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Space shuttle is a reusable spacecraft.
Space shuttle is officially called Space Transportation System or STS. The space shuttle is the United States government's current manned launch vehicle. There were a total of five space shuttle usable orbiters built, of which three remain active. The winged space shuttle orbiter is launched vertically, usually carrying five to seven Astronauts (although eight have been carried and eleven could be accommodated in emergency) and up to 50,000 lb (22,700 kg) of payload into Low Earth orbit. When the space shuttle mission is complete, the space shuttle fires its maneuvering thrusters to drop out of orbit and re-enters the Earth's atmosphere. During the descent and landing, the space shuttle orbiter acts as a glider and makes a completely unpowered landing. The space shuttle is considered one of the most complex machines made by humans.
The space shuttle is the first orbital spacecraft designed for partial reusability. The space shuttle is also so far the only winged manned spacecraft to achieve orbit and land. It carries large payloads to various orbits, provides crew rotation for the International Space Station (ISS), and performs servicing missions. The orbiter can also recover satellites and other payloads from orbit and return them to Earth, but this capacity has not been used often. However, it has been used to return large payloads from the ISS to Earth, as the Russian Soyuz spacecraft has limited capacity for return payloads. Each space shuttle was designed for a projected lifespan of 100 launches or 10 years' operational life.
Four space shuttles were initially constructed: Columbia, Challenger, Discovery and Atlantis. Challenger was destroyed on launch in 1986, and Endeavour constructed as a replacement. Columbia was destroyed on re-entry in 2003.
NASA announced in 2004 that the Space Shuttle will be retired in 2010 and replaced by the Orion, a new vehicle that is designed to take humans to the Moon and beyond.
Description of the space shuttle.
Shuttles are each a partially reusable launch system composed of three main assemblies: the reusable Orbiter Vehicle (OV), the expendable external tank (ET), and the two reusable Solid Rocket Boosters (SRBs). The tank and boosters are jettisoned during ascent; only the orbiter goes into orbit. The vehicle is launched vertically like a conventional rocket, and the orbiter glides to a horizontal landing, after which it is refurbished for reuse.
Orbiter Vehicle of the space shuttle: Space Shuttle Orbiter.
The Orbiter resembles an aircraft with double-delta wings, swept 81º at the inner leading edge and 45º at the outer leading edge. Its vertical stabilizer's leading edge is swept back at a 45º angle. The four elevons, mounted at the trailing edge of the wings, and the rudder/speed brake, attached at the trailing edge of the stabilizer, with the body flap, control the Orbiter during descent and landing. The Orbiter has a large 60 by 15 ft (18 m by 4.6 m) payload bay, filling most of the fuselage. Three Space Shuttle Main Engines (SSMEs) are mounted on the Orbiter's aft fuselage in a triangular pattern. The three engines can swivel 10.5 degrees up and down and 8.5 degrees from side to side during ascent to change the direction of their thrust and steer the Shuttle as well as push. The orbiter structure is made primarily from aluminium alloy, although the engine thrust structure is made from titanium (alloy).
External Tank of the space shuttle.
The External Tank (ET) provides approximately 535,000 gallons (2.025 million liters) of Liquid hydrogen and Liquid oxygen propellant to the SSMEs. It is discarded 8.5 minutes after launch at an altitude of 60 nautical miles (111 km), which then burns up on re-entry. The ET is constructed mostly of inch thick aluminium-lithium alloy.
The external tanks of the first two missions were painted white, which added an extra 600 pounds (273 kg) of weight to each ET. Subsequent missions have had unpainted tanks showing the natural orange-brown color of the spray-on foam insulation. The lighter, unpainted tanks have increased the Payload capacity by almost the entire weight savings of 600 pounds.
Solid Rocket Boosters of the space shuttle.
