Well, Tom, as you know, there are Rockets and Rockets.

There's a big difference between solids and liquids, and with different liquids. LOx and LH2 NEED to be refrigerated, so, in a sense, it doesn't matter what the temperature is - the whole fuelling system must be designed to cryogenically chill the fuel AND deal with boil-off.

Rutan's problem came with his hybrid fuel system, and in apparently believing that liquid NOx was a "safe" liquid. The handling system and test procedures were not, according to what I have learned from published reports, designed to cover the extremes of behaviour of NOx on a hot day. And guess what happens in the Mojave desert - you get hot days...

Firm is fined over 3 fatalities

Scaled Composites, the fledgling space tourism company founded by rocket pioneer Burt Rutan, was fined $25,870 on Friday as a result of an accident last July that killed three workers at the firm’s Mojave, Calif., testing facility.

The fine covered five violations of workplace safety codes, including a failure to maintain a safe working environment and to properly train workers handling hazardous materials, according to the California Division of Occupational Safety and Health.

The three workers – Eric Dean Blackwell, 38; Charles Glen May, 45; and Todd Ivens, 33 – were killed in an explosion at a remote testing site at the Mojave Air and Space Port on July 26.

Three other employees were injured in the blast, which occurred when a tank of nitrous oxide ignited during a test of the spacecraft’s propellant system.