45 years of manned spaceflight
Published on Apr 12, 2006 at 6:19 pm.
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Forty-five years ago, a massive rocket, basically a modified R-7 ballistic missile, roared to life at Bailonur. The R-7 was the Soviet Union’s first long range ballistic missile. It consisted of a central tube with four strap on boosters around outside of the bottom of the central tube, giving it a sort of tapered shape, rather like a metallic Christmas tree.  Propellant for the R-7 was refined kerosine and liquid oxygen. The R-7 was designed to carry a 5 metric ton thermonuclear warhead. However, on April 12, 1961, this R-7 held a small sphere on top that resembled a bathosphere. Inside this sphere was Yuri Gagarin. The spacecraft was Vostok 1. Gagarin was basically along for the ride. In fact, his controls were locked so that he could not assume control of the spacecraft. In an emergency he could be given a key to enter into the instruments to assume command. However, this would be an extraordinary situation. For all practical purposes, he had as little control of his spacecraft as Laika, the dog that flew on Sputnik 2. The flight was successful, with Gagarin making a complete orbit of the Earth in a little over an hour and a half. The Vostok capsule was not designed to safely land with the cosmonaut on board, so he ejected when the craft was at a safe altitude and floated down by parachute. The R-7 missile was not a good design for an ICBM: it took too long to fuel and prepare for flight. However, it was a fantastic booster to lift payloads into space. With some modifications, the R-7 flies today as the Soyuz rocket. All manned Soviet and Russian space missions, Vostok, Voskhod, and Soyuz, have lifted on some variant of the R-7 rocket. This is a fantastic tribute to Sergei Korolev’s rocket design. It is still in use 45 years later supporting missions to the International Space Station.Â
On can argue that manned spaceflight began some time prior to April 12, 1961, because planning for this flight can be traced as far back as the 1950’s. Even Wernher von Braun was thinking of manned spaceflight in the 1940’s.  However, Gagarin’s flight was the first successful manned mission.Â
The Soviet Union, though, was not the only nation working to put a man in space. On May 5, 1961, Alan Shepard rode a capsule named Freedom 7 on a quarter hour flight from Florida to the Atlantic Ocean in a large parabolic arc to become the first American in space. The Redstone rocket that launched him was nowhere near powerful enough to lift a load as heavy as a capsule into orbit. That required an Atlas rocket. The problem with the Atlas, though, was that it tended to explode when launched. Those bugs had to be worked out before John Glenn could ride Friendship 7 into orbit on February 20, 1962. By this time, both nations had set eyes on the Moon. The Soviet Union began development of the Soyuz spacecraft and the massive N-1 rocket to launch a vehicle to the Moon. The United States began work on Apollo and the Saturn V rocket. The Saturn V, a massive rocket nearly as tall as a 40 story building, was the largest operational rocket ever built. When it launched, all of Florida and Georgia shook. However, as big as the Saturn V was, it still was not large enough to lift a spacecraft large enough to land on the Moon and return to Earth. Instead, a small lander would separate from a mother ship to land. The lander would then lift off and rendezvous with the orbiting mother ship, which would then return to Earth. This meant that spacecraft had to be able to find each other and dock in orbit. Also, no one knew if astronauts could live that long in space, without the feel of the gravitational pull of Earth on their bodies. So, Project Gemini was born. Gemini perfected the skills needed for piloting and docking spacecraft. Gemini provided valuable data on long duration spaceflight. Gemini provided the opportunity for the first spacewalks.  So, when Apollo came, NASA had plenty of practice in space. However, budget issues cut Apollo short. The last three missions to the Moon never flew.
The United States had won the space race. Now, what? What was to come next? It would be a shame to shut down NASA, put away all our rockets and spacecraft, and go home. Surely, the justification for going into space was more than just beating the Soviet Union, right? Well, along the way, other reasons for space exploration were soon found. Satellite communications, at first a novelty, grew to become a major fixture of society. The military began to rely on satellite surveillance, communications, and navigation.  Scientists and engineers realized that materials behaved differently in low gravity environments, paving the way for space research. It was no surprise that a manned space station should be in the plans.Â
The Soviet Union beat the United States to orbiting a space station with Salyut 1, launched April 19, 1971. Salyut 1 was a fairly small structure with simple living and work spaces, however it paved the way for later space exploration. Salyut 1 was followed by six more Salyut class stations, with Salyut 7 being launched April 19, 1982. Then, the Soviet Union launched Mir. The Mir space station started as an improved Salyut, but then more sections and modules were added, and numerous spacecraft came to call on Mir over its decade long life, including not only Soyuz craft, but also the American Space Shuttles, making Mir truly into a modular space station. However, we can’t overlook the first American space station: Skylab. With the last three Apollo missions cancelled, NASA had three Saturn V rockets left over. The upper stage of one was adapted to become Skylab, the first American space station. Three cycles of astronauts visited Skylab using Apollo capsules launched atop smaller Saturn I-b rockets. Skylab proved the value of space-based research.
