|Views from the orbiting Mars Global Surveyor: Top, July 17: Fog hangs over a 22-mile-wide crater near the south polar frost cap of Mars. The rippled pattern is caused by winds blowing northward from the pole. Bottom, May 1: In the northern Sinus Meridiani, buttes and ridges formed in erosion-resistant rock border a windswept impact crater that was once buried under sedimentary debris. The image represents an area about two miles across. |
All photographs from NASA/JPL/Malin Space Science Systems.
When the space shuttle Columbia disintegrated over Texas on February 1, its sister ship Atlantis
was on deck to ferry a fresh crew and supplies to the International Space Station. Instead, it sits in a hangar at the Kennedy Space Center, jacked up and encircled with scaffolding. There's a cavity where its engines should be, and the nose cone has been popped open. Coming upon it in this state of unreadiness is like catching the Queen of England in her knickersunsettling, but magnificent. Bill Dolan, a 62-year-old "tile tech," takes a glass chisel and removes a gray piece from the ship's gently curving underbelly, then sucks up the remaining crumbs with a vacuum nozzle. Parts from the leading edge of Atlantis's
left wingthe same section thought to have ruptured on Columbia
are lying on a table off to the side. A couple of engineers are running tests on them. It's usual maintenance for a shuttle, says a NASA official, but one could not watch the scene without wondering whether special attention is being given to those parts to make sure a similar accident doesn't bring down Atlantis
on its next flight.
When might that be? Before they could know, NASA engineers had to sift through the charred and twisted remains of Columbia,
spread out over an acre of highly polished floor in a nearby hangar. "The first time I was in here was an experience," says NASA engineer Michael Leinbach, the chairman of the debris reconstruction team. "You wouldn't be human if you weren't moved by what you saw. But now the emotion's pretty well gone. It has become a tremendous engineering challenge and a labor of love." For months he and other engineers huddled in a corner over a life-size, clear Plexiglas frame of the left wing's leading edge, attaching scraps. Gradually the facts assembled themselves until there was no denying them. What brought down Columbia
was most likely foam that broke off from a fuel tank on launch and hit the wing. It was both an obvious cause and yet not easily accepted.
After the accident, NASA officials stoically kept to the line that the period of introspection and reform that inevitably follows such accidents could be compressed into a few painful months, and that the fleet of space shuttles might fly again as early as autumn. But they never said it with real conviction, and Atlantis
most likely won't fly before next spring. With the shuttle being the only vehicle big enough to ferry parts and other supplies to the International Space Station, that outpost will remain in limbohalf built, with a bare-bones crew of two. The human exploration of space is on hold.
So, does anyone care?
In the aftermath of Columbia,
there were few angry calls to end the manned program like those following the Challenger
blowup in 1986. Neither was there much consternation that the entire manned space program might be grinding to a halt. Some pundits attacked, again wondering whether the risk to humans was worth it. But before long the possibility of war in Iraq took center stage, and the dialogue petered out.
Americans still say they want to send people into space, but it's been a long time since they've felt strongly about it, and even longer since they've been inspired by feats of astronaut bravery. The stars of the Columbia
crew, as with all shuttle crews, are not the pilots but the payload specialists, the scientists who carefully nurture the worms and the moss and study how flames burn in microgravity. They tend not to be inspiring. A lecture on moon rocks by geologist and Apollo
astronaut Harrison Schmitt doesn't compare to the moment Neil Armstrong set foot on the moon.
Ever since Apollo 17
returned home safely, the biggest problem for NASA has been finding justification for continuing to spend lots of federal tax dollars. Without a moon race driven by a cold war, the goal has become the pursuit of scientific and technological knowledge. "Imagine knowing that we are not alone, but that life is abundant in our solar system and throughout the universe," reads NASA's 2003 Strategic Plan, which was completed just before the Columbia
accident. "Imagine a world in which long-term weather forecasts are reliable, and natural disasters are predictable and perhaps even preventable." A reliable weather reportnow that's inspiring.
