Single-stage-to-orbit

SSTO Craft

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Basset Space Center

Biography
SSTO is a launching vehicle capable of achieving orbital trajectory without the use of staging, where the entire vehicle reaches orbit. It uses the term of reusable vehicle as its main development concept. The main challenge, especially for rocket-powered SSTO, is making the vehicle light enough to carry sufficient propellant to achieve orbit, plus a meaningful payload weight. The goals of fully reusable SSTO vehicles are lower operating costs, improved safety, and better reliability than current launch vehicles. The ultimate goal for a SSTO vehicle would be airliner-like operations.

However, the main problem is that an SSTO vehicle does not have much room for weight growth, because every extra pound of vehicle means one less pound for that small payload fraction. Thus a single-stage rocket is at a disadvantage because it must carry its entire vehicle mass to orbit, which in turn reduces payload capacity. On the other hand, a single-stage vehicle doesn't have to carry a second stage, so the vehicle is easier to make lightweight.

In June 1991 General Dynamics, McDonnell-Douglas, Rockwell and Boeing completed SSTO studies and technology demonstrations for the Strategic Defense Initiative Organization (SDIO). Intact abort and rapid turnaround suggest aircraft-type operations, radically different from historical launch vehicle procedures. Mission and payload guidelines included delivery and/or retrieval to Low Earth Orbit in the 10,000 pound range and compatibility with manned flights such as Space Station crew rotation. Rocket propulsion was given as the prime mover since the NASP program is already developing an air-breathing SSTO.

Key SSTO system requirements.

1. Intact abort any time during flight (Save the payload and/or crew)

2. Rapid, low-cost turnaround (Low operating costs using only 350 man-days)

3. Medium payloads deployed and/or retrieved (10,000 lb to low Earth orbit)

4. Manned and/or unmanned operation (Automated flight plus inherent reliability and safety for crews)

5. Rocket propulsion as the prime mover (Avoid dependency on NASP air-breathing technology)

Think unique aircraft operations, not unique space vehicle launches.

If these goals could be achieved, access to space would be much more reliable and affordable. Early in the next century, SSTO might replace Atlas and Delta for medium payloads. Low-cost crew transportation to Spact Station Freedom would be available. Quick reaction deployment of military satellites would be possible in a crisis situation. As SSTO reliability and cost-effectiveness improved, new customers might appear, including commercial users such as global overnight package delivery. This paper describes our recommended SSTO concept: a vertical takeoff and vertical landing ( VTOL) configuration. The focus is on two key technologies: high-performance Aerospike propulsion and Integrated Health Management (IHM). We believe vehicle technology will soon enable SSTO performance, but tumaround in a week with a small crew will require extensive development in automation including I.H. M. This amounts to a change in culture in the launch vehicle business.

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