Developing the Orion multi-purpose crew vehicle will generate some smoke and fire fairly soon, even as the work is deliberately slowed to avoid the “unsustainable” cost growth that scuttled 's plans to use it to send astronauts to an outpost on the Moon.
One of the few surviving elements of's Constellation program of human exploration spacecraft, Orion is now recast as a multi-destination deep-space crew vehicle with an asteroid tentatively tapped as its first target. The U.S. space agency already has spent more than $5 billion on the capsule, and is on track to run its first orbital flight test early in 2014.
If all goes as planned, a Delta IV heavy rocket will send a high-fidelity test article on a two-orbit mission designed to simulate loads the capsule will encounter returning from the Moon or points beyond, and to exercise techniques for recovering it at sea. That first “Exploration Flight Test” (EFT-1) will be followed by an ascent-abort test similar to the Little Joe tests of the Mercury and Apollo capsules.
“We don't have the money every year to do every system,” says Mark Geyer, NASA's Orion program manager. “So EFT-1 is a great example. We decided to focus our money on the high-risk things, TPS [thermal protection system], crew module structure, parachutes, entry, navigation and guidance. So that's where we're putting our money in '11 and '12.”
Left for a later date will be detailed development of the service module that will fly behind the capsule until shortly before reentry, a task that may see the European Space Agency getting involved (see p. 42). Also on hold are the life-support systems for the crew who will spend up to three weeks in the capsule's cramped interior on early missions beyond low Earth orbit.
The nation's economic and political circumstances have left NASA facing at best a flat budget as of now, forcing the agency to “meter” development of Orion and the heavy-lift Space Launch System intended to carry it deeper into space than the space shuttle ever went (AW&ST Oct. 24, 2011, p. 40). But with $1.2 billion available in the fiscal year that ends Sept. 30, there is plenty of work going on.
Technicians at the Michoud Assembly Facility in New Orleans are putting the finishing touches on the second test capsule. This spring it will be shipped to the recycled Apollo-era Operations & Checkout Facility at, where prime contractor will outfit it with subsystems for flight. Next fall, it will be powered up for the first time.
Meanwhile, the first test article is undergoing ground tests at Lockheed Martin's spacecraft facilities near Denver. It is destined for drop tests into water with a flight-version heat shield at a specializedfacility to gauge how well it handles impacts at different speeds and angles.
Depending on the trials' outcome, that capsule may be refurbished and reused in follow-on flight testing. The same could hold for the EFT-1 capsule as the program seeks ways to stretch funding, depending on the vehicle's condition after it returns to Earth.
“In the big picture, the intent is to reuse as much of the spacecraft as possible; always the goal of design considerations,” says Lawrence A. Price, Orion deputy program manager at Lockheed Martin. “But as we learn more about it and run through tests, some tests [could involve] ultimate conditions where we could permanently deform the vehicle.”
The program has access to a surplus Peacekeeper ICBM stage to use in its ascent abort test, which will validate the ability of the Orion's solid-fuel Launch Abort System (LAS) tower to pull the capsule off a failing launch vehicle and return it to the ground by parachute. Even though it will take longer to acquire and prepare a Delta IV heavy for the EFT-1 mission, NASA and its Orion prime contractor have decided to fly that one first.
“If we fly the orbital test first, we get more information,” Price says. “There are more maturation items that we learn about during that test. And the other thing is that the environments are less rigorous during the orbital test, so it is more likely that the article could survive and be reused from an orbital test.”
EFT-1 will carry aloft the flight-version capsule now at Michoud. Between the launch vehicle's upper stage and the capsule's heat shield will be a dummy service module equipped with test fairings. This will be dropped after the first stage is jettisoned to shed the mass needed for structural reasons at liftoff. That part of the flight will validate the shared load path to ensure the fairing design is stiff enough to help support the crew module and LAS during the highest load condition, Price says.
The Delta IV Heavy will put the vehicle into a 100 X 500-nm initial orbit, and on the second orbit its upper stage will raise the apogee to 3,000-5,000 nm, with the perigee dipping back into the atmosphere. The upper stage and service module will separate, and the capsule will plunge into the atmosphere at something like 84% of a lunar-return velocity. The Avcoat ablative heat shield will protect the capsule as it plunges through the upper atmosphere at more than 20,000 mph, using its reaction control system, slightly asymmetrical heat-shield shape and off-center center of gravity to steer as it slows to the point that its parachutes begin opening.
“We can turn the lift vector so we can fly down range or get a little bit of cross range to get to the landing point,” says Price, adding that the technique—also used on Apollo and planned for the Mars Science Laboratory next summer—can get the capsule to “within just a few miles” of the target for parachute deploy.
“Really all of the error in the landing point is due to drifting under the parachutes with the winds,” he says.
