According to the FAI (Fédération Aéronautique Internationale) which maintains records for aeronautical activities, the “official” threshold of space is at an altitude of 100 kilometers which corresponds to the Karman Line – the altitude where the air becomes so thin that an aircraft would need to exceed orbital velocity in order to support itself by aerodynamic lift alone. Today there are a number of companies developing reusable spacecraft to fly suborbital flights that will cross over this boundary to provide paying passengers a brief taste of weightless conditions and qualify them to be astronauts. But these efforts are only the latest in a long history of suborbital crewed spaceflights which stretch back to the earliest years of the Space Age. What follows is a history of the eight flights to date which qualify as suborbital crewed spaceflights.

Mercury-Redstone Flights of 1961

The first suborbital crewed spaceflights are also probably the best known: NASA’s Mercury-Redstone flights which launched the first Americans into space. The purpose of these suborbital missions was to send the Mercury spacecraft on a brief 15-minute test flight to assess the spacecraft and the ability of the pilot to operate during the various phases of spaceflight especially weightlessness whose effects on humans were largely speculative before these missions. These brief flights, which used a modified Redstone missile developed by a team under Wernher von Braun for the US Army (see “Redstone: The Missile That Launched America into Space”), would be followed by longer orbital flights launched using a modified Atlas D missile.

The first test flight of the Mercury-Redstone, designate MR-1, took place on November 21, 1960. Unfortunately the rocket only rose about ten centimeters or so off the launch pad before the engine cut out. After the rocket settled back onto the pad (and did not explode!), Mercury’s launch abort system activated, sending the escape tower off towards the Atlantic but leaving the Mercury capsule behind. The problems uncovered by this test were corrected and a new Redstone launched MR-1A on December 19. A second test flight, MR-2 carrying a chimpanzee named Ham, was launched on January 31, 1961. Unfortunately a number of problems occurred during this flight, which resulted in the MR-2 capsule overshooting its intended landing zone by 212 kilometers. After these problems were corrected, one last test flight with a boilerplate Mercury capsule, designated MR-BD, was successfully launched on March 24, clearing the way for the first manned Mercury flights. Unfortunately the delay also gave the Soviet Union the opportunity to beat the US in space once again with the launch of Vostok carrying cosmonaut Yuri Gagarin on April 12, 1961 to become the first person to fly into space.

The first manned flight of the Mercury, MR-3, used the 1,290-kilogram Mercury spacecraft number 7 nicknamed Freedom 7 which was delivered to Cape Canaveral, Florida on December 9, 1960. The Redstone MRLV (Mercury Redstone Launch Vehicle) for this mission, designated MR-7, arrived at the Cape in late March as a replacement to MR-3 which was originally meant for the first manned Mercury flight but was used in the MR-1A test flight instead. The pilot for this mission was Alan Shepard with John Glenn and Virgil “Gus” Grissom serving as his backups (see “Project Mercury: Choosing the Astronauts & Their Machine“).

The first launch attempt for the MR-3 mission on May 2 was canceled 2 hour and 20 minutes before the scheduled liftoff due to weather problems. The rescheduled May 4 launch date was subsequently pushed back to May 5 at 7:20 AM EST again because of weather issues. After eating what would soon become a traditional launch day breakfast of steak and eggs, Alan Shepard suited up and was strapped into Freedom 7 at 5:15 AM on May 5. After enduring over two hours of unscheduled countdown holds for weather and minor equipment issues, MR-3 finally lifted off from Launch Complex 5 at 9:34:13 AM EST and headed out over the Atlantic.

