Spaceflight

Spaceflight (also written space flight) is ballistic flight into or through outer space. Spaceflight can occur with spacecraft with or without humans on board. Yuri Gagarin of the Soviet Union was the first human to conduct a spaceflight. Examples of human spaceflight include the U.S. Apollo Moon landing and Space Shuttle programs and the Russian Soyuz program, as well as the ongoing International Space Station. Examples of unmanned spaceflight include space probes that leave Earth orbit, as well as satellites in orbit around Earth, such as communications satellites. These operate either by telerobotic control or are fully autonomous.

Spaceflight is used in space exploration, and also in commercial activities like space tourism and satellite telecommunications. Additional non-commercial uses of spaceflight include space observatories, reconnaissance satellites and other Earth observation satellites.

A spaceflight typically begins with a rocket launch, which provides the initial thrust to overcome the force of gravity and propels the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft – both when unpropelled and when under propulsion – is covered by the area of study called astrodynamics. Some spacecraft remain in space indefinitely, some disintegrate during atmospheric reentry, and others reach a planetary or lunar surface for landing or impact.

History

Konstantin Tsiolkovsky 1934
Tsiolkovsky, early space theorist

The first theoretical proposal of space travel using rockets was published by Scottish astronomer and mathematician William Leitch, in an 1861 essay "A Journey Through Space".[1] More well-known (though not widely outside Russia) is Konstantin Tsiolkovsky's work, "Исследование мировых пространств реактивными приборами" (The Exploration of Cosmic Space by Means of Reaction Devices), published in 1903.

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. His application of the de Laval nozzle to liquid fuel rockets improved efficiency enough for interplanetary travel to become possible. He also proved in the laboratory that rockets would work in the vacuum of space; nonetheless, his work was not taken seriously by the public. His attempt to secure an Army contract for a rocket-propelled weapon in the first World War was defeated by the November 11, 1918 armistice with Germany.

Nonetheless, Goddard's paper was highly influential on Hermann Oberth, who in turn influenced Wernher von Braun. Von Braun became the first to produce modern rockets as guided weapons, employed by Adolf Hitler. Von Braun's V-2 was the first rocket to reach space, at an altitude of 189 kilometers (102 nautical miles) on a June 1944 test flight.[2]

Tsiolkovsky's rocketry work was not fully appreciated in his lifetime, but he influenced Sergey Korolev, who became the Soviet Union's chief rocket designer under Joseph Stalin, to develop intercontinental ballistic missiles to carry nuclear weapons as a counter measure to United States bomber planes. Derivatives of Korolev's R-7 Semyorka missiles were used to launch the world's first artificial Earth satellite, Sputnik 1, on October 4, 1957, and later the first human to orbit the Earth, Yuri Gagarin in Vostok 1, on April 12, 1961.[3]

At the end of World War II, von Braun and most of his rocket team surrendered to the United States, and were expatriated to work on American missiles at what became the Army Ballistic Missile Agency. This work on missiles such as Juno I and Atlas enabled launch of the first US satellite Explorer 1 on February 1, 1958, and the first American in orbit, John Glenn in Friendship 7 on February 20, 1962. As director of the Marshall Space Flight Center, Von Braun oversaw development of a larger class of rocket called Saturn, which allowed the US to send the first two humans, Neil Armstrong and Buzz Aldrin, to the Moon and back on Apollo 11 in July 1969. Over the same period, the Soviet Union secretly tried but failed to develop the N1 rocket to give them the capability to land one person on the Moon.

Phases

Launch

Rockets are the only means currently capable of reaching orbit or beyond. Other non-rocket spacelaunch technologies have yet to be built, or remain short of orbital speeds. A rocket launch for a spaceflight usually starts from a spaceport (cosmodrome), which may be equipped with launch complexes and launch pads for vertical rocket launches, and runways for takeoff and landing of carrier airplanes and winged spacecraft. Spaceports are situated well away from human habitation for noise and safety reasons. ICBMs have various special launching facilities.

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.

A launch pad is a fixed structure designed to dispatch airborne vehicles. It generally consists of a launch tower and flame trench. It is surrounded by equipment used to erect, fuel, and maintain launch vehicles. Before launched, the rocket can way more than 2 million pounds. The Columbia, STS-1 weighed 4.4 million pounds at take off.

Reaching space

The most commonly used definition of outer space is everything beyond the Kármán line, which is 100 kilometers (62 mi) above the Earth's surface. The United States sometimes defines outer space as everything beyond 50 miles (80 km) in altitude.

Rockets are the only currently practical means of reaching space. Conventional airplane engines cannot reach space due to the lack of oxygen. Rocket engines expel propellant to provide forward thrust that generates enough delta-v (change in velocity) to reach orbit.

For manned launch systems launch escape systems are frequently fitted to allow astronauts to escape in the case of emergency.

