Forty-nine years ago this week, the highly-classified CIA/Lockheed A-12, with Lockheed Test Pilot Lou Schalk at the controls, took to the air for the first time. The historic flight originated from the U.S. government’s top secret flight test facility at Groom Lake, Nevada.
The high stakes of the Cold War compelled the United States to develop the capability to perform covert surveillance missions via overflight of the Soviet Union. The Central Intelligence Agency (CIA) was tasked by the Eisenhower Administration for the job. The CIA partnered with the Lockheed Company to develop a high-flying reconnaissance aircraft known as the U-2.
Outfitted with a suite of high tech cameras and sensors, the U-2 was flown by CIA pilots from 1956 through 1960 to gather vital intelligence data regarding Soviet military capabilities. The aircraft penetrated Soviet territory at altitudes in excess of 70,000 feet and a top speed of about 500 mph. The type’s unrefueled range was more than 5,500 nautical miles. Maximum endurance was 12 hours.
Soon after the U-2 began flying operational missions over the Soviet Union, the U-2 was detected on Soviet radar. Fortunately, Soviet ground-launched missiles were unable to reach the high-flying surveillance aircraft. But the writing was on the wall. It would be only a matter of time before the Soviets improved their defenses to the point that the U-2 would be intercepted. That day occurred on Sunday, 01 May 1960 when a U-2 flown by the CIA’s Francis Gary Powers was brought down over Russia by a Soviet SA-2 missile.
Three years prior to the U-2 incident, the CIA-Lockheed team had begun classified development of the next generation surveillance aircraft. The new aircraft was designed to enter denied airspace at altitudes beyond 85,000 feet and speeds in excess of 2,000 mph (Mach 3+). The camera and sensor systems payload would be a vastly improved over that of the U-2 as well. The idea was to fly when and where required as national security needs dictated.
The CIA’s new supersonic surveillance aircraft was known simply as the A-12. The “A” designation was shorthand for the name Archangel within the Lockheed Advanced Development Projects (The Skunk Works) organization in Burbank, California. The “12” represented the 12th and final iteration of the Archangel airframe design series. In January of 1960, the CIA contracted with Lockheed to produce a dozen A-12’s at the latter’s Burbank facility under the code-name of Project OXCART.
Groom Lake airfield, situated on the USAF’s Area 51 military installation in southern Nevada, was selected as the location for A-12 flight test. The remote and then-publicly-unknown test site was chosen to provide maximum protection from prying eyes and thus help maintain the covert nature of the A-12’s development.
The No. 1 A-12 (S/N 60-6924) was scheduled for what was to be a high-speed taxi test on Saturday, 26 April 1962. The official test plan called for Lockheed Chief Test Pilot Louis W. “Lou” Schalk to get the aircraft up to something just below the minimum rotation velocity of the airplane. However, the A-12’s chief architect, the inimitable Kelly Johnson, privately instructed Schalk to fly the aircraft off the runway and then quickly set it back down. Johnson wanted Schalk to experience how the aircraft felt during take-off in preparation for the upcoming official first flight.
Schalk did as he was instructed. However, as the aircraft took to the air, the pilot found it to be unstable in all three axes. After a pulse-elevating struggle with his shaky stead, Schalk managed to get the A-12 back on the ground in one piece. However, his wild nap-of-the-earth flight profile had consumed 8,000 feet of concrete runway and an additional mile or more of dry lakebed. All that on-lookers could see was a big dust cloud!
Fearing the worst, Groom tower attempted to contact Schalk to ascertain his immediate status. Shalk replied that he and his ship were OK, but the tower never heard his response. The pilot was finally able to turn the A-12 around and taxi back to the hangar area. The Lockheed test team knew that there was plenty to understand and do before the aircraft would be permitted to make its first flight!
Analysis showed that the aircraft (1) did not have its aerodynamic dampers switched to the ON position and (2) center-of-gravity (CG) was located significantly behind the aft CG limit. The former because most pilots would not engage dampers during the early stages of flight test of a new airplane. The latter because the fueling crew, expecting only a runway-hugging high-speed taxi test, had conveniently put most of the gas in the back of the airplane.
The No. 1 A-12 officially made its first flight on Wednesday, 30 April 1962. Take-off and recovery occurred at Groom Lake. The A-12 first achieved supersonic flight the next month. Following a brief, but intense, flight test program, the type entered the USAF operational inventory in 1963. The A-12 retired from active service in June of 1968. By that time, another triple-sonic aircraft had sprung from its loins. That aircraft was none other than the legendary SR-71 Blackbird.
Thirteen A-12 aircraft would ultimately be manufactured by Lockheed. Five of these aircraft were lost over the course of the type’s flying career. Remarkably, A-12 No.1 (S/N 60-6924) survived. In tribute, Lou Schalk’s A-12 first flight beauty is prominently displayed at Blackbird Airpark in Palmdale, California.
Fifty-four years ago this month, the USAF/Ryan X-13 Vertijet completed history’s first vertical-to horizontal-back to vertical flight of a jet-powered Vertical Take-Off and Landing (VTOL) aircraft. This event took place at Edwards Air Force Base, California with Ryan Chief Test Pilot Peter F. Girard at the controls.