With the end of the Apollo program, NASA had to select a new mission. Originally, plans called for a permanently manned Earth orbiting space station, a permanently manned Moon base, and a mission to Mars. All this was to be done by the end of the 20th Century. Given how quickly space exploration had gone from Sputnik to landing a man on the Moon just over a decade later, this seemed a realistic goal. However, the lack of sufficient budget kept this from happening. NASA got a space shuttle. The shuttle that was built was a scaled down version of what they wanted, together with a load of compromises. The Space Shuttle was planned to be a cheap and efficient way into space. The need for inexpensive access to space was obvious. We were increasingly dependent upon satellites, but each satellite launched took a multi-million dollar rocket. Also, several satellites were doomed by very simple failures that could easily be fixed on Earth, but not remotely. Also, plans were still on the books to build a space station. So, the Space Shuttle was supposed to be a bridge between Apollo and the next generation of spacecraft. To cut costs, the Space Shuttle was supposed to be reusable. Originally, all parts were to be reusable multiple times, but soon it was decided to expend the external fuel tank. After the Challenger accident, it was decided that the solid rocket components were not to be reused to the extent that had originally been planned. Also, to make the Shuttle efficient, there had to be one to two shuttle flights per week. This never materialized. Furthermore, the Challenger accident showed that what many had forgotten: the Space Shuttle, as a first generation reusable spacecraft, is an experimental vehicle. All the bugs have not been worked out. Prior to the Challenger accident, the Space Shuttles had begun to be used to deliver satellites to orbit, to retrieve satellites for repair, and to conduct microgravity experiments in orbit. After the accident, though, President Reagan issued a directive that the Space Shuttles were not to be used for missions that did not require manned spaceflight. In other words, if a mission could be performed without risking human life, then do it that way, ignoring cost. So, post Challenger, the Space Shuttles lifted a small backlog of satellites into orbit that had been designed for delivery by space shuttle, but future satellites were delivered by unmanned rockets. The Space Shuttles continued to do science missions, and they did servicing missions to the Hubble Space Telescope. However, the number of missions dropped to about six per year. Furthermore, after each mission, the orbiter was gone through with a fine tooth comb, so turn-around began to be longer and longer. It became impossible for the Shuttle program to make money or be cost effective under such conditions. In fact, as unmanned spacecraft became cheaper and more reliable, then using a Space Shuttle to launch a satellite came to even cost more than using an unmanned rocket! The Space Shuttle continued to fly missions up to two weeks in length to study the effects of microgravity in various experiments. Thus, the shuttles were being used as temporary space stations rather than as “shuttles.”
After the first few test missions, the Space Shuttle fleet was delivering satellites into orbit, one of its original purposes, but that stopped after the Challenger accident. The science missions were part of the original idea, as well, but one of the biggest plans for the Space Shuttles was to carry astronauts, equipment, and components to a space station. The only problem was that we didn’t have a space station. Eventually, however, on June 27, 1995, the Space Shuttle Atlantis blasted off on mission STS-71 to dock with Mir on June 29. This was the first visit of a Space Shuttle to a space station, and it wasn’t an American space station. Eight other Space Shuttle missions went to Mir.  The original plans for an American space station, Space Station Freedom, never materialized. Freedom was to be the United States response to Mir. However, with the cold war ending, and then the fall of the Soviet Union, plans for Freedom were shelved. Instead, the United States decided to cooperate with the Russians on working with Mir, with a module dedicated to the Americans being added to Mir.
However, Mir had reached the end of its life. The United States, Russia, and several other nations agreed to fund an international venture. This became the International Space Station. Unfortunately, the economy of Russia was collapsing, so funding for the ISS largely fell to the Americans. The first component of the ISS was launced by Russia in November 1998, followed shortly thereafter by the delivery of the first American component by the Space Shuttle Endeavour in December 1998. Ten other space shuttle missions followed, each delivering components, supplies, and crew rotations. Unfortunately, the loss of the Columbia has had a major impact on the completion of the ISS. Without a crew escape vehicle other than a Soyuz, the crew of the ISS is limited to 3, and it takes 2 to run the space station, leaving only one to do science experiments. However, the Progress modules are not sufficent to provide supplies for a crew of three, so the crew has been limited for the last couple years to two. The ISS has been largely in a holding pattern, waiting for the return of the Space Shuttle to active duty. This has been a great disappointment. Many in the space community think of the ISS as a budget black hole for NASA. Keeping it flying is costing other programs, and keeping it flying has produced nowhere near the rewards that we had hoped due to the lack of shuttle support.Â
We don’t have a moon base. We have not had a manned mission to Mars. We barely have a space station, and it doesn’t really do much at the moment. We have a lot of satellites, of course. But, manned spaceflight seems to have gotten nowhere as far along as we had hoped when I was young.  This is sad.Â
-Astroprof
