When Apollo 13 was launched on an April morning in 1970, no one foresaw that astronauts James Lovell, John Swigert, and Fred Haise would soon be fighting for survival as one of their oxygen tanks exploded two days into the mission.
Swigert’s now-famous phrase “Houston, we’ve had a problem here” would set in motion a feverish rescue operation to bring the astronauts home safely. As the world held its breath, the NASA flight control team in Houston faced its biggest challenge yet.
How do you resolve technical malfunctions from 200,000 miles away?
Key to the rescue operation was that NASA kept a mirrored system of the Apollo 13 on earth – a physical model of the spacecraft and its components. This allowed engineers on the ground to model and test possible solutions, simulating the conditions on board of Apollo 13.
When the amount of carbon dioxide in Apollo 13’s lunar module rose to life-threatening levels, NASA engineers created an improvised air purifier and instructed the astronauts how to build it with materials available in the spacecraft. At the same time, astronauts on earth ran simulations at Houston and Kennedy Space Center to test procedures for getting the ill-fated crew of Apollo 13 back to earth alive – which they eventually succeeded in, four days after the accident.
Of course, technology has come a long way since 1970. Analogue models have been replaced by digital models, enabling NASA to monitor and modify systems in real time with ever more precision. But the underlying notion is still the same: a model of a physical object – a ‘twin’, so to say – enables you to monitor its status, diagnose issues and test solutions remotely.