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Spaceflight is to travel in a spacecraft launched from the Earth.
A spaceflight is the sustained movement of a spacecraft into and through outer space. Spaceflights primarily use rockets technology for propulsion. A spaceflight begins with a launch, which provides the initial thrust to overcome the force of gravity and propel the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft -- both when unpropelled and when under propulsion -- is determined by astrodynamics.
Spaceflight is a necessary component of space exploration. Spaceflight is also necessary for commercial uses of space, such as space tourism and the launching of telecommunications satellites. Non-commercial uses of spaceflight include space observatories, reconnaissance satellites and other Earth observation satellites.
History of spaceflight.
The realistic proposal of space travel goes back to Konstantin Tsiolkovsky. His most famous work, The Exploration of Cosmic Space by Means of Reaction Devices, was published in 1903, but this theoretical work was not widely influential outside of Russia.
Spaceflight became an engineering possibility with the work of Robert H. Goddard's publication in 1919 of his paper 'A Method of Reaching Extreme Altitudes'; where his application of the de Laval nozzle to liquid fuel rockets gave sufficient power that interplanetary travel became possible. This paper was highly influential on Hermann Oberth and Wernher von Braun, later key players in spaceflight.
The first rocket to reach space was a prototype of the German V-2, on a test flight in 1942. In 1957 the Soviet Union launched Sputnik 1, which became the first artificial satellite to orbit the Earth. The first human spaceflight was Vostok 1 on April 12, 1961, aboard which Soviet cosmonaut Yuri Gagarin made one orbit around the Earth.
Rockets remain the only currently practical means of reaching space. Other technologies such as scramjets still fall far short of orbital speed, although show some potential.
The most commonly used definition of outer space is everything beyond the Kármán line, which is 100 kilometers (62.1 mi) above the Earth's surface. (The United States sometimes uses a 50 miles (80.5 km) definition.)
On a sub-orbital spaceflight the spacecraft reaches space, but does not achieve orbit. Instead, its trajectory brings it back to the surface of the Earth. Suborbital flights can last many hours. Pioneer 1 was NASA's first space probe, intended to reach the Moon. A partial failure caused it to instead follow a suborbital trajectory to an altitude of 113,854 kilometers (70,747.5 mi) before reentering the Earth's atmosphere 43 hours after launch.
On May 17, 2004, Civilian Space eXploration Team launched the GoFast Rocket on a suborbital flight, the first amateur space flight. On June 21, 2004, SpaceShipOne was used for the first privately-funded human spaceflight.
A minimal Orbital spaceflight requires very much higher velocities than a minimal sub-orbital flight, and so it is technologically much more challenging to achieve. To achieve orbital spaceflight, the tangential velocity around the Earth is just as important as height. In order to perform a stable and lasting flight in space, the velocity of the launched craft should be such that a closed orbit is possible.
Achieving a closed orbit is not essential to interplanetary voyages, for which spacecrafts need to reach escape velocity. Early Russian space vehicles successfully achieved very high altitudes without going into orbit. In its early Apollo mission planning NASA considered using a Direct Ascent to the moon, but abandoned that idea later due to weight considerations. Many unmanned space probes to the outer planets use direct ascent -- they do not orbit the earth before departing.
However, plans for future human spaceflight often include final vehicle assembly in Earth orbit.
Launch pads and Spaceports, takeoff
A launch pad is a fixed structure designed to dispatch airborne vehicles.
It generally consists of a launch tower and flame trench. It surrounded by equipment used to erect, fuel, and maintain launch vehicles.
A spaceport, by way of contrast, is designed to facilitate winged launch vehicles and uses a long runway.
Both spaceport and launch pads are situated well away from human habitation for noise and safety reasons.
Rockets run though a countdown sequence prior to Rocket launch.
A launch is often restricted to certain launch windows. These windows depend upon the position of celestial bodies and orbits relative to the launch site. The biggest influence is often the rotation of the Earth itself. Once launched, orbits are normally located within relatively constant flat planes at a fixed angle to the axis of the Earth, and the Earth rotates within this orbit.
Spaceflight: Reentry and landing/splashdown.
Vehicles in orbit have large amounts of kinetic energy. This energy must be discarded if the vehicle is to land safely without vaporizing in the atmosphere. Typically this process requires special methods to protect against aerodynamic heating. The theory behind reentry is due to Harry Julian Allen. Based on this theory, reentry vehicles present blunt shapes to the atmosphere for reentry. Blunt shapes mean that less than 1% of the kinetic energy ends up as heat that reaches the vehicle and the heat energy instead ends up in the atmosphere.
