| ASM-135 ASAT | |
|---|---|
_missile_during_a_test.jpeg) F-15 Eagle aircraft releasing an anti-satellite (ASAT) missile during a test | |
| Type | Anti-satellite missile |
| Place of origin | United States |
| Service history | |
| In service | Not deployed |
| Production history | |
| Manufacturer | LTV Aerospace |
| Produced | 1984 |
| Specifications | |
| Mass | 2600 lb (1,180 kg) |
| Length | 18 ft (5.48 m) |
| Diameter | 20 in (50.8 cm) |
| Warhead | Kinetic energy kill |
Operational range | 403 miles (648 km) |
| Flight ceiling | 350 miles (563 km) |
| Maximum speed | Mach 12 >13,000ft/s, 8,860 mph (14,260 km/h)[1] |
Guidance system | Infrared homing seeker |
Launch platform | F-15 Eagle |
TheASM-135 ASAT is anair-launchedanti-satellitemultistagemissile that was developed byLing-Temco-Vought's LTV Aerospace division. TheASM-135 was carried exclusively byUnited States Air Force (USAF)F-15 Eaglefighter aircraft. The program was cancelled in 1988.
Starting in the late 1950s, the United States began development of anti-satellite weapons. The first US anti-satellite weapon was theBold Orion Weapon System 199B (also theHigh Virgo missile, Weapon System 199C, attempted to conduct an ASAT test but failed to intercept its target; High Virgo's test was a few weeks before Bold Orion's). Like the ASM-135, the Bold Orion missile was air-launched, but in this case from aB-47 Stratojet. The Bold Orion was tested on 19 October 1959 against theExplorer 6 satellite.[2] The two-stage Bold Orion missile passed within 4 miles (6.4 km) of Explorer 6. From this distance, only a relatively large yield nuclear warhead would likely have destroyed the target.[3]
Starting in 1960 theDepartment of Defense (DoD) started a program called SPIN (SPace INtercept).[2] In 1962, theUS Navy launchedCaleb rockets as part of theSatellite Interceptor Program, with the objective of developing an anti-satellite weapon.[4][5]
The United States developed direct ascent anti-satellite weapons. A modifiedUnited States ArmyNike Zeus missilesuccessfully intercepted an orbiting satellite in May 1963.[6] One missile from this system known as Project MUDFLAP and later asProject 505 was available for launch from 1964 until 1967.[6] A nuclear-armedThor anti-satellite system deployed by the Air Force underProgram 437 eventually replaced the Project 505 Nike Zeus in 1967. TheProgram 437 Thor missile system remained in limited deployment until 1975.[7] One drawback of nuclear-armed anti-satellite weapons was that they could also damage United States reconnaissance satellites. As a result, the United States anti-satellite weapons development efforts were re-directed to develop systems that did not require the use of nuclear weapons.[6]
After theSoviet Union started developing an anti-satellite system, in 1978, U.S. PresidentJimmy Carter directed the USAF to develop and deploy a new anti-satellite system.[8]
In 1978, the USAF started a new program initially designated the Prototype Miniature Air-Launched Segment (PMALS) andAir Force Systems Command's Space Division established a system program office.[8] The USAF issued aRequest for Proposal for the Air-Launched Miniature Vehicle (ALMV). The requirement was for an air-launched missile that could be used against satellites in low Earth orbit.
In 1979, the USAF issued a contract to LTV Aerospace to begin work on the ALMV. The LTV Aerospace design featured a multi-stage missile with aninfraredhomingkinetic energywarhead.[9]
The ASM-135 was designed to be launched from anF-15A in asupersoniczoom climb. The F-15's mission computer andheads-up display were modified to provide steering directions for the pilot.[9]
A modifiedBoeingAGM-69 SRAM missile with aLockheed Propulsion CompanyLPC-415solid propellanttwo pulserocket motor was used as the first stage of the ASM-135 ASAT.[10]
The LTV AerospaceAltair 3 was used as the second stage of the ASM-135.[11] The Altair 3 used theThiokolFW-4S solid propellant rocket engine. The Altair 3 stage was also used as the fourth stage for theScout rocket[11] and had been previously used in both the Bold Orion and Hi-Hoe (Caleb) anti-satellite weapons efforts.[4] The Altair was equipped withhydrazine fueledRCS thrusters that could be used to point the missile towards the target satellite.
