The Demise of Mir

After several years of mishaps and close calls, the decision was made to discontinue
use of the Mir Space Station and to concentrate on the collaboration with the international community on the International Space Station. Early in 2001, the Mir Space Station was de-orbited and allowed to crash into the South Pacific Ocean. At 12:55 A.M. EST on March 22, 2001 (05:55 Greenwich Mean Time), the Mir station was 50 km (31 mi) above Earth’s surface. At 12:58 A.M. EST (05:58 GMT, 8:55 A.M. Moscow time) fragments of the station hit the ocean.
Alix Bowles, Project Coordinator for MirReentry.com watched the space station break into pieces as it streaked through the sky from a beach in Fiji. “It was a stunning blue steak followed by a sonic boom,” he said. “The pieces had a blue incandescence to them. There was something very peaceful about it,” he added. In its later years, the Mir station had become the butt of late-night television jokes, but, in fact, it was a productive scientific instrument and an important test bed for technology used on the International Space Station. Mir lasted years far longer than its designers had envisioned.

Skylab

On May 14, 1973, the United States launched its first orbiting space station, Skylab, designed to accommodate teams of astronauts to conduct a variety of experiments in geography, engineering, Earth resources, and biomedicine. Such work was carried out during 1973 and the beginning of 1974. In 1974, the craft’s orbit was adjusted to an altitude believed sufficient to keep Skylab in orbit until 1983, when a visit from the Space Shuttle was contemplated. At that time, the orbit would again be adjusted. Unfortunately, Skylab wandered out of orbit prematurely, in June 1978, and ultimately disintegrated and fell into the Indian Ocean on July 11, 1979.

Space Shuttles and Space Stations

The flight of Apollo 17 in 1972 was the last manned lunar mission, but not the end of the U.S. manned space program. On April 12, 1981, the first Space Shuttle, a reusable spacecraft (the previous space capsules had been one-shot vehicles) was launched. The Shuttle was intended to transport personnel and cargo back and forth from a manned space station, planned for Earth orbit. So far, Shuttle missions have carried out a variety of experiments, have delivered satellites into orbit, and have even repaired and upgraded the Hubble Space. In 1999, it started its most ambitious mission: the construction of an international space station, to be built in conjunction with Russia, Japan, and the European Space Agency (ESA). The realities of politics and economics mean that, in the twenty-first century, countries will be much more likely to cooperate in the race to space.

A More Distant Voyager

The Cassini-Huygens mission, a joint undertaking of NASA, the European Space Agency (ESA), the Italian Space Agency (ASI), and several other organizations, was sent on its way October 15, 1997, to investigate Saturn as well as Titan (one of Saturn’s moons). Some scientists believe that Titan might support life or, at least, offer conditions in which life could develop. The mission was named Cassini, in honor of the seventeenth-century French-Italian astronomer Jean Dominique Cassini, who discovered the prominent gap in Saturn’s main rings; and Huygens, after the Dutch scientist Christiaan Huygens, who discovered the Saturn moon Titan in 1655, as well as the rings of Saturn. It recently transmitted dramatic images of Jupiter as it sped past on its way to Saturn.

Mars Observer, Surveyor, and Pathfinder

Mars Observer, launched on September 25, 1992, was to conduct extensive imaging work while orbiting Mars, but contact was lost with the spacecraft on August 22, 1993, as the satellite was establishing an orbit around the red planet. It is possible that a fuel tank exploded, destroying the spacecraft. Mars Global Surveyor was launched on November 7, 1996, and is continuing a long project of (among other things) detailed low-altitude mapping of the Martian surface. Unexpected oscillations in its solar panels while coming into a circular orbit around the planet caused the start of the major surface mapping program to be delayed by almost a year.

