- Parabolic Arc
- September 21, 2023
Virgin Galactic Pilots Join 80.46-Kilometer (50-Mile) Club
by Douglas Messier
Virgin Galactic pilots Mark “Forger” Stucky and Frederick “C.J.” Sturckow, who were awarded civilian astronaut wings last week, are among 18 pilots who have flown suborbital flights.
The two pilots flew SpaceShipTwo Unity to an altitude of 51.4 miles (82.72 km) on Dec. 13, 2018. That accomplishment qualified them for civilian astronaut wings using an American definition that places the boundary of space at 50 miles (80.46 km).
Of the 21 suborbital flights flown since 1961, 17 involved winged suborbital vehicles dropped from mother ships over the Mojave Desert. Two launches were planned suborbital missions from Cape Canaveral in Florida. Two other suborbital flights involved Soyuz orbital launches from Baikonur in Kazakhstan that suffered in-flight aborts.
|Mercury-Redstone 3 (Freedom 7)||May 5, 1961||5,134 mph (8,262 km/h)||115 miles
|Alan B. Shepard (NASA)|
|Mercury-Redstone 4 (Liberty Bell 7)||July 21, 1961||5,200 mph
|118.26 miles (190.3 km)||Virgil I. “Gus” Grissom (NASA)|
|X-15 Flight 62||July 17, 1962||3,831 mph (6,165 km/h)||59.6 miles (95.9 km)||Robert M. White (USAF)|
|X-15 Flight 77||January 17, 1963||3,677 mph (5,918 km/h)||51.4 miles (82.7 km)||Joseph A. Walker (NASA)|
|X-15 Flight 87||June 27, 1963||3,425 mph (5,512 km/h)||53.9 miles (86.7 km)||Robert A. Rushworth (USAF)|
|X-15 Flight 90||July 19, 1963||3,710 mph (5,971 km/h)||65.8 miles (105.9 km)||Joseph A. Walker (NASA)|
|X-15 Flight 91||August 22, 1963||3,794 mph (6,106 km/h)||67.0 miles (107.8 km)||Joseph A. Walker (NASA)|
|X-15 Flight 138||June 29, 1965||3,431 mph (5,522 km/h)||53.1 miles (85.5 km)||Joe H. Engle (USAF)|
|X-15 Flight 143||August 10, 1965||3,549 mph (5,712 km/h)||51.3 miles (82.6 km)||Joe H. Engle (USAF)|
|X-15 Flight 150||September 28, 1965||3,731 mph (6,004 km/h)||55.9 miles (90.0 km)||John B. McKay (NASA)|
|X-15 Flight 153||October 14, 1965||3,554 mph (5,720 km/h)||50.4 miles (81.1 km)||Joe H. Engle (USAF)|
|X-15 Flight 174||November 1, 1966||3,750 mph (6,035 km/h)||58.1 miles (93.5 km)||William H. “Bill” Dana (NASA)|
|X-15 Flight 190||October 17, 1967||4,519 mph (7,273 km/h)||53.1 miles (85.5 km)||William J. “Pete” Knight (USAF)|
|X-15 Flight 191||November 15, 1967||3,569 mph (5,744 km/h)||50.3 miles (81.0 km)||Michael J. Adams (USAF)|
|X-15 Flight 197||August 21, 1968||3,443 mph (5,541 km/h)||50.6 miles (81.4 km)||William H. “Bill” Dana (NASA)|
|Soyuz 7K-T No. 39 (Soyuz 18a)||April 5, 1975||?||119 miles
|Vasily Lazarev, Oleg Makarov (Soviet Union)|
|SpaceShipOne Flight 15P||June 21, 2004||2,150 mph (3,460 k/ph)||62.2 miles (100.1 km)||Mike Melvill (Scaled Composites)|
|SpaceShipOne Flight 16P||September 29, 2004||2,110 mph (3,396 k/ph)||63.96 miles (102.9 km)||Mike Melvill (Scaled Composites)|
|SpaceShipOne Flight 17P||October 4, 2004||2,186 mph (3,518 k/ph)||69.6 miles (112 km)||Brian Binnie (Scaled Composites)|
|Soyuz MS-10||October 11, 2018||?||58 miles
|Aleksey Ovchinin (Roscosmos), Nick Hague (NASA)|
|SpaceShipTwo Unity PF04||December 13, 2018||Mach 2.9||51.4 miles
|Mark “Forger” Stucky, Frederick “C.J.” Sturckow (Virgin Galactic)|
NASA got suborbital spaceflight started in 1961 with a pair of Mercury-Redstone flights flown by Alan Shepard and Gus Grissom. Both astronauts flew well above the 100-km (62.1-mile) boundary that the Fédération Aéronautique Internationale (FAI), which keeps aviation and space records, recognizes as the boundary of space.
