A Fatal Attraction in Space
Somewhere between Earth and Mars is a great galactic ghoul.
It is an unseen monster that gobbles up spacecraft for lunch and spits out their remains into the cold, dark void.
Over the last four decades, human beings have sent 36 spacecraft toward Mars. Twenty have ended in disaster -- explosions in Earth’s stratosphere, crashes on the Martian surface, or endless spins into deep space.
It’s no wonder that space scientists have nicknamed Mars the “Death Planet.”
Just two weeks ago, Japan conceded the demise of its first and only mission to Mars. Nozomi, “hope” in Japanese, suffered through five years of relentless space storms, breakdowns and miscalculations without ever reaching the planet.
“Space is very unforgiving,” said Louis Friedman, executive director of the Planetary Society, a Pasadena-based space exploration advocacy group. “You can do 10,000 things right, but do one thing wrong, and you are doomed.”
The specter of the Death Planet now looms large as three spacecraft approach the planet over the next month. Beagle 2 -- a British lander launched by the European Space Agency -- is scheduled to touch down today. The United States is preparing to land two Mars rovers, one Jan. 3 and the next Jan. 24.
The stakes for the $800-million twin-rover gamble are enormous. They are the first major test for NASA since this year’s Columbia space shuttle tragedy. The agency has been humbled by that disaster and beset by the failures of two of its last three Mars missions.
This time, NASA’s Jet Propulsion Laboratory in Pasadena conducted unprecedented testing for an unmanned spacecraft. Before their June and July launches, the two probes, named Spirit and Opportunity, were subjected to temperatures of minus-320 degrees Fahrenheit and lights more than twice as bright as the sun. They were bombarded with sounds loud enough to shake paint chips from test-chamber walls and rumble the ground outside like an earthquake.
Thousands of simulated landings were run on a sophisticated computer model. A third rover was driven over mock Martian terrain -- a playpen of black sand and rock in the dusty Pasadena hills. Budgets were busted to look at endless danger scenarios.
But project engineers and scientists retain their respect for a worthy adversary: the unknown.
“All kinds of statements of engineering certainty, both in this business and other businesses, have turned out to be wrong, because the devil you didn’t know got you,” said rover project manager Peter Theisinger.
The undisputed masters of Martian disaster were the Soviets. Combined with the single failed Russian launch in 1996, they have had 14 failed missions in 18 tries.
They launched the first five attempts to reach the Red Planet, beginning in 1960. Two crashed back to Earth before achieving Earth orbit, the first step on a Mars mission. Two exploded in Earth orbit, and one lost its ability to transmit radio signals after traveling 66 million miles.
Flawed computer chips, software bugs and pyrotechnic calamities became the hallmark of the Soviet Mars program, which failed to achieve a single unqualified success.
A 1971 Soviet lander descended too steeply and crashed on the Martian surface. Its twin touched down safely ... for 20 seconds, after which it was enveloped and destroyed by a massive dust storm.
They launched Sputnik 22, an intended Mars “fly-by,” at the height of the 1962 Cuban missile crisis. The craft exploded in Earth orbit, raining down debris that triggered U.S. early warning radar systems, nearly provoking a nuclear conflagration.
In 1996, the Russians tried to revive a planetary-exploration program with help from European collaborators. That probe also crashed backed to Earth. No one knows why.
Competence was not at issue -- the Soviets were the kings of Venus, achieving 15 successful missions to Earth’s closest neighbor.
“They had the systems in place, but Mars defeated them,” Friedman said.
Bruce Murray, emeritus professor of planetary science at Caltech and former director of JPL, said it was a young child who conjured the image of a great galactic ghoul in space.
“It’s a joke, but it’s no joke about the difficulty in going out that far,” he said.
Japan’s Nozomi is the ultimate Martian hard-luck story -- and all it was trying to do was park in Mars orbit.
For five years, it seemed to demonstrate how dogged determination and ingenuity could overcome an unremitting stream of bad news.
The problems began right after the craft was launched July 4, 1998 -- it veered off course and was forced to burn precious fuel to correct its flight path. Nozomi then lacked sufficient fuel to brake into Martian orbit, and zoomed past its target in October 1999. Engineers recalibrated its trajectory to ease it into orbit more gently, a move that would take four years and two additional trips around Earth.
In April 2002, a solar flare knocked out Nozomi’s power, freezing its remaining fuel, and necessitating a last-ditch gambit. Flight engineers turned the probe’s power system on and off hundreds of times as Nozomi passed near the sun, trying to tap solar energy to jump-start the system. The plan worked.
But a simple electrical short in the navigation system spelled the probe’s doom. It barely missed Mars this month, passing in the endless night of space.