The X-13 Vertijet was an experimental flight vehicle designed to determine the feasibility of a jet-powered Vertical Take-Off and Landing (VTOL) aircraft. The initial idea for the type dates back to 1947 when the United States Navy (USN) put Ryan under contract to explore the viability of a jet-powered VTOL aircraft. At the time, the Navy was quite interested in exploiting the VTOL concept for tactical advantage. The service envisioned basing VTOL aircraft on submarines and small surface ships.
The USN-Ryan team worked the X-13 VTOL concept for over six (6) years to good effect. While no flight vehicle took to the skies during that time, a great deal of progress was made in the realm of hovering flight using ground-based vertical test rigs. Particular effort was focused on VTOL low-speed flight controls. However, Navy research and development funding was slashed in the aftermath of the Korean War and the X-13 project ran out of money in the summer of 1953.
Fortunately, the United States Air Force (USAF) had become interested in the X-13 and the possibilities of VTOL flight prior to the Navy running out of money. The junior service assumed ownership of the X-13 effort after securing the funding required to continue the program. A pair of X-13 prototypes were subseqently built and flown by Ryan Aeronautical. These aircraft were assigned USAF serial numbers 54-1619 and 54-1620, respectively.
The X-13 measured 23.5 feet in length and had a wing span of 21 feet. The single-place aircraft featured a maximum take-off weight of approximately 7,300 pounds. Hovering flight control was provided via wing tip-mounted yaw and roll nozzles. The heart of the VTOL aircraft was its reliable Rolls-Royce Avon turbojet. The non-afterburning powerplant used standard JP-4 fuel and produced a maximum thrust of 10,000 pounds.
The X-13 was transported, launched and retrieved using a special flatbed trailer. Hinged at one end, the trailer was raised and lowered through the instrumentality of a pair of hydraulic rams. Once raised to a vertical position, the X-13 hung on its nose hook from a steel suspension cable stretched between two mechanical arms. Rather than landing gear, the aircraft sat on two non-retractable tubular bumpers positioned on the lower fuselage.
Flight testing of the No. 1 X-13 (S/N 54-1619) began on Saturday, 10 December 1955 at Edwards Air Force Base, California. The purpose of this initial flight was to test the X-13’s conventional flight characteristics. The aircraft was configured with tricycle landing to permit a runway take-off. Ryan Chief Test Pilot Peter F. “Pete” Girard flew a brief seven minute test hop in which he determined that the X-13 had serious control issues in all 3-axes. The subsequent installation of yaw and roll dampers fixed the problem.
The next phase of flight testing involved vertical hovering flight wherein aircraft handling and control characteristics were explored. For doing so, the X-13 was outfitted with a vertical landing gear system composed of a tubular support structure and a quartet of small caster-type wheels. Thus configured, the X-13 could take-off, hover and land in the vertical. As vertical flight testing progresed, important refinements were made to the aircraft’s turbojet throttling and reaction control systems.
The first vertical flight test was made on Monday, 28 May 1956 with the No. 1 aircraft. Pete Girard was again in the cockpit. Restricting maximum altitude to about 50 feet above ground level, Girard found the aircraft relatively easy to fly and land. Succeeding flight tests would ultimately include practice hook landings wherein a 1-inch thick manila rope suspended between a pair of 50-foot towers was engaged. A great deal of experience with and confidence in the X-13 system was accrued during these tests.
Prior to flying the X-13 all-up mission, an additional phase of flight testing was required which would culminate with the events of Monday, 28 November 1956. With the conventional landing gear installed on the No. 1 aircraft, Girard took-off from Edwards and climbed to 6,000 feet. He then slowly pitched the aircraft into the vertical and hovered for an extended period. Girard then executed a transition back to horizontal flight and landed. The first-ever horizontal-to vertical-back to horizontal flight transition was entirely successful.
The big day came on Thursday, 11 April 1957. Edwards Air Force Base again served as the test site. This time using the No. 2 X-13 (S/N 54-1620), Pete Girard took-off vertically, ascended in hovering flight and transitioned to conventional flight. Following a series of standard flight maneuevers, Girard transitioned the aircraft back into a vertical hover, descended and engaged the suspension cable on the support trailer with the aircraft’s nose hook. The first-ever vertical-to horizontal-back to vertical flight of a jet-propelled VTOL aircraft was history.
Both X-13 aircraft would go on to successfully conduct additional flight testing and stage numerous flight demonstrations during the remainder of 1957. However, innovative and impressive as it was, the X-13 did not garner the advocacy and backing required to proceed to production. A combination of bad timing, a risk averse military and combat performance limitations resulted in the aircraft and its technology quickly fading from the aviation scene.
Remarkably, both X-13 aircraft survived the type’s flight test program. The No. 1 aircraft (S/N 54-1619) is displayed at the San Diego Aerospace Museum in San Diego, California. The No. 2 X-13 aircraft (S/N 54-1620) is on display in the Annex section of the United States Air Force Museum at Wright-Patterson Air Force Base in Dayton, Ohio.