Although the Global Surveyor project is extraordinarily ambitious, the public may have been more excited by the mission of the Mars Pathfinder. The craft was launched on December 4, 1996, and landed on Mars the following summer, using a combination parachute and rocket-braking system, as well as an air bag system to ensure a soft, upright landing. A “micro-rover” vehicle was deployed, which began transmitting extraordinary panoramic and close-up pictures of the Martian landscape. It is little wonder that Pathfinder has caused such a stir. We’ve always been fascinated by Mars, which, of all the planets, seems most like Earth and has often been thought of as possibly harboring life—even civilization.

Magellan, Galileo, and Ulysses

More recent U.S. planetary probes have been increasingly ambitious. Magellan was launched in May 1989 and ultimately placed into orbit around Venus. Using high-resolution radar imaging, Magellan produced images of more than 90 percent of the planet, yielding more information about Venus than all other planetary missions combined.
The spacecraft made a dramatic conclusion to its four-year mission when it was commanded to plunge into the planet’s dense atmosphere on October 11, 1994, in order to gain data on the planet’s atmosphere and on the performance of the spacecraft as it descended.
On October 18, 1989, Galileo was launched on a journey to Jupiter and transmitted data on Venus, the earth’s moon, and asteroids before reaching Jupiter on July 13, 1995, and dropping an atmospheric probe, which gathered data on Jupiter’s atmosphere. After an extended analysis of the giant planet, Galileo began a mission to study Jupiter’s moons, beginning with Europa. The so-called Galilean moons were discovered by the mission’s namesake, Galileo Galilei in 1610. The Ulysses probe was delivered into orbit by the shuttle Discovery on October 6, 1990. A joint project of NASA and the European Space Agency (ESA), Ulysses gathers solar data and studies interstellar space as well as the outer regions of our own solar system. Much of the spacecraft’s instrumentation is designed to study x-rays and gamma rays of solar and cosmic origin.

Pioneers and Voyagers

In the fall of 1958, Pioneer 1 was launched into lunar orbit as a dress rehearsal for the planetary probes that followed. The rest of the Pioneer craft probed the inner solar system for planetary information, and Pioneers 10 (1972) and 11 (1973) explored Jupiter and Saturn, the giants at the far end of our solar system. Later, in 1978, Pioneer Venus 1 and Pioneer Venus 2 orbited Venus to make surveys of that planet’s lower atmosphere and, using radar imaging, penetrated thick gaseous clouds in order to reveal the spectacular and forbidding landscape below.

Mariners and Vikings

The U.S. Mariner program launched probes designed to make close approaches to Mars, Venus, and Mercury. Mariner 2 (1962) and Mariner 5 (1967) analyzed the atmosphere of Venus. Mariner 4 (1964) and 6 and 7 (both 1969) photographed the Martian surface, as well as analyzed the planet’s atmosphere. Mariners 6 and 7 also used infrared instruments to create thermal maps of the Martian surface, and, in 1971, Mariner 9, in orbit around Mars, transmitted television pictures of the planetary surface. Mariner 10, launched in 1973, was the first spacecraft to make a close approach to Mercury and photograph its surface.
But even more exciting were the two Viking missions, launched in 1975. The following year, both made successful soft landings on Mars and conducted extensive analysis of the Martian surface.

The Apollo Missions

The data from the unmanned probes and orbiters was overwhelming in its volume and detail. Some critics continued to argue: Why send human beings? The manned missions clearly captured public attention, beginning with the Soviet Vostok series (1961–1963, including Vostok 6, which carried the first woman into space, Valentina V. Tereshkova) and the U.S. Mercury series (1961–1963). The Mercury series included two suborbital flights and the first U.S. manned flight in orbit, Friendship 7, commanded by John H. Glenn Jr., and launched on February 20, 1962.

