Seventeen years after Sir Richard Branson watched SpaceShipOne win the Ansari X-Prize, the English entrepreneur and billionaire has flown aboard a successor vehicle known as SpaceShipTwo as part of a crew of six people, the others being Virgin Galactic employees, in a suborbital flight to space.
The flight, known as the Unity 22 Mission, occurred on Sunday July 11 from Spaceport America near Truth or Consequences, New Mexico. The SpaceShipTwo vehicle, VSS Unity, was slung under the purpose-built mothership aircraft known as WhiteKnightTwo or VMS Eve, which took off from the Spaceport America’s 12,000 foot long runway at 8:40 AM MDT (14:40 UTC) before climbing to the release altitude for the flight.
Once VMS Eve, flown by former Shuttle astronaut CJ Sturckow and test pilot Kelly Latimer, reached the release altitude above 45,000 feet, various system checkouts on both VMS Eve and VSS Unity were performed, and the paired aircraft flew in a “racetrack” pattern around Spaceport America before release.
VMS Eve then dropped VSS Unity at 9:25 AM MDT (15:25 UTC) before ignition of the hybrid propellant rocket engine for sixty seconds while in a steep climb.
Once VSS Unity’s rocket engine cut off, the spacecraft’s momentum took it to an altitude of around 90 kilometers. This is above the minimum altitude of 80 kilometers required by the US Air Force, NASA, and the FAA to grant astronaut wings, and is above the discernible atmosphere. This apogee, or maximum altitude, is below the Federation Aeronautique Internationale (FAI) recognized boundary of space at 100 kilometers, which SpaceShipOne crossed twice to claim the X-Prize in 2004.
The craft spent around five minutes in weightlessness, with the crew evaluating the experience and looking at Earth and space from 17 windows on the craft, before they strapped back into their seats for reentry.
The VSS Unity traveled at a speed around Mach 3 during atmospheric reentry, which is a much lower speed than an orbital craft just before reentry, so no extensive heat shielding is required for SpaceShipTwo. Once VSS Unity gets to a lower altitude with more dense atmosphere, the tail booms return to their original position and pilots Dave Mackay and Mike Masucci guided the craft in a gliding pattern toward Spaceport America.
The VSS Unity flew in an unpowered glide with no go-around capability as it lined up with the runway. The landing gear, a skid on the nose and two wheeled units in the wings, was lowered before Unity landed on the runway and braked to a stop.
The crew members for Unity 22 are people experienced with various aspects of Virgin Galactic, and some of them have flown aboard VSS Unity before. Virgin Galactic chief pilot Dave Mackay, from Helmsdale, Scotland, was a Royal Air Force Harrier pilot and a graduate of the French test pilot school, who also flew out of the RAF aircraft test facility at Boscombe Down, England as the commanding officer of the RAF Fast Jet Test Flight. After his military career, Mackay flew as a captain of Boeing 747 and Airbus A340 airliners for Virgin Atlantic before his current job with Virgin Galactic and has logged over 11,000 flight hours.
Mackay was one of the pilots who flew the VSS Enterprise, the first SpaceShipTwo built, and flew to space on February 22, 2019 aboard VSS Unity, becoming the 569th person and first Scotsman to fly above 80 kilometers altitude.
Mike “Sooch” Masucci was a US Air Force lieutenant colonel who flew U-2 reconnaissance aircraft on operational combat missions as well as over 80 other aircraft types. He graduated from the US Air Force Test Pilot School at Edwards Air Force Base, California and later was an instructor there as well as a branch chief. After his military career, he was a pilot for XOJET flying Cessna Citation X business jets before joining Virgin Galactic. He has over 10,000 flight hours and is Virgin Galactic’s lead trainer pilot.
Masucci was one of the pilots of Unity VF-01, along with Dave Mackay, who flew to space in February 2019, along with Virgin Galactic astronaut trainer Beth Moses. The flight reached an apogee of 89.9 km and Masucci became the 570th person to fly above 80 kilometers, with Moses becoming the 571st.
Beth Moses, from Northbrook, Illinois, is a graduate of Purdue University’s School of Aeronautics and Astronautics who joined NASA as an engineer in the EVA Project Office at the Johnson Space Center. She was the assembly manager for the International Space Station and led human-in-the-loop testing for ISS assembly before joining Virgin Galactic, where she is now the lead astronaut trainer and interiors program manager.