Forty-one years ago today, the crew of Apollo 13 left Earth headed for the Fra Mauro highlands of the Moon. Less than six days later, they would be back on Earth following an epic life and death struggle to survive the effects of an explosion that rocked their spacecraft 200,000 miles from home.
Apollo 13 was slated as the 3rd lunar landing mission of the Apollo Program. The intended landing site was the mountainous Fra Mauro region near the lunar equator. The Apollo 13 crew consisted of Commander James A. Lovell, Jr., Lunar Module Pilot Fred W. Haise, Jr. and Command Module Pilot John L. (Jack) Swigert, Jr. Lovell was making his fourth spaceflight (second to the Moon) while Haise and Swigert were space rookies.
Apollo 13 lifted-off from LC-39A at Cape Canaveral, Florida on Saturday, 11 April 1970. The official launch time was 19:13:00 UTC (13:13 CST). During second stage burn, the center engine shutdown two minutes early as a result of excessive longitudinal structural vibrations. The outer four J-2 engines burned 34 seconds longer to compensate. Arriving safely in low Earth orbit, Lovell observed that every mission seemed to have at least one major glitch. Clearly, Apollo 13’s was now out of the way!
The Apollo 13 payload stack consisted of a Command Module (CM), Service Module (SM) and Lunar Module (LM). The entire ensemble had a lift-off mass of nearly 49 tons. In keeping with tradition, the Apollo 13 crew gave call signs to their Command Module and Lunar Modules. This helped flight controllers distinguish one vehicle from the other over the communications net during mission operations. The CM was named Odyssey and the LM was given the name of Aquarius.
The first two days of the outward journey to the Moon were uneventful. In fact, some at Mission Control in Houston, Texas seemed somewhat bored. The same could be said for the ever-astute press corps who predictably reported that Americans were now responding to the lunar landing missions with a collective yawn. The journalistic sages averred that the space program needed some pepping-up. Going to the Moon might have been impossible yesterday, but today its just run-of-the-mill stuff. Actually, it was all kind of easy. So wrote they of the fickle Fourth Estate.
It all started with a bang at 03:07:53 UTC on Tuesday, 14 April 1970 (21:07:53 CST, 13 April 1970) with Apollo 13 distanced 200,000 miles from Earth. “Houston, we’ve had a problem here.” This terse statement from Jack Swigert informed Mission Control that something ominous had just occurred onboard Apollo 13. Jim Lovell reported that the problem was a “Main B Bus undervolt”. A potentially serious electrical system problem.
But what was the exact nature of the of problem and why did it occur? Nary a soul in the spacecraft nor in Mission Control could provide the answers. All anyone really knew at the moment was that two of three fuel cells formerly supplying electricity to the Command Module were now dead. Arguably more alarming, Oxygen Tank No. 2 was empty with Tank No. 1 losing oxygen at a high rate.
There was something else. The Apollo 13 reaction control system was firing in apparent response to some perturbing influence. But what was it? The answer came with all the subtleness of a sledge hammer blow. Jim Lovell reported that some kind of gas was venting from the spacecraft into space. That chilling observation suddenly explained why the No. 1 oxygen tank was losing pressure so rapidly.
Once Mission Control and the Apollo 13 astronauts fully comprehended the gravity of the situation, the entire team went to work to bring the spacecraft home. Odyssey was powered-down to conserve its battery power for reentry while Aquarius was powered-up and became a makeshift lifeboat. A major problem was that Aquarius had battery power and water sufficient for only 40 hours of flight. The trip home would take 90 hours.
Amazingly, engineering teams at Mission Control conceived and tested means to minimize electrical useage on Aquarius. However, the Apollo 13 crew would have to endure privation and hardships to survive. The cabin temperature in Aquarius got down to 38F and each man was permitted only six ounces of water per day. The walls of the spacecraft were covered with condensation. Sleep was almost impossible and fatigue became another lingering enemy to survival.
And then there was the build-up of carbon dioxide. The LM environmental system (EV) was designed to support two men. Now there were three. Between the CM and LM, there was an ample supply of lithium hydroxide canisters to scrub the gas from the cabin atmosphere for the trip home. However, the square CM canisters were incompatible with the circular openings on LM EV. The engineers on the ground invented a device to eliminate this compatibility using materials found onboard the spacecraft.
The Apollo 13 crew had to fire the LM descent motor several times in order to adjust their return trajectory. Use of the SM propulsion system to effect these firings was denied the crew due to concerns that the explosion could have damaged it. These rocket motor firings required precise inertial navigation. The star sightings required for celestial navigation were impossible to make owing to the hugh cloud of debris surrounding the spacecraft. Means were devised to use the Sun as the primary navigational source.
As the nation and indeed the world looked on, the miracle of Apollo 13 slowly unfolded. Many a humble heart uttered a prayer for and in behalf of the trio of astronauts. Millions throughout the world followed the men’s journey home via newspaper, radio, televison and other media.
