On the fourth day of the flight of Apollo 9, Schweickart felt better than expected as he worked his way into the lander to get it ready for the EVA. By the time he had put on the backpack, McDivitt was ready to let him do more – to stand on the lunar lander porch at least.
McDivitt later said that the engine had come on abruptly, but with the tremendous mass, acceleration was very slow – it took the whole 5 seconds to add 11 meters per second to the speed.
CAPCOM Number 1 (Deke Slayton): Okay. I think you ought to clearly understand there is absolutely no experience at all with landing without the helmet on.
SCHIRRA: And there no experience with the helmet either on that one.
CAPCOM: That one we’ve got a lot of experience with, yes.
SCHIRRA: If we had an open visor, I might go along with that.
CAPCOM: Okay. I guess you better be prepared to discuss in some detail when we land why we haven’t got them on. I think you’re too late now to do much about it.
SCHIRRA: That’s affirmative. I don’t think anybody down there has worn the helmets as much as we have.
SCHIRRA: We tried them on this morning.
CAPCOM: Understand that. The only thing we’re concerned about is the landing. We couldn’t care less about the reentry. But it’s your neck, and I hope you don’t break it.
SCHIRRA: Thanks, babe.
CAPCOM: Over and out
SCHIRRA: You’ve added two burns to this flight schedule, and you’ve added a urine water dump; and we have a new vehicle up here, and I can tell you at this point TV will be delayed without any further discussion until after the rendezvous.
CAPCOM (Jack Swigert): Roger. Copy.
CAPCOM 1 (Deke Slayton): Apollo 7, this is CAPCOM number 1.
CAPCOM 1 (Slayton): All we’ve agreed to do on this is flip it.
SCHIRRA: the first part garbbled then Schirra said… with two commanders, Apollo 7
CAPCOM 1- (Slayton): All we have agreed to on this particular pass is to flip the switch on. No other activity is associated with TV; I think we are still obligated to do that.
SCHIRRA: We do not have the equipment out; we have not had an opportunity to follow setting; we have not eaten at this point. At this point, I have a cold. I refuse to foul up our time lines this way.
Command Service Module-101 started through the manufacturing cycle early in 1966. By July, it had been formed, wired, fitted with subsystems, and made ready for testing. After the Apollo 1 fire in January 1967, changes had to be made, mainly in the wiring, hatch areas, and the forward egress tunnel. It was December before the spacecraft came back into testing. CSM-101 passed through a three-phase customer acceptance review; during the third session, held in Downey on May 7th 1968, no items showed up that might be a “constraint to launch.” North American cleared up what few deficiencies there were (13) and shipped the craft to Kennedy on May 30th 1967…
The key to high-energy stages was to use liquid hydrogen as the fuel. Liquid hydrogen fuel appealed to rocket designers because of its high specific impulse, which is a basic measure of rocket performance. Specific Impulse is the impulse delivered per unit of propellant consumed. You might think of it as the efficiency of the rocket. Compared to an RP-1 (kerosene) fueled engine of similar size, liquid hydrogen fuel could increase the specific impulse or efficiency of an engine by 40 percent. The combination of hydrogen and oxygen for propellants made the moon shot feasible.