Sixty-two years this week, the No. 2 USAF/Northrop X-4 experimental flight research aircraft took to the air for the first time. The flight of the second X-4 prototype originated from and recovered at Muroc Air Force Base, California.
The USAF/Northrop X-4 was an early X-plane designed to explore the flight characteristics of a swept-wing, tailless aircraft in transonic flight. It came into being as a result of recent Air Force studies which indicated that a tailless configuration might alleviate or eliminate instability issues associated with supersonic flight. The X-4’s external configuration was similar to that of the German Me163 Komet and the British De Havilland DH.108 Swallow.
The USAF contracted with the Northrop Aircraft Company in June of 1946 to construct and perform initial flight testing of two (2) X-4 aircraft. Northrop received the sole-source contract principally because of the company’s vast experience with flying-wing aircraft. Notable examples include the N-1M, XP-79B, XP-56 and the fabled B-35 heavy bomber.
The X-4 was a physically small airplane. As such, it received the nickname Bantam. It measured 23.25-feet in length and had a wing span of 26.75-feet. The wing leading edge sweep angle was 40.5-degrees. Gross take-off weight was 7,820 lbs. Power was provided by a pair of Westinghouse J30-WE-9 non-afterburning turbojets. Each powerplant had a sea level thrust rating of a paltry 1,600-lbs.
Due to the absence of a horizontal tail and an associated elevator, the X-4 was configured with wing-mounted elevons (combined elevator and aileron). These surfaces provided both pitch and roll control. The type’s split trailing edge flaps were used for low-speed lift enhancement as well as speed brake control. Aircraft directional control was provided via a standard vertical tail-mounted rudder.
The No. 1 X-4 aircraft (S/N 46-676) first flew on Wednesday, 15 December 1948 at Muroc Air Force Base, California. Northrop test pilot Charles Tucker was at the controls. The X-4’s first mission revealed that the aircraft was slightly unstable in pitch. Moving the center-of-gravity forward by 3-inches corrected this problem on subsequent X-4 flights.
The No. 2 X-4 aircraft (S/N 46-677) took to the skies over Muroc Air Force Base for the first time on Tuesday, 07 June 1949 with Northrop’s Charles Tucker once again doing the honors. The second X-4 prototype’s air worthiness characteristics and handling qualities were found to be entirely satisfactory.
This vehicle was in fact superior to the No. 1 aircraft in several respects. Not the least of which was a better flight instrumentation suite.
A total of 17 pilots flew the X-4. Northrop’s Charles Tucker piloted all 30 of the contractor flights including 10 in the No. 1 ship and 20 in the No. 2 X-4. The remaining 82 flights were all flown in the No. 2 ship by USAF and NACA pilots including such luminaries as Stanley Butchart (NACA), Scott Crossfield (NACA), Pete Everest (USAF), Jack McKay (NACA), Joe Walker (NACA) and Chuck Yeager (USAF).
The X-4 achieved a maximum altitude of 42,300 on Tuesday, 29 May 1951 and a maximum speed of Mach 0.94 on Monday, 22 September 1952. NACA pilot Scott Crossfield, who piloted the most X-4 flights (31), was at the controls in both instances.
The X-4 handled well below Mach 0.87. However, the aircraft exhibited an annoying porpoising in pitch at higher transonic speeds. Nose-down pitch changes also produced a Mach-tuck effect that worsened with increasing Mach number. The X-4 also had a nasty tendency to pitch-up as it approached sonic speed. These issues were all related in one way or another to the type’s unique tailless, swept wing configuration.
The X-4 flight test program officially ended in September of 1953. Of the 112 total flight tests conducted over the program’s 58-month duration, 102 were flown by the No. 2 ship. While the X-4 never flew supersonically, the type’s transonic flight research program revealed that the hoped-for advantages of a tailless aircraft in supersonic flight were specious.
Happily, both X-4 aircraft survived the flight test program intact. X-4 No. 1 (S/N 46-676) is currently on display at the United States Air Force Academy in Colorado Springs, CO. The No. 2 ship can be seen at the National Museum of the United States Air Force located at Wright-Patterson Air Force Base in Dayton, OH.
Forty years ago today, the United States launched the Mariner 9 spacecraft on a mission to Mars. Among other achievements, Mariner 9 would become the first terrestrial spacecraft to orbit another planet other than Earth.
