You would not know from the calm atmosphere in Mission Control Centre here that a battle is raging outside over whether an astronaut, Mr David Wolf, should be allowed to join what some are calling a "suicide mission".
A decision is to be taken today on whether the US astronaut will blast off from Cape Canaveral on Thursday to re-supply Mir. In Mission Control a training run was in progress and the huge screen showed Atlantis successfully docking with Mir.
The doubts are over the wisdom of allowing Mr Wolf to risk his life by spending the next few months in the 11-year-old, disaster-prone Russian space station.
In interviews at the weekend, Mr Wolf rejected suggestions that he was going on a "suicide mission". He said: "We're very well trained to handle any reasonable emergency . . . I'm ready to go. I feel very good about the mission and the goals."
But in Washington Mr Frank Culbertson, a former astronaut who manages NASA's joint space programme with the Russians, was being grilled before the congressional science committee. Many members believe that further stays on Mir for US astronauts are an unacceptable risk.
Mishaps on Mir since February include a fire, a supply ship crashing and damaging solar panels, several power black-outs and computer failures. The Russian cosmonaut in charge suffered heart problems for a while.
NASA is being accused by critics of allowing its judgment to be clouded by its vested interest in allowing the US astronauts complete seven planned missions on Mir. These are a preparation for the international space station (ISS) involving 15 nations which will start being assembled next year.
The independent NASA inspector-general, Ms Roberta Gross, who has assessed Mir's safety, says the individuals at the Johnson Space Centre (JSC) might be too closely involved to measure the safety problems.
NASA employees were labelled "whiners and alarmists" if they raised concerns about the space missions, Ms Gross said. Astronauts feared they would jeopardise future trips to space if they voiced reservations.
The director of NASA in Washington, Mr Dan Goldin, has ordered one more evaluation from former astronaut Mr Tom Stafford, before giving the final goahead for Mr Wolf to replace his colleague, Mr Michael Foale, who has been in Mir since May.
Mr Foale has said the Mir problems made his experience there the most difficult of his life but insisted that "out of this co-operation of America with Russia, which is not always easy, we are achieving some extremely great things".
The Russians fear that the US may be getting ready to back out of its partnership on Mir, to which it contributes almost $500 million. A Russian space official, Mr Valeri Ryumin, warned last week that if the US withdraws from Mir the Russian parliament may seek to get out of participation in the ISS for which Russia is building the Functional Energy Block to be launched next year.
At the space centre I was able to walk around the full-scale mock-up of the ISS used to train the future seven-member crews. It will take 45 space flights to assemble the 262 ft long and 356 ft wide ISS, which will be orbiting 220 miles above the Earth early next century, sending back scientific results from its six laboratories.
In the same building as the new Mission Control Centre, with its digital displays and electronic consoles, is the centre which oversaw the first landing on the moon on July 20th, 1969.
It was in the living room of a suburban semi-detached in Blackrock that I heard the fateful first words from the moon: "Houston, Tranquillity Base here. The Eagle has landed."
Now here was the room where those words caused an eruption of joy over the achievement of putting the first men on the moon. It was like looking at a deserted second World War airforce base.
The old black-and-white TV consoles, which had no software and had to be rewired for every space flight; the steel desks, the blank, wall-sized screen with its dark background nicknamed "the bat cave" and the old-fashioned pneumatic tube message system "which always worked", former flight controller, Mr Henry Allen, said nostalgically.
From that room, soon to be restored to its original appearance as an exhibit, went the response to the men on the moon:
"Tranquillity, we copy you on the ground. You've got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."
To think that was 28 years ago.