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Image Below form NASA: Tiny Craters on Meridiani Planum These two craters, each smaller than a foot in diameter and less than one-half inch deep, were found intact by NASA's Mars rover Opportunity. Image credit: NASA/JPL

With the major Apollo development effort winding down in the second half of the 1960s, NASA started looking to the future of the space program. They envisioned an ambitious program consisting of a large space station being launched on huge boosters, served by a reusable logistics "space shuttle", both providing services for a permanantly manned Lunar colony and eventual manned missions to Mars.

International Space Station
International Space Station Continuing on from the United States' Skylab and Russia's Mir, the International Space Station (ISS) represents a permanent human presence in space. The space station is located in orbit around the Earth at an altitude of approximately 386 km, a type of orbit usually termed low Earth orbit. (The actual height varies over time by several kilometres due to atmospheric drag and reboosts.) It orbits Earth at a period of about 92 minutes; on December 1, 2003 it had completed over 28,700 orbits since launch. It is serviced primarily by the Space Shuttle, and Soyuz and Progress spacecraft units. It is still being built, but is home to some experimentation already. At present, the station has a capacity for a crew of three, who America's first space station, the 75 ton Skylab was launched May 14, 1973 by a two-stage version of the Saturn V booster (the SL-1 mission). Severe damage was sustained during launch, including the loss of the station's micrometeoroid shield/sun shade and one of its main solar panels. Debris from the lost micrometeroid shield further complicated matters by pinning the remaining solar panel to the side of the station, preventing its deployment and thus leaving the station with a huge power deficit. The station underwent a extensive repair by the first crew launched on May 25, 1973 (the SL-2 mission) atop a Saturn 1B. Two additional missions followed on July 28, 1973 (SL-3) and November 16, 1973 (SL-4) with stay times of 28, 59, and 84 days, respectively. The last Skylab crew returned to Earth on February 8, 1974.

Skylab was actually the refitted S-IVB third stage of a Saturn V booster, a leftover from the Apollo program originally intended for one of the canceled moon landing missions (Apollos 18-20). A product of the Apollo Applications program (a program tasked with finding long-term uses for Apollo program hardware), Skylab was originally planned as a minimially-altered S-IVB to be launched on a Saturn IB rocket. The small size of the IB would have required Skylab to double as a rocket stage during launch, only being retrofitted as a space station once on-orbit. With the cancellation of Apollo missions 18-20 a Saturn V was made available and thus the "Wet Workshop" concept, as it was called, was put aside and Skylab was launched dry and fully outfitted. Skylab's grid flooring system is a highly visable legacy of the wet workshop concept.

Following the last mission the Station was positioned in a parking orbit expected to last at least 8 years. Increased solar activity heating the outer layers of the earth's atmosphere and thereby increasing drag on the Station led to an early reentry on July 11, 1979. Skylab disintegrated over Western Australia and the Indian Ocean, casting large pieces of debris in populated areas (without injury). The reentry prevented any further use by the then unfinished Space Shuttle as was envisioned by some at NASA.

Two flight-quality Skylabs were built, the second, a backup, is on display at the National Air and Space Museum in Washington, DC.

The last remaining debate was over the nature of the boosters. NASA had been looking at no less than four solutions to this problem, one a development of the existing Saturn lower stage, another using "dumb" pressure-fed liquid fuel engines of a new design, and finally either a large single solid rocket, or two (or more) smaller ones. The decision was eventually made on the smaller solids due to their lower development costs (a decision that had been echoed throughout the whole Shuttle program). While the liquid fueled systems provided better performace and enhanced safety, delivery capability to orbit is much more a function of the upper-stage performance and weight than the lower. The money was simply better spent elsewhere.

The Air Force relucantly agreed, but only after demanding a large increase in capability to allow for launching their projected spy satellites (mirrors are heavy). These were quite large, weighing an estimated 40,000 lbs, and needed to be put into polar orbit, which requires more energy to get to than the more common LEO. And since the AF also wanted to be able to abort after a single orbit (as did NASA), and land at the launch site (unlike NASA), the spacecraft would also require the ability to manuver significantly to either side of its orbital track to adjust for the launching point rotating away from it while in polar orbit - in a 90 minute orbit Vandenberg would move over 1,000 miles, whereas in a "normal" equatorial orbit NASA needed the range would be less than 400. This large 'cross-range' capability meant the craft had to have a greater lift to drag ratio than originally planned. This required the addition of bigger, heavier wings.

The Shuttle in retrospect

Whilst the shuttle has been a reasonably successful launch vehicle, it had been unable to meet its goals of radically reducing flight launch costs, as each flight costs on the order of $500 million rather than initial projections of $10 to $20 million.

Although the design is radically different than the original concept, the project was still supposed to meet the upgraded AF goals as well as be much cheaper to fly in general. What went wrong?

One issue appears to be inflation. During the 1970s the US suffered from the worst inflation in modern history, driving up costs about 200% by 1980. In contrast, the rate between 1990 and 2000 was only 34% in total. This has the effect of magnifying the development costs of the shuttle tremendously.

However this doesn't explain the high costs of the continued operations of the shuttle. Even accounting for inflation the launch costs on the original estimates should be about $100 million today. To explain this you have to look at the operational details of maintaining and servicing the shuttle fleet, which have turned out to be tremendously more expensive than anticipated.

