NASA tries the commercial approach-witness

this maxim u m-qual ity-for-m i ni m u m-cost

ground-support system for the Lunar Prospector Ted Marcopulos, Hewlett Packard Co.

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or once, a catchy slogan has proved true: NASA’s vision of “faster, better, cheaper” planetary missions is, by all accounts, a resounding success. The space agency’s

new wav of doine business is having its debut in its U ”

Discovery Series of missions, which now includes the Near Earth Asteroid Rendezvous, launched 17 February 1996 and headed for its close encounter in February 1999; the 4 July 1997 landing of the Mars Pathfinder and its plucky rover Sojourner; and the Lunar Prospec- tor, which represents the earth‘s return to the moon after a quarter-century absence.

Essentially, NASA’s new management practice is “hands off: contract for certain results and demand that

contractors use management techniques honed in the trench warfare of civilian commerce.

The next Discovery mission, to be operated by the Jet Propulsion Laboratory of the California Institute of Technology, Pasadena, is named Stardust. Scheduled for launch in early 1999, it is to gather dust grains between stars and collect samples of material surrounding a comet.

The new formula for space exploration works because it affects every level of Discovery Series operations-from mis- sion planners to ground-system subcontractors. As a result, any number of systems or design efforts could be used to illustrate how the formula has been applied. Perhaps most useful might be a look at a large project handled by subcon- tractor Hewlett-Packard Co., Palo Alto, Calif., for prime

69

Neutron spectrometer (NS) Alpha particle spectrometer (APS) \ I

Thrusters

GRS-

Thrusters

reflectometer Mast spectrometer

- MAG/ER

I Spectrometer electronics

12 J The Lunar Prospector [shown here before deplqvment in amt‘s VEWS] cams five SCEnhfiC znstruments on three “mts” a gamma ray spectrometer (GRS), to znvesh- gate the lunar cwt, a magnetometer and an electron rejlectometer (MAGIER), to map the moon‘s gravzcy field and surface gruuiy, an alpha pamk spectrometer (AI’S), to detect outgasingfrom the lunar surface, and a neutron spectrometer (NS), to detect the presence of hydrogen a m , and there- fore ofzce. Each mt IS 2.4 meters h g

contractor Lockheed Martin Missiles & Space, Sunnyvale, Calif. The project, called the Lunar Prospector Electrical Test-Set (LPETS) , is the critical ground-support system for the complete electncal sys- tem of the Lunar Prospector satellite [Fig. 11.

Launched on 6 January 1998 to a polar orbit some

(295-kg) satellite with five science instruments [Fig. 21. Its most dramatic task was to determine if the moon had polar ice caps (the answer is yes), other assignments included the detection of lunar gas release and the mapping of the moon’s surface and its gravity field. Early next year, Prospector will drop down to a 6-km close-up orbit for six months, and when it runs out of fuel, wll fall to its crashing end.

To appreciate NASA’s change in mindset, a look at the milieu from which the agency has come may be useful. Forty years ago, in the early days of the space program, the center of mass for high-technology development was in defense. It was natural for large projects, such as the Mercury, Gemini, and Apollo

100 km above the moon, Lunar Prospector is a small

manned space flight programs, to be run as if they were military developments, especially since the immediate practical uses for space technology were nearly all military. For projects of this magnitude, the military-defense methodology was clearly appropnate, as their successful legacy illustrates.

On the other hand, commercial companies, when not riding out open government contracts, pursue goals based on market forces rather than military objectives. The methods they have developed for doing business differ greatly from the defense iiidus- try’s way Companies must deal with the often con- flicting market demands of supplying top-quality prod- ucts with extremely high reliability at minimum cost Those that fail on either of these counts quickly find their sales and profits plummeting.

Today NASA, opeiatlng under Federal budget belt- tightening, faces essentially the same constraints: pro- jects have to be pared down to minimum cost, but quality (in terms of meeting scientific objectives) and reliability (in terms of having systems work flawlessly)

7 0 IEEE SPECTRUM AUGUST 1998

\ Thrusters

M

cannot be sacrificed along the way. The realization, too, that the practical applications for space technology have become overwhelmingly commercial, led NASA planners to look to commercially developed methods.

