Frequently Asked Questions

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Space Shuttle and International Space Station
 
Q. How much does the Space Shuttle cost?
Q. What is a launch window?
Q. What are the names of the Space Shuttle orbiters?
Q. Is it true that launching the Space Shuttle creates a local ozone hole, and that the Space Shuttle releases more chlorine than all industrial uses worldwide?
Q. How are NASA program names such as Mercury, Gemini and Apollo chosen?
Q. Why hasn't the United States developed a way to rescue astronauts who are in trouble on space missions?
Q. What are the dimensions of the Space Shuttles?
Q. How much does it cost to launch a Space Shuttle?
Q. Did any Shuttle launches take place at Vandenberg Air Force Base in California?
Q. What types of propellants are used in the Shuttle? How much do they weigh?
Q. How fast does a Shuttle travel? What is its altitude? How much fuel does it use?
Q. Can the Space Shuttle fly to the Moon?
Q. Why is so much water released at the pad during launch?
Q. How many launches did Space Shuttle Columbia fly?
Q. How are modern spacesuits different than the first ones?
Q. What does STS stand for?
Q. How are Shuttle missions numbered? Why don't the missions launch in number order?
Q. How do they track time in space?
Q. How do astronauts in space go to the bathroom and take care of their personal hygiene?
Q. What should I do if I find a piece of debris that may have come from the Space Shuttle Columbia?
Q. Please explain the countdown sequence and all of the different holds.
Q. Where in the sky can I see the International Space Station or the Space Shuttle?
Q. What is the International Space Station used for?


Q. How much does the Space Shuttle cost?
A. The Space Shuttle Endeavour, the orbiter built to replace the Space Shuttle Challenger, cost approximately $1.7 billion.


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Q. What is a launch window?
A. A launch window is the precise period of time, ranging from minutes to hours, within which a launch must occur for a rocket or Space Shuttle to be positioned in the proper orbit.

Sometimes, this window is determined by the passing of an orbiting spacecraft with which the orbiter must rendezvous, such as the International Space Station or an ailing satellite. At other times, the Space Shuttle or an unmanned rocket must be launched within a certain window so that it can release its satellite payload at the right time to place it in an orbit over a certain region of Earth.

For more information, please click on the launch window link below.

+ Launch Window


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Q. What are the names of the Space Shuttle orbiters?
A. Their names, in the order they were built, are Enterprise, Columbia, Challenger, Discovery, Atlantis, and Endeavour. The Enterprise was flown only within Earth's atmosphere, during Shuttle approach and landing tests conducted in 1977. Columbia flew the first five Shuttle missions, beginning in April 1981, and was modified to fly extended-duration missions as long as 16 days. Columbia and its seven-member crew were lost during reentry on Feb. 1, 2003. Challenger was built as a vibration-test vehicle and then upgraded to become the second operational Shuttle. The Challenger and its seven-member crew were lost in a launch accident on Jan. 28, 1986. Discovery made its first flight in August 1984, and Atlantis followed in October 1985. Endeavour, built to replace Challenger, made its debut in May 1992 with a dramatic mission that featured the rescue of a stranded Intelsat 6 commercial communications satellite.

The link below will take you to the NASA Orbiter Fleet site providing descriptions of the Space Shuttles.

+ NASA's Orbiter Fleet


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Q. Is it true that launching the Space Shuttle creates a local ozone hole, and that the Space Shuttle releases more chlorine than all industrial uses worldwide?
A. No, that is not true. NASA has studied the effects of exhaust from the Space Shuttle's solid rocket motors on the ozone. In a 1990 report to Congress, NASA found that the chlorine released annually in the stratosphere (assuming launches of nine Shuttle missions and six Titan IVs -- which also have solid rocket motors -- per year) would be about 0.25 percent of the total amount of halocarbons released annually worldwide (0.725 kilotons by the Shuttle 300 kilotons from all sources).

The report concludes that Space Shuttle launches at the current rate pose no significant threat to the ozone layer and will have no lasting effect on the atmosphere. The exhaust plume from the Shuttle represents a trivial fraction of the atmosphere, and even if ozone destruction occurred within the initial plume, its global impact would be inconsequential.

