Spaceflight osteopenia refers to the characteristic bone loss that occurs during spaceflight. Astronauts lose an average of more than 1% bone mass per month spent in space. There is concern that during long duration flights, excessive bone loss and the associated increase in serum calcium ion levels will interfere with execution of mission tasks and result in irreversible skeletal damage.

Adapted from the Wikipedia article Spaceflight osteopenia, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Spaceflight or space flight is the use of space technology to achieve the flight of spacecraft into and through outer space.

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.

Adapted from the Wikipedia article Spaceflight, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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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 (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 higher delta-v.

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

Adapted from the Wikipedia article Orbital spaceflight, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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A space-based unit, the characters and toys were released around the time of the second wave of enthusiasm for space travel and exploration at the start of the shuttle orbiter program (in 1981) during the space-friendly Reagan administration and the ”Star Wars” era. The range was small and limited in scope.

Described in promotional material as: “Action Force’s eyes and ears above the Earth’s atmosphere, they are able to issue early warnings of Ironblood’s hostile plans.” the unit was introduced as part of the second generation of Action Force (see ”Action Force – second generation”). In contrast to the First Generation releases and conventional land-based units Z Force and SAS Force, the figures and vehicles had no real-world equivalents or military reference points. Without a practical need for camouflage, the uniforms and equipment of Space Force were coloured in grey, blue and orange with the principal characters dressed in a style typical of late 1970s and early 1980s science fiction television and movies.

Space Force was the only Action Force range (including the enemy Red Shadows) without a member characterised as being from the United Kingdom or Ireland.

The ”Battle Action Force” back-stories that accompanied the release of the figures were, given the outer-space angle, less extensive than were the case for the SAS Force and Z Force ranges for example. The comicbook storylines created a space station environment to enable stories to be written that included the vehicles, characters and equipment

With limited theatres in which to operate and without toy representations of any space-based Red Shadows characters or vehicles other than the Roboskull, the comic stories (see ”Battle Action Force tie in”) were limited, often to cameo roles in stories involving other Action Force units such as ”Operation Spearhead” (a holiday special) and in ”Crossfire!” Like Q Force, Space Force were never written into any storylines involving Cobra or the third generation Action Force characters however, the Moondancer character (pilot of the Triad Fighter) was one of the few Second Generation characters (including Q Force’s Dolphin) whose profile was taken over to the AF (Third Generation) release in an unreconstructed form.

The action figures were, in keeping with much of the second generation of Action Force, repaints and repackages of existing G.I. Joe figures and vehicles as well as some First Generation toys.

Characters

Vehicles, weaponry and armour=

First release

*Cosmic Cruiser

*Satellite Defence

Second release

*Triad FIghter

==External links

*[http://www.actionforce.org/ Action Force Online] Action Force Online

*[http://www.bloodforthebaron.com/Blood/Index.html Blood For The Baron!!!] Battle Action Force comic scans

Category:Fictional soldiers

Category:Action Force characters

Category:G.I. Joe

Category:Fictional military organizations
Adapted from the Wikipedia article Space Force (Action Force), under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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* February 8 – After 84 days in space, the last crew of the temporary American space station Skylab return to Earth

*date unknown* A radio telescope sent the message “Is there anyone out there?” to the consellation Hercules. It will take 25,000 years to arrive.

Adapted from the Wikipedia article 1974 in science, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Cosmology was studied extensively in the Muslim world during what is known as the Islamic Golden Age from the 7th to 15th centuries.

There are exactly seven verses in the Quran that specify that there are seven heavens.

One verse says that each heaven or sky has its own order, possibly meaning laws of nature. Another verse says after mentioning the seven heavens “and similar earths”.

In 850, al-Farghani wrote ”Kitab fi Jawani” (“”A compendium of the science of stars””). The book primarily gave a summary of Ptolemic cosmography. However, it also corrected Ptolemy’s ”Almagest” based on findings of earlier Iranian astronomers. Al-Farghani gave revised values for the obliquity of the ecliptic, the precessional movement of the apogees of the sun and the moon, and the circumference of the earth. The books were widely circulated through the Muslim world, and even translated into Latin.

Cosmography

”ʿAjā’ib al-makhlūqāt wa gharā’ib al-mawjūdāt” (, meaning ”Marvels of creatures and Strange things existing”) is an important work of cosmography by Zakariya ibn Muhammad ibn Mahmud Abu Yahya al-Qazwini who was born in Qazwin year 600 (AH (1203 AD).