As Apollo 13 approached the Earth, the overriding issue was whether the systems onboard Odyssey could be successfully brought back on line. The walls and instrument panels of the craft were drenched with condensation. Unquestionably, the electronics and wiring bundles behind those instrument panels were also soaking wet. Would they short-out once electrical energy flowed through them again? Would there be enough battery power for reentry?
Happily, the CM power-up sequence was successfully accomplished. Once again the resourceful engineers at Mission Control produced under extreme duress. They devised an intricate and never-attempted-in-flight power-up sequence for the CM. Too, the extra insulation added to the CM’s electrical system in the aftermath of the Apollo 1 fire provided protection from condensation-induced electrical arcing.
Approximately four hours prior to reentry, the Apollo 13 crew jettisoned the SM. What they saw was shocking. The module was missing a complete external panel and most of the equipment inside was gone or significantly damaged. One hour prior to entry, Aquarius, their trusty space lifeboat, was also jettsioned. The only concern now was whether the CM base heatshield had survived the explosion intact.
On Friday, 17 April 1970, Odyssey hit entry interface (400,000 feet) at 36,000 feet per second. Other than a worrisome additional 33 seconds of plasma-induced communications blackout (4 minutes, 33 seconds total), the reentry was entirely nominal. Splashdown occurred at 18:07:41 UTC near American Samoa in the Pacific Ocean. The USS Iwo Jima quickly recovered spacecraft and crew.
The post-flight mishap investigation revealed that Oxygen Tank No. 2 exploded when the crew conducted a cryo-stir of its multi-phase contents. Unkown to all was the fact that a mismatch between the tank heater and thermostat had resulted in the Teflon insulation of the internal wiring being severely damaged during previous ground operations. This meant that the tank was now a bomb and would detonate its contents when used the next time. In this case, the next time was in flight. The warning signs were there, but went unheeded.
Apollo 13 never landed at Fra Mauro. And none of its crew would ever again fly in space. But in many ways, Apollo 13 was NASA’s finest hour. Overcoming myriad seemingly intractable obstacles in the aftermath of a completely unanticipated catastrophe, deep in translunar space, will forever rank high among the legendary accomplishments of flight. With essentially no margin for error and in the harsh glare of public scrutiny, NASA wrested victory from the tenacles of almost certain failure and brought three weary men safely back to their home planet.
Twenty-seven years ago this week, the Solar Max satellite was retrieved from, repaired in and redeployed to orbit by the crew of STS 41-C. The historic event marked the first time in the annals of spaceflight that a satellite was repaired on-orbit.
Space Transportation System (STS) 41-C was one of the most eventful and historic missions of the Space Shuttle Program. The first Shuttle direct ascent was flown, a crippled satellite was repaired in orbit for the first time, a major space research facility was deployed and the famed IMAX camera was first used in space.
STS 41-C was the 11th Space Shuttle mission and the 5th flown by the Challenger orbiter. Mission Commander for STS 41-C was Robert L. Crippen, who was making his 3rd Shuttle flight. The other crew members were space rookies. They included Francis R. “Dick” Scobee, Pilot and Mission Specialists George D. “Pinkie” Nelson, James D. A. “Ox” van Hoften and Terry J. Hart.
STS 41-C was launched from LC-39A at Cape Canaveral, Florida on Friday, 06 April 1984. Lift-off time was 13:58 UTC. The direct ascent profile initially placed the Challenger in a 288-nm circular orbit. The Orbiter’s lift-off mass of 254,254 lbs included 57,279 lbs of payload.
After raising Challenger’s orbit to 313-nm, the STS 41-C crew performed a rendezvous with the malfunctioning Solar Maximum satellite on the third day of the mission. Using the newly-developed Manned Maneuvering Unit (MMU), Mission Specialist Nelson flew out to meet Solar Max which was stationed about 200 feet from the Orbiter. His intent was to grapple it and bring it back into the Challenger payload bay for repairs.
Nelson was equipped with a tool called the Trunnion Pin Acquisition Device (TPAD) for grappling the satellite. Three attempts using the TPAD failed. Apparently, ground-based drawings of the Solar Max grappling pin did not show a grommet that was installed on the actual flight hardware. This prevented the TPAD from working correctly.
When it became evdient that the TPAD would not work, Nelson attempted to grab Solar Max by hand. Unfortunately, this made matters worse as the satellite began tumbling about all three (3) axes. Nelson retired to the Orbiter and Shuttle Mission Control in Houston, Texas went to work on assessing the crew’s next move.
Overnight, Solar Max controllers at Goddard Space Flight Center in Greenbelt, Maryland managed to regain control of the tumbling satellite. In concert with this effort, Shuttle Mission Control in Houston came up with a revised plan to capture Solar Max and dock it in Challenger’s payload bay. The idea now was to grapple the satellite using the Orbiter’s Remote Manipulator System (RMS).
On the fourth day of flight, Mission Specialist Hart successfully grappled Solar Max with the RMS and berthed it in the aft part of the Orbiter’s payload bay. Nelson and van Hoften then went to work. In a space walk lasting almost seven (7) hours, the astronauts skillfully changed-out a faulty attitude control system and the electronics box on the satellite’s coronograph.
