Page Content (OCR)
lift the PEPP vehicle to 130,000ft (39,624m) using the biggest balloon ever constructed and, four seconds after release, to fire the rocket motors to accelerate the vehicle on an arcing trajectory that would reach approxi- mately 160,000ft (48,768m) and peak at about Mach 1.2. Although the release from the bal- loon was controlled using a ground com- mand, there was no telemetry transmitted from the onboard instrumentation because this was considered an unnecessary compli- two large control surfaces along the trailing So the only easy way to undertake atmos- edge and a substantial tailfin allowed control _ pheric entry simulations was at extreme alti- during descent and landing. At the centre of _ tude, either using a rocket or a balloon to the vehicle’s underside was an area that carry the test vehicle toa suitable height. With appears to be a bomb bay and there was a __ the operational details decided, test vehicles fully retractable undercarriage consisting of _ were designed and built by NASA Langley four struts, each equipped with six wheels. under a project called the Planetary Entry Liquid-fuelled rocket engines powered the — Parachute Program (PEPP), which was man- spacecraft and fuel would be stored in tanks — aged by John C McFall. that follow the circular shape of the vehicle. The first PEPP vehicle (also referred to as a No doubt the Russians intended to use this flight unit) took the form of a 15ft (4.57m) craft at times of crisis as a flexible delivery sys- | saucer-shaped disc carrying various instru- tem for nuclear-tipped space-to-ground mis- mentation packages and a parachute pay- siles, or for global reconnaissance missions. load. Weighing 1,600Ib (725kg), it was Crew numbers and the mission duration are — equipped with a ring of twelve small Falcon unknown although the option of an TX-18 solid-propellant rocket motors, each unmanned version was considered. producing a thrust of 3,4001b (1,542kg), that The Russians studied several different would burn for 1.5 seconds. The idea was to cation. The first launch took place 30th August 1966 at Walker AFB, Roswell, New Mexico and the test vehicle was lifted by a massive 800ft (244m)-tall helium-filled balloon with a 26 million ft' (736,238 m*) capacity that was specially fabricated by G T Schjeldahl Co. As The Russians studied several different would burn for 1.5 seconds. The idea was to _ specially fabricated by G T Schjeldahl Co. As mothership concepts with various cockpit — = 7 and engine layouts. Drawings show two large ak T Zi 4 fins on the upper and lower surfaces of the disc and either two or four liquid fuel rocket engines, often supplemented by a pair of tur- bojets. One design for a launch craft had a bullet-shaped cockpit protruding from the front of the disc, perhaps to facilitate improved visibility or allowing it to be used as an escape capsule. This Ilyushin mothership was also considered as a long-range high- altitude bomber or transport aircraft, usually powered by eight jet engines. It is very unlikely that any of these concepts pro- gressed much further than an elementary design stage but the project is believed to have remained active until the end of the 1970s. Planetary Aeroshell Trials During the early 1960s, NASA’s Jet Propulsion Laboratory at Pasadena, California started Planetary Aeroshell Trials During the early 1960s, NASA’s Jet Propulsion Laboratory at Pasadena, California started looking at ways to soft-land a robot spacecraft on Mars. Known as Project Voyager this ambi- tious project would later be re-named Viking, with the title Voyager being re-assigned a robotic grand tour of the gas giants Jupiter, Saturn, Uranus and Neptune. But testing hardware for the Mars mission proved very difficult because the planet’s carbon dioxide atmosphere was found to be far thinner than scientists once believed. This was discovered on 14th July 1965 when NASA’s Mariner 4 probe passed behind Mars and radio signal occultation showed that atmospheric density at the surface was less than one per cent of that found at sea level on Earth. Above right: Type 1 PEPP aeroshell showing the 12-rocket motor installation. NASA Right: Type 2 PEPP aeroshell on display at White Sands Proving Ground. NASA 129 Above right: Type 1 PEPP aeroshell showing the 12-rocket motor installation. NASA Right: Type 2 PEPP aeroshell on display at White Sands Proving Ground. NASA Flying Saucer Spacecraft