How digital twin technology helped NASA enact the greatest rescue mission in History
50 years ago, on April 14th, 1970, 55 hours and 55 minutes after launch, Apollo 13 suffered a catastrophic explosion in its service module. Although the astronauts did not instantly recognize the severity of the problem (or even that fact that there had been an explosion). The damage this caused left the Apollo 13 venting oxygen, with a critically damaged main engine, and failing life support systems 200,000 miles away from earth. In the entire history of the human species, no-one had ever been in trouble so far from home. This Slide Share is not the story of the Apollo 13 mission, plenty of others have done a much better job of telling that tale. Instead this is the untold story of the digital twins that helped Mission Control to overcome incredible odds and bring the astronauts home safely.How 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. And finally, they would have to work out how to restart command module that was never designed to be switched off in space.Behind the scenes at NASA there were 15 simulators that were used to train astronauts and mission controllers in every aspect of the mission, including multiple failure scenarios (some of which came in useful in averting disaster in both Apollo 11 and 13). In his autobiography, Gene Kranz describes that Apollo simulators as “some of the most complex technology of the entire space program: the only real things in the simulation training were the crew, cockpit, and the mission control consoles, everything else was make-believe created by a bunch of computers, lots of formulas, and skilled technicians”. There were three command module simulators, one in Houston (where Mission Control was located), and two in Cape Kennedy (the launch site). There were also two lunar module simulators, one at each location. Although they obviously weren’t called that at the time, my contention is that these simulators were perhaps the first real example of “digital twins”. I’ll explain in this article how these high- fidelity simulators and their associated computer systems were crucial to the success of the Apollo program, and how 50 years ago their flexibility and adaptability helped to bring three American astronauts safely home from deep space. Of course, by itself a simulator is not a digital twin. What sets the Apollo 13 mission apart as probably the first use of digital twin, is the way that NASA mission controllers were able to rapidly adapt and modify the simulations, to match conditions on the real-life crippled spacecraft, so that they could research, reject, and perfect the strategies required to bring the astronauts home.But before we explore the critical role these prototype “digital twins” played in the rescue of Apollo 13, it’s worth examining how these simulators helped prevent disaster for both Apollo 11 and 13 even before the launch of either mission.Use before launch If you listen to the audio recordings of the flight controller loops immediately after the explosion, what strikes you most is the sense of controlled calm that is maintained throughout the incident. No-one panics, no-one loses.control, all that you can hear is calm reasoned decision making in the face of a terrible and potentially tragic unfolding situation.This is because the flight controllers, and the Apollo 13 crew, were well- rehearsed through simulation. Before launch, simulators were used to define, test, and refine “mission rules”, the instructions that determined the actions of mission controllers and astronauts in critical mission situations. Among the many simulators, the command module simulators and lunar module simulators occupied 80 percent of the Apollo training time of 29,967 hours.Flight director, Gene Kranz’s, White Mission Control Team (one of three) had 11 days of simulation training to prepare for the landing of Apollo 11, seven of those with the actual crew, and four with simulated astronauts. As well as training both teams, the purpose of the sessions was to define a set of “mission rules” that would define any actions taken by both the crew and mission control these include “Go, No-go” decisions at critical stages of the spaceflight, and how decisions would be made in a crisis.The various simulators were controlled by a network of digital computers, up to ten of them, which could be networked together to simulate a single large problem. There were four computers for the command module simulator, and three for the lunar module simulator. The computers could communicate using 256 kilobytes words of common memory, where information needed throughout the simulation could be stored.There are at least two examples of simulated scenarios that directly influenced the successful resolution of problems on the actual missions (although there are likely hundreds more). In the final simulation of the Apollo 11 mission, controllers wrongly aborted during the final stages of lunar landing.
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. And finally, they would have to work out how to restart command module that was never designed to be switched off in space.
Behind the scenes at NASA there were 15 simulators that were used to train astronauts and mission controllers in every aspect of the mission, including multiple failure scenarios (some of which came in useful in averting disaster in both Apollo 11 and 13). In his autobiography, Gene Kranz describes that Apollo simulators as “some of the most complex technology of the entire space program: the only real things in the simulation training were the crew, cockpit, and the mission control consoles, everything else was make-believe created by a bunch of computers, lots of formulas, and skilled technicians”.
There were three command module simulators, one in Houston (where Mission Control was located), and two in Cape Kennedy (the launch site). There were also two lunar module simulators, one at each location. Although they obviously weren’t called that at the time, my contention is that these simulators were perhaps the first real example of “digital twins”.
I’ll explain in this article how these high- fidelity simulators and their associated computer systems were crucial to the success of the Apollo program, and how 50 years ago their flexibility and adaptability helped to bring three American astronauts safely home from deep space. Of course, by itself a simulator is not a digital twin. What sets the Apollo 13 mission apart as probably the first use of digital twin, is the way that NASA mission controllers were able to rapidly adapt and modify the simulations, to match conditions on the real-life crippled spacecraft, so that they could research, reject, and perfect the strategies required to bring the astronauts home.But before we explore the critical role these prototype “digital twins” played in the rescue of Apollo 13, it’s worth examining how these simulators helped prevent disaster for both Apollo 11 and 13 even before the launch of either mission.
Use before launch If you listen to the audio recordings of the flight controller loops immediately after the explosion, what strikes you most is the sense of controlled calm that is maintained throughout the incident. No-one panics, no-one loses.
control, all that you can hear is calm reasoned decision making in the face of a terrible and potentially tragic unfolding situation.
This is because the flight controllers, and the Apollo 13 crew, were well- rehearsed through simulation. Before launch, simulators were used to define, test, and refine “mission rules”, the instructions that determined the actions of mission controllers and astronauts in critical mission situations. Among the many simulators, the command module simulators and lunar module simulators occupied 80 percent of the Apollo training time of 29,967 hours.
Flight director, Gene Kranz’s, White Mission Control Team (one of three) had 11 days of simulation training to prepare for the landing of Apollo 11, seven of those with the actual crew, and four with simulated astronauts. As well as training both teams, the purpose of the sessions was to define a set of “mission rules” that would define any actions taken by both the crew and mission control these include “Go, No-go” decisions at critical stages of the spaceflight, and how decisions would be made in a crisis.
The various simulators were controlled by a network of digital computers, up to ten of them, which could be networked together to simulate a single large problem. There were four computers for the command module simulator, and three for the lunar module simulator. The computers could communicate using 256 kilobytes words of common memory, where information needed throughout the simulation could be stored.
There are at least two examples of simulated scenarios that directly influenced the successful resolution of problems on the actual missions (although there are likely hundreds more). In the final simulation of the Apollo 11 mission, controllers wrongly aborted during the final stages of lunar landing.