Liquid rocket engines pass milestone tests

The two engines, called NewtonOne and NewtonTwo, will be used to carry satellites into orbit from 2016. They are being developed separately from the hybrid rocket motors currently under construction for Spaceshiptwo, the vehicle that will propel tourists into orbit at a cost of $650,000 a time. The Newton engines are fuelled by kerosene and supercooled liquid oxygen and will be able to carry payloads of up to 225kg into low earth orbit at a cost of around $10million. Four companies have signed up to use the launch service so far. George Whitesides, Virgin Galactic chief executive, said: "We are now well on our way to providing customers with the lowest cost opportunity for small satellite manufacturers and operators to buy a dedicated ride to space." The Newton One engine, which will be used during the upper stages of flight, has successfully completed a full-mission duty cycle, firing for a full five minutes. The larger Newton Two engine has been hot-fired several times but only for a few seconds (it will need to fire for a minimum of two and a half minutes for LauncherOne to become a reality). Longer duration firings are due to take place over the coming months.