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Space Twins Triumphant

Fifty-two years ago this month, NASA’s pioneering spaceflight program, Project Gemini, was brought to a successful conclusion with the 4-day flight of Gemini XII. Remarkably, the mission was the tenth Gemini flight in 20 months.

Boosted to Earth orbit by a two-stage Titan II launch vehicle, Gemini XII Command Pilot James A. Lovell, Jr. and Pilot Edwin E. “Buzz” Aldrin, Jr. lifted-off from Cape Canaveral’s LC-19 at 20:46:33 UTC on Friday, 11 November 1966. The flight was Lovell’s second trip into space and Aldrin’s first.

Like every Gemini mission before it, Gemini XII was not a glitch-free spaceflight. For instance, when the spacecraft’s rendezvous radar began acting oddly, the crew had to resort to sextant and chart to complete the last 65 nautical miles of the rendezvous with their Agena Target Vehicle. But, overcoming this and other obstacles served to provide the experience and instill the confidence needed to meet the truly daunting challenge that lay ahead; landing on the Moon.

Unquestionably, Gemini XII’s single most important contribution to the United States manned space effort was validating the notion that a well-trained astronaut could indeed do useful work in an Extra-Vehicular Activity (EVA) environment. The exhausting and even dangerous EVA experiences of Gene Cernan on Gemini IX and Dick Gordon on Gemini XI brought into sharp focus the daunting challenge of performing even seemingly simple work assignments outside the Gemini spacecraft.

Buzz Aldrin performed a trio of EVA’s on Gemini XII. Two of these involved standing in his seat with the hatch open. The third involved a tethered EVA or space walk. On the latter, Aldrin successfully moved about the exterior of the Gemini-Agena combination without exhausting himself. He also used a special-purpose torque wrench to perform a number of important work tasks. Central to Aldrin’s success was the use of foot restraints and auxiliary tethers to anchor his body while floating in a weightless state.

Where others had struggled and not been able to accomplish mission EVA goals, Buzz Aldrin came off conqueror. One of the chief reasons for his success was effective pre-flight training. A pivotal aspect of this training was to practice EVA tasks underwater as a unique means of simulating the effects of weightlessness. This approach was found to be so useful that it has been used ever since to train American EVA astronauts.

Lovell and Aldrin did many more things during their highly-compressed 4-day spaceflight in November of 1966. Multiple dockings with the Agena, Gemini spacecraft maneuvering, tethered station-keeping exercises, fourteen scientific experiments, and photographing a total eclipse occupied their time aloft.

On Tuesday, 15 November 1966, on their 59th orbit, a tired, but triumphant Gemini XII crew returned to Earth. The associated reentry flight profile was automated; that is, totally controlled by computer. Yet another first and vital accomplishment for Project Gemini. Splashdown was in the West Atlantic at 19:21:04 UTC.

While Gemini would fly no more, both Lovell and Aldrin certainly would. In fact, both men would play prominent roles in several historic flights to the Moon. Jim Lovell flew on Apollo 8 in December 1968 and Apollo 13 in April 1970. And of course, Buzz Aldrin would walk on the Moon at Mare Tranquilitatis in July 1969 as the Lunar Module Pilot for Apollo 11.

Posted in Aerospace, History

X-15A-2: Faster Than a Speeding Bullet

Fifty-one years ago this month, USAF Major William J. “Pete” Knight piloted the fabled USAF/North American X-15A-2 rocket-powered hypersonic flight research aircraft to a record speed of 4,520 mph – roughly a mile and a quarter per second. This mark is approximately 50 percent faster than the highest speed ever attained by a “speeding bullet”.

North American’s original X-15 production run consisted of three (3) aircraft. The X-15A-2 was a rebuild of the 2nd airframe (S/N 56-6671) which had been severely damaged during an emergency landing at Mud Lake, Nevada in November of 1962.

The rebuilt aircraft was configured with a pair of propellant-containing drop tanks that allowed the type’s XLR-99 rocket engine to operate 60 seconds beyond the stock X-15’s 80-second burn time. Among other modifications, the aircraft also carried a pylon-mounted dummy ramjet in the ventral region of the aft fuselage.