Further, the corridor of exhaust gases spreads over a lateral extent of greater than 600 miles in a day, so no local "ozone hole" could occur above the launch site. Images taken by NASA's Total Ozone Mapping Spectrometer at various points following Shuttle launches show no measurable ozone decrease.


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Q. How are NASA program names such as Mercury, Gemini and Apollo chosen?
A. NASA officials consider a variety of factors when choosing a name for a program. Sometimes the names are descriptive, like Skylab or the Space Shuttle. Some names honor famous scientists and explorers, like Galileo, Hubble and Magellan.

Others are chosen from classical mythology that relates to some feature of the mission. Mercury was the messenger of the gods. Gemini, Latin for twins, was appropriate because each Gemini mission carried two astronauts. Apollo was the god of the Sun, who spread knowledge. For the origins of NASA names, please refer to the Web site link below.

+ Origin of NASA Names


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Q. Why hasn't the United States developed a way to rescue astronauts who are in trouble on space missions?
A. NASA has a range of systems that could come to the aid of endangered astronauts.

Following the Shuttle Challenger accident, NASA developed an emergency escape hatch for the Shuttle fleet that enables crewmembers to exit from the side of a Shuttle on a parachute during certain types of emergencies in the later parts of a landing.

Aboard the Space Station, resident crews have access to a modified Russian Soyuz spacecraft as an emergency rescue vehicle should they need to leave the outpost when a Space Shuttle is not docked to it. A more advanced rescue vehicle may be developed in the future.


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Q. What are the dimensions of the Space Shuttles?
A. For detailed information on the dimensions of the Space Shuttle, please click on the link below.

+ Shuttle Dimensions


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Q. How much does it cost to launch a Space Shuttle?
A. The average cost to launch a Space Shuttle is about $450 million per mission.


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Q. Did any Space Shuttle launches take place at Vandenberg Air Force Base in California?
A. A joint decision by the U.S. Air Force and NASA to consolidate Space Shuttle operations at Kennedy Space Center in Florida, following the Challenger accident in 1986, resulted in the official termination of the Space Shuttle program at Vandenberg on December 26, 1989, before any launches took place there. For more information about Vandenberg AFB, see the Web site link listed below.

+ Vandenberg AFB


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Q. What types of propellants are used in the Shuttle? How much do they weigh?
A. At liftoff, an orbiter and External Tank carry 835,958 gallons of the principle liquid propellants: hydrogen, oxygen, hydrazine, monomethylhydrazine, and nitrogen tetroxide. The total weight is 1,607,185 pounds.


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Q. How fast does a Shuttle travel? What is its altitude? How much fuel does it use?
A. Like any other object in low-Earth orbit, a Space Shuttle must reach speeds of about 17,500 miles per hour (28,000 kilometers per hour) to remain in orbit. The exact speed depends on the Space Shuttle's orbital altitude, which normally ranges from 190 miles to 330 miles (304 kilometers to 528 kilometers) above sea level, depending on its mission.

Each of the two Solid Rocket Boosters on the Space Shuttle carries more than one million pounds of solid propellant. The Space Shuttle's large External Tank is loaded with more than 500,000 gallons of super-cold liquid oxygen and liquid hydrogen, which are mixed and burned together to form the fuel for the orbiter's three main rocket engines.


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Q. Can the Space Shuttle fly to the Moon?
A. No, the Space Shuttle is designed to travel in low-Earth orbit (within a few hundred miles of the Earth's surface). It does not carry enough propellant to leave Earth's orbit and travel to the Moon. The Space Shuttle also is not designed to land on the Moon since it lands like an airplane and the Moon has no atmosphere. The Shuttle could be used to carry pieces of Moon or Mars vehicles to low-Earth orbit, where they could be assembled prior to beginning their mission.