The Mariner Program was a NASA project whose goal was to investigate the planets Mars, Venus and Mercury from space. A total of ten (10) Mariner spacecraft were launched between 1962 and 1973. Seven (7) of these pioneering missions were considered successful. The first interplanetary flyby, the first orbiting of another planet and the first gravity assist maneuver were all accomplished by Mariner spacecraft.
Each Mariner was built around a central bus or housing that was either hexagonal or octagonal in shape. All spacecraft guidance, navigation, propulsion, communication, power and instrumentation systems were contained within or attached to this central bus. Mariner spacecraft were typically configured with a set of four (4) solar panels for power. However, Mariner’s 1, 2 and 10 used just two (2). Cameras were carried by all Mariner space probes with the exception of Mission’s 1, 2 and 5.
Mariner 9 carried a scientific instrumentation package that consisted principally of an imaging system, ultraviolet spectrometer, infrared spectrometer and infrared radiometer. Fully deployed, each pair of solar panels measured 22.6-feet across. These panels provided 800 watts of power at Earth and 500 watts at Mars. Power was stored in a 20-amp-hour nickel-cadmium battery.
Mariner 9 lift-off mass was 2,196 lbs. Propellant useage during the flyout to Mars resulted in a spacecraft mass of 1,232 lbs in Martian orbit. Scientific instrumentation accounted for 139-lbs of the on-rbit mass. Spacecraft propulsion for mid-course corrections and orbital insertion was provided by a 300-lb thrust liquid rocket motor burning monomethyl hydrazine and nitrogen tetroxide. Mariner 9’s 3.28-foot diameter antenna telemetered data back to Earth at rates of 1, 2, 4, 8 or 16 kilobits/second using dual S-band 10 watt and 20 watt transmitters.
Mariner 9 was launched from Cape Canaveral’s LC-36B at 22:23:00 UTC on Sunday, 30 May 1971. An Atlas-Centaur SLV-3C launch vehicle provided the propulsive energy required to climb out of the Earth’s gravity well and send the probe on its way to Mars. It would take Mariner 9 roughly 167 Earth days to travel a distance of 214.85 million nautical miles to the Red Planet.
Mariner 9 entered Mars orbit at 00:18:00 UTC on Sunday, 14 November 1971. This marked the first time that a terrestrial spacecraft had achieved orbit about another planet in our Solar System other than Earth. Initial orbital parameters included an apoapsis of 9,672-nm and a periapsis of 755-nm at an inclination of 64.3 degrees. Interestingly, Mariner 9 arrived ahead of the Soviet Mars 2 space probe despite the latter’s eleven (11) day head start.
A planet-wide dust storm greeted Mariner 9 upon its arrival in Mars orbit. Hence, imaging of the planetary surface did not begin in earnest until late November. However, it was not until mid-January 1972 that the storm had subsided to the point that high quality images could be obtained from orbit.
Mariner 9 ultimately took 7,329 images which covered 100% of the Martian surface. The photos revealed a fascinating planetary topology that featured river beds, craters, extinct volcanoes, mountains and canyons. Mariner 9 discovered Olympus Mons, the largest known extinct volcano in the Solar System. Valles Marineris, a system of Martian canyons measuring 2,170-nm in length, was named after Mariner 9 in tribute to the probe’s significant space exploration accomplishments. Photographed as well were the diminutive Martian moons of Phobos and Deimos.
Upon depletion of its attitude control system propellant supply, Mariner 9’s mission was officially terminated when the spacecraft’s systems were turned-off on Friday, 27 October 1972. Total time spent investigating the Martian environment from orbit was 349-days. Though long silent, the craft remains in orbit around the Red Planet. It is expected to continue to do so through approximately the year 2022.
Forty-seven years ago this month, the No. 1 USAF/North American XB-70A Valkyrie aircraft was officially unveiled to the aviation public in a rollout ceremony conducted at USAF Plant 42 in Palmdale, California. The Great White Bird’s public debut occurred on Thursday, 11 May 1964.
The XB-70A Valkyrie was designed as an intercontinental bomber. Its original mission was to penetrate Soviet airspace and drop nuclear ordinance at Mach 3 and 70,000 feet. However, that mission was cancelled before the type ever flew. It was ultimately relegated to the status of an experimental flight research vehicle.
