Moreover, all technical and transportation cost extrapolations are based on the Shuttle development experience (in 1980) and assume 100% reliability. Space Shuttle operations during the past decade have shown dramatic and unexpected technical limitations (97% reliability, TPS damages, relatively low reusability and high maintenance costs) and significant cost overruns : 5330 (1980) US Dollars/kg of payload for 100 predicted in 1980. Today's current prices for large launchers range from 1000 (with Energia) to 9000 (with Titan 4) (1990) US Dollars/kg of payload. These figures must be compared to the Boeing estimates of 25 (1980) US Dollars/kg of payload with the Reference HLLV! 8.4.3 Previous Heavy Launchers Introduction Why must we review previously heavy launchers? A couple of reasons account for this necessity. First of all, we should reaffirm numerous problems that previous launchers had suffered from and its solutions not to come across the same problems. Even if we come across a new issue, reviews of previous heavy launchers may give us the first step to solve it. Particularly in developing a new transportation system, reviews may show us any facts to be considered. Secondly, we can not throw away the previous technologies only because it is old fashioned. Table 8.7 shows payloads of various lineage, launch masses and various historical launchers. In the following part the Saturn family and the G-l-e launcher are described in more detail. The Saturn Family (United States) The Saturn program came from Dr. Werner von Braun's proposal in April 1957 developing a launcher capable of placing payloads between 9,100 and 18,200 kg into a low Earth orbit. The Saturn I consisted of the S-IB first stage, S-IV second stage, and Instrument Unit (IU) and it carried payload up to 10200 kg into east LEO. The S-IB first basic design concept incorporated Jupiter and Redstone components because of their reliability and qualification status. The enlargement and refining of the S-IV stage design and the replacement of six Pratt & Whitney RL10 engines with a single Rocketdyne J-2 engine, produced the S-IVB stage used on the Saturn IB vehicle. This improvement within two years, made it to increase the payload delivered into a LEO up to 16600 kg. On top of this ability Saturn IB can escape payloads of 4,300 kg from the Earth Orbit. The Saturn IB was used to develop and test Apollo hardware and software in rehearsal for lunar mission with the Saturn V. Only 21 months after the first flight of Saturn IB, February 26 1968, Saturn V was launched. The payload capacity placing into LEO was increased orderly up to 119000 kg as compared to 16600 kg for the previous Saturn IB. Also payload escaping from the Earth Orbit was increased up to 50,000 kg. To our surprise, conservative Saturn design margins enabled the launch of the last three Apollo missions although 13% more performance was needed than ordinary required. This was a remarkable progress. In the present situation a similar progress looking at the space transportation in the United States cannot be recognized. It is due to some disadvantages of the US. space shuttle concerning its unreliability and unavailability. Even after 10 years of operation, the space shuttle still suffers from chronic technical difficulties and record of repeated flight delays. G-1-e Launcher (Soviet Union) The G-l-e (113m length, 17m in diameter at the base, and 30 engines for the first stage creating a total thrust of 45 MN) was designed to support the Soviet lunar program. The vehicle was designed by Sergei Korolev. With three stages the rocket reaches Earth orbit. The two top stages were used for trans-orbit injection. A factor which may have been more than a little responsible for significant development delays and four launch failures could have been the choice of inexperienced rocket engine manufacturers. In fact, the G-l-e had been test flown only once, on 21 February 1969 when it suffered an explosive failure at an altitude of 12200 m. The second flight was a rehearsal mission whereby a 3-man Soyuz would dock with the G-l-e in orbit. However, on 3 July 1969, before the Soyuz launch, the G-l-e failed again. This accident sounded the death knell for the Soviet lunar program, even though the Soviet tried twice more to prove their G-l-e in 1971 and 1972. Both flights ended in failure. In the 1971 flight, the vehicle developed an uncontrolled roll seconds after liftoff. The on-board computer shutdown the engines and the G-l-e stack again collapsed back, completely destroying the second pad and gantry, which had been badly damaged in 1969. The last 1972 flight almost made into first stage cutoff. Staging had begun when the first engines were shutdown. Suddenly, a longitudinal pogo
RkJQdWJsaXNoZXIy MTU5NjU0Mg==