The Redstone booster operated as intended shutting down after a burn of two minutes and 22 seconds with Freedom 7 travelling at an inertial velocity of 2,296 meters per second. After his spacecraft had separated from the Redstone, Shepard then proceeded to change the spacecraft attitude in a planned series of manual and automatic maneuvers testing various modes of key systems in the process. After reaching a peak altitude of 187.5 kilometers five minutes after launch, Shepard fired the retrorocket package and jettisoned it to test this system for future orbital flights. After reaching a peak load of 11.6 g during reentry, Freedom 7 deployed its parachutes and landed in the Atlantic Ocean 487.3 kilometers downrange some 15 minutes and 28 seconds after launch. Shepard and his Freedom 7 capsule were recovered shortly after splashdown by the Essex-class aircraft carrier, the USS Lake Champlain. The mission was deemed a complete success.

The next test flight of the Mercury program, MR-4, was flown by Gus Grissom with John Glenn serving as his backup. This flight, which would be a repeat of the MR-3 mission, would use the 1,286-kilogram Mercury spacecraft number 11 and Redstone MRLV number MR-8. The Mercury capsule, nicknamed Liberty Bell 7, incorporated a number of design changes compared to Shepard’s Freedom 7 including a new trapezoidal window in front of the pilot which replaced the pair of small 25-centimeter portholes on the earlier capsules and a new hatch design which incorporated an explosive emergency release feature.

The launch of MR-4 was originally scheduled for July 16, 1961 but it was postponed to July 18 due to weather. Weather forced another delay to July 19 which was again scrubbed due to weather issues with just ten and a half minutes to go until launch. Liberty Bell 7 with Grissom on board was finally launched from LC-5 at 7:20:36 AM EST on July 21. Once again, the Redstone performed as intended shutting down two minutes and 22 seconds after launch with the spacecraft travelling at 1,969 meters per second relative to the Earth below.

After separating his spacecraft from the Redstone booster, Grissom then set about his tightly scheduled sequence of tasks to check out the Mercury capsule in preparation for future orbital missions. After reaching a peak altitude of 190.3 kilometers, Grissom fired and then jettisoned his retrorockets in preparation for reentry. Reentry and landing went as planned with splashdown taking place 486.2 kilometers downrange in the Atlantic Ocean after a flight lasting 15 minutes and 37 seconds. With Grissom preparing for recovery as helicopters from the USS Randolph approached, the explosive hatch blew off unexpectedly allowing seawater to rush into the capsule. Grissom quickly exited the sinking Liberty Bell 7 as recovery crews attempted to save the sinking capsule. Too heavy to lift with the growing load of water inside, the recovery crews were forced to cut the capsule loose and allow it to sink to the ocean floor. Grissom was then plucked out of the Atlantic and taken to the USS Randolph.

Although there was disagreement about the cause of the premature activation of the explosive hatch, the flight of Liberty Bell 7 was considered to be a success despite the loss of the spacecraft. With all of the objectives of the suborbital test flight program met, further Mercury-Redstone missions were cancelled and all effort turned to the first Mercury-Atlas orbital mission. It was not until July 20, 1999 that Liberty Bell 7 was recovered in 4,600 meters of water by a team led by Curt Newport and financed by the Discovery Channel. Gus Grissom would go on to fly as the command pilot with John Young as his pilot on the Gemini 3 mission in March 1965 (see “The Mission of Gemini 3”). Grissom would tragically die during the Apollo 1 pad fire on January 27, 1967 (see “The Future That Never Came: The Unflown Mission of Apollo 1“). Alan Shepard, who was grounded for five years with an inner ear disorder after the Mercury program, would go on to command the Apollo 14 mission in 1971 to become the only member of the original “Mercury 7” astronaut team to walk on the Moon.

X-15 Spaceflights of 1963

Unlike the first two, the next pair of suborbital crewed spaceflights received almost no public attention coming in the wake of the last Mercury orbital mission in May 1963. But unlike the ballistic Mercury-Redstone flights where the astronaut was essentially a passenger, these next suborbital spaceflights would use the famous X-15 rocket plane with a pilot taking active control of all aspects of the flight.

