When I was a young child (around 9 or 10 years old I think) my favourite series of books was about a young astronaut from the UK who becomes the first human in space. That's the plot of book one. In subsequent books, this boy (a precursor of Alex Rider?) joins up with friends from other nations in a combined space programme. They go to the Moon and, in each subsequent book, the other planets of the Solar System, having numerous adventures on the way.
I have long since forgotten the details of these books, but remember how much I enjoyed them and what an impression they made on me. I made a half-hearted attempt to search for them (after combing the shelves of many bookshops in vain) when my own children were the age I was when I read them, but could not find them. I recalled the names "Chris" and "Hugh", and that the rockets always blasted off from Woomera, Australia - but that was not sufficient for me to track down the novels. Nobody else I knew among various science-fiction fans could recall these books either.
The other day, I mentioned this story to Karen of Euro Crime and, lo and behold, based on my skimpy description she rapidly uncovered the books' identities! Brilliant. (And one up for librarians, of course.) The books are by Hugh Walters, and are listed here at Fantastic Fiction. Although they are not available apart from expensive collectors' or second-hand editions (and not in all cases), they can all be found at Amazon. The (UK) Amazon page of the first novel, Blast Off at Woomera, has a customer review by I. J. Parnham providing a synopsis of all the books, which brings back such fond, happy memories of a fantastic scientific adventure series. As an aside, Hugh Walters was from the Midlands of the UK, so his novels are often set around Dudley, where he went to school. Here's an ordered list of the series, with some brief descriptions (links go to entries on the author's website):
1. Blast off at Woomera: "Mysterious domes have been sighted in a crater on the Moon. Suspecting that they may be the work of Communists, the British Government must launch a man into space in order to photograph them from outside the atmosphere. Unfortunately their rocket was not designed to carry a man, and so someone unusually short is required. Enter Chris Godfrey, a four foot ten and a half sixth-former at Wolverton Grammar School. Will he survive the trip? The less than reliable rocket is to be launched from Australia - but there may be a Soviet traitor among the ground crew!"
2. The Domes of Pico : "The alien domes on the Moon are radiating a strange form of energy, which is neutralising all the nuclear power stations on the Earth. Chris Godfrey's task is to pilot a rocket and plant a homing beacon next to the domes, which will be used to target a nuclear missile strike. The commander of the mission, Sir Leo Frayling, is determined that the mission will succeed - even though the cost may be Chris' life!"
3. Operation Columbus : The Soviets and the Americans hate losing out to the Brits on being the first to do everything in space. Both nations are determined to plant their flag on the moon. Serge Smyslov and Morrison Kant are the respective astronauts who team up with Chris....
4. Moon Base One : There is now a united world space programme. Chris commands a mission to the moon to find a cure for the radiation sickness mentioned earlier with Serge, Morrison and new addition Tony Hale.
5. Expedition Venus : An unmanned probe descends into Venus's lush jungles and brings back a slime sample which becomes a danger to Earth. The astronauts aim to go to Venus to find an antidote.
6. Destination Mars : Mars is outside the Van Allen belt and anyone straying beyond it goes mad. Chris leads a mission to Mars to find out why.
7. Journey to Jupiter : Chris and his friends are in trouble when it turns out that scientists have miscalculated Jupiter's gravitational pull on their space ship.
8. Mission to Mercury. Girl astronauts! Telepathic twins!
9. Spaceship to Saturn. Computers!
10. Mohole Mystery : An Earth-bound adventure for the astronauts.
11 Nearly Neptune : Cryogenics!
12. First Contact? : Mysterious radiation and friendly (?) aliens on Uranus.
13. Passage to Pluto : Chris is too old to fly so is now head of the united world space programme. His friends go without him to find out why Pluto has a weird orbit. What they discover signals danger for the whole Solar System.
Apparently the novels did continue after book 13 with Tony Hale as the main character, but I did not discover these - I was happy to leave them at the stage I did, whereupon I probably graduated immediately to John Wyndham, whose books I rapidly devoured. I then graduated to reading every science-fiction book in the local library at the age of 14 or 15, whereupon I stopped reading this genre in its entirety, and have not returned to it since, apart from a very occasional reversion (First Contact by Carl Sagan, for example).
More information: Hugh Walters (the author) at Wikipedia.
Hugh Walters's website, which states "Unfortunately the books have been out of print for many years, and many libraries have now disposed of their copies." The website has a page for each novel, with a brief description, commentary, bibliographic information, and pictures of the covers of various editions of each. Obviously, from the descriptions, these novels are considerably dated now in attitude as well as in scientific, political and other ways, but I bet they would still be considered very good reads by the target age-group, even so.