LTV Aerospace also provided the third stage for the ASM-135 ASAT. This stage was called Miniature Homing Vehicle (MHV) interceptor. Prior to being deployed the second stage was used to spin the MHV up to approximately 30 revolutions per second and point the MHV towards the target.[12]
AHoneywellring laser gyroscope was used for spin rate determination and to obtain an inertial timing reference before the MHV separated from the second stage.[12] The infrared sensor was developed byHughes Research Laboratories. The sensor used a strip detector where four strips of Indium Bismuth were arranged in a cross and four strips were arranged as logarithmic spirals. As the detector was spun, the infrared target's position could be measured as it crossed the strips in the sensor's field of view. The MHV infrared detector was cooled byliquid helium from adewar installed in place of the F-15's gun ammunition drum and from a smaller dewar located in the second stage of the ASM-135. Cryogenic lines from the second stage were retracted prior to the spin up of the MHV.[12]
The MHV guidance system solely tracked targets in the field of view of the infrared sensor, but did not determine altitude, attitude, or range to the target. Direct Proportional Line of Sight guidance used information from the detector to maneuver and null out any line-of-sight change. ABang-bang control system was used to fire 56 full charge "divert" and lower thrust 8 half charge "end-game" solid rocket motors arranged around the circumference of the MHV. The half charge 8 "end-game" motors were used to perform finer trajectory adjustments just prior to intercepting the target satellite. Four pods at the rear of the MHV contained small attitude control rocket motors. These motors were used to damp off center rotation by the MHV.[12]
On 21 December 1982, an F-15A was used to perform the firstcaptive carry ASM-135 test flight from theAir Force Flight Test Center,Edwards AFB,California in the United States.[8]
On 20 August 1985Ronald Reagan authorized a test against a satellite. The test was delayed to provide notice to theUnited States Congress. The target was theSolwind P78-1, an orbiting solar observatory that was launched on 24 February 1979.[8]
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On 13 September 1985,Wilbert D. "Doug" Pearson, flying the "Celestial Eagle" F-15A 76-0084 launched an ASM-135 ASAT about 320 kilometres (200 mi) west ofVandenberg Air Force Base and destroyed the Solwind P78-1 satellite flying at an altitude of 555 kilometres (345 mi). Prior to the launch, the F-15 — flying at Mach 1.22 — executed a 3.8 g0 (37 m/s2) zoom climb at an angle of 65 degrees. The ASM-135 ASAT was automatically launched at 11,600 metres (38,100 ft) while the F-15 was flying at Mach 0.934 (994.2 km/h; 617.7 mph).[8] The 14 kilograms (30 lb) MHV collided with the 910 kilograms (2,000 lb) Solwind P78-1 satellite at closing velocity of 24,000 kilometres per hour (15,000 mph; 6.7 km/s).[10]
NASA learned of U.S. Air Force plans for the Solwind ASAT test in July 1985. NASA modeled the effects of the test. This model determined that debris produced would still be in orbit in the 1990s. It would force NASA to enhance debris shielding for its planned space station.[13]
Earlier the U.S. Air Force and NASA had worked together to develop a Scout-launched target vehicle for ASAT experiments. NASA advised the U.S. Air Force on how to conduct the ASAT test to avoid producing long-lived debris. However, congressional restrictions on ASAT tests intervened.[13]
In order to complete an ASAT test before an expected Congressional ban took effect (as it did in October 1985), the DoD chose to use the existing Solwind astrophysics satellite as a target.[13]
NASA worked with the DoD to monitor the effects of the tests using two orbital debris telescopes and a reentry radar deployed to Alaska.[13]
NASA assumed the torn metal would be bright. Surprisingly, the Solwind pieces turned out to appear so dark as to be almost undetectable. Only two pieces were seen. NASA Scientists theorized that the unexpected Solwind darkening was due to carbonization of organic compounds in the target satellite; that is, when the kinetic energy of the projectile became heat energy on impact, the plastics inside Solwind vaporized and condensed on the metal pieces as soot.[13]
NASA used U.S. Air Force infrared telescopes to show that the pieces were warm with heat absorbed from the Sun. This added weight to the contention that they were dark with soot and not reflective. The pieces decayed quickly from orbit, implying a large area-to-mass ratio. According to NASA, as of January 1998, 8 of 285 trackable pieces remained in orbit.[13] The last piece of debris, COSPAR 1979-017GX, SATCAT 16564, deorbited 9 May 2004 according toSATCAT.
The Solwind test had three important results:
In the end, the Solwind ASAT test had few consequences for the planned U.S. space station as station completion (indeed, even the launch of first module) was pushed beyond the mid-1990s. The record-high level of solar activity during the 1989–1991 solar maximum heated and expanded the atmosphere more than anticipated in 1985, accelerating Solwind debris decay.[13]
| Flight number | Date | Description |
|---|---|---|
| 1 | 21 January 1984 | Missile successfully tested without miniature vehicle |
| 2 | 13 November 1984 | Missile failed when MHV was directed at a star. |
| 3 | 13 September 1985 | Missile successfully destroys the satelliteP78-1 Solwind |
| 4 | 22 August 1986 | Missile successfully tested when MHV was directed at a star. |
| 5 | 29 September 1986 | Missile successfully tested when MHV was directed at a star. |
Fifteen ASM-135 ASAT missiles were produced and five missiles were flight tested.[10]
The United States Air Force intended to modify 20 F-15A fighters from the318th Fighter Interceptor Squadron based atMcChord Air Force Base inWashington and the48th Fighter-Interceptor Squadron based atLangley Air Force Base inVirginia for the anti-satellite mission. Both squadrons had airframes modified to support the ASM-135 by the time the project was cancelled in 1988.[14]
The USAF had planned to deploy an operational force of 112 ASM-135 missiles.[9]
The deployment of the ASM-135 was central to a policy debate in the United States over the strategic need for an anti-satellite weapon and the potential for anti-satellite weapon arms control with theSoviet Union. Starting in 1983, Congress placed various restrictions on the ASM-135 program,[7] and in December 1985, banned testing the ASM-135 on targets in space. This decision was made only a day after the Air Force sent two target satellites into orbit for its next round of tests,USA 13 and USA 14.[15] The Air Force continued to test the ASAT system in 1986, but stayed within the limits of the ban by not engaging a space-borne target.[16]
In the same year the deployment of the ASM-135 was estimated to cost $US5.3 billion up from the original $US500 million estimate. The USAF scaled back the ASM-135 program by two-thirds in attempt to control costs.[4] The USAF also never strongly supported the program and proposed canceling the program in 1987.[7] In 1988, theReagan Administration canceled the ASM-135 program because of technical problems, testing delays, and significant cost growth.[4]
Related lists
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