Not that the science isn't worth doing. The problem is that relying on it to justify the enormous expense of sending people into space puts NASA at a rhetorical disadvantage. The lion's share of its $15 billion for 2003 goes to the space station and other manned programs. Only 23 percent falls under the category of space science. Robot probes, which don't need to bring along air to breathe and water to drink and an exercise machine to stave off osteoporosis, cost much less.
|May 26: Layered sedimentary rock exposures in a western Arabia Terra crater show signs of long-term erosion. Much of the erosion may have been caused by wind; the darker areas represent windblown sand. The scene is illuminated by sunlight from the left.|
All photographs from NASA/JPL/Malin Space Science Systems.
Why are people needed? Well, they're reliable when things go wrong. The best example is the Hubble telescope. If astronaut Story Musgrave hadn't fixed the ailing telescope with his own two hands, those spectacular photographs may have been lost to history. Yet, with the money saved from not launching the shuttleat roughly $500 million a popnot to mention the billions for the space station, NASA could have launched a small fleet of Hubbles and still come out ahead.
The people running NASA know full well the public is hankering for something more enduring, for an inspirational trip to Mars. "Any time I go out and talk to people, their question always is, 'How come we don't have plans to go to Mars?' " says former astronaut Shannon Lucid, now NASA's chief scientist. "If I had any interest in politics, I would run on a Mars platform. I'll bet I'd get elected." So why not? Why not make a bold, decisive, risky, hell-for-leather commitment?
Two contrasting arguments never go away when it comes to the space program. The "it's a waste of money" types include fiscal conservatives, those who contend we'd be better off spending the money on the poor, and scientists who can't get enough time on the Hubble. The Mars-or-bust types seem to have read a lot of Arthur C. Clarke's novels. For example, Louis Friedman, executive director of the Planetary Society, told a USA Today
reporter recently that NASA has kept us "trapped in Earth orbit." He has been joined by space entrepreneurs like Eric Anderson, head of Space Adventures, who want the profitable bits of low-orbit space launches. "Operating space vehicles in low Earth orbit is something private industry should do," he says. "Let's make commercial space the main form of space travel, and let NASA do things that only NASA can do, like go to Mars." That argument can be read: Leave the really risky stuff to NASA.
Of all the people urging space planners on to the Red Planet, perhaps nobody has thought more about how to do it than Robert Zubrin. Space exploration started for him, as for many others, as a childhood dream. It drove him to become an aerospace engineer at Martin Marietta. Then President Bush the elder announced in a July 1989 speech that a Mars mission was a top priority for NASA. It was an echo of Kennedy's "We choose to go to the moon" speech in 1962, and for a while it seemed as if the United States might actually send people to Mars in Zubrin's lifetime. In the meantime, Zubrin made it his personal mission to develop strategies for how to get there.
Whatever brief political momentum the president's announcement had generated was gone by the time Zubrin's book The Case for Mars
was published in 1996. The country had fought the first Gulf War, Bill Clinton had taken the White House, and cooler heads prevailed at NASA. The discovery in 1996 that a meteorite that struck Antarctica might contain fossils of Martian microbes briefly rejuvenated the subject, but it soon fell back out of the public conversation. Zubrin's thesis hasn't changed: Going to Mars is not as hard as you might think, provided you avoid the pitfall of developing fancy technology and rely instead on what already exists: good old-fashioned chemical booster rockets.
|May 10: A heavy blanket of dust covers lava flows near Pavonis Mons. The normally rugged surface of the lava flow has been smoothed over by fine dust that settled out of the atmosphere. The sun illuminates the area from the right.|
All photographs from NASA/JPL/Malin Space Science Systems.
