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Mars Direct

Mars Direct

Mars Direct is a proposal for a relatively low-cost manned mission to Mars with current rocket technology. The plan was originally detailed in a research paper by Robert Zubrin and David Baker in 1990. The mission was expanded upon in Zubrin's book 1996 The Case For Mars. The plan is now a staple of Zubrin's speaking engagements and general advocacy as head of the Mars Society and has been released in video format.

The proposal

The plan involves launching an unmanned Earth Return Vehicle (ERV) directly from Earth's surface to Mars using a heavy-lift booster (no bigger than the Saturn V used for the Apollo missions), containing a supply of hydrogen, a chemical plant and a small nuclear reactor. The ERV return vehicle would take some 8 months to reach Mars. Once there, a relatively simple set of chemical reactions (the Sabatier reaction coupled with electrolysis) would combine a small amount of hydrogen carried by the ERV with the carbon dioxide of the Martian atmosphere to create up to 112 tonnes of methane and oxygen propellants, 96 tonnes of which would be needed to return the ERV to Earth at the end of the mission. This process would take approximately 10 months to complete. Some 26 months after the ERV was originally launched from Earth, a second vehicle, the Mars Habitat Unit would be launched on a high-energy transfer to Mars carrying a crew of 4. This vehicle would take some 6 months to reach Mars. During the trip, artificial gravity would be generated by tying the spent upper stage of the booster to the Habitat Unit, and setting them both rotating about a common axis. On reaching Mars, the useless spent upper stage would be jettisoned, with the Habitat Unit aerobraking into Mars orbit before soft-landing in close proximity to the ERV. Once on Mars, the crew would spend 18 months on the surface, carrying out a range of scientific research, aided by a small rover vehicle carried aboard their Habitat Unit, and powered by excess methane produced by the ERV. To return, they use the ERV, leaving the habitat for the possible use of subsequent explorers. The propulsion stage of the ERV would be used as a counterbalance to generate artificial gravity for the trip back. The initial cost estimate for Mars Direct was put at $20 billion, including development costs. In today's terms, this equates to some $30-35 billion. In 2004, NASA and ESA undertook cost modelling exercises to review the cost of human space missions. While the exercise was not an endorsement of Mars Direct, both cost models found Zubrin and Baker's cost estimate to be remarkably accurate.

Revisions

Since Mars Direct was initially conceived, it has undergone considerable review by the Mars Society, NASA and Stanford University. The NASA model, referred to as the Design Reference Mission, currently on version 3, calls for a significant upgrade in hardware (up to 3 launches per mission, not two), and sends the ERV to Mars fully fuelled, parking it in orbit above the planet, where it is reached by a small ascent craft. The Mars Society and Stanford studies retain the original 2-vehicle mission profile of Mars Direct, but increase the crew size to 6. The Mars Society has demonstrated the viability of the Mars Habitat Unit concept through their Mars Analogue Research Station programme.

Mars/Planet

Mars, the fourth planet from the Sun in our solar system, is named after the Roman god of war Mars (Ares in Greek mythology), because of its apparent red color. This feature also earned it the nickname "The Red Planet". Mars has two moons, Phobos and Deimos, which are small and oddly-shaped, possibly being captured asteroids. The prefix areo- refers to Mars in the same way geo- refers to Earth—for example, areology versus geology. (However, areology is also used to refer to the study of Mars as a whole rather than just the geological processes of the planet.) The astronomical symbol for Mars is a circle with an arrow pointing northeast (Unicode: ♂). This symbol is a stylized representation of the shield and spear of the god Mars, and in biology it is used as a sign for the male sex. The Chinese, Korean, Japanese, and Vietnamese cultures refer to the planet as the fire star, 火星, a naming based on the ancient Chinese mythological cycle of Five Elements.

Mythology

Mars has been obvious to skygazers since prehistoric times. It was known by the Egyptians as "Her Deschel" or "the Red One." Among the Babylonians Mars was known as "Nergal" or "the Star of Death." The Romans were the ones to give Mars its modern name, after their god of war.

Physical characteristics

The red, fiery appearance of Mars is caused by iron oxide (rust) on its surface. Mars has only a quarter the surface area of the Earth and only one-tenth the mass, though its surface area is approximately equal to that of the Earth's dry land because Mars lacks oceans. The solar day (or sol) on Mars is very close to Earth's day: 24 hours, 39 minutes, and 35.244 seconds.

Atmosphere

Mars' atmosphere is thin: the air pressure on the surface is only 750 pascals, about 0.75% of the average on Earth. However, the scale height of the atmosphere is about 11 km, somewhat higher than Earth's 6 km. The atmosphere on Mars is 95% carbon dioxide, 3% nitrogen, 1.6% argon, and contains traces of oxygen and water. The atmosphere quite dusty, giving the Martian sky a tawny color when seen from the surface; data from the Mars Exploration Rovers indicates the suspended dust particles are roughly 1.5 microns across. In 2003, methane was apparently discovered in the atmosphere by Earth-based telescopes and possibly confirmed in March 2004 by the Mars Express Orbiter; present measurements state an average methane concentration of about 11±4 ppb by volume (see reference). The thin atmosphere cannot hold heat and is the cause of the lower temperatures on Mars. The maximum temperature is roughly 20℃ (68℉). The presence of methane on Mars would be very intriguing, since as an unstable gas it indicates that there must be (or have been within the last few hundred years) a source of the gas on the planet. Volcanic activity, comet impacts, and the existence of life in the form of microorganisms such as methanogens are among possible but as yet unproven sources. The methane appears to occur in patches, which suggests that it is being rapidly broken down before it has time to become uniformly distributed in the atmosphere, and so it is presumably also continually being released to the atmosphere. Plans are now being made to look for other companion gases that may suggest which sources are most likely; in the Earth's oceans biological methane production tends to be accompanied by ethane, while volcanic methane is accompanied by sulfur dioxide. Other aspects of the Martian atmosphere vary significantly. In the winter months when the poles are in continual darkness, the surface gets so cold that as much as 25% of the entire atmosphere condenses out into meters thick slabs of CO₂ ice (dry ice). When the poles are again exposed to sunlight the CO₂ ice sublimates, creating enormous winds that sweep off the poles as fast as 250 mph. These seasonal actions transport large amounts of dust and water vapor giving rise to Earth-like frost and large cirrus clouds. These clouds of water-ice were photographed by the Opportunity rover in 2004.[http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20041213a/merb_sol290_clouds-B313R1_br.jpg] Recently, evidence has been discovered suggesting that Mars may be warming in the short term[http://news.bbc.co.uk/2/hi/science/nature/4266474.stm]; however, it is now cooler than it was in the 1970s.[http://catdynamics.blogspot.com/2005/09/climate-science-mars-and-politics.html]

