Details have emerged of Orion crew exploration vehicle design reconciliation decisions between NASA and prime contractor Lockheed Martin. The number of parachutes, retro-rocket location, heatshield structure and use of crushable zones have all been agreed between the US space agency and Lockheed, three months after the contractor was selected to develop the vehicle.
During the Phase 1 and 2 competitions for the development contract, NASA developed its own Orion crew and service module designs while the competing Lockheed and Northrop Grumman/Boeing teams worked on theirs.
Since the August downselect, NASA and Lockheed have agreed to have three parachutes, not four to locate the retro-rockets behind the thermal protection system (TPS) heatshield, not in the parachute shrouds as Lockheed had proposed, with the shield being dropped just before landing to allow retro-rocket firing to segment the shield instead of using a monolithic structure and use Lockheed's choice of TPS material, phenolic impregnated carbon ablator (PICA). The Orion capsule will also have a crushable zone on its underside.
"As we drop the heatshield, we can take some area out of the parachutes and that saves weight," said Lockheed's Orion programme manager Cleon Lacefield, speaking at the NASA/American Institute of Aeronautics and Astronautics second space exploration conference in Houston, Texas last week.
Agreement on the design could be completed this week as Lockheed is meeting NASA's Project Orion team following a review of the launch abort system on 7 December. The systems requirements review for the agreed design will take place in the first quarter of next year.