The detailed characteristics and capabilities of the rockets associated with the United States military ballistic missile program are of necessity classified. However, a general assessment of the satellite and space flight capabilities of these developments can be drawn from the information made public in official releases and from the basic principles of rocket flight. Large variations in the performance potentials quoted for a given missile may be expected because of the ability to combine various components in many ways to exploit the capabilities of the launching vehicle.
The Vanguard satellite vehicle is currently the only known development to be completely and originally designed explicitly as a satellite launcher. This system and its flight activities have been quite completely described in the open literature since its inception in the summer of 1955.1 The three rocket-powered stages combine the characteristics of the basic types of rocket powerplant design-turbopump-liquid, pressurized-liquid, and solid propellant-in a single vehicle weighing about 22,000 pounds with an initial thrust of 28,000 pounds. It is designed to place into a satellite orbit some 20 pounds of payload and about 55 pounds of third-stage casing. Many of the fight and ground components and installations originally associated with the Vanguard program have now been combined with other flight vehicles to further the exploration of space.
The Redstone, developed by the Army Ballistic Missile Agency and now in operational status, is a surface-to-surface missile with a range of about 175 nautical miles.2 3 The thrust of the Redstone is about 75,000 pounds,4 indicating a gross weight in the 40,000- to 50,000- pound class. The original propellant combination of liquid oxygen and ethyl alcohol was recently modified to include hydyne as the fuel (replacing the alcohol) and giving an increase of 12 percent in the missile range.5 This improved fuel was used in the successful Explorer I satellite launching on January 31,1958, and all subsequent launchings in the Explorer series. The complete satellite launching rocket used a modified Redstone (lengthened tank section) in combination
1 Fact Sheet: The Vanguard Program, Department of Defense, Office of Public Information, News Release No. 364-58, April 24, 1958.
2 Army Marks 34th Successful Firing of Redstone Ballistic Missile, Department of Public Information, News Release No. 1135-58, November 5, 1958.
3 von Braun, W., Inquiry Into Satellite and Missile Programs, hearings before the Preparedness Investigating Subcommittee of the Committee on Armed Services, United States Senate. 85th Cong. 1st and 2nd sess., pt. I, p. 585.
4 North American Aviation, Rocketdyne division, news release No. NR-6.
5 See footnote 4.
with three upper stages of solid-propellant rockets. The Explorer placed about 31 pounds on orbit with 18 pounds of instrumented payload.6 7
The Thor (Air Force) and Jupiter (Army) IRBM'S are currently in an advanced stage of development. Both missiles are designed for a range of 1,500 miles and have a reported thrust of about 150,000 pounds and a gross weight in the 100,000-pound class.8 The similar capabilities of Thor and the Jupiter to serve as launching vehicles for space flight are being exploited, in the Pioneer Moon rocket program.
The first use was that of the Thor booster combined with the second-stage rocket of the Vanguard to form a two-stage assembly designated "Thor-Able." This vehicle, carrying a test reentry nose cone, traversed a range of about 5 500 miles in July 1958, and is the first ballistic missile known to have achieved this feat.9
The Thor-Able, with a small solid-propellant third stage, is the launching rocket for one type of Pioneer Moon vehicle. A total payload weight of about 85 pounds call be sent on a trajectory to the Moon,10 and somewhat less on an interplanetary trajectory. On the basis of this lunar-shot performance, it can be estimated that the Thor-Able as a satellite launcher could probably place payloads of 300 to 500 pounds in a satellite orbit.
The Thor, combined with a second-stage vehicle developed by Lockheed Aircraft, using a Bell-Hustler liquid-propellant engine, is the first satellite launching vehicle for Project Discoverer. This combination is to place in orbit a total weight of about 1,300 pounds, including the burnout weight of the second stage. The usable payload in orbit is to be some hundreds of pounds, and some payloads are to be physically returned to Earth for recovery.11 12
The Jupiter IRBM has been also combined with an upper-stage assembly (a solid-rocket cluster similar to that used on Redstone-Explorer series) for lunar flights. This launching vehicle, called Juno II, can send a Pioneer payload weighing about 13 pounds to the vicinity of the Moon.13 14 or The Juno II is also to be used to launch Earth satellites, including a 100-foot inflatable sphere.15
With improved upper stages, Thor and Jupiter can launch satellites weighing as much as 2,000 pounds.16
6 Explorer 1, Jet Propulsion Laboratory, California Institute of Technology, External Publication No. 461, February 28, 1958.
