Boeing X-20 Dyna-Soar

Did You Know?

• The 1959 Twilight Zone episode 'And When the Sky Was Opened' referenced an X-20 spacecraft with a crew of three.
• John Berryman's 1963 short story 'The Trouble with Telstar' featured a Dyna-Soar intercepting communications satellites for repair.
• The 1969 film Marooned used a rescue craft modeled after the Dyna-Soar, called the X-RV.

Background

After World War II, German scientists brought to the United States via Operation Paperclip included Walter Dornberger and Krafft Ehricke, who joined Bell Aircraft. In 1952 they proposed the Bomber Missile (BoMi), a vertical-launch rocket vehicle that would use a skip-glide technique to extend its range. This method involved boosting the vehicle to high speed and altitude, then using wing lift to bounce back into space repeatedly until the pilot glided to a landing. Interest in BoMi led to three separate programs by 1956: RoBo (Rocket Bomber), Brass Bell (reconnaissance), and Hywards (a prototype for technology development).

Development

The Dyna-Soar program had three stages: a research vehicle (Dyna-Soar I), a reconnaissance vehicle (Dyna-Soar II), and a strategic bomber (Dyna-Soar III). First glide tests were expected in 1963, with powered flights reaching Mach 18 in 1964. A robotic glide missile was planned for 1968, and the operational weapons system by 1974. In March 1958, nine companies bid for the contract; Boeing was awarded it in June 1959 after its design came to resemble Bell's proposal. The Titan III was chosen as the launch vehicle in late 1961.

Spacecraft description

The X-20 Dyna-Soar had a low-wing delta shape with winglets instead of a conventional tail. Its framework and upper surface panels were made from René 41 super alloy; the bottom used molybdenum sheets over insulated René 41, and the nose cone was graphite with zirconia rods. A single pilot sat in front, with an equipment bay behind that could hold data-collection gear, weapons, reconnaissance equipment, or a four-person mid-deck for the X-20X shuttle version. A Martin Marietta Transtage upper stage at the aft provided orbital maneuvers and launch abort capability, then was jettisoned before descent. An opaque refractory-metal heat shield protected the front window during re-entry and was jettisoned after aerobraking for landing visibility. The craft could change orbital inclination by skimming the atmosphere, a unique ability for rendezvous even with evading satellites. Its tricycle undercarriage used retractable wire-brush skids of René 41, not rubber tires.

Operational history

Seven astronauts were secretly chosen for Dyna-Soar in April 1960: Neil Armstrong, William H. Dana, Henry C. Gordon, Pete Knight, Russell L. Rogers, Milt Thompson, and James W. Wood. Armstrong and Dana left in mid-1962; Albert Crews joined on 19 September 1962, and the six remaining astronauts were publicly announced. By end of 1962, the craft was designated X-20, its drop-test booster had fired successfully, and an unveiling ceremony was held in Las Vegas. Minneapolis-Honeywell completed flight tests of an inertial guidance subsystem on an NF-101B Voodoo at Eglin Air Force Base by August 1963. Boeing B-52C 53-0399 was assigned for air-dropping the X-20, later used for other tests. The program faced two major problems: uncertainty over the booster and lack of a clear goal. Many boosters were proposed, including Atlas-Centaur, Titan I, Titan II, Titan III, and Saturn C-1; the Titan IIIC was chosen in December 1961, but vacillations delayed the project.