Geology

Opportunity The surface of Mars is thought to be primarily composed of basalt, based upon the Martian meteorite collection and orbital observations. There is some evidence that some portion of the Martian surface might be more silica-rich than typical basalt, perhaps similar to andesitic rocks on Earth, though these observations may also be explained by silica glass. Much of the surface is deeply covered by dust as fine as talcum powder. Observations of the magnetic fields on Mars by the Mars Global Surveyor spacecraft have revealed that parts of the planet's crust has been magnetized. This magnetization has been compared to alternating bands found on the ocean floors of Earth. One interesting theory, published in 1999 and reexamined in October 2005 in a publication by the same group, is that these bands could be evidence of the past operation of plate tectonics on Mars. However, this has yet to be proven [http://photojournal.jpl.nasa.gov/catalog/PIA02008] or widely accepted and remains an area of active research. plate tectonics Amongst the findings from the Opportunity rover is the presence of hematite on Mars in the form of small spheres on the Meridiani Planum. The spheres are only a few millimeters in diameter and are believed to have formed as rock deposits under watery conditions billions of years ago. Other minerals have also been found containing forms of sulfur, iron or bromine such as jarosite. This and other evidence led a group of 50 scientists to conclude in the December 9, 2004 edition of the journal Science that "Liquid water was once intermittently present at the Martian surface at Meridiani, and at times it saturated the subsurface. Because liquid water is a key prerequisite for life, we infer conditions at Meridiani may have been habitable for some period of time in Martian history". On the opposite side of the planet the mineral goethite, which (unlike hematite) forms only in the presence of water, along with other evidence of water, has also been found by the Spirit rover in the "Columbia Hills". In 1996, researchers studying a meteorite (ALH84001) believed to have originated from Mars reported features which they attributed to microfossils left by life on Mars. As of 2005, this interpretation remains controversial with no consensus having emerged.
Topography
As of 2005 As of 2005 The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. The surface of Mars as seen from Earth is consequently divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian 'continents' and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major. Syrtis Major Mars has polar ice caps that contain frozen water and carbon dioxide that change with the Martian seasons — the carbon dioxide ice sublimates in summer it uncovers an underlying surface of layered water ice and dust. The polar carbon dioxide "hood" then forms again in winter. The supposedly-extinct shield volcano, Olympus Mons (Mount Olympus), is at 26 km the highest mountain in the solar system. It is in a vast upland region called Tharsis, which contains several large volcanos. See list of mountains on Mars. Mars also has the solar system's largest canyon system, Valles Marineris or the Mariner Valley, which is 4000 km long and 7 km deep. Mars is also scarred by a number of impact craters. The largest of these is the Hellas impact basin, covered with light red sand. See list of craters on Mars. The difference between Mars' highest and lowest points is nearly 31 km (from the top of Olympus Mons at an altitude of 26 km to the bottom of the Hellas impact basin at an altitude of 4 km below the datum). In comparison, the difference between Earth's highest and lowest points (Mount Everest and the Mariana Trench) is only 19.7 km. Combined with the planets' different radii, this means Mars is nearly three times "rougher" than Earth. The International Astronomical Union's Working Group for Planetary System Nomenclature is responsible for naming Martian surface features. Other notes: Zero elevation: Since Mars has no oceans and hence no 'sea level', a zero-elevation surface or mean gravity surface must be selected. The datum for Mars is defined by the fourth-degree and fourth-order spherical harmonic gravity field, with the zero altitude defined by the 610.5 Pa (6.105 mbar) atmospheric pressure surface (approximately 0.6% of Earth's) at a temperature of 273.16 K. This pressure and temperature correspond to the triple point of water. Zero meridian: Mars' equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's, by choice of an arbitrary point which was accepted by later observers. The German astronomers Wilhelm Beer and Johann Heinrich Mädler selected a small circular feature as a reference point when they produced the first systematic chart of Mars features in 1830-32. In 1877, their choice was adopted as the prime meridian by the Italian astronomer Giovanni Schiaparelli when he began work on his notable maps of Mars. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ('Middle Bay' or 'Meridian Bay') along the line of Beer and Mädler, was chosen by Merton Davies of the RAND Corporation to provide a more precise definition of 0.0° longitude when he established a planetographic control point network. RAND Corporation
Canals
Mars has an important place in human imagination due to the belief by some that life existed on Mars. These beliefs are due mainly to observations by many in the 19th century popularized by Percival Lowell and Giovanni Schiaparelli. Schiaparelli called these observed features canali, meaning channels in Italian. This was popularly mistranslated as 'canals', and the myth of the Martian canals began. They were apparently artificial linear features on the surface that were asserted to be canals, and due to seasonal changes in the brightness of some areas that were thought to be caused by vegetation growth. This gave rise to many stories concerning Martians. The linear features are now known to be mostly non-existent or, in some cases, dry ancient watercourses. The color changes have been ascribed to dust storms.
Ice lakes
many stories On 29 July 2005, the BBC reported that a visible ice lake had been discovered in a crater in the north polar region of Mars[http://news.bbc.co.uk/1/hi/sci/tech/4727847.stm]. Images of the crater, taken by the High Resolution Stereo Camera on board the European Space Agency's Mars Express spacecraft, clearly show a broad sheet of ice in the bottom of an unnamed crater located on Vastitas Borealis, a broad plain that covers much of Mars' far northern latitudes, at approximately 70.5° North and 103° East. The crater is 35 km (23 mi) wide and about 2 km (1.2 mi) deep. The BBC report however, appears to have either intentionally sensationalized or unintentionally mis-interpreted the original HRSC/Mars Express feature[http://www.esa.int/SPECIALS/Mars_Express/SEMGKA808BE_0.html], which makes no claim or insinuation that this is a "lake". Like many thousands of other places on Mars, this ice sheet is a thin layer of frost that has condensed onto dark, cold sand dunes (about 200 m high) making their way across the bottom of the crater. The only thing remarkable about this feature is that it is far enough north to maintain at least some frost throughout the year.
The moons of Mars
Mars has two tiny natural moons, Phobos and Deimos, which orbit very close to the planet and are thought to be captured asteroids.
The exploration of Mars
asteroid Dozens of spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, and Japan to study the planet's surface, climate, and geography. Roughly two-thirds of all spacecraft destined for Mars have failed in one manner or another before completing or even beginning their missions. Part of this high failure rate can be ascribed to technical problems, but enough have either failed or lost communications for no apparent reason that some researchers half-jokingly speak of an Earth-Mars "Bermuda Triangle" or of a Great Galactic Ghoul which subsists on a diet of Mars probes, or of a Mars Curse. Among the most successful missions are the Mars probe program, the Mariner and Viking programs, Mars Global Surveyor, Mars Pathfinder, and Mars Odyssey. Global Surveyor has taken pictures of gullies and debris flow features that suggest there may be current sources of liquid water, similar to an aquifer, at or near the surface of the planet. Another possible origin proposed for these gully features is transient melting of surface water snow, frost, or ice. Mars Odyssey determined that there are significant deposits of water ice in the upper meter or so of Mars' regolith within 30° of the north and south pole. In 2003, the ESA launched the Mars Express craft consisting of the Mars Express Orbiter and the lander Beagle 2. Attempts to contact the Beagle 2 failed and it was declared lost in early February 2004. Beagle 2 Also in 2003, NASA launched the twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B). Both missions landed successfully in January 2004 and have met or exceeded all their targets; while a 90-day nominal mission was planned, as of February 2005, their missions have been extended twice and they continue to return science, although some mechanical faults have occurred. Among the most significant science return has been evidence of liquid water some time in the past at both landing sites. In addition, dust devils imaged from ground-level have been detected moving across the surface of Mars by Spirit (MER-A). (See picture below). Dust devils were first imaged on Mars from the surface by Mars Pathfinder. Mars Pathfinder
Nomenclature

