Atomic adventures in Space

 Letter sent  to The Times on 26 July

Your technology correspondent in his fascinating report on the latest ideas to use nuclear power in space (“Big blast off: nuclear engine could propel rockets into deep space,” July 25 http://www.thetimes.co.uk/tto/technology/article4507904.ece ) wrote that “in the late 1940s NASA;s   [the US National Aeronautics and Space Administration] Project Orion suggested propelling spacecraft with a series of explosions from atomic bombs.”

Such ideas did indeed begin immediately post war, when general proposals of nuclear propulsion were first made by Polish-American mathematician Stanislaw Ulam in 1946, and preliminary calculations were made by American physicist Frederick and Ulam in a memorandum at the Los Alamos atomic research labs memorandum dated 1947, but this was not by NASA, which was not created until a decade later by US President Eisenhower  1958.

In 1959, NASA began work Nuclear Engine for Rocket Vehicle Application (NERVA) with the US Atomic Energy Commission to develop a nuclear powered rocket to carry astronauts into space, but the project was ended in 1973

In 1972 and 1973 Nasa then launched its Pioneer space probes, which used 155-watt nuclear batteries to keep them powered; and The Viking landers, which touched down on Mars for the first time in 1976, also used plutonium batteries to power their experiments; and the Voyager probes, which have become the first manmade objects to leave the solar system, also relied upon three plutonium-238 batteries that have allowed them to communicate with Earth for 36 years

Bur launching nuclear powered-propulsion n units have serious risks NASA’s  failed meteorological Nimbus B1 satellite blew up on launch in 1968, containing . plutonium batteries.

The nuclear  pack in this case  was tiny and later recovered, but in the much bigger rockets now under discussion could much bigger dangers if an accident took place on launch

A year ago The Times carried another excellent article on the use of nuclear blast in space (“Americans planned nuclear explosion on the Moon. “ July 25 2014,

http://www.thetimes.co.uk/tto/news/world/americas/article4158080.ece), when James Hider wrote about  the US Project Horizon drawn up in 1959.

Hider article followed the revelations by the late, great populist American astronomer Carl Sagan, who unveiled  decade earlier in Nature details of t

he top-secret Project A119 in 1958-59 that reported on 'A Study of Lunar Research Flights' to investigate the visibility and effects of a nuclear explosion on the moon.(

Nature, vol. 405, May 4, 2000, p.13

http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v405/n6782/full/405013a0_fs.html&_UserReference=C0A804EC4651E9676AE1547DDF8A3BB371F)

With the plutonium-powered New Horizons space probe having spectacularly just reached Pluto, no doubt the merits of use of nuclear power in space will be firmly back on NASA’s agenda