Earth. Photo: NASA

Jim Lovell, Fred Haise and Jack Swigert are now so accurately on course for their 75-hour flight to the moon that their first mid-course correction has been cancelled. Clearly, the re-constituted crew is settling down well together. As Commander, Lovell, responsible for punching the Abort Button if anything went wrong during lift-off, had a heart beat then of 116; while his two crew members, neither of whom had been in space before, registered only 102.

Swigert won warm praise from Mission Control for the way he completed the transposition and docking manoeuvre -- extracting the Lunar Module from the Saturn 4B rocket stage, so that it's now on the Apollo spacecraft's nose -- and also for the accuracy of his celestial navigation.

Lovell several times inquired why it was that the centre engine of Stage Two had shut down two minutes early during launch, but was told that so far no one knows.

The third stage of the S4B, now separated from Apollo 13, and which is to be deliberately crashed on the moon so that the Apollo 12 seismometer can measure the impact, is on a less accurate course than the spacecraft. For that, course corrections are being made, and it should bury itself in the face of the moon while Apollo 13 is out of sight behind it on its first lunar revolution .

With this flight now as confidently under way as the previous six in the series, Captain Lovell's wife Marilyn, flanked by her two sons and two daughters, ranging from 16 to 2, held her own post-launch news conference here. For her, each spaceflight gets harder, she said. She was selfishly delighted that this fourth mission would be her husband's last. I asked her what she thought about the Apollo 13 crew having to undergo three weeks' quarantine when they get back, despite previous findings that there was no lunar life likely to contaminate earth. "I'm sure they have good reason," she said, "but personally I think it's ridiculous!"