Early nomenclature
Although better remembered for mapping the Moon starting in 1830, Johann Heinrich Mädler and Wilhelm Beer were the first "areographers". They started off by establishing once and for all that most of the surface features were permanent, and pinned down Mars' rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars ever made. Rather than giving names to the various markings they mapped, Beer and Mädler simply designated them with letters; Meridian Bay (Sinus Meridiani) was thus feature "a". Over the next twenty years or so, as instruments improved and the number of observers also increased, various Martian features acquired a hodge-podge of names. To give a couple of examples, Solis Lacus was known as the "Oculus" (the Eye), and Syrtis Major was usually known as the "Hourglass Sea" or the "Scorpion". In 1858, it was also dubbed the "Atlantic Canale" by the Jesuit astronomer Angelo Secchi. Secchi commented that it "seems to play the role of the Atlantic which, on Earth, separates the Old Continent from the New" —this was the first time the fateful canale, which in Italian can mean either "channel" or "canal", had been applied to Mars. In 1867, Richard Anthony Proctor drew up a map of Mars based, somewhat crudely, on the Rev. William Rutter Dawes' earlier drawings of 1865, then the best ones available. Proctor explained his system of nomenclature by saying, "I have applied to the different features the names of those observers who have studied the physical peculiarities presented by Mars." Here are some of his names, paired with those later proposed by Schiaparelli:
- Kaiser Sea = Syrtis Major1865
- Lockyer Land = Hellas
- Main Sea = Lacus Moeris
- Herschel II Strait = Sinus Sabaeus
- Dawes Continent = Aeria and Arabia
- De La Rue Ocean = Mare Erythraeum
- Lockyer Sea = Solis Lacus
- Dawes Sea = Tithonius Lacus
- Madler Continent = Chryse, Ophir, Tharsis
- Maraldi Sea = Mares Sirenum and Cimmerium
- Secchi Continent = Memnonia
- Hooke Sea = Mare Tyrrhenum
- Cassini Land = Ausonia
- Herschel I Continent = Zephyria, Aeolis, Aethiopis
- Hind Land = Libya Proctor's nomenclature has often been criticized, mainly because so many of his names honored English astronomers, but also because he used many names more than once. In particular, Dawes appeared no fewer than six times (Dawes Ocean, Dawes Continent, Dawes Sea, Dawes Strait, Dawes Isle, and Dawes Forked Bay). Even so, Proctor's names are not without charm, and for all their shortcomings they were a foundation on which later astronomers would improve.
Modern nomenclature
Today, features on Mars derive from a number of sources. Large albedo features retain many of the older names, but are often updated to reflect new knowledge of the nature of the features. For example 'Nix Olympica' (the snows of Olympus) has become 'Olympus Mons' (Mount Olympus). Large Martian craters are named after important scientists and science fiction writers; smaller ones are named after towns and villages on Earth.
Observation of Mars
Earth passes Mars every 780 days (or two years plus seven weeks and one day) at a distance of about 80,000,000 km. However, this varies because the orbits are elliptical. To a naked-eye observer, Mars usually shows a distinct yellow, orange or reddish colour, and varies in brightness more than any other planet as seen from Earth over the course of its orbit, due to the fact that when furthest away from the Earth it is more than seven times as far from the latter as when it is closest (and can be lost in the Sun's glare for months at a time when least favourably positioned). At its most favourable times — which occur twice every 32 years, alternately at 15 and 17-year intervals, and always between late July and late September — Mars shows a wealth of surface detail to a telescope. Especially noticeable, even at low magnification, are the polar ice caps. polar ice cap On August 27, 2003, at 9:51:13 UT, Mars made its closest approach to Earth in nearly 60,000 years: 55,758,006 km (approximately 35 million miles) without Light-time correction. This close approach came about because Mars was one day from opposition and about three days from its perihelion, making Mars particularly easy to see from Earth. The last time it came so close is estimated to have been on September 12, 57,617 BC. Detailed analysis of the solar system's gravitational landscape forecasts an even closer approach in 2287. However, to keep this in perspective, this record approach was only an imperceptibly tiny fraction less than other recent close approaches that occur four times every 284 years. For instance, the minimum distance on August 22 1924 was 0.37284 AU, compared to 0.37271 AU on August 27 2003, and the minimum distance on August 24 2208 will be 0.37278 AU. A transit of the Earth as seen from Mars will occur on November 10, 2084. At that time the Sun, the Earth and Mars will be exactly in a line. There are also transits of Mercury and transits of Venus, and the moon Deimos is of sufficiently small angular diameter that its partial "eclipses" of the Sun are best considered transits (see Transit of Deimos from Mars). The only occultation of Mars by Venus to be observed was that of October 3, 1590, seen by M. Möstlin at Heidelberg. Heidelberg
Appearance