The 15,200-kilogram X-15 was part of an experimental hypersonic rocket plane program run by the USAF and NASA to fly as fast as Mach 6 and at peak altitudes of at least 76 kilometers (see “The First Reusable Spacecraft: The Origins & First Test Flights of the X-15“). Started in 1954, this program would expand the performance envelope explored by the first generation of rocket planes like the X-1 series and penetrate the threshold of space in preparation of future programs like the X-20 Dyna Soar which would push performance limits to even higher speed and altitudes (see “The Future That Never Came: The X-20 Dyna Soar Aerospace Plane”). The first X-15, X-15-1 fitted with a pair of 27-kilonewton XLR-11 engines as an interim power plant, was rolled out on October 15, 1958 and made its first unpowered glide flight after being dropped from its NB-52 carrier aircraft on June 8, 1959 eventually followed by the first powered flight using the second X-15 on September 17. X-15-2 made the first powered flight using the 250-kilonewton XLR-99 engine on November 15, 1960 with the third aircraft, X-15-3, making its inaugural flight on December 20, 1961 with NASA civilian pilot, Neil Armstrong, at the controls.

During the first few years of operation, the performance envelope of the X-15 was slowly expanded to ever higher speeds and altitudes. During Flight 52 of the X-15 program on April 30, 1962, NASA test pilot Joseph Walker flew X-15-1 to an altitude of 75.1 kilometers achieving the aircraft’s original design goal. During Flight 63 on July 17, USAF test pilot Robert White flew X-15-3 to a then record-setting altitude of 95.9 kilometers. Since the flight exceeded the USAF threshold of 50 miles or 80.5 kilometers for space (but is below the 100-kilometer Karman line widely recognized today), White qualified for his USAF astronaut wings on this flight. Joe Walker was similarly qualified during Flight 77 on January 17, 1963 when he flew X-15-3 to an altitude of 82.8 kilometers. During Flight 87 on June 27, USAF test pilot Robert Rushworth flew X-15-3 to an altitude of 86.7 kilometers qualifying for his astronaut wings.

While these series of flights were higher than the design goal of the X-15, it was still well below what this aircraft was actually capable of doing. Theoretically, the X-15 could fly to altitudes in excess of 122 kilometers and safely return if everything went precisely as planned. To test the X-15 to its limits yet leave some margin for safety due to unavoidable deviations in pilot and hardware performance, it was decided to fly X-15-3 in two successive flights to build up from the then current experience up to an altitude of 110 kilometers –above the 100-kilometer Karman line but still safely below the limits of the X-15.

Joe Walker was chosen to pilot the two high altitude X-15 missions designated Flights 90 and 91. For Flight 90, Walker was to burn the XLR-99 engine for 83 seconds to achieve a peak speed of Mach 5.40 and an altitude of 96.0 kilometers approximately equaling Bob White’s record set a year earlier. During the flight, Walker would deploy a balloon on the end of a line to measure air density while other experiments were performed with a ultraviolet photometer used to measure Earth backgrounds and an infrared photometer to measure the craft’s exhaust signature.

NB-52B number 8, nicknamed “The Challenger”, took off at 9:20 AM PST on July 19, 1963 with X-15-3 under its starboard wing and Walker onboard for Flight 90. At 10:20:05, X-15-3 was dropped while over a location known as Smith Ranch and Walker quickly brought the XLR-99 engine up to full power. The XLR-99 burned for a total of 84.6 seconds and hit a peak speed of 1,658 meters per second or Mach 5.50. The slightly longer burn of the XLR-99 engine in conjunction with slightly higher than expected thrust as well as a 0.5° error in climb angle combined so that X-15-3 overflew its intended peak altitude and reached a record setting 106.0 kilometers – ten kilometers higher than planned and the first flight of a winged craft above the Karman line. Walker successfully piloted the X-15 through reentry and safely landed on Rogers Dry Lake at Edwards Air Force Base after a flight of 11 minutes and 24 seconds. The only notable failure was an instrumentation malfunction in the balloon experiment.

