Viewpoint

With funding becoming increasingly scarce, why should the United States government support

Spacecraft Exploration of Deep Space

by Clark R. Chapman, Ph.D.

The desire to explore has driven the history of modern civilization. The United States itself grew from explorers' exploits. Since polar explorations a century ago, uncharted lands have diminished to slivers. Earthbound frontiers remain, like the ocean depths and the human brain. But for many, the urge to explore now focuses on outer space.

The 1960s conquest of the moon fueled a broad assault on the cosmos. Spacecraft launched into Earth orbit peered ever more sharply and deeply into the universe. So-called "deep space missions" were launched to actually go there, to the nearer planets. For nearly 40 years we have traveled vicariously as camera-equipped, robotic spacecraft visited every planet except Pluto, looked down on the sun's poles, and flew past (or even orbited) some asteroids, comets, and planetary moons.

One day astronauts and cosmonauts will venture beyond the moon. Today, robotic spacecraft beam the sights — and even sounds, tastes, and smells — of faraway worlds back to our laboratories and living rooms. Why do we explore the solar system? What have we learned? After headlined failures of Mars-bound spacecraft, where do we go from here?

Interplanetary space is vast and empty. Even from the midst of the asteroid belt, one could hardly see with naked eyes more than a few faint asteroids among the myriad stars. The biggest Earthbound telescopes, sensing wavelengths spanning from the far-ultraviolet to radio, tell us much about the solar system, yet they pale when compared with getting up close. A big telescope might transform the 34-kilometer-long asteroid Eros from a speck of light into an elongated blob of light. But, after orbiting 35 kilometers above Eros, the Near Earth Asteroid Rendezvous (NEAR-Shoemaker) spacecraft zoomed to within 5 kilometers of the surface in October, imaging millions of boulders the size of a small house!

Rewards are greater if a spacecraft can land and return a rock or ice sample for detailed laboratory analysis. We can "smell" alien atmospheres with sophisticated gas analyzers, seismically "hear" planetquakes reverberating deep within a body, or probe the precise isotopic chemistry of materials collected from a body's surface.

Why do we want to do such things? Simply this: to satisfy our curiosity. As a child learns life by playing, so explorers — whether Lewis and Clark, Charles Darwin, or modern-day space scientists — comprehend issues facing our species by addressing nature's mysteries.

Like a visitor to an exotic culture, a planetary researcher can test whether terrestrial "truths" are really universal or reality is unimaginably richer. We now know that a supposedly Earth-like planet, Venus, has the hottest surface of all, while airless Mercury, even closer to the sun, may have ice at its poles. Such marvels compel us to re-examine our own planet's history — ancient epochs of an ice-covered "snowball Earth" and even mini-ice ages during the brief history of the human species. How can chilly Mars, receiving just 40 percent of the sunlight falling on Earth, sport running water on high-latitude, poleward-facing slopes, as detected in recent pictures from the Mars Global Surveyor? Discovery that a frigid but tidally flexed moon of Jupiter might harbor an ocean as voluminous as Earth's reinforces the new idea that our planet's internal heat, not sunlight, might have fostered the cradle of life in the black depths of our seas.

Some political realists say that the space program was motivated solely by Cold War politics and remains a pared-back welfare program for scientists and space buffs. Those who secretly marvel at the cosmos are obliged to restate the trickle-down economic impact of space exploration on modern society, from breakfast foods to miniature electronics. All that is true: Vast expenditures on astronaut safety and miniaturization of components to withstand the harsh space environment have spurred widely applied technological breakthroughs. And we surely gain comparative perspectives on our own planet's behavior which are responsible for the weather- and geology-related disasters that we suffer.

But researchers really crave deep space missions to see what's on the other side of the mountain, a motivation that has served us well since the Renaissance. And to learn why we're here, where we came from, and whether we are alone — a quest that consumes individuals and humanity as a whole. As many adopted children seek their biological parents to satisfy a sense of identity, so the human psyche yearns to satisfy a primal need to learn about our origins and destiny, the secrets to which may well lie in understanding planetary systems.