Martian meteorites
:Main article: Martian meteorites A handful of objects are known that are surely meteorites and may be of Martian origin. Two of them may show signs of ancient bacterial activity. On August 6, 1996 NASA announced that analysis of the ALH 84001 meteorite thought to have come from Mars, shows some features that may be fossils of single-celled organisms, although this idea is controversial. In Solar System Research (March 2004, vol 38, page 97) it was suggested that the unique Kaidun meteorite, recovered from Yemen, may have originated on the Martian moon of Phobos. On April 14, 2004, NASA revealed that a rock known as "Bounce", studied by the Mars Exploration Rover Opportunity, was similar in composition to the meteorite EETA79001-B, discovered in Antarctica in 1979. The rock may have been ejected from the same crater as the meteorite, or from another crater in the same area of the Martian surface.
Life on Mars
Evidence exists that the planet once was significantly more habitable than today, but the question whether living organisms ever actually existed there is an open one. Some researchers think that a certain rock which is believed to have originated on Mars - specifically, meteorite ALH84001 - does contain evidence of past biologic activity, but no consensus about these claims has been achieved so far and recent research indicates that the rock, since its creation several billion years ago, has never been exposed to temperatures for extended periods of time that would allow for liquid water. The Viking probes carried experiments designed to detect microorganisms in Martian soil at their respective landing sites, and had some positive results, later denied by many scientists, resulting in ongoing controversy. Also, present biologic activity is one of the explanations that have been suggested for the presence of traces of methane within the Martian atmosphere, but other explanations not involving life are generally considered more likely. If colonization is going to happen, Mars seems a likely choice due to its rather hospitable conditions (compared with other planets, it is most like Earth).
The Mars flag
colonization In early 2000, a proposed Mars flag flew aboard the space shuttle Discovery. Designed by NASA engineer and Flashline Mars Arctic Research Station task force leader Pascal Lee and carried aboard by astronaut John Mace Grunsfeld, the flag consists of three vertical bars (red, green, and blue), symbolizing the transformation of Mars from a barren planet (red) to one bearing sustainable life (green), and finally to a fully terraformed planet with open bodies of water. This design was suggested by the Kim Stanley Robinson sci-fi trilogy Red Mars, Green Mars, and Blue Mars. While other designs have been proposed, the republican tricolor has been adopted by the Mars Society as its own official banner. In a statement released after the launch of the mission, the Society said that the flag "has now been honored by a vessel of the leading spacefaring nation on Earth," and added that "(i)t is fitting that this action occurred when it did: at the dawning of a new millenium."
Mars in fiction
The depiction of Mars in fiction has been stimulated its dramatic red color and by early scientific speculations that its surface conditions might be capable of supporting life. Until the arrival of planetary probes, the traditional view of Mars derived from the astronomers Percival Lowell and Giovanni Schiaparelli, whose observation of supposedly linear features on the planet created the myth of canals on Mars. For many years, a standard notion of the planet as a drying, cooling, dying world with ancient civilizations constructing irrigation works. Thus originated a large number of science fiction scenarios, the best known of which is H. G. Wells' The War of the Worlds, in which Martians seek to escape their dying planet by invading Earth. After the Mariner and Viking spacecraft had returned pictures of Mars as it really is, an apparently lifeless and canal-less world, these ideas about Mars had to be abandoned and a vogue for accurate, realist depictions of human colonies on Mars developed, the best known of which may be Kim Stanley Robinson's Mars trilogy. However, pseudo-scientific speculations about the Face on Mars and other enigmatic landmarks spotted by space probes have meant that ancient civilizations continue to be a popular theme in science fiction, especially in film. Another popular theme, particularly among American writers, is the Martian colony that fights for independence from Earth. This is a major plot element in the novels of Greg Bear and Kim Stanley Robinson, as well as the movie Total Recall (based on a novel by Philip K. Dick) and the television series Babylon 5. Many video games also use this element, such as Red Faction.
See also

- Areography
- Astrobiology
- Astronomy on Mars
- Colonization of Mars
- Darian calendar
- Face on Mars photo article
- Timekeeping on Mars
- Exploration of Mars
- List of artificial objects on Mars
- List of craters on Mars
- List of mountains on Mars
- Martian meteorite
- Mars photos
- Mars in fiction
- Extraterrestrial life
- Terraforming
- Mars Direct
- Mars in astrology
- Ares
- Tyr
- Richard C. Hoagland
References