Temporal finitism

In contrast to ancient Greek philosophers who believed that the universe had an infinite past with no beginning, medieval philosophers and theologians developed the concept of the universe having a finite past with a beginning (see Temporal finitism). This

:”An actual infinite cannot exist.”

:”An infinite temporal regress of events is an actual infinite.”

:”.•. An infinite temporal regress of events cannot exist.”

The second argument, the “argument from the impossibility of completing an actual infinite by successive addition”, states:

:”An actual infinite cannot be completed by successive addition.”

:”The temporal series of past events has been completed by successive addition.”

:”.•. The temporal series of past events cannot be an actual infinite.”

Both arguments were adopted by later Christian philosophers and theologians, and the second argument in particular became more famous after it was adopted by Immanuel Kant in his thesis of the first antimony concerning time.

Galaxy observation

The Arabian astronomer Alhazen (965–1037) made the first attempt at observing and measuring the Milky Way’s parallax, and he thus “determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere.” The Persian astronomer Abū Rayhān al-Bīrūnī (973–1048) proposed the Milky Way galaxy to be “a collection of countless fragments of the nature of nebulous stars.” The Andalusian astronomer Ibn Bajjah (“Avempace”, d. 1138) proposed that the Milky Way was made up of many stars which almost touched one another and appeared to be a continuous image due to the effect of refraction from sublunary material, citing his observation of the conjunction of Jupiter and Mars on 500 AH (1106/1107 AD) as evidence. Ibn Qayyim Al-Jawziyya (1292–1350) proposed the Milky Way galaxy to be “a myriad of tiny stars packed together in the sphere of the fixed stars”.

In the 10th century, the Persian astronomer Abd al-Rahman al-Sufi (known in the West as ”Azophi”) made the earliest recorded observation of the Andromeda Galaxy, describing it as a “small cloud”. Al-Sufi also identified the Large Magellanic Cloud, which is visible from Yemen, though not from Isfahan; it was not seen by Europeans until Magellan’s voyage in the 16th century. These were the first galaxies other than the Milky Way to be observed from Earth. Al-Sufi published his findings in his ”Book of Fixed Stars” in 964.

Possible worlds

Al-Ghazali, in ”The Incoherence of the Philosophers”, defends the Ash’ari doctrine of a created universe that is temporally finite, against the Aristotelian doctrine of an eternal universe. In doing so, he proposed the modal theory of possible worlds, arguing that their actual world is the best of all possible worlds from among all the alternate timelines and world histories that God could have possibly created. His theory parallels that of Duns Scotus in the 14th century. While it is uncertain whether Al-Ghazali had any influence on Scotus, they both may have derived their theory from their readings of Avicenna’s ”Metaphysics”.

Multiversal cosmology

Fakhr al-Din al-Razi (1149–1209), in dealing with his conception of physics and the physical world in his ”Matalib al-’Aliya”, criticizes the idea of the Earth’s centrality within the universe and “explores the notion of the existence of a multiverse in the context of his commentary” on the Qur’anic verse, “All praise belongs to God, Lord of the Worlds.” He raises the question of whether the term “worlds” in this verse refers to “multiple worlds within this single universe or cosmos, or to many other universes or a multiverse beyond this known universe.” In volume 4 of the ”Matalib”, Al-Razi states:

Al-Razi rejected the Aristotelian and Avicennian notions of a single universe revolving around a single world. He describes their main arguments against the existence of multiple worlds or universes, pointing out their weaknesses and refuting them. This rejection arose from his affirmation of atomism, as advocated by the Ash’ari school of Islamic theology, which entails the existence of vacant space in which the atoms move, combine and separate. He discussed more on the issue of the void in greater detail in volume 5 of the ”Matalib”. He argued that there exists an infinite outer space beyond the known world, and that God has the power to fill the vacuum with an infinite number of universes.

Refutations of astrology

The study of astrology was refuted by several Muslim writers at the time, including al-Farabi, Ibn al-Haytham, Avicenna, Biruni and Averroes. Their reasons for refuting astrology were often due to both scientific (the methods used by astrologers being conjectural rather than empirical) and religious (conflicts with orthodox Islamic scholars) reasons.

Ibn Qayyim Al-Jawziyya (1292–1350), in his ”Miftah Dar al-SaCadah”, used empirical arguments in astronomy in order to refute the practice of astrology and divination. He recognized that the stars are much larger than the planets, and thus argued:

Al-Jawziyya also recognized the Milky Way galaxy as “a myriad of tiny stars packed together in the sphere of the fixed stars” and thus argued that “it is certainly impossible to have knowledge of their influences.”