The XB-70A graced the skies of America between September 1964 and February 1969. It is to this day the largest triple-sonic aircraft ever flown. The aircraft measured 189 feet in length and had wing span of 105 feet. Gross weight topped out at around 540,000 lbs. Over half of that weight (290,000 lbs) was JP-6 jet fuel.
The Valkyrie was powered by six (6) General Electric YJ93 all-afterburning turbojets. These engines were designed to operate in continuous afterburner at Mach 3.2 and 95,000 feet. Total sea level thrust of the “6-Pack” was in excess of 185,000 lbs. The YJ93 was a contemporary of the Pratt and Whitney J58 turboramjet which powered the fabled USAF/Lockheed SR-71 Blackbird.
Only a pair of XB-70A airframes were built and flown; Air Vehicle No. 1 (S/N 62-0001) and Air Vehicle No. 2 (S/N 62-207). Together, these aircraft flew 129 flight tests totaling 252.6 flight hours. Ship No. 1 flew two-thirds of the XB-70A flight tests. The highest Mach number achieved during the XB-70A flight test program was Mach 3.08. This feat was accomplished by Ship No. 2 on Tuesday, 12 April 1966.
XB-70A Ship No. 2 also achieved the highest altitude of the XB-70A Program. Specifically, this aircraft attained a cruise altitude of 74,000 feet on Saturday, 19 March 1966. This mission included 32 minutes of continuous Mach 3 flight.
Eight (8) men flew the XB-70A. This line-up included Alvin S. White and Van H. Shepard of North American, Col Joseph E. Cotton, Lt Col Fitzhugh L. Fulton, Lt Col Emil (Ted) Sturnthal and Maj Carl S. Cross of the United States Air Force, and Joseph A. Walker and Donald L. Mallick of NASA.
The Valkyrie pioneered the use of numerous technologies including exploitation of the NACA Compression Lift Principle, development of honeycomb sandwich structural materials, and use of its fuel as a heat sink. The XB-70A was also used as a testbed for sonic boom research and a myriad of other aerodynamic and aerothermodynamic experiments. The Valkyrie also provided significant support to the ill-fated American Supersonic Transport (SST) effort.
XB-70A Ship No. 2 was lost in a collision with a NASA F-104N Starfighter near Edwards Air Force Base on Wedneday, 08 June 1966. This mishap took the lives of Maj Carl S. Cross and Joseph A. Walker on what is still referred to as the “Blackest Day at Edwards”. Ship No. 1 survived the XB-70 flight test program and is displayed today at the National Museum of the United States Air Force in Dayton, Ohio.
Forty-nine years ago this month, Mercury Astronaut M. Scott Carpenter orbited the Earth three times aboard his Aurora 7 Mercury spacecraft. In doing so, Carpenter became the second American to reach Earth orbit.
Project Mercury was America’s first manned spaceflight program. A total of six (6) flights took place between May of 1961 and May of 1963. The first two (2) flights were suborbital missions while the remainder achieved low Earth orbits. In February of 1962, John H. Glenn, Jr. became the first American to orbit the Earth during the Mercury-Atlas 6 (MA-6) mission.
Deke Slayton was to fly the Mercury-Atlas 7 (MA-7) mission. However, before that happened, the dreaded flight surgeon cabal grounded Slayton for what they claimed was a heart murmur. Despite Slayton’s utter incredulity and vehement protests, the decision held. Project Mercury officials maintained that the space program could ill afford the negative political fallout occasioned by the death of an astronaut on-orbit.
With Slayton grounded indefinitely, NASA selected Malcom Scott Carpenter to pilot the Mercury-Atlas 7 mission. Carpenter was member of the Original Seven selected by NASA for the Mercury Program in 1959. He was well prepared for the flight since he had just trained as Glenn’s MA-6 backup. As was the practice at that time, Carpenter named his Mercury spacecraft. The appellation he gave his celestial chariot was Aurora 7.
The launch of MA-7 took place on Thursday, 24 May 1962 from LC-14 at Cape Canaveral, Florida. Lift-off time was 12:45:16 UTC. Ascent performance of the stage-and-a-half Atlas D booster was nearly flawless as it inserted Aurora 7 into a 140-nm x 83-nm elliptical orbit. Having been cleared for at least 3 orbits, Carpenter quickly got down to the business of spaceflight.