The Lunar Prospector mission was the brainchild of Alan Binder of Lockheed Martin Missiles & Space (now with the Lunar Research Institute, Mountain View, Calif.), who continues to lead the effort as Lunar Prospector principal investigator. The mission is a joint effort of NASA’s Ames Research Center, Mountain View, Calif., and Lockheed Martin Missiles & Space. Among the other participants are the Los Alamos National Laboratory in New Mexico, Berkeley’s Space Science Laboratory at the University of California, the Goddard Spaceflight Center in Greenbelt, Md., and the Jet Propulsion Laboratory.

The electrical support for the project, used in the spacecraft’s development, testing, and launching, was handled by Hewlett-Packard. The electrical system developed provides power to, and communications with, the spacecraft during all ground phases of the

[31 Uewlett-Packurd‘s Lunar Prospector elec- trical test-set (LPETS) [foreground] was built almost entirely ojcom- mercial off-the-shelf hardware and sojtware. It was used during the spacecraft‘s cmstmc- tim and assembly us well us its checkout and launch.

mission. It also supplies all the source and measure- ment capabilities needed for testing the electronic sys- tems, and it supports development and test operations for other systems as well [Fig. 31.

Some novel concepts The change in philosophy that characterizes the

Discovery Program missions begins with setting mis- sion goals. Rather than attempting large, all-encom- passing projects, Discovery missions begin with lim- ited, clearly defined scientific goals. Also different are the rules by which spacecraft development pro- jects are run. The most striking, and effective, changes were delegating responsibility, putting the financing up front, applying concurrent engineering, using commercial, off-the-shelf equipment, imple- menting minimal redundancy, and employing space- proven hardware.

It takes only a few words on each of these concepts- novel to the old NASA-to appreciate their effect. To begin with, as principal investigator, Binder was given the flexibility to implement the best available approach, rather than being handed detailed specifications. NASA, through the Ames Research Center, paid close attention to the project’s progress, but made Binder responsible for results, allowing him to use his own tech- nical insight to ensure abundant scientific returns.

In the past, money to pay for a spacecraft-develop ment project was parceled out on a milestone basis. As each milestone was passed, suppliers were subject- ed to numerous reviews and audits. That method inherently costs more because every time a supplier has to prepare for a review or an audit, it is spending money unproductively

The new model, with NASA providing full funding up front, is like the commercial one. There are still milestones, but they encompass progress meetings instead of extensive internal audits, allowing the prime contractor to use the best business-manage- ment practices for putting together the spacecraft as quickly and economically as possible.

MARCOPULOS - FASTER, BETTER, CHEAPER SPACE EXPLORATION 71

[4] The Lunar Prospector real-time electncal test-set (LPETS) w the main interface between the telemetry and command system and the spacecraft, as shown by this testing scheme

Source Hewlett Packard CO

When funding flows only as certain milestones are passed, contractors delay making commitments, wait- ing until the last minute to begin tasks. Conversely, with up-front money, suppliers can start earlier on each part of the project because they know funds will be available to complete the job. The Lunar Prospector electrical test-set, for instance, was developed concur- rently with the spacecraft, helping keep the overall schedule on track.

When the center of mass for technology develop- ment was in the military arena, a lot of equipment would only evolve into commercial products after it had been invented for a government purpose. Clearly, the private sector is now developing a lot of space technology on its own-and it is typically immediately available as a commercial off-the-shelf (COTS) product.

ble into the mission has definite advantages as far as cost, reliability, and supportability are concerned. In a commercial product, the engineering work has already been done and testing simply validates the quality of each unit as i t comes off the production line. Nonrecurring engineering costs are amortized over large numbers of units. Because the end goal is a com- mercial product, and the company is in business to make a lot of products, engineers generally spend extra effort on ensuring that the design is for some- thing that is producible, supportable, and manufac- turable to the highest standards.