Early heliocentric models

The Babylonian astronomer, Seleucus of Seleucia, who advocated a heliocentric model in the 2nd century BC, wrote a work that was later translated into Arabic. A fragment of his work has survived only in Arabic translation, which was later referred to by the Persian philosopher Muhammad ibn Zakariya al-Razi (865-925).

In the late ninth century, Ja’far ibn Muhammad Abu Ma’shar al-Balkhi (Albumasar) developed a planetary model which some have interpreted as a heliocentric model. This is due to his orbital revolutions of the planets being given as heliocentric revolutions rather than geocentric revolutions, and the only known planetary theory in which this occurs is in the heliocentric theory. His work on planetary theory has not survived, but his astronomical data was later recorded by al-Hashimi, Abū Rayhān al-Bīrūnī and al-Sijzi.

In the early eleventh century, al-Biruni had met several Indian scholars who believed in a heliocentric system. In his ”Indica”, he discusses the theories on the Earth’s rotation supported by Brahmagupta and other Indian astronomers, while in his ”Canon Masudicus”, al-Biruni writes that Aryabhata’s followers assigned the first movement from east to west to the Earth and a second movement from west to east to the fixed stars. Al-Biruni also wrote that al-Sijzi also believed the Earth was moving and invented an astrolabe called the “Zuraqi” based on this idea:

In his ”Indica”, al-Biruni briefly refers to his work on the refutation of heliocentrism, the ”Key of Astronomy”, which is now lost:

Early ”Hay’a” program

During this period, a distinctive Islamic system of astronomy flourished. It was Greek tradition to separate mathematical astronomy (as typified by Ptolemy) from philosophical cosmology (as typified by Aristotle). Muslim scholars developed a program of seeking a physically real configuration (”hay’a”) of the universe, that would be consistent with both mathematical and physical principles. Within the context of this ”hay’a” tradition, Muslim astronomers began questioning technical details of the Ptolemaic system of astronomy.

Some Muslim astronomers, however, most notably Abū Rayhān al-Bīrūnī and Nasīr al-Dīn al-Tūsī, discussed whether the Earth moved and considered how this might be consistent with astronomical computations and physical systems. Several other Muslim astronomers, most notably those following the Maragha school of astronomy, developed non-Ptolemaic planetary models within a geocentric context that were later adapted by the Copernican model in a heliocentric context.

Between 1025 and 1028, Ibn al-Haytham (Latinized as Alhazen), began the ”hay’a” tradition of Islamic astronomy with his ”Al-Shuku ala Batlamyus” (”Doubts on Ptolemy”). While maintaining the physical reality of the geocentric model, he was the first to criticize Ptolemy’s astronomical system, which he criticized on empirical, observational and experimental grounds, and for relating actual physical motions to imaginary mathematical points, lines and circles. Ibn al-Haytham developed a physical structure of the Ptolemaic system in his ”Treatise on the configuration of the World”, or ”Maqâlah fî ”hay’at” al-‛âlam”, which became an influential work in the ”hay’a” tradition. In his ”Epitome of Astronomy”, he insisted that the heavenly bodies “were accountable to the laws of physics.”

In 1038, Ibn al-Haytham described the first non-Ptolemaic configuration in ”The Model of the Motions”. His reform was not concerned with cosmology, as he developed a systematic study of celestial kinematics that was completely geometric. This in turn led to innovative developments in infinitesimal geometry. His reformed model was the first to reject the equant and eccentrics, separate natural philosophy from astronomy, free celestial kinematics from cosmology, and reduce physical entities to geometrical entities. The model also propounded the Earth’s rotation about its axis, and the centres of motion were geometrical points without any physical significance, like Johannes Kepler’s model centuries later. Ibn al-Haytham also describes an early version of Occam’s razor, where he employs only minimal hypotheses regarding the properties that characterize astronomical motions, as he attempts to eliminate from his planetary model the cosmological hypotheses that cannot be observed from Earth.

