About This    Event

About the DC-X

The DC-X (Delta Clipper, Experimental) was the first prototype vehicle developed by the SDIO's (Strategic Defense Initative Organization), now known as the MDA, Missile Defense Agency) SSRT (Single Stage Rocket Technology) reusable launch vehicle program. The SDIO’s interest in SSRT was to support the goal of the 1991 Missile Defense Act, to "deploy an ABM treaty-compliant anti-ballistic missile system that is capable of providing a highly effective defense of the United States against limited attacks of ballistic missiles". In August of 1991, SDIO contracted McDonnell Douglas Aerospace to design and build the DC-X and possible follow-on programs including the DC-Y Orbital Prototype.

Source: https://web.archive.org/web/20021023123411/http://media.armadilloaerospace.com/DCX/

The SSTO program strove to deliver airplane-like operations for rapid turnaround and low per-flight cost. At its heart, the concept involves taking off from Earth, achieving Earth obit and returning to land with the same vehicle. No expendable stages would be required, greatly improving the time to turnaround a vehicle from flight-to-flight, and reducing the cost per flight by not having to replace expended equipment and requiring a radically smaller ground flight control crew and turnaround/maintenance team. Only three people, operating three commercial workstations are required to operate and launch the DC-X. System preparation and maintenance required a team of no more than 25 individuals. Ground testing routinely required only two to three hours to prepare and fire the DC-X. On one occasion the DC-X was actually turned around and fired twice in an eight-hour period, including time to deservice the vehicle, access and reinitialize the systems, alter software limit parameters and reservice the vehicle.

Ground support facilities for the DC-X include the FOCC (Flight Operations Control Center, the mobile 40-foot trailer control center for the DC-X), a launch pedestal, mobile hanger, vehicle transport cart, and a mobile automated propellant servicing system. All critical DC-X support facilities are mobile and transportable. The DC-X can therefore be operated from a variety of dispersed locations without a substantial facility infrastructure. The FOCC itself was designed, developed, fabricated and tested for a total cost of only $1.7 million. At White Sands missile Range, a total of $600,000 of additional permanent facilities were built to support DC-X testing.

Another key point of the SSRT design was to ensure safe abort and return to Earth at any time during launch in case of failure, a capability still lacking in current launch systems. The ultimate goal was to enable safe, low-cost transfer of people and cargo to and from space, dramatically increasing the potential uses of space travel. This non-SDIO spinoff of the technology was referred to as SSTO (Single Stage To Orbit), and was funded by McDonnell Douglas, not SDIO.

The name Delta Clipper comes from two sources. One is the historical impact of the Douglas DC-3 aircraft, known as the Clipper (itself named for the Yankee Clipper ships that opened the sea trade routes more than two centuries before). The DC-3 revolutionized air travel through its high reliability, low operating costs, and sheer high availability. In a matter of years, passenger and cargo air transport became practical and economical to a huge variety of destinations that were unthinkable prior to the DC-3. McDonnell Douglas (now part of Boeing) is the descendent of the original Douglas aircraft company. The Delta part of the DC-X’s name came from the expertise lent by the Thor/Delta rocket program, also from Douglas.

The DC-X was a one-third-size experimental vehicle, built by McDonnell Douglas under a 22-month, $58 million contract. The DC-X prototype’s goals were to verify vertical takeoff and landing, demonstrate subsonic maneuverability, validate airplane-like supportability and maintainability and demonstrate the rapid prototyping development approach. The DC-X suborbital prototype was to be followed by the DC-Y orbital prototype, three times taller, five times heavier (empty) and over twenty-five times heavier fully fueled and loaded. The goal of the orbital Delta Clipper was to put 20,000 pounds of payload into Low Earth orbit (LEO) or 10,000 pounds into polar orbit.

The DC-X and DC-Y designs used Liquid Oxygen (LOX) and Liquid Hydrogen, fueling United Technology/Pratt & Whitney RL10A-5 engines. The RL10A is nearly identical to the engines powering the Centaur upper stage of the Atlas and Titan rockets. It was modified to have a smaller bell, configured for operation at sea level, and gained the ability to throttle between 30% and 100% power. The engine throttling, combined with gimbal mounting, allows for precise attitude control previously unseen in a launch vehicle. The RL10A-5 produces up to 14,560 pounds of thrust and 368 seconds specific impulse in a vacuum. The DC-X utilized four RL10A-5 engines. The DC-X weighed 22,760 pounds dry and empty, and had a gross liftoff weight of 41,630 pounds. The DC-X stands 42-feet tall, and as an experimental prototype has no provisions for any cargo or passengers.

Flight communications systems were provided by Harris Aerospace, Honeywell supplied inertial navigation, Trimble GPS, radar altimeter and flight control computer avionics. Deutsche Aerospace supplied four extendable pneumatic landing gear units, capable of absorbing up to 6.1 meters per second of velocity during emergency landings. Burt Rutan’s Scaled Composites, Inc built the Aeroshell (external body) of the DC-X. 50,000 lines of Ada code were produced with rapid development tools to operate the onboard Vehicle Management System, the brains of the vehicle responsible for monitoring and control of all systems. The FOCC commands the DC-X, but the DC-X itself actually performs all launch, guidance, navigation and landing operations autonomously, safeguarding the vehicle control in case of loss of communications or other situations. The DC-X flies and lands itself.