Two Solid Rocket Boosters (SRBs) provide about 83% of the vehicle's thrust at liftoff and during the first stage ascent. They are jettisoned two minutes after launch at a height of about 150,000 feet (45.7 km), then deploy parachutes and land in the ocean to be recovered. The SRB cases are made of steel about ½ inch (1.27 cm) thick.
Flight systems on the space shuttle.
Early Shuttle missions took along the GRiD Compass, arguably one of the first laptop computers. The Compass sold poorly, because it cost at least $8000, but offered unmatched performance for its weight and size. NASA was one of its main customers.
The shuttle was one of the earliest craft to use a computerized fly-by-wire digital flight control system. This means no mechanical or hydraulic linkages connect the pilot's control stick to the control surfaces or reaction control system thrusters.
A primary concern with digital fly-by-wire systems is reliability. Much research went into the shuttle computer system. The shuttle uses five identical redundant IBM 32-bit general purpose computers (GPCs), model AP-101, constituting a type of embedded system. Four computers run specialized software called the Primary Avionics Software System (PASS). A fifth backup computer runs separate software called the Backup Flight System (BFS). Collectively they are called the shuttle Data Processing System (DPS).
The design goal of the shuttle DPS is fail operational/fail safe reliability. After a single failure the shuttle can continue the mission. After two failures it can land safely.
The four general-purpose computers operate essentially in lockstep, checking each other. If one computer fails, the three functioning computers "vote" it out of the system. This isolates it from vehicle control. If a second computer of the three remaining fails, the two functioning computers vote it out. In the rare case of two out of four computers simultaneously failing (a two-two split), one group is picked at random.
The Backup Flight System (BFS) is separately developed software running on the fifth computer, used only if the entire four-computer primary system fails. The BFS was created because although the four primary computers are hardware redundant, they all run the same software, so a generic software problem could crash all of them. This is unlikely to ever happen, as embedded system avionic software is developed under totally different conditions from commercial software. For example, the number of code lines is tiny compared to a commercial operating system, changes are only made infrequently and with extensive testing, and many programming and test personnel work on the small amount of computer code. However in theory it can fail, and the BFS exists for that contingency.
The software for the shuttle computers is written in a high-level language called HAL/S, somewhat similar to PL/I. It is specifically designed for a real time embedded system environment.
The IBM AP-101 computers originally had about 424 kilobytes of magnetic core memory each. The CPU could process about 400,000 instructions per second. They have no hard disk drive, but load software from tape cartridges.
In 1990 the original computers were replaced with an upgraded model AP-101S, which has about 2.5 times the memory capacity (about 1 megabyte) and three times the processor speed (about 1.2 million instructions per second). The memory was changed from magnetic core to semiconductor with battery backup.
Upgrades to the space shuttle.
Internally the Shuttle remains largely similar to the original design, with the exception of the improved avionics computers. In addition to the computer upgrades, the original vector graphics monochrome cockpit displays were replaced with modern full-color, flat-panel display screens, similar to contemporary airliners like the Airbus A320. This is called a "glass cockpit". In the Apollo-Soyuz Test Project tradition, programmable calculators are carried as well (originally the HP-41C). With the coming of the ISS, the Orbiter's internal airlocks have been replaced with external docking systems to allow for a greater amount of cargo to be stored on the Shuttle's mid-deck during Station resupply missions.
The Space Shuttle Main Engines have had several improvements to enhance reliability and power. This explains phrases such as "Main engines throttling up to 104%." This does not mean the engines are being run over a safe limit. The 100% figure is the original specified power level. During the lengthy development program, Rocketdyne determined the engine was capable of safe reliable operation at 104% of the originally specified thrust. They could have rescaled the output number, saying in essence 104% is now 100%. However this would have required revising much previous documentation and software, so the 104% number was retained. SSME upgrades are denoted as "block numbers", such as block I, block II, and block IIA. The upgrades have improved engine reliability, maintainability and performance. The 109% thrust level was finally reached in flight hardware with the Block II engines in 2001. The normal maximum throttle is 104%, with 106% and 109% available for abort emergencies.