(On October 29, 1998, 77-year-old Senator John Glenn boarded the Space Shuttle Discovery and became the oldest man in space. He returned from the mission on November 7.) The U.S. Gemini program came next, twelve two-man spaceflights launched between 1964 and 1967. The Gemini flights were intended very specifically to prepare astronauts for the manned lunar missions by testing their ability to maneuver spacecraft, to develop techniques for orbital rendezvous and docking with another vehicle—essential procedures for the subsequent Apollo Moon-landing program—and to endure long spaceflights. The eight-day Gemini 5 mission, launched August 21, 1965, was the longest spaceflight to that time. The Soviets also developed larger launch vehicles and orbiters. Voskhod 1, launched on October 12, 1964, carried three “cosmonauts” (as the Russians called their astronauts) into Earth orbit.

The U.S. Apollo lunar missions not only made up the most complex space exploration program ever conceived, but were perhaps the most elaborate scientific and technological venture in the history of humankind. Today, even if we had the desire, we no longer have the launch vehicles required to bring astronauts to the moon. According to the mission plan, a Saturn V multistage booster (rocket) would lift the 3-man Apollo spacecraft on its 21/4-day voyage to the moon, leaving behind the launch stages in pieces as it left the earth. After its journey, the small remaining piece of the initially launched craft would become a satellite of the moon, and the Lunar Module, with two men aboard, would separate from the orbiting Command Module and land on the moon. After a period of exploration on the lunar surface, the astronauts would climb back into the Lunar Module, lift off, and dock with the orbiting Command Module, which would fire its rockets to leave its lunar orbit and carry the three astronauts back to Earth.

After several preliminary missions, including Earth- and Moon-orbital flights, Apollo 11 was launched on July 16, 1969. On board were Neil A. Armstrong, Edwin E. “Buzz” Aldrin Jr., and Michael Collins. While in lunar orbit, Armstrong and Aldrin entered the Lunar Module, separated from the Command Module, and landed on the Moon, July 20, 8:17 P.M. Greenwich Mean Time.

“That’s one small step for [a] man,” Armstrong declared, “one giant leap for mankind.” And perhaps that sentence expressed the rationale for the effort, which went beyond strictly scientific objectives and spoke of and to the human spirit. Not that science was neglected. During their stay of 21 hours and 36 minutes, the astronauts collected lunar soil and moon rocks and set up solar-wind

Apollo 12 landed on the Moon on November 19, but Apollo 13, launched April 11, 1970, had to be aborted because of an explosion, and the astronauts, as recounted in a recent film through their great skill, resourcefulness, and courage, barely escaped death.

Apollo 14 (launched January 31, 1971), Apollo 15 (July 26, 1971), Apollo 16 (April 16, 1972), and Apollo 17 (December 7, 1972) all made successful lunar landings. Budgetary constraints, declining public interest, and the improving capabilities of unmanned missions eventually brought an end to the Apollo missions.

Lunar Probes

There were voices raised in protest, both in the political and scientific communities. Why try to put men on the moon, when unmanned probes could tell as much or more—and accomplish the mission with far less expense and danger?
The Russians had successfully launched the first lunar probe, Luna 2, on September 12, 1959, targeting and hitting the moon with it. Luna 3, launched the following month, on October 4, 1959, made the first circumnavigation of the moon
and transmitted back to Earth civilization’s first photographs of the Moon’s mysterious far side.
Another Soviet lunar first would come on January 31, 1966, when Luna 9 made a successful lunar soft landing—as opposed to a destructive impact.
In 1961, the United States launched the first of the Ranger series of nine unmanned lunar probes, hitting the moon with Ranger 4 in 1962 and orbiting it, with Rangers 7, 8, and 9, during 1964–1965. These last three missions generated some 17,000 high-resolution photographs of the lunar surface, not only valuable as astronomy, but indispensable as a prelanding survey.
From 1966 to 1968, seven Surveyor probes made lunar landings (not all successful), took photographs, sampled the lunar soil, and performed environmental analysis. Surveyor 6 (launched on November 7, 1967) landed on the lunar surface, took photographs, then lifted off, moved eight feet, landed again, and took more photographs. It was the first successful lift-off from an extraterrestrial body. The Lunar Orbiter series, five orbital missions launched during 1966–1967, mapped much of the lunar surface in 1,950 wide-angle and high-resolution photographs. These images were used to select the five primary landing sites for the manned Apollo missions.

