19 May 2008
NASA Constellation Program on Track to Return People to Moon
Engineering teams designing complex new spacecraft, rockets simultaneously
Washington -- NASA engineers report progress on the Constellation program, whose Ares I rocket and Orion spacecraft are taking shape to transport human explorers back to the moon by 2020 and then on to Mars and other solar system destinations.
The massive development effort, taking place as NASA races to complete the International Space Station, is unparalleled in the U.S. spaceflight enterprise since the shuttle program formally began in 1972.
The remaining shuttle fleet -- Atlantis, Discovery and Endeavour -- is scheduled to retire in 2010, and Orion’s first manned launch is scheduled for March 2015. In the five-year interval, Russian Soyuz and possibly other spacecraft will transport astronauts and supplies to the International Space Station.
The Constellation program will modify and use both space-shuttle launch pads and the massive vehicle assembly building, but the Ares I and Ares V rockets, a mobile launcher, the Orion spacecraft and the Altair lunar lander are new designs.
“I hope that folks can understand at least some of the complexities of having to design both the rocket and the spacecraft that goes on top at the same time,” Jeff Hanley, manager of the Constellation Program at NASA's Johnson Space Center in Houston, said during a May 15 briefing. “This is a challenge that many missions don’t face, but we’ve made incredible progress.”
BUILDING ORION
Orion will be similar in shape to the Apollo spacecraft but much larger. The Apollo-style heat shield is the best-understood shape for re-entering Earth’s atmosphere, especially when returning directly from the moon.
The spacecraft will be 5 meters in diameter and weigh about 22.7 metric tons. The interior will be more than 2.5 times the volume of Apollo so Orion can accommodate four crew members on missions to the moon and six on missions to the space station or Mars-bound spacecraft.
Orion is scheduled to fly its first missions to the space station by 2015 and make its first flight to the moon by 2020.
“We’re in the midst of preliminary design and that will culminate in a [November 21] preliminary design review,” said Orion Project Manager Mark Geyer, at NASA's Johnson Space Center. “That’s a critical milestone, when we and our customers get together and say that we have the right vehicle and we’re ready to move forward. So it’s essential that we get it right.”
Orion will be able to carry crew and cargo to the space station and rendezvous with a lunar landing module and an Earth departure stage in low-Earth orbit to carry crews to the moon and, one day, to Mars-bound vehicles assembled in low-Earth orbit.
It also will be the Earth re-entry vehicle for lunar and Mars returns. Its shape is borrowed from capsules of the past but takes advantage of 21st-century technology in computers, electronics, life support, propulsion and heat-protection systems.
A launch abort system on top of the Orion capsule will be able to pull the spacecraft and its crew to safety if there is an emergency on the launch pad or at any time during ascent.
For missions to the moon, an Ares V cargo launch vehicle will precede the launch of the crew vehicle, delivering to low-Earth orbit the Earth departure stage and lunar module that will carry explorers on the last part of the journey to the moon’s surface. Orion will dock with the lunar module in Earth orbit, and the Earth departure stage will propel both to the moon.
Once in lunar orbit, the astronauts will use the Altair landing craft to travel to the moon’s surface while the Orion spacecraft stays in orbit. When the astronauts’ mission is complete, they will return to the orbiter using a lunar ascent module. The crew will use the service module main engine to break out of lunar orbit and head back to Earth.
WAITING FOR HUBBLE
Atlantis will be the first spacecraft to be retired as the shuttle program winds down. Its final mission (STS-125), originally scheduled for August 28, will be an 11-day repair mission for seven astronauts to the Hubble Space Telescope. But a new processing schedule for the external tank has added four weeks to five weeks to NASA’s launch manifest, slipping the repair mission to late September or early October. (See “Discovery to Deliver Heart of Japanese Lab to Space Station.”)
This will affect the schedule for the first test of the Ares I rocket, called Ares I-X, scheduled for April 15, 2009. Ares I-X will use one of the shuttle mobile launchers, which will be in use during the Hubble mission.
“The first-blush impact assessment suggests a day-for-day slip,” Hanley said, meaning that the flight test also would slip four weeks to five weeks.
The engineers are looking for work that can be done in parallel to mitigate the effect on the Ares I-X schedule, he added, “but if we can’t come up with anything and it has to be a day-for-day slip, then … that’s perfectly workable. We walked into using shuttle assets for I-X with our eyes wide open that this could happen, so we’re all working together as a team.”
More information about the Constellation Program is available on the NASA Web site.