Solar Max was redeployed to orbit on Day 5 of STS 41-C. Following a 30-day checkout by Goddard flight controllers, the satellite resumed full operation. While certainly more difficult than expected, the Solar Max repair effort was an unqualified success. Following a mission of 6 days, 23 hours, 40 minutes and 7 seconds, Challenger safely landed at Edwards Air Force Base, California on Friday, 13 April 1984.
The Solar Max repair mission of April 1984 set the stage for more challenging and extensive future work in space. Indeed, three (3) successful Hubble Telescope repair and refurbishment missions as well as construction of the International Space Station (ISS) share an important experiential linkage with the pioneering STS 41-C effort.
Seven years ago this week, the NASA X-43A scramjet-powered flight research vehicle reached a record speed of over 4,600 mph (Mach 6.83). The test marked the first time in the annals of aviation that a flight-scale scramjet accelerated an aircraft in the hypersonic Mach number regime.
NASA initiated a technology demonstration program known as HYPER-X in 1996. The fundamental goal of the HYPER-X Program was to successfully demonstrate sustained supersonic combustion and thrust production of a flight-scale scramjet propulsion system at speeds up to Mach 10.
Also known as the HYPER-X Research Vehicle (HXRV), the X-43A aircraft was a scramjet test bed. The aircraft measured 12 feet in length, 5 feet in width, and weighed nearly 3,000 pounds. The X-43A was boosted to scramjet take-over speeds with a modified Orbital Sciences Pegasus rocket booster.
The combined HXRV-Pegasus stack was referred to as the HYPER-X Launch Vehicle (HXLV). Measuring approximately 50 feet in length, the HXLV weighed slightly more than 41,000 pounds. The HXLV was air-launched from a B-52 mothership. Together, the entire assemblage constituted a 3-stage vehicle.
The second flight of the HYPER-X program took place on Saturday, 27 March 2004. The flight originated from Edwards Air Force Base, California. Using Runway 04, NASA’s venerable B-52B (S/N 52-0008) started its take-off roll at approximately 20:40 UTC. The aircraft then headed for the Pacific Ocean launch point located just west of San Nicholas Island.
At 21:59:58 UTC, the HXLV fell away from the B-52B mothership. Following a 5 second free fall, rocket motor ignition occurred and the HXLV initiated a pull-up to start its climb and acceleration to the test window. It took the HXLV about 90 seconds to reach a speed of slightly over Mach 7.
Following rocket motor burnout and a brief coast period, the HXRV (X-43A) successfully separated from the Pegasus booster at 94,069feet and Mach 6.95. The HXRV scramjet was operative by Mach 6.83. Supersonic combustion and thrust production were successfully achieved. Total engine-on duration was approximately 11 seconds.
As the X-43A decelerated along its post-burn descent flight path, the aircraft performed a series of data gathering flight maneuvers. A vast quantity of high-quality aerodynamic and flight control system data were acquired for Mach numbers ranging from hypersonic to transonic. Finally, the X-43A impacted the Pacific Ocean at a point about 450 nautical miles due west of its launch location. Total flight time was approximately 15 minutes.
The HYPER-X Program made history that day in late March 2004. Supersonic combustion and thrust production of an airframe-integrated scramjet were achieved for the first time in flight; a goal that dated back to before the X-15 Program. Along the way, the X-43A established a speed record for airbreathing aircraft and earned a Guinness World Record for its efforts.
Fifty-three years ago this week, Explorer III became the third artificial satellite to be successfully orbited by the United States. Interestingly, this early trio of successful orbital missions had been achieved in a period of less than 60 days.
The early Explorer satellites (Explorer I, II and III) were designated as Explorer A spacecraft. Their primary mission was to study the Earth’s Magnetosphere. Each satellite measured about 81-inches in length and had a maximum diameter of 6.5-inches. On-orbit weight was close to 31 pounds.
Explorer satellite instrumentation was modest. The primary instruments carried included a cosmic ray detector and micrometeorite erosion gauges. Data were transmitted to Earth using a 60 milliwatt dipole antenna transmitter and a 10 milliwatt turnstile transmitter. Electrical power was provided by mercury chemical batteries that accounted for roughly 40 percent of the payload weight.
Explorer I was the first artificial satellite to achieve Earth orbit. The satellite was launched atop a Jupiter-C launch vehicle on Friday, 31 January 1958 from LC-26A at Cape Canaveral, Florida. The country’s first satellite quickly went to work and discovered what we know today as the Van Allen Radiation Belts.
Explorer II was to verify and expand upon the findings of Explorer I. However, the craft never achieved orbit after it was launched on Wednesday, 05 March 1958. The cause was attributed to a failure in the 4th stage of its Jupiter-C launch vehicle. While the outcome was disappointing, the Explorer Program quickly readied another Explorer satellite for flight.