For the first two missions, STS-1 and STS-2, the external tank was painted white to protect the insulation that covers much of the tank, but improvements and testing showed that it was not required. The weight saved by not painting the tank results in an increase in payload capability to orbit. Additional weight was saved by removing some of the internal "stringers" in the hydrogen tank that proved unnecessary. The resulting "light-weight external tank" has been used on the vast majority of Shuttle missions. STS-91 saw the first flight of the "super light-weight external tank". This version of the tank is made of the 2195 aluminium-lithium alloy. It weighs 7,500 lb (3.4 t) less than the last run of lightweight tanks. As the Shuttle cannot fly unmanned, each of these improvements has been "tested" on operational flights.
The SRBs (Solid Rocket Boosters) have undergone improvements as well. Notable is the adding of a third O-ring seal to the joints between the segments, which occurred after the Challenger disaster.
Several other SRB improvements were planned in order to improve performance and safety, but never came to be. These culminated in the considerably simpler, lower cost, probably safer and better performing Advanced Solid Rocket Booster which was to have entered production in the early to mid-1990s to support the Space Station, but was later cancelled to save money after the expenditure of $2.2 billion. The loss of the ASRB program forced the development of the Super LightWeight external Tank (SLWT), which provides some of the increased payload capability, while not providing any of the safety improvements. In addition the Air Force developed their own much lighter single-piece SRB design using a filament-wound system, but this too was cancelled.
STS-70 was delayed in 1995 when woodpeckers bored holes in the foam insulation of Discovery's external tank. Since then, NASA has installed commercial plastic owl decoys and inflatable owl balloons which must be removed prior to launch.
A cargo-only, unmanned variant of the Shuttle has been variously proposed and rejected since the 1980s. It is called the Shuttle-C and would trade re-usability for cargo capability with large potential savings from reusing technology developed for the Space Shuttle.
On the first four Shuttle missions, astronauts wore full-pressure Launch Entry Suit (LES) including a helmet during ascent and descent. From the fifth flight, STS-5, until the loss of Challenger only helmets were worn without a suit. The LES with a helmet was reinstated when Shuttle flights resumed in 1988. The LES ended its service life in late 1995, replaced by the Advanced Crew Escape Suit (ACES).
Technical data about the space shuttle: Orbiter Specifications (for Endeavour, OV-105).
External tank specifications space shuttle.
Solid Rocket Booster Specifications
System Stack Specifications
Launch of the space shuttle.
The shuttle will not be launched under conditions where it could be struck by lightning. Aircraft are often struck by lightning with no adverse effects because the electricity of the strike is dissipated through its conductive structure and the aircraft is not electrically grounded. Like most jet airliners, the shuttle is mainly constructed of conductive aluminium, which would normally protect the internal systems. However, upon takeoff the shuttle sends out a long exhaust plume as it ascends, and this plume can trigger lightning by providing a current path to ground. While the shuttle might safely endure a lightning strike, a similar strike caused problems on Apollo 12, so for safety NASA chooses not to launch the shuttle if lightning is possible.
At T minus 16 seconds, the massive sound suppression system (SPS) begins to drench the Mobile Launcher Platform (MLP) and SRB trenches with 300,000 U.S. gallons (1,135,623 L) of water to protect the Orbiter from damage by acoustical energy and rocket exhaust reflected from the flame trench and MLP during liftoff.
At T-minus 10 seconds, hydrogen igniters are activated beneath each engine bell to quell the stagnant gas inside the cones before ignition. Failure to burn these gases can trip the onboard sensors and create the possibility of an overpressure and explosion of the vehicle during the firing phase.
