Mars Rovers Ready to Roam

After three years of grueling and rushed construction, NASA officials and engineers said Saturday they are confident two robotic rovers they are about to send to Mars are ready for their perilous journey.

One Mars Exploration Rover, now packed into its heat-protected capsule and sitting atop a Delta II rocket on launch pad 17A here, is scheduled for launch at 11:05 a.m. PDT today. The other, still undergoing final testing in a clean room at Kennedy Space Center, is set to launch June 25. Both are to arrive on the surface of Mars in January to seek traces of past water and determine whether Mars was ever hospitable to life.

Still stinging from the loss of two Mars probes in 1999, NASA’s chief of space science Ed Weiler stopped short of predicting success for the missions, warning that Mars has long been a graveyard for spacecraft. Of 30 missions sent since 1960, 18 have failed. “They don’t call it the death planet for nothing,” Weiler said.

But he promised that NASA has not made the same mistakes -- spending too little and staffing too lightly -- blamed for the 1999 failures. “This time, we won’t be accused of scrimping and saving,” he said. “We spent $800 million to get this right.”

The rovers were built on a rushed schedule of three years instead of the usual six or seven to take advantage of an especially good launch opportunity this year as Mars gets as close to Earth as it will for decades.

To overcome the time crunch, NASA spent $100 million more on the project than planned. The dozens of Jet Propulsion Laboratory employees who have been living at Cape Canaveral since late winter to assemble and test the rovers have worked nearly every weekend.

Though exhausted, many JPL team members are starting to relax now that both spacecraft appear ready for launch. “We’re in the glide path,” said Matt Wallace, who heads the assembly and testing team and called the construction of two complex spacecraft in such a condensed period something that had “never been done before at JPL.”

“One is challenging enough. A lot of us had our doubts about pulling two off,” said Thomas Shain, who oversees logistics for the project and was responsible for bringing the rovers and their accessories from JPL to Cape Canaveral in three nonstop, 60-hour cross-country truck convoys that he called “the first 2,600 miles of the trip to Mars.”

Adding to the pressure, JPL engineers were forced to partially disassemble both rovers just seven weeks before launch after a problem was detected in cabling that could have shorted out important electronics.

The repair required taking apart rovers that had been put together with surgical precision and the setting off of pyrotechnic charges that were not to have been used until the spacecraft unfurled itself on Mars. “That was not only painful, but a challenge,” said Paul Hardy, the lead mechanical engineer on the assembly team.

Hardy also oversaw the packing of the golf cart-sized rovers into their much smaller landing capsules, sometimes with only millimeters to spare. The rovers fold, origami-like, into a smaller configuration with their solar panels neatly folded and their six wheels tucked beneath them. After their air bag-cushioned landing, the “petals” of the lander will open and the rover will stretch out, look around and then respond to commands from JPL.

Anxious engineers said they were ready to launch Thursday, a previous launch date that was postponed so more safety reviews could be conducted. The safety reviews have all checked out and a Thursday launch dress rehearsal went so smoothly under sunny skies that project manager Pete Theisinger said he wondered why the rocket couldn’t have just taken off.

With the health of the spacecraft and rocket checking out, workers here are most worried about the weather -- the low clouds and thunderstorms that have been rolling in every hot and humid afternoon.

Joel Tumbiolo, a launch weather officer at Cape Canaveral Air Force Station, predicted a 60% chance that thunderstorms would cause him to scrub the launch. Air Force rules prohibit a launch if thunderstorms are within 10 miles of a rocket’s flight path.

The spacecraft’s launch window is a mere second long and occurs at 11:05:55 PDT. That window offers an ideal geometric trajectory toward Mars. The rocket cannot depart a second sooner, Baez said, because the rocket is preprogrammed and its trajectory cannot be adjusted. A second launch window occurs at 11:44:07 PDT.

If those two windows are missed, engineers will attempt to launch the rocket Monday and keep trying until the launch period closes June 24. The chance of storms starts to fall by Tuesday, Tumbiolo said.

The launch can’t come soon enough for Steve Squyres, a Cornell University planetary geologist and the chief scientist for the instruments on the rovers. He started working on the instruments more than 10 years ago; they were supposed to fly on a canceled 2001 rover project.

“We’re ready to go,” Squyres said. “We’re really ready to go.”