Explorer III was launched from Cape Canaveral’s LC-5 on Wednesday, 26 March 1958 at 17:31 UTC. The Jupiter-C launch vehicle performed admirably and delivered Explorer III into a highly elliptical 1,511-nm x 100-nm orbit. However, all was not well in orbit. Telemetry data indicated that the pencil-like satellite was tumbling at a rate of about 1 cycle every 7 seconds.
Explorer III performed its intended mission in spite of the anomalous tumbling motion. Indeed, the craft corroborated the findings of Explorer I and helped verify the existence of the Van Allen Radiation belts. However, the unwanted tumbling increased Explorer III’s aerodynamic drag and significantly shortened its mission lifetime.
Explorer III’s orbit decayed to the point that it reentered the Earth’s atmosphere on Tuesday, 27 June 1958. During its 93 days in space, the spacecraft made approximately 1,160 trips around the Earth.
Forty-five years ago this week, the crew of Gemini VIII successfully regained control of their tumbling spacecraft following failure of an attitude control thruster. The incident marked the first life-threatening on-orbit emergency and resulting mission abort in the history of Amercian manned spaceflight.
Gemini VIII was the sixth manned mission of the Gemini Program. The primary mission objective was to rendezvous and dock with an orbiting Agena Target Vehicle (ATV). Successful accomplishment of this objective was seen as a vital step in the Nation’s quest for landing men on the Moon.
The Gemini VIII crew consisted of Command Pilot Neil A. Armstrong and Pilot USAF Major David R. Scott. Both were space rookies. To them would go both the honor of achieving the first successful docking in orbit as well as the challenge of dealing with the first life and death space emergency involving an American spacecraft.
Gemini VIII lifted-off from Cape Canaveral’s LC-19 at 16:41:02 UTC on Wednesday, 16 March 1966. The crew’s job was to chase, rendezvous and then physically dock with an Agena that had been launched 101 minutes earlier. The Agena successfully achieved orbit and waited for Gemini VIII in a 161-nm circular Earth orbit.
It took just under six (6) hours for Armstrong and Scott to catch-up and rendezvous with the Agena. The crew then kept station with the target vehicle for a period of about 36 minutes. Having assured themselves that all was well with the Agena, the world’s first successful docking was achieved at a Gemini mission elasped time of 6 hours and 33 minutes.
Once the reality of the historic docking sank in, a delayed cheer erupted from the NASA and contractor team at Mission Control in Houston, Texas. Despite the complex orbital mechanics and delicate timing involved, Armstrong and Scott had made it look easy. Unfortunately, things were about to change with chilling suddeness.
As the Gemini crew maneuvered the Gemini-Agena stack, their instruments indicated that they were in an uncommanded 30-degree roll. Using the Gemini’s Orbital Attiude and Maneuvering System (OAMS), Armstrong was able to arrest the rolling motion. However, once he let off the restoring thruster action, the combined vehicle began rolling again.
The crew’s next action was to turn off the Agena’s systems. The errant motion subsided. Several minutes elapsed with the control problem seemingly solved. Suddenly, the uncommanded motion of the still-docked pair started again. The crew noticed that the Gemini’s OAMS was down to 30% fuel. Could the problem be with the Gemini spacecraft and not the Agena?
The crew jettisoned the Agena. That didn’t help matters. The Gemini was now tumbling end over end at almost one revolution per second. The violent motion made it difficult for the astronauts to focus on the instrument panel. Worse yet, they were in danger of losing consciousness.
Left with no other alternative, Armstrong shut down his OAMS and activated the Reentry Control System reaction control system (RCS) in a desperate attempt to stop the dizzying tumble. The motion began to subside. Finally, Armstrong was able to bring the spacecraft under control.
That was the good news. The bad news for the crew of Gemini VIII was that the rest of the mission would now have to be aborted. Mission rules dictated that such would be the case if the RCS was activated on-orbit. There had to be enough fuel left for reentry and Gemini VIII had just enough to get back home safely.
Gemini VIII splashed-down in the Pacific Ocean 4,320 nm east of Okinawa. Mission elapsed time was 10 hours, 41 minutes and 26 seconds. Spacecraft and crew were safely recovered by the USS Leonard F. Mason.
In the aftermath of Gemini VIII, it was discovered that OAMS Thruster No. 8 had failed in the ON position. The probable cause was an electrical short. In addition, the design of the OAMS was such that even when a thruster was switched off, power could still flow to it. That design oversight was fixed so that subsequent Gemini missions would not be threatened by a reoccurence of the Gemini VIII anomaly.
Neil Armstrong and David Scott met their goliath in orbit and defeated the beast. Armstrong received a quality increase for his efforts on Gemini VIII while Scott was promoted to Lieutenant Colonel. Both men were awared the NASA Exceptional Service Medal.
More significantly, their deft handling of the Gemini VIII emergency elevated both Armstrong and Scott within the ranks of the astronaut corps. Indeed, each man would ultimately land on the Moon and serve as mission commander in doing so; Neil Armstrong on Apollo 11 and David Scott on Apollo 15.
Forty-nine years ago today, the United States successfully launched Orbiting Solar Observatory No. 1 (OSO-1) into Earth orbit. This robotic spacecraft provided the first detailed scientific examination of the Sun from space.