Aboard the Unity VF-01 flight, Moses became the first woman to earn commercial astronaut status and also became the first person to unstrap and float around a passenger cabin during suborbital flight as she evaluated the passenger experience.
Like Beth Moses, Sirisha Bandla is an alum of Purdue’s School of Aeronautics and Astronautics. Born in Guntur, Andhra Pradesh, India, Bandla was an aerospace engineer at L-3 and an associate director for the Commercial Spaceflight Foundation. She joined Virgin Galactic in 2015 and is currently the company’s Vice President of Governmental Affairs and Research Operations.
This was Bandla’s first suborbital flight. Aboard Unity 22, Bandla operated the University of Florida’s microgravity plant experiment which requires her to handle the experiment’s fixation tubes at various points in the flight. This was done to evaluate the research experience in flight. Bandla would be the second woman born in India and third American woman of Indian descent to fly above the FAA-recognized boundary of space.
Colin Bennett, from Clevedon, England, graduated from the University of Liverpool with a Master’s degree in aerospace engineering and worked for QinetiQ and Virgin Atlantic as an engineer before joining Virgin Galactic, where he currently is lead operations engineer.
This was Bennett’s first suborbital flight as well. Aboard Unity 22, Bennett evaluated the cabin equipment and experience during the flight.
The third British-born crewmember on this flight is the founder of Virgin Galactic. Richard Branson, born in Blackheath, London, England, tried several business ventures in his youth before he founded Virgin Records in the early 1970’s as a new record label due to his interest in music and Mike Oldfield’s song “Tubular Bells.”
VSS Unity and its mother ship White Knight Two this morning. We’re now less than 12 hours away from tomorrow’s launch attempt! Shout out to the excellent folks at @Spaceport_NM for granting me some access today. @NASASpaceflight @virgingalactic #Unity22 pic.twitter.com/yxXWmkRdea
— Jack Beyer (@thejackbeyer) July 11, 2021
By the end of the 1970s, Branson was a millionaire. As his wealth was building up, he founded Virgin Atlantic Airways in 1984, which challenged British Airways in the transatlantic market and became a successful airline. The Virgin Group expanded into many business areas, including the founding of Virgin Galactic in 2004.
On this flight, Branson evaluated the passenger experience, and if all goes as planned he would beat fellow billionaire Jeff Bezos to flying past the 80 kilometer U.S. recognized boundary of space by nine days. He hopes to be first of many well-heeled travelers aboard VSS Unity and its follow-on sister ships; there is a list of six hundred people from sixty countries who had paid deposits to fly on Virgin Galactic before 2018 along with interest from thousands of people after ticket sales resumed early last year.
After SpaceShipOne won the X-Prize in 2004, there was major public interest in the prospect of space tourism, and Virgin Galactic was among a host of companies that started up to serve this interest. Branson and Virgin Galactic teamed up with Burt Rutan and Scaled Composites to develop a follow-on ship called SpaceShipTwo that would be based on the design concepts used by SpaceShipOne, including a hybrid engine powered by liquid nitrous oxide and a solid rubber-based fuel, to combine the best characteristics of liquid and solid-fueled engines.
However, the engine’s development suffered a setback in 2007 when a tank of nitrous oxide exploded at Scaled Composites’ facility in Mojave, killing three workers and seriously injuring three others, and resulting in fines for safety violations against Scaled. While the engine’s issues were being worked, the airframe for the first SpaceShipTwo was being built in Mojave, and the SpaceShipTwo mothership aircraft, VMS Eve, was completed and rolled out in the summer of 2008.
While VMS Eve was undergoing its own flight tests, the first SpaceShipTwo airframe, VSS Enterprise, was being finished in Mojave. VSS Enterprise rolled out in December 2009, but initial projections of tourist flights starting in 2011 were repeatedly pushed back as testing was taking longer than planned, which is not uncommon in spaceflight. However, Virgin Galactic took pre-orders for flights and ordered five SpaceShipTwo craft, and was publicly optimistic about the future of space tourism, especially on its SpaceShipTwo.
In 2012, The Spaceship Company, which was jointly formed by Burt Rutan and Virgin Galactic in 2005, became wholly owned by Virgin Galactic, and Scaled Composites had been acquired by Northrop Grumman in the meantime.