When originally conceived the shuttle was to operate similar to an airliner. After landing the Orbiter would be checked out and start "mating" to the rest of the system (the ET and SRBs) and be ready for launch in as little as two weeks. Instead this turnaround process in fact takes months. This is due, in turn, to the continued "upgrading" of the inspection process as a result of hardware decisions made to reduce short-term development costs which resulted in higher maintenance requirements which where exacerbated by the fallout from the loss of Challenger. Even simple tasks now require unbelievable amounts of paperwork. This paperwork results from the fact that, unlike current expendable launch vehicles, the Space Shuttle is manned and has no escape systems to speak of and therefore any accident which would result in the loss of booster would also result in the loss of the crew which is, of course, unacceptable. Because loss of crew is unacceptable, the primary focus of the shuttle program is to return the crew to earth safely, which can conflict with other goals, namely to launch satellites cheaply. Furthermore, because there are cases where there are no abort modes, no potential way to prevent failure from becoming critical, many pieces of hardware simply must function perfectly and so must be carefully inspected before each flight.

The result is a massively inflated manpower bill. There are 25,000 workers in shuttle operations (perhaps an older number), so simply multiply any figure that you choose for an average annual salary, divide by six (or 4 or 7...launches per year), and there you have it.

The lessons of the shuttle have been seen as different depending on who you ask. In general, however, future designers look to systems with only one stage, automated checkout, and in some cases, overdesigned (more durable) low-tech systems.

Perhaps the most annoying aspect of the shuttle system is to consider the Air Force participation. While the blame rests solely at the feet of NASA for getting them involved in the first place, it was the Air Force requirements that drove the system to be as complex and expensive as it is today. Ironically neither NASA nor the Air Force got the system they wanted or needed, and the Air Force eventually threw in the towel and returned to their older launch systems and abandoned their Vandenburg shuttle launch plans. The capabilities which most seriously hobbled the Shuttle system, namely the 65,000 payload, large payload bay, and 1000 mile cross-range, have in fact, except for the payload bay, never been used.

Shuttles
4 The Shuttle decision
5 Shuttle development
6 The Shuttle in retrospect
7 Shuttle description
8 Shuttle accidents
9 Previous Programs
10 External links

Components

The Space Shuttle consists of four main components:

Hubble Space Telescope
Hubble Space Telescope The Hubble Space Telescope (HST, or Hubble) is a telescope located at the outer edges of Earth's atmosphere, about 600 kilometerss above the ground, orbiting the Earth every 100 minutes. It was placed into orbit, in April 1990, as a joint project of NASA and the ESA. The telescope can achieve optical resolutions greater than 0.1 arcseconds. The HST is named after Edwin Hubble. It is scheduled for replacement, by the James Webb Space Telescope (JWST), in 2009. Every day, the Hubble Space Telescope archives 3 to 5 gigabytes of data and delivers between 10 and 15 gigabytes to astronomers. Working outside the atmosphere has advantages because the atmosphere obscures images and filters out electromagnetic radiation at certain wavelengths, mainly in the infrared. Hubble

Space Camp
Space Camp Space Camp is a 1986 movie which was based on a book written by Patrick Bailey and Larry B Williams and a screenplay by WW Wicket and Casey T Mitchell. In the movie, four teenagers and a twelve year old boy go to a NASA space camp, to spend three weeks of their summer training as astronauts and learning about the space program in general. There, they will meet a female instructor who is frustrated at the fact she still hasn't gotten a chance to be up there, despite this being her life's dream. But things start to unravel when the 12 year old boy, Max, saves the life of a robot named Jinx, and, to return the favor, Jinx decides to send Max

HAL/S
computer language, best known for its use in the Space Shuttle. It was written by Intermetrics in the 1970s for NASA. HAL/S is written in a dialect of PL/I known as XPL The three key factors in writing the language were reliability, efficiency, and machine-independence. The language is designed to allow tasks such as performing aerospace related vector/matrix arithmetic to be accomplished in a way that is easily understandable to people who have studied the subject. HAL/S is written without functions (such as GOTO in BASIC) that are known to be the cause of many errors. There are no abreviations for keywords, and keywords are all reserved so that they cannot also be used as variables. Considerations such as this are designed to reduce the chances of errors occurring, and also

Barbara Morgan
R. Morgan (November 28, 1951 - ) is the first NASA Educator Astronaut, scheduled to fly on STS-118. Morgan trained to fly on the ill-fated STS-51-L mission of Space Shuttle Challenger as backup to Christa McAuliffe and has remained involved in the space program since then. Personal Data Born November 28, 1951, in Fresno, California. Married to Clay Morgan of McCall, Idaho. They have two sons. She is a classical flutist who also enjoys jazz, literature, hiking, swimming, cross-country skiing, and her family. Her parents are Dr. and Mrs. Jerry Radding. Her mother-in-law is Mrs. Clay Morgan. Education Hoover High School, Fresno, California, 1969; B.A., Human Biology, with distinction, Stanford University, 1973; Teaching Credential, College of Notre Dame, Belmont, California, 1974. Teaching Experience Morgan began her teaching career in 1974 on