NASA Has a New Mission--Focus on Fragile Earth
The nation’s space agency, typically identified with trips to the moon and distant stargazing, is turning its telescopes back toward Earth in an unprecedented probe of the planet’s ability to withstand environmental pollutants.
Displaying its traditional knack of going where the money is, the National Aeronautics and Space Administration has joined a slew of federal agencies competing for research dollars in the name of ecology.
Thus far, NASA appears to be winning the competition. So critical is the need for a view from space that the bulk of a $1.034-billion federal budget for global environmental research next year is slated for the agency. Such research is considered imperative because man is despoiling the Earth at an unprecedented rate.
“I think NASA realizes that in looking at the planets, it should have included Earth,” said F. Sherwood Rowland, a UC Irvine scientist who has pioneered research into the depletion of the protective ozone layer.
From providing clues to global warming to gauging acid rain damage, NASA satellites and researchers are expected to produce information that will help provide early warning signals of environmental trouble and enable scientists to predict more accurately the toll pollutants will take on the planet.
“We’ll be able to do very detailed environmental ecology science from orbit,” said Barrett Rock, an associate professor of forestry at the Institute for the Study of Earth, Oceans and Space at the University of New Hampshire. “It will be very exciting.”
Already, NASA researchers and NASA-built instruments have measured the loss of the ozone layer, taken a 10-year temperature of the planet (there was no net warming), observed the clearing of tropical forests in South America, and helped confirm an essential component of the greenhouse theory.
Fortunately for NASA, the scientific demand for this global perspective coincides with the agency’s need for a politically popular mission. In asking for money from a budget-conscious Congress, NASA has been pressed to produce practical applications for its programs.
Although the bulk of the agency’s efforts will continue to be oriented away from Earth, strong political support for environmental research is giving NASA’s earth science division unprecedented internal attention and support. Scientists and environmental activists praise the new focus but lament that it did not come sooner.
Attuned to the political advantages of taking on the environment, the agency has launched “Mission to Planet Earth,” a catchy label for a refocused and expanded earth science program. The mission’s centerpiece is a proposed $17-billion, 15-year satellite project known as the Earth Observing System.
A tandem of two satellites will be aimed at helping scientists understand how the Earth’s oceans, atmosphere and vegetation interact. Many of the questions seem simple, but their answers have been elusive.
How much vegetation is left on the planet? At what rate is it vanishing? How are the losses contributing to climate change? What roles do the clouds and oceans play in the temperature of the planet? Will clouds help forestall the devastating warming predicted by many scientists? What portion of the Earth’s forests are dying because of acid rain? Are the polar icecaps shrinking?
For scientists accustomed to looking away from the Earth, the challenges are enormous.
“With all the planets I have looked at, I have never seen anything as complicated as the Earth,” said Gerald Soffen, a NASA planetologist who has devoted most of his 29 years at NASA to looking upward.
“The thing that complicates the Earth, of course, is the water and the biology, especially humans. It is just mind-boggling. I can’t imagine how a foreign being would cope with studying the Earth unless he were living here.”
Astronauts, of course, have been looking down at the Earth for years, and their reports and photographs already have contributed to the global view of the environment and a better understanding of ocean movement. Environmental activists say NASA photographs often are their most useful tools in drumming up interest in global environmental problems.
Not surprisingly, these space-based observations tend to be disheartening.
Former astronaut Paul J. Weitz, now deputy director of the Johnson Space Center, said he noticed that global air pollution had increased “markedly” between his 1973 and 1983 flights, particularly around the Equator. When he returned to Earth, he said, he was told the “smoky” band he saw was created by the burning of forests.
Water pollution also is evident from space. On one of his flights, Weitz said, he noticed a bluish-green patch spilling into Lake Superior. Back on Earth, he learned it was effluent from a steel factory.
Former astronaut George (Pinky) Nelson said he was appalled at the pollution over Mexico City. He could not see the ground through it. Just as disturbing was the view over Madagascar, where it was plainly evident to Nelson that the largest harbor was disappearing. Year by year, he said, more and more silt is spilled out from the island as its forests are cleared for agriculture.
But the “most dramatic” sight from space was the nighttime glow of fires from the burning of rain forests, Nelson said. Much of South America seemed ablaze.
“One of the impressions you get from space is the impact of man is everywhere but still small,” said Nelson, now assistant provost and astronomy professor at the University of Washington in Seattle. “The impression you get is that it is probably not too late (to conserve) but we ought to do something in fairly short order.”
More troubling to Nelson was the appearance of the atmosphere. “The atmosphere from space looks very fragile,” he said.
As compelling as such observations may be, they do not provide the kind of measurements scientists need to assess the long-term impacts of pollution. Satellites are needed to see where the eye cannot. As the builder of hardware, NASA is slated to receive $661 million--more than half of the eight-agency budget for global research--in the 1991 budget now before Congress.
The proposed Earth Observing System, tentatively scheduled for launch near the end of the decade, would carry instruments that can measure the depth of vegetation, not just the cover. They would measure not only the temperature of the planet--weather satellites recently accomplished this--but also gases in the atmosphere, cloud cover, vegetation, the movement of the oceans and the energy exchange between Earth and space.