Alternatives

Many ways to reach space other than rockets have been proposed. Ideas such as the space elevator, and momentum exchange tethers like rotovators or skyhooks require new materials much stronger than any currently known. Electromagnetic launchers such as launch loops might be feasible with current technology. Other ideas include rocket assisted aircraft/spaceplanes such as Reaction Engines Skylon (currently in early stage development), scramjet powered spaceplanes, and RBCC powered spaceplanes. Gun launch has been proposed for cargo.

Leaving orbit

RIAN archive 510848 Interplanetary station Luna 1 - blacked
Launched in 1959, Luna 1 was the first known man-made object to achieve escape velocity from the Earth.[4] (replica pictured)

Achieving a closed orbit is not essential to lunar and interplanetary voyages. Early Russian space vehicles successfully achieved very high altitudes without going into orbit. NASA considered launching Apollo missions directly into lunar trajectories but adopted the strategy of first entering a temporary parking orbit and then performing a separate burn several orbits later onto a lunar trajectory. This costs additional propellant because the parking orbit perigee must be high enough to prevent reentry while direct injection can have an arbitrarily low perigee because it will never be reached.

However, the parking orbit approach greatly simplified Apollo mission planning in several important ways. It substantially widened the allowable launch windows, increasing the chance of a successful launch despite minor technical problems during the countdown. The parking orbit was a stable "mission plateau" that gave the crew and controllers several hours to thoroughly check out the spacecraft after the stresses of launch before committing it to a long lunar flight; the crew could quickly return to Earth, if necessary, or an alternate Earth-orbital mission could be conducted. The parking orbit also enabled translunar trajectories that avoided the densest parts of the Van Allen radiation belts.

Apollo missions minimized the performance penalty of the parking orbit by keeping its altitude as low as possible. For example, Apollo 15 used an unusually low parking orbit (even for Apollo) of 92.5 nmi by 91.5 nmi (171 km by 169 km) where there was significant atmospheric drag. But it was partially overcome by continuous venting of hydrogen from the third stage of the Saturn V, and was in any event tolerable for the short stay.

Robotic missions do not require an abort capability or radiation minimization, and because modern launchers routinely meet "instantaneous" launch windows, space probes to the Moon and other planets generally use direct injection to maximize performance. Although some might coast briefly during the launch sequence, they do not complete one or more full parking orbits before the burn that injects them onto an Earth escape trajectory.

Note that the escape velocity from a celestial body decreases with altitude above that body. However, it is more fuel-efficient for a craft to burn its fuel as close to the ground as possible; see Oberth effect and reference.[5] This is another way to explain the performance penalty associated with establishing the safe perigee of a parking orbit.

Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA's Project Orion and Russia's Kliper/Parom tandem.

Astrodynamics

Astrodynamics is the study of spacecraft trajectories, particularly as they relate to gravitational and propulsion effects. Astrodynamics allows for a spacecraft to arrive at its destination at the correct time without excessive propellant use. An orbital maneuvering system may be needed to maintain or change orbits.

Non-rocket orbital propulsion methods include solar sails, magnetic sails, plasma-bubble magnetic systems, and using gravitational slingshot effects.

Space Shuttle Atlantis in the sky on July 21, 2011, to its final landing
Ionized gas trail from Shuttle reentry
Keyhole capsule recovery
Recovery of Discoverer 14 return capsule by a C-119 airplane

Transfer energy

The term "transfer energy" means the total amount of energy imparted by a rocket stage to its payload. This can be the energy imparted by a first stage of a launch vehicle to an upper stage plus payload, or by an upper stage or spacecraft kick motor to a spacecraft.[6][7]

Reentry

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 was developed by 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 remainder heats up the atmosphere.

Landing

The Mercury, Gemini, and Apollo capsules all splashed down in the sea. These capsules were designed to land at relatively low speeds with the help of a parachute. Russian capsules for Soyuz make use of a big parachute and braking rockets to touch down on land. The Space Shuttle glided to a touchdown like a plane.

Recovery

After a successful landing the spacecraft, its occupants and cargo can be recovered. In some cases, recovery has occurred before landing: while a spacecraft is still descending on its parachute, it can be snagged by a specially designed aircraft. This mid-air retrieval technique was used to recover the film canisters from the Corona spy satellites.

Types

Uncrewed

Pathfinder01
Sojourner takes its APXS measurement of the Yogi Rock.
Messenger
The MESSENGER spacecraft at Mercury (artist's interpretation)

Uncrewed spaceflight (or unmanned) is all spaceflight activity without a necessary human presence in space. This includes all space probes, satellites and robotic spacecraft and missions. Uncrewed spaceflight is the opposite of manned spaceflight, which is usually called human spaceflight. Subcategories of uncrewed spaceflight are "robotic spacecraft" (objects) and "robotic space missions" (activities). A robotic spacecraft is an uncrewed spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe.

Uncrewed space missions use remote-controlled spacecraft. The first uncrewed space mission was Sputnik I, launched October 4, 1957 to orbit the Earth. Space missions where animals but no humans are on-board are considered uncrewed missions.