With the addition of the external propellant tanks, the X-15A-2 was really a three-stage vehicle. The first stage was the NASA NB-52B mothership which launched the X-15 at Mach 0.82 and 45,000 feet. The second stage consisted of the propellant-laden external tanks which were jettisoned at Mach 2.0 and 70,000 feet. The third stage was the X-15A-2 with its entire internal propellant load.

Due to the increased speed of the X-15A-2, the aircraft was covered with Martin MA-25S ablator to protect it from the higher aerodynamic heating loads. The baseline ablator was pink in color and gave the X-15A-2 a rather odd appearance. Fortunately, application of a white wear/sealer over the ablator gave the aircraft a more dignified look.

On Tuesday, 03 October 1967, Pete Knight and the X-15A-2 dropped away from the NB-52B (S/N 52-008) at the start of the X-15 Program’s 188th mission. Knight ignited the XLR-99 rocket engine and executed a pull-up followed by a pushover to level flight at a little over 102,000 feet. Aircraft speed at XLR-99 burnout was 4,520 mph (Mach 6.7).

As the aircraft decelerated following burnout, Knight executed a series of pre-planned flight maneuvers to acquire vital aerodynamics data. However, passing through Mach 5.5, he received an indication in the cockpit that a high temperature condition existed in the XLR-99 engine bay.

Knight attempted to jettison the aircraft’s remaining propellants, but to no avail. The jettison tubes were welded shut by whatever was happening in the engine bay. This meant he would land heavier and faster than usual. Fortunately, Knight’s piloting skills allowed him to get the X-15A-2 on to Rogers Dry Lake in one piece.

As flight support personnel inspected the X-15A-2 airframe following Knight’s emergency landing, they were alarmed at what they found. The aft ventral region of the aircraft had incurred significant thermal damage. Further, the dummy ramjet was gone.

As reported in the classic NASA document, TM-X-1669, higher-than-expected aerodynamic heating levels were responsible for the damage to the X-15A-2.

First, shock wave/boundary layer interaction heating on the lower fuselage just ahead of the pylon (1) completely destroyed the ablator in that region and (2) penetrated the Inconel-X airframe structure. This introduced very high temperature air into the X-15 engine bay.

Second, impingement of the dummy ramjet nose shock on the detached bow shock coming off of the pylon produced a shear layer that focused on the pylon leading edge. The resulting heating rates were of sufficient magnitude and duration to both burn away the pylon ablator and burn through the pylon structure. The weakened pylon structural attachment eventually failed and the dummy ramjet departed the main airframe.

Pete Knight will forever hold the record for the fastest X-15 flight. However, the X-15A-2 never flew again. Only 11 more flights remained in the X-15 Program at the time. A lack of time and funding meant that little was to be gained by repairing the thermally-damaged aircraft.

As for the final disposition of the X-15A-2 (S/N 56-6671), the aircraft’s remaining ablator was removed with its external surface cleaned-up and original markings restored. The aircraft now resides in a place of honor at the National Museum of the United States Air Force located at Wright-Patterson AFB in Dayton, Ohio.

Posted in Aerospace, History

Wild Ride

Sixty-four years ago this week, the USAF/Douglas X-3 Stiletto experimental flight research aircraft encountered a violent dynamic instability during a flight test maneuver. NACA test pilot Joseph A. Walker was able to successfully recover the aircraft from this flight upset known as Inertial Roll Coupling.

The X-3 was designed to fly at speeds up to Mach 2. The aircraft was approximately 67 feet in length and had a wing span on the order of 23 feet. Aircraft gross take-off weight was 23,840 pounds.

A pair of Westinghouse J46-WE-1 turbojets were intended to power the X-3. However, protracted developmental problems and installation issues with these powerplants would eventually prevent their use in the aircraft.