The three Space Shuttle Main Engines (SSMEs) start at T minus 6.6 seconds. The main engines ignite sequentially via the shuttle's general purpose computers (GPC's) at 0.25 second intervals. The GPC's require that the engines reach 90% of their rated performance to complete the final gimbal of the main engine nozzels to liftoff configuration. All three SSMEs must reach the required 100% thrust within three seconds to initiate the SRB firing command. If the onboard computers verify normal thrust buildup, at T minus 0 seconds, the SRBs are ignited. At this point the vehicle is committed to takeoff, as the SRBs cannot be turned off once ignited. After the SRBs reach a stable thrust ratio, pyrotechnic bolts are detonated by radio controlled signals from the shuttle's GPC's to release the vehicle. The GPC's mandate ignition sequences via the "Master Events Controller," a computer program integrated with the shuttle's four redundant computer systems. There are extensive emergency procedures (abort modes) to handle various failure scenarios during ascent. Many of these concern SSME failures, since that is the most complex and highly stressed component. After the Challenger disaster, there were extensive upgrades to the abort modes.
When watching a launch, look for the "nod" ("twang" in NASA lingo). After the main engines start, but while the solid rocket boosters are still clamped to the pad, the offset thrust from the Shuttle's three main engines causes the entire launch stack (boosters, tank and shuttle) to flex forwards about 2m at cockpit level. As the boosters flex back into their original shape, the launch stack springs slowly back upright. This takes approximately 6 seconds. At the point when it is perfectly vertical, the boosters ignite and the launch commences.
Shortly after clearing the tower the Shuttle begins a roll and pitch program so that the vehicle is below the external tank and SRBs. The vehicle climbs in a progressively flattening arc, accelerating as the weight of the SRBs and main tank decrease. To achieve low orbit requires much more horizontal than vertical acceleration. This is not visually obvious since the vehicle rises vertically and is out of sight for most of the horizontal acceleration. The near circular Orbital velocity at the 380 km (236 miles) altitude of the International Space Station is 7.68 km per second (27,648 km/h, 17,180 mph), roughly equivalent to Mach 23. For missions towards the International Space Station, the shuttle must reach an azimuth of 51.6 degrees inclination to rendezvous with the station.
Around a point called "Max Q", where the aerodynamic forces are at their maximum, the main engines are temporarily throttled back to avoid overspeeding and hence overstressing the Shuttle, particularly in vulnerable areas such as the wings. At this point, a phenomenon known as the "Prandtl-Glauert Singularity" occurs, where condensation clouds form during the vehicle's transition to supersonic speed.
126 seconds after launch, explosive bolts release the SRBs and small separation rockets push them laterally away from the vehicle. The SRBs parachute back to the ocean to be reused. The Shuttle then begins accelerating to orbit on the Space Shuttle Main Engines. The vehicle at that point in the flight has a thrust to weight ratio of less than one - the main engines actually have insufficient thrust to exceed the force of gravity, and the vertical speed given to it by the SRBs temporarily decreases. However, as the burn continues, the weight of the propellant reduces and the ever-lighter vehicle produces more and more acceleration until the thrust-to-weight ratio exceeds 1 again and the vehicle can hold itself up.
The vehicle continues to climb and takes on a somewhat nose-up angle to the horizon - it uses the main engines to gain and then maintains altitude whilst it accelerates horizontally towards orbit. At about five and three-quarter minutes into ascent, the orbiter rolls heads up to switch communication links from ground stations to Tracking and Data Relay Satellites.
Finally, in the last tens of seconds of the main engine burn, the mass of the vehicle is low enough that the engines must be throttled back to limit vehicle acceleration to 3 g, largely for astronaut comfort.
Before complete depletion of propellant, as running dry would destroy the engines, the main engines are shut down. The oxygen supply is terminated before the hydrogen supply, as the SSMEs react unfavorably to other shutdown modes. The external tank is released by firing explosive bolts and falls, largely burning up in the atmosphere, though some fragments fall into the Indian Ocean.