After glide tests beginning in 2010, where VSS Enterprise was dropped from VSS Eve and glided to a landing without firing any rocket engines, and after a protracted development, the rubber-based HTPB and nitrous oxide hybrid engine was finally ready for flight by early 2013. In April 2013, after numerous glide and captive carry tests, VSS Enterprise made its first powered flight to 56,000 feet and at a speed of Mach 1.22 before landing at Mojave Air and Space Port.
VSS Enterprise flew two more powered flights with a maximum burn time of 20 seconds in September 2013 and January 2014 while issues with the engine were worked and the solid propellant changed to a nylon-based fuel for greater performance. The new engine was ready by the fall of 2014 and on October 31, 2014 Scaled Composites pilots Peter Siebold and Michael Alsbury boarded Enterprise for its first powered flight in nine months.
VMS Eve reached its release altitude of 47,000 feet and dropped VSS Enterprise, which ignited its new engine and began its climb. Eleven seconds later, Enterprise broke apart in midair and its remnants were scattered in the California high desert, in a 35 mile long debris field. Michael Alsbury was killed in the crash, becoming the first spaceflight fatality since the 2003 Columbia disaster, while Peter Siebold survived as the craft broke up around him and he was still in his seat. Siebold parachuted to the ground and was seriously injured but recovered.
The VSS Enterprise disaster was a huge setback not just for Virgin Galactic but for the space tourism industry as a whole. The promise of regular space tourism flights by multiple companies that had been talked up in the first decade of the 21st century had been replaced by repeated schedule delays, testing setbacks, and bankruptcies of companies like XCOR and Rocketplane, which aimed to provide suborbital human spaceflight services of their own.
The NTSB investigation into the VSS Enterprise disaster found that the tail feathering system had been unlocked by Alsbury nine seconds into the flight, at a speed of Mach 0.92. During transonic flight, there would be enormous upward pressure on the tail surfaces, and when the locks were released, the actuators were not able to keep the tail booms in place. Aerodynamic breakup happened very shortly after the tail booms moved, as they were designed to be deployed much later in flight, where the aerodynamic forces would be much less and the atmosphere would be much thinner.
The NTSB report faulted the lack of a fail-safe system and the possibility of a single-point human failure, and also noted poor pilot training and lack of sufficient FAA oversight as well as the copilot Alsbury’s lack of recent flight experience. After the VSS Enterprise crash, Virgin Galactic took full responsibility for the future test program and worked on incorporating new safety features into the VSS Unity craft then under construction.
VSS Unity was unveiled in February 2016 and made its first captive-carry flight in September of that same year, staying firmly slung to the underside of VMS Eve. Throughout the end of 2016 and 2017, Unity made unpowered glide flights. In April 2018, Unity made its first powered flight, using a hybrid engine based on rubber (HTPB) fuel and nitrous oxide, reverting from the nylon fuel used on VSS Enterprise’s last flight.
In July 2018, VSS Unity reached the mesosphere for the first time, attaining an altitude of 52.1 kilometers, and on December 13, 2018, VSS Unity and its pilots Mark Stucky and CJ Sturckow became the first crewed vehicle to attain the altitude of 80 kilometers from U.S. soil since STS-135, reaching 82.7 kilometers at apogee. Unity landed safely at Mojave and preparations began for its second flight to the edge of space.
On February 22, 2019, VSS Unity reached an 89.9 kilometer apogee with pilots Mackay and Masucci as well as Beth Moses in the passenger cabin, being the first crew member to fly aboard Unity as a passenger. During the flight, a seal broke in the starboard wing. VSS Unity landed safely at Mojave despite the broken seal in the wing and a safety audit was started.
Virgin Galactic’s operations were moved from Mojave to Spaceport America in New Mexico, a public, commercial spaceport that the company had earlier chosen as its location for operational flights, while the company publicly stated that Unity would be getting a new interior before restarting flights.
With safety concerns from February’s flight still not publicly revealed, VMS Eve was flown to Spaceport America and preparations were made to resume glide flights of VSS Unity after the audit was complete. Starting in March 2020, the COVID-19 pandemic complicated flight preparations, but Virgin Galactic finally got Unity back in the air for an unpowered glide flight in May.
— Jack Beyer (@thejackbeyer) December 12, 2020
Six months after a second glide flight, after some more delays caused by the pandemic, VMS Eve and VSS Unity took to the air on December 12, 2020 for the first flight to the edge of space from New Mexico. However, just after release from VMS Eve, electromagnetic interference caused the flight computer to lose communication with the engine electronics, and the hybrid rocket engine was shut down just after ignition. Pilots Mackay and Sturckow landed Unity safely at Spaceport America, and the flight showed that SpaceShipTwo’s intact abort capability worked under real world conditions, good news for future flights.
