Extended Duration Orbiter
NASA program extending Shuttle flights for long-duration microgravity research.
The Extended Duration Orbiter (EDO) program was a NASA project to prepare for long-term microgravity research, initially aimed at Space Station Freedom. It provided practical experience in managing progressively longer spaceflights, as the original Shuttle configuration typically offered only a week to ten days. The most visible hardware component was the EDO-pallet, contracted by Rockwell International.
Quick Facts
- First edo flight overall
- STS-50
- Edo pallet lost on
- STS-107 (2003)
Facts from the source article.
EDO Pallet
The Extended Duration Orbiter Cryogenic kit, also called the EDO-pallet or CRYO, was a 15-foot assembly of equipment that mounted vertically to the rear bulkhead of an orbiter's payload bay. It let the orbiter stay in space for up to 16 days. The kit held cryogenic tanks, control panels, and avionics. While Atlantis received partial upgrades to support the EDO, only Columbia and Endeavour actually carried the pallet on missions. It first flew on STS-50 and was destroyed on STS-107 in 2003. NASA once thought about adding a second EDO pallet to Endeavour, placed ahead of the first, for a total of thirteen tank sets that could have stretched a mission to 28 days. But managers scrapped that idea when work on the International Space Station began, and they removed the EDO capability from Endeavour to cut weight and let it haul more supplies to the station. No replacement was ever planned, because the Station-to-Shuttle Power Transfer System offered similar benefits, and the shuttle fleet's retirement in 2011 made it moot. The EDO tanks held 368 pounds of liquid hydrogen at -418 degrees Fahrenheit and 3,124 pounds of liquid oxygen at -285 degrees Fahrenheit. The system weighed 3,571 pounds empty and about 7,000 pounds (3.2 metric tons) when filled. It supplied extra hydrogen and oxygen to the orbiter's fuel cells, which turned them into electricity. On STS-80, the cells produced 5,856 kilowatt-hours from 3,989 pounds of oxygen and 502 pounds of hydrogen. On STS-50, they made 6,204.7 kilowatt-hours from 4,367 pounds of oxygen and 550 pounds of hydrogen. By contrast, STS-77 without the pallet generated 3,924 kilowatt-hours from 2,745 pounds of oxygen and 346 pounds of hydrogen. The fuel cells also created drinkable water: STS-77 produced 3,091 pounds, while STS-50 and STS-80 yielded 4,914.6 and 4,492 pounds, respectively. Missions with the EDO pallet allowed longer scientific work in microgravity, life sciences, Earth observation, and astronomy, and helped study how humans adapt to low gravity.
EDO medical project
Before the EDO project, no shuttle had flown a mission longer than 10 days. The EDOMP project focused on ensuring that crew could land the orbiter and exit without help after a 16-day flight, addressing orthostatic intolerance and muscle strength reduction. Astronauts on 40 shuttle flights (STS-32 through STS-72) participated in 36 EDOMP investigations. Results were used to make rules and recommendations for 16-day flights. Exercise devices such as a treadmill, cycle ergometer, and rower were developed to prevent de-conditioning. Crew transport vehicles were built to enhance medical capabilities at the landing site. The project produced 125 formal publications and 299 abstracts, technical papers, and presentations, and saw its successor in the ISS Medical Project.
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