And this is actually one of the slightest stories of all. There's a small mystery about what's happened to Calculus and just where Tintin, Snowy and Captain Haddock are being taken. Later there's the odd moment where a plot by an unnamed foreign power interferes with the plans but overall this tale isn't advancing the story. Instead it's showing in great detail the preparations for a grand expedition.
This story is very much Calculus's affair and he dominates proceedings. As often happens with recurring fictional scientists, he is now an expert in whatever the particular story requires. Here he has been leading a project for exploration of the Moon. The original publication of this story preceded all the developments in space travel and so represented up to the minute scientific developments and a post war optimism about the future. Even space science fiction was only slowly developing with the US film Destination Moon (the same name is only used in the English translation) coming out midway through. In spite of the presence of Tintin, Snowy and Haddock, this is an exploration driven by scientists not explorers and it shows.
At times the story can seem almost too keen to show its commitment to scientific accuracy. We get explanations of how nuclear fission works, a whole sequence with an exploratory rocket that circles the moon for the first time and then a steady construction of another rocket to carry human explorers. All this takes time and the album is careful to show events unfold over many months, with even the rarely glimpsed enemy spies also being shown to be highly patient. Some of the explanations can get a little heavy but much of the key information is delivered by Calculus in a fast-paced scene where he gets outraged at being accused of "acting the goat" by Haddock and proceeds to drag him to the rocket to show every single level and explain its purpose. The humour of the normally mild-mannered scientist furiously proving his critic wrong means that this scene never drags and instead establishes him as a great explorer of knowledge.
Hergé takes care to keep the story as realistically rooted as possible. The key breakthroughs are the invention of a nuclear motor and the discovery of "calculon", a new alloy able to withstand the extremely high temperatures generated. Although the name itself smacks of fictional scientific egotism, both the actual inventions are sufficiently believable and drawn from contemporary developments that they never feel like fantastic creations for the sake of it. The spaceships themselves (there are actually two) would have also struck a contemporary readership as plausible, being based on the German rockets from the Second World War. Of course, in the time since publication spaceship development has gone in a different direction with most spacecraft, including the Apollo series, coming in a modular form that cannot simply be refuelled and reused. Still this different direction should not be held against this story which stands up as some of the hardest science fiction seen in the whole series.
There are only a handful of areas where the story seems to be making concessions to narrative. The space suits shown in development have clear transparent helmets (made of a substance called "multiplex" in an era when that word was not so widely known for other things) which allows the characters to be identified. There's also the surprising willingness to accommodate Snowy, right down to making special radiation and space suits for him, thus maintaining his position in the series at the expense of realism. Also, we don't see any particular sign of training the eventual astronauts for the conditions of space and as late as just before launch there's a suggestion of sending up the institute's director instead. The setting is Syldavia, the country previously seen in King Ottokar's Sceptre, which has recently become enriched by the discovery of uranium deposits. It feels a little odd that such a small hidden country would be pioneering space exploration given the costs involved. Then again there's almost nothing in this story recognisable from the previous tale - a one panel appearance by Colonel Jorgen - and it could have just as easily been set in just about any country. Given the previous resort to a combined western European expedition in The Shooting Star it's actually a surprise that such international co-operation was not repeated yet at the same time there's no overt sign of the country trying assert national pride or punch above its weight through this. We never learn Frank Wolff's nationality so at most there may be just a single Syldavian on board.
That doesn't mean the expedition isn't of wider interest and the result is a high degree of espionage and security. At the start of the story Tintin, Snowy and Haddock are subject to a complex series of manoeuvres as they are taken from the airport to the complex, whilst later on spies try to infiltrate the base and steal the plans. A rival group goes so far as to jam the radio of the initial observer rocket and divert it of course with its secrets; however Tintin and Calculus have been prepared. A search in the mountains outside reveals papers are being smuggled out. The investigation is complicated rather than helped by the arrival of Thompson and Thomson, who for once cannot even get the right national dress. As a result, there's a consistent effort to avoid further theft and sabotage, whilst from time to time we see glimpses of the rival operation. It all helps to build up the tension.
Then comes the ending of the tale as the rocket blasts off with Tintin, Snowy, Calculus, Haddock and Wolff on board - but then it refuses to respond to ground signals. This is by far the strongest cliffhanger of any of the two-part Adventures, putting the characters in an actual dangerous situation with a question mark over their fate rather than merely declaring that they will go to another location for the continuation of the story.
This is an album without the most developed of stories, since it is unapologetic about being the first part that is setting things up for the conclusion in a much more overt way than previous two-part adventures. But that does not detract from a bold and imaginative approach that shows a high degree of confidence in the series as it enters the 1950s. The start of the Space Age was on the horizon and this album successfully anticipates what was to come whilst also providing one of the series's best known icons. This is one of the best of all The Adventures of Tintin.