7 Gibbs, A. R., Notes on Project Deal, Jet Propulsion Laboratory, California Institute of Technology, External Publication No. 471, March 14, 1958.
8 North American Aviation, Rocketdyne Division, news release No. NR-38
9 Project Able Fact Sheet, Air Force Ballistic Missile Division, news release No. 58-5.
10 Pioneer Instrumentation, Department of Defense, Office of Public Information, news release No. 984-58. October 11, 1958.
11 Department of Defense, minutes of press conference held by Mr. Roy W. Johnson, Director, ARPA, December 3, 1958, 11 a. m.
12 "Project Discoverer" Satellite Program Announced by DOD, Department of Defense Office of Public Information, news release No. 1230-58, December 3, 1958.
13 Juno II Fact Sheet, National Aeronautics and Space Administration, fact sheet No. 3 December 1958.
14 Instrumentation of Pioneer III, National Aeronautics and Space Administration, fact sheet No. 4, December 6, 1958.
15 National Aeronautics and Space Administration, press conference by Dr. T. Keith Glennan and Secretary Donald A. Quarles, December 3, 1958.
16 Johnson, R. W., address before the 13th annual meeting of the American Rocket Society, New York, November 19, 1958; Department of Defense, Office of Public Information, news release No. 1182-58, November 19, 1958.
The approximate cost of a Thor rocket is about $1 million.17
The Atlas and Titan missiles (Air Force) are designed to deliver a thermonuclear warhead to a range of about 5,500 miles.18 The Atlas is currently in flight test, with operational units to be deployed late in 1959.19 The Titan is approaching flight-test status. The gross weight of both missiles is in the 200,000-pound class, with a takeoff thrust in excess of 300,000 pounds. The capabilities of the Atlas and Titan missiles can be exploited to place large weights on a satellite and space-flight trajectory.
The Atlas has the unique capability of being able to, without its military load, place itself, tanks and all, in a satellite orbit at an altitude of 400 miles.20 An Atlas vehicle was placed in satellite orbit on December 18,1958, carrying some 150 pounds of payload at an average orbital altitude on the order of 500 miles.
Unofficial announcements concerning the NASA man-in-space program indicate that the Atlas or Titan can place a payload of about 2,500 pounds into a satellite orbit at an altitude of 150 miles.
If the Atlas is combined with an upper-stage weighing some 20,000 to 30,000 pounds using high-energy propellants, a payload of 6,000 to 8,000 pounds can be placed in a satellite orbit at an altitude of about 400 miles.21 A high-energy upper stage, of unannounced size, for use on Atlas, has been placed in development, and the resulting composite vehicle is expected to be able to launch satellite payloads of 8,000 to 10,000 pounds. 22 23
Developments of rocket engines in the 1.5-million-pound thrust class have been initiated.24 25 A single engine of this approximate thrust combined with a suitable vehicle, could probably place a payload of roughly 30,000 to 50,000 pounds into a satellite orbit at an altitude of 800 miles, and many thousands of pounds on lunar or interplanetary trajectories.
Nuclear rocket development under Project Rover is expected to lead to a very large payload capabilities.26 27
17 Schriever Maj. Gen. B. A., Astronautics and space Exploration, hearings before the select committee on Astronautics and space Exploration, 85th cong., 2d sess., on H. R.11881, p. 670.
18 Schriever, Maj. Gen. B. A., Air Force Ballistic Missile Programs, statement before House Armed Services Committee, 2d sess., 85th cong. Air Force Ballistic Missile Division, news release No. 58-13. February 21, 1958.
19 Atlas Fact Sheet, Convair Astronautics: revised October 24, 1958.
20 Astronautics and space Exploration, hearings before the Select committee on Astronautics and space Exploration, 85th cong., 2d sess., on H. R. 11881, April 15 through May 12, 1958, K. A. Ehricke, p. 633.
21 Astronautics and space Exploration, hearings before the Select committee on Astronautics and space Exploration, 85th conga 2d sess., on H. R. 11881, April 15 through May 12, 1958, K. A. Ehricke, p. 620.
22 see footnote 16 p 141.
23 Design Development contract Let for High-Energy Upper Stage Rocket, Department of Defense, Office of Public Information, news release No. 1134-58, November 6, 1958.