JFK’s Challenge

On May 5, 1961, about three weeks after the Russians put a man into a single orbit, U.S. Navy commander Alan B. Shephard was launched on a 15-minute suborbital flight into space. Americans were proud of this achievement, to be sure, but the Soviets had clearly upstaged it. Just 20 days later, on May 25, President John F. Kennedy spoke to Congress: “I believe this nation should commit itself to achieving the goal, before the decade is out, of landing a man on the moon and returning him safely to Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space, and none will be so difficult or expensive to accomplish.”

First Observatories in Space

In 1962, the United States launched its first extraterrestrial observatory, the Orbiting Solar Observatory (OSO). It was the first of a series of solar observatories, designed to gather and transmit such data as the frequency and energy of solar electromagnetic radiation in ultraviolet, x-ray, and gamma ray regions of the spectrum—all regions to which our atmosphere is partially or totally opaque.

The Early Explorers

The first space satellite the United States sent into orbit was Explorer 1, launched on January 31, 1958. While the satellite didn’t beat Sputnik 1 into space, it accomplished considerably more than the Soviet probe. Explorer 1 carried equipment that discovered the innermost of the Van Allen radiation belts, two zones of charged particles that surround the earth. By 1975, when the Explorer series of missions ended, 55 satellites had been launched, including Explorer 38 (July 4, 1968), which detected galactic radio sources, and Explorer 53 (May 7, 1975), which investigated x-ray emission inside and beyond the Milky Way.

Satellites and Probes

Astronomers and other scientists were not always enthusiastically supportive of the manned space program, many of them feeling that it stole both public attention and government funding away from more useful data-gathering missions that could be carried out much more efficiently and inexpensively by unmanned satellites and probes. There is much truth to this sentiment. However, at least in the 1960s, unmanned exploratory missions continued to have high priority, and did not really suffer from the parallel development of the manned space program.

Early Human Missions

While both the Soviet Union and the United States launched a series of artificial satellites, the major goal quickly became “putting a man in space.” This objective was less scientific than psychological and political. The Soviet communists were determined to demonstrate the superiority of their technology generally and, in particular, the might of their ballistic missiles. At the time, their rockets were more powerful than what the United States had. The Soviets were eager to demonstrate that they were capable of lofting a person (and all of the machinery necessary to support a person) into space—or a warhead onto an American city.

Just as the Soviets had been first into orbit with Sputnik, so, on April 12, 1961, they were first to put a person, Yuri Alekseyevich Gagarin, into space—and into Earth orbit, no less. The first woman, Valentina Tereshkova of the USSR followed in 1963. It took America 20 more years to achieve this landmark. Through the rest of the 1960s, the Soviets and the Americans sent cosmonauts and astronauts into orbit and even had them practice working outside of their spacecraft in what were termed “extravehicular activities” or, more familiarly, space walks.

The Battle Cry of Sputnik

Impressive as the achievements of Piccard and others were, balloons could never move beyond the frontier of space. They needed the earth’s atmosphere to loft them.
After the war, scientists in America and the Soviet Union began experimenting with
so-called sounding rockets developed from the V-2s, in part to probe (sound) the upper atmosphere. While a sounding rocket was accelerated to speeds of up to 5,000 miles per hour, it would run out of fuel by about 20 miles up.

This acceleration gave the rockets sufficient velocity to continue their ascent to about a hundred miles, after which the rocket fell to Earth. Any instrumentation it carried had to be ejected, parachuted to safety and recovered, or the information had to be transmitted to a ground station by radio before the rocket crashed. The goal of rocket science at this point was not only to reach higher altitudes, but to achieve a velocity that could launch an artificial satellite into orbit around the earth. Imagine a rock thrown into the air. The force of gravity causes it to travel in a parabola and return to the earth. If the ball were thrown at a greater and greater velocity, it would travel farther and farther until it returned to the earth. At some velocity, however, the rock would never return to the earth, but continually fall toward it (this is what the moon is doing: orbiting the earth). It was no mean trick to get a satellite going fast enough to make it orbit the earth.

