98 - Start Thermal Vacuum Testing
9/3/98 - Ship to Kennedy Space Center (KSC)
12/10/98 - Launch

The schedule maintains 71 days of margin prior to shipment and 20 days of margin at KSC.

Significant mass margin for the orbiter exists with essentially all elements weighed. Recent orbit insertion analyses indicate that by utilizing just a portion of the expected margin at launch to further fill the hydrazine and ox tanks will allow the orbiter to insert directly into a 15 hour or shorter period orbit. This provides significant margin against aerobraking uncertainties and increases the probability that the orbiter will be in place to support the lander at lander arrival.

Lander Integration and Test

The lander spacecraft is fully integrated electrically and all interfaces have been verified. Major tests successfully completed include the Deep Space Network (DSN) Compatibility Test and the Bus Functional Test (BFT). In addition, the lander to orbiter UHF relay was tested successfully using both spacecraft in the high bay at LMA. Installation of the lander science payload is in process. The flight Lidar, Meteorology package, Surface Stereo Imager, Robotic Arm, and Robotic Arm Camera, have been installed on the spacecraft and functional testing is in progress. The flight Mars Descent Imager will be installed next week and the flight Thermal and Evolved Gas Analyzer experiment will be installed in June prior to landed configuration Thermal Balance testing. The lander is in the high bay facility at Lockheed Martin and will be moved to the Reverberant Acoustics Lab in March for the start of environmental testing.

The current schedule for the lander is:

3/21/98 - Start Acoustic Test
3/31/98 - Start EMI/EMC Tests
5/4/98 - Start Cruise Thermal Vacuum Test
6/23/98 - Start Landed Thermal Balance Test
10/14/98 - Ship lander to KSC
1/3/99 - Launch

The current lander schedule maintains 41 days of margin prior to shipment with 20 days of margin at KSC.

Significant mass margin for the lander exists with full tanks and most elements weighed. In all likelihood the lander will be well below the maximum design mass providing significant margin against launch vehicle performance shortfalls, entry heating limits, parachute deployment limits, and landing site elevation uncertainties.

Bus Functional Test The purpose of the Bus Functional Test (BFT) is to verify the end-to-end core command and control functionality in an integrated vehicle configuration. The major parts of the test include complete testing of uplink and downlink command and data capability (data rates, file sizes, etc.), non-volatile memory read and write functionality, and test of the Command and Data Handling Module Interface Card (C-MIC) functions which control heartbeat, fault recovery, and vehicle state. Also, end-to-end phasing of the Attitude Control Subsystem from sensor inputs through actuator commands is tested in a quasi-closed loop manner. The BFT is conducted on both A&B sides of the hardware. Some miscellaneous functions also will be verified as part of the BFT, including voltage drop verification throughout the longest harness cable run, launch event detection logic, and critical command aliveness functions to be used in later tests. The BFT represents a major milestone in the integration and test phase of development.

Mission System Test

The Mission System Tests (MST), which consist of the System Aliveness Test (SAT), the Mission Profile Test (MPT), and Sequence Verification Test (SVT), are run before and after each environmental test and after the spacecraft is shipped to KSC. The SAT is a standard, multiple use test that will be run as the first part of each MST. It's purpose is to demonstrate continuity of the electrical signal and power paths, meaning that all components are operational and able to receive commands and send telemetry. The significance of this first SAT is in demonstrating that the spacecraft has achieved a fully integrated system of software and hardware and to establish the baseline data for subsequent runs of the SAT. Unlike earlier subsystem level tests on the spacecraft, this end to end test was performed without the aid of ground support equipment and thereby establishes a higher level of verification of the hardware / software interfaces. Orbiter MST #1 also includes a limited mission profile test (MPT).

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