Virgin Galactic worked to solve the EMI problem, and after a further delay from February 2021 due to the need to rework some items related to the EMI issue, VSS Unity VF-03 (Unity 21) flew on May 22, 2021, becoming the first flight from New Mexico to reach the U.S. definition of space, and pilots Mackay and Sturckow landed the ship safely at Spaceport America. Following the flight, the FAA granted Virgin Galactic approval to fly passengers on commercial flights.
During this timeframe, billionaire Jeff Bezos, who founded competing company Blue Origin, announced that a crew of four, including himself and his brother, would fly to space and back aboard the first human flight of New Shepard on July 20, the 52nd anniversary of the Apollo 11 lunar landing, following 15 successful uncrewed test flights.
Shortly after this, Sir Richard Branson, who had planned to fly aboard VSS Unity after an additional flight with several crewmembers, announced that he would fly aboard the next flight of Unity on July 11.
Unlike SpaceShipTwo, the New Shepard rocket and capsule system, with a capacity of six people, has demonstrated the capability of flying past the Federation Aeronautique Internationale (FAI) recognized boundary of space, named after physicist Theodore von Karman, at 100 kilometers above Earth, before the rocket makes a landing vertically on a concrete pad and the capsule parachutes to a landing in the West Texas desert near Van Horn, around 200 miles southeast of Spaceport America.
Defining the boundary between Earth’s atmosphere and space continues to be a matter of debate. Eight X-15 pilots have received their astronaut wings after flights past 80 kilometers.
Physicist and engineer Theodore von Karman calculated the height at which aerodynamic forces could keep planes flying, and found that the atmosphere would be too thin for sufficient lift at an altitude of 83.6 kilometers, which is approximately at the turbopause where atmospheric gases are not well mixed. This area is also where the atmospheric mesopause is found, the boundary between the mesosphere and the thermosphere.
The Federation Aeronautique Internationale, the governing body based in Lausanne, Switzerland that is the world governing body for aviation sports and records, defined the Karman line to be at 100 kilometers above Earth in 1960, as an easy round number to define where aeronautics ends and astronautics begins. This standard has held for many years, although the FAI has indicated a willingness to revisit this in recent years, as interest in this boundary grows and new research comes forward.
In a recent episode of NSF Live, astrophysicist Jonathan McDowell discussed the peer-reviewed paper he published in 2018 regarding the boundary of space and stated “the effective Karman line, the point of which aerodynamics stops winning against gravity, is about 80 kilometers”. He also stated that if you take von Karman’s argument seriously, the number you pick is somewhere around 80, and that if a satellite in an elliptical orbit has its perigee drop below 80 kilometers it will re-enter the atmosphere, as a result of calculations he performed to study where space begins.
McDowell himself uses the line at 80 kilometers as his definition of spaceflight for his own Space Report. Some programs have also had their own definition of the boundary of space for operational purposes. The Soviet program had a boundary of around 90 kilometers that would mark the reentry of the Soyuz capsule, and the Space Shuttle program had a definition of reentry starting at 122 kilometers, where atmospheric drag became noticeable for the vehicle.
There is no set standard in international law for when space begins. The Soviet Union had proposed a 100 kilometer boundary to the United Nations’ COPUOS (Committee on Peaceful Uses of Outer Space) in the 1960s but the United States rejected this, stating that there did not need to be a set line and no legal or practical problems have resulted from this lack of a set definition. The Outer Space Treaty does not have a defined boundary of where space begins.
The “no set boundary” standard has been U.S. policy to the present day, though the military’s USSPACECOM announced that its area of responsibility (AOR) starts at altitudes at or greater than 100 kilometers above sea level in August 2019, while the Joint Chiefs of Staff defines the space domain as “the area above the altitude where atmospheric objects on airborne objects become negligible” as per the Joint Publication 3-14 Space Operations document published in April 2018 and revised in October 2020.
As SpaceShipTwo and New Shepard continue to fly people on suborbital flights, both as tourist adventures and for scientific research, this question and others will no doubt be debated, while Branson and other space entrepreneurs hope that the “overview effect” of seeing Earth from space inspires more and more people.
(Lead photo via Jack Beyer for NSF)