Benefits

Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are the only way to explore them. Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized. Humans can not be sterilized in the same way as a spaceship, as they coexist with numerous micro-organisms, and these micro-organisms are also hard to contain within a spaceship or spacesuit.

Telepresence

Telerobotics becomes telepresence when the time delay is short enough to permit control of the spacecraft in close to real time by humans. Even the two seconds light speed delay for the Moon is too far away for telepresence exploration from Earth. The L1 and L2 positions permit 400-millisecond round trip delays, which is just close enough for telepresence operation. Telepresence has also been suggested as a way to repair satellites in Earth orbit from Earth. The Exploration Telerobotics Symposium in 2012 explored this and other topics.[8]

Human

ISS-20 Robert Thirsk at the Minus Eighty Degree Laboratory Freezer
ISS crew member stores samples

The first human spaceflight was Vostok 1 on April 12, 1961, on which cosmonaut Yuri Gagarin of the USSR made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles.[9] Currently, the only spacecraft regularly used for human spaceflight are the Russian Soyuz spacecraft and the Chinese Shenzhou spacecraft. The U.S. Space Shuttle fleet operated from April 1981 until July 2011. SpaceShipOne has conducted two human suborbital spaceflights.

Sub-orbital

STS-119 Flyaround (Low Resolution)
The International Space Station in Earth orbit after a visit from the crew of STS-119

On a sub-orbital spaceflight the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficient specific orbital energy, in which case a suborbital flight will last only a few minutes, but it is also possible for an object with enough energy for an orbit to have a trajectory that intersects the Earth's atmosphere, sometimes after 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 (70,746 mi) before reentering the Earth's atmosphere 43 hours after launch.

The most generally recognized boundary of space is the Kármán line 100 km above sea level. (NASA alternatively defines an astronaut as someone who has flown more than 50 miles (80 km) above sea level.) It is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there. On May 17, 2004, Civilian Space eXploration Team launched the GoFast Rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004, SpaceShipOne was used for the first privately funded human spaceflight.

Point-to-point

Point-to-point is a category of sub-orbital spaceflight in which a spacecraft provides rapid transport between two terrestrial locations. Consider a conventional airline route between London and Sydney, a flight that normally lasts over twenty hours. With point-to-point suborbital travel the same route could be traversed in less than one hour.[10] While no company offers this type of transportation today, SpaceX has revealed plans to do so as early as the 2020s using its BFR vehicle.[11] Suborbital spaceflight over an intercontinental distance requires a vehicle velocity that is only a little lower than the velocity required to reach low Earth orbit.[12] If rockets are used, the size of the rocket relative to the payload is similar to an Intercontinental Ballistic Missile (ICBM). Any intercontinental spaceflight has to surmount problems of heating during atmosphere re-entry that are nearly as large as those faced by orbital spaceflight.

Orbital

S68-27366
Apollo 6 heads into orbit

A minimal orbital spaceflight requires 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 as important as altitude. In order to perform a stable and lasting flight in space, the spacecraft must reach the minimal orbital speed required for a closed orbit.

Interplanetary

Interplanetary travel is travel between planets within a single planetary system. In practice, the use of the term is confined to travel between the planets of our Solar System.

Interstellar

Five spacecraft are currently leaving the Solar System on escape trajectories, Voyager 1, Voyager 2, Pioneer 10, Pioneer 11, and New Horizons. The one farthest from the Sun is Voyager 1, which is more than 100 AU distant and is moving at 3.6 AU per year.[13] In comparison, Proxima Centauri, the closest star other than the Sun, is 267,000 AU distant. It will take Voyager 1 over 74,000 years to reach this distance. Vehicle designs using other techniques, such as nuclear pulse propulsion are likely to be able to reach the nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use of time dilation, as this would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. However, attaining such high speeds would still require the use of some new, advanced method of propulsion.

Intergalactic

Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is considered science fiction.

Spacecraft

Apollo16LM
An Apollo Lunar Module on the lunar surface

Spacecraft are vehicles capable of controlling their trajectory through space.

The first 'true spacecraft' is sometimes said to be Apollo Lunar Module,[14] since this was the only manned vehicle to have been designed for, and operated only in space; and is notable for its non aerodynamic shape.

Propulsion

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.

Launch systems

Launch systems are used to carry a payload from Earth's surface into outer space.

Expendable

All current spaceflight uses multi-stage expendable launch systems to reach space.

Reusable

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, which was lost in January 1986. The Columbia broke up during reentry in February 2003.
Space Shuttle Columbia launching
The Space Shuttle Columbia seconds after engine ignition on mission STS-1
Columbia landing on Rogers dry lake.triddle
Columbia landing, concluding the STS-1 mission
Columbia launch 1981
Columbia launches again on STS-2
The first 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 US 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 was retired in 2011 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 2021. 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 planned to begin reusable private spaceflight carrying paying passengers (space tourists) in 2008, but this was delayed due to an accident in the propulsion development.[15]

Challenges

Space disasters

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 and suddenly, with significant effects. When a Delta II rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows 10 miles (16 km) away being broken by the blast.[16]

Space is a fairly predictable environment, but there are still risks of accidental depressurization and the potential failure of equipment, some of which may be very newly developed.

