In December 2014, a Delta IV Heavy rocket will thunder skywards from Florida, launching NASA’s first Orion spacecraft to an altitude that has not been achieved by a human spacecraft flight since the last Apollo lunar landing mission forty years ago. Designated Exploration Flight Test-1 (EFT-1), this milestone test (to be made without a crew) shows the progress being made by this once troubled spacecraft which could yet be humanity’s first interplanetary vehicle.
At the end of August 2006 NASA formally named its planned new spacecraft, the Crew Exploration Vehicle, and selected a contractor to build the craft. The vehicle was named the Orion. Orion is constructed by aerospace giant Lockheed Martin after a rival bid from a consortium of Northrop-Grumman and Boeing was rejected. Many considered Lockheed-Martin a surprising choice as this corporation has a perceived history of being awarded space vehicle development contracts which fail to deliver a successful final product. For example, in the 1990s Lockheed Martin was contracted to produce the X-33, a spaceplane which was the basis of an earlier project to replace the Space Shuttle. Sadly, the company appeared to have grossly underestimated the difficulty of the project and the craft was never completed. Presumably they have now regained NASA’s confidence after this fiasco and the project appears to progressing relatively smoothly. Lockheed Martin’s major subcontractors on the project are United Space Alliance, Aerojet, ATK, Honeywell and Hamilton Sundstrand; approximately 3000 people work on the Orion program across the USA.
The Orion CEV was originally designed as the workhorse vehicle of NASA’s Project Constellation which had a return to the Moon as its centrepiece. Constellation, an ambitious but underfunded (and thus underachieving) project was cancelled by President Obama in February 2010 and so was the Orion CEV. However Orion dodged this apparently fatal blow when the US Congress mandated that NASA develop a “Multi Purpose Crew Vehicle” capable of travelling beyond low Earth orbit (LEO) into deep space to the Moon, Earth’s Lagrangian Points or even nearby asteroids. NASA essentially continued to develop the MPCV from the Orion capsule.
The Orion MPCV (Multi-Purpose Crew Vehicle) is based on the original Orion design requirements for traveling beyond low Earth orbit (LEO). Orion will serve as an exploration vehicle that will carry crews into space, provide emergency abort capability (in other words carry the crew to safety if the launch vehicle explodes), sustain the crew during the space travel and provide safe re-entry from deep space return velocities. It is to be capable of conducting regular in-space operations (rendezvous, docking, extravehicular activity) in conjunction with additional payloads (booster stages, habitation modules and landing vehicles) delivered into orbit by the Space Launch System (SLS) for missions beyond LEO. It is also to be a backup system for International Space Station cargo and crew delivery if the planned Commercial Orbital Transportation Services fail to materialise.
From the start of the project, the spacecraft’s very conservative basic concept was criticized. It is not a sleek, futuristic spaceplane. Instead each Orion will bear a strong visual resemblance to the historic three-seat Apollo spacecraft, but is to be considerably bigger, being about 5 m (16.5 feet) in diameter, with a mass of about 21 tonnes. In comparison, an Apollo was 3.9 m in diameter and weighed 30 tonnes- the Orion’s internal volume is about 150% more than that of the Apollo capsules. An Orion will be constructed from modern Aluminium-Lithium alloy, helping to make it lighter and tougher than the Apollo capsule, and will utilize the latest electronic and computer technology based on the systems fitted to the advanced Boeing 787 airliner.
The Crew Module provides a safe habitat in deep space for the crew for up to three weeks (longer missions would require addition Service Modules), accomodates consumables and research instruments, and houses a docking port for crew transfers to other vehicles. The Orion is capable of docking automatically with the ISS. Much to the relief of crews who may have to spend days on board, the craft will be fitted with a unisex lavatory permitting a degree of privacy (in the interests of good taste, the hygiene facilities on board Apollo are best left undescribed). An Orion will have an onboard recycling system, identical to that used on the International Space Station, this will convert both waste water and the crew’s urine into water for both drinking and cooling. The crew module is the only part of the MPCV that returns to Earth after each mission.
The Service Module supports the crew module from launch throughout the mission. It provides space propulsion capability for orbital transfer, attitude control, and high altitude ascent aborts. The Orion Main Engine (OME) is a 33.4kNewton (7500 pound) thrust, storable bi-propellant rocket engine made by Aerojet. The OME is an upgraded version of the Space Shuttle Orbiter’s Orbital Maneuvering System (OMS).While attached to the Crew Module, the Service Module provides the water, oxygen and nitrogen needed for a habitable environment, generates (by way of large solar arrays) and stores electrical power and maintains the temperature of the vehicle’s systems and components. This module can also transport unpressurized cargo and scientific payloads.
For at least the first three Orion flights an alternative Service Module will be used. This is supplied by the European Space Agency and it is derived from the highly successfully Automated Transfer Vehicle designed and operated by ESA to service the ISS. It retains the ATV’s characteristic X-shaped solar arrays.
An Orion will be launched on an Space Launch System rocket and carry up to four astronauts to rendezvous in orbit with a booster stage and possibly a habitation module launched earlier by another SLS rocket. After linking up the combined spacecraft could take the astronauts to the Moon’s surface or a near Earth asteroid and back again. Looking further ahead, Orion may play a part in a possible mission to Mars. Returning to Earth, the Orion’s Crew Module will descend on parachute to a landing in the ocean.
NASA estimates that a flight in an Orion will be substantially safer than a Shuttle mission. An Orion’s heatshield will be protected from debris until the vehicle is returning to Earth, and if an accident occurs during the mission’s launch phase, an escape rocket system will carry the craft to safety. This is the Launch Abort System (LAS), designed to activate within milliseconds to propel the crew module to safety. A similar device on the Russian Soyuz spacecraft has saved the lives of the crew on a couple of occasions. The system also comprise an acorn-shaped aerodynamic shroud which protects the Crew Module from dangerous atmospheric loads and heating, then is jettisoned after the ascent to orbit.
The 2014 test flight will take Orion to an altitude of more than 5750 km (3600 miles), more than 15 times farther away from Earth than the International Space Station. Orion will return home at a speed almost 8000km/h (5000mph) faster than any human spacecraft since astronauts returned from the Moon, simulating the kind of return that will be required when astronauts come home from voyages beyond low Earth orbit. The hope is that the first manned Orion flight to Earth orbit will be in 2020. Beyond that milestone, there is currently no plan in place for where Orions will venture, suggestions include missions to establish a space station hovering over the Moon’s farside at Earth’s L2 Lagrangian point, flights to near Earth asteroids or even a series of increasingly ambitious missions cumulating in a Martian expedition in the 2030s.
The Orion MPCV may not be the USS Enterprise but it appears to be a technically sound and workable design which if successfully developed will deliver a safe and reliable vehicle to enable the future exploration of space (if the money is made available, to quote Robert A. Heinlein “Interplanetary travel is waiting at your front door — C.O.D. It’s yours when you pay for it” ).
(Article by Colin Johnston, Science Communicator. The title is borrowed from a novel by that much missed SF author Poul Anderson)