After years of development, suborbital space tourism looks ready to lift off after Virgin Galactic successfully launched its first fully-crewed suborbital mission to space on July 11 following several prior crewed suborbital tests. The Unity 22 mission came just days before Blue Origin is scheduled to make its first passenger suborbital mission no earlier than Tuesday, July 20 using its New Shepard system.
Both companies have been developing suborbital spacecraft for over a decade, with the ultimate goal of carrying paying customers to the edge of space and back along with an added commitment to take science experiments along on some but not all of those flights as well.
History of human suborbital spaceflight
On May 5, 1961, Alan Shepard became the first person to fly a suborbital mission to space. And became the first American to travel to space in the process. Shepard’s mission launched from Cape Canaveral and took his Freedom 7 Mercury capsule to an altitude of 187.5 km, before making a safe splashdown in the Atlantic ocean.
After Shepard’s flight, the Air Force’s X-15 hypersonic rocket-powered aircraft also began making suborbital flights. On July 17, 1962, during X-15 Flight 62, pilot Robert M. White flew the rocket-powered spaceplane up to an altitude of 95.9 km, crossing the boundary to space at 80 km as used by the United States.
The X-15 conducted a total of 13 suborbital spaceflights between 1962 and 1968, including two that crossed the Kármán line (the 100 km boundary to space used officially by most of the world — read Jonathan McDowell’s paper examining where the aerodynamic-to-gravity-dominate boundary to space likely resides). Those two flights were piloted by Air Force pilot Joseph A. Walker and remain the highest flights achieved by the X-15.
An X-15 in flight. (Credit: US Air Force)
Although the X-15 was operated by the U.S. Air Force and NASA, and was never intended for tourism, the program helped pave the way for the development of commercial suborbital rocket powered spaceplanes such as Virgin Galactic’s SpaceShipOne and SpaceShipTwo.
In May 1996, the Xprize, later renamed the Ansari X Prize, promised to award $10 million to the first non-government organization to launch a crewed spacecraft to space and back twice within two weeks.
The goal of the prize was to help spur the development of low-cost spaceflight, a must if a commercial market was ever to develop. The competition comprised 26 teams from around the world who raced to develop a spacecraft that would meet the requirements.
The prize was won on October 4, 2004, when Scaled Composites completed its second piloted suborbital flight within two weeks using their SpaceShipOne spaceplane. The first flight for the prize occurred five days earlier on September 29.
This was the third time SpaceShipOne was launched, with the first flight occurring on June 24, 2004. The flights, respectively, reached 100.1 km, 102.9 km and 112 km.
Virgin Galactic
The company currently operates the SpaceShipTwo, named VSS Unity, and the WhiteKnightTwo, VMS Eve, carrier aircraft. The first SpaceShipThree craft, the VSS Imagine, was recently unveiled and is awaiting ground and flight tests scheduled to begin this summer (northern hemisphere).
VSS Unity is the second SpaceShipTwo vehicle developed by Virgin Galactic. The first, VSS Enterprise was lost in a deadly accident over the Mojave Desert in California on October 31, 2014.
After a successful climb to altitude and release from its carrier aircraft, VSS Enterprise ignited its engine at 15 km altitude to begin climbing. Just 11 seconds into the burn, the co-pilot prematurely unlocked the feathering mechanism, resulting in the violent aerodynamic breakup of the Enterprise.
The breakup ejected pilot Peter Siebold, still strapped to his seat, who managed to unbuckle himself — despite severe injuries — and safely parachute to the ground. Co-pilot Michael Alsbury died in the crash.
The National Transportation Safety Board (NTSB) ultimately determined the cause of the accident to be a combination of pilot error, inadequate pilot training, spacecraft design flaws that provided no safeguards against accidental pilot command of critical systems at the wrong time in flight, and the FAA for approving the experimental test flight without paying adequate attention to human safety factors or providing guidance.
VSS Unity, named by physicist Stephen Hawking, was about 65% complete at the time of Enterprise’s loss and incorporates lessons learned and post-accident redesigns.
VSS Unity can carry up to four passengers and two pilots. After taking off from Spaceport America in New Mexico, Unity is carried up to just under 15 km by its carrier aircraft VMS Eve. Once at the drop altitude, Unity is released from its mothership and enters a short free fall before igniting its single hybrid rocket motor.
