The three landing methods were Direct Approach, Earth orbit rendezvous and Lunar orbit rendezvous. The Lunar orbit rendezvous was the one chosen for moon landings and is the only one that would allow the Apollo 13 crew to survive the oxygen tank explosion and return to Earth. A very interesting article!!!
An irritating Apollo 13 movie note: in the movie, once they power down, everything gets cold and wet “because there’s no heat.” Why this was allowed is beyond me - in truth, they’d roast by their own body heat. The vacuum of space is an INSULATOR. You know those “solar panels” on the International Space Station? Most of them are actually RADIATORS, to dissipate heat into space, otherwise the astronauts would be living (and dying) in an oven.
One of the reasons that Apollo 13 safely returned was due to a Texhnical Note written in 1959 by Barbara J. Short entitled. Point Return Landings From the Moon to the Eartth
This gave the equations needed for trajectory and burn rates
Nowadays, NASA would depend less upon choosing the right route, but merely upon the will of Allah.
A basic Failure Modes and Effects Analysis would have identified the lunar orbital option as the only acceptable one, as history has verified.
If they hadn’t named it Apollo 13 and skipped the number like they were advised, they wouldn’t have had all those problems.
Back in the days when America had balls.
Now, we have snowflakes and crybullies.
It’s amazing what you can do with slide rules. Just think, if they had used Common Core, we’d still be waiting to get there.
Crewcuts and neckties for the win.
bump