Tradioonally the way to budd spacecraft for high reli- ability has been to design in redundant systems. For

Incorporating as much COTS equipment as possi-

Discovery Program missions, redundancy is minlmned or eliminated For example, the Lunar Prospector has only one transponder, whereas a traditional spacecraft would have two or even four. Reliability IS obtained by ensunng the accuracy of the primary system

Eliminating redundancy reduces the cost, weight, and time required to build the spacecraft. It also removes the complex interconnection schemes need- ed between the redundant systems, and reduces the program development work associated with making those systems work together.

The down side is that, obviously, designers may be putung all of ther eggs in one basket. Removlng redun- dancy puts a greater burden on the testmg component of the spacecraft development program So systems llke LPETS are elevated from being just another line of defense, to being a pnmary lme of defense.

Program missions have that was simply unavailable to the early space pioneers is the wealth of space-proven equipment now available. Many transponders and sci- entific modules being used for the Lunar Prospector have been flown many times before. The bugs have been wrung out and mission engineers know that the units work.

Electrical test-set

As €or hardware, one advantage that Discovery

In all aspects of the Lunar Prospector electrical test-set project, the principles behind the Discovery Program were very clearly at work Unlike most pieces of support equipment for previous NASA missions, LPETS had to be a kind of one-man band, maintains

7 2 lEEE SPECTRUM A U G U S T 1998

[5] The electrical test-set generates all the electrical needs of the spacecraft while it remained on earth. Its modules can be activated to provide low-leuel control signals, detect the status of switches, and simulate otherwise unavailable sensor outputs during ground-testing.

ing and testing components of the spacecraft’s electri- cal system from construction to checkout [Fig 41. Although using the same test-set through these phas- es saved duplicating resources, it required that the LPETS development team devise a flexible, modular product [Fig. 51.

In its first role, LPETS was an electrical test-set dur- ing the orbiter’s manufacture and integration. It sup. plied ground power, charged the battery, sent signals to stimulate devices on the spacecraft, and controlled and validated relays and actuators. It also monitored the temperature and pressure at various locations in the spacecraft, and supplied power to the spacecraft bus to cover those periods when the spacecraft systems need- ed to be run, as the craft’s solar panels obviously were unable to fumish the power.

During the checkout phase, inert gas was pumped through the rockets and valves in the spacecraft’s propulsion system to ensure they were working proper- ly. For example, technicians put an inert gas into the

tanks and used the test-set to monitor the rocket actu- ators while exercising them. To provide a visual check, they put a high-tech device-a rubber glove- over each nozzle and instructed the console operator to open the valve for short pulses. The operator typed in the command, which went through the transponder into the spacecraft. The valve opened, the glove filled with gas, and then the valve shut.

LPETS also includes a simulator of the solar array, with which engineers checked that the spacecraft would get enough power from the solar arrays under all foreseeable conditions. For example, the spacecraft is spin-stabilized around its major axis, and as it rotates, the three instrumentation booms that stick out from it shade portions of the solar arrays from the sun, so that the panels provide less power. Engineers used the solar array simulator to mimic the expected output pattern from the solar arrays to guarantee that all the internal systems will receive enough power to stay charged, and that transients generated as the

MARCOPULOS - FASTER, BETTER, CHEAPER SPACE EXPLORATION 73

shadows traverse the arrays will not degrade the oper- ation of the electrical bus.

During the next engineering phase, when the com- pleted spacecraft was integrated with the launch vehi- cle, engineers used LPETS to ensure that the space- craft was still working, and to keep batteries charged, supply ground power when needed, and communicate with the spacecraft while it was being integrated with the launch vehicle. The test-set in addition monitored temperatures and pressures in the tanks during the fueling of the spacecraft's propulsion system.

In the last phase, when the spacecraft was on the launch pad, LPETS was again needed to monitor criti- cal sensors and provide last-minute battery charging in case the launch was delayed.

From shelf to one-off ewlett-Packard treated the LPETS develop- ment as a commercial project and used as much commercial off-the-shelf (COTS) equipment as it could to put the system

together as quickly as possible. Using COTS equipment enabled the HI' team to produce a relanvely inexpen- sive system fairly quickly because the tremendous non- recurring ensneering cost of developing custom equip- ment could be avoided It also led to high-quality equipment. instead of being a one-off, its components were standard commercial products made in quantity mth standard quality assurance measures in place.