With this success under their belts, the X-15 team prepared for a second flight to test the limits of the aircraft’s design with a flight to 110 kilometers. It was planned that the XLR-99 engine would burn for 84.5 seconds to reach a top speed of Mach 5.38. For this flight, an experiment to observe the exhaust plume in the ultraviolet was carried. Over the course of two weeks, three launch attempts were aborted. On August 3, 1963 the flight was called off due to the weather as “The Challenger” was climbing to its launch point. A week later, problems with the APU #1 (Auxiliary Power Unit) on the X-15 forced a scrub. On August 15, more APU and weather issues along with a radio problem ended the third launch attempt.

Finally, on August 22, 1963 at 9:09 PST NB-52A number 003 lifted off with X-15-3 for the fourth launch attempt of Flight 91. At 10:05:57 PST, X-15-3 was dropped over Smith Ranch for the start of its record setting flight. Walker used a newly installed altitude predictor in his instrument panel to adjust his climb angle so that he would hit his target altitude. When the XLR-99 shutdown as it exhausted its propellants after a burn of 85.8 seconds, X-15-3 was passing through an altitude of 53.6 kilometers and travelling at 1,695 meters per second or Mach 5.58 – a touch faster than planned. After climbing for almost two more minutes, X-15-3 with Walker at the controls hit a record setting altitude of 107.96 kilometers – just two kilometers shy of the goal but sufficient to meet the mission objectives. The only other issue encountered during the flight was a frozen left roll thruster controlled from the X-15’s side control stick.

Walker successfully piloted the X-15 through reentry and a touchdown on Rogers Dry Lake. He had covered 491 kilometers across the ground from the drop point over Smith Ranch to landing in 11 minutes and 8.6 seconds of flight. With this flight, Joe Walker became the first person to fly into space twice and the X-15-3 became the first craft to do the same. With this flight completed, Joe Walker left the X-15 program to work on other projects including the initial test flights of Lunar Landing Research Vehicle (LLRV) used by NASA astronauts to practice lunar landings. Walker tragically died on June 8, 1966 when his F-104 chase aircraft collided with a XB-70 Valkyrie bomber during a tight formation publicity photo shoot.

The X-15 program would continue for another five years after Walker’s record-breaking mission making an additional 108 flights. While the X-15 would never fly above the Karman line again, it did make another eight flights which qualified five more pilots for their astronaut wings. Unfortunately, X-15-3 and its pilot were lost on one of these missions. On Flight 191 flown on November 15, 1967, USAF test pilot Michael Adams died when X-15-3 broke up during a botched reentry because of an instrumentation malfunction while descending from a peak altitude of 81.1 kilometers. The USAF awarded Adams his astronaut wings posthumously after the only fatal accident in the otherwise highly successful, decade-long X-15 flight program.

The “April 5 Anomaly” of 1975

The next suborbital crewed spaceflight would not take place for almost a dozen years – and it was not originally planned to be a suborbital flight at all. Instead, it involved the first ever in-flight launch abort of a crewed spaceflight on April 5, 1975 of what was supposed to be the Soviet Union’s “Soyuz 18” mission (see “Soyuz 18A: The First Crewed Inflight Launch Abort“). The crew for this flight consisted of veteran cosmonauts Vasili Lazarev as the commander and Oleg Makarov as the flight engineer.

These two cosmonauts had flown together earlier on Soyuz 12 launched on September 27, 1973. The purpose of the Soyuz 12 mission was to perform a two-day orbital flight test of the upgraded Soyuz 7K-T ferry (an ancestor of the Soyuz TMA-M spacecraft still flown today by Russia) to check out the modifications made after the loss of three cosmonauts at the end of the Soyuz 11 mission to the Soviet Union’s first space station, Salyut 1, in June 1971. The mission for this new flight with Lazarev and Makarov, using the call sign “Urals”, was to spend 60 days onboard the Salyut 4 space station which had been launched into orbit the previous December and had hosted the crew of Soyuz 17 for a 28-day mission. The intent was to have the crew back on Earth before the launch of the upcoming Apollo-Soyuz Test Project (ASTP) mission in July.