To prevent the shuttle from following the external tank back into the atmosphere, the OMS engines are fired to raise the perigee out of the atmosphere. On some missions (e.g., STS-107 and missions to the ISS), the OMS engines are also used while the main engines are still firing.
Landing of the space shuttle.
The vehicle begins reentry by firing the OMS engines in the opposite direction to orbital motion for about three minutes. The resulting deceleration of the Shuttle lowers its orbit perigee down into the atmosphere. This OMS firing is done roughly halfway around the globe from the landing site. The entire reentry, except for lowering the landing gear and deploying the air data probes, is then under computer control. However the reentry can be and has (once) been flown manually. The final landing can be done on autopilot, but is usually hand flown.
The vehicle starts significantly entering the atmosphere at about 400,000 ft (120 km) at around Mach 25 (8.2 km/s). The vehicle is controlled by a combination of RCS thrusters and control surfaces, to fly at a 40 degrees nose-up attitude producing high drag, not only to slow it down to landing speed, but also to reduce reentry heating. In addition, the vehicle needs to bleed off extra speed before reaching the landing site. This is achieved by performing s-curves at up to a 70 degree roll angle.
In the lower atmosphere the Orbiter flies much like a conventional glider, except for a much higher descent rate, over 10,000 feet (3 km) per minute. It glides with a ratio of 4:1. At approximately Mach 3, two air data probes, located on the left and right sides of the Orbiter's forward lower fuselage, are deployed to sense air pressure related to vehicle's movement in the atmosphere.
When the approach and landing phase begins, the Orbiter is at 10,000 ft (3048 m) altitude, 7.5 miles (12.1 km) to the runway. The pilots apply aerodynamic braking to help slow down the vehicle. The Orbiter's speed is reduced from 424 mph (682 km/h) to approximately 215 mph (346 km/h), (compared to 160 mph for a jet airliner), at touch-down. The landing gear is deployed while the Orbiter is flying at 267 mph (430 km/h). To assist the speed brakes, a 40 ft (12.2 m) drag chute is deployed once the nose gear touches down at about 213 mph (343 km/h). It is jettisoned as the Orbiter slows through 69 mph (111 km/h).
After landing, the vehicle stands on the runway for several minutes to permit the fumes from poisonous Hydrazine, used as propellant for attitude control, to dissipate, and for the shuttle fuselage to cool before the astronauts disembark.
Conditions permitting, the Space Shuttle will always land at Kennedy Space Center. However, if the conditions make landing there unfavorable, the Shuttle can touch down at Edwards Airforce Base in California or at other sites. A landing at Edwards means that the shuttle must be mated to the Shuttle Carrier Aircraft and returned to Cape Canaveral, costing NASA roughly an additional million dollars.
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Fiction and games about the space shuttle.
More About The Space Shuttle.
Aug 19, 2005 - Even after all their safety improvements, NASA engineers weren't able to completely solve the problem of foam shedding off the space shuttle's external fuel tank. During Discovery's launch a large piece flew off; fortunately it completely missed the orbiter, but the risk remains. In order to give engineers time to come up with a solution, NASA is targeting March 2006 for Discovery to return to the launch pad and continue construction of the International Space Station.
Aug 10, 2005 - With Discovery's return to flight complete, NASA is counting up the accomplishments for this shuttle mission: 14 days in space, three spacewalks, all four space station gyros returned to service, high resolution images of launch and in-orbit, and the first spacewalk to the underside of the shuttle. Discovery will now be ferried back to NASA's Kennedy Space Center in Florida atop a modified Boeing 747 aircraft.
Aug 9, 2005 - The space shuttle Discovery returned safely back to Earth this morning, landing at Edwards Air Force Base at 1211 UTC (8:11 am EDT). Poor weather over Florida's Cape Canaveral prevented two landing attempts, so managers decided to switch the landing location to California. This safe landing brought mission STS-114 to a successful conclusion, two and half years after the catastrophic destruction of Columbia. The next shuttle, Atlantis, is scheduled to launch September 22, but it all depends on whether they can resolve the foam shedding problems with Discovery's launch.
