Stavo riguardando i video della ripartenza del modulo lunare (16 e 17) e mi sono posto la stessa domanda che Massimo si è posto sui ritardi dovuti alla distanza terra luna. In particolare, quando gli astronauti danno il comando di accensione, ignition, la telecamera che inquadra il lem inizia quasi immediatamente a risalire. Ci sono due scenari possibili a questo punto per gli operatori da terra. Il primo-l'operatore attua la telecamera appena riceve il la voce dell'astronauta che dice ignition. Il secondo- l'operatore attende che il lem inizi la risalita e poi attua la telecamera. Nel primo scenario la cosa non torna : Infatti ho contato poco più di un secondo dal momento del comando di accensione, ma anche lì non sarebbe possibile, perché, supponendo che audio e video siano in sync, sarebbero necessari (almeno) poco più di due secondi per ricevere l'audio e attivare la videocamera.
Nel secondo scenario, quello in cui l' operatore da terra attendeva le immagini, ho contato 2,15 secondi col cronometro e anche lì mi sembrano davvero pochi.
Tralascio poi il fatto che l'operatore da terra non conosceva il rateo di salita del lem e quindi non mi spiego come abbia fatto a seguire il lem nella sua ascesa.
Attendo i vostri commenti e quello di Massimo, grazie!
As the Smithsonian National Air and Space Museum explains in a 2011 blog post, the camera was available on Apollos 15, 16 and 17. The television camera communicated from Earth using a high-gain antenna on the rover, but there was a slight time delay for the radio waves to travel (a couple of seconds) between the Earth and the Moon.
So the engineers suggested moving the rover a certain distance from the lunar module and setting the camera to automatically tilt to show the lunar liftoff when commanded from Earth.
That was the plan, at least. On Apollo 15, the tilt mechanism malfunctioned and the camera never moved upwards, allowing the lunar module to slip out of sight. And while the attempt on Apollo 16 gave a longer view of the lunar module rising up, the astronauts actually parked the rover too close to it, which threw off the calculations and timing of the tilt upwards so it left view just a few moments into the flight.
Ed Fendall was the person doing the controlling. In an oral history for NASA done in 2000, he recalled how complex the procedure was.
Now, the way that worked was this. Harley Weyer, who worked for me, sat down and figured what the trajectory would be and where the lunar rover would be each second as it moved out, and what your settings would go to. That picture you see was taken without looking at it [the liftoff] at all. There was no watching it and doing anything with that picture. As the crew counted down, that's a [Apollo] 17 picture you see, as [Eugene] Cernan counted down and he knew he had to park in the right place because I was going to kill him, he didn't — and Gene and I are good friends, he'll tell you that — I actually sent the first command at liftoff minus three seconds. And each command was scripted, and all I was doing was looking at a clock, sending commands. I was not looking at the television. I really didn't see it until it was over with and played back. Those were just pre-set commands that were just punched out via time. That's the way it was followed.