How's it all going? Of course, space exploration has fallen short of optimistic extrapolations from the pace of 30 years ago. If it had not, we would now have colonies on Mars. However, much of the public abandoned the astronauts' lunar golf games. Then the expensive Viking landers failed to find life on Mars. The deep space program suffered further declines in the 1980s thanks to larger cultural forces. The public increasingly sought short-term returns incompatible with the long durations of interplanetary missions. And rising deficits threatened budgetary cutbacks and phase-outs that were only partially thwarted. All but a couple of the "logical next steps" of planetary reconnaissance missions were rejected for new-start funding or axed part-way through their development. The glorious adventures of the Voyagers, swinging from Jupiter out to Saturn, Uranus, Neptune, and beyond provided through 1989 a false sense that the planetary program was robust, although this grand tour was actually a realization of much earlier planning and technology.

Deep space exploration can never yield immediate returns for the next quarterly or annual report. In 1977, my proposal to participate on the imaging team of the Galileo Jupiter mission was accepted. Indeed, I was one of a few "youngsters" added to a more experienced team. The mission was to be finished a decade later. But, because of the vagaries of space politics, Kepler's laws of planetary motion, and the tragic explosion of the Challenger space shuttle, Jupiter arrival was delayed a dozen more years. Indeed, Galileo is still — 23 years after the first meeting of recently selected Galileo scientists — cruising among Jupiter's enigmatic moons, returning pictures and data about Io's incessant volcanism and Europa's baffling ice ridges.

Those who would privatize space exploration must contend with years and decades of commitment, hard work, and minimal return. The risk of failure is great. And the yield is basic scientific knowledge, which often must gestate for years or even decades before fostering bankable profits. Such realities require that governments underwrite space exploration, even if phases are nominally carried out by private enterprise.

The recent failures of several Mars missions can be ascribed to a bold experiment by NASA that successfully resurrected a downwardly spiralling program. Missions had gotten large and expensive but few in number as Congress and the White House repeatedly said "no." By 1990, the only remaining missions were the already launched Galileo and Magellan spacecraft, and the Cassini mission, which will fly by Jupiter this December en route to a 2004 encounter with Saturn. (And the ill-fated Mars Observer, lost in 1993, was originally conceived as small and cheap but had ballooned in cost before launch.) But what about the sun? The outer planets? Pluto? Comets and asteroids? Mercury? Indeed, what about the moon, to which no spacecraft had returned since the Apollo 17 astronauts departed? They might all have remained terra incognita.

Instead, NASA mandated annual launches of spacecraft that would be "faster, better, cheaper," a slogan in tune with the political times. Cutting expenses (chiefly people's time) and using riskier but more capable new technology became the prime directives among NASA's managers.

Indeed, the 1990s saw many more launches. Many of these simpler missions successfully met their narrower objectives. The combination of successful spacecraft (some old workhorses and the cheaper, leaner ones) has returned data that continue to excite scientists and the public alike. Pathfinder's rover wheeled among martian rocks. Unexpected boulder fields have been found on Eros. Large polar deposits of ice were not found on the moon, but the negative news will profoundly shape the future course of lunar exploration. Galileo revealed Jupiter's large moons to be stunningly complex, each different from the impressions gleaned from Voyager's brief flybys two decades ago.

However, even as data streamed back from asteroids, Mars, and the moon, scientists and engineers retrenched, working overtime on fewer funds and with less back-up help than had been usual in trying to propel complex, cutting-edge systems across interplanetary space. The post-mortems of last year's failed Mars missions all agree that the pendulum toward "faster, better, cheaper" had swung too far. But there will be no conservative, expensive return to the space behemoths that were on the drawing board in the 1980s. The future may instead see a better balance that will continue deep space exploration, but a bit more robustly, thus enabling us to probe issues that have haunted mankind since our species first wondered about our place beneath the starry skies.

Spacecraft are currently en route to Comet Wild 2 and to the glorious Saturn system, and spacecraft are being designed to return to Mercury and Europa. Other mission concepts are under way. Southwest Research Institute scientists are involved in many of these deep space missions, so we may confidently expect to see the solar system's secrets unfold in future issues of Technology Today®. We at SwRI, and our colleagues around the world, continue to explore space because it is a global adventure that captivates us all. The old adage is wrong: There is something new under the sun, but we must keep exploring in order to find it.

Comments about this article? Contact Chapman at (303) 546-9670 or cchapman@boulder.swri.edu.

Published in the Fall/Winter 2000 issue of Technology Today, published by Southwest Research Institute. For more information, contact Maria Martinez.

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