Thinking back to the failed 1999 mission, Smith is amazed at how close to the wire that project was run. “We literally did not have enough time in those days to track down the reason for every anomaly we might have found during testing,” he says. Those were the days of “faster, better, cheaper,” a speed-it-up, keep-it-cheap philosophy espoused by NASA’s then-administrator Dan Goldin. The 1990s saw a dramatic increase in the rate of space science missions, but even Goldin admitted later that he pushed the agency’s workers and contractors too hard. When the low-cost Scout program was proposed, NASA agreed that the scope of the missions would also be scaled back; scientists and engineers wouldn’t be forced to do more with less.
Phoenix originated with a phone call in early 2002. Chris McKay, a planetary scientist at NASA’s Ames Research Center in California, called Smith to say, “Hey, let’s do something with the Surveyor lander.” NASA was inviting ideas for the first Scout, due to fly in 2007, and McKay and some of his colleagues at Ames had already been studying, with NASA money, ways to take the hardware from the canceled mission out of storage. “The word on the street was that headquarters would never let the 2001 lander fly,” McKay recalls. “Not just ‘No’ but ‘Hell no.’ ”
So, as a way to keep costs down, the scientists adapted the unused lander for their Scout proposal, with the idea that they’d use the equipment to do a detailed analysis of some patch of Martian soil. There was one small problem. “We didn’t know where to go,” Smith says. “We’d have a shovel, a bunch of instruments, and a pretty good general-purpose lab. We just didn’t know where to land it.”
Like an answer to a prayer, another NASA mission provided a solution. The Mars Odyssey entered orbit around Mars just as the space agency was getting ready to decide which Scout mission proposals to fund for further study. Measurements of hydrogen by Odyssey’s gamma-ray spectrometer strongly suggested that at both polar regions, shallow ice exists at or near the surface. Planners would select a launch window for the 2007 mission that would enable the craft to land on Mars during northern spring and summer, when the days would be longest. And because it included instruments from the 2001 spacecraft, Phoenix would have more capabilities than the 1999 lander, and be more economical. Smith, in essence, was asking for a second chance at the mission that broke his heart.
In August 2003, NASA selected Phoenix as its inaugural Scout mission. Smith’s proposal beat two dozen others, including one that would have returned samples of the Martian atmosphere to Earth. Mike Meyer, the senior scientist for NASA’s Mars exploration program, is all in favor of resurrecting the goals of an approved but never-realized mission: “Mars Polar Lander was built for a very good reason, and Phoenix recaptures many of its advantages,” he says. “It should give us a very good idea what that ice is made of, and also what the seasonality of Mars is and how that fits into long-term orbital cycles and climate change.” That information, combined with remote sensing data from other spacecraft, could help scientists plan future Mars missions by suggesting regions where water is likely to have flowed in the past.
It hasn’t been all smooth sailing since the NASA selection. The space agency has become more cost-conscious than ever, and if a Scout spacecraft can’t be built properly within the approved budget, says Smith, it either gets scrapped or is scaled back to match the available funds. Despite the team’s best efforts, it ran its budget dry. Into the discard heap went a radio transmitter, called the X-band antenna, which would have enabled Phoenix to transmit data directly to Earth. Now the only means of communication will be through the two spacecraft already circling the planet, the Mars Odyssey and the Mars Reconnaissance Orbiter, which will act as relays. The 1999 failures taught NASA one important lesson, however. Phoenix will continue transmitting data and reports on its condition all the way from atmospheric entry to touchdown. If something goes wrong during descent, mission managers will at least know what happened. Losing a spacecraft is bad enough, says Smith; never finding out why “is just horrible.”
Late last year the project team let NASA know it was having money trouble. The biggest headache had been the landing radar, or altimeter. The original unit was inherited from the stored 2001 lander. Adapted from an altimeter used on F-16 fighters, “it was old when they put it in,” Smith says. “The Air Force doesn’t use this one anymore. We couldn’t even get parts, and the guys who knew it best had retired.” Tests revealed its performance was erratic, making data dropouts at critical times possible. The engineers spent months, with Lockheed doing much of the work, making a reliable altimeter.
The project’s budget had included a reserve fund for just these kinds of unexpected problems. Even so, the extra altimeter work, combined with fixes for other glitches and the late scramble to find a safe landing zone, put Phoenix tens of millions of dollars over the $386 million cap NASA had set for the mission. The team had been warned that a cost overrun would set off a formal NASA termination review. One was held in late January. After Phoenix passed, Smith said it had been unlikely all along that NASA would actually cancel a mission so close to launch. But he did tell a Rocky Mountain News reporter that watching the bills run up had kept him in agony for months.
Even with the overrun, if Phoenix continues the Mars program’s current string of successes, NASA will likely consider its money well spent. Since the 1999 loss of the Mars Polar Lander, the news has been all good: Mars Odyssey (launched in 2001 to further the study of Martian geology and weather), the twin rovers, and the Mars Reconnaissance Orbiter (launched in 2005) all arrived safe and sound, and all four are still working. The orbiters are busily mapping the composition of the atmosphere and the surface, as well as using ground-penetrating radar to explore the subsurface. The Mars Express, a European orbiter with a suite of powerful cameras and other sensors, has performed flawlessly. The Spirit and Opportunity rovers have delighted their operators by running well into their third year and traveling a combined total of more than 11 miles.
If Phoenix does find traces of organic materials and conditions suitable for life, or if it just helps scientists understand how water cycles between the ground and the atmosphere, it will shape the scientific questions to be answered by subsequent Mars missions. Favorable launch windows (meaning those that require the least amount of rocket fuel to reach the planet) come around every 26 months, and NASA tries to hit every window. Next up after Phoenix is a long-range rover called the Mars Science Laboratory, which in 2009 will carry an even more advanced organic chemistry lab to extend the search for life. Another Scout mission, still to be selected, is slated for the following opportunity, in 2011. Beyond that, things become uncertain. NASA’s Mars program has gotten leaner in recent years as the agency has shifted money from space science into preparations to send astronauts back to the moon. A Mars sample-return mission, once the program’s highest priority, has been pushed off into an indefinite future.