In 2004 the International Association for the Advancement of Space Safety was established in the Netherlands to further international cooperation and scientific advancement in space systems safety.[17]

Weightlessness

Foale ZeroG
Astronauts on the ISS in weightless conditions. Michael Foale can be seen exercising in the foreground.

In a microgravity environment such as that provided by a spacecraft in orbit around the Earth, humans experience a sense of "weightlessness." Short-term exposure to microgravity causes space adaptation syndrome, a self-limiting nausea caused by derangement of the vestibular system. Long-term exposure causes multiple health issues. The most significant is bone loss, some of which is permanent, but microgravity also leads to significant deconditioning of muscular and cardiovascular tissues.

Radiation

Once above the atmosphere, radiation due to the Van Allen belts, solar radiation and cosmic radiation issues occur and increase. Further away from the Earth, solar flares can give a fatal radiation dose in minutes, and the health threat from cosmic radiation significantly increases the chances of cancer over a decade exposure or more.[18]

Life support

In human spaceflight, the life support system is a group of devices that allow a human being to survive in outer space. NASA often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for its human spaceflight missions.[19] The life support system may supply: air, water and food. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are life-critical, and are designed and constructed using safety engineering techniques.

Space weather

Space weather is the concept of changing environmental conditions in outer space. It is distinct from the concept of weather within a planetary atmosphere, and deals with phenomena involving ambient plasma, magnetic fields, radiation and other matter in space (generally close to Earth but also in interplanetary, and occasionally interstellar medium). "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the Sun, the nature of Earth's magnetic field, and our location in the Solar System."[20]

Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude in Low Earth orbit. Geomagnetic storms due to increased solar activity can potentially blind sensors aboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for manned spacecraft.

Environmental considerations

Rockets as a class are not inherently grossly polluting. However, some rockets use toxic propellants, and most vehicles use propellants that are not carbon neutral. Many solid rockets have chlorine in the form of perchlorate or other chemicals, and this can cause temporary local holes in the ozone layer. Re-entering spacecraft generate nitrates which also can temporarily impact the ozone layer. Most rockets are made of metals that can have an environmental impact during their construction.

In addition to the atmospheric effects there are effects on the near-Earth space environment. There is the possibility that orbit could become inaccessible for generations due to exponentially increasing space debris caused by spalling of satellites and vehicles (Kessler syndrome). Many launched vehicles today are therefore designed to be re-entered after use.

Applications

S74-15583skylabsunview
This shows an extreme ultraviolet view of the sun (the Apollo Telescope Mount SO82A Experiment) taken during Skylab 3, with the Earth added for scale. On the right an image of the Sun shows a helium emissions, and there is an image on the left showing emissions from iron. One application for spaceflight is to take observation hindered or made more difficult by being on Earth's surface. Skylab included a massive manned solar observatory that revolutionized solar science in the early 1970s using the Apollo-based space station in conjunction with manned spaceflights to it.

Current and proposed applications for spaceflight include:

Most early spaceflight development was paid for by governments. However, today major launch markets such as Communication satellites and Satellite television are purely commercial, though many of the launchers were originally funded by governments.

Private spaceflight is a rapidly developing area: space flight that is not only paid for by corporations or even private individuals, but often provided by private spaceflight companies. These companies often assert that much of the previous high cost of access to space was caused by governmental inefficiencies they can avoid. This assertion can be supported by much lower published launch costs for private space launch vehicles such as Falcon 9 developed with private financing. Lower launch costs and excellent safety will be required for the applications such as Space tourism and especially Space colonization to become successful.

