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Smith and Goldstein
Phoenix Mars Lander principal investigator Peter Smith and project manager Barry Goldstein discuss the spacecraft’s planned landing just a few hours before touchdown, as a video animation of the landing plays behind them. (credit: J. Foust)

A second chance at Mars

It was supposed to be difficult. Dangerous. Death-defying. In the weeks and days leading up to Sunday’s scheduled landing of the Phoenix Mars Lander spacecraft, project officials, scientists, and others made it clear in no uncertain terms the challenge they faced. Landing a spacecraft on the surface of Mars was no easy feat, a claim backed up by a historical record with more failures than successes. Any number of things, they warned, could happen to either damage the spacecraft or lead to its loss altogether. Moreover, hanging over Phoenix was the specter of its heritage: hardware built for a 2001 lander mission that was cancelled after another lander with a similar design, the Mars Polar Lander, crashed while landing in December 1999.

And yet the landing has turned out—at least as of about 24 hours after touchdown—remarkably well. The spacecraft landed in the northern polar plains of Mars almost exactly as planned and immediately began returning data and images, to the irrepressible delight of everyone involved with the project. While the project team prepared for any number of contingencies, none were needed, and scientists were already thinking ahead, planning image panoramas and preparing to use the spacecraft’s robotic arm, designed to dig into the surface in search for water ice. It was a pleasant and positive surprise for a mission that carried with it more than its share of hopes and concerns.

From anxiety to elation

Days before landing, the atmosphere surrounding the project could best be described as anxious. While the spacecraft was in good condition and on course, the uncertainty about what would happen when the spacecraft arrived was clearly on everyone’s minds. The fact that NASA had dubbed the entry, descent, and landing phase of the mission, when the spacecraft slowed from 20,000 km/h to zero, “seven minutes of terror” was not exactly inspiring.

“People who know me will, I’m sure, tell me afterwards, ‘You look nervous,’” said Joe Guinn, Phoenix mission manager, during a press conference the day before landing. “And I am. I’m telling you, I’m getting a real case of the heebie-jeebies now.”

“I’m like Joe, I’m a little nervous on the inside,” Peter Smith, principal investigator for the mission, said at the same press conference. “This is not an easy thing to do. We’ve bet the whole farm on this safe landing, and we can’t do our science without the safe landing. We’ve really worked so hard to build our science instruments, our rationale for why we’re going, our procedures for doing all the science, and yet we have this hurdle to get over before we can do it, and that’s what makes us nervous.”

“I’m telling you, I’m getting a real case of the heebie-jeebies now,” said Joe Guinn, Phoenix mission manager, during a press conference the day before landing.

Barry Goldstein, the project manager for Phoenix, traced that anxiety to the string of events that had to take place precisely for the spacecraft to make it to the surface intact, including the spacecraft’s 12 thrusters and 26 “pyro events” where components separated or deployed. “Each of those can be of very high reliability—99.5 or 99.9 percent—but the problem is that when you have something that has to happen in a very short period of time, all of them have to work and you don’t have another chance, you start stacking those one after the other,” he said. “That’s probably the most nerve-wracking part of this: you stack so many things back-to-back that have to happen successfully, and that’s what drives us to distraction in the last seven minutes.”

Those views were shared by the people working on the mission behind the scenes. “Anxious is a good word to describe my feelings,” said Chris Lewicki, the flight system engineer for Phoenix, in an email interview the week before landing. “Overall I feel the team is well-prepared for landing and the events thereafter, but there’s still a large amount of things that have to go right in order for us start making progress on the surface mission and science.”

Comments like that made outside observers instinctively gird themselves for the worst. After all, if the people working on the mission were talking about “seven minutes of terror” and having “a real case of the heebie-jeebies”, what did that really say about the odds of success?

As it turned out, the state of mind created by those comments only accentuated the thrill when the spacecraft followed the script virtually without deviation and set down on the surface. “It was better than we could have possibly wished for,” Goldstein said in an impromptu press briefing less than an hour after landing. “Everything locked up the way we wanted. Over and over again we rehearsed all the problems and none of them occurred. It went perfectly, just the way we designed it.”

“It went better than any of the tests and simulations that we had run,” said Ed Sedivy, Phoenix program manager for Lockheed Martin, who built the spacecraft. “We did it, and did it with style.”

“This went so perfectly,” Smith said, “it didn’t seem real.”

Second chances

Such elation would be expected for any mission, given the difficulties inherent with safely landing a spacecraft on the surface of another world with our current level of technology and experience. “This is never routine and it’s never going to be routine,” Goldstein said after the landing.