In 1030, Abū al-Rayhān al-Bīrūnī discussed the Indian planetary theories of Aryabhata, Brahmagupta and Varahamihira in his ”Ta’rikh al-Hind” (Latinized as ”Indica”). Biruni stated that Brahmagupta and others consider that the earth rotates on its axis and Biruni noted that this does not create any mathematical problems. Abu Said al-Sijzi, a contemporary of al-Biruni, suggested the possible heliocentric movement of the Earth around the Sun, which al-Biruni did not reject. Al-Biruni agreed with the Earth’s rotation about its own axis, and while he was initially neutral regarding the heliocentric and geocentric models, he considered heliocentrism to be a philosophical problem. He remarked that if the Earth rotates on its axis and moves around the Sun, it would remain consistent with his astronomical parameters:

Andalusian Revolt

In the 11th-12th centuries, astronomers in al-Andalus took up the challenge earlier posed by Ibn al-Haytham, namely to develop an alternate non-Ptolemaic configuration that evaded the errors found in the Ptolemaic model. Like Ibn al-Haytham’s critique, the anonymous Andalusian work, ”al-Istidrak ala Batlamyus” (”Recapitulation regarding Ptolemy”), included a list of objections to Ptolemic astronomy. This marked the beginning of the Andalusian school’s revolt against Ptolemaic astronomy, otherwise known as the “Andalusian Revolt”.

In the 12th century, Averroes rejected the eccentric deferents introduced by Ptolemy. He rejected the Ptolemaic model and instead argued for a strictly concentric model of the universe. He wrote the following criticism on the Ptolemaic model of planetary motion:

Averroes’ contemporary, Maimonides, wrote the following on the planetary model proposed by Ibn Bajjah (Avempace):

Ibn Bajjah also proposed the Milky Way galaxy to be made up of many stars but that it appears to be a continuous image due to the effect of refraction in the Earth’s atmosphere. Later in the 12th century, his successors Ibn Tufail and Nur Ed-Din Al Betrugi (Alpetragius) were the first to propose planetary models without any equant, epicycles or eccentrics. Al-Betrugi was also the first to discover that the planets are self-luminous. Their configurations, however, were not accepted due to the numerical predictions of the planetary positions in their models being less accurate than that of the Ptolemaic model, mainly because they followed Aristotle’s notion of perfectly uniform circular motion.

Maragha Revolution

The “Maragha Revolution” refers to the Maragheh school’s revolution against Ptolemaic astronomy. The “Maragha school” was an astronomical tradition beginning in the Maragheh observatory and continuing with astronomers from Damascus and Samarkand. Like their Andalusian predecessors, the Maragha astronomers attempted to solve the equant problem and produce alternative configurations to the Ptolemaic model. They were more successful than their Andalusian predecessors in producing non-Ptolemaic configurations which eliminated the equant and eccentrics, were more accurate than the Ptolemaic model in numerically predicting planetary positions, and were in better agreement with empirical observations. The most important of the Maragha astronomers included Mo’ayyeduddin Urdi (d. 1266), Nasīr al-Dīn al-Tūsī (1201–1274), Najm al-Dīn al-Qazwīnī al-Kātibī (d. 1277), Qutb al-Din al-Shirazi (1236–1311), Sadr al-Sharia al-Bukhari (c. 1347), Ibn al-Shatir (1304–1375), Ali al-Qushji (c. 1474), al-Birjandi (d. 1525) and Shams al-Din al-Khafri (d. 1550).

Some have described their achievements in the 13th and 14th centuries as a “Maragha Revolution”, “Maragha School Revolution”, or “Scientific Revolution before the Renaissance”. An important aspect of this revolution included the realization that astronomy should aim to describe the behavior of physical bodies in mathematical language, and should not remain a mathematical hypothesis, which would only save the phenomena. The Maragha astronomers also realized that the Aristotelian view of motion in the universe being only circular or linear was not true, as the Tusi-couple showed that linear motion could also be produced by applying circular motions only.

Unlike the ancient Greek and Hellenistic astronomers who were not concerned with the coherence between the mathematical and physical principles of a planetary theory, Islamic astronomers insisted on the need to match the mathematics with the real world surrounding them, which gradually evolved from a reality based on Aristotelian physics to one based on an empirical and mathematical physics after the work of Ibn al-Shatir. The Maragha Revolution was thus characterized by a shift away from the philosophical foundations of Aristotelian cosmology and Ptolemaic astronomy and towards a greater emphasis on the empirical observation and mathematization of astronomy and of nature in general, as exemplified in the works of Ibn al-Shatir, al-Qushji, al-Birjandi and al-Khafri.