See also

References

  1. ^ William Leitch (1867). God's Glory in the Heavens. A. Strahan.
  2. ^ Lucy Rogers (2008). It's ONLY Rocket Science: An Introduction in Plain English. Springer Science & Business Media. p. 25. ISBN 978-0-387-75377-5.
  3. ^ Peter Bond, Obituary: Lt-Gen Kerim Kerimov, The Independent, 7 April 2003.
  4. ^ "NASA – NSSDC – Spacecraft – Details". Nssdc.gsfc.nasa.gov. Retrieved November 5, 2013.
  5. ^ Escape Velocity of Earth. Van.physics.uiuc.edu. Retrieved on 2011-10-05.
  6. ^ Lance K. Erickson (2010). Space Flight: History, Technology, and Operations. Government Institutes. p. 187.
  7. ^ "Musk pre-launch backgrounder on Falcon 9 Flight 20". SpaceX press release. 22 December 2015. Retrieved 28 December 2015.
  8. ^ Exploration Telerobotics Symposium Archived 2015-07-05 at the Wayback Machine May 2–3, 2012 at NASA Goddard Space Flight Center.
  9. ^ Vostok 1. Astronautix.com. Retrieved on 2011-10-05.
  10. ^ "Becoming a Multiplanet Species" (PDF). 68th annual meeting of the International Astronautical Congress in Adelaide, Australia: SpaceX. 29 September 2017.
  11. ^ Elon Musk (29 September 2017). Becoming a Multiplanet Species (video). 68th annual meeting of the International Astronautical Congress in Adelaide, Australia: SpaceX. Retrieved 14 December 2017 – via YouTube.
  12. ^ David HoerrMonday, May 5, 2008 (May 5, 2008). "Point-to-point suborbital transportation: sounds good on paper, but…". The Space Review. Retrieved November 5, 2013.CS1 maint: Multiple names: authors list (link)
  13. ^ "Spacecraft escaping the Solar System". Heavens-Above GmbH. Archived from the original on April 27, 2007.
  14. ^ Apollo Expeditions to the Moon: Chapter 10. History.nasa.gov (1969-03-03). Retrieved on 2011-10-05.
  15. ^ Launch aircraft development continues while suborbital ship awaits investigation into fatal explosion in California, retrieved 2012-01-27.
  16. ^ "Unmanned rocket explodes after liftoff". CNN.
  17. ^ "The second IAASS: Introduction". Congrex. European Space Agency. Archived from the original on 24 July 2012. Retrieved 3 January 2009.
  18. ^ Super Spaceships, NASA, 16 September 2002, Retrieved 25 October 2011.
  19. ^ "Breathing Easy on the Space Station". NASA. Archived from the original on 2008-09-21.
  20. ^ Space Weather: A Research Perspective, National Academy of Science, 1997

Further reading

  • Erik Gregerson (2010): An Explorer's Guide to the Universe – Unmanned Space Missions, Britannica Educational Publishing, ISBN 978-1-61530-052-5 (eBook)

External links

CU Spaceflight

CU Spaceflight is a student-run Cambridge University society founded with the aim of achieving cheap access to space. It is supported by the Cambridge-MIT Institute.

Effect of spaceflight on the human body

Venturing into the environment of space can have negative effects on the human body. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton (spaceflight osteopenia). Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance disorders, eyesight disorders and changes in the immune system. Additional symptoms include fluid redistribution (causing the "moon-face" appearance typical in pictures of astronauts experiencing weightlessness), loss of body mass, nasal congestion, sleep disturbance, and excess flatulence.

The engineering problems associated with leaving Earth and developing space propulsion systems have been examined for over a century, and millions of man-hours of research have been spent on them. In recent years there has been an increase in research on the issue of how humans can survive and work in space for extended and possibly indefinite periods of time. This question requires input from the physical and biological sciences and has now become the greatest challenge (other than funding) facing human space exploration. A fundamental step in overcoming this challenge is trying to understand the effects and impact of long-term space travel on the human body.

In October 2015, the NASA Office of Inspector General issued a health hazards report related to space exploration, including a human mission to Mars.On 12 April 2019, NASA reported medical results, from the Astronaut Twin Study, where one astronaut twin spent a year in space on the International Space Station, while the other twin spent the year on Earth, which demonstrated several long-lasting changes, including those related to alterations in DNA and cognition, when one twin was compared with the other.

Human spaceflight

Human spaceflight (also referred to as crewed spaceflight or manned spaceflight) is space travel with a crew or passengers aboard the spacecraft. Spacecraft carrying people may be operated directly, by human crew, or it may be either remotely operated from ground stations on Earth or be autonomous, able to carry out a specific mission with no human involvement.

The first human spaceflight was launched by the Soviet Union on 12 April 1961 as a part of the Vostok program, with cosmonaut Yuri Gagarin aboard. Humans have been continuously present in space for 18 years and 174 days on the International Space Station. All early human spaceflight was crewed, where at least some of the passengers acted to carry out tasks of piloting or operating the spacecraft. After 2015, several human-capable spacecraft are being explicitly designed with the ability to operate autonomously.

Russia and China have human spaceflight capability with the Soyuz program and Shenzhou program. In the United States, SpaceShipTwo reached the edge of space in 2018; this was the first crewed spaceflight from the USA since the Space Shuttle retired in 2011. Currently, all expeditions to the International Space Station use Soyuz vehicles, which remain attached to the station to allow quick return if needed. The United States is developing commercial crew transportation to facilitate domestic access to ISS and low Earth orbit, as well as the Orion vehicle for beyond-low-Earth-orbit applications.

While spaceflight has typically been a government-directed activity, commercial spaceflight has gradually been taking on a greater role. The first private human spaceflight took place on 21 June 2004, when SpaceShipOne conducted a suborbital flight, and a number of non-governmental companies have been working to develop a space tourism industry. NASA has also played a role to stimulate private spaceflight through programs such as Commercial Orbital Transportation Services (COTS) and Commercial Crew Development (CCDev). With its 2011 budget proposals released in 2010, the Obama administration moved towards a model where commercial companies would supply NASA with transportation services of both people and cargo transport to low Earth orbit. The vehicles used for these services could then serve both NASA and potential commercial customers. Commercial resupply of ISS began two years after the retirement of the Shuttle, and commercial crew launches could begin by 2019.

