As he prepared for Apollo 11’s lift-off, Neil Armstrong thought he had a 10 per cent chance of dying during the mission, and a 50 per cent chance of not walking on the Moon. “There was still a debate about if you stepped on to the Moon, would you step into 10ft of dust?” says former Nasa official Scott Hubbard.
The entire mission was vulnerable to a single-point failure: if the service module’s engine had failed, for example, there was no back-up.
Nasa’s whole attitude to risk has now changed. Until recently, each system was built to tolerate any two faults. This is now seen as a blunt approach, treating all components as equally important. So Nasa instead tries to limit the probability of failure. The chance of losing SLS and Orion on its first mission is one in 140, according to the agency’s analysis.
That is by Henry Mance and Yuichiro Kanematsu, in the FT, from their splendid look at the current attempt to drive a moon mission. And this:
“We do not have time or funds to build unique, one-of-a-kind systems,” William Gerstenmaier, a senior Nasa official, said recently. The agency’s biggest rocket — Boeing’s troubled Space Launch System (SLS) — will use some of the same engines as the Space Shuttle. Blake Rogers, an engineer at the Aerospace Corporation, a government-funded research agency, told the FT: “2024 is really soon. So there’s not a lot of brand-new technology…Today, Orion’s processing power will still be below 500MHz — significantly less than a MacBook.
Recommended, gated but of course you should subscribe to the FT.