NASA is halfway through the key portion of its contract with Lockheed Martin, which is building the spacecraft, before it begins tests at the next fall, according to Skip Hatfield, Orion manager at NASA's Johnson Space Center.
"We're making great progress," Hatfield said during a press conference here at NASA Ames Research Center. The conference was organized to provide an update on the progress of NASA's development of the Orion spacecraft, as part of the Constellation Program.
The progress report comes a week aftersaid that it's investigating sabotage of a noncritical computer due to be flown to the International Space Station aboard the space shuttle, which was cleared to lift off on Tuesday. NASA also revealed last week that it allowed inebriated astronauts to fly on at least two occasions despite their posing a flight risk.
Much of NASA's future focus these days seems to be on the Constellation Program, whether on developing the crew vehicle or that can explore uncharted craters on the moon. Once the space shuttle Endeavour is retired in 2010, Orion is slated to be the primary craft for human space exploration, taking astronauts to the ISS by 2015 and onto the moon by no later than 2020. NASA hopes to use the vehicle for other deep space missions onto Mars or an asteroid.
Hatfield said Orion will resemble the Apollo spacecraft that took three astronauts to the moon and back in 1969. Yet Orion will be much larger and capable of carrying six people in its crew capsule to the space station (four to the moon). Orion will be 16.5 feet in diameter and have a mass of about 25 tons. Inside, it will have more than two and a half times the volume of an Apollo capsule. Also, where Apollo's power system used fuel cells, Orion will use solar arrays.
"One of its obvious differences is...in its state of the art avionics system," said Hatfield, who attributed that to advances in computing since the 1960s.
The craft will be comprised of four parts: a launch vehicle, or spacecraft adaptor that will carry the capsule into low-Earth orbit; a service module that contains an engine and pedals for aerodynamics; a crew module (in which the crew rides); and a launch abort system. This system is used to eject the crew in case of emergency on the launch pad. It will also include a set of airbags so the craft can land on solid ground.
One of the more critical elements of Orion that NASA is currently testing is heat shield materials, which are essential to vehicle protection on re-entry to the Earth's atmosphere and have failed in past missions. NASA Ames is developing and testing materials on its own, but it's also contracted with Boeing and Textron Systems to develop alternate heat-shield materials for the spacecraft. It plans to select the best of the lot, said James Reuther, leader of the Advanced Development Thermal Protection Systems Project for Orion at NASA Ames.
Reuther said the team is looking at reusing the heat-shield materials used on Apollo, a proprietary material called Avcoat. But he said the recipe for Avcoat is hard to reproduce without the scientists who initially developed it in the 1960s. Also, Orion will require a stronger material capable of withstanding heat five times stronger than that experienced in re-entry from low-Earth orbit. Given that Orion is larger than Apollo, the heat shield must also withstand a 30 percent temperature increase, he said.
Where does NASA stand on risk of the heat-shield materials for Orion? "We can handle the initial operating system of (re-entry from) low-Earth orbit," Reuther said. "On the lunar side it's a much greater challenge. We need a single heat-shield material for the lunar environment and re-entry...We're at greater risk there building a single system for both from scratch."