- William Sheehan, [http://www.uapress.arizona.edu/onlinebks/mars/contents.htm The Planet Mars: A History of Observation and Discovery], The University of Arizona Press, Tucson, 1996
- Vladimir A. Krasnopolsky, Jean-Pierre Maillard, Tobias C. Owen, [http://www.google.ca/url?sa=U&start=1&q=http://www.cosis.net/abstracts/EGU04/06169/EGU04-A-06169.pdf&e=912 Detection of methane in the Martian atmosphere: evidence for life?], Icarus, 172 (2), 537-547. [http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004Sci...306.1753L&db_key=AST&data_type=HTML&format=&high=439c7b95b425777 Lemmon et al., "Atmospheric Imaging Results from the Mars Exploration Rovers: Spirit and Opportunity"]
External links

- [http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html NASA's Mars fact sheet]
- [http://www.nineplanets.org/mars.html Nine Planets Mars page]
- [http://www.marsnews.com MarsNews.com - News and info site]
- [http://www.student.oulu.fi/~jkorteni/space/mars/surface/ Introduction to Martian topography, with Hubble Space Telescope photos]
- [http://www.geoinf.fu-berlin.de/mex/ FU Berlin: HRSC (camera) experiment at Mars Express] (eng. & ger.; press releases and high resolution images)
- [http://www.giss.nasa.gov/tools/mars24/help/notes.html Technical Notes about Time on Mars]
- [http://history.nasa.gov/SP-4212/on-mars.html On Mars: Exploration of the Red Planet 1958-1978] from the NASA History Office.
- [http://flagspot.net/flags/mars.html The Mars Society flag]
- [http://www.vias.org/spacetrip/mars_globalview.html A Trip Into Space] Photos and descriptions of Mars
- [http://www.cato.org/pubs/wtpapers/980815paper.html Martian Law - a CATO white paper]
- [http://www.marsunearthed.com/ Mars Unearthed] - Comparisons of terrains between Earth and Mars
- [http://www.ibiblio.org//e-notes/VRML/Globe/Globe.htm 3D VRML Mars globe]
- [http://www.enterprisemission.com/ Enterprise Mission: Richard C. Hoagland's Homepage]
Water on Mars

- [http://news.bbc.co.uk/1/hi/sci/tech/4727847.stm Highly visible ice lake found on Mars - BBC]
- Dr. Tony Phillips: [http://science.nasa.gov/headlines/y2000/ast29jun_1m.htm "Making a Splash on Mars"], Science@NASA article, June 29, 2000. Phillips describes the Martian "gullies" and explains the conditions under which liquid water can exist on the surface of Mars.
- [http://news.bbc.co.uk/hi/english/sci/tech/newsid_2009000/2009318.stm BBC News story on subsurface ice deposits on Mars]
- [http://news.bbc.co.uk/1/hi/sci/tech/3426539.stm BBC News update on Mars Express' findings of polar water ice and water-eroded features on the surface]
- [http://www.nasa.gov/vision/universe/solarsystem/opportunity_water.html Mars Rover Scientists Wring Water Story from Rocks] This image taken by Mars Rover Opportunity shows microscopic rock forms indicating past signs of water. Courtesy: NASA
- [http://news.bbc.co.uk/1/hi/sci/tech/4285119.stm BBC News Mars pictures reveal frozen sea]
Mars exploration

- [http://www.transhumanist.com/volume4/space.htm The Political Economy of Very Large Space Projects (Journal Of Evolution and Technology)]
- [http://www.exploremarsnow.org/ exploreMarsnow] Interactive Mars base simulation. Winner of 2003 Webby Award for Science.
- [http://marsrovers.jpl.nasa.gov/home/index.html NASA Mars Exploration Rover Home Page]
- [http://dualmoments.com/marsrovers/index.html Be on Mars] Anaglyphs from the Mars Rovers (3D)
- als:Mars (Planet) ko:화성 ms:Marikh ja:火星 simple:Mars (planet) th:ดาวอังคาร

Earth Return Vehicle

Overview

The Earth Return Vehicle (ERV) forms a part of the Mars Direct humans-to-Mars mission concept first developed by Doctor Robert Zubrin and David Baker in the early 1990s. It is a vehicle designed to return a crew of astronauts from the surface of Mars to Earth at the conclusion of their stay on Mars. It is used in conjunction with the Mars Habitat Unit to enable the human exploration of Mars.

Description

The ERV is a two-stage vehicle, with the upper stage comprising the living accommodation for the crew during their six-month return trip to Earth from Mars. The lower stage of the ERV contains the vehicle’s descent / ascent engines and a small chemical production plant. The ERV is launched atop a heavy lift launch vehicle, possibly derived from the space shuttle. It is unmanned, and only carries sufficient fuel to safely reach the surface of Mars following aerobraking in the planet's atmosphere on its arrival in orbit. Once on the surface of Mars, a small nuclear generator is used to power the chemical production plant carried by the ERV. This in turn uses some six tonnes of hydrogen feedstock aboard the ERV. together with the carbon dioxide of the Martian atmosphere to generate up to 112 tonnes of methane and oxygen, to be used as propellants for the return trip to Earth. These are manufactured through a number of simple chemical reactions (Sabatier reaction; water electrolysis)

Specifications

Round trip payload
Crew compartment	7,100 kg
Reaction control system	400 kg
Biconic brake	2,450 kg
Stage 1(dry)	6,330 kg
Stage 2 (dry)	1,770 kg
Mars-bound payload
Hydrogen for propellant production	5,810 kg
SP-100 Reactor	4,500 kg
Earth-bound payload
Crew	450 kg
Suits	300 kg
Consumables (dry food)	2,000 kg
Soil Samples	150 kg
Stage 1 propulsion system
Usable propellant (methane / oxygen)	70,160 kg
Dry mass	8,850 kg
Total engine thrust	85,237 kgf (835.89 kN
Specific impulse	373 s (3.65 kN·s/kg)
Stage 2 propulsion system
Usable propellant (methane / oxygen)	25,000 kg
Dry mass	2,560 kg
Total engine thrust	9,059 kgf (88.84 kN)
Specific impulse	373 s (3.65 kN·s/kg)