24 see footnotes 11 and 16, p. 141.
25 North American Aviation, Rocketdyne Division, press release No. NR-31.
26 Outer space Propulsion by Nuclear Energy, hearings before Subcommittee of the Joint committee on Atomic Energy, Congress or the United States, 85th cong., 2d sess., January 22, 23, and February 6, 1958.
27 Anderson C. P., Compilation of Materials on Space and Astronautics, No. 2, Special Committee on Space and Astronautics, U. S. Senate, 85th cong., 2d sess., April 14, 1958. see also Congressional Record, January 16, 1958.
For a summary of current and expected payload-weight capabilities, see table 1.
Weight - pounds
|22,000||40,000-50,000||~100,000||~200,000||- - -||- - -|
Thrust - do
300-mile satellite orbit
|22,400-mile (24-hour) stationary||22,000|
Moon impact (circumlunar)
The X-15 manned research vehicle is being developed and tested by North American Aviation under sponsorship of the Air Force, the Navy, and the National Aeronautics and Space Administration. This program had its beginning in research conducted by the then NACA as early as 1952; the go ahead to develop and manufacture the X-15 (three vehicles will be constructed) was given to North American in late 1955. The X-15 is designed to obtain knowledge of flight conditions at extremely high altitudes (approximately 100 miles) and at advanced flight speeds (up to 3,600 miles per hour). The vehicle itself is 50 feet long and weighs more than 31,000 pounds. Some 600 temperature- and 140 pressure-sensing devices will be carried, as well as special equipment to measure structural and aerodynamic loads and pilot reaction. An interesting feature of the X-15 is its two sets of controls: the first, aerodynamic surfaces, will provide control while the vehicle is flying within the mantle of the Earth's atmosphere; and the second, monopropellant rocket thrust units using hydrogen peroxide gas, will enable the pilot to maintain proper flight attitudes in the vacuum conditions outside the sensible atmosphere.
The heating characteristics of the X-15 during exit from and reentry into the atmosphere will be closely measured. Structures which will be subjected to extreme aerodynamic heating have been fabricated from the steel alloy Inconel X; other structures are made from titanium and aluminum.
The vehicle will be powered by the XLR-99 rocket engine, manufactured by the Reaction Motors Division of Thiokol Chemical Corp. This engine uses liquid oxygen and liquid ammonia as propellants and develops a thrust of 50,000 pounds.
Some outstanding features of the X-15 program are (1) extensive research and development in system components, (2) considerable attention to human-factors engineering methods, and (3) hardware production of test vehicles. The X-15 includes provisions for pilot control, so the human occupant will "drive" rather than merely "ride" the vehicle. Flight testing is scheduled to begin in February 1959 at Edwards Air Force Base.28
28 North American Aviation, X-15 Air Vehicle Press Information.
The Dyna-Soar development program was initiated by the Air Force in mid-1958 after about 7 years of preliminary studies and investigations by the Air Force, NACA, and industry. The Dyna-Soar-so named because its flight is based on principles of dynamic soaring-is a rocket-boosted hypersonic glider representing an advanced stage in the development of a manned orbital vehicle for bombing and reconnaissance. The manned vehicle is to be provided with a capability for a certain amount of powered flight and lift for a controlled aircraft landing after reentry.
As with the X-15 research vehicle, attitude stabilization, atmospheric reentry, and human factors will be critical problem areas. The major contractors are Boeing Airplane Co. and an industry team formed by the Glenn L. Martin Co. and the Bell Aircraft Corp.29-33
29 Air Force Announces Development Plans for Dyna-Soar Boost Glide Aircraft, Department of Defense, Office of Public Information, news release, No. 573-58, June 16, 1958.
30 The National Space Program, report of the Select Committee on Astronautics and Space Exploration 85th Cong., 2d sess., p. 7.
31 Glenn L. Martin Co., advertisement, Space/Aeronautics, vol. 30, No. 6, December 1958.
32 The National Space Program, report of the Select Committee on Astronautics and Space Exploration, 85th Cong., 2d sess., p. 24.
33 Putt, Lt. Gen. D. L., Inquiry Into Satellite and Missile Programs, hearings before the Preparedness Investigating Subcommittee of the Committee on Armed Services, U. S. Senate, 85th Cong., 1st and 2d sess., pt. 2, p. 2031.