North American Aviation, Inc., X-15A-1 56-6670 hypersonic research rocketplane on display at the National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)
10 June 1969: The U.S. Air Force donated the first North American Aviation X-15, serial number 56-6670, to the Smithsonian Institution for display at the National Air and Space Museum.
The North American Aviation, Inc., X-15A-1, 56-6670, being brought into the Arts and Industries building, June 1969. The wings and sections of the dorsal and ventral fins have been removed. (Smithsonian Institution Archives SI-A-4145-23-A)
The first of three X-15A hypersonic research rocketplanes built by North American for the Air Force and the National Advisory Committee (NACA, the predecessor of NASA), 56-6670 made the first glide flight and the first and last powered flights of the X-15 Program. It made a total of 82 of the 199 X-15 flights.
Scott Crossfield, North American’s Chief Engineering Test Pilot, made the first unpowered flight 8 June 1959 and the first powered flight, 17 September 1959. NASA Research Test Pilot William H. “Bill” Dana made the final X-15 flight on 24 October 1968.
The first North American Aviation, Inc., X-15A, 56-6670, at the National Air and Space Museum, Washington, D.C. Above and behind the X-15 is the Douglas D558-II Skyrocket that Scott Crossfield flew to Mach 2.005, 20 November 1953. (D. Ramey Logan via Wikipedia)
Scott Crossfield prepares for a flight in the North American Aviation X-15A.
8 June 1959: At Edwards Air Force Base, California, North American Aviation’s Chief Engineering Test Pilot, A. Scott Crossfield, made the first flight of the X-15A hypersonic research rocketplane.
56-6670 was the first of three X-15s built for the U.S. Air Force and NASA. It was airdropped from a Boeing NB-52A Stratofortress, 52-003, at 37,550 feet (11,445 meters) over Rosamond Dry Lake at 08:38:40 a.m, Pacific Daylight Time.
This was an unpowered glide flight to check the flying characteristics and aircraft systems, so there were no propellants or oxidizers aboard, other than hydrogen peroxide which powered the pumps and generators.
The aircraft reached 0.79 Mach (522 miles per hour, 840 kilometers per hour) during the 4 minute, 56.6 second flight.
North American Aviation Chief Engineering Test Pilot Albert Scott Crossfield in the cockpit of an X-15 before a flight. (LIFE Magazine via Jet Pilot Overseas)
In his autobiography, Scott Crossfield described the first flight:
“Three” . . . “Two” . . . “One” . . .
“DROP”
Inside the streamlined pylon, a hydraulic ram disengaged the three heavy shackles from the upper fuselage of the X-15. They were so arranged that all released simultaneously, and if one failed they all failed. The impact of the release was clearly audible in the X-15 cockpit. I heard a loud “kerchunk.”
X-15A 56-6670 under the wing of NB-52A 52-003 at high altitude. Scott Crossfield is in the cockpit of the rocketplane. (Air Force Flight Test Center History Office, U.S. Air Force)
The X-15 hung in its familiar place beneath the pylon for a split second. Then the nose dipped sharply down and to the right more rapidly than I had anticipated. The B-52, so long my constant companion, was gone. The X-15 and I were alone in the air and flying 500 miles an hour. In less than five minutes I would be on the ground. . . .
There was much to do in the first hundred seconds of flight. First I had to get the “feel” of the airplane, to make certain it was trimmed out for landing just as any pilot trims an airplane after take-off or . . . when dwindling fuel shifts the center of gravity. Then I had to pull the nose up, with and without flaps, to feel out the stall characteristics, so that I would know how she might behave at touchdown speeds . . . My altimeter unwound dizzily: from 24,000 to 13,000 feet in less than forty seconds. . . .
X-15A 56-6670 drops from the wing of the B-52 mothership, 8 June 1959. The vapor trail is from venting hydrogen peroxide used to power the aircraft pumps and generators. Note the roll to the right as the X-15 drops away from the Stratofortress. (NASA)
The desert was coming up fast. At 600 feet altitude I flared out. . . .
In the next second without warning the nose of the X-15 pitched up sharply. It was a maneuver that had not been predicted by the computers, an uncharted area which the X-15 was designed to explore. I was frankly caught off guard. Quickly I applied corrective elevator control.