Category:Mars missions

Saturn V

The Saturn V (popularly known as the Moon Rocket) was a multistage liquid-fuel expendable rocket used by NASA's Apollo and Skylab programs. It was the largest production model of the Saturn family of rockets, although NASA contemplated larger models (such as the Nova rocket). The rocket was designed under the direction of Wernher von Braun at the Marshall Space Flight Center, with the lead contractors being The Boeing Company, North American Aviation, Douglas Aircraft Company, and IBM. On all but one of its flights, the Saturn V consisted of three stages — the S-IC first stage, S-II second stage and the S-IVB third stage. All three stages used liquid oxygen (LOX) as an oxidizer. The first stage used RP-1 for fuel, while the second and third stages used liquid hydrogen (LH2). An average mission used the rocket for a total of about 20 minutes. NASA launched thirteen Saturn V rockets from 1967 to 1973, with no loss of payload. (Although Apollo 6 and Apollo 13 did experience engine failures, the onboard computers were able to compensate with extra thrust from the remaining engines.) The main payloads of the rocket were the Apollo spacecraft which carried the NASA astronauts to the Moon. It also launched the Skylab space station, and was supposed to be the prime launch vehicle for the cancelled Voyager program Mars probes, a project later carried out by the Viking program in 1976.

Background

In the early 1960s, the Soviet Union had developed a considerable lead in the Space Race against the United States. In 1957, the Soviets had launched Sputnik 1, the first artificial satellite. And on April 12 1961, Yuri Gagarin had become the first human to travel into space. On May 25, 1961, President Kennedy announced that America would try to land a man on the Moon by the end of the decade. At that time, the only experience the United States had with manned spaceflight was the 15 minute suborbital Freedom 7 flight of Alan Shepard. No rocket in the world could launch a spacecraft to the Moon in one piece. The Saturn I was in development, but had not yet flown, and due to its small size, it would require several launches to place in orbit all the components of a lunar spacecraft. Early in the planning process, NASA considered three leading ideas for the moon mission: Earth Orbit Rendezvous, Direct Ascent, and Lunar Orbit Rendezvous (LOR). Although NASA at first dismissed LOR (considering that rendezvous had yet to be performed in Earth orbit, let alone in lunar orbit) in the end NASA decided that this would be the quickest and easiest method for achieving Kennedy's goal. See Choosing a mission mode for more information. The Marshall Space Flight Center (MSFC) in 1960 through 1962 designed rockets that could be used for various missions, starting with the C-1, which they would later develop into the Saturn I. The C-2 rocket never got very far in the design process before MSFC dropped it in favour of the C-3, using 2 F-1 engines on its first stage, 4 J-2 engines for its second stage, and an S-IV stage, using six RL-10 engines. NASA planned to use this rocket as part of the Earth Orbit Rendezvous concept with at least four or five launches needed for a single mission. However, MSFC was planning an even bigger rocket, the C-4. This would use the S-IVB, a stage with a single J-2 engine. The first stage of the C-4 would also use four F-1 engines. The second stage would be an enlarged version of the second stage of the C-3. This rocket would need only two launches to carry out an Earth Orbit Rendezvous mission. On January 10, 1962, NASA announced plans to build the C-5. This would have five F-1 engines on its first stage, five J-2 engines on its second stage and an S-IVB third stage. The first four flights would be tests, successively testing the three stages, with the last test flight an unmanned circumlunar mission. The first manned flight would not be until 1969 (though, in the end, the first manned flight occurred in December 1968). In the middle of 1962, NASA decided to use an all-up testing scheme, with all three stages tested at once on the very first launch. This would shorten the testing and development timeline, but mean that all the stages would have to work perfectly. It would also reduce the required number of rockets from 25 to 15. In 1963, the C-5 was renamed Saturn V. Also in 1963, Rocketdyne produced the first engines. In 1966, the F-1 passed NASA's first article configuration inspection with complete qualification for manned missions coming on September 6. After intensive design and testing of several years, the rocket was first launched on November 9, 1967 with the Apollo 4 unmanned spacecraft on board.

Technology

The Saturn V is arguably one of the most impressive machines in human history. Over 110 m high and 10 m in diameter, with a total mass of three thousand metric tons and a payload capacity of 118,000 kg to LEO, the Saturn V dwarfed and overpowered all other previous rockets which had successfully flown. It gives a good idea of the scale of Saturn V to note that, at 364 feet, it is just one foot shorter than St Paul's Cathedral in London. Saturn V was designed by the Marshall Space Flight Center in Huntsville, Alabama. It used the new powerful F-1 and J-2 rocket engines for propulsion. Designers decided early on to attempt to use as much technology from the Saturn I program as possible. As such, the S-IVB third stage of the Saturn V was based on the S-IV second stage of the Saturn I. The instrument unit that controlled the Saturn V shared characteristics with that carried by the Saturn I.

Stages

S-IV Saturn V consisted of three separate stages and the instrument unit, which were developed by various contractors of NASA. Interestingly all three stage contractors are now owned by Boeing through mergers and takeovers. All three stages also used small solid-fuelled ullage motors that helped to separate the stages during the launch, and to ensure that the liquid propellants were in a proper position to be drawn into the pumps. In the event of an abort requiring the destruction of the rocket, the range safety officer would send the signal for shaped explosive charges attached to the outer surfaces of the rocket to detonate. These would make cuts in fuel and oxidizer tanks to disperse the fuel quickly and to minimise mixing. After the Launch Escape Tower had been jettisoned the charges were made safe.

S-IC first stage

Launch Escape Tower on February 1, 1968]] The S-IC was built by The Boeing Company at the Michoud Assembly Facility, New Orleans, where the Space Shuttle External Tanks are now constructed. As with almost every rocket stage, most of its mass of over two thousand metric tonnes at launch was fuel, in this case RP-1 rocket fuel and liquid oxygen oxidizer. It was 42 meters tall and 10 meters in diameter, and provided 33.4 MN of thrust to get the rocket through the first 61 kilometers of ascent. The five F-1 engines were arranged in a cross pattern. The center engine was fixed, while the four on the outer ring could be hydraulically turned to control the rocket.

