SUNNYVALE, Calif. -- When the first dedicated mission to the moon in a quarter-century gets under way late this week, it will mark the space program's first foray into a region as unfamiliar to NASA as the moon's dark side: the commercial electronics industry. Under the banner of "faster, better, cheaper," NASA and prime contractor Lockheed-Martin Missiles & Space brought the Lunar Prospector spacecraft from start of build to completion of test in a record 22 months, at a budget unthinkable back when Apollo 17 bid its final farewell to the moon.

The feat was accomplished by employing concurrent design and by leaning heavily on the existing infrastructure that serves the electronics industry. Twenty-six companies and organizations in Silicon Valley, ranging from the elegantly specialized NASA Ames Research Center to Kelley Moore Paints, supplied designs, equipment or materials to the program. Virtually nothing--not even the spacecraft chassis itself--was designed from scratch.

"It used to be that every craft had to be custom-designed," said Lockheed-Martin spokesman Buddy Nelson. "But over the years, Lockheed-Martin has built up an inventory of designs that are space-proven. Increasingly, we are able to deliver an off-the-shelf solution that meets the customer's needs.

"Prospector, for example, is built on the LM-100 bus. The LM-100 is a general-purpose platform for small scientific craft. Into that we can add the control, communications and experimental modules necessary for the particular mission."

In Prospector's case, the mission is to prospect the lunar surface virtually. The craft will enter a polar orbit, circling the moon once every 118 minutes at an altitude of 63 miles above the surface. The orbit is fixed in orientation relative to the earth, so the moon will revolve underneath the orbit once every lunar month, giving the spacecraft a complete tour of the lunar surface.

The mapping mission is scheduled to last one year. At that time, if enough propellant remains in the craft's orbit-correcting thrusters, the craft will be moved into a lower orbit, for close-up examination of interesting spots on the surface. When the propellant is gone, the craft's orbit will decay, and Prospector will become a permanent resident of the moon.

The actual surveying will be done by five instruments, deployed on extended arms beyond the spacecraft's 4.25-foot-high, 4.5-foot-diameter cylindrical body.

A gamma-ray spectrometer will detect concentrations of chemical elements in the lunar surface. A neutron spectrometer will measure concentrations of water, believed to be trapped in the lunar soil in some locations, perhaps at the poles.

An alpha-particle spectrometer will measure releases of gas from the surface, mapping volcanic activity. A magnetometer and electron reflectometer will map the lunar magnetic field, and a Doppler gravity experiment will map the gravitational force of the moon, permitting calculations of its surface density and internal structure.

In a unique cost-saving move, the experiments, communications, thermal-control and flight-control systems are not under the supervision of an on-board computer. The craft has local state machines to perform certain operations autonomously, such as recording data during the back-side portion of an orbit for retransmission once Earth appears over the lunar horizon.

But in general, Prospector is designed merely to respond to commands transmitted from the Mission Command Center in Mountain View, Calif. "There is no computer as such on board," Nelson said.

The design considerably simplified the spacecraft electronics. But it meant that the simulation and test system, which would be used to integrate, test and final-check the craft throughout its time on earth, needed to be relatively sophisticated. For that design, Lockheed-Martin turned to Hewlett-Packard Co.'s test group (Palo Alto, Calif.).

"We worked very much with the spirit of the program," reported Ted Marcopulos, solution architect at HP. "If we had done this project 10 years ago, there would have been a massive effort to build custom equipment. But today, there is so much available off-the-shelf for the VXI bus that we were able to put together just about everything we needed by plugging in components."

The HP team worked with the NASA mission designers and Lockheed-Martin spacecraft team from the beginning of the project, developing test strategies and tactics as the craft was being designed. "We even found that sometimes we would uncover inconsistencies in the design before the spacecraft team picked them up, because we were right there working on how to connect to what," Marcopulos said.

The test system for Prospector ended up being two 19-inch bays of equipment: programmable power supplies and electronic loads, and lots of data-acquisition and switching cards.

In operation, the equipment is used in conjunction with NASA's telemetry-simulation system. Simulated telemetry data is sent through the HP test fixture to the spacecraft's RF link. The HP gear is also connected via RS-422 through the craft's umbilical. A time-stamping scheme allows the HP and telemetry equipment to correlate their operations, so that the HP gear can monitor the spacecraft's reaction to a telemetry command, for instance. The HP equipment can also be used directly to actuate valves and relays or to fire the thrusters.

System checkout
"It was kind of interesting watching them test the thrusters," Marcopulos related. "In the integration process, they filled the thruster tanks with inert gas and then tied rubber gloves over the nozzles. When we activated the thrusters, they inflated the rubber gloves."

The HP equipment was used for a complete system checkout during the integration of the spacecraft. At that point, programmable power supplies were used to simulate analog signals, such as the signal from the craft's sun and earth sensors, vital to locking the craft's antennae onto earth tracking stations.

Another complete phase of testing was performed when the craft was mounted on the Athena II vehicle. Finally, today, the same equipment will be used for last-minute monitoring and for topping up the craft's batteries for their long, dark transit to lunar orbit.

If all goes well, on Jan. 10 a unique collaboration of NASA mission specialists, Lockheed-Martin spacecraft experts and commercial electronics and materials companies will slip into its orbit. The craft will orient itself for best use of its solar panels, and for accurate aim of its high-gain antenna. It will extend the long arms that carry its experiments.

And it will begin to announce, for anyone who cares to listen, that there is a profound role for the commercial electronics industry in space.

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