The Soyuz 7K-T number 39 atop its Soyuz 11A511 launch vehicle serial number Kh15000-023 lifted off from Launch Complex 1 at the Baikonur Cosomodrome (the same pad used by Yuri Gagarin in 1961) at 14:04:54 Moscow Time on April 5, 1975. At 120 seconds after launch, the four tapered boosters of the Soyuz rocket were dropped as planned from the Blok A core followed 30 seconds later by the jettisoning of the LES which was no longer needed to support abort options for the rest of the flight. Unknown to all at the time, excessive vibration during the ascent of the Soyuz rocket had caused an electrical relay to close unexpectedly which prematurely detonated one of two sets of pyrotechnic charges that were used to split apart the lattice structure that held the Blok I upper stage to the Blok A core stage during ascent. This premature firing also severed the electrical connections to the remaining charges needed to fully separate the two stages.

At 288 seconds after launch, the Blok A core shut down as planned. The Blok I upper stage was then suppose to separate and ignite sending the Soyuz into orbit. Instead, the Blok I failed to fully separate from the Blok A core as its RD-461 engine ignited. The ascending craft began to roll and pitch heavily followed by a “Booster Failure” alarm sounding in the Soyuz cockpit and the emergency shutdown of the RD-461 engine when the attitude had deviated by more than the preset limit of 10 degrees only four seconds after ignition.

With the automatic abort system triggered at an altitude of 145 kilometers (already above the 100-kilometer Karman line), the Soyuz’s descent/orbital modules separated from the now inert launch vehicle followed by jettisoning the orbital module in preparation for an emergency descent. After reaching a peak altitude of 192 kilometers and the crew experiencing about 400 seconds of weightlessness, the Soyuz automatically executed a high-g ballistic reentry with a peak braking load of 21.3 g instead of the normal 3 to 4 g owing to a flight path that was steeper than a normal descent from orbit. The Soyuz descent module came down in the Altai Mountains 1,574 kilometers downrange after a flight of 21 minutes and 27 seconds.

The landing site of what became popularly known in the West as “Soyuz 18A”, a mountain called Teremok-3, was covered in chest-deep powdery snow at the time of landing. The descent module came to a stop just 150 meters shy of a sheer drop after rolling down the mountain’s steep slope before its parachute lines had become entangled in some vegetation. The cosmonauts donned their cold-weather survival gear and exited the capsule to wait for rescue teams to reach them. After much difficulty dealing with the mountainous terrain, the cosmonauts were rescued following a night spent on the mountain.

On April 7, after the cosmonauts had returned home and been checked out, Soviet officials broke the news of the launch abort which they simply called the “April 5 anomaly”. Naturally, the American partners of the upcoming ASTP mission were interested in the cause of the mishap and required an explanation. Soviet officials provided the results of their investigation and assured the Americans that the upcoming ASTP mission (as well as subsequent manned Soyuz missions for the next 27 years) would use the newer Soyuz-U 11A511U launch vehicle which had a different separation system design that could not suffer from the same sort of malfunction that affected Soyuz 18A. On May 24, 1975 another Soyuz was successfully launched to Salyut 4 to become “Soyuz 18” with Pyotr Klimuk and Vitali Sevastyanov as the new crew. As for the crew of the aborted mission, Makarov went on to fly on the Soyuz 27 and T-3 missions to Salyut 6 in 1977 and 1980, respectively. Reports indicate that Lazarev apparently had experienced internal injuries during the high-g emergency descent and he never returned to flight status.

The SpaceShipOne Flights of 2004

After the “April 5 anomaly”, it would be 29 years before another suborbital crewed spaceflight would be made. But unlike the earlier flights which were part of government programs, this new series was made as part of a private venture using an innovative craft called SpaceShipOne in an attempt to win the Ansari X Prize – a $10 million cash prize created by the X Prize Foundation in May 1996 to be given to the first non-government organization to fly a reusable crewed spacecraft into space twice within a period of two weeks.