The X-3 was ultimately outfitted with a pair of Westinghouse J34-WE-17 turbojets. The result was that the X-3 was now grossly underpowered and could barely fly supersonically. Indeed, the Stiletto’s maximum demonstrated Mach number was 1.21 which was achieved in a 30-deg dive!

Notwithstanding the above, the X-3 took to the air 54 times between October 1952 and May 1956 for the purpose of conducting transonic flight research. However, it would be on the type’s 43rd flight that the X-3 would make perhaps its most important contribution to aviation.

On Wednesday, 27 October 1954, Joe Walker took-off in the X-3 (S/N 49-2892) from Edwards Air Force Base, California. At Mach 0.92 and 30,000 feet, Walker applied left aileron at fixed-rudder in an effort to develop a rapid roll response. To Walker’s utter amazement, the X-3 went wild in both pitch and yaw.

Although it seemed to last much longer, Walker was able to recover control of the X-3 within 5 seconds of his initial left aileron input. In true test pilot fashion, Walker again made an abrupt rudder-fixed left aileron input at Mach 1.05. The same thing happened. However, this time the aircraft’s motions were more violent.

Happily, Walker again recovered control of the X-3. Having had enough of flight test frontiersmanship for one day, the intrepid Walker uneventfully recovered the experimental aircraft back at Edwards.

The phenomenon that Joe Walker and the X-3 encountered that day in 1954 is known as Inertial Roll Coupling. It is a resonant divergence in either pitch or yaw due to the presence of roll rate. Aircraft like the X-3, which have low longitudinal and/or directional static stability as well as high pitch-to-roll and yaw-to-roll moment of inertia ratios, are especially susceptible to this phenomenon.

As a postscript to our story, the phenomenon of Inertial Roll Coupling had been hypothesized by the NACA’s William H. Phillips back in June of 1948. For Joe Walker in October of 1954, engineering theory would become flight test fact in a few terrifying seconds high in the skies over Edwards Air Force Base.

Posted in Aerospace, History

The Flight of Sigma Seven

Fifty-six years ago this month, Mercury Astronaut Walter M. Schirra, Jr. orbited the Earth six (6) times in his Mercury spacecraft code-named Sigma 7. The near-perfect 9-hour spaceflight was the United States’ third manned orbital mission flown within a period of eight (8) months.

Project Mercury was United States’ first manned spaceflight program. This historic pioneering space effort helped lay the foundation for America’s quest for the Moon. A total of six (6) missions (2 sub-orbital and 4 orbital) was flown between May of 1961 and May of 1963.

The Mercury Spacecraft measured 11.5 feet in length and had a diameter of 6.2 feet. Orbital weight was roughly 3,000 pounds. With a cockpit volume of only 60 cubic feet, an astronaut’s corporeal fit inside the spacecraft was exceedingly tight. Vehicle entry and egress was a real shoe-horning process. It is not complete hyperbole to say that, once inside, an astronaut wore, more than rode in, the Mercury space vehicle.

Despite its diminutive size, the Mercury Spacecraft was an able space-faring ship. Indeed, it was configured with a complete suite of life support, navigation, attitude control, communications, deboost, recovery and thermal protection systems. Aided by a vast national mission support team, recovery force, and world-wide tracking system, the Mercury spaceflight effort was entirely successful in establishing America in space.

America’s first astronauts were known as the Mercury Seven. History records their names; Shepard, Grissom, Glenn, Carpenter, Schirra, Cooper and Slayton. In the tense 1960’s Space Race with the Soviet Union, these men were indeed America’s Single-Combat Warriors immortalized by the late author Tom Wolfe in his classic book, The Right Stuff.

Mercury-Atlas No. 8 (MA-8) was the fifth Mercury mission. Whereas the two (2) previous flights had been three (3) orbit missions, MA-8 was scheduled to orbit the Earth six (6) times. The focus would be on spacecraft operations instead of space science. The intent was to verify that the Mercury spacecraft could be cleared for an orbital mission duration of at least 24 hours on the very next flight

As was the custom for a Mercury astronaut, Schirra personally named his orbital steed. As such, Schirra chose the name Sigma 7. The term Sigma, the Greek mathematical symbol for summation, signified a summation or culmination of flight experience and engineering development that led to a mature Mercury Spacecraft system. The numeral 7 represented the Mercury Seven.