Indian Human Spaceflight Programme

The Indian Human Spaceflight Programme (HSP) was created by the Indian Space Research Organisation (ISRO) to develop the technology needed to launch crewed orbital spacecraft into low Earth orbit. The first crewed flight is planned with a spacecraft called Gaganyaan for December 2021 on a home-grown GSLV-III rocket.Before Gaganyaan mission announcement in August 2018, human spaceflight was not the priority for ISRO, though most of the required capability for it had been realised. ISRO has already developed most of the technologies for crewed flight and it performed a Crew Module Atmospheric Re-entry Experiment and a Pad Abort Test for the mission. The project will cost less than Rs. 10,000 crore. In December 2018, the government approved further ₹ 100 billion (US$1.5 billion) for a 7-days crewed flight of 3 astronauts to take place in December, 2021.If completed on schedule, India will become world's fourth nation to conduct independent human spaceflight after the Soviet Union/Russia, United States and People's Republic of China. After conducting crewed spaceflights, the agency also intends to continue with efforts with a space station program and possibly a crewed lunar landing.

Jim Lovell

James Arthur Lovell Jr. (; born March 25, 1928) is a former NASA astronaut, Naval Aviator, and retired Navy captain. Lovell is known for being the commander of the ill-fated Apollo 13 mission, which suffered a critical failure en route to the Moon but was brought back safely to Earth through the efforts of the crew and mission control. In addition to being part of the Apollo 13 crew, Lovell was the command module pilot of Apollo 8, the first Apollo mission to enter lunar orbit.

He is one of only 24 people to have flown to the Moon and the first of only three people to fly to the Moon twice as well as the only one to have flown there twice without making a landing. Lovell was the first person to fly in space four times.

He is a recipient of the Congressional Space Medal of Honor and the Presidential Medal of Freedom (in 1970, one of 17 recipients in the group Space Exploration).

Johnson Space Center

The Lyndon B. Johnson Space Center (JSC) is the National Aeronautics and Space Administration's Manned Spacecraft Center, where human spaceflight training, research, and flight control are conducted. It was built and leased to NASA by Joseph L. Smith & Associates, Inc. It was renamed in honor of the late U.S. president and Texas native, Lyndon B. Johnson, by an act of the United States Senate on February 19, 1973.

It consists of a complex of 100 buildings constructed on 1,620 acres (660 hectares) in the Clear Lake Area of Houston, which acquired the official nickname "Space City" in 1967. The center is home to NASA's astronaut corps, and is responsible for training astronauts from both the U.S. and its international partners. It has become popularly known for its flight control function, identified as "Mission Control" and "Houston" during the Gemini, Apollo, Skylab, Apollo–Soyuz, and Space Shuttle program flights.

The Manned Spacecraft Center grew out of the Space Task Group (STG) headed by Robert Gilruth, formed soon after the creation of NASA to co-ordinate the US manned spaceflight program. The STG was based at the Langley Research Center in Hampton, Virginia, but reported organizationally to the Goddard Space Flight Center just outside Washington, D.C. To meet the growing needs of the US human spaceflight program, plans began in 1961 to expand its staff to its own organization, and move it to a new facility. This was constructed in 1962 and 1963 on land donated by the Humble Oil company through Rice University, and officially opened its doors in September 1963. Today, JSC is one of ten major NASA field centers.

Laika

Laika (Russian: Лайка; c. 1954 – 3 November 1957) was a Soviet space dog who became one of the first animals in space, and the first animal to orbit the Earth. Laika, a stray mongrel from the streets of Moscow, was selected to be the occupant of the Soviet spacecraft Sputnik 2 that was launched into outer space on 3 November 1957.

Little was known about the impact of spaceflight on living creatures at the time of Laika's mission, and the technology to de-orbit had not yet been developed, so Laika's survival was never expected. Some scientists believed humans would be unable to survive the launch or the conditions of outer space, so engineers viewed flights by animals as a necessary precursor to human missions. The experiment aimed to prove that a living passenger could survive being launched into orbit and endure a micro-g environment, paving the way for human spaceflight and providing scientists with some of the first data on how living organisms react to spaceflight environments.

Laika died within hours from overheating, possibly caused by a failure of the central R-7 sustainer to separate from the payload. The true cause and time of her death were not made public until 2002; instead, it was widely reported that she died when her oxygen ran out on day six or, as the Soviet government initially claimed, she was euthanised prior to oxygen depletion.

On 11 April 2008, Russian officials unveiled a monument to Laika. A small monument in her honour was built near the military research facility in Moscow that prepared Laika's flight to space. It portrayed a dog standing on top of a rocket. She also appears on the Monument to the Conquerors of Space in Moscow.