S-II second stage

The S-II was built by North American Aviation at Seal Beach, California. Using liquid hydrogen and liquid oxygen, it had five J-2 engines in a similar arrangement to the S-IC. The second stage accelerated the Saturn V through the upper atmosphere with 5 MN of thrust. When loaded with propellant, 97% of the weight of the stage was propellant. Instead of having an intertank structure to separate the two fuel tanks as was done in the S-IC, the S-II used a common bulkhead that was constructed from both the top of the LOX tank and bottom of the LH2 tank. It consisted of two aluminium sheets separated by a honeycomb structure made of phenol. This had to insulate against the 70 °C temperature difference between the two tanks. The use of a common bulkhead saved 3.6 tonnes in weight. phenol

S-IVB third stage

The S-IVB was built by the Douglas Aircraft Company at Huntington Beach, California. It had one J-2 engine and used the same fuel as the S-II. This stage was used twice during the mission: first for the orbit insertion after second stage cutoff, and later for the trans lunar injection (TLI) burn. The S-IVB also used a common bulkhead to insulate the two tanks. The S-IVB was the only rocket stage of the Saturn V small enough to be transported by plane, in this case the Super Guppy. Apart from the interstage adapter, this stage is nearly identical to the second stage of the Saturn IB rocket.

Instrument unit

The Saturn V Instrument Unit was built by IBM and rode atop the third stage. It was constructed at the Space Systems Center in Huntsville. This computer controlled the operations of the rocket from just before liftoff until the S-IVB was discarded. It included guidance and telemetry systems for the rocket. By measuring the acceleration and vehicle attitude, it could calculate the position and velocity of the rocket and correct for any deviations.

Comparisons

telemetry.]] The Soviet counterpart of the Saturn V was the N1 rocket. It was even bigger than the Saturn V, but never even made it to first stage separation successfully. The decision to use five very powerful engines for the first stage of Saturn V resulted in a much more reliable configuration than the 30 smaller engines of the N-1. During two launches, Apollo 6 and Apollo 13, the Saturn V was even able to recover from the loss of engines. The three-stage Saturn V had a peak thrust of 33.4 MN and a lift capacity of 118,000 kg to LEO. A few newer rockets have been able to challenge the records set by Saturn V:
- The Soviet Energia was even more powerful than the Saturn V, delivering 46 MN of thrust and able to deliver up to 175 metric tonnes to LEO in the "Vulkan" configuration. It never flew at this capacity, and it was only launched twice (both times successfully).
- The Space Shuttle generates a peak thrust of 34.8 MN, although payload capacity to LEO (excl. Shuttle Orbiter itself) is only 28,800 kg. The European Ariane 5 with the newest versions Ariane 5 ECA delivers up to 12,000 kg to geostationary transfer orbit (GTO). The US Delta 4 Heavy, which launched a dummy satellite on December 21, 2004, has a capacity of 13,100 kg to geosynchronous transfer orbit. The Atlas V rocket (using engines based on a Russian design) delivers up to 25,000 kg to LEO and 13,605 kg to GTO.

Assembly

Atlas V rocketAfter the construction of a stage was completed, it was shipped to the Kennedy Space Center. The first two stages were so large that the only way to transport them was by barge. The S-IC constructed in New Orleans was transported down the Mississippi River to the Gulf of Mexico. After rounding Florida, it was then transported up the Banana River to the Vertical Assembly Building (now called the Vehicle Assembly Building). The S-II was constructed in California and so travelled via the Panama Canal. The third stage and Instrument Unit could be carried by the Aero Spacelines Pregnant Guppy and Super Guppy. On arrival at Vertical Assembly Building, each stage was checked out in a horizontal position before being moved to a vertical position. NASA also constructed large spool shaped structures that could be used in place of stages if a particular stage was late. These spools had the same height and mass and contained the same electrical connections as the actual stages. NASA decided to use a mobile launch tower, or "crawler", built by Marion Power Shovel of Ohio. This meant that the rocket was constructed on the launch pad in the VAB and then the whole structure was moved out to the launch site by the crawler, which is still used today by the Space Shuttle program. It runs on four double tracked treads, with each 'shoe' weighing 900 kg. This transporter had to keep the rocket level as it travelled the 3 miles (5 km) to the launch site.

Lunar mission launch sequence

The Saturn V carried the Apollo astronauts to the Moon. All Saturn V missions launched from Launch Complex 39 at the John F. Kennedy Space Center. After the rocket cleared the launch tower, mission control transferred to the Johnson Space Center in Houston, Texas.

S-IC sequence

The first stage burned for 2.5 minutes, lifting the rocket to an altitude of 61 kilometers and a speed of 8600 km/h and burning 2,000,000 kg of propellant. Houston, Texas Saturn V encountered Maximum Dynamic Pressure (Max Q) at about 1 minute 20 seconds into the flight (altitude 12.5 km, 4 km downrange, velocity 1,600 km/h).]] At 8.9 seconds before launch, the first stage ignition sequence started. The center engine ignited first, followed by opposing outboard pairs at 300-millisecond stagger times to reduce the structural loads on the rocket. The moment that full thrust had been confirmed by the onboard computers, the rocket was 'soft-released' in two stages: first, the hold-down arms released the rocket, and second, as the rocket began to accelerate upwards, it was held back somewhat by tapered metal pins being pulled through holes. The latter lasted for half a second. Once the rocket had lifted off, it could not safely settle back down onto the pad if the engines failed. It took about 6 seconds for the rocket to clear the tower. As it moved past the tower, the rocket yawed away to ensure adequate clearance, in case of adverse winds or engine failures. At an altitude of 130 meters (430 feet) the rocket began to roll and then pitch to the correct azimuth. From launch until 38 seconds after second stage ignition, the Saturn V would fly a preprogrammed pitch program biased for the prevailing winds during the launch month. The four outboard engines also tilted away from the center, so that if one engine had shut down early, the thrust of the remaining engines would have been towards the rocket's center of gravity. The Saturn V quickly accelerated, reaching 500 m/s at 2 km in altitude. Much of the early portion of the flight was spent gaining altitude, with the required velocity coming later. At about 80 seconds, the rocket reached the point of the flight with the maximum dynamic pressure ("Max Q"). The dynamic pressure on a rocket is proportional to the air pressure around the rocket and the square of the speed. Although the speed is increasing, the air pressure is decreasing as the rocket gets higher. At 135.5 seconds, the center engine shut down to reduce the acceleration loads on the rocket, since it became lighter as fuel was used. The F-1 engine was not throttlable so this was the easiest method. The crew also experienced their greatest acceleration, 4 g (39 m/s²), just before first stage cut off. The other engines continued to burn until either the oxidizer or fuel was depleted as measured by sensors in the suction assemblies. 600 milliseconds after the engine cutoff, the first stage separated with the help of the eight solid-retrorockets. This occurred at an altitude of about 62 km. The first stage continued to an altitude of 110 km, then fell in the Atlantic Ocean about 560 km from the launch pad.

