In the last years, many launch vehicles dedicated to small payloads have emerged. Among them, there is LauncherOne, developed by Richard Branson’s Virgin Orbit. LauncherOne is an air-launched two-stage rocket. Its purpose is to deliver up to 300 kg of payload to a Sun-synchronous orbit, and up to 500 kg to an equatorial Low Earth Orbit. Both stages are fuelled by RP-1 and liquid oxygen. These propellants are used by the Newton Three engine on the first stage and by the Newton Four on the second.
The engines
Newton Three is a pump-fed Kerosene-Oxygen engine. It can generate 327 kN of thrust in a vacuum, or about 33 tons. The engine is designed to operate in a single three-minute burn. It uses a gas generator cycle, meaning some of the propellants are burnt to spin a turbine, which drives the pumps.
Newton Four is also a kerolox engine, however, its nozzle is optimized for the vacuum of space. It generates 22 kN of thrust or about 2 tons. The engine can run for six minutes and can be lit up to three times, to allow for orbital maneuvering and spent stage disposal. It too uses a gas-generator cycle.
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Development history
The development of LancherOne began in 2007. The aim was that of creating a small launcher that would be carried by White Knight Two, the carrier plane for SpaceShipTwo. The goal was to have the latter be a multipurpose vehicle: it would have been able to launch suborbital crewed spacecraft and small orbital rockets. The initial design called for a 200 kg payload, and it employed the Newton One and Two engines.
However, the design evolved. Around 2015, the payload capacity was increased, and consequentially the tanks and engines got bigger. This is where Newton Three and Four were adopted. This made the rocket too heavy for White Knight Two, so a new carrier plane had to be found. The choice fell on Cosmic Girl, a former Virgin Atlantic Boeing 747, which was more than capable of fulfilling the role.
The rocket
At takeoff, the rocket is 21 meters long and 26 tons in mass, including the payload. The rocket is entirely constructed of composite materials. LauncherOne leaves the ground under the left wing of the Cosmic Girl carrier plane. At an altitude of 10.7 km and with a speed of 220 m/s, the rocket is released. Launching from this altitude allows the rocket to avoid most of the atmosphere, and thus a lot of drag.
After a five seconds fall, the Newton Three on the first stage ignites. In three minutes, the launcher reaches an altitude of 90 km. At that point, stage separation takes place, and the Newton Four engine on the second stage comes to life. Shortly after that, the fairing is jettisoned, and the rocket reaches orbital speed six minutes later. Depending on the desired orbit, some additional orbital maneuvers may be performed. During this coast phase, the second stage enters a slow spin to provide thermal control.
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Past missions
After a period of component testing, LauncherOne performed its first launch on May 25, 2020. Cosmic Girl took off from Mojave Air and Space Port and then released the rocket off the coast of California. The engine ignited correctly, and the control system correctly veered the rocket to begin the ascent. However, 9 seconds after the drop, the Newton Three engine shut down, ending the flight.
The cause was eventually traced back to the failure of the high-pressure liquid oxygen line that carried the oxidizer to the engine. As a corrective measure, the whole oxygen feed system was strengthened, and other safety margins were increased. The satellites doomed by this failure were Starshine 4 and INTERNSAT. The former was a sphere with mirrors to allow precise tracking of the satellite and thus the measurement of properties such as the drag it experiences. The latter was an educational payload built by summer interns at Virgin Orbit, and it was supposed to remain attached to the second stage.
LauncherOne returned to flight on Jan. 17, 2021, when it successfully carried into orbit ten CubeSats. The launch was dubbed ELaNa XX (Educational Launch of Nanosatellites), as it was part of the NASA program to launch satellites built by students. The payloads were built by universities across the USA and performed technology demonstrations, Earth science, and space science. Three more successful missions were flown between 2021 and 2022, all taking off from Mojave Air and Space Port.
On Jan. 9, 2023, Cosmic Girl took off from Spaceport Cornwall, ready to launch the first orbital rocket from UK soil. The payload was a host of nine satellites from the UK, the US, Oman (the country’s first satellite), and Poland. They were built to track shipping, observe the ionosphere, and test positioning and space manufacturing technologies. Unfortunately, none of them made it into orbit, as a problem developed with the second stage. The investigation is still underway. Nonetheless, Virgin Orbit CEO Dan Hart has stated that evidence is pointing toward a filter dislodging and causing damage to the engine.
The future
Failing a launch always casts uncertainty upon the future of a rocket. Obviously, we’ll have to wait for the definitive results of the investigation to see LauncherOne fly again. The future isn’t too cloudy though. Deals for launch services are still coming through. For example, Polish satellite manufacturer SatRev has purchased additional payload capacity on future flights. SatRev has long been a Virgin Orbit customer, having launched four satellites on LauncherOne in the past. So, we can look forward to seeing LauncherOne and Cosmic Girl return to flight, hopefully soon.
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