The Mercury, Gemini, and Apollo capsules all landed in the sea. These capsules were designed to land at relatively slow speeds. Russian capsules for Soyuz make use of braking rockets as were designed to touchdown on land. The Space Shuttle glides into a touchdown at high speed.
After a successful landing the spacecraft, its occupants, and cargo can be recovered. In some cases, recovery has occured before landing: while a spacecraft is still descending on its parachute, it can be snagged by a specially designed aircraft. This was the technique used to recover the film cannisters from the Corona spy satellites.
Spaceflight Expendable Launch Systems.
All current spaceflight except NASA's Space Shuttle and the SpaceX Falcon 1 use multi-stage expendable launch systems to reach space.
Spaceflight reusable launch systems.
The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963. The first partially reusable orbital spacecraft, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger when it was lost in January 1986. The Columbia broke up during reentry in February 2003.
The first (and so far only) automatic partially reusable spacecraft was the Buran (Snowstorm), launched by the USSR on November 15, 1988, although it made only one flight. This spaceplane was designed for a crew and strongly resembled the U. S. Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran.
Per the Vision for Space Exploration, the Space Shuttle is due to be retired in 2010 due mainly to its old age and high cost of the program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by the partially reusable Crew Exploration Vehicle (CEV) no later than 2014. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a Shuttle Derived Launch Vehicle.
Scaled Composites SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company will build its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic should begin reusable private spaceflight carrying paying passengers in 2008.
All launch vehicles contain a huge amount of energy that is needed for some part of it to reach orbit. There is therefore some risk that this energy can be released prematurely, with effects often comparable to a small atomic bomb. When an Delta II rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows 10 miles away being broken by the blast.
In addition, once in space, while space is a fairly predictable environment, there are risks of accidental depressurisation, and the potential for failure of equipment that is often very newly developed.
Spacecraft are vehicles capable of controlling their trajectory through space.
The first 'true spacecraft' is sometimes said to be Apollo Lunar Module since this was the only vehicle to have been designed for, and operated only in space; and is notable for its non aerodynamic shape.
Private versus Governmental spaceflight.
There is growing interest in spacecraft and flights paid for by commercial companies and even private individuals. It is thought that some of the high cost of access to space is due to governmental inefficiencies; and certainly the costs of the governmental paperwork surrounding NASA is legendary. If a commercial company were able to be more efficient costs could come down significantly. Space launch vehicles such as Falcon I have been wholly developed with private finance, and the quoted costs for launch are lower.
Human spaceflight: zero gravity.
Long term zero gravity exposure causes multiple health issues; most significantly bone loss, some of which is permanent, but also significant deconditioning of muscular and cardiovascular tissues.
Short term zero gravity causes space adaptation syndrome, a self-limiting nausea due to lack of gravity causing derangement of the vestibular system.
Life support: Interplanetary spaceflight: Interstellar spaceflight.
Travel between the stars in any reasonable time is extremely difficult due to the enormous distances involved. Our closest star (after the sun) is Proxima Centauri at over 4 light years away. The Voyager 1 space probe will take over 74,000 years at an average speed of 61,200 kmph (38,000 mph) to reach this distance. Vehicle designs using nuclear pulse propulsion might be able to reach the nearest star in a few decades however.
Astrodynamics of spaceflight.
Astrodynamics is the study of spacecraft trajectories, particularly as they relate to gravitational and propulsion effects. Astrodynamics allows for the spacecraft to arrive at their destination at the correct time; without excessive propellant use.
Spacecraft today predominantly use rockets for propulsion, but other propulsion techniques such as ion drives are becoming more common, particularly for unmanned vehicles, and this can significantly reduce the vehicle's mass and increase its delta-v.
More About Spaceflight.
Aug 29, 2005 - Wait, don't throw that garbage bag away. It might come in handy if you wanted to build a spaceship. At least, that's what NASA scientists working on new spacecraft materials are proposing. They've invented a new polyethylene-based material called RXF1 that's even stronger and lighter than aluminum. A plastic material like this is actually surprisingly protective against solar flares and cosmic rays since it doesn't produce "secondary radiation", like aluminum.