As the Mercury program transitioned to orbital missions, suborbital flights shifted over to the X-15 program based out of Edwards Air Force Base in California. Five military and three civilian pilots made 13 flights above 50 miles (80.46 km) between 1962 and 1968.
The U.S. Air Force awarded astronaut wings to five pilots — Robert M. White, Robert A. Rushworth, Joe H. Engle, William J. “Pete” Knight and Michael J. Adams – who flew above 50 miles.
Adams’ recognition was posthumous as he died when his X-15 crashed in November 1967 on the 191st flight of the program. It was the only in-flight fatality of the program.
Civilian Joseph A. Walker was the only pilot to fly above 100 km (62.1 miles), which he accomplished twice in 1963. However, NASA did not recognize him or the other two NASA pilots who flew above 50 miles — William H. Dana and John B. McKay — as astronauts until 2005. That recognition came in the wake of three SpaceShipOne suborbital flights by Scaled Composites.
By that time, both Walker and McKay were dead. Walker died in June 1966 when his fighter collided with an XB-70 Valkerie bomber during a publicity shoot over the Mojave Desert. Both aircraft crashed; XB-70 co-pilot Carl Cross died but pilot Al White survived with injuries.
McKay died in 1975 at the age of 52. Injuries he sustained during the crash of an X-15 in 1962 were a major contributing factor to his early death.
|Suborbital Flights by Pilots & Maximum Altitude|
|Reusable Winged Vehicles
|Flights Above 100 Km||Maximum Altitude|
| Brian Binnie
|SpaceShipOne||0||1|| 69.6 miles
|Joseph A. Walker (NASA)||X-15||1||2||67.0 miles (107.8 km)|
|Robert M. White (USAF)||X-15||1||0||59.6 miles (95.9 km)|
|William H. “Bill” Dana (NASA)||X-15||2||0||58.1 miles (93.5 km)|
|John B. McKay (NASA)||X-15||1||0||55.9 miles (90.0 km)|
|Robert A. Rushworth (USAF)||x-15||1||0||53.9 miles (86.7 km)|
|Joe H. Engle (USAF)||x-15||3||0||53.1 miles (85.5 km)|
|William J. “Pete” Knight (USAF)||x-15||1||0||53.1 miles (85.5 km)|
|Mark “Forger” Stucky
|SpaceShipTwo||1||0|| 51.4 miles
|Frederick “C.J.” Sturckow (Virgin Galactic)||SpaceShipTwo||1||0|| 51.4 miles
|Michael J. Adams (USAF)||X-15||1||0||50.3 miles (81.0 km)|
|Expendable Ballistic Vehicles
|Flights Above 100 Km||Maximum Altitude|
|Soyuz 7K-T No. 39 (Soyuz 18a)||0||1||119 miles
|Soyuz 7K-T No. 39 (Soyuz 18a)||0||1||119 miles
|Virgil I. “Gus” Grissom (NASA)||Mercury-Redstone 4 (Liberty Bell 7)||0||1||118.26 miles (190.3 km)|
|Alan B. Shepard (NASA)||Mercury-Redstone 3 (Freedom 7)||0||1|| 115 miles
|Aleksey Ovchinin (Roscosmos)||Soyuz MS-10||1||0||58 miles
|Nick Hague (NASA)||Soyuz MS-10||1||0||58 miles
Engle, who flew the X-15 above 50 miles three times, became the first person to fly two different winged vehicles back from space when he piloted space shuttle Columbia back from orbit in November 1981.
