"You'll never forget it, not all your lives!" says Ruby and Cedar's mum as she gets them up in the middle of the night to watch the moon landings. It's the fiftieth anniversary of that epoch-defining event this very weekend - and inspired by it, Fishhouse Theatre have created a gem of a show, that celebrates a love of space, sisterhood, and friendship.

The two sisters, "Irish twins" born within a year of each other, are inspired to meet every year on the anniversary of the moon landing for the rest of their lives. The elder, Ruby, is obsessed by space as a child, and can’t wait to get away from home and on to her stellar career. Cedar's tastes are more earthy, and she stays at home, raising children and looking after their mother.

Ruby and Cedar are also the code names of Soviet Cosmonauts Komarov and Gagarin - the latter famous as the first man in space - and like the sisters, they’re close friends and rivals. The story of the first Soyuz mission is told in parallel. Both cosmonauts know the programme is deeply flawed, and the reserve Gagarin tries to bump Komarov from the flight, fearing for his friend’s life and knowing the Soviet Union would never risk him as a national hero.

Yet the core of the play is the sisters’ relationship, which is beautifully portrayed through the years by Blue Merrick as Ruby and Therese Collins as Cedar. Any siblings will recognise the dynamics in the gorgeous play sequences: the elder leading, the younger following, a firm hand off from big sister if she looks like stepping out of place. As they get older the dynamics change. Cedar is interested in boys and sex, and teases the more intellectually focussed Ruby, while later Cedar remains at home - tied down like Gulliver by the tiny strings of family commitments.

Alongside these twin stories, we also discover the tale of Valentina Tereshkova, the first woman in space who orbited earth for three days. I understand the desire to include this story of female space endeavour, but it did lead to some confusion towards the end, when it became difficult to distinguish between Komarov’s and Tereshkova’s tales.

One welcome aspect to Fishhouse’s productions is that by having a space all to themselves at the Lee Wood Hotel, they are not constrained by having a set that must be set up and taken down in minutes. Lydia Denno’s creation for Ruby and Cedar is excellent, the suburban garden hinting at space in its use of circles. The use of the sun loungers in play-time lift-off is delightful, and I loved the helmets!

Writer Alison Dunne has produced another thoughtful play, and Fishhouse seem able to access a tenderness in their work seemingly unavailable to many others. Their shows are always full of heart, and Collins’ face in the final touching scenes will live long in the memory.