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Q. Why is so much water released at the pad during launch?
A. A sound-suppression water system was installed on the pads at Launch Complex 39 following the Apollo Program to protect the Space Shuttle orbiter and its payloads from damage by acoustical energy reflected from the Mobile Launcher Platform (MLP) during launch. The Space Shuttle is much closer to the surface of the MLP than was the Saturn V rocket, carrying the Apollo spacecraft. Acoustical levels reach their peak when the Space Shuttle is about 300 feet above the platform and cease to be a problem at an altitude of about 1,000 feet. For additional information, please refer to the Web site link below.

+ Sound Suppression System


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Q. How many launches did Space Shuttle Columbia fly?
A. For a list of Columbia's launches prior to STS-107, please refer to the Web site link below.

+ Space Shuttle Launch History


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Q. How are modern spacesuits different than the first ones?
A. Early portable life-support systems were cumbersome and often very tiring to use. In the Mercury, Gemini and Apollo Programs, each spacesuit was tailored to fit a specific astronaut.

Today's Space Shuttle spacesuits come in two major pieces, each of which comes in several different sizes. They have more flexible joints than early spacesuits and better environmental controls. They also can be repaired and reused many times. Spacesuits on the International Space Station are improved versions of these suits.


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Q. What does STS stand for?
A. "STS" stands for "Space Transportation System," the original name for the Space Shuttle Program.


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Q. How are Space Shuttle missions numbered? Why don't the missions launch in number order?
A. Every launch is assigned an "STS" number. The mission numbers are assigned in order when they are on the "drawing board." However, some circumstances with payload development or orbiter processing, for example, may cause one mission to be postponed, allowing another mission to move ahead of it in line. Imagine that you are standing in line with other people to buy tickets to an event, and each one of you is given a number based on your place in the line. If you cannot find your money, you may say to the person behind you, "Go ahead of me because I'm not ready." Your number is the same and his number is the same; but he stepped ahead of you because you needed more time. Now, imagine that this process is happening to others in line. Everyone keeps his original number. Although the numbers may get mixed up, everyone eventually gets his or her turn.


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Q. How do they track time in space?
A. Astronauts go by Mission Elapsed Time, or MET. In this time frame, the clock starts ticking when the astronauts blast off. Minutes accumulate into days, hours, minutes and seconds that have passed since liftoff. The clock stops when the Space Shuttle's wheels again touch Earth, and the total MET is tabulated.


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Q. How do astronauts in space go to the bathroom and take care of their personal hygiene?
A. Astronauts brush their teeth just like they do on Earth. There is no shower on the orbiter, so astronauts must make do with sponge baths until they return home. Each Space Shuttle has a toilet that can be used by both men and women. Designed to be as much as possible like those on Earth, the units use flowing air instead of water to move waste through the system. Solid wastes are compressed and stored onboard, and then removed after landing. Wastewater is vented to space, although future systems may recycle it, such as they do on the International Space Station. The air is filtered to remove odor and bacteria and then returned to the cabin.


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Q. What should I do if I find a piece of debris that may have come from the Space Shuttle Columbia?
A. If you find a piece of debris that may have come from the Space Shuttle Columbia, you should not touch it but call the Columbia Recovery Office at (866) 446-6603 (toll-free). All debris is United States Government property and should be reported to government authorities. Unauthorized persons found in possession of accident debris will be prosecuted to the full extent of the law.


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Q. Please explain the countdown sequence and all of the different holds.
A. The basics of the countdown and the scheduled holds are available online at the Web site link below.

+ Countdown Sequence


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Q. Where in the sky can I see the International Space Station or the Space Shuttle?
A. The naked-eye visibility charts for the International Space Station and the Space Shuttle during a mission can be found through the Human Space Flight home page at the Web site link listed below.

+ ISS Sightings


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Q. What is the International Space Station used for?
A. The International Space Station (ISS), the largest international scientific and technological endeavor ever undertaken, draws on the resources and scientific expertise of 16 nations around the world. Canada, Japan, 11 members of the European Space Agency, Russia and Brazil are our partners. It is a permanent laboratory where gravity, temperature and pressure can be manipulated in a variety of scientific and engineering pursuits in ways that are impossible in ground-based laboratories.

The ISS tests new, advanced industrial materials and communications technology, and conducts medical research. For more information, please click on the links below.

+ ISS Partners
+ ISS Overview


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