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Glenn Mahone/Bob Jacobs
Headquarters, Washington			Feb. 18, 2003
(Phone: 202/358-1600)

Kim Newton
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256/544-0034

RELEASE: 03-073

INITIAL REQUIREMENTS SET FOR ORBITAL SPACE PLANE SYSTEM

     NASA today released the top level requirements for the Orbital 
Space Plane (OSP), a next generation system of space vehicles designed 
to provide a crew rescue and crew transport capability to and from the 
International Space Station. These requirements set the foundation for 
the design of the vehicle and its associated systems.

The Level I requirements for an OSP system were developed based on 
NASA's missions, as defined in the Integrated Space Transportation 
Plan, input from industry and Department of Defense partners 
participating in the program. The requirements were reviewed at 
multiple levels within NASA. The final review and approval process 
included the NASA Administrator, Deputy Administrator, Associate 
Administrator for the Office of Aerospace Technology, and the 
Associate Administrator, Office of Space Flight. 

"This is an important first step in making the Integrated Space 
Transportation Plan a reality," said NASA Deputy Administrator 
Frederick Gregory. "The Orbital Space Plane system will give us the 
flexibility needed to safely and efficiently get crew to and from 
orbit and to provide crew rescue and logistical support to the 
International Space Station. These initial requirements help to 
outline a comprehensive system that will significantly complement the
capabilities of our existing Space Shuttle fleet," he said.

Any future changes to the Level I Requirements would be considered by 
the Orbital Space Plane Program Office and require approval from the 
NASA Executive Council.

The program is in the process of developing Level II Requirements for 
the OSP system. Unlike the Level I requirements, which were defined by 
NASA, Level II requirements will be defined at the program level and 
will be detailed in a document referred to as the Systems Requirements 
Document (SRD) planned for release no later than late 2003.

The requirements are available on the Internet at:

http://www.nasa.gov/missions/current/MI_FM_osp.html

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Orbital Space Plane Program Level One Requirements

Mission Needs Statement
The vehicle(s) and associated systems will support U.S. International 
Space Station requirements for crew rescue, crew transport, and cargo.

Requirements

1. The system, which may include multiple vehicles, shall provide 
 rescue* capability for no fewer than four ISS crew as soon as 
 practical but no later than 2010.
2. The system shall provide rescue capability that allows the safe 
 return of de-conditioned, ill or injured crewmembers with ongoing 
 treatment until arrival at definitive medical care within 24 hours.
 Crew should not require suits in the vehicle, but the vehicle
 should support crewmembers wearing suits if the situation warrants.
3. The system for rescue shall provide for rapid separation from the 
 ISS under emergency conditions followed by return to Earth.
4. Safety requirements system for crew rescue:
 a. The availability (defined as "a full-up vehicle able to perform 
 its mission") for the escape mission shall be at least:
  Objective:  99%
  Minimum Threshold:  95%.
 b. The risk of loss of crew shall be, with high confidence, lower
 than the Soyuz for the rescue mission.
5. The system shall provide transportation capability for no fewer
 than four crew, to and from the International Space Station, as
 soon as practical, but no later than 2012.
6. Safety requirement ­ system for crew transport:  The risk of loss
 of crew shall be, with high confidence, lower than the Space Shuttle
 for the transport mission.
7. The system shall be designed for minimum life cycle cost.
8. The system shall meet all applicable ISS requirements for visiting 
 and attached vehicles.
9. Compared to the Space Shuttle, the system shall require less time
 to prepare and execute a mission and have increased launch 
 probability.
10. Compared to the Space Shuttle, the system shall have increased
 on-orbit maneuverability.

Operations Concepts

1. The vehicle(s) shall initially launch on an ELV.
2. The system shall be operated through at least 2020.  However,
 the system should be designed so that it could be operated for
 a longer time.
3. NASA envisions that the systems for crew rescue and crew transport
 could be different versions of the same vehicle design.
4. The system shall provide contingency capability for cargo delivery 
 to or from the ISS to support a minimal level of science.
5. The system shall support a nominal ISS crew rotation period of 4-6
 months.
* Rescue includes medical evacuation and emergency evacuation.

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