As the Apollo
engineers know, chemical rockets have a weight problem: The fuel is heavy in relation to the thrust it provides. It takes a pretty big rocket just to get to low Earth orbit. For a 100-hour, 239,000-mile trip for a landing on the moon, NASA had to build the biggest rockets ever, the giant Saturn V
boosters. The rockets weighed 67 times more than the Apollo
capsule and its crew. Mars, on average, is 593 times farther away from Earth than the moon. More distance means more fuel, which means a bigger rocket, which means even more fuel, and so on.
To get outside this vicious circle, Zubrin had a two-part plan. First, he suggested, send two robot ships to Mars that wouldn't have the burden of carrying humans and all of their life-support gear. Upon landing, robotic machines would begin to manufacture rocket fuel out of native elementsextracting oxygen from the Martian dust. Two years later, the human crew would follow in a separate ship carrying just enough fuel for a one-way trip. They would then set up their ship as a habitat base and use the fuel waiting for them on the Red Planet for an eventual return to Earth in one of the robot ships.
Zubrin's critics say that using chemical rockets is slapdash and doesn't really lower the staggering cost of exploring our solar system. Worse, a conventional rocket trip requires conserving fuel. The route that uses the least fuel isn't the quickest or the shortest and does little to protect the crew from an increased exposure to radiation and other ills of long space voyages.
Not deterred, Zubrin suggests shielding the crew from radiation by storing water in the walls of the ship. To ensure against bone and muscle loss during the 12 to 18 months Zubrin anticipates they would be in transit, he would use the old science fiction idea of rotating the ship to create artificial gravity.
| May 18: A ribbonlike cliff forms one side of a trough in the Zephyrus Fossae region. The debris at the base of the cliff is made up of boulders as big as houses. The terrain is layered in dust, some of which has fallen in landslides and avalanches. |
| May 5: Spidery tracks and streaks created by towering dust devils (see Discover, July 2003) crisscross an open landscape in the southern hemisphere during the early summer season. The image represents an area about two miles across.|
All photographs from NASA/JPL/Malin Space Science Systems.
NASA officials sometimes seem as though they've been asked about Mars one too many times. Fred Gregory, a former shuttle pilot and now NASA's deputy administrator, is a convivial man who appears to get a genuine kick out of working in the space-exploration business. He talks readily about NASA's mandate to explore the far reaches of the solar system, like the Jo-vian moon Europa, where a thin sheet of ice may cover life-sustaining oceans. But ask him about sending people to Mars and an expression of pain flickers across his face: "Mars would be a great place too. But anyplace we went would not be an end in itself."
NASA officials say they are preparing for a Mars trip, even though a specific mission is not in the offing. Before we take this bold leap, they add, we must first do our homework. For all their flaws, the space shuttle and the space station have long been seen as necessary first steps to exploring the rest of the solar system. In this view, Mars is only one of many destinations that NASA is considering. In a congressional hearing last year, one senator lectured NASA administrator Sean O'Keefe on the need to make a trip to Mars. After listening patiently, O'Keefe said: "Establishing visionary goals of where we want to go is a laudable objective, but [first] we need to work on the enabling technology."
For now, a rocket designed specifically to get to Mars is not on the drawing board. The technological cornerstone to NASA's so-called plan to explore the solar system has become an obscure project called, somewhat ironically, Prometheus. NASA scuppered plans to make a big announcement of the project when Columbia
came down, but it's on the tip of the tongue of every NASA planner. The idea is to develop electric rocket engines powered by nuclear fission. A nuclear ship could be assembled in Earth orbit and fire up its reactor only when it was already a safe distance away. Much like a terrestrial nuclear power plant, the reactor would generate electricity, which would then accelerate ions (electrically charged atoms) out the back of the spaceship. An ion rocket would apply a constant, gentle acceleration to the spaceship.