The work of Ali al-Qushji (d. 1474), who worked at Samarkand and then Istanbul, is seen as a late example of innovation in Islamic theoretical astronomy and it is believed he may have possibly had some influence on Nicolaus Copernicus due to similar arguments concerning the Earth’s rotation. Before al-Qushji, the only astronomer to present empirical evidence for the Earth’s rotation was Nasīr al-Dīn al-Tūsī (d. 1274), who used the phenomena of comets to refute Ptolemy’s claim that a stationary Earth can be determined through observation. Al-Tusi, however, eventually accepted that the Earth was stationary on the basis of Aristotelian cosmology and natural philosophy. By the 15th century, the influence of Aristotelian physics and natural philosophy was declining due to religious opposition from Islamic theologians such as Al-Ghazali who opposed to the interference of Aristotelianism in astronomy, opening up possibilities for an astronomy unrestrained by philosophy. Under this influence, Al-Qushji, in his ”Concerning the Supposed Dependence of Astronomy upon Philosophy”, rejected Aristotelian physics and completely separated natural philosophy from astronomy, allowing astronomy to become a purely empirical and mathematical science. This allowed him to explore alternatives to the Aristotelian notion of a stationary Earth, as he explored the idea of a moving Earth. He also observed comets and elaborated on al-Tusi’s argument. He took it a step further and concluded, on the basis of empirical evidence rather than speculative philosophy, that the moving Earth theory is just as likely to be true as the stationary Earth theory and that it is not possible to empirically deduce which theory is true. His work was an important step away from Aristotelian physics and towards an independent astronomical physics.

Despite the similarity in their discussions regarding the Earth’s motion, there is uncertainty over whether al-Qushji had any influence on Copernicus. However, it is likely that they both may have arrived at similar conclusions due to using the earlier work of al-Tusi as a basis. This is more of a possibility considering “the remarkable coincidence between a passage in ”De revolutionibus” (I.8) and one in Ṭūsī’s ”Tadhkira” (II.1[6]) in which Copernicus follows Ṭūsī’s objection to Ptolemy’s “proofs” of the Earth’s immobility.” This can be considered as evidence that not only was Copernicus influenced by the mathematical models of Islamic astronomers, but may have also been influenced by the astronomical physics they began developing and their views on the Earth’s motion.

In the 16th century, the debate on the Earth’s motion was continued by al-Birjandi (d. 1528), who in his analysis of what might occur if the Earth were moving, develops a hypothesis similar to Galileo Galilei’s notion of “circular inertia”, which he described in the following observational test (as a response to one of Qutb al-Din al-Shirazi’s arguments):

Adapted from the Wikipedia article Islamic cosmology, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Commercial launchers

The space transport business serves primarily national government and large commercial customer segments. Launches of government payloads, including military, civilian and scientific satellites, is the largest market segment at nearly $100 billion a year. This segment is dominated by domestic favorites such as the United Launch Alliance for U.S. government payloads and Arianespace for European satellites. The commercial payload segment, valued at under $3 billion a year, is dominated by Arianespace, with over 50% of the market segment, followed by Russian launchers. See a complete list of launch systems.

Commercial Orbital Transportation Services

On January 18, 2006 NASA announced an opportunity for commercial providers to demonstrate orbital transportation services. NASA plans to spend $500 million through 2010 to finance development of private sector capability to transport payloads to the International Space Station (ISS). This is more challenging than extant commercial space transportation because it requires precision orbit insertion, rendezvous and possibly docking with another spacecraft. The commercial vendors will compete in specific service areas. NASA Administrator Michael D. Griffin has stated that without affordable commercial orbital transportation services (COTS), the agency will not have enough funds remaining to achieve the objectives of the Vision for Space Exploration.

In August 2006, NASA announced that two fledgling aerospace companies, SpaceX and Rocketplane Kistler, had been awarded $278m and $207m, respectively, under the COTS program. NASA anticipates that COTS services to ISS will be necessary through at least 2015. The NASA Administrator has suggested that space transportation services procurement may be expanded to orbital fuel depots and lunar surface deliveries should the first phase of COTS prove successful.

After it transpired that Rocketplane Kistler was failing to meet its deadlines, the NASA terminated their contract in August 2008, after only $32m had been spent. Several months later, in December 2008, NASA announced that they have awarded the remaining $170m to the trusted Orbital Sciences Corporation to develop resupply services to the ISS.

