RM-90 Blue Scout II

The RM-90 Blue Scout II was an American sounding rocket and expendable launch system in the Scout family, flown three times during 1961. It was a military version of the NASA-operated Scout X-1, with adjustments to the payload fairings, engine nozzles and fins. The four-stage vehicle was 21.65 metres long with a fin span of 2.84 metres and used four solid-propellant stages, Algol 1B, Castor 2, Antares 1A and Altair 1A, to put a 30 kilogram payload into a 300 kilometre orbit. Two flights in March and April 1961 carried HETS plasma experiments on suborbital paths. The third, on 1 November 1961, was meant to orbit the Mercury-Scout 1 satellite for NASA but went out of control and was destroyed by the range safety officer 43 seconds after liftoff. It and the Blue Scout I were later replaced by Blue Scout Junior.