List of human spaceflights

This is a list of all human spaceflights throughout history. Beginning in 1961 with the flight of Yuri Gagarin aboard Vostok 1, human spaceflight occurs when a human crew flies a spacecraft into outer space. Human spaceflight is distinguished from spaceflight generally, which entails both crewed and uncrewed spacecraft.

There are two definitions of spaceflight. The Fédération Aéronautique Internationale (FAI), an international record-keeping body, defines the boundary between Earth's atmosphere and outer space at 100 kilometers above sea level. This boundary is known as the Kármán line. Additionally, the United States military awards astronaut wings to qualified personnel who pilot a spaceflight above an altitude of 50 miles (80 km). Thirteen flights of the North American X-15 met the latter criteria, while only two met the former. This article is primarily concerned with the former international convention, and also lists flights which only satisfied the latter convention. Unless otherwise specified, "spaceflight" and related terms only apply to flights which went beyond the Kármán line.

As of the launch of Soyuz MS-12 on 14 March 2019, there have been 325 human spaceflight launch attempts, including three failed attempts which did not cross the Kármán line. These were the fatal Challenger disaster, and two non-fatal aborted Soyuz missions, T-10a and MS-10. Another non-fatal aborted Soyuz mission, 18a, nevertheless crossed the Kármán line and therefore qualified as a sub-orbital spaceflight. Three missions successfully achieved human spaceflight, yet ended as fatal failures as their crews died during the return. These were Soyuz 1, Soyuz 11, and the Columbia disaster. Uniquely, Soyuz 34 was launched uncrewed to the Salyut 6 space station, to provide a successful return vehicle for the crew of Soyuz 32. Including Soyuz 34 gives a total of 326 attempted human spaceflights. 14 flights reached an apogee beyond 50 miles, but failed to go beyond 100 kilometers.

List of spaceflight-related accidents and incidents

This article lists verifiable spaceflight-related accidents and incidents resulting in fatality or near-fatality during flight or training for manned space missions, and testing, assembly, preparation or flight of manned and unmanned spacecraft. Not included are accidents or incidents associated with intercontinental ballistic missile (ICBM) tests, unmanned space flights not resulting in fatality or serious injury, or Soviet or German rocket-powered aircraft projects of World War II. Also not included are alleged unreported Soviet space accidents, which are considered fringe theories by a majority of historians.

As of 2018, there have been 18 astronaut and cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three. There have also been some non-astronaut fatalities during spaceflight-related activities.

List of spaceflight records

This is a list of spaceflight records. Most of these records relate to human spaceflights, but some unmanned and animal records are listed as well.

Orbital spaceflight

An orbital spaceflight (or orbital flight) is a spaceflight in which a spacecraft is placed on a trajectory where it could remain in space for at least one orbit. To do this around the Earth, it must be on a free trajectory which has an altitude at perigee (altitude at closest approach) above 100 kilometers (62 mi); this is, by at least one convention, the boundary of space. To remain in orbit at this altitude requires an orbital speed of ~7.8 km/s. Orbital speed is slower for higher orbits, but attaining them requires greater delta-v.

Due to atmospheric drag, the lowest altitude at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately 150 kilometres (93 mi).

The expression "orbital spaceflight" is mostly used to distinguish from sub-orbital spaceflights, which are flights where the apogee of a spacecraft reaches space, but the perigee is too low.

Private spaceflight

Private spaceflight is a spaceflight or the development of new spaceflight technology that is conducted and paid for by an entity other than a government agency.

In the early decades of the Space Age, the government space agencies of the Soviet Union and United States pioneered space technology in collaboration with affiliated design bureaus in the USSR and private companies in the US, entirely funding both the development of new spaceflight technologies and the operational costs of spaceflight. The European Space Agency was formed in 1975, largely following the same model of space technology development.

Later on, large defense contractors began to develop and operate space launch systems, derived from government rockets. Private spaceflight in Earth orbit includes communications satellites, satellite television, satellite radio, astronaut transport and sub-orbital and orbital space tourism.

In the 2000s, entrepreneurs began designing—and by the 2010s, deploying—space systems competitive to the national-monopoly governmental systems of the early decades of the space age. These new offerings have brought about significant market competition in space launch services after 2010 that had not been present previously.

Successes to date include flying suborbital spaceplanes, launching orbital rockets, flying two orbital expandable test modules (Genesis I and II), and the successful development of first-stage orbital launch vehicles that are able to vertically land after a launch so as to enable reuse. The most powerful rocket in operation as of 2018, the Falcon Heavy, was privately developed.

Planned private spaceflights beyond Earth orbit include personal spaceflights around the Moon. Two private orbital habitat prototypes are already in Earth orbit, with larger versions to follow. Planned private spaceflights beyond Earth orbit include solar sailing prototypes (LightSail-3).

Robotic spacecraft

A robotic spacecraft is an uncrewed spacecraft, usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spacecraft technology, so telerobotic probes are the only way to explore them.

Many artificial satellites are robotic spacecraft, as are many landers and rovers.

