Vision and Voyages for Planetary Science in the - Solar System ...

TECHNOLOGY: PORTAL INTO THE SOLAR SYSTEM
Ongoing missions underscore the value of past technology investments. For example, Dawn’s
ion propulsion engine is the essential enabling component of its unique mission to investigate two of the
largest asteroids. After a flight of nearly 4 years, Dawn will arrive at 4 Vesta to spend approximately a
year, starting in the summer of 2011, making detailed observations of 4 Vesta, after which the spacecraft
will cruise for another 3 years toward its second asteroid destination, 1 Ceres. At 1 Ceres in 2015-2016,
Dawn will conduct another complete scientific investigation. Such a two-asteroid mission would not
have been possible using classical chemical propulsion. Years ago, analytic studies showed that
continuous thrust, high specific-impulse propulsion opened up many different mission opportunities,
including missions with multiple targets. These studies triggered the technology development program
that resulted in the ion engines that are currently propelling Dawn toward 4 Vesta.
The Mars Exploration Rovers, now in their seventh year conducting scientific observations while
roaming the Red Planet, benefited immensely from significant precursor technological investments in
both mobility systems and the scientific payload. The story is essentially the same for all pioneering
robotic planetary missions: They would not have been possible, and would not have produced such
extraordinary results, without the visionary technology developments that enabled or enhanced their
capabilities.
Continued success of the NASA planetary exploration program depends upon two major
elements. It is axiomatic that the sequence of flight projects must be carefully selected so that the highest
priority questions in solar system science are addressed. But it is equally important that there be an
ongoing, robust, stable technology development program that is aimed at the missions of the future,
especially those missions that have great potential for discovery and are not within existing technology
capabilities. Early investment in key technologies reduces the cost risk of complex projects, allowing
them to be initiated with reduced uncertainty regarding their eventual total costs. Although the need for
such a technology program seems obvious, in recent years investments in new planetary exploration
technology have been sharply curtailed and monies originally allocated to it have been used to pay for
flight project overruns. As already stressed in Chapter 9, it is vital to avoid such overruns, particularly in
flagship projects.
In the truest sense, reallocating technology money to cover short-term financial problems is
myopic. The long-term consequences of such a policy, if sustained, are almost certainly disastrous to
future exploration. Metaphorically, reallocating technology money to cover tactical exigencies is
tantamount to “eating the seed corn.” The committee unequivocally recommends that a substantial
program of planetary exploration technology development should be reconstituted and carefully
protected against all incursions that would deplete its resources. This program should be
consistently funded at approximately 6-8 percent of the total NASA Planetary Science Division
budget. The technology program should be targeted toward the planetary missions that NASA intends to
fly, and should be competed wherever possible. This reconstituted technology element should aggregate
related but presently uncoordinated NASA technology activities that support planetary exploration, and
their tasks should be reprioritized and rebalanced to ensure that they contribute to the mission and science
goals expressed in this report. The remainder of this chapter will discuss the specific items that should be
addressed by this reconstituted technology program.
From Laboratory to Spaceflight
Given an appropriate technology program budget, the way in which the monies are allocated to
the different phases of technology development should be informed both by the lessons of past efforts at
technology infusion, and by the guideline that any technology to be used on a flight mission should be at
Technology Readiness Level 6 prior to the project’s Preliminary Design Review. The technology
readiness level (TRL) is a widely used reference system for measuring the development maturity of a
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