In April 1970, three American astronauts aboard Apollo 13 were 320,000 kilometres from Earth — closer to the Moon than to home — when one of their oxygen tanks exploded, and engineers on the ground had 96 hours to solve a problem so complex the solution was eventually worked out using slide rules and read back to the astronauts to keep them alive

In April 1970, three American astronauts aboard Apollo 13 were 320,000 kilometres from Earth — closer to the Moon than to home — when one of their oxygen tanks exploded, and engineers on the ground had 96 hours to solve a problem so complex the solution was eventually worked out using slide rules and read back to the astronauts to keep them alive

Apollo 13 had been launched four and a half days into a planned ten-day mission that would, if everything had proceeded as designed, have landed Lovell and Haise on the Fra Mauro highlands of the Moon on 15 April, conducted approximately 33 hours of scientific exploration of the lunar surface, and returned all three astronauts safely to Earth on 21 April. The mission was supposed to be the third human lunar landing, following Apollo 11 in July 1…