The technology has promise, and it even has a certain sci-fi appeal. The rocket would most likely not be as radioactively messy as past designs because the fission reactor would be entirely separate from the ions that are expelled from the engine. It would also have a far higher "specific impulse" than chemical rockets, which reduces the amount of propellantprobably xenonthe ship would carry. In theory, a Promethean-powered spaceship could be pointed at Mars and just go, with no waiting around for Earth to move into the right position for an orbital-trajectory boost. But NASA is currently working only on plans to use the technology for small unmanned probes that may bypass Mars entirely. "Down the road, we're talking about launching bigger and bigger things into space," says Alan Newhouse, director of the Prometheus project. "When you get to manned missions, you want to get the crew there as fast as you can." In the meantime, there is no prototype for Prometheus, and Newhouse won't target a date for one. "We're looking at concepts for manned missions," he says, "but we still need to get the weight down." NASA's idea of waiting until all the technological pieces are in place before committing to a Mars mission may seem less like a reasonable plan and more like procrastination, the kind of thing you might expect from government agency run by cautious bureaucrats and engineers.
Despite the daring legacy of the Apollo
missions, NASA never was a throw-caution-to-the-wind kind of place. It took President Kennedy to point the space agency in the direction of the moon. Many NASA officials were against it. They fretted that the technology was unproven, that too little was known about how people would fare in zero gravity and whether a safe landing was possible on the moon's surface. Could the country afford an embarrassing failure? Better, they said, to gradually develop the underlying technology. Kennedy brushed aside these worries. Were NASA to make a bold pronouncement about going to Mars, it would be entirely out of character.
|June 26: A 1.4-mile-wide meteor impact crater in the Schiaparelli Basin may once have been full of sediment that eroded to create wavy rings. The mesa top of the crater's center is higher than the stair-stepped rings surrounding it. Earlier in Mars's history, the entire crater may have been at the bottom of a lake. |
All photographs from NASA/JPL/Malin Space Science Systems.
In the years since the moon race ended in 1969, NASA has had plenty of time to do it their way. The space station is supposed to be an enabling technology for manned missions to the solar system, but it's been rife with problems, not least of which is the current dilemma of how to keep it flying without visits from the space shuttle. The shuttle, another big enabling technology, is at the same time both the greatest flying machine ever invented and a costly boondoggle. NASA's original sin was to try to make the shuttle satisfy the requirements of both a civilian space program and the U.S. Air Force, which made the ship far larger and costlier. When the Nixon White House wouldn't give NASA enough money to build a reusable first stage, it switched to the current design, with the orbiter riding piggyback on its own external fuel tank. This less-than-ideal configuration made the shuttle more expensive to launch and more difficult to maintain. It also set the stage for the falling foam problem that most likely destroyed Columbia
The shuttle "was a flawed national policy decision 30 years ago," said John Logsdon, a space policy expert at George Washington University, shortly after the Columbia
accident, "and we're now reaping the consequences." NASA's recent effort to correct this mistake and build an efficient reusable shuttle also turned out to be a costly failure. In 1996 NASA administrator Dan Goldin unveiled the basic design of a single-stage-to-orbit vehicle to replace the shuttle. A team of engineers began refining the design of a prototype, the X-33, and a follow-on vehicle called VentureStar,
but they began to pile on ambitious technical goals, including a lightweight "aerospike" engine with an inverted bell shape designed to improve the efficiency of thrust. When the aerospike and other innovations didn't prove feasible, the whole project collapsed.
The failure of the X-33 seems to have made NASA gun-shy about taking technological risks. "We tried to swallow the whole elephant," says Bill Readdy, head of human spaceflight programs. "Now we're trying to feed the elephant one bite at a time." NASA is putting its efforts behind the Orbital Space Plane, essentially a souped-up replacement for Russia's Soyuz, which ferries crew members to the space station. Because it won't carry cargo, the Orbital Space Plane won't serve to replace the aging fleet of shuttles, for which NASA has nothing in development. Readdy justifies NASA's reliance on the shuttle as a cost-saving measure. "If you're really stingy," he says, "and you've got a car with 50,000 miles on it, you're going to drive it for another few years, aren't you?"