A single-stage rocket, like the V-2, exhausted its fuel supply before it reached sufficient altitude and velocity to achieve orbit. It lacked the necessary thrust. To build a more powerful rocket required a return to Goddard’s idea of a “stepped” or staged rocket. A staged rocket jettisoned large parts of itself as fuel in each lower part—or stage—ran out. Thus the rocket became progressively less massive as it ascended, both by burning fuel and by discarding the empty fuel tanks.

During the early and mid-1950s, there was much talk of putting a satellite into orbit, and both the United States and the Soviets declared their intention to do so. In the Cold War atmosphere of the time, it came as a great shock to Americans when the USSR was the first to succeed, launching Sputnik I (Russian for “satellite”) into orbit on October 4, 1957. The 185-pound (83.25 kg) satellite had been lofted to an altitude of about 125 miles (201 km) and had achieved the required Earth orbital velocity of some 18,000 miles (28,980 km) an hour. The first Sputnik was a primitive device by today’s standards. It did nothing more than emit a radio beep to tell the world it was there. But it didn’t have to do more than that. The point was made, the Space Age was born, and the space race had begun.

Playing with Balloons

While the V-2 had achieved great altitude by the 1940s, scientists were still a long way from attempting a human ascent. These early rockets were intended to explode at the end of the journey. If an instrument or a human were on board, explosions were to be avoided at all costs. In fact, another technology, the balloon, would be the first to take human beings into the upper stratosphere, the frontier of space. Auguste Piccard (1884–1962), a Swiss-born Belgian physicist, built a balloon in 1930 to study cosmic rays, which the earth’s atmosphere filters out. Piccard developed revolutionary pressurized cabin designs, which supported life at high altitudes, and, in 1932, reached an altitude of 55,563 feet. The following year, balloonists in the Soviet Union used Piccard’s design to reach 60,700 feet, and an American balloonist topped that later in the year at 61,221 feet.

From Scientific Tool to Weapon and Back Again

From the early 1900s through the 1930s, peacetime governments and the scientific community showed relatively little interest in supporting such pioneers as Tsiolkovsky, Goddard, and Oberth. Unfortunately, it took war in Europe, and a desire to launch bombs onto other nations, to spur serious, practical development of rockets. The research and development took place almost exclusively in Germany.
During the late 1930s, under the militaristic regime of Adolf Hitler, two rocket weapons were created. The first, known as the V-1, was more a pilotless jet aircraft than a rocket. About 25 feet long, it carried a 2,000-pound bomb at 360 miles per hour for a distance of about 150 miles. It was a fairly crude device: When it ran out of fuel, it crashed and exploded. Out of about 8,000 launched, some 2,400 rained down on London from June 13, 1944, to March 29, 1945, with deadly effect. In contrast to the V-1, the V-2 was a genuine rocket, powered not by an air-breathing jet engine, but by a rocket engine burning a mixture of alcohol and liquid oxygen.

The V-2 had a range of about 220 miles and also delivered 2,000 pounds of high explosives to its target. From September 8, 1944, to March 27, 1945, about 1,300 V-2s were launched against Britain. Scientists of every stripe spent the years from 1939 to 1945 directing their energies toward the defeat of the enemy. Many of the techniques developed during the war (radar technology and rocket engines, to name two) would become crucial to astronomy in the decades after WWII.
During the last days of the war in Europe, as U.S. forces invaded Germany from the west and Soviet forces invaded from the east, both sides scrambled to capture V-2s and, with them, German rocket scientists, such as Wernher von Braun. Both sides saw the potential in being able to deliver bombs over long distances. These rockets and the scientists who made them were at the center of the Cold War and the Space Race—a period of competition in politics and high technology between the two superpowers that dominated the postwar world.

