To The Moon! (In a Minivan)

The Driver's Seat A partial Orion mock-up known as the ROC (reconfigurable operational cockpit) allows astronauts to evaluate the craft's control panel by going through simulations of critical stages of a mission. The ROC has already been used to resolve disputes about window design.

When Orion's engineers tackle a particular design problem, they typically do something called a "trade study," in which they look beyond NASA's workshops, scanning the horizon for new solutions. So, for instance, there are two competing materials for Orion's heat shield, which must protect the capsule and the astronauts upon reentry. The first is the original heat-shield material from Apollo, which is heavy and tedious to apply but can be used in a relatively thin layer. The second, developed in the past decade, is lighter and easier to handle but requires a thicker layer. In a NASA lab in Houston, engineers have spent the past two years evaluating the materials by blasting them in giant furnaces that can create temperatures of up to 5,000 degrees. They expect to make a choice this spring.

In space, Orion will get its power not from heavy fuel cells but from two circular solar panels that will unfurl on either side of the ship in space. The panels are round versions of commercial solar panels used routinely in communication and military satellites. As the performance of solar panels improves, new versions can be swapped onto Orion.

Seats for the astronauts are a surprisingly complicated problem. The seats need to be light and easily stowed once in space. They will be mounted on shock absorbers that allow them to cushion the impact when Orion bumps back to earth. Unlike Apollo, Orion will return to land, not water. Its final touchdown will be absorbed by huge air bags. But in the event that, say, one of the parachutes fails, the seats must help protect the crew. For advice on designing impact-absorbing seats, NASA has turned to NASCAR, of all outfits, which in the last few years has developed technology that restrains race car drivers and helps prevent serious injuries when their cars slam into track walls at high speed.

Every design project--a new Motorola cell phone, a new BMW dashboard, a new Manhattan skyscraper--is a series of trade-offs: between technology and functionality, between ambition and affordability, between the desires of the people creating the object and the needs of the people using it. Spacecraft design is a particularly stark version of those trade-offs because of two unusual challenges--the stakes and the laws of physics. People's lives hang on getting Orion's design right. And the laws of physics impose limits terrestrial designers rarely face. Take the issue of weight. The absolute weight of a spacecraft is set early, by the size of the rocket launching it.

Orion--service module, capsule, escape tower--must weigh no more than 50,250 pounds. The resulting cascade of trade-offs touches almost everything. There is an ongoing wrangle, for example, about whether Orion will have a water heater so astronauts can make coffee each morning--a slim connection to normalcy. Apollo had one, the shuttle has one. Is there room in Orion's "weight envelope" for a water heater? What are you willing to give up to have hot coffee during a 7- to 21-day mission?

Even something as fundamental as windows depends on your perspective. Spacecraft windows have been an issue at NASA since the days of Mercury in the early '60s. Engineers would just as soon create Orion's capsule without windows. That's the strongest, most efficient way to design a spacecraft's structure and skin. The astronauts would prefer a pair of bay windows. That's the way to ensure vital visibility during launch, landing, and orbital maneuvering. Although Orion's flight will typically be automated, astronauts crave a sense of "situational awareness," the ability to orient themselves spatially, physically. That is critical when things start to go wrong. As astronaut Edward Lu told Orion's designers, "I'll trade food for larger windows."

Yet one square foot of spacecraft window--three panes of quartz glass--weighs more than a square foot of metal hull. Every inch of window is weight that has to be shaved somewhere else.

Blaine Brown is the Lockheed engineer in charge of designing the crew capsule. He is so passionate about aeronautical design that he went out and earned a pilot's license--so he'd have a taste of what it's like to fly--and applied to be an astronaut in the class of 2000. Brown's designers delivered an initial Orion capsule with four main windows, two over the control panel, two on either side of it.

Astronauts assigned to consult on Orion's design didn't like the windows. They were, astronaut Lee Morin says, "like looking through a mail slot"--with no view of the horizon and unsatisfactory views for docking. The astronauts originally suggested larger windows that added 80 pounds--to a spacecraft already 5,000 pounds over its limit.