SpaceShipOne was developed by a joint venture between Burt Rutan’s Scaled Composites (which had previously developed a number of highly innovative aircraft over the years) and American business man Paul Allen known as Mojave Aerospace Ventures. Also known as Scaled Composites Model 316 and developed for that company’s Tier One program, the 3,600-kilogram SpaceShipOne was designed to carry a pilot and up to two passengers to an altitude of up to 112 kilometers. After being dropped at an altitude of about 15 kilometers from its specially built Model 318 carrier aircraft known as White Knight, SpaceShipOne would climb steeply under the power of a 88-kilonewton hybrid rocket motor supplied by SpaceDev which used solid HTPB as a fuel and liquid nitrous oxide as an oxidizer. This hybrid rocket motor could burn for up to 87 seconds but, unlike conventional solid rockets, could be shut down at any point by cutting off the oxidizer supply to meet mission requirements or abort its flight if necessary.

After reaching apogee, SpaceShipOne would use a unique feathering reentry system where the rear half of its wing along with its twin tail booms would pivot upward on a hinge to provide an aerodynamically stable configuration. This high-drag mode used during its steep descent limited heating during reentry where deceleration loads reached as high as 5 g. Once the craft had descended to an altitude of 10 to 20 kilometers, the wing on SpaceShipOne moved back into its low-drag configuration so that it could glide to a landing on a runway about 20 minutes or so after its launch.

SpaceShipOne made its first captive test flight, designated Flight 01C, attached to White Knight on May 20, 2003 with nobody aboard. Its first glide flight, 03G, was made on August 7 with test pilot Mike Melvill at the controls. Flight 11P with test pilot Brian Binnie was the first powered flight on December 17 (the centennial of the Wright brothers’ first powered flight) reaching a peak speed and altitude of Mach 1.2 and 20.7 kilometers, respectively, during an 18-minute flight. During the spring of 2004, SpaceShipOne made a series of three additional test flights to higher speeds and altitudes in preparation for its first spaceflight.

Based on the confidence built up from the series of test flights and with the receipt of a one-year license for suborbital rocket flights issued on April 1, 2004 from the US Office of Commercial Space Transport, SpaceShipOne was ready to attempt its first spaceflight with a planned apogee of 110 kilometers. Flight 15P started at 6:47 AM PDT on June 21, 2004 with the takeoff of White Knight from the Mojave Spaceport in California just four days after it had received its official FAA certification as a spaceport.

With Mike Melvill at the controls, SpaceShipOne was released from White Knight at 7:50 AM at an altitude of 14.3 kilometers. Melvill immediately ignited the rocket motor and SpaceShipOne started its climb. While there were some issues controlling the craft’s attitude during the climb, the rocket motor shutdown after a 76-second burn at an altitude of 54.9 kilometers with the speed at 961 meters per second. At Mach 2.9, this was already the fastest a civilian aircraft had ever flown. Because of the attitude issues during the climb, SpaceShipOne reached a peak altitude of only 100.1 kilometers – lower than planned but still just above the 100-kilometer Karman line making this the first ever civilian spaceflight. After experiencing about 3½ minutes of weightlessness, Melvill reentered the atmosphere and successfully landed SpaceShipOne at the Mojave Spaceport in front of a crowd of 11,000 people gathered to witness the historic flight which lasted 24 minutes and five seconds.

After the issues with Flight 15P were analyzed over the next two weeks, it was decided that another test flight was not needed and all efforts turned towards flying the pair of flights required to win the Ansari X Prize. After delays due to early morning winds, Flight 16P got underway with the take off of White Knight at 7:11 AM PDT on September 29, 2004 with Mike Melvill once again at the controls of SpaceShipOne. At 8:09 AM, SpaceShipOne was released and ignited its rocket motor six seconds later. Some 50 seconds into the powered ascent, SpaceShipOne began to roll as it surpassed Mach 2.7 but given the high altitude conditions, there was little aerodynamic stress on the craft so it was not a concern. Once instrumentation indicated the required altitude could be achieved, Melvill shut down the rocket motor after a burn of 76 seconds.