Much of the activity on the first and second orbits involved Carpenter maneuvering his spacecraft, conducting scientific experiments and observing the Earth from space. Among other discoveries, he discerned that John Glenn’s mysterious “fireflies” were simply particles of ice and frost that had accumulated on the shadow side of the spacecraft. When the spacecraft structure was bumped or vibrated, these particles would disperse from the external surface of the spacecraft and float into space. Once in the strong sunlight, the particles seemed to glow or be luminescent.
A combination of the astronaut’s spacecraft maneuvering and an intermittently malfunctioning pitch horizon scanner left Carpenter with less than half of his maneuvering fuel left at the start of the third and final orbit. Carpenter compensated admirably by barely using his thrusters during Orbit 3. Indeed, nearing the time of retro-fire, Aurora 7 still had 40 percent of his fuel remaining in both the manual and automatic flight control systems.
As retro-fire approached, the intermittent pitch horizon scanner malfunction reappeared at a most inopportune moment. The automatic stabilization and control system suddenly would not hold Aurora 7 in the proper attitude for retro-fire; heatshield 34 degrees above the horizon at zero yaw angle. Carpenter switched to manual mode in an attempt to align the spacecraft properly for retro-fire.
When nominal time for retro-fire came, the retro-rockets did not automatically ignite. Carpenter had to do that manually. But he was 3 seconds late. Worst, Aurora 7 was still yawed 25 degree to the right. And to top it off, retro-thrust was 3 percent low. All of this meant that Aurora 7 would overshoot the nominal landing point by 215 nautical miles.
The trip down through the atmosphere was sporty in that Carpenter ran out of attitude control system fuel early during the descent. This meant that there was no means to propulsively damp the side-to-side oscillations that the Mercury spacecraft normally exhibited during reentry. These oscillations became dangerous when they exceeded about 10 degrees. That is, the spacecraft could tumble end-over-end if left unchecked.
Carpenter simultaneously eyed the altimeter and spacecraft angle-of-attack. As the latter built-up dangerously, his only recourse was to manually fire the drogue earlier than planned in attempt to arrest Aurora 7’s oscillatory motion. He did so at 25,000 feet. The spacecraft’s side-to-side oscillations were stopped. Carpenter then deployed his main parachute at 9,500 feet. Splashdown occurred at 17:41:21 UTC at a point 108 nautical miles northeast of Puerto Rico.
Since Aurora 7 was listing badly and help was about an hour away, Carpenter extricated himself from the spacecraft and deployed his life raft. While a radio beacon helped recovery forces locate him, there was no voice communication between the astronaut and his rescuers. Carpenter was on the water nearly 3 hours before being picked-up by rescue helicopters and delivered to the carrier USS Intrepid. Some six (6) hours later, Aurora 7 was brought onboard the USS John R. Pierce.
Mercury-Atlas 7 was Scott Carpenter’s only space mission. A combination of factors, including less than amicable relations with Mercury Mission Control management, led to this being the case. During the intervening years, many stories alluding to pilot error or inattention as the cause of Aurora 7’s landing overshoot have been circulated. Indeed, much like Gus Grissom’s experience with the loss of his Liberty Bell spacecraft, these stories and explanations have been around long enough that they are now accepted as the “truth”.
Criticism of another’s performance comes easily in this world. However, as Theodore Roosevelt pointed out, it really is “The Man in the Arena” that counts most. In Scott Carpenter’s case, we simply turn the reader’s attention to NASA’s own post-flight report entitled “The Results of the United States Second Manned Orbital Mission”. Among other things, the subject report concluded that the Aurora 7 pilot overcame a “mission critical malfunction” of the pitch horizon scanner and “achieved all mission objectives”. And may we say that in so doing, Scott Carpenter’s MA-7 experience provides yet another validation of the man-in-the-loop concept so critical to the success of manned space operations.
Sixty-one years ago this month, Viking No. 4 soared to a record altitude of 91.2 nautical miles following launch from the USS Norton Sound. Known as Project Reach, the flight was conducted by the United States Navy to demonstrate the feasibility of using ship-launched rockets to carry scientific payloads into space.
The Viking rocket was the first large-scale, liquid-fueled launch vehicle to be developed by the United States. It’s primary mission was to carry scientific instrumentation and research payloads to altitudes as high as 140-nm. As such, the Viking was the domestic follow-on to the V2’s captured from Germany and flown on scientific missions from White Sands Proving Ground (WSPG) in New Mexico.