VMS Eve and VSS Unity taking off from @Spaceport_NM yesterday. #Unity22 @NASASpaceflight pic.twitter.com/QlgggtNE10
— Jack Beyer (@thejackbeyer) July 12, 2021
The motor, burning nitrous oxide and hydroxyl-terminated polybutadiene, fires for around one minute, producing 310 kN of thrust with a specific impulse of 250 seconds to bring Unity’s maximum altitude from 15 km to approximately 85 km. Once the engine shuts down, crew and passengers begin to experience approximately 4 minutes of weightlessness and are allowed to unbuckle from their seats and float around the cabin.
During this time, the craft also begins to “feather,” a process where the wings fold into a vertical position in preparation for re-entry. This orientation ensures the craft remains relatively flat during its descent back into Earth’s atmosphere.
After re-entry, the wings fold back into their normal horizontal position, and Unity glides back to land on the same runway it was carried from at Spaceport America.
Virgin Galactic currently has about 600 people signed up for flights, with tickets going for $250,000 as of last report. The company is currently targeting the beginning of next year to start flying its first paying customers.
During the July 11 mission, Branson announced the chance two win two seats aboard a future Virgin Galactic flight, allowing two people the chance to fly to space without needing to pay the ticket price.
Blue Origin
New Shepard is a single stage suborbital rocket consisting of the New Shepard booster and capsule. It lifts off from a traditional launch pad, and the booster propulsively lands while the capsule touches down under parachute and retrorocket assistance.
Recovery teams work on the New Shepard capsule following the NS-10 mission (Credit: Blue Origin)
The vehicle launches from Blue Origin’s West Texas facility near Van Horn and is powered by the company’s liquid hydrogen and liquid oxygen (hydrolox) BE-3 engine.
After liftoff, the booster carries the capsule up to a velocity that allows it to coast upward to between 105-110 km altitude. The booster separates after the boost phase of flight, with both the booster and capsule then following separate trajectories.
The up-to six passengers experience approximately 4 minutes of weightlessness.
Another major difference between the two vehicles is that New Shepard is fully automated, whereas the VSS Unity requires two pilots to manually fly the vehicle all the way up and back down again.
The New Shepard system has undergone 15 uncrewed test flights and a pad abort test. Of those 15 flights, two included tests of the in-flight abort system, and numerous flights carried science experiments as well. A New Shepard booster, on November 23, 2015, became the first rocket to successfully conduct a vertical, retro-propulsive landing after launching a payload toward space.
On July 20, Blue Origin is scheduled to launch company founder Jeff Bezos, his brother Mark, the winner of a seat auction, as well as a member of the “Mercury 13,” Wally Funk. The “Mercury 13” were a group of women who underwent many of the same physiological and psychological training programs as early NASA male astronauts. The program was never official, and none of the women ever flew in space.
Wally, now 82, will see her dream of flying to space come true. When she flies, she will be the oldest person to reach space, breaking the current record set by John Glenn in 1998 when, at the age of 77, he flew the week-long orbital mission of STS-95 aboard the Space Shuttle Discovery.
Wally Funk with Jeff Bezos. (Credit: Blue Origin)
On Thursday, Blue Origin confirmed the final passenger on the mission: 18 year old Oliver Daemen. Oliver is not the winner of the $28 million auction; that person, despite knowing the date of the flight at the time of the auction, now has a “schedule conflict,” according to Blue Origin.
At 18 years old, Oliver will become the youngest person to reach space, a record currently held by Soviet cosmonaut Ghermon Titov, who flew an orbital mission at age 25.
Oliver’s seat was bought by his father, a hedge fund manager.
In terms of operations, Blue Origin has not yet revealed ticket prices, apart from the seat which was auctioned off for $28 million USD in support of Blue Origin’s Club for the Future charity.
And that part will be important. Exactly what the price point will be and therefore how accessible it really is for regular people who don’t have a quarter-million dollars to drop on a 5 minute experience is an important part of this equation that is not yet known.
Still, the tourism market does intersect with the suborbital science community. Both Virgin Galactic and Blue Origin are committed to carrying science payloads on these suborbital missions (not all of them) for NASA, other space agencies, universities, and research institutions.
(Lead image: New Shepard lifts off on an uncrewed suborbital test flight. Credit: Blue Origin. )