Aug 2, 2005 - One of the risks for sending humans to Mars is the lethal doses of radiation coming off the Sun in coronal mass ejections (CMEs). Researchers from the University of Warwick are proposing ways we can fill gaps in understanding about these processes and ensure astronaut safety. In addition to watching the far side of the Sun for CMEs, and developing detection equipment the astronauts can carry on their spacecraft, the researchers think we need to better understand how CMEs travel in the regions between Earth and Mars.
Jul 29, 2005 - Scaled Composite's Burt Rutan and entrepreneur Richard Branson announced this week that they have created a new company that will create a fleet of suborbital spacecraft. This new company will own the designs for SpaceShipTwo and its White Knight Two carrier aircraft. The company will manufacture the vehicles, and then sell them to suborbital spaceline operators, like Virgin Galactic.
Jul 28, 2005 - US entrepreneur Greg Olsen is going to get his trip to space after all. Space Adventures announced this week that Olsen will be joining the crew of the Soyuz TMA-7 spacecraft, currently scheduled for launch on October 1, 2005. Olsen will remain on board the station for 8 days, and run a few experiments on remote sensing and infrared astronomy - whenever he can drag himself away from the window. He was originally scheduled to fly much earlier, but Russian doctors forced a delay because of health concerns.
Jun 16, 2005 - Transformational Space Corp. successfully tested a scale model of its new booster design that should make launching humans into space less expensive and safer. A 1/5th scale mockup of the booster was flown aloft by Scaled Composite's Proteus aircraft and then dropped. The booster tilts itself vertically in midair so that it's pointing upward, without requiring any kind of wings. t/Space is one of eight companies chosen by NASA to develop techologies for the Crew Exploration Vehicle, which will return humans to the Moon as early as 2015.
Mar 22, 2005 - Once you're outside the Earth's atmosphere, you lose its protection from space debris. Small particles, no bigger than a few centimetres, are moving at such a velocity they can cause tremendous damage if they hit a satellite, or astronaut. When repairing the Hubble Space Telescope in 1993, astronauts discovered a hole blasted through an antenna, and numerous smaller pits and nicks. What strategies can mission planners employ to protect people and hardware in space?
Dec 9, 2004 - The U.S. Senate gave final congressional approval to the Commercial Space Launch Amendments Act (H.R. 5382) on Wednesday, which will allow private citizens to fly on suborbital launch vehicles at their own risk. Backers of this legislation said that it was necessary to encourage space tourism companies, like Richard Branson's Virgin Galactic, to risk making flights in the United States. Those opposed to the bill were concerned that regulators would have to stand by until someone actually got hurt before changing the rules.
Nov 22, 2004 - The US House of Representatives approved legislation on Saturday that would make regulations easier for companies looking to provide rides on private spacecraft. The vote for HR 5382 passed 269-120, which allows it to now go on for Senate approval, and finally to be signed by the President. This bill would streamline space tourism, allowing passengers to fly at their own risk, instead of forcing operators to take on excessive risk and insurance.
Nov 17, 2004 - The X-43A scramjet broke its own world record for air breathing engines on Tuesday, when it traveled at nearly 10 times the speed of sound. The prototype scramjet aircraft was dropped from a B-52 aircraft, and then boosted to Mach 4 by a Pegasus rocket. The aircraft detached from the rocket and then accelerated up to Mach 9.8 (11,265 kph or 7,000 mph). This flight was the last in a series of three test flights by NASA in the development of its Hyper-X program, which explores alternatives to rocket power for access to space.
Oct 4, 2004 - SpaceShipOne flew to space Monday morning, for the second time in less than a week. This time, though it came back down $10 million richer, taking the Ansari X-Prize. Pilot Brian Bennie guided the suborbital spacecraft to an altitude of more than 114 km (368,000 feet) after taking off from the Mojave Spaceport in California. Today's flight was completely smooth, without the terrifying series of barrel rolls at the highest point. Monday's flight was so high that it even beat records set by NASA's X-15 aircraft 40 years ago.
Oct 1, 2004 - X Prize officials have confirmed that Pilot Mike Melvill took Scaled Composites' SpaceShipOne to an altitude of 102, 870 metres (337,500 feet) on Wednesday. With this first flight qualified, they'll do their second flight on the morning Monday, October 4. SpaceShipOne and its carrier aircraft will take off at 1400 UTC (7:00am PDT) and ignite its rocket about an hour later. If everything goes well, the spacecraft will reach an altitude of 100 km (62.5 miles) carrying an extra 180 kg (400 pounds) - the equivalent of two passengers.