The spacecraft would be part of NASA’s contribution to the U.S. Global Change Research Program, a coordinated effort of several government agencies to provide a scientific basis for national and international actions to curb planetary pollutants.
President Bush has hesitated to take action to stem global warming because of lingering uncertainties about whether nature on its own can counteract some of the destructive forces of man.
A minority of scientists believe increased clouding may compensate for gases that cause global warming by reflecting sunlight back into space. But most scientists believe that such gases as carbon dioxide and methane eventually will push temperatures upward by trapping heat on the planet, possibly leading to more hurricanes, droughts and other climatic disruptions.
NASA scientists say satellites will provide data that can be inserted into the computer greenhouse models to clarify the threat. By taking a variety of measurements, the instruments will help show how the forces of nature are intertwined and how pollutants will change the planet.
While the burning of forests emits carbon dioxide--a greenhouse gas--the planting of forests reduces the gas because it is absorbed by trees. Oceans also absorb greenhouse gases and clouds can both raise and lower temperatures.
Simply taking a temperature reading of the planet would be akin to a medical physical in which a physician puts a thermometer in the patient’s mouth and does nothing else.
“If you want to study global warming, it’s nothing to (just) measure the temperature,” said Charles Elachi, assistant laboratory director of the Office of Space Science and Instruments at NASA’s Jet Propulsion Laboratory.
Satellites already are helping scientists learn about the health of forests. Sensors aboard satellites can see the reflection of sunlight off a forest canopy, and scientists can tell from that reflection how much moisture and chlorophyll--the green pigment found in plant cells--remain in the forests. These satellites have revealed that forests in the Northeast are far more damaged by acid rain than anyone had guessed.
Rock, the forestry professor at the University of New Hampshire, said the instruments in use for determining damage to forests are akin to a child’s box of crayons that contains the basic colors. “If you want to color a picture with those crayons you are hard-pressed because they do not portray all the colors of nature,” Rock said.
The instruments proposed for the Earth Observing System would have the advantage of a giant box of crayons. They would distinguish far more precisely the kind of destruction in a forest, from acid rain caused by the burning of coal to damage inflicted by a beetle.
“It is going to be a huge step forward, a huge advantage in being able to monitor the environment and actually watch damage as it develops and to know . . . how severe it is,” Rock said. “We’ll also be able to map progression of atmospheric pollutants and watch the reaction of the vegetation to these pollutants.”
Of course, satellites alone are not enough to study the Earth. Satellites have measured the extent of ozone loss, but NASA’s major contributions toward the understanding of ozone depletion have been made by researchers working on the ground.
Congress has been receptive to NASA’s global research efforts. “The Mission to Planet Earth has strong support,” said Rep. Bill Green (R-N.Y.), ranking minority member on the House Appropriations subcommittee that oversees NASA’s budget.
The congressman credits Congress with pushing NASA to do more global research, but acknowledges that the agency has a self-interest in its “Mission to Planet Earth.” “From NASA’s point of view,” Green said, “it has the advantage of developing another constituency for the space program--the environmental community.”
A different set of political considerations helped lay the foundation for “Mission to Planet Earth” eight years ago. Third World nations were complaining at the time that the United States was militarizing space, and American officials feared a 1982 U.N. conference on space would become a stage for their complaints.
After initially deciding not to attend, the Reagan Administration changed its mind and asked NASA to put together a group of private scientists to recommend a set of peacetime space objectives to take to the Vienna conference. The objectives included research on the ozone layer.
The need for more global research became painfully obvious when British scientists reported in 1985 that the ozone layer over Antarctica had thinned. The stratospheric ozone layer protects life on Earth from the harmful effects of ultraviolet radiation. A NASA satellite subsequently confirmed the depletion. Ironically, the space agency then discovered that its satellites had detected the ozone depletion several years earlier, but a computer had rejected the finding as an anomaly.
While the world fretted about the atmospheric shredding, NASA fretted about its future. The loss of the Challenger in 1986 had plunged the space agency into a period of introspection.
With the shuttle program grounded, a NASA committee headed by former astronaut Sally Ride convened to suggest a course to revive the embattled space program. “Mission to Planet Earth” was among the recommendations by Ride’s panel.
“It’s hard to say whether ‘Mission to Planet Earth’ would be realized if the Challenger (disaster) hadn’t happened,” said a NASA official who asked not to be identified. “Obviously, when NASA did some soul-searching and asked, ‘What should we be doing?’ the answer was obvious that we should be looking at Earth.
“In having to soul-search, it took the agency’s mind off just being a transportation company, as it was becoming . . . NASA had been on the wrong road for some time and was pouring a lot of money into what was basically a rocket and not enough money into what was on top of the rocket.
“We were just going through the motions of going into space and coming back without putting a lot of thought into why we were there in the first place.”
Shelby G. Tilford, director of NASA’s earth science and applications division, said advancements in computer technology and scientific knowledge, as well as the new political will, propelled the Earth Observing System forward.
Politically, he said, it will be difficult for Congress to do anything but provide research funds.
“In many cases, supporting this is like supporting motherhood,” said Tilford.