The 1960’s was a time of both rapid growth and spectacular achievements in space exploration. Indeed, weather satellites, communications satellites and surveillance satellites were new inventions. Robotic space probes were sent to orbit and land on the Moon. Other autonomous spacecraft visited the inner planets of the Solar System. Men orbited the Earth. Still others landed on and returned from the Moon.
Space probes were also employed to good effect in an effort to learn more about our Sun. NASA’s Orbiting Solar Observatory (OSO) Program was America’s first attempt to acquire detailed solar physics data using orbital spacecraft. A total of eight (8) OSO space probes were launched into Earth orbit between 1962 and 1975.
The fundamental objective of the OSO Program was to monitor and measure solar electromagnetic radiation levels over an 11-year sun spot cycle. The idea was to map the direction and intensity of Ultraviolet, X-Ray and Gamma radiation throughout the celestial sphere over the long solar cycle. Onboard scientific instrumentation included a solar spectrometer, scintillation detector, proton electron analyzer and various flux monitors
OSO satellites were relatively large and complex for their time. Spacecraft attitude had to be tightly controlled since onboard instrument systems needed to be continuously trained on the solar disk. The probe’s solar physics data could be transmitted to ground receiving stations in real-time or recorded on tape for later transmittal.
OSO-1 was the first solar observatory orbited by the United States. Launch from Cape Canaveral’s LC-17A took place on Wednesday, 07 March 1962 at 16:04:00 UTC. A Thor-Delta 301/D8 launch vehicle placed the 458-lb OSO-1 satellite into a near circular Earth orbit (291-nm x 275-nm). The orbital period of 94.7 minutes meant that OSO-1 orbited the Earth 15.2 times each day.
OSO-1 performed well until its second onboard tape recorder gave up the ghost. This anomaly occurred on Tuesday, 15 May 1962. The loss of its last functional data recorder meant that all subsequent measurements had to be transmitted in real-time.
OSO-1 would continue making and transmitting solar physics measurements until May of 1964. At that time, the spacecraft power supply died when its solar cells failed. Although dormant, OSO-1 would continue to orbit the Earth for another seventeen (17) years. The spacecraft reentered the Earth’s atmosphere on Thursday, 08 October 1981.
OSO-1 and all succeeding OSO satellites contributed significantly to progress in the realm of solar physics. The OSO Program laid the foundation for more sophisticated and detailed study of our Sun through the auspices of such solar probes as SOHO, Ulysses and Skylab. Indeed, NASA’s Solar Probe Plus probe, currently scheduled to fly within the Sun’s coronal region sometime in the 2015/2016 period, will continue the legacy begun long ago by OSO-1.
Fifty-five years ago this month, the USAF/North American X-10 experimental research vehicle hit a maximum speed of Mach 2.05 during its 19th test flight. The mark established a new speed record for turbojet-powered aircraft.
The precedent set by the Nazi V-1 and V-2 Vergeltungswaffen (Vengeance Weapons) in World War II motivated the United States to launch a post-war effort to develop a strategic range-capable missile capability. The earliest example in this regard was the USAF/North American Navaho (SM-64).
Known as Project MX-770, the Navaho was developmental effort to deliver a nuclear warhead at a range of 5,500 nm. The Navaho configuration consisted of a rocket-powered first stage and a winged second stage utilizing ramjet propulsion. The second stage was designed to cruise at Mach 2.75.
The X-10 was a testbed version of the Navaho second stage. The X-10 measured 66 feet in length, sported a wingspan of 28 feet and had a GTOW of 42,000 lbs. The sleek aircraft was powered by twin Westinghouse J40-WE-1 turbojets. These powerplants burned JP-4 and were each rated at 10,900 lbs of sea level thrust in full afterburner.
The X-10 was a double sonic-capable aircraft. It had an unrefueled range of 850 miles and a maximum altitude capability of 44,800 feet.
The X-10 vehicle flight surfaces included elevons for pitch and roll control and twin rudders for yaw control. Canard surfaces were employed for pitch trim. The aircraft was designed to take-off, maneuver and land under external control provided by either airborne or ground-based assets.
A total of thirteen (13) X-10 airframes were constructed by North American. Flight testing originated at the Air Force Flight Test Center (AFFTC), Edwards Air Force Base, California and later moved to the Air Force Missile Test Center (AFMTC) at Cape Canaveral in Florida.
There was a total of twenty-seven (27) X-10 flight tests. Fifthteen (15) flight tests took place at the AFFTC between October of 1953 and March of 1955. Twelve (12) flight tests were conducted at the AFMTC between August 1955 and November 1956.
X-10 airframe GM-52-1 achieved the highest speed of the type’s flight test series. On Wednesday, 29 February 1956, the aircraft recorded a peak Mach Number of 2.05 during the 19th flight test of the X-10 Program. At the time, this was a record for turbojet-powered aircraft. The mission originated from and recovered to the AFMTC.