Aug 8, 2005 - The space shuttle Discovery's landing has been pushed back to Tuesday because of low clouds above Florida's Cape Canaveral on Monday. All three primary landing sites will be activated on Tuesday, so the shuttle can potentially land at Cape Canaveral, Edwards Air Force Base in California, or White Sands Space Harbor in New Mexico. Weather forecasters are expecting similar weather in Florida for Tuesday, so it's likely Discovery will have to use an alternative site. The first landing attempt will be at 0907 UTC (5:07 am EDT).
Aug 5, 2005 - Skywatchers in the Southeastern United States will have an opportunity to watch the International Space Station and the space shuttle Discovery fly overhead on Saturday morning at 5:50 am CDT.. Discovery will have undocked from the station three hours previously, so the two objects will be separated visually by about the width of the Moon. As a special bonus, the two spacecraft will pass close to the planet Mars as well.
Aug 5, 2005 - NASA astronauts on board Discovery and the International Space Station held a tribute to remember the crew of Columbia, which was destroyed during its re-entry more than two years ago. Each crewmember wore a red shirt with Columbia's STS-107 mission patch, and spoke, paying their respects to the crew of STS-107, as well as Challenger, Apollo 1, Soyuz 1 and 11.
Aug 5, 2005 - NASA has given the space shuttle Discovery a green light to return to Earth on Monday, August 8th. The agency's Mission Management Team has decided that the shuttle's heat shield and other systems are in good shape, after Wednesday's spacewalk to remove excess gap filler between shuttle tiles. The team also decided that a torn thermal blanket won't be a risk as the shuttle re-enters the atmosphere.
Aug 4, 2005 - Astronaut Steve Robinson successfully pulled out the protruding gap fillers from between the shuttle's thermal protection tiles during his 7 hour spacewalk yesterday. The gap fillers came out with a simple tug; Robinson didn't need the makeshift hacksaw he'd brought with him. NASA officials were worried that the Nextel fabric could lead to overheating in the area during Discovery's re-entry. The filler material keeps the shuttle's heat tiles from bumping into each other during launch, but aren't necessary during landing.
Aug 3, 2005 - Astronauts Steve Robinson and Soichi Noguchi made their preparations to head outside the space shuttle Discovery today. This spacewalk had been planned for the mission, but shuttle managers gave the two men the additional task of fixing two protruding gap fillers in between the heat tiles on the underside of the shuttle. Robinson will attempt to pull the excess material out by hand, or use a hacksaw if that doesn't work.
Aug 3, 2005 - Shuttle managers decided on Wednesday that Discovery's leading wing edge is safe for it to make re-entry. This is the area that was damaged by falling foam during Columbia's launch, and caused the catastrophe during re-entry. High resolution photographs have analyzed every part of Discovery, and the only concerning area were some protruding tile gap fillers, which will be fixed during a spacewalk on Wednesday.
Flying Foam Grounds Shuttle Fleet
Jul 28, 2005 - Although Discovery made it safely into orbit, potentially catastrophic chunks of foam dislodged from its fuel tank on Tuesday's launch. After reviewing launch video and photographs, managers identified a few places where pieces of foam flew off the tank, including one piece as large as 90-cm (35 inches) across. Fortunately it completely missed the shuttle, but if it had hit, the damage would have been severe. NASA has grounded all future shuttle flights until the falling foam problem can be made safer.
Jul 27, 2005 - NASA has confirmed that the space shuttle Discovery launched safely into orbit yesterday. During their 12-day mission to the International Space Station, Commander Eileen Collins and 6 other astronauts will test a series of techniques and equipment designed to make the shuttles safer. The crew of Discovery will spend seven hours today examining every inch of the shuttle with a camera attached to its robotic arm to look for any damage. The shuttle is expected to dock with the space station on Thursday.