SpaceShipOne reached a peak altitude of 102.9 kilometers comfortably exceeding the Karman line and satisfying the Ansari X Prize requirements. Melvill was then able to damp out the unexpected roll using reaction jets and proceeded to perform his reentry and glide towards landing. Flight 16P ended with a successful landing at the Mojave Spaceport after a flight of 24 minutes and 11 seconds. SpaceShipOne had become the first civilian spacecraft to fly into space twice while Melvill became the first commercial astronaut to do the same. With this success under their belt, the team had just 14 days to repeat their feat to win the Ansari X-Prize.

Just five days after Flight 16P, SpaceShipOne was ready to fly Flight 17P this time with Brian Binnie at the controls. The flight began with the takeoff of White Knight at 6:49 AM PDT on October 4, 2004 – the 47th anniversary of the launching of Sputnik and the beginning of the Space Age. White Knight released SpaceShipOne at 7:49 AM at an altitude of 13.3 kilometers and Binnie promptly ignited the rocket motor. The climb was nearly perfect with SpaceShipOne hitting Mach 3.09 at burnout and reaching a peak altitude of 112.01 kilometers not only securing the Ansari X-Prize but also breaking the rocket plane altitude record of 107.96 kilometers set 41 years earlier by Joe Walker flying the X-15-3. Binnie successfully landed SpaceShipOne at the Mojave Spaceport at 8:13 AM after a flight of 23 minutes 56 seconds.

A fourth spaceflight using SpaceShipOne that was scheduled for October 13, 2004 was cancelled as were all future flights so as not to risk damaging the historic (and unique) SpaceShipOne. On October 5, 2005 SpaceShipOne was placed on display in the National Air and Space Museum in Washington, DC. Based on the experience with SpaceShipOne, Burt Rutan teamed up with Sir Richard Branson to form Virgin Galactic which is developing the suborbital SpaceShipTwo for space tourists. In 2014 Brian Binnie became a senior engineer and test pilot for XCOR Aerospace whose projects include developing the Lynx suborbital space plane for space tourists. Considering the progress these and other companies are making, it will not be long before the next suborbital crewed spaceflight is made and eventually become routine.

Follow Drew Ex Machina on Facebook.

Related Videos

Here is an excellent NASA documentary from 1961 on the Freedom 7 mission.

﻿

Here is another excellent period documentary from NASA entitled “Research Project X-15” which goes into the development and early flights of the X-15 program.

﻿

And finally, here is a long documentary produced by the Discovery Channel on the development and flights of SpaceShipOne entitled “Black Sky: The Race for Space”.

﻿

Related Reading

“Soyuz 18A: The First Crewed Inflight Launch Abort”, Drew Ex Machina, April 5, 2019 [Post]

“Redstone: The Missile That Launched America into Space”, Drew Ex Machina, April 26, 2016 [Post]

“The First Reusable Spacecraft: The Origins and the First Test Flights of the X-15”, Drew Ex Machina, May 10, 2019 [Post]

General References

David Baker, The History of Manned Space Flight, Crown Publishers, 1981

Phillip Clark, The Soviet Manned Space Program, Orion Books, 1988

Edward Clinton Ezell and Linda Neuman Ezell, The Partnership: A NASA History of the Apollo-Soyuz Test Project, Dover Publications, 2010

Rex D. Hall and David J. Shayler, Soyuz: A Universal Spacecraft, Springer-Praxis, 2003

Dennis R. Jenkins and Tony R. Landis, Hypersonic: The Story of the North American X-15, Specialty Press, 2003

Loyd S. Swenson, Jr., James M. Grimwood and Charles C. Alexander, The New Ocean: A History of Project Mercury, SP-4201, NASA History Division, 1998

Milton O. Thompson, At The Edge of Space: The X-15 Flight Program, Smithsonian Institution Press, 1992