Landing on Mars is even harder.
So many landers have failed that the mission leaders have been forced to adopt a Rube Goldberg-like combination of heat shields, parachutes, retro-rockets and air bags.
A combination of technologies is necessary, yet each adds a layer of complexity that heightens the prospect of catastrophe.
Moon landings are a breeze in comparison. With no atmosphere to throw them off, retro-rockets can reliably guide a craft to a soft landing.
While the Martian atmosphere is only 1% as dense as Earth’s, it can still burn up a spacecraft in seconds and generate gusts of wind that can blow it off target.
So Beagle 2 and the twin U.S. rovers will all use multipart descents, starting with heat shields for about four minutes, followed by parachutes. Even with a parachute, the crafts slow only to about 170 mph, like “a speeding Indy 500 car going straight down,” said Rob Manning, who leads the American descent and landing team.
A few seconds before landing, massive air bags inflate around the landers. The U.S. crafts then switch on retro-rockets, blasting downward a mere three seconds before impact.
At a height of about 40 feet -- or for Beagle 2, an instant before it touches down -- the cushioned crafts are dropped; the U.S. rovers may bounce as high as a four-story building and travel up to two miles before coming to what NASA hopes will be a safe rest. NASA calls the descent “six minutes of terror.”
Compared with other nations’ efforts, the U.S. Mars program has enjoyed phenomenal success -- just five disasters in 16 launches.
In 1975, the U.S. became the first country to successfully land spacecraft on Mars with Viking 1 and 2. In 1996, Pathfinder, the first Mars rover, proved that robots could be surrogate explorers on distant worlds.
Global Surveyor and Odyssey, the most successful orbiters, are still mapping the Martian surface and were crucial to the selection of landing sites for the current missions.
But “failure is always lurking out there,” said Steven Squyres, a Cornell University geologist and one of two lead scientists for the U.S. rovers. Even getting off the ground is risky -- one in 20 spacecraft blow up on launch.
JPL geologist Matt Golombek added: “There’s a dozen ways to die -- actually a hundred. All it takes is one.”
Indeed, the U.S. has committed some stupendous blunders.
In 1999, Mars Climate Orbiter burned up in the Martian atmosphere because a single computer programmer used English units, rather than the metric units used by the other engineers, fatally confusing the device.
That same year, Mars Polar Lander was hovering about 300 feet off the surface when sensors malfunctioned, telling the lander that it had reached its goal and shutting off the retro-rockets. It dropped like a rock.
The problem could have been averted with a single test -- lost in the frenetic rush of launch preparations, Murray said.
Project scientists often need months to recover from such dismal moments.
In 1983, Arizona State University geologist Phil Christensen was just out of graduate school and had been selected for a plum job -- heading a team of scientists to build a thermal-emission spectrometer. The device creates maps by measuring the “heat signatures” of rocks and soil. It was considered crucial for finding signs of life.
He worked day and night for nine years. The unique multimillion-dollar tool went in the Mars Observer orbiter launched in 1992. Just as the craft was approaching Mars orbit, Christensen got a call telling him the Observer was lost.
“I had never experienced a more devastating moment,” he said.
The problem was simple, yet fatal. Pressurized fuel tanks leaked a minute volume of fuel through valves. The leaked fuel exploded, sending the craft into an uncontrolled spin.
“Ten years of my life wasted because someone forgot that valves leak,” he said.
Despite its treacherous history, Mars remains endlessly alluring.
“Because Mars draws us to it with such power, we’ve tried more difficult things with it than anywhere else,” Squyres said.
Disaster is, after all, an inherent byproduct of great discoveries. “Think about 16th, 17th, 18th century exploration of the oceans,” Friedman said. “How many shipwrecks went to the bottom of the sea? We don’t remember them because we remember the great explorations.”
No matter how rigorous the testing, some space shipwrecks may be inevitable, because you can’t judge an approach until it succeeds or fails, Theisinger said. “Ultimately it’s only life experiences that tell you, ‘We tried this -- it worked. We tried this -- it didn’t,’ ” he said.
Even devices that have worked before, such as the landing system on the twin rovers, require a leap of faith, due to what John Pike, an aerospace expert with GlobalSecurity.org, called “the tyranny of small numbers.”
There have been so few Mars missions that any disaster could be considered a freak event, any success a random triumph.
Yet NASA’s Mars scientists exude a sense that every lapse exposed makes the next mission all the more likely to succeed.
“For a place filled with smart people, sometimes we do things that aren’t too smart,” said Tom Shain, logistics manager for the current U.S. missions. “But, by God, we learn a lot from our failures.”