This Really Is Rocket Science

While spaceflight was the subject of many centuries of speculation, three men worked independently to lay its practical foundation. Konstantin Eduardovich Tsiolkovsky (1857–1935) was a lonely Russian boy, almost totally deaf, who grew up in retreat with his books. He became a provincial schoolteacher, but his consuming interest was flight, and he built a wind tunnel to test various aircraft designs. Soon he became even more fascinated by the thought of space travel, producing the first serious theoretical books on the subject during the late nineteenth and early twentieth centuries.

Another quiet, introspective boy, this one a New Englander, Robert Hutchings Goddard (1882–1945), was captivated by H. G. Wells’s science-fiction novel War of the Worlds, which he read in an 1898 serialization in the Boston Post. On October 19, 1899 (as he remembered it for the rest of his life), young Goddard climbed a cherry tree in his backyard and “imagined how wonderful it would be to make some device which had even the possibility of ascending to Mars.” From that day, the path of his life became clear to him. Goddard earned his Ph.D. in physics in 1908 from Clark University in his hometown of Worcester, Massachusetts, and, working in a very modest laboratory, he showed experimentally that thrust and propulsion can take place in a vacuum (this follows from Newton’s Laws of motion—the expelled gases pushing forward on the rocket). He also began to work out the complex mathematics of energy production versus the weight of various fuels, including liquid oxygen and liquid hydrogen. These are the fuels that would ultimately power the great rockets that lofted human beings into orbit and to the moon—and still power the launch of many rockets today. Goddard was the first scientist to develop liquid-fuel rocket motors, launching the inaugural vehicle in 1926, not from some governmental, multimillion-dollar test site, but from his Aunt Effie’s farm in Auburn, Massachusetts. Through the 1930s and 1940s, he tested increasingly larger and more powerful rockets, patenting a steering apparatus and the idea of what he termed “step rockets”—what would later be called multistage rockets—to gain greater altitude.

Goddard’s achievements were little recognized in his own time, but, in fact, he had single-handedly mapped out the basics of space-vehicle technology, including fuel pumps, self-cooling rocket motors, and other devices required for an engine designed to carry human beings, telecommunications satellites, and telescopes into orbit. Hermann Oberth (1894–1989), born in Austria, was destined for a medical career, like his father, but his medical studies were interrupted by World War I. Wounded, he studied physics and aeronautics while recovering. While he was still in the Austrian army, he performed experiments to simulate weightlessness, and designed a longrange, liquid-propellant rocket. The design greatly impressed Oberth’s commanding officer, who sent it on to the War Ministry, which summarily rejected it. After the war, University of Heidelberg faculty members likewise rejected Oberth’s dissertation concerning rocket design. Undaunted, Oberth published it himself—to great acclaim—as The Rocket into Interplanetary Space (1923). In 1929, he wrote Ways to Spaceflight, winning a prize that helped him finance the creation of his first liquidpropellant rocket, which he launched in 1931.
During World War II, Oberth became a German citizen and worked with Wernher von Braun to develop rocket weapons.

The Space Race

While countless human beings have gazed up at the sky with wonder, a few were never content just to look. They didn’t want to wait for the information to get here, they wanted to go there. In the second century C.E., the Greek satirist Lucian wrote the first account we have of a fictional trip from the earth to the moon. Doubtless, someone had thought about such a trip before Lucian, and certainly many contemplated space travel after him. It was not until the eighteenth century that people were first lofted into the air by hot-air balloons. And while the airplane made its debut in 1903, human spaceflight—in which a human ventured beyond the earth’s protective atmospheric blanket—did not come about until the 1961 flight of a Soviet cosmonaut Yuri Alekseyevich Gagarin.