Still, not every project is lucky enough to have each of the necessary components commercially available. The elements unique to this system were the wiring harness and interface panel.

All the equipment that makes up LPETS fits into two racks. The first carries most of the system, mclud- ing the measurement, control, and sensor simulation equipment. The second rack, which can be removed from the system when not needed, carries the solar array simulators.

Most of the functionality for the first rack is embod- ied in off-the-shelf VXIbus modules installed in a C-size VXIbus mainframe. Modules in the VXI crate include a VXI command module, a 64-channel scanning analog- to-distal converter, two arbitrary waveform generators, two 32-channel C-form smtches, a 4-by16 switching m a m , and a nmecode generator.

These modules make all the measurements, gener- ate all the low-level actuation and control signals, and simulate sensor outputs (such as those from the atti- tude sensors) that otherwise would be unavailable dur- ing ground testing. Some fairly critical elements are included, such as the a-d converter that measures tem- peratures, voltages, and pressures. It also detects swtch positlons and actuator onloff conditions.

The signal sources for simulating the sun and earthlmoon sensors are also installed in the VXI crate, as are the on-off swtches. In fact, all crucial measure- ment and response capabilities are built into the VXI mainframe. Equipment external to the VXI subsystem comprises power supplies and electronic loads whose power-handling requirements makes them unfit for a VXI enmronment.

Software development In developing a test system like LPETS, the most

time goes into ensuring that the software and hard- ware work together. When the software reports that a valve has opened, it must be determined that the valve did open. The software development challenge

was that the LPETS is a real-time system. Once every second, it checks all the temperatures, voltages, switch conditions, and so on. Then, it saves the results to a file. It also must acknowledge and act upon user inputs from the control console, and save reports of that activity as well. And, of course, every- thing has to be time-stamped.

HP used commercially available software as well as hardware. One example is the software used to com- municate between the LPETS console and the remote terminal. In almost every situation, technicians con- trolled LPETS from a remote location At Lockheed's Sunnyvale site, the spacecraft and the LPETS system sat on the integration floor, while the operators were in an elevated control room some 12 meters away. A remote terminal was also needed during the integra- tion of the spacecraft with the launch vehicle because there were hazardous materials around the spacecraft.

When used to monitor the spacecraft on the launch pad, LPETS sat in a small instrumentation bunker underneath the launch pad communicating with the spacecraft through the umbilical line. The control room was more than a kilometer away at the other end of an optical-fiber link.

As recently as a couple of years ago, HP would have assigned a software engineer to write the required soft- ware from scratch. In this case, however, the team found a commercial software product, PCAnywhere, from Symantec Corp., Menlo Park, Calif,, which can map a representation of a Microsoft Windows desktop onto a remote terminal. With this commercial product, there was no need to develop any further software for the remote interface.

For the LPETS application, software was developed using HP's commercially available object-oriented pro- gramming environment HP-VEE. Once again, the commercial software development system allowed the team to complete the project quickly because graphical object-oriented programming is highly efficient. The HP-VEE language supplied a powerful high-level envi- ronment that accelerated the development of operator interfaces, simplified instrumentation control, and streamlined measurement processing.

HP-VEE operates at a very high level of abstrac- tion a single graphic object can represent hundreds of lines of code in traditional languages. Consequently, the software developers could concentrate on the big picture and not on low-level implementation details The feature enabled the LPETS software develop- ment team to have usable application software ready for integration testing in weeks instead of months. + To probe further NASA's World Wi

Discovery Series missions may be found a t http.// discovery.larc.nasa gov/discovery/home html The agen- cy's Web page for the Lunar Prospector, with links to detai ls on the science packages, is a t h t t p // lunar.arc.nasa gov/ index html.

Details on Hewlett-Pachard Co.'s HP-VEE visual engineer- ing environment are available from the company's Web site at http.//www hp com/go/hpvee.

About the author Ted Marcopulos is employed as a solution architect in the

Solution Services Division of Hewlett-Pachard Co., in Palo Alto, Calif.

Spectrum editor: Robert Braham

IEEE SPECTRUM A U G U S T 1998