Orion Versions

The baseline planetary version of Orion would have launched from the earth's surface. It would have been bullet-shaped, 41 m in diameter and about 50 m high.

Launch would have been from the Atomic Energy Commission test site at Jackass Flats, Nevada. Initially 0.1 kiloton bombs would have been exploded behind the pusher plate at one second intervals. Once clear of the earth's atmosphere and radiation belts this would gradually increase until 20 kiloton bombs would be ignited every ten seconds. The 10,000 tonne ship would hold 2000 bombs and have a net payload of several thousand tonnes, sufficient to house a crew of 150 in comfort.

The rocket would have had an exhaust velocity of 3000 seconds and be able to make the round trip to Mars in two years. Jupiter or Saturn would take only three years round trip. On a Jupiter voyage the approach velocity would be 67 km/sec and the braking manoeuvre would take only 1000 seconds. The voyage could be made even shorter if the ship would refuel with propellant at Callisto - water or frozen methane or almost any available ice could be used.

Manufacturer: General Atomic. Total Mass: 10,000,000 kg (22,000,000 lb).

• Brower, Kenneth, The Starship and the Canoe, Bantam, 1979. ISBN: 0030391962. A meditation on the values and lives of Frederick Dyson, weapons scientist, father of the Orion nuclear pulse starship, and his son, who lives in the Pacific Northwest forest and builds canoes. More at amazon.com...