In the post-dotcom, post-9/11 age, there doesn't seem to be any room for another gold-plated government agency. And a perception that much of NASA's vaunted technological prowess gets frittered away on bureaucratic rules and specifications doesn't help. Greg Bennett, chief engineer for Bigelow Aerospace in Las Vegas and a former space station designer, recently ordered a pair of valves for a vehicle he is building to house tourists in low Earth orbit. When the valves arrived, he was struck with déjà vu. The valves he held in his hands, for which his firm paid $500, looked suspiciously like a pair NASA had made for almost $1 million for use on the station. "I can't for the life of me figure out how there's any difference," he says. The difference is that the NASA parts have to meet elaborate specifications that require testing and inspecting and documenting.
NASA might cut through the bureaucratic inertia if it had clearer goals. "If [former NASA head] Goldin had said, 'We need to go to Mars' and had made development of a heavy-lift booster part of that goal, we would have had one by now," says Zubrin. "Instead, they futzed around for five years on the X-33, accomplishing nothing. With Saturn V,
failure was not an option. With NASA today, failure is not a problem."
There's another explanation for NASA's inability to capture the public's imaginationsafety. NASA, like any large institution, has a deeply ingrained safety culture. One of its biggest arguments against sending people to Mars right now is that we don't know how to keep them safe from harm. How would astronauts keep bone and muscle loss on the long voyage to a minimum? How would they survive exposure to radiation from the sun once they moved beyond the Van Allen belts? The arguments are strikingly similar to those against going to the moon in 1960.
And the original arguments could have proved correct. Shannon Lucid says that had any of the Apollo
astronauts been less lucky, they could have been exposed to lethal doses of sunspot radiation. Scientists have a much better handle on sunspot activity now, but in the 1960s solar flare-ups were much more unpredictable. The rule of thumb is still simplewhen you leave Earth orbit, you can die.
Which brings everything back to the space station. "By hugging the rim of our Earth," says Lucid, "we're finding out: 'Is there something we've overlooked? Is there something we need to know before venturing further?'"
It's hard to take a stand against safety. We're the people who require children to wear helmets when they ride bicycles. We equip cars with seat belts, air bags, and antilock brakes. We hold fast-food franchises responsible for scalding us with hot coffee. The safety culture is at odds with our own ideas of what explorers should do. Explorers risk their lives, and sometimes they die. When Columbia
was lost, some people argued that the manned space program should be shut down on the grounds that it was too risky. The surviving families, though, understood that the most fitting tribute to the seven Columbia
crew members who died in the accident would be to stay the course. Yet we want it both waysexploration, risk free.
That's why Lucid is resigned to a long period of cautious development before NASA ventures out into other parts of the solar system. "You have your highs, and you have your daily routine," she says. Going to Mars, like going to the moon, would be a peak moment. "And by the very nature of a peak moment," she says, "it is rare."
NASA's fred Gregory made an off-the-cuff prediction back in the 1980s that the space station would be launched in 2000 and that NASA would go to Mars in 2020. The first guess was pretty close, but barring a presidential edict, it's hard to see how NASA will reach Mars in 17 years. The agency is under pressure to farm out more of its work to contractors. A lot will depend on what private firms do. A few years ago a clutch of rocket companies sprung up to build low-cost launchers, and for a while there was something of a race to be the first to launch a reusable three-man rocket and win the $10 million X Prize. Although the bottom has dropped out of the satellite business, several firms seem close to the X Prize. Others are trying to launch space tourism ventures, including Amazon.com billionaire Jeff Bezos and Bennett's firm Bigelow. If they succeed, they will be halfway to Mars. There is an old adage in the space business: Once you've expended the energy to get into low Earth orbit, you're halfway to anywhere else in the solar system. Perhaps then NASA will go the rest of the way.
Read NASA's 2003 Strategic Plan: www.nasa.gov/pdf/1968main_strategi.pdf