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Funded by the USAF and NASA, a number of tests were undertaken by Leik Myrabo and Franklin B Mead of the USAF Research Laboratory (AFRL) during the late 1990s at White Sands to prove the ability to propel a small aluminium test vehicle with a series of laser pulses. This night-time trial achieved a height of 72ft (22m). NASA Described as a magnetohydrodynamic (MHD) fanjet, this propulsive method is essentially the next step on from Townsend Brown’s EHD concept and Osmond’s nuclear fusion-powered spacecraft. The Lightship would rapidly reach a velocity of about Mach 3, with Lorentz forces producing thrust, but atmospheric gases have low conductivity soa working system would need to be boosted with a small amount of additional fuel such as hydrogen. At this stage a percentage of the incoming microwave energy would be used to produce a focused point of energy directly before the line of flight called an Air-spike. This would be used to literally cut a path through the atmosphere, allowing rapid acceleration to high hypersonic speeds. Sur- face heating would be dramatically reduced as the airflow formed a shock wave just beyond the vehicle and theoretically Mach 25, which is orbital velocity, would be possible. The air-spike technique appears viable because during the early 1990s Dr Myrabo conducted tests in General Electric’s hyper- sonic wind tunnel and succeeded in produc- ing a Mach 10 parabolic shock wave using a plasma torch. Pavel Tretjakov of the Novosi- birsk Institute of Theoretical and Applied Mathematics produced similar results with a laser at speeds of Mach 2 and believed the air- spike could operate at orbital speeds. These ideas drew widespread interest within the scientific community and similar research began in several laboratories across the country. Meanwhile, Professor Myrabo secured funding from the Space Studies Institute, NASA and the USAF to continue his unique research and by 1996 he was developing new more practical ideas involving laser propul- sion. Working with Franklin B Mead of the USAF Research Laboratory (AFRL) he began a series of experiments with small 0.88-0z (25-gm) aluminium test vehicles at the White Sands Missile Range (WSMR) in New Mexico. These trials began in 1997 and were con- ducted using a pulsed 10-kilowatt infra-red carbon dioxide laser borrowed from the US Army. The test vehicles were normally no larger than 5%in (15.0cm) in diameter and were . <2" 4 af @ \ ; £4 sf 171 In the mid-21st century, a Myrabo Lightcraft lifts off from its launch site. NASA Exotic Propulsion Systems