Commercial Space Station

Bigelow Aerospace is developing the ”Next-Generation Commercial Space Station”, a private orbital space complex. The space station will be constructed of both Sundancer and BA 330 expandable spacecraft modules as well as a central docking node, propulsion, solar arrays, and attached crew capsules. , initial launch of space station components is planned for 2014, with portions of the station projected to be available for leased use as early as 2015.

Emerging personal spaceflight

Before 2004 no privately operated manned spaceflight had ever occurred. The only private individuals to journey to space went as space tourists in the Space Shuttle or on Russian Soyuz flights to Mir or the International Space Station.

All private individuals who flew to space before Dennis Tito’s self-financed International Space Station visit in 2001 had been sponsored by their home governments. Those trips include US Congressman Bill Nelson’s January 1986 flight on the Space Shuttle Columbia and Japanese television reporter Toyohiro Akiyama’s 1990 flight to the Mir Space Station.

The Ansari X PRIZE was intended to stimulate private investment in the development of spaceflight technologies. The June 21, 2004 test flight of SpaceShipOne, a contender for the X PRIZE, was the first human spaceflight in a privately developed and operated vehicle.

On September 27, 2004, following the success of SpaceShipOne, Richard Branson, owner of Virgin and Burt Rutan, SpaceShipOne’s designer, announced that Virgin Galactic had licensed the craft’s technology, and were planning commercial space flights in 2.5 to 3 years. A fleet of five craft (SpaceShipTwo, launched from the WhiteKnightTwo carrier airplane) is to be constructed, and flights will be offered at around $200,000 each, although Branson has said he plans to use this money to make flights more affordable in the long term.

XCOR Aerospace also plans to initiate a suborbital commercial spaceflight service with the Lynx rocketplane in 2012. First test flights are planned for 2010.

In December 2004, United States President George W. Bush signed in to law the Commercial Space Launch Amendments Act. The Act resolved the regulatory ambiguity surrounding private spaceflights and is designed to promote the development of the emerging U.S. commercial human space flight industry.

On July 12, 2006, Bigelow Aerospace launched the ”Genesis I”, a subscale pathfinder of an orbital space station module. ”Genesis II” was launched on June 28, 2007, and there are plans for additional prototypes to be launched in preparation for the production model ”BA 330” spacecraft.

On September 28, 2006, Jim Benson, SpaceDev founder, announced he was founding Benson Space Company with the intention of being first to market with the safest and lowest cost suborbital personal spaceflight launches, using the vertical takeoff and horizontal landing Dream Chaser vehicle based on the NASA HL-20 Personnel Launch System vehicle.

Adapted from the Wikipedia article Private spaceflight, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. Earth is the only known inhabited planet in the universe to date. However, advancements in the fields of astrobiology, observational astronomy and discovery of large varieties of extremophiles with extraordinary capability to thrive in harshest environments on Earth, have led to speculation that life may possibly be thriving on many of the extraterrestrial bodies in the universe. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry, laboratory and field research into the origins and early evolution of life on Earth, and studies of the potential for life to adapt to challenges on Earth and in outer space.

Astrobiology makes use of physics, chemistry, astronomy, biology, Abiogenesis, molecular biology, ecology, planetary science, geography and geology to investigate the possibility of life on other worlds and help recognize biospheres that might be different from the Earth’s. Astrobiology concerns itself with an interpretation of existing scientific data; given more detailed and reliable data from other parts of the Universe, the roots of astrobiology itself—physics, chemistry, and biology—may have their theoretical bases challenged. Although speculation is entertained to give context, astrobiology concerns itself primarily with hypotheses that fit firmly into existing scientific theories.

Adapted from the Wikipedia article Astrobiology, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Space race

After the Soviet space program’s launch of the world’s first artificial satellite (”Sputnik 1”) on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts. The U.S. Congress, alarmed by the perceived threat to national security and technological leadership (known as the “Sputnik crisis”), urged immediate and swift action; President Dwight D. Eisenhower and his advisers counseled more deliberate measures. Several months of debate produced an agreement that a new federal agency was needed to conduct all non-military activity in space. The Advanced Research Projects Agency (ARPA) was also created at this time to develop space technology for military application.

NACA

From late 1957 to early 1958, the National Advisory Committee for Aeronautics (NACA) began studying what a new non-military space agency would entail, as well as what its role might be, and assigned several committees to review the concept. On January 12, 1958, NACA organized a “Special Committee on Space Technology”, headed by Guyford Stever. Stever’s committee included consultation from the Army Ballistic Missile Agency’s large booster program, referred to as the Working Group on Vehicular Program, headed by Wernher von Braun, a German scientist who became a naturalized US citizen after World War II.