Validating the chute deployment between 40,000 ft. and 20,000 ft. will be a key goal of EFT-1, and preliminary drop tests from aare under way at the Army's Yuma Proving Grounds in Arizona. After the parachute cover is separated from the top of the capsule at the end of the orbital test, a series of drogue, pilot and three main chutes will slow the crew from reentry velocity to “something like 20 mph,” Price says.
The simulated return from deep space reflects NASA's new emphasis on using Orion to carry crews beyond low Earth orbit, with its original role as the first post-shuttle route to the International Space Station (ISS) shifted to private-sector crew vehicles. While it still will be able to carry out that mission as a backup in case there are problems with the commercial crew approach, the reconstituted program will focus on deep space.
So far, that hasn't required much of a change in the plans originally drafted for the Constellation version of Orion, according to Price, who says vehicle requirements for both missions are “mostly identical.”
“A lot of the structure is designed to be able to get out of low Earth orbit and return,” he says. “Micrometeoroid debris shielding is a little different, and radiation is a little different, but when the program began we were kitting those differences, so we could have a vehicle that was optimized for each, and if there were some pieces that weren't common, you could carry a kit that would accommodate that requirement.”
Even before Constellation was canceled, NASA reduced the Orion crew size to four from six for the station mission to save money on adapting the vehicle for four-person deep-space flights. And Lockheed Martin designed distinctive circular solar arrays from the beginning for deep-space flights that will require the vehicle to function much longer than its look-alike predecessor, the Apollo command module.
“Apollo had fuel cells, and we went to solar arrays because it's easier to manage a solar array,” Price says. “You don't need to keep it running all the time, and we wanted to be quiescent for long periods, whether we're sitting at space station, originally, or sitting in low orbit over the Moon or someplace.”
The capsule was designed to sustain a crew for 21 days on its own, and to be able to survive for 210 days on orbit in a quiescent state. Those requirements drove the size of the environmental control and life-support system (ECLSS) needed to keep a crew alive, and the techniques for using the interior layout to shield them against radiation. Beyond that, a habitation module or other spacecraft would be required, depending on the mission.
“If we were going to go do missions that were a year long, you wouldn't want to stay in a small capsule anyway,” says Price. “You'd want to use it for up and down and have it with you if there was an emergency.”
Since a human flight with Orion is not planned until 2021, ECLSS work under prime contractor Hamilton Sundstrand and subcontractor Paragon Space Development Corp. has been slowed. The basic concept uses bottled oxygen and an amine swing bed to remove carbon dioxide and water vapor from the cabin atmosphere.
Current plans call for completing work on the capsule development next year, and then moving on to the other components that will be needed for the early flight tests. That includes the service module, which will carry radiators under the fairings for thermal control; a main engine derived from the 6,000-lb.-thrust space shuttle orbital maneuvering system engine; and tanks for the bipropellant fuel that will power the main engine and the four reaction control systems thrusters.
“[The four engines] are large enough that they could be used as backups to the orbital adjust engine,” says Price.
Phasing work on the service module should prove effective because the more complex systems tend to be housed in the capsule itself and thus will be flight-tested first in EFT-1. The service module subsystems are “more straightforward” and can be left for later, Price says. They are also heavier, which helps with the capsule weight.
“What we've done is move as much as possible out of the crew module into the service module to lighten up [the former] as much as possible,” says Price. “So the whole vehicle is designed to be as light and efficient as it can and [in] the breakdown between the two, the lighter you can make the crew module, the smaller the parachutes are because they don't have to decelerate as much mass, and the smaller the heat shield can be because it's not decelerating as high as mass. The smaller and lighter those pieces are, the less mass you have to take to Mars and back.”
As was the case when Orion won the Constellation competition for a crew exploration vehicle that could take humans to Mars, the latest variant will have a number of interim destinations before striking out for the red planet at some undefined future date. Possibilities range from a repurposed ISS module positioned in a halo orbit around one of the Earth-Moon Lagrange points, to an asteroid, to one of the Martian moons (see p. 44). The exact sequence remains dependent on the funding available for launchers, habitats, landers and other spacecraft that will be used to accomplish the missions.
NASA Program Manager Geyer says the push to hold down development costs goes beyond phasing the work to fit the funding profile, and includes attempts by NASA to mimic private-sector management practices.
“We're trying to increase our efficiency in oversight,” he says. “[We're also] really trying to reduce the reporting products . . . . There's a lot of stuff that drives costs for taxpayers that derives from financial reporting—values, [work breakdown structure] levels, institutional requirements and how stuff is reported. It can be a very large overhead, so we are working with headquarters on streamlining that and reducing the number of unique formats and reports that are generated that frankly, in my mind, don't necessarily really help us manage the program.”
Not surprisingly, the Orion program has met with some resistance to its cost-cutting efforts inside NASA. “It takes time to convince them as to why there's another way to do this, Geyer says. “It's not some evil intent, some evil brat who just wants to slow things up. [Sincere, dedicated] workers believe their piece is critical, and sometimes people act as if affordability is for the other guy.”