PERSPECTIVE ON NASA : Rough Weather for the Space Quest : Loss of the Mars Observer will renew calls for cheaper, low-risk missions. But can a dollar value be put on scientific exploration?

The loss of NASA’s Mars Observer spacecraft promises to fuel an intense debate about the future of the planetary exploration program. We will hear arguments similar to those already voiced by Caltech professor Arden Albee, the project scientist, who is urging an immediate follow-on mission to orbit the red planet. At the other extreme there will be the usual calls to abandon the planetary exploration effort altogether.

As we cope with the immediate shock of losing this flagship mission, our first thoughts are of gratitude that there were no astronauts or cosmonauts on board. What was lost was a complex robotic extension of our human senses, not human lives. The scientists and engineers who invested more than a decade of their careers on the Mars Observer deserve our sympathy and support, but we are most thankful that they still have their lives. Such is the process by which we grieve.

Now we gird for the debate over the future course of the nation’s efforts in planetary research.

One leader of this debate will be the NASA administrator, Daniel Goldin, a former executive of the TRW Corp., who inherited a planetary exploration program that was characterized by a small number of very expensive missions. In addition to the Mars Observer, these missions include the Galileo Jupiter orbiter and probe, which is en route to that planet, and the Cassini Saturn orbiter, currently under construction.

The spacecraft for these missions are designated “Class A.” Each one comprises many redundant subsystems which are intended to reduce the risk of failure to near zero. These are meticulously designed and laboriously tested repeatedly prior to launch. Low risk comes at a very high cost.

The Mars Observer loss occurred in spite of such elaborate risk reduction efforts. Similarly, Galileo’s high-gain antenna failed to deploy after launch. These failures will be cited as evidence that the cost of minimizing risk is too high.

In the past, NASA has dealt with the problem of risk minimization by building twin spacecraft. The cost of the second spacecraft comes at a small fraction of the initial cost. This approach was abandoned for Mars Observer, Gaileo and Cassini as a savings measure.

Goldin has argued that planetary exploration missions could be flown at considerably reduced cost if the instrument package was reduced in scope and if the spacecraft was designed with fewer Class-A systems. As a consequence, NASA would assume a corresponding increase in risk. The result would be more frequent planetary exploration missions at lower cost per mission. The impact of losing one mission would not be as devastating because the investment is diversified.

This approach has strong support within NASA. For example, this year NASA inaugurated a series of what it calls Discovery-class missions. Each mission is required to cost less than $150 million to develop. (The Mars Observer project cost almost $1 billion.) The operations costs of Discovery missions are also to be severely constrained. Many strategic planners at NASA hope that this will be the exploration path of the future. Ultimately the agency hopes to launch one Discovery mission a year. Within a decade, the missions will explore as many as 10 diverse targets, as opposed to a Class A mission, which has only one.

The scientific community has responded enthusiastically to the Discovery mission concept. Last year NASA received more than 80 thoughtful designs in response to a solicitation for prospective Discovery missions. Next year, a few will be selected for further study and development.

The loss of the Mars Observer will add considerable fuel to the fire that Goldin has started. After all, why pay so much to develop efforts to eliminate risk when the big missions are failing anyway? If there were more frequent low-cost missions, the risk would be diversified.

The argument for a small number of cheaper, moderate-risk ventures promises to spread beyond NASA. It may ultimately include the entire arena of federally sponsored research. It will appear in the debates over the space station, the superconducting super collider, the human genome project and most aspects of military research.

At the crux of this big-mission vs. small-mission discussion is the question: What is the marginal cost of increasing the intricacy of a scientific or engineering effort? The concept of marginal cost is well understood in business; every business knows the cost of manufacturing the next incremental unit of production. This cost is quantified by market forces that determine the unit’s price. But the marginal cost of doing science is terra incognita. There is no market to determine the value of the unit. This will be the central issue of the debate.

Ultimately, the loss of the Mars Observer may have a positive effect on society. It will intensify the high risk/low risk argument and will force us as scientists to place a value on our work. Much will be learned. Unfortunately, it will have come at a very severe price.