On January 14, 1958, NACA Director Hugh Dryden published “A National Research Program for Space Technology” stating:

Launched on January 31, 1958, Explorer 1, officially Satellite 1958 Alpha, became the U.S.’s first earth satellite. The Explorer 1 payload consisted of the Iowa Cosmic Ray Instrument without a tape data recorder which was not modified in time to make it onto the satellite.

On March 5, PSAC Chairman James Killian wrote a memorandum to President Eisenhower, entitled “Organization for Civil Space Programs”, encouraging the creation of a civil space program based upon a “strengthened and redesignated” NACA which could expand its research program “with a minimum of delay.” In late March, a NACA report entitled “Suggestions for a Space Program” included recommendations for subsequently developing a hydrogen fluorine fueled rocket of thrust designed with second and third stages.

In April 1958, Eisenhower delivered to the U.S. Congress an executive address favoring a national civilian space agency and submitted a bill to create a “National Aeronautical and Space Agency.” NACA’s former role of research alone would change to include large-scale development, management, and operations. The U.S. Congress passed the bill, somewhat reworded, as the National Aeronautics and Space Act of 1958, on July 16. Only two days later von Braun’s Working Group submitted a preliminary report severely criticizing the duplication of efforts and lack of coordination among various organizations assigned to the United States’ space programs. Stever’s Committee on Space Technology concurred with the criticisms of the von Braun Group (a final draft was published several months later, in October).

NASA

Apollo set major milestones in human spaceflight. It stands alone in sending manned missions beyond low Earth orbit, and landing humans on another celestial body. Apollo 8 was the first manned spacecraft to orbit another celestial body, while Apollo 17 marked the last moonwalk and the last manned mission beyond low Earth orbit. The program spurred advances in many areas of technology peripheral to rocketry and manned spaceflight, including avionics, telecommunications, and computers. Apollo sparked interest in many fields of engineering and left many physical facilities and machines developed for the program as landmarks. Many objects and artifacts from the program are on display at various locations throughout the world, notably at the Smithsonian’s Air and Space Museums.

International Space Station

The International Space Station (ISS) is an internationally developed research facility currently being assembled in Low Earth Orbit. On-orbit construction of the station began in 1998 and is scheduled to be completed by 2011, with operations continuing until at least 2015. The station can be seen from the Earth with the naked eye, and, , is the largest artificial satellite in Earth orbit, with a mass larger than that of any previous space station.

The ISS is operated as a joint project among NASA, the Russian Federal Space Agency, the Japan Aerospace Exploration Agency, the Canadian Space Agency, and the European Space Agency (ESA). Ownership and utilization of the space station is set out via several intergovernmental treaties and agreements, with the Russian Federation retaining full ownership of its own modules, and the rest of the station being allocated among the other international partners. The International Space Station relied on the Shuttle fleet for all major construction shipments.

The cost of the station project has been estimated by ESA as €100 billion over a course of 30 years, although cost estimates vary between 35 billion dollars and 160 billion dollars, making the ISS the most expensive object ever constructed.

Unmanned programs

Mariner program

The Mariner program conducted by NASA launched a series of robotic interplanetary probes designed to investigate Mars, Venus and Mercury. The program included a number of firsts, including the first planetary flyby, the first pictures from another planet, the first planetary orbiter, and the first gravity assist maneuver.

Of the ten vehicles in the Mariner series, seven were successful and three were lost. The planned Mariner 11 and Mariner 12 vehicles evolved into Voyager 1 and Voyager 2 of the Voyager program, while the Viking 1 and Viking 2 Mars orbiters were enlarged versions of the Mariner 9 spacecraft. Other Mariner-based spacecraft, launched since Voyager, included the Magellan probe to Venus, and the Galileo probe to Jupiter. A second-generation Mariner spacecraft, called the Mariner Mark II series, eventually evolved into the Cassini-Huygens probe, now in orbit around Saturn.

All Mariner spacecraft were based on a hexagonal or octagonal “bus”, which housed all of the electronics, and to which all components were attached, such as antennae, cameras, propulsion, and power sources. All probes except Mariner 1, Mariner 2 and Mariner 5 had TV cameras. The first five Mariners were launched on Atlas-Agena rockets, while the last five used the Atlas-Centaur. All Mariner-based probes after Mariner 10 used the Titan IIIE, Titan IV unmanned rockets or the Space Shuttle with a solid-fueled Inertial Upper Stage and multiple planetary flybys.

