The pace for Odyssey's aerobraking at Mars will be brisk. Ultimately, ground controllers will be executing up to 12 drag passes through the atmosphere each day. "Aerobraking is a very judgment-driven sort of thing," says Whetsel. "There's a lot of data that you have to make decisions about. And it's a process that once you've started, you are pretty much committed to seeing it through."

Whetsel compares aerobraking to listening to 'Bolero': "It starts out with these big orbits, and there's a rhythm about when you're going to hit the atmosphere the next time." He drums a desktop to emphasize the beat. "There's a rhythm about all the things you're going to have to get ready for on the next orbit. As the orbit shrinks, the pace picks up and things are happening more rapidly and you either get in the groove or you don't."

On a more comedic note, he says, "It also reminds me of the old classic Lucy Show with the chocolates coming by, and as long as everything's going fine, its going fine, but if you miss one beat, you know you've really gotta scamper to get back into the rhythm as things are going. Because as the orbit shrinks the pace gets faster and faster and faster."

Stick to Your Principles

Matt Landano is the 2001 Mars Odyssey project manager and author of the "Landano Principles" that are guiding JPL's engineering efforts.

As the countdown to Odyssey's arrival at Mars continues, and as new Mars missions for 2003, 2005, 2007 and beyond take shape, the recent difficult past is still foremost in the minds of the design, assembly, test and flight teams. JPL's leadership has put new mechanisms in place to capture and institutionalize the wisdom those painful lessons have imparted.

Says Landano: "You typically learn a lot more from failure than you do from your successes. Mainly because when you have a failure you dig deeply and widely to uncover the root cause of your shortfall."

In 2000, after the loss of the two Surveyor craft, Landano, veteran of the Mars Viking mission and the Voyager, Galileo and Cassini missions to the outer planets, was asked to formally enumerate the engineering principles that have characterized JPL's space engineering triumphs. He also identified the range of acceptable trade-offs and the consequences when engineering principles were skirted. In the process, he says, "I looked at the things on our past Mars failures that got us, and they are not high-technology things," he says.

"In a complex system like a spacecraft, about a million little things have to happen right. The real complex stuff everyone is watching. Areas that are new technology usually have a hundred eyes looking at them." But he points to overlooked fundamentals, including good communication between team members or a hidden flaw in seemingly minor part as examples of dangerous gremlins. "It's the things that you've done many times that you think you know how to do," Landano says. "Somehow, that's the thing that bites you."

"It's a risky business. And if you let your guard down, if you say 'We know how to do this,' you kind of ease up in your mind or in the way you do it. But when you fail, it forces you to take stock again and say, 'Wow, even though I was successful here, look how slim the margin was. I failed here, and I could have failed over here too.' It provides you this heightened awareness for processes, completeness, penetration and applying rigor to everything you do."

Though not yet etched in stone, "Design, Verification, Validation and Operations Principles for Flight Systems," becoming more popularly known in the space community as "The Landano Principles," are now the engineering and management commandments that JPL and its contractors are following to reduce risk and increase the reliability of missions.

At the heart of JPL's risk reduction efforts, says Landano, is a renewed appreciation for margins that must be built into all elements of a project. "Margins enable a project to make design and operational tradeoffs that can significantly reduce mission risks, " he advises. For example, some extra time built into the schedule allows problems to be solved without the panic that comes from an impossible deadline. Some extra mass set aside for the spacecraft may be useful if something needs to be added later in the design and development process. Provisions for additional skilled personnel, if needed, could speed the project over difficult humps if they arise.

"It's all about margin," he says, "especially when you're trying to do it on a tight schedule, when we're trying to do missions in a one-year to 18-month period shorter than we've typically done projects in the past. Because something's got to give somewhere, right?"