The nose went down sharply. But instead of leveling out, it tucked down. I applied reverse control. The nose came up but much too far. Now the nose was rising and falling like a skiff in a heavy sea. Although I was putting in maximum control I could not subdue the motions. The X-15 was porpoising wildly, sinking toward the desert at 200 miles an hour. I would have to land at the bottom of an oscillation, timed perfectly; otherwise, I knew, I would break the bird. I lowered the flaps and the gear. . . .
. . . With the next dip I had one last chance and flared again to ease the descent. At that moment the rear skids caught on the desert floor and the nose slammed over, cushioned by the nose wheel. The X-15 skidded 5,000 feet across the lake, throwing up an enormous rooster tail of dust. . . .
—Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960, Chapter 37 at Pages 338–342.
This photograph shows the second North American Aviation X-15A, 56-6671, flaring to land on Rogers Dry Lake, Edwards Air Force Base, California. The rear skids are just touching down. The white patches on the aircraft’s belly are frost from residual cryogenic propellants remaining in its tanks after a powered flight. (U.S. Air Force)
Before the drop, it was discovered that the aircraft’s Stability Augmentation System was inoperative in pitch mode. During the flight it was found that the hydraulic-assisted flight control system was responding too slowly to Crossfield’s inputs. Engineers analyzed the problem and increased the hydraulic system pressure. The problem never recurred.
Scott Crossfield was the world’s most experienced rocketplane pilot with 82 rocketplane flights before the X-15 program. “. . . he was intimately involved in the design of the aircraft and contributed immensely to the success of the design.”
—At The Edge Of Space, by Milton O. Thompson, Smithsonian Institution Press, 1992, Introduction, at Page 3.
North American Aviation X-15A 56-6670 made the first glide flight and the first and last powered flights of the X-15 Program. It made a total of 82 of the 199 X-15 flights. 56-6670 is in the collection of National Air and Space Museum at Washington, D.C.
A. Scott Crossfield, wearing a David Clark Co. XMC-2 full-pressure suit, which he helped to design and test, with the first of three North American X-15s, 56-6670. (North American Aviation, Inc.)
Antonov An-225 Mriya with Buran at Paris Air Show, 5 June 1989. (Ralf Manteufel)
5 June 1989: The Antonov An-225 Мрия (Mriya—Dream in the Ukranian language) took off from Kiev with the space shuttle Buran, enroute to the Paris Air Show. The total weight at takeoff was a 1,234,600 pounds (560,005 kilograms)—the greatest weight ever lifted by an aircraft.
The An-225 was derived from the earlier four-engine An-124. It is operated by a flight crew of 6–7. The airplane is 84.00 meters (275.59 feet) long, with a wingspan of 88.40 meters (290.03 feet) and height of 18.10 meters (59.38 feet). The total wing area is 905.0 square meters (9,741.3 square feet).
Mriya weighs approximately 250,000 kilograms (551,156 pounds), empty, and its maximum takeoff weight (MTOW) is 600,000 kilograms (1,322,774 pounds). The maximum payload is 250,000 kilograms (551,156 pounds pounds).
The cargo hold of the An-225 is 43.35 meters (142.22 feet) long, 6.40 meters (21.00 feet) wide and 4.40 meters (14.44 feet) high. The usable volume is 1,300 cubic meters (45,909 cubic feet).
The Antonov An-225 climbing out. (Flightradar24)
The An-225 is powered by six Ivchenko Progress (Lotarev) D-18T turbofan engines producing 229.848 kilonewtons (51,672 pounds of thrust), each. The D-18T is a three-spool axial-flow high-bypass turbofan engine. The 15-stage compressor has a single-stage fan, 7 intermediate-pressure-, and 7 high-pressure stages). The 6-stage turbine consists of 1 high- and 1 intermediate-pressure stages, and 4-stage fan turbine. The engines are 5.400 meters (17.717 feet) long, 2.937 meters (9.636 feet) high and 2.792 meters (9.160 feet) wide. they weigh 4,100 kilograms (9,039 pounds), each.