The Glenn L. Martin developed and built the Viking rocket for the United States Navy. The contract for doing so was let in August of 1946. A total of 12 airframes were built for the Viking Program. The Naval Research Laboratory (NRL) flew 11 of these vehicles between May of 1949 and February of 1955.
There were actually two Viking airframe configurations. The first 7 vehicles measured 47.5 feet in length and had a diameter of 32 inches. Depending on payload and propellant load, gross weight varied between 9,650 and 11,440 lbs. Viking’s 8-12 measured 41.4 feet in length and had a diameter of 45 inches. The average gross weight was 14,796 lbs.
The Viking rocket motor was a product of Reaction Motors Incorporated. It had a sea level thrust rating of 20,000 lbs. As was the case for the V2 rocket powerplant, the Viking’s propellants included alcohol (fuel) and liquid oxygen (oxidizer). Maximum demonstrated rocket motor burn time was 79 seconds for the Viking 1-7 series and 103 seconds for Vikings 8-12. The latter was longer due to the type’s larger propellant capacity.
The Viking’s nominal launch site was White Sands Proving Ground (WSPG) in New Mexico. However, early in the program, the Navy showed great interest in launching the vehicle from a ship at sea. The Navy’s biggest selling point for a shipboard launch was that researchers could choose their launch site. While the service had launched a V-2 from the deck of the USS Midway in 1947, the vehicle went into the drink shortly after lift-off when its control system failed. They hoped to do much better with the Viking.
Project Reach was the official name given to the Navy’s effort to conduct a shipboard launch of a Viking rocket. The USS Norton Sound, a ship that would figure prominently in the history of missile and space testing, was selected as the launch platform. The launch point chosen was the intersection of the Earth’s geographic and geomagnetic equators located near Christmas Island in the Pacific Ocean. The primary payload was a cosmic ray experiment weighing 394 lbs.
Viking No. 4 lifted-off from the deck of the USS Norton Sound at 1608 hours local time on Thursday, 11 May 1950. The vehicle rose straight and true into the partly cloudy tropical sky. Following a 74-second burn and a 168-second coast, the vehicle achieved an apogee of 91.2 nautical miles; the highest a Viking rocket had flown up to that time. Viking No. 4 impacted the ocean within sight of the launch ship about 435 seconds (7.25 minutes) after lift-off. Impact was supersonic.
Viking No. 4 gave the cosmic ray experimenta package a good ride and the data harvest was plentiful. Shipboard launch operations were uneventful in the main and entirely successful. Indeed, the experimentalists, the NRL launch operations team, the USS Norton Sound crew and the United States Navy were pleased with the results of the flight of Viking No. 4. Project Reach was a resounding success.
The Viking Program resumed launches back at WSPG in November of 1950. On Monday, 24 May 1954, Viking 11 reached an altitude of 137 nautical miles. It would be the all-time highest Viking flight.
The rapid pace of space technology during the second half of the 20th century soon caused Viking to fade into history. However, multi-disciplined technology developed during the Viking Program would influence the design and function of numerous subsequent launch vehicles. Perhaps the most direct example being the Navy’s 3-stage Vanguard satellite launch vehicle.
Sixty-four years ago this month, a missile launched on a flight test out of White Sands Proving Ground strayed from the test range and impacted near Ciudad Juarez, Mexico. The non-fatal mishap was attributed to a breakdown in range safety protocol.
The V2 missile (Vengeance Weapon No. 2) was developed by Nazi Germany during World War II for the purpose of attacking Allied population centers. As such, it was the world’s first ballistic missile. History records that more than 3,100 V2’s were fired in anger, with London, England and Antwerp, Belgium being the prime targets. Approximately 7,200 people lost their lives in V2 attacks between September 1944 and March 1945.
The V2 as flown by the Third Reich measured 46 feet in length and had a maximum diameter of 5.4 feet. Launch weight was 28,000 lbs. The V2’s rocket motor produced a maximum thrust of about 60,000 lbs at sea level. Ethyl alcohol and liquid oxygen served as fuel and oxidizer, respectively. Approximately 19,000 pounds of propellants were consumed in 65 seconds of boost flight.
The V2’s payload was an explosive warhead weighing about 1,600 lbs. The fearsome missile’s kinematic performance was impressive for its time. Maximum velocity was around 5,200 ft/sec. After burnout, the rocket followed a ballistic flight path all the way to the target. Maximum altitude and range for wartime missions was on the order of 50 nm and 175 nm, respectively.