Knight holds the X-15 speed record after flying the rocket plane to Mach 6.7 (4,519 mph or 7,274 km/h) on the program’s 190th flight in October 1967. He was the father of Steve Knight, who represented California’s 25th District in t he U.S. House of Representatives from 2015 to 2019.
Wings to Space, Revived
The X-15 program ended in December 1968 after 199 flights. Scaled Composites Founder Burt Rutan, who worked at Edwards Air Force Base during the program, revived the concept of air-dropped suborbital flights in the early 2000’s with his SpaceShipOne program.
SpaceShipOne was Rutan’s entry in the Ansari X Prize competition, which offered $10 million for the first privately built spacecraft to make two suborbital flights above 100 km within two weeks. Rutan and his Scaled Composites team was backed by Microsoft co-founder Paul Allen, who put $28 million into the program.
After conducting three powered flights to lower altitudes, Rutan and his team were ready to attempt a spaceflight on June 21, 2004. After SpaceShipOne was dropped from its White Knight mother ship, Mike Melvill fired the vehicle’s hybrid nitrous oxide-rubber engine for 76 seconds and reached a speed of Mach 2.9 Mach and an altitude of 328,491 feet – just barely above the FAI’s 100-km (328,084 ft) boundary of space recognized by the FAI.
Three months later on Sept. 29, Melvill was once again in the cockpit to conduct the first of the two flights for the Ansari X Prize. After firing the spacecraft’s engine, SpaceShipOne rolled 29 times before Melvill was able to bring the ship under control. The 77-second engine boosted SpaceShipOne to a speed of more than Mach 2.92 and an apogee of 337,700 feet (103 km/63.96 miles).
Five days later, Brinnie Binnie broke the altitude record that Joseph Walker had set 41 years earlier in the X-15 by flying SpaceShipOne to an altitude 367,500 feet (112 km/69.6 miles).
The two flights won the Ansari X Prize for Allen, Rutan and the Scaled team that worked on the project. Melvill and Binnie also became the first two private pilots to win civilian astronaut wings for three flights.
SpaceShipOne was retired after the flight and donated to the Smithsonian Institution for display in the National Air and Space Museum in Washington, D.C.
Binnie’s flight was the last crewed suborbital flight by a winged vehicle until Stucky and Sturckow flew Unity above 50 miles on Dec. 13. As a former NASA astronaut who flew the space shuttle, Sturckow had already been awarded astronaut wings by NASA. It was the first flight above 50 miles for Stucky.
The Ooops! Suborbital Flights
Of course, the story of suborbital human spaceflight wouldn’t be complete without recounting a pair of missions that flew there entirely by accident.
On April 5, 1975, veteran Soviet cosmonauts Vasily Lazarev and Oleg Makarov were launched aboard the Soyuz 18 spacecraft for an expected 60-day stay aboard the Salyut 4 space station. However, the third and second stages of the Soyuz booster failed to separate properly at an altitude of 145 km, resulting in an emergency abort.
The cosmonauts were subjected to 21.3 times the force of gravity (21.3 g’s) as the spacecraft during the abort. The Soyuz landed on snow-covered terrain and began rolling down a slope before the parachute snagged on vegetation and stopped it short of a cliff with a 500-foot (152-meter) drop.
Makarov went on to fly three Soyuz missions to the Salyut 6 space station. Lazarev, who suffered injuries during the flight, never flew to space again. He passed away on Dec. 31, 1990 at the age of 62 having never fully recovered from the failed Soyuz launch.
It was the first in-flight abort involving a crewed Soyuz spacecraft. The program would experience a launch pad abort in September 1983 when the abort system blasted the Soyuz T-10-1 spacecraft away after the booster caught fire. Vladimir Titov and Gennady Strekalov survived to fly to space again.
On Oct. 11, 2018, the Soyuz program suffered its second in-flight abort. The Soyuz MS-10 spacecraft performed an emergency landing in Kazakhstan after one of the Soyuz rocket’s first-stage boosters failed to separate properly. Roscomsos cosmonaut Aleksey Ovchinin and NASA astronaut Nick Hague landed safely without injuries after a hair-raising flight that reached 93 km (58 miles).
Ovchinin and Hague will get a second chance to fly to the International Space Station next month. They will be joined by NASA astronaut Christina Koch.