Mars landing to test NASA's prowess

The loss of another Mars craft put a spotlight on the agency's "faster, better, cheaper'' approach.

By DAVID BALLINGRUD

© St. Petersburg Times, published November 29, 1999

PASADENA, Calif. -- In the past when NASA has had this much on the line, this much to worry about, it has always been about astronauts.

The manned moon missions, the first space shuttle flight, the "return to flight" after the Challenger tragedy -- whenever the space agency's credibility was at risk, the safe return of astronauts would define success.

Not this time.

This time, NASA's damaged reputation, and perhaps its long-range plan to explore deep space, will rise or fall on its ability to make a few machines work in a harsh environment 157-million miles from Earth.

A small spacecraft is scheduled to land near the south pole of Mars around 3 p.m. Friday. A signal confirming safe touchdown would arrive at Earth, traveling at the speed of light, 14 minutes and 4 seconds later.

It is an extraordinary, difficult task in the best of circumstances, and these circumstances are anything but. It is hard to imagine a more inhospitable place to succeed: a frozen, uneven, windswept plain of red rock and dust, surrounded by a thin atmosphere of carbon dioxide.

It gets so cold on the Red Planet's surface -- minus 200 degrees Fahrenheit at times -- that NASA engineers worry the rocket thrusters designed to cushion the spacecraft's descent to the surface will freeze and not work. So they devised a way to warm them up, just in case.

For NASA, this mission must work.

Much more than science is riding on the spacecraft called Mars Polar Lander: It has become a test of NASA's policy to explore the solar system at low cost -- NASA Administrator Dan Goldin's much touted "faster, better, cheaper" way of doing more missions with less money.

As Friday approaches, the pressure is building at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The tension on the team is up by several factors," said Richard Cook, the spacecraft operations manager.

Nerves are on edge because of the embarrassment in September.

Mars Climate Orbiter was the sister spacecraft to Mars Polar Lander. NASA's plan called for the orbiter to circle Mars, study its weather, and relay information from Polar Lander back to Earth.

But when Climate Orbiter went behind Mars it did not emerge on the other side. It is presumed to have crashed into the planet because two teams -- one at JPL and the other at a Lockheed Martin -- exchanged vital information in different units of measurement.

The spacecraft had a trio of reaction wheels, devices similar to flywheels, to help maintain its orientation. Twice a day during the cruise to Mars, tiny thrusters on the spacecraft were fired briefly to counteract the effects of solar wind and other forces on the spinning of the flywheels.

The spacecraft team in Colorado used English units to describe the forces imparted by such thruster firings. That data was sent via computer to JPL, where the navigation team was expecting to receive the information in newtons, a metric measure of force.

When the small errors caused by the mix-up were magnified over the 470-million-mile journey, the spacecraft approached too close to Mars and was captured and pulled in by the planet's gravity.

A hurried NASA investigation concluded the same problem does not afflict Polar Lander. A second report, due by Feb. 1, will address lessons learned and recommendations to reduce the probability of similar incidents.

But there was no way to sugarcoat it. It was a shocking blunder, right up there with failing to check the Hubble Space Telescope's mirror before launching it into space.

At least as troubling, however, were the investigators' findings that JPL workers failed to communicate their concerns about the mission, and that navigators had a lack of knowledge about the orbiter. JPL was also faulted for understaffing and inadequate training in the Mars program.

Officials maintain that the metrics problem was not discovered in time because rules for double-checking were not followed, insisting that the space agency's policy of "faster, better, cheaper" missions played no significant role.

"Starting about a year ago, four interplanetary spacecraft were launched in 31/2 months. All four spacecraft worked. That's a fairly impressive record," said JPL Director Edward Stone. "And the cost of those four was one-third the cost of the Galileo mission (to Jupiter)."

But analysts who follow NASA disagree, arguing that shortcuts were taken because the program is increasingly understaffed and crews are overworked.

"They're basically trying to take 15-gallon trips on 10 gallons of gas," said John Pike, director of space policy at the Federation of American Scientists.

NASA's congressional critics are watching, too, making a Polar Lander success even more important.

"People want to get back to having the feeling that we can, in fact, do things like this," said Cook, the mission manager.

"Everything that can be done is being done," said Carl Pilcher, NASA's science director for solar system exploration. "There is no aspect of this mission that is not being re-examined to make sure it is the way it needs to be."

Polar Lander is headed for touchdown roughly 500 miles from the planet's south pole, the first landing in the region. It will descend to the surface using a parachute and thrusters, much like the Viking spacecraft in 1976.

Scientists hope layers of dust and ice will reveal secrets of Mars' past during the 90-day mission. They want to find out what happened to the water that is believed to have flowed across the planet.

Polar Lander is not equipped with a rover vehicle, as the successful 1997 Mars Pathfinder spacecraft was, but it does have a 6-foot robotic arm that will scrape more than a foot beneath the surface. It will take samples of dirt and heat them, testing the vapor for signs of water.

To reach the surface safely, Polar Lander must enter the Martian atmosphere at a precise angle. With the spacecraft moving at more than 15,000 mph, an error of 1 degree could send it skipping off into space -- or into a fiery, fatal plunge through the atmosphere.

Because it will be out of radio contact with Earth during the descent, the spacecraft will operate on preprogrammed instructions during the final minutes before landing. A parachute will open when it is about 4 miles above the surface. At about 1 mile, the spacecraft will discard the parachute and fire its engines to make a controlled landing.

The scientific investigations will begin before the landing. As it nears Mars, the spacecraft will jettison two basketball-size probes that will slam into the surface at more than 400 mph.

"Imagine driving a car into a brick wall at 400 mph and then expecting it to start," said George Powell, a project engineer.

The probes' thin shells are designed to deflect heat and to stabilize and orient the probes in free fall. The shell, less than three-eighths of an inch thick, will shatter on impact. The force of impact will plant the outer frame of the probe solidly on the frozen surface. At the same instant, the tremendous downward momentum will thrust a small tube 3 to 4 feet into the soil.

If all goes well, a tiny, spring-loaded drill will twirl out from the side of that tube into the soil, delivering a sample to a cup inside. The matter will be heated and a laser projected through any escaping water vapor. Wires inside a flexible plastic tether will transmit chemical data for relay back to Earth.

One of the most dramatic mission highlights, however, might be one NASA didn't pay for. The Mars microphone, proposed by astronomer Carl Sagan, who died in 1996, and funded by the Planetary Society, which he co-founded, will give Earthlings their first chance to hear what it sounds like on the surface of another planet.

"The microphone will be able to hear winds, perhaps even a type of lightning within sandstorms, and noises made by the lander, such as the sound of the robotic arm digging for soil samples," says Greg Delory, a University of California, Berkeley, engineer who helped design the microphone. "The most interesting sounds, however, will be those we don't know about yet."

-- Information from Times wires was used in this report.

© St. Petersburg Times. All rights reserved.