Saturn V

The Saturn V (pronounced "Saturn five") was an American human-rated expendable rocket used by NASA between 1967 and 1973. The three-stage liquid-propellant super heavy-lift launch vehicle was developed to support the Apollo program for human exploration of the Moon and was later used to launch Skylab, the first American space station.

The Saturn V was launched 13 times from the Kennedy Space Center in Florida with no loss of crew or payload. As of 2019, the Saturn V remains the tallest, heaviest, and most powerful (highest total impulse) rocket ever brought to operational status, and holds records for the heaviest payload launched and largest payload capacity to low Earth orbit (LEO) of 140,000 kg (310,000 lb), which included the third stage and unburned propellant needed to send the Apollo Command/Service Module and Lunar Module to the Moon.The largest production model of the Saturn family of rockets, the Saturn V was designed under the direction of Wernher von Braun and Arthur Rudolph at the Marshall Space Flight Center in Huntsville, Alabama, with Boeing, North American Aviation, Douglas Aircraft Company, and IBM as the lead contractors.

To date, the Saturn V remains the only launch vehicle to carry humans beyond low Earth orbit. A total of 15 flight-capable vehicles were built, but only 13 were flown. An additional three vehicles were built for ground testing purposes. A total of 24 astronauts were launched to the Moon, three of them twice, in the four years spanning December 1968 through December 1972.

Soyuz (rocket family)

Soyuz (Russian: Союз, meaning "union", GRAU index 11A511) is a family of expendable launch systems developed by OKB-1 and manufactured by Progress Rocket Space Centre in Samara, Russia. With over 1700 flights since its debut in 1966, the Soyuz is the most frequently used launch vehicle in the world.When the U.S. Space Shuttle program ended in 2011, Soyuz rockets became the only launch vehicles able to transport astronauts to the International Space Station.

The Soyuz vehicles are used as the launcher for the crewed Soyuz spacecraft as part of the Soyuz program, as well as to launch uncrewed Progress supply spacecraft to the International Space Station and for commercial launches marketed and operated by Starsem and Arianespace. All Soyuz rockets use RP-1 and liquid oxygen (LOX) propellant, with the exception of the Soyuz-U2, which used Syntin, a variant of RP-1, with LOX. The Soyuz family is a subset of the R-7 family.

Sub-orbital spaceflight

A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the atmosphere or surface of the gravitating body from which it was launched, so that it will not complete one orbital revolution.

For example, the path of an object launched from Earth that reaches the Kármán line (at 100 km (62 mi) above sea level), and then falls back to Earth, is considered a sub-orbital spaceflight. Some sub-orbital flights have been undertaken to test spacecraft and launch vehicles later intended for orbital spaceflight. Other vehicles are specifically designed only for sub-orbital flight; examples include manned vehicles, such as the X-15 and SpaceShipOne, and unmanned ones, such as ICBMs and sounding rockets.

Flights which attain sufficient velocity to go into low Earth orbit, and then de-orbit before completing their first full orbit, are not considered sub-orbital. Examples of this include Yuri Gagarin's Vostok 1, and flights of the Fractional Orbital Bombardment System.

Usually a rocket is used, but experimental sub-orbital spaceflight has also been achieved with a space gun.

Timeline of spaceflight

This is a timeline of known spaceflights, both crewed and uncrewed, sorted chronologically by launch date. Owing to its large size, the timeline is split into smaller articles, one for each year since 1951. There is a separate list for all flights that occurred before 1951.

The 2019 list, and lists for subsequent years, contain planned launches which have not yet occurred.

For the purpose of these lists, a spaceflight is defined as any flight that crosses the Kármán line, the officially recognised edge of space, which is 100 kilometres (62 miles) above mean sea level (AMSL). The timeline contains all flights which have crossed the edge of space, were intended to do so but failed, or are planned in the near future. Some lists are further divided into orbital launches (sending a payload into orbit, whether successful or not) and suborbital flights (e.g. ballistic missiles, sounding rockets, experimental spacecraft).

Voskhod (rocket)

The Voskhod rocket (Russian: Восход, "ascent", "dawn") was a derivative of the Soviet R-7 ICBM designed for the human spaceflight programme but later used for launching Zenit reconnaissance satellites. It consisted of the Molniya 8K78M third stage minus the Blok L. In 1966, all R-7 variants were equipped with the uprated core stage and strap-ons of the Soyuz 11A511. The Blok I stage in the Voskhod booster used the RD-107 engine rather than the RD-110 in the Soyuz, which was more powerful and also man-rated. The sole exception to this were the two manned Voskhod launches, which had RD-108 engines, a man-rated RD-107 but with the same performance.

All 11A57s launched after 1965 were functionally an 11A511 without the Soyuz's payload shroud and launch escape system (with the exception of the third stage propulsion system as noted above). Around 300 were flown from Baikonur and Plesetsk through 1976 (various payloads, but Zenith PHOTINT satellites were the most common). The newer 11A511U core had been introduced in 1973, but the existing stock of 11A57s took another three years to use up.

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