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Entering Space

Sixty-four years ago today, the rocket-powered USAF/Bell X-2 aircraft established a new altitude record when the vehicle soared to 126,200 feet above sea level. This historic accomplishment took place on the penultimate mission of the type’s troubled 20-flight aeronautical research program.

The X-2 was the successor to Bell’s X-1A rocket-powered aircraft which had recorded maximum speed and altitude marks of 1,650 mph (Mach 2.44) and 90,440 feet, respectively. The X-2 was designed to fly beyond Mach 3 and above 100,000 feet. The X-2’s primary mission was to investigate aircraft flight control and aerodynamic heating in the triple-sonic flight regime.

The X-2 had a gross take-off weight of 24,910 lbs and was powered by a Curtis-Wright XLR-25 rocket motor which generated 15,000-lbs of thrust. Aircraft empty weight was 12,375 lbs. Like the majority of X-aircraft, the X-2 was air-launched from a mothership. In the X-2’s case, an USAF EB-50D served as the drop aircraft. The X-2 was released from the launch aircraft at 225 mph and 30,000 feet.

The day was Friday, 07 September 1956. The pilot for the X-2 maximum altitude mission was USAF Captain Iven Carl Kincheloe, Jr. Kincheloe was a Korean War veteran and highly accomplished test pilot. He wore a partial pressure suit for survival at extreme altitude.

While the dynamic pressure at the apex of his trajectory was only 19 psf, Kincheloe successfully piloted the X-2 with aerodynamic controls only. The X-2 was not configured with reaction controls. Mach number over the top of the trajectory was supersonic (approximately Mach 1.7).

Kincheloe’s maximum altitude flight in the X-2 (S/N 46-674) would remain the highest altitude achieved by a manned aircraft until August of 1960 when the fabled X-15 would fly just beyond 136,000 feet. However, for his achievement on that late summer day in 1956, the popular press would refer to Iven Kincheloe as the “First of the Space Men”.

Posted in Aerospace, History

Moving Target

Thirty-five years ago this month, the USAF/LTV ASM-135 anti-satellite missile successfully intercepted a target satellite orbiting 300 nautical miles above surface of the Earth. The historic test was the first and only time that an aircraft-launched missile successfully engaged and destroyed an orbiting spacecraft.

The United States began testing anti-satellite missiles in the late 1950′s. These and subsequent vehicles used nuclear warheads to destroy orbiting satellites. A serious disadvantage of this approach was that a nuclear detonation intended to destroy an adversary satellite will likely damage nearby friendly satellites as well.

By the mid 1970′s, the favored anti-satellite (ASAT) approach had changed from nuclear detonation to kinetic kill. This latter approach required the interceptor to directly hit the target. The 15,000-mph closing velocity provided enough kinetic energy to totally destroy the target. Thus, no warhead was required.

The decision to proceed with development and deployment of an American kinetic kill weapon was made by President Jimmy Carter in 1978. Carter’s decision came in the aftermath of the Soviet Union’s successful demonstration of an orbital anti-satellite system.

LTV Aerospace was awarded a contract in 1979 to develop the Air-Launched Miniature Vehicle (ALMV) for the USAF. The resulting anti-satellite missile (ASM) system was designated the ASM-135. The two-stage missile was to be air-launched by a USAF F-15A Eagle executing a zoom climb. In essence, the aircraft acted as the first stage of what was effectively a 3-stage vehicle.

The ASM-135 was 18-feet in length and 20-inches diameter. The 2,600-lb vehicle was launched from the centerline station of the host aircraft. The ASM consisted of a Boeing SRAM first stage and an LTV Altair 3 second stage. The vehicle’s payload was a 30-lb kinetic kill weapon known as the Miniature Homing Vehicle (MHV).

The ASM-135 was first tested in flight on Saturday, 21 January 1984. While successful, the missile did not carry a MHV. On Tuesday, 13 November 1984, a second ASM-135 test took place. Unfortunately, the missile failed when the MHV that it was carrying was aimed at a star that served as a virtual target. Engineers went to work to make the needed fixes.

In August of 1985, a decision was made by President Ronald Reagan to launch the next ASM-135 missile against an orbiting US satellite. The Solwind P78-1 satellite would serve as the target. Congress was subsequently notified by the Executive Branch regarding the intended mission.

The historic satellite takedown mission occurred on Friday, 13 September 1985. USAF F-15A (S/N 77-0084), stationed at Edwards Air Force Base, California and code-named Celestial Eagle, departed nearby Vandenberg Air Force Base carrying the ASM-135 test package. Major Wilbert D. Pearson was at the controls of the Celestial Eagle.

Flying over the Pacific Ocean at Mach 1.22, Pearson executed a 3.8-g pull to achieve a 65-degree inertial pitch angle in a zoom climb. As the aircraft passed through 38,000-feet at Mach 0.93, the ASM-135 was launched at a position 200 miles west of Vandenberg. Both stages fired properly and the MHV intercepted the Solwind P78-1 satellite within 6-inches of the aim point. The 2,000-lb satellite was completely obliterated.

In the aftermath of the stunningly successful takedown of the Solwind P78-1 satellite, USAF was primed to continue testing the ASM-135 and then introduce it into the inventory. Plans called for upwards of 112 ASM-135 rounds to be flown on F-15A aircraft stationed at McChord AFB in Washington state and Langley AFB in Virginia. However, such was not to be.

Even before the vehicle flew, the United States Congress acted to increasingly restrict the ASM-135 effort. A ban on using the ASM-135 against a space target was put into effect in December 1985. Although USAF actually conducted successful additional ASM-135 flight tests against celestial virtual targets in 1986, the death knell for the program had been sounded.

In the final analysis, a combination of US-Soviet treaty concerns, tepid USAF support, and escalating costs killed the ASM-135 anti-satellite effort. The Reagan Administration formally cancelled the program in 1988.

While the ASM-135 effort was relatively short-lived, the technology that it spawned has propagated to similar applications. Indeed, today’s premier exoatmospheric hit-to-kill interceptor, the United States Navy SM-3 Block IA anti-ballistic missile, is a beneficiary of ASM-135 homing guidance, intercept trajectory and kinetic kill weapon technologies.

Posted in Aerospace, History
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