However, the excitement of landing was almost certainly enhanced by the background for the mission. Phoenix got its name because it rose from the ashes of a cancelled mission, the Mars Surveyor 2001 Lander. That mission was terminated in 2000 as part of a restructuring of the overall Mars exploration program in the wake of the failure of Mars Polar Lander, whose design was similar to the 2001 lander. The hardware was put in storage, only to be resurrected as the Phoenix mission, the first of NASA’s Mars Scout program of competitively-selected, relatively low-cost Mars missions.

Phoenix also got lost in the shadows of the spectacularly successful Mars Exploration Rover missions, which continue to operate today more than four years after landing, far beyond their planned 90-day missions. As “just” a static lander, unable to move across the terrain after landing, Phoenix didn’t get the same level of interest and attention as the rovers.

“Phoenix has always seemed to be a bit of an ‘underdog’ mission,” said Lewicki. “Being a stationary three-legged lander, it doesn’t tend to have the allure that Spirit and Opportunity have had. Additionally, we’ve been living in the shadow of the much larger and more ambitions Mars Science Laboratory mission scheduled for launch next year.”

Not being a rover doesn’t bother Smith, who noted the flat terrain devoid of large rocks seen in the first images returned by Phoenix after landing meant that there wouldn’t be much to gain by moving around. “This is exactly what we wanted,” he said. “This is a scientist’s dream.”

“Phoenix has always seemed to be a bit of an ‘underdog’ mission,” said Lewicki. “Being a stationary three-legged lander, it doesn’t tend to have the allure that Spirit and Opportunity have had.”

In an ironic twist, on hand for the landing was Ed Weiler, who was named as the agency’s new associate administrator of the Science Missions Directorate earlier in the month. Weiler has served in a similar position at NASA headquarters in 2000 when the Mars program was restructured. “I had the unique honor to cancel this spacecraft in 2000. You’re looking at the guy who said this spacecraft wasn’t safe to fly,” Weiler said after the landing. “How many times in a career do you get to cancel a mission, Peter Smith comes back to me and says, ‘I’ve got a way to fly this safely,’ you get to reselect it, and you get to be here and see it land. Wow!”

It wasn’t only the lander team who got a second chance. The rover carried a special DVD provided by The Planetary Society called “Visions of Mars” that featured stories, artwork, and greetings. That project had its origins in the early 1990s, and a version of the disc was flown on the Russian Mars 96 spacecraft, which failed to escape Earth orbit and reentered hours after launch. The society eventually found a second chance to fly the disc on Phoenix, keeping the same material flown on the original disc, including a set of Mars-themed artwork by children—or, rather, people who were children in the early 1990s, noted project director Jon Lomberg. “So the kids who did them are now grown-ups, perhaps with children of their own.”

Making it look easy

Phoenix, in many respects, was the exact opposite of the failed Mars Polar Lander mission. The latter suffered from what turned out to be severe underfunding (about $120 million for the mission, excluding launch) as well as, perhaps, a degree of overconfidence given the success of previous missions. Phoenix, by comparison, cost more than twice as much (an official price tag of $420 million including launch), and the project was clearly respectful of the challenges inherent with landing on Mars, up to the point where they may have outwardly appeared less confident about their chances of success than necessary, particularly given how well the landing turned out.

“Experts make it look easy,” NASA administrator Mike Griffin said at the post-landing press conference Sunday night. “Today you had a chance to watch a team in action making something that is incredibly hard to do look easy. And you know they are the most expert of the experts when they can do that.”

The success of Phoenix’s landing, though, does install confidence for the future of Mars exploration, including eventual human missions to the Red Planet. “The way we’re going to land humans on Mars is with propulsive systems and landing legs” and not airbags, Weiler said. “So this is another good step to show that what we did 32 years ago [with Viking] we still know how to do.”

Sedivy added that the solar arrays on Phoenix, provided by ATK, are similar in design to the ones that will be used on NASA’s Orion spacecraft. “So there are a lot of very happy people all over the country to see the solar arrays deployed on Mars.”

“Seven minutes of terror are going to be followed by three months of joy,” said Goldstein.

A lot of the people working on the project, though, are not looking nearly as far ahead, and are just beginning to reflect on their accomplishment. “I sent an email out to the entire team this morning talking about the fact that, aside from the obvious that this is the best team I’ve ever worked with and that they’re all so dedicated, that we’ve done something that has never been done in human history, and that is land north of the arctic circle on Mars,” Goldstein said after a press conference Monday morning.

There were also more mundane issues to deal with. “I haven’t slept in two days,” Goldstein said Monday. “After this press conference I’m going home to get some sleep.”

Now, though, he and the rest of he team had something to look forward to after all the tension of the landing. “Seven minutes of terror are going to be followed by three months of joy.”