Sep 30, 2004 - travelling in space could be hard on your immune system, according to a new study funded by NASA. Researchers tested 25 astronauts before and after various space shuttle missions of varying lengths, and found that white blood cells increased after the astronauts returned from space. The increased number of white blood cells meant that the astronauts bodies were working overtime to fight off various microbes and diseases. And it appears that these effects probably increase as missions get longer and more difficult.
Sep 29, 2004 - It was a nailbiter this morning at the Mojave spaceport in California when SpaceShipOne successfully returned to space; half way to winning the $10 million X-Prize.
Sep 27, 2004 - Entrepreneur Richard Branson announced today that his company, Virgin Galactic, will be taking Scaled Composite's SpaceShipOne to the next logical step, and offer flights to the public. Virgin Galactic has ordered a larger version of the X-Prize contender suborbital spacecraft which will carry five passengers - the deal is reportedly worth $25 million over the next 14 years depending on how many ships are built. Tickets are expected to cost just over $200,000, and will include three-days of training, but industry experts expect the prices will come down with increased flight frequency.
Sep 24, 2004 - The da Vinci Project, a Canadian team of amateur rocket scientists, has pushed back the launch date of its Wildfire rocket. The Wildfire was originally scheduled to launch on October 2, which would put it only a few days after Scaled Composite's SpaceShipOne makes its launch attempt to win the $10 million X-Prize. The delay was required because the team was still waiting on some key components that they needed to install in the suborbital rocket. It's not known when they'll make their launch attempt.
Sep 14, 2004 - SpaceShipOne is getting a boost that will give it a little extra help winning the $10 million X-Prize: a bigger engine. Built by SpaceDev, this new hybrid rocket engine will burn stronger and a for a few seconds longer than the engine that took SpaceShipOne into space earlier this year. If all goes well, SpaceShipOne will make its first attempt on September 29 from the Mojave Spaceport in California. To win the $10 million prize, it'll need to be carrying the equivalent weight of three people, and then repeat the feat within two weeks.
Aug 10, 2004 - Another X Prize contender's rocket crashed over the weekend. Armadillo Aerospace's lead engineer and funder John Carmack reported that their prototype rocket ran out of fuel on a test flight and crashed shortly after takeoff. The $35,000 hydrogen peroxide-powered "Black Armadillo" lifted off from the launch pad and then ran out of fuel 180 metres (590 feet) into the air; it crashed into the ground and was completely destroyed. The team hopes to be flying again in September with a completely new vehicle.
Aug 10, 2004 - The Japanese Institute of Space and Astronautical Science has succeeded in launching and deploying the first ever solar sail into space. A solar sail is a thin metallic film pushed by light from the Sun - like a sail on Earth is pushed by the wind - it requires no engine. The 7.5 micrometers thick sail was carried on board an S-310 rocket launched from the Uchinoura Space Center, and deployed at 122 km (75 miles) altitude.
X Prize Contender's Rocket Explodes
Aug 9, 2004 - Space Transport Corp., a competitor for the $10 million Ansari X Prize, suffered a major setback on Sunday when their rocket - Rubicon 1 - exploded shortly after takeoff from a launch pad in Northwest Washington State. The 7-metre (23-foot) long spacecraft was supposed to go as high as 6.4 km (4 miles) and reach a speed of 1,800 kph (1,100 mph). One of the rocket's two engines exploded on the launch pad, but the second still carried it into the air, where it tore itself apart. Rubicon 1 has been developed on a shoestring budget - it only cost $20,000 - and another should be ready to go in the next month or so.
Aug 5, 2004 - The Canadian da Vinci Project has informed the Ansari X Prize of its plans to launch its Wild Fire rocket on October 2, 2004. This is the second team to announce a launch attempt, after Scaled Composite revealed they'll be launching SpaceShipOne on September 29. Wild Fire will be carried to altitude in Saskatchewan on board a giant balloon; it will detach and then fly up to 100 km (62.5 miles). The team announced a new sponsor, Internet casino GoldenPalace.com, which has provided cash in exchange for advertising.
Links For Spaceflight.Andoya Rocket Range
Centro de Lançamento de AlcÂntara
Geospace Environment Data Display System
Kennedy Space Center
Patrick Air Force Base
Poker Flat Research Range
Schriever Air Force Base, Colorado
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