b'The Digital Twin | Engineer InnovationHow do you look at, and solve, the problem of a failing physical asset that is 200,000 miles away and outside direct human intervention (other than from the three astronauts trapped inside who could not even see the damage that had been caused by the explosion)? In the first moments after the explosion, Mission Control struggled just to keep the astronauts alive, conscious that any wrong decision might cause further terminal damage to the fragile spacecraft. Mission Control in Houston worked around the clock. To bring the astronauts home, they would have to work out how to maneuver and navigate a badly damaged spacecraft operating in an unusual configuration that was well outside of its design envelope. They would have to find innovative ways of conserving power, oxygen and water, while keeping astronauts and spacecraft systems alive.Apollo Simulators at Mission Control in Houston. The Lunar Module Simulator is in the And finally, they would have to workforeground in green, the Command Module Simulator is at the rear of the photo in brown.Image credit: NASAout how to restart a command module that was never designed to be switched off in space.success of the Apollo program, and how 50 years ago their flexibility and Behind the scenes at NASA there wereadaptability helped to bring three 15 simulators that were used to trainAmerican astronauts safely home from astronauts and mission controllers indeep space.every aspect of the mission, including multiple failure scenarios (some ofOf course, by itself a simulator is not a which came in useful in avertingdigital twin. What sets the Apollo 13 disaster in both Apollo 11 and 13).In hismission apart as probably the first use autobiography, Gene Kranz describesof digital twin, is the way that NASA that Apollo simulators as some of themission controllers were able to rapidly most complex technology of the entireadapt and modify the simulations, to space program: the only real things inmatch conditions on the real-life the simulation training were the crew,crippled spacecraft, so that they could cockpit, and the mission controlresearch, reject, and perfect the consoles, everything else was make- strategies required to bring the believe created by a bunch ofastronauts home.computers, lots of formulas, and skilled technicians. There were threeBut before we explore the critical role command module simulators, one inthese prototype digital twins played in Houston (where Mission Control wasthe rescue of Apollo 13, its worth located), and two in Cape Kennedy (theexamining how these simulators helped launch site). There were also two lunarprevent disaster for both Apollo 11 and module simulators, one at each13 even before the launch of either location.mission. Although they obviously werent calledUse before launchthat at the time, my contention is thatIf you listen to the audio recordings of these simulators were perhaps the firstthe flight controller loops immediately real example of digital twins. Illafter the explosion, what strikes you explain in this article how these high- most is the sense of controlled calm fidelity simulators and their associatedthat is maintained throughout the computer systems were crucial to theincident. No-one panics, no-one loses 11'