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Mars Surveyor 98 Update - February 1, 1998


                  1998 MARS SURVEYOR PROJECT STATUS REPORT
                              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 on the attachment.
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).

For more information on the Mars Surveyor 98 program,
please visit the Mars Surveyor 98 home page:

http://mars.jpl.nasa.gov/msp98/