The transport has cruise speed of 700 kilometers per hour (435 miles per hour) and its maximum speed is 850 kilometers per hour (528 miles per hour). The service ceiling is 11,145 meters (36,565 feet). Mriya carries a maximum fuel load of 300,000 kilograms (661,387 pounds, or 98,567 U.S. gallons, Jet A-1), and has a practical range of 4,500 kilometers (2,796 miles). Its maximum range of 15,400 kilometers (9,569 miles).
four view illustration
The world’s heaviest airplane, Mriya was the only one in existence. It was built specifically to transport Buran. A second An-225 was partially constructed, but never finished.
The An 225 was destroyed during the Battle of Antonov Airport, 24–25 February 2022.
Wreckage of the Antonov An 225 Mriya. (Oleksandr Ratushniak)
Buran, the Soviet space shuttle, made one unmanned flight into orbit, 15 November 1988. It was destroyed 12 May 2002 when its hangar collapsed, killing eight Workers.
4 June 1996: The first Ariane 5 heavy launch vehicle, L501, was launched from the Ensemble de Lancement Ariane 3 (Ariane Launch Area 3) at the Centre Spatial Guyanais (CSG), northwest of Kourou, French Guiana, at 12:33:59 UTC, (9:33:59 a.m., local time).
Everything proceeded normally until T + 00:00:36.7. At that time, the backup Inertial Reference System computer failed. 0.05 seconds later, the primary IRS computer also failed.
Having lost its spatial reference, the guidance system began swiveling the engines to correct a perceived attitude change, which, in fact, had not occurred. This caused the rocket to veer off course.
Once the Ariane 5’s angle of attack reached 20°, at T plus 39 seconds, aerodynamic forces caused a structural failure. The two solid rocket boosters broke away. As the rocket began to break apart, the automatic destruct system was activated. L501 exploded at approximately 4,000 meters (13,123 feet), about 1 kilometer (0.6 miles) from the launch pad. Debris fell, covering an area of approximately 5 × 2.5 kilometers (12.5 square kilometers/4.8 square miles).
Explosion of Ariane 5 L501, 4 June 1996 (ESA)
2.1 CHAIN OF TECHNICAL EVENTS
. . . The internal SRI software exception was caused during execution of a data conversion from 64-bit floating point to 16-bit signed integer value. The floating point number which was converted had a value greater than what could be represented by a 16-bit signed integer. This resulted in an Operand Error. The data conversion instructions (in Ada code) were not protected from causing an Operand Error, although other conversions of comparable variables in the same place in the code were protected. . .
3.2 CAUSE OF THE FAILURE
The failure of the Ariane 501 was caused by the complete loss of guidance and attitude information 37 seconds after start of the main engine ignition sequence (30 seconds after lift- off). This loss of information was due to specification and design errors in the software of the inertial reference system.
The extensive reviews and tests carried out during the Ariane 5 Development Programme did not include adequate analysis and testing of the inertial reference system or of the complete flight control system, which could have detected the potential failure.
—ARIANE 5, Flight 501 Failure, Report of the Inquiry Board, Paris 19 July 1996
When designing the Ariane 5, the same software used in the the Ariane 4 guidance system was used. But the Ariane 5 accelerates in a way that causes horizontal velocity to increase at a rate 5 times that of the Ariane 4. This excessive value could not be processed and the computers shut down.
Gemini IX-A launch from LC-19, 13:39:30 UTC, 3 June 1966. (NASA)
3 June 1966: NASA Astronauts Thomas P. Stafford and Eugene A. Cernan launched from Launch Complex 19, Kennedy Space Center, Cape Canaveral, Florida, at 13:39:33 UTC, aboard Gemini IX-A. The Gemini was a two-man space capsule built by McDonnell Aircraft Corporation of St. Louis. The launch vehicle was a Titan II GLV rocket. Stafford and Cernan were the original Gemini IX back up crew, but the primary crew, Charles Bassett and Elliott See, were killed in an aircraft accident three months earlier.
Thomas P. Stafford and Eugene A. Cernan. (NASA)
The three-day mission was to rendezvous and dock with an Agena Target Docking Adapter in low Earth orbit, and for Gene Cernan to perform several space walks and to test a back pack maneuvering unit.
Gemini IX-A successfully rendezvoused with the ATDA at 17:45 UTC, 3 June. However, the protective shroud had not separated from the Agena and docking with it was not possible.