With the defeat of Nazi Germany, both the United States and the Soviet Union gained access to a large number of V2 missiles and many of the German rocket scientists who developed the weapon. The United States shipped 300 rail freight cars full of V2 missile components back home. Under Operation Paperclip, some 126 German engineering and scientific personnel were expatriated to the United States. Initially operating out of Fort Bliss, Texas and White Sands Proving Ground (WSPG), New Mexico, these men were destined to make major contributions to the American space program. Among their number was one Werhner von Braun.
Sixty-seven V2 missiles were launched from White Sands Proving Ground (WSPG) between 1946 and 1952. These flights gave the United States invaluable experience in all aspects of rocket assembly, handling, fueling, launching and tracking. Indeed, V2 rocket technology and lessons-learned were applied in the development of all subsequent American launch vehicles ranging from the Redstone to the Saturn V. WSPG V2’s were also used to conduct numerous high altitude and space research experiments. Many aerospace “firsts” were achieved along the way. The first biological space payloads, first photographs of earth from space and the first large two-stage rocket flights involved the former vengeance weapon.
Rocket system reliability was not particularly good in the 1940’s and 1950’s. For instance, only 68% of the WSPG V2 flights were considered successful. Range safety was in its infancy too. In particular, the comprehensive range safety protocol that governs flight operations at today’s test ranges did not yet exist. This state of affairs was largely due to the fact that much of the systems knowledge and operations lessons-learned required to establish such a protocol had yet to be acquired. An incident that occurred in May of 1947 serves to underscore the reliability and safety issues just noted.
The Hermes II missile (RTV-G-3/RV-A-3) was a derivative of the basic V2 vehicle. The payload was a forward-mounted, winged, ramjet engine testbed. The V2’s tail surfaces were enlarged to counter the destabilizing influence of the payload’s wing group. The idea was to get the payload up to a Mach number beyond 3 and separate it from the V2 booster. Following separation, the ramjet pack would be ignited and thrust established. The payload would then fly a programmed altitude-Mach number flight profile. While ambitious on several levels, the project was certainly emblematic of this era of aerospace history wherein all manner of ideas took to the skies.
On Thursday, 29 May 1947, Hermes II was fired from Launch Complex 33 at White Sands Proving Ground. It was approximately 1930 hours local time. It is noted that the ramjet pack was not active for this first flight. The Hermes test vehicle was supposed to pitch to the north and fly uprange. Instead, it pitched to the south and backrange toward El Paso, Texas. Post-flight analysis revealed that the new inertial guidance system employed by the Hermes missile had been wired backwards! This human error directly and adversely affected rocket system reliability.
The WSPG Range Safety Officer(RSO) had both the authority and responsibility to hit the destruct button once it was obvious that the Hermes II was errant. However, a project scientist physically restrained the RSO from doing so! Apparently, the scientist was of the (evidently strong) opinion that the test vehicle’s propellant load should not be wasted on such trivial grounds as the safety of the El Paso populace. Unimpeded now, the errant rocket continued its flight. Range safety protocol would have to be improved and understood by all participants prior to the next flight!
The Hermes II reached a maximum altitude of 35 nm on its unplanned trip to the south. During its 5 -minute flight, the vehicle overflew the city of El Paso and impacted near the Tepeyac Cemetary located 3.5 miles south of Ciudad Juarez, Mexico. The quasi-Mach 1 impact formed a crater that measured 50 feet in width and 24 feet in depth. Enterprising local residents gathered what little airframe wreckage that survived impact and sold it to souvenir seekers!
United States Army authorities quickly arrived on scene to ascertain the extent of the damage caused by the errant missile’s unannounced and unwelcome arrival. Happily, no lives were lost. Profuse apologies were delivered to and graciously accepted by Mexican government officials. The United States paid for all damages and effected a complete clean-up and remediation of the impact site.
A member of the team of expatriated German scientists who conducted the Hermes II flight test later was quoted as saying: “We were the first German unit to not only infiltrate the United States, but to attack Mexico from US soil!” Not nearly so amused, the Army tightened-up range safety protocol at WSPG in the aftermath of the international incident. Interestingly, historical evidence points to the likelihood that the Hermes II vehicle never did carry an active ramjet payload on test flights out of WSPG.
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.