The MA-8 mission began with lift-off from Cape Canaveral’s LC-14 at 12:15:12 UTC on Wednesday, 03 October 1962. The Atlas D launch vehicle placed Schirra into a 152.8-nm x 86.9-nm orbit. Once in orbit, Schirra quickly got down to business. This included tracking the Atlas booster, maneuvering the spacecraft, observing and photographing the Earth, and conducting various scientific experiments.

Schirra did a particularly good job at conserving the precious supply of Reaction Control System (RCS) fuel. One of the MA-8 objectives had been to do so. In fact, Schirra conserved fuel even more efficiently than planned. Other than an annoying and uncomfortable spacesuit heating problem that occurred several times, the entire MA-8 mission was what Schirra would ultimately call “textbook”.

MA-8 retro-fire occurred at 21:07:12 UTC. During the reentry, the automatic rate stabilization system damped spacecraft pitch and yaw oscillations. Drogue and main parachute deployment took place at 40,000 feet and 15,000 feet, respectively. Splashdown in the Pacific Ocean occurred 1,200 nm northwest of Hawaii at 21:28:22 UTC.

The success of MA-8 paved the way to Gordon Cooper’s historic 22-orbit, 34-hour MA-9 mission in May of 1963. The Gemini and Apollo Programs would soon follow. Wally Schirra would play a big part in both. He commanded the historic Gemini 6 orbital rendezvous mission in December of 1965. Schirra also went on to command the critical Apollo 7 mission in October of 1968.

Wally Schirra was the only member of the Mercury Seven to orbit the Earth in Mercury, Gemini and Apollo spacecraft. He left this earthly scene in May 2007 at the age of 84.

Posted in Aerospace, History

Triple Sonic Great White Bird

Fifty-three years ago this month, the USAF/North American XB-70A Valkyrie reached three times the speed of sound for the first time. This historic aviation achievement took place on the 18th anniversary of the breaking of the sound barrier by the USAF/Bell XS-1.

When it comes to legendary aircraft, aviation enthusiasts speak in almost reverent terms about the XB-70A Valkyrie. Indeed, few aircraft have evoked such utter awe or symbolized better the profound majesty of flight than the “The Great White Bird”. Though its flight history was brief, the XB-70A’s influence on aviation has proven to be of enduring worth.

The Valkyrie measured 185 feet in length, had a wingspan of 105 feet and an empty weight of 210,000 pounds. With a GTOW of 550,000 pounds, it was the heaviest supersonic-capable aircraft of all-time. The aircraft was powered by a six-pack of General Electric YJ93-GE-3 turbojets generating more than 172,000 pounds of thrust in afterburner.

To enhance lift-to-drag ratio and directional stability at high Mach number, the Valkyrie was configured with wing tips that could be deflected downward as much as 65 degrees. Each wing tip was the size of an USAF/Convair B-58A Hustler wing panel. To this day, the XB-70A deflectable wing tip is the largest control surface ever used on an aircraft.

The XB-70A was originally intended to be a supersonic strategic bomber. The aircraft’s mission was to penetrate Soviet airspace at Mach 3 and deliver nuclear ordnance from an altitude of 72,000 feet. However, the rapid ascendancy of Soviet surface-to-air missile capability would compromise the type’s military mission before it even flew.

As a consequence of the above, the Valkyrie ultimately became a high-speed flight research aircraft. Only two (2) copies were constructed and flown. Ship No. 1 (S/N 62-0001) made its maiden flight on Monday, 21 September 1964 while Ship No. 2 (62-0207) first took to the air on Saturday, 17 July 1965.

XB-70A Ship No. 1 became the first Valkyrie to reach Mach 3. It did so while flying at an altitude of 70,000 feet on Thursday, 14 October 1965. The flight crew consisted of North American Aviation test pilot Alvin S. White (aircraft commander) and USAF Colonel Joseph Cotton (co-pilot).