Discovery Blasts Off Successfully
Jul 26, 2005 - After being grounded for more than two years, NASA's shuttle fleet has returned to service with today's dramatic launch of the space shuttle Discovery. It lifted off right on schedule, at 1439 UTC (10:39 am EDT), and quickly sped up through the light clouds above the Kennedy Space Center. More than 100 cameras were watching the launch from every available angle, and NASA will be examining the photographs carefully to see if any debris fell off the tank and struck the shuttle. Discovery will now link up with the International Space Station in a couple of days.
Jul 25, 2005 - NASA began the countdown for launch of the space shuttle Discovery on July 23. If all goes well, and there are no further delays, Discovery will blast off on Tuesday, July 26 at 1439 UTC (10:39 am EDT). They still have no resolution for the malfunctioning fuel gauge, but managers have said they'll be willing to let the shuttle fly, even if the problem resurfaces, because of redundant systems.
Jul 21, 2005 - Engineers are still working to troubleshoot a malfunctioning fuel gauge on the space shuttle Discovery's external tank, but NASA has pinned down a launch date anyway. If all goes well, Discovery is expected to lift off on Tuesday, July 26 at 1439 UTC (10:39 am EDT). Even if the fuel sensor fails again, managers will go ahead with the launch, as they don't believe there's a risk to the shuttle - there are 3 additional sensors that perform the same task.
Jul 20, 2005 - NASA is targeting July 26, 2005 as the earliest date for the space shuttle Discovery to return to flight. Engineers are still working through a troubleshooting plan to get to the bottom of a problem with a liquid hydrogen low-level sensor circuit that forced managers to abort the launch last week. Discovery's launch window lasts until July 31, and then opens up again in September.
Jul 18, 2005 - Space Shuttle managers have announced that Discovery won't be lifting off until late next week, at the earliest. Engineers and managers are still trying to troubleshoot exactly what caused a problem with the external tank's fuel gauge. It's possible that one of the new safety improvements, implemented as part of the Return to Flight effort might be causing the glitch. If the shuttle doesn't launch by July 31, it will need to wait again until September before there's another opportunity.
Jul 15, 2005 - NASA has announced that the space shuttle Discovery's earliest launch window will be on Sunday, July 17 at 1914 UTC (2:14 pm EDT); although, it could be much later. A problem with a fuel gauge on the shuttle's external tank halted the countdown on Wednesday. Engineers have so far been unable to find the source of the problem. The shuttle's launch window will last until the end of the July, and then opens up in September again.
Jul 14, 2005 - The return to flight launch of the space shuttle Discovery was delayed Wednesday when a faulty fuel gage failed a prelaunch check. The shuttle actually has four of these sensors for redundancy, but they all need to be working for the shuttle to get cleared for launch. The launch window has been pushed back to Saturday, July 16 at 1940 UTC (2:40 pm EDT). When it finally gets off the ground, Discovery will deliver supplies to the International Space Station and test new safety procedures developed for the Return to Flight.
Jul 8, 2005 - A new study by NASA and the Naval Research Institute has found that exhaust from the space shuttle can create high altitude clouds over Antarctica, just a few days after launch. Exhaust released at an altitude of 110 km (69 miles) can form Antarctic polar clouds in the mesosphere (the second highest layer of the atmosphere). Scientists originally discovered the connection when they noticed iron particles in clouds above Antarctica, and couldn't imagine a natural process that could put them into the high atmosphere.
Links For The Space Shuttle.All About The Space Shuttles - Learn the history behind each Space Shuttle including how they got their names.
Columbia & Challenger Memorial - A lasting tribute to the NASA astronauts of space shuttles Columbia and Challenger. America's heroes of space exploration.
Columbia Space Shuttle Tribute
How to get to Space View Park for Shuttle Launches.
Shuttle Press Kit
Shuttle Small Payloads Project
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