Engineering news
First was Sir Richard Branson, who flew 85km up on board Virgin Galactic’s Unity rocket plane on Sunday 11 July.
Today (20 July) it was the turn of Amazon founder Jeff Bezos, aboard the New Shepard rocket. Although beaten by Branson by nine days, Bezos reached an altitude of about 107km during the flight – above the 100km Karman Line, commonly thought of as the edge of space.
While some have questioned the merits of turning space into a tourist destination, the engineering behind both projects is nonetheless remarkable. Here’s a quick round-up of features on both spacecraft.
Unity – Virgin Galactic
VSS Unity is the first SpaceShipTwo spacecraft to enter service. The craft makes up one half of the SpaceShipTwo system, which also consists of WhiteKnightTwo – a custom-built, four engine, dual fuselage carrier aircraft, designed to carry SpaceShipTwo over 15km up before releasing it.
Unity is a reusable, winged spacecraft that can carry six passengers and two pilots. It has a hybrid rocket motor, with both a solid and a liquid element – solid hydroxyl-terminated polybutadiene (HTPB) fuel and liquid nitrous oxide oxidizer. The approach aims to provide the simplicity of a solid motor, with the controllability of liquid.
SpaceShipTwo can change shape during flight to enable safe re-entry. While in space, the wings and tail booms are rotated upwards, allowing the vehicle’s aerodynamics to control stability and rate of deceleration as it descends.
The two-vehicle system is designed to enable frequent trips, while also maximising safety, passenger experience and energy efficiency.
New Shepard – Blue Origin
Unlike SpaceShipTwo, New Shepard is a more conventional rocket ship. The craft includes a single booster, which uses the company’s liquid hydrogen and liquid oxygen BE-3 engine to carry a passenger capsule up to about 76km. The capsule then detaches and continues upwards to the peak of the flight, while the booster starts a controlled return to Earth.
The capsule has room for six passengers – but no pilots, thanks to the on-board computer control. Blue Origin boasts that the capsule’s windows are the ‘largest in space’, with each astronaut sitting in a reclining chair next to their own window.
The firm also stresses the safety of its system. The test programme included 15 successful consecutive missions, including three successful tests of the crew escape system. The system – designed to push the capsule away from the booster in the event of an issue – can be deployed at any point during the flight. The capsule also has a retro-thrust system to slow down to just 1.6km/h as it parachutes back to land.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.