The XB-70A aircraft flew all of their flight research missions out of Edwards Air Force Base in California. Between September of 1964 and February of 1969, a total of 129 XB-70A research flights took places; 83 by Ship No. 1 and 46 by Ship No. 2. A total of nearly 253 flight hours was amassed by the aircraft.

The XB-70A Program made significant contributions to high-speed aircraft technology including aerodynamics, aerodynamic heating, flight controls, structures, materials, and air-breathing propulsion. Lessons-learned from its flight research have been applied to numerous aircraft developments including the B-1A, American SST, Concorde and the TU-144.

XB-70A Ship No. 1 survived the flight test program while Ship No. 2 did not. The latter was destroyed in a mid-air collision with a NASA F-104N on Wednesday, 08 June 1966. Today, XB-70A Ship No. 1 can be seen at the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Dayton, Ohio.

Posted in Aerospace, History

Apollo 7: Return to Flight

Fifty years ago this month, NASA successfully conducted the first manned Apollo Earth-orbital mission with the flight of Apollo 7. This mission was a critically-important milestone along the path to the first manned lunar landing in July 1969.

The launch of Apollo 7 took place from Launch Complex 34 at Cape Canaveral Air Force Station, Florida at 15:02:45 UTC on Friday, 11 October 1968. The flight crew consisted of NASA astronauts Walter M. Schirra, Donn F. Eisele, and R. Walter Cunningham. Their primary goal was to thoroughly qualify the new Apollo Block II Command Module (CM) during 11 days in space.

Apollo 7 was not only the first flight of the Block II CM, but in fact the first manned mission in the Apollo Program. Apollo 7 also featured the first use of the Saturn IB launch vehicle in a manned mission. Apollo 7′s critical nature stemmed from the tragic Apollo 1 fire that took the lives of Virgil I. (Gus) Grissom, Edward H. White II, and Roger B. Chaffee on Friday, 27 January 1967.

The Apollo 1 fire was attributed to numerous deficiencies in the design, construction, and testing of its Block I CM. The Block II spacecraft flown on Apollo 7 was a major redesign of the Apollo Command Module and was in every sense superior to the Block I vehicle. However, it had taken 21 months to return to flight status and the Nation’s goal of a manned lunar landing within the decade of the 1960′s was in serious jeopardy.

The Apollo 7 crew orbited the Earth 163 times at an orbital altitude that varied between 125 and 160 nautical miles. In that time, they rigorously tested every aspect of their Block II CM. This testing included 8 firings of the Service Propulsion System (SPS) while in orbit. Apollo 7 splashdown occurred in the Atlantic Ocean near the Bermuda Islands at 11:11:48 UTC on Tuesday, 22 October 1968.

The Nation’s Lunar Landing Program overwhelmingly got the unqualified success that it desperately needed from the Apollo 7 mission. The Apollo Block II CM would provide yeoman service throughout the time of Apollo. The spacecraft would also go on to see service in the Skylab and Apollo-Soyuz Test Project programs.

While the technical performance of the Apollo 7 crew was unquestionably superb, their interaction with Mission Control at Johnson Spacecraft Center (JSC) in Houston, Texas was quite strained. The crew suffered from head colds through much of the mission and the food quality was poor. Coupled with Houston’s incessant attempts to cram more tasks into each moment of the mission, Apollo 7 Commander Schirra took charge of his ship and made the ultimate decisions as to what work would be performed onboard the spacecraft.

The flight of Apollo 7 would be Wally Schirra’s last mission in space as he had announced prior to launch. As history records, he holds the distinction of being the only astronaut to have flown Mercury, Gemini, and Apollo space missions.

Interestingly, Apollo 7 was not only Schirra’s last time in space, but it was Donn Eisele’s and Walt Cunningham’s first and last space mission as well. That there is a direct connection between this historical fact and the crew’s insubordinate behavior during Apollo 7 is obvious to the inquiring mind.