”Galileo” was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. It was launched on October 18, 1989 by the Space Shuttle ”Atlantis” on the STS-34 mission. It arrived at Jupiter on December 7, 1995, a little more than six years later, via gravitational assist flybys of Venus and Earth.

Despite antenna problems, ”Galileo” conducted the first asteroid flyby, discovered the first asteroid moon, was the first spacecraft to orbit Jupiter, and launched the first probe into Jupiter’s atmosphere. Galileo’s prime mission was a two-year study of the Jovian system. The spacecraft traveled around Jupiter in elongated ellipses, each orbit lasting about two months. The differing distances from Jupiter afforded by these orbits allowed ”Galileo” to sample different parts of the planet’s extensive magnetosphere. The orbits were designed for close up flybys of Jupiter’s largest moons. Once Galileo’s prime mission was concluded, an extended mission followed starting on December 7, 1997; the spacecraft made a number of daring close flybys of Jupiter’s moons Europa and Io. The closest approach was (112& mi) on October 15, 2001.

On September 21, 2003, after 14 years in space and eight years of service in the Jovian system, ”Galileo”′s mission was terminated by sending the orbiter into Jupiter’s atmosphere at a speed of nearly 50 kilometers per second to avoid any chance of it contaminating local moons with bacteria from Earth. Of particular interest was the ice-crusted moon Europa, which, thanks to ”Galileo”, scientists now suspect harbors a salt water ocean beneath its surface.

Mars Pathfinder

The ”Mars Pathfinder” (MESUR Pathfinder), later renamed the ”Carl Sagan Memorial Station”, was launched on December 4, 1996, just a month after the ”Mars Global Surveyor” was launched. Onboard the lander was a small rover called ”Sojourner” that would execute many experiments on the Martian surface. It was the second project from NASA’s Discovery Program, which promotes the use of low-cost spacecraft and frequent launches under the motto “cheaper, faster and better” promoted by the then administrator, Daniel Goldin. The mission was directed by the Jet Propulsion Laboratory, a division of the California Institute of Technology, responsible for NASA’s Mars Exploration Program.

This mission, besides being the first of a series of missions to Mars that included rovers (robotic exploration vehicles), was the most important since the ”Vikings” landed on the red planet in 1976, and also was the first successful mission to send a rover to a planet. In addition to scientific objectives, the Mars Pathfinder mission was also a “proof-of-concept” for various technologies, such as airbag-mediated touchdown and automated obstacle avoidance, both later exploited by the Mars Exploration Rovers. The Mars Pathfinder was also remarkable for its extremely low price relative to other unmanned space missions to Mars.

New Horizons probe

”New Horizons” is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, and Hydra. Once New Horizons leaves the Solar System, NASA may also approve flybys of one or more other Kuiper Belt Objects.

”New Horizons” was launched on January 19, 2006 directly into an Earth-and-solar-escape trajectory. It had an Earth-relative velocity of about /s or /h (10.10& mi/s or 36,373& mi/h) after its last engine shut down. Thus, it left Earth at the fastest launch speed ever recorded for a man-made object (although it’s specific orbital energy is less than that of Voyager 1, and the Helios Probes retain the maximum speed record for a spacecraft). New Horizons flew by Jupiter on February 28, 2007 and Saturn’s orbit on June 8, 2008. It will arrive at Pluto on July 14, 2015 and then continue into the Kuiper belt.

Adapted from the Wikipedia article NASA, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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Space Generation Advisory Council in support of the United Nations Programme on Space Applications is a non-governmental organization which “aims to bring the views of students and young space professionals to the United Nations, Space Agencies and other organisations”.

SGAC’s primary work has been in advancing space policy making, representing the world’s youth on space policy to the United Nations Office for Outer Space Affairs and other international organisations. The SGAC continues to present youth input to the UN through its Observer Status with the United Nations Committee on the Peaceful Uses of Outer Space. SGAC has also been represented at the Space Policy Summit – a meeting of government representatives and heads of space agencies to discuss the future exploration of space. In addition SGAC has contributed to the European Green Paper on Space Policy.

The SGAC was founded in 1999 at a youth forum of the UNISPACE III Conference in Vienna, Austria. Over 160 young people from 60 countries attended the forum, which ran parallel to the UNISPACE III proceedings.

Adapted from the Wikipedia article Space Generation Advisory Council, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki

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