SpaceShipTwo VSS Unity passes major milestone
After two years of extensive ground and atmospheric testing, the passing of this milestone marks the start of the final portion of Unity’s flight test programme.
The flight was also significant for Virgin Galactic’s Mojave based, sister manufacturing organisation, The Spaceship Company. Unity is the first vehicle to be built from scratch for Virgin Galactic by The Spaceship Company’s talented team of aerospace engineers and technicians.
VSS Unity benefits from all the data and lessons gathered from the test program of her predecessor vehicle, VSS Enterprise.
The 5th of April flight saw an envelope expansion for the programme as a whole in terms of rocket burn duration, speed and altitude achieved.
VSS Unity took off on the morning of 5th April into clear Mojave skies at 8:02am with Mark “Forger” Stucky and Dave Mackay in the cockpit, attached to the WhiteKnightTwo carrier aircraft, VMS Eve, piloted by Mike Masucci and Nicola Pecile.
The mated vehicles climbed to a launch altitude of around 46,500ft over the Sierra Nevada Mountains and while pointing back at Mojave, Eve executed a clean release of Unity. After a few seconds, Unity’s rocket motor was brought to life and the pilots aimed the spaceship upwards into an 80 degree climb, accelerating to Mach 1.87 during the 30 seconds of rocket burn. The hybrid (nitrous oxide / HTPB compound) rocket motor, which was designed, built and tested by The Spaceship Company, powered Unity today through the transonic range and into supersonic flight for the first time.
On rocket shutdown, Unity continued an upwards coast to an apogee of 84,271ft before readying for the downhill return. At this stage, the pilots raised the vehicle’s tail booms to a 60 degree angle to the fuselage, into the ‘feathered’ configuration. This unique design feature, which is key to a reliable and repeatable re-entry capability for a winged vehicle, incorporates the additional safety mechanisms adopted after the 2014 VSS Enterprise test flight accident.
At around 50,000ft, the tail-booms were lowered again and, while jettisoning the remaining oxidizer, Unity turned towards Mojave for the glide home and a smooth runway landing.
The flight has generated valuable data on flight, motor and vehicle performance which Virgin Galactic’s engineers will be reviewing. It also marks a key moment for the test flight programme, entering now the exciting phase of powered flight and the expansion to full duration rocket burns.