Posted in Aerospace, History

Final Flight: Bell X-2, Ship 1

Sixty-two years ago today, the No. 1 USAF/Bell X-2 rocket-powered flight research aircraft reached a record speed of 2,094 mph with USAF Captain Milburn G. “Mel” Apt at the controls. However, triumph quickly turned to tragedy when the aircraft departed controlled flight, crashed to destruction, and Apt perished.

Mel Apt’s historic achievement came about because of the Air Force’s desire to have the X-2 reach Mach 3 before turning it over to the National Advisory Committee For Aeronautics (NACA) for further flight research testing. Just 20 days prior to Apt’s flight in the X-2, USAF Captain Iven C. Kincheloe, Jr. had flown the aircraft to a record altitude of 126,200 feet.

On Thursday, 27 September 1956, Apt and the X-2 (Ship No. 1, S/N 46-674) dropped away from the USAF B-50 mothership at 30,000 feet and 225 mph. Despite the fact that Mel Apt had never flown an X-aircraft, he executed the flight profile exactly as briefed. In addition, the X-2′s twin-chamber XLR-25 rocket motor burned propellant 12.5 seconds longer than planned. Both of these factors contributed to the aircraft attaining a speed in excess of 2,000 mph.

Apt and his aerial steed hit a peak Mach number of 3.2 at an altitude of 65,000 feet. Based on previous flight tests as well as flight simulator sessions, Apt knew that the X-2 had to slow to roughly Mach 2.4 before turning the aircraft back to Edwards. This was due to degraded directional stability, control reversal, and aerodynamic coupling issues that adversely affected the X-2 at higher Mach numbers.

However, Mel Apt was now faced with a difficult decision. If he waited for the X-2 to slow to Mach 2.4 before initiating a turn back to Edwards Air Force Base, he quite likely would not have enough energy and therefore range to reach Rogers Dry Lake. On the other hand, if he decided to initiate the turn back to Edwards at high Mach number, he risked having the X-2 depart controlled flight. Flying in a coffin corner of the X-2’s flight envelope, Apt opted for the latter.

As Apt increased the aircraft’s angle-of-attack, the X-2 departed controlled flight and subjected him to a brutal pounding. Aircraft lateral acceleration varied between +6 and -6 g’s. The battered pilot ultimately found himself in a subsonic, inverted spin at 40,000 feet. At this point, Apt effected pyrotechnic separation of the X-2′s forebody which contained the cockpit and a drogue parachute.

X-2 forebody separation was clean and the drogue parachute deployed properly. However, Apt still needed to bail out of the descending unit and deploy his personal parachute to complete the emergency egress process. However, such was not to be. Mel Apt ran out of time, altitude, and luck. The young pilot lost his life when the X-2 forebody from which he was trying to escape impacted the ground at a speed of one hundred and twenty miles an hour.

Mel Apt’s flight to Mach 3.2 established a record that stood until the X-15 exceeded that mark in August 1960. However, the price for doing so was very high. The USAF lost a brave test pilot and the lone remaining X-2 on that fateful day in September 1956. The mishap also ended the USAF X-2 Program. NACA never did conduct flight research with the X-2.

However, for a few terrifying moments, Mel Apt was the fastest man alive.

Posted in Aerospace, Final Flight, History

F-107A First Flight

Sixty-two years ago this month, the USAF/North American F-107A aircraft flew for the first time. The Mach 2-capable fighter-bomber went supersonic on the type’s maiden flight.

The F-107A was designed, developed and tested by North American Aviation (NAA) in the mid-1950’s. With it, the contractor hoped to satisfy Tactical Air Command’s (TAC) need for a front line fighter-bomber. However, Republic Aircraft also had a candidate for the same role; the F-105 Thunder Chief.

The competition between Republic and North American for the TAC fighter-bomber production contract has a story of its own. Suffice it to say here that the competitive effort was (1) extremely close and (2) tinged with political intrigue. In the end, Republic Aircraft reaped the spoils of victory.