While the X-10 Program produced a wealth of aerodynamic, structural, flight control and flight performance data, test vehicle attrition was extremely high. The lone X-10 to survive flight testing was airframe GM-19307. It is currently on display at the Museum of the United States Air Force at Wright-Patterson Air Force Base in Dayton, Ohio.
Fifty-six years ago this week, North American test pilot George F. Smith became the first man to survive ejection from an aircraft in supersonic flight. Smith ejected from his F-100A Super Sabre at 777 MPH (Mach 1.05) as the crippled aircraft passed through 6,500 feet in a near-vertical dive.
On the morning of Saturday, 26 February 1955, North American Aviation (NAA) test pilot George F. Smith stopped by the company’s plant at Los Angeles International Airport to submit some test reports. Returning to his car, he was abruptly hailed by the company dispatcher. A brand-new F-100A Super Sabre needed to be test flown prior to its delivery to the Air Force. Would Mr. Smith mind doing the honors?
Replying in the affirmative, Smith quickly donned a company flight suit over his street clothes, got the rest of his flight gear and pre-flighted the F-100A Super Sabre (S/N 53-1659). After strapping into the big jet, Smith went through the normal sequence of aircraft flight control and system checks. While the control column did seem a bit stiff in pitch, Smith nonetheless made the determination that his steed was ready for flight.
Smith executed a full afterburner take-off to the west. The fleet Super Sabre eagerly took to the air. Accelerating and climbing, the aircraft was almost supersonic as it passed through 35,000 feet. Peaking out around 37,000 feet, Smith sensed a heaviness in the flight control column. Something wasn’t quite right. The jet was decidely nose heavy. Smith countered by pulling aft stick.
The Super Sabre did not respond at all to Smith’s control inputs. Instead, it continued an uncommanded dive. Shallow at first, the dive steepened even as the 215-lb pilot pulled back on the stick with all of his might. But all to no avail. The jet’s hydraulic system had failed. As the stricken aircraft now accelerated toward the ground, Smith rightly concluded that this was going to be a short ride.
George Smith knew that he had only one alternative now. Eject. However, he also knew that the chances were small that he could survive what was quickly shaping-up to be a quasi-supersonic ejection. Suddenly, over the radio, Smith heard another F-100A pilot flying in his vicinity yell: “Bail out, George! He proceeded to do so.
Smith jettisoned his canopy. The roar from the airstream around him was unlike anything he had ever heard. Almost paralyzed with fear, Smith reflexively hunkered-down in the cockpit. The exact wrong thing to do. His head needed to be positioned up against the seat’s headrest and his feet placed within retraining stirrups prior to ejection. But there was no time for any of this now. Smith pulled the ejection seat trigger.
George Smith’s last recollection of his nightmare ride was that the Mach Meter read 1.05; 777 mph at the ejection altitude of 6,500 feet above the Pacific Ocean. These flight conditions corresponded to a dynamic pressure of 1,240 pounds per square foot. As he was fired out of the cockpit and into the harsh airstream, Smith was subjected to a drag force of around 8,000 lbs producing on the order of 40-g’s of deceleration.
Mercifully, Smith did not recall what came next. The ferocious windblast stripped him of his helmet, oxygen mask, footwear, flight gloves, wrist watch and even his ring. Blood was forced into his head which became grotesquely swollen and his facial features unrecognizable. His eyelids fluttered and his eyes were tortuously mauled by the aerodynamic and inertial load of his ejection. Smith’s internal organs, most especially his liver, were severely damaged. His body was horribly bruised and beaten as it flailed end-over-over end uncontrollably.
Smith and his seat parted company as programmed followed by automatic deployment of his parachute. The opening forces were so high that a third of the parachute material was ripped away. Thankfully, the remaining portion held together and the unconscious Smith landed about 75 yards away from a fishing vessel positiond about a half-mile form shore. Providentially, the boat’s skipper was a former Navy rescue expert. Within a minute of hitting the water, Smith was rescued and brought onboard.
George Smith was hovering near death when he arrived at the hospital. In severe shock and with only a faint pulse, doctors quickly went to work. Smith awoke on his sixth day of hospitalization. He could hear, but he couldn’t see. His eyes had sustained multiple subconjunctival hemorrhages and the prevailing thought at the time was that he would never see again.
Happily, George Smith did recover almost fully from his supersonic ejection experience. He spent seven (7) months in the hospital and endured several operations. During that time, Smith’s weight dropped to 150 lbs. He was left with a permanently damaged liver to the extent that he could no longer drink alcohol. As for Smith’s vision, it returned to normal. However, his eyes were ever after somewhat glare-sensitive and slow to adapt to darkness.
Not only did George Smith return to good health, he also got back in the cockpit. First, he was cleared to fly low and slow prop-driven aircraft. Ultimately, he got back into jets, including the F-100A Super Sabre. Much was learned about how to markedly improve high speed ejection survivability in the aftermath of Smith’s supersonic nightmare. He in essence paid the price so that others would fare better in such circumstances as he endured.
George Smith was thirty-one (31) at the time of his F-100A mishap. He lived a happy and productive thirty-nine (39) more years after its occurrence. Smith passed from this earthly scene in 1994.
