Starman_ The Truth Behind the Legend of Yuri Gagarin - Jamie Doran [84]
With every intention of making his mark at Zhukovsky, Gagarin selected for his thesis nothing less than the holy grail of manned space flight: a practical design for a reusable winged space plane. Alexei Leonov, who studied with him for several months, recalls, ‘He was very strict with himself. I was always amazed how conscientious he was about his studies, how thoroughly and painstakingly he prepared his work, and how hard he tried to keep up with the others. Somebody who was full of airs and graces wouldn’t have put himself through all that.’
Obviously a spaceship with wings could come home in an orderly fashion, landing at an airbase instead of falling down into a ploughed field or splashing into the sea. The wings would slow and control the final descent, so that the ship could touch down softly on wheels. Unlike the clumsy space capsules, a winged craft could be refurbished for another flight. The difficulty was to balance the aerodynamic usefulness of wings with the need for bulky re-entry heat-shielding. NASA had already started work on so-called ‘lifting bodies’, experimental craft that were neither capsules nor aircraft but something in between. They were dropped at great altitude from beneath the wings of B-52 bombers, and most of them landed successfully. However, it was impossible to send them into space because the addition of rocket engines and fuel tanks would have made them too heavy; and there was the intractable problem of the heat-shielding. At that time no sufficiently strong and lightweight material seemed capable of protecting the lifting body’s stubby wings against melting away during re-entry. The ‘ablative’ heat-shielding of conventional capsules was thick and heavy, and it burned away irretrievably, leaving terrible scars on the capsule’s flanks. The bulky resins and fibres used for the shields were completely unsuitable for wings.
In all, the spaceplane presented the most complex technical challenge. Even the current NASA space shuttle is a flawed design, consisting as it does of heavy components and throwaway tanks, with clumsy ceramic tiles to protect it against the heat. The search is still on for a genuinely efficient design. For Gagarin to research into these issues in the mid-1960s was proof of his great seriousness in attempting to re-qualify for space flight. Today few people remember his engineering skills; only his simple farmboy’s smile. His painstaking and disciplined diploma work at the Zhukovsky Academy has been entirely forgotten except by his closest colleagues – in particular Sergei Belotserkovsky, the Deputy Director at Zhukovsky and the man who, more than any other, was responsible for the cosmonauts’ academic skills in space flight and orbital dynamics (while Kamanin and the specialists at Star City taught them how to operate the hardware).
One of Gagarin’s most significant achievements was to understand that, for safety reasons, his spaceplane had to be capable of an unpowered landing. Some of his tutors insisted that this was not technically possible. Gagarin argued that the spaceplane was useless if it could not make a ‘deadstick’ descent. After all, how could the crew get back if their engines failed? Just as for the Vostok capsules, a small braking motor should be enough to nudge the spaceplane out of orbit, he insisted; after that, it should be capable of reaching the ground without engines. His first solution was to bring the plane down by parachute, but of course that idea missed the point. Eventually he decided that it should glide to its landing. NASA’s modern shuttles do precisely that, with no use of engines during their final approaches.
In some crucial aspects, Gagarin’s thinking on the spaceplane concept outstripped that of his tutors; but on matters of strict aerodynamic science they pushed him hard. How would his spaceplane react to tail winds, head winds and cross