ahiggins@pequod.cso.uiuc.edu (Andrew Higgins) (03/17/89)
In article <7284@thorin.cs.unc.edu>, symon@lhotse.cs.unc.edu (James Symon) writes: > your numbers suggest to my envelope-back that the benefits of added > speed at launch probably don't warrant the investment in a Mach 5 > launch vehicle. > > So how about Mach 0.0 > at 125,000 ft. under a set of monster balloons? This idea of a "rockoon" has been around for quite a while. It was pioneered by Dr. James Van Allen (forgive me, Henry) in 1952 for cosmic ray research. In 1957, the Air Force fired a series of balloon-suspended rockets into space. Known as Project Farside, the experiments were a pioneering achievement and succeeded in setting an altitude record which remained unbroken even after Sputnik I. The Farside vehicle was lifted to an altitude of 100,000 ft by a large helium-filled polyethylene balloon. The rocket itself consisted of four solid fueled stages (Thiokol Recruits and Arrow II's) with a small (4 X 6 inches) payload package. The six Farside tests were conducted from the remote Eniwetok Atoll (yes, the same as the first megaton H-bomb test) at the Marshall Islands in the Fall of 1957. The balloon-rocket assembly took two hours to rise to the designated altitude. The rockets were spectacularly launched *through* the balloon (the Air Force captured some impressive ground based pictures). Because the rocket was already above 90% of the Earth's atmosphere, the vehicle was allowed to accelerated at a rate which would burn up a similar ground launched vehicle. The total duration of powered flight was around 30 seconds. Unfortunately, the rocket traveled too fast for radar tracking, so altitude was judged by crude optical and radio means. The highest officially recorded altitude was 3,100 miles, although the vehicle could have easily reached 4,000 miles. The payloads on the Farside rockets were alternated between magnetometers and Geiger counters. Had the most successful Farside launch carried a Geiger counter rather than a magnetometer, it very likely would have discovered the Van Allen radiation belts. More elaborate plans were drawn up for Farside II, which would have been able to deliver a payload to the Moon, thus living true to its name. Farside II, however, was not able to compete with the Thor Able Moon rocket, which was chosen for the job in January 1958. Farside II never got farther than the design stage. After the IGY, larger rockets became more accessible, and the ideal of balloon launched rockets slipped out of vogue, with the exception of a single Japanese firing in 1961. The Japanese continue to use balloons to test launch scaled models of the H-II. -- Andrew J. Higgins | Illini Space Development Society 404 1/2 E. White St apt 3 | a chapter of the National Space Society Champaign IL 61820 | at the University of Illinois phone: (217) 359-0056 | P.O. Box 2255 Station A e-mail: ahiggins@pequod.cso.uiuc.edu | Champaign IL 61825 ^^^^^^ "When the Waters were dried an' the earth did appear,...The Lord He created the Engineer" - Rudyard Kipling