Although the F-107A came out on the short end of the stick in the TAC fighter-bomber competition, such did not imply an inferiority in fulfilling the intended role. Indeed, like the Northtrop YF-23’s loss to the General Dynamics YF-22 in the ATF competition of the early 1990’s, North American’s failure to get the nod with the F-107A is still a subject of passionate debate.

The F-107A measured 60.8 feet in length and had a wing span of 36.6 feet. Gross take-off weight was around 41,000 pounds. The aircraft was powered by a single Pratt and Whitney YJ75-P-11 turbojet that produced 15,500 pounds of thrust in military power and 23,500 pounds of thrust in full afterburner.

F-107A longitudinal control was provided by an all-flying horizontal tail. Similarly, an all-flying vertical tail was employed for directional control. Lateral control was provided by a unique 3-segment spoiler-deflector system mounted on each wing. The aircraft was also configured with inboard flaps and leading edge slats for lift augmentation at low speeds.

A unique and prominent feature of the F-107A was its dorsal-mounted air induction system known as the Variable-Area Inlet Duct (VAID). Internally, this unit incorporated a system of adjustable ramps to efficiently decelerate and compress freestream prior to entering the engine compressor face. Ramp deflection scheduling with Mach number was controlled automatically. Ramp boundary layer bleed air was vented from the top of the VAID.

The F-107A carried weapons externally. In addition to wing pylon-mounted stores, the aircraft was designed to carry a single “special weapon” from a semi-submerged recess located on the aircraft ventral centerline. The term “special weapon” means that it was a tactical nuclear bomb. The Sandia-developed store could also be used in combination with a special saddle fuel tank to extend the aircraft’s combat range.

A total of three (3) F-107A aircraft were built and flown. USAF-assigned tail numbers include 55-5118, 55-5119 and 55-5120. On Monday, 10 September 1956, the No. 1 ship (55-5118) took-off from Edwards Air Force Base on its first flight. NAA Chief Test Pilot Robert Baker, Jr. was at the controls. The aircraft attained a maximum Mach number of 1.03 in a 43 minute flight test.

The F-107A could really scream. The type had a maximum climb rate of around 40,000 feet per minute in full afterburner. The maximum demonstrated Mach number attained by the F-107A was Mach 2.18. Program engineers estimated that by increasing the engine inlet area slightly, the F-107A was capable of reaching approximately Mach 2.4.

The trio of F-107A aircraft flew 272 flight tests that totaled 176.5 hours. Included in this testing was successful separation of a special store prototype at Mach 2. Test pilots of note who flew the F-107A included XB-70A pilot Al White and X-15 pilots Scott Crossfield, Bob White, Jack McKay and Forrest Peterson.

Though it never became a production aircraft, the F-107A contributed in significant ways to aviation progress. Indeed, many future aircraft would greatly benefit from F-107A flight control and air induction technology including the A-5 Vigilante, XB-70A, A-12, SR-71, YF-12A and F-15.

The F-107A was the last of NAA’s fighter aircraft which includes such notables as the P-51 Mustang, the F-86 Sabre and the F-100 Super Sabre. While the F-107A has often been referred to in print as the Ultra Sabre, Ultimate Sabre, Super Super Sabre or such, it was never officially assigned a nickname. Alas, there was never an XF-107A or YF-107A designation either. North American Aviation’s TAC fighter-bomber candidate was simply known as the F-107A.

Today, the No. 1 F-107A (55-5118) is displayed at the Pima Air and Space Museum (PASM) in Tucson, Arizona. The No. 2 ship (55-5119) resides at the USAF Museum at Wright-Patterson Air Force Base in Dayton, Ohio. The No. 3 airplane (55-5120) no longer exists as it was relegated to the status of a fire fighting prop and was ultimately destroyed in that role sometime in 1961 or 1962.

Posted in Aerospace, History

First Satellite Intercept Mission

Thirty-three years ago today, 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

The First Spaceman

Sixty-two years ago to the day, 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).

Kicheloe’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
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