S-II sequence

Atlantic Ocean After the S-IC sequence, the S-II second stage burned for 6 minutes and propelled the craft to 185 km and 24,600 km/h, bringing it close to orbital velocity. The second stage had a two-part ignition process. In the first part, eight solid-fuel ullage motors ignited for four seconds to give positive acceleration, followed by the five J-2 engines. In the second part, about 30 seconds after the first stage separated, the aft interstage separated from the second stage. This was a precisely controlled maneuver as the interstage could not be allowed to touch the engines and had a clearance of only one meter. At the same time as the interstage separated, the Launch Escape System was jettisoned. See Apollo abort modes for more information about the various abort modes that could have been used during a launch. About 38 seconds after the second stage ignition, the control guidance of the Saturn V switched from a preprogrammed pitch routine to Iterative Guidance Mode, controlled by the Instrument Unit, based on accelerometers and altitude sensors. If the Instrument Unit took the rocket outside allowed limits the crew could either abort or take control of the rocket using one of the rotational hand controllers in the capsule. About 90 seconds before the second stage cutoff, the center engine shut down to reduce longitudinal pogo oscillations. A pogo suppressor, first flown on Apollo 14, stopped this pogo motion but the center engine was still shutdown early. At around this time, the LOX flow rate decreased, changing the mix ratio of the two propellants, ensuring that there would be as little propellant as possible left in the tanks at the end of second stage flight. This was done at a predetermined delta-v. There were five sensors in the bottom of each tank of the S-II. When two of these were uncovered, the Instrument Unit would initiate the staging sequence. One second after the second stage cut off it separated and a tenth of a second later the third stage ignited. The S-II impacted about 4200 km from the launch site.

S-IVB sequence

The third stage burned for a further 2.5 minutes, about 12 minutes after launch. The third stage remained attached while the spacecraft orbited the Earth two and a half times in a 'parking orbit' while astronauts examined the spacecraft and rocket to make sure everything functioned nominally. Unlike with the previous separation, there was no two-stage separation. The interstage between the second and third stages remained attached to the second stage (although it was constructed as part of the third stage). By 10 minutes 30 seconds into the launch, the Saturn V was 164 km in altitude and 1700 km downrange from the launch site. After about 5 more minutes of burning, the rocket cut off. The spacecraft was now in an orbit of about 1800 km by 165 km. This is quite low by Earth orbit standards and would not have remained stable for very long due to interaction between the spacecraft and the Earth's atmosphere. For the two Earth orbit missions of the Saturn V, Apollo 9 and Skylab, the orbit would have been higher. The next two and a half orbits were spent checking out the systems of the spacecraft and preparing the spacecraft for Trans Lunar Injection (TLI). Trans Lunar Injection TLI came about 2 and a half hours after launch, when the third stage reignited to propel the spacecraft to the Moon. The S-IVB burned for almost 6 minutes so that the total spacecraft velocity at cutoff was over 10 km/s, escape velocity. A couple of hours after TLI the Apollo Command Service Module (CSM) separated from the third stage, turned 180 degrees, and docked with the Lunar Module (LM) which rode below the CSM during launch. The CSM and LM then separated from the third stage. If it were to remain on the same trajectory as the spacecraft, the booster could have presented a hazard later in the mission, so the remaining propellant in its tanks was vented out of the engine, changing its trajectory. For third stages from Apollo 13 onwards, controllers directed it to impact the Moon. Seismometers left behind by previous missions detected the impacts, and the information helped map the inside of the Moon. Before that, the stages (except Apollo 9 and Apollo 12) were directed towards a flyby of the Moon that sent them into a solar orbit. Apollo 9s S-IVB was put directly into a solar orbit. Apollo 12s S-IVB stage, on the other hand, had a different fate. On September 3, 2002, Bill Yeung discovered a suspected asteroid which he gave the temporary designation J002E3. It appeared to be in orbit around the Earth, and was soon discovered from spectral analysis to be covered in white titanium dioxide paint, the same paint used for the Saturn V. Although the third stages from Apollo 8, 9, 10, 11 and 12 all went into solar orbits, it was decided that the most plausible explanation was that it was the S-IVB stage from Apollo 12. Mission controllers had planned to send it into orbit around the Sun after a flyby of the Moon but the burn after separating from the Apollo spacecraft lasted too long putting it into a barely-stable orbit around the Earth and Moon. In 1971 through a series of gravitational perturbations it is thought to have entered in a solar orbit and then returned to orbit the Earth 31 years later. It left Earth orbit in June 2003.
Later use of Saturn V systems
2003 in place of the third stage.]] The only launch of the Saturn V not related to the Apollo program was the launch of the Skylab space station. In 1968, the Apollo Applications Program was created to look into science missions that could be performed with the surplus Apollo hardware. Much of the planning centered on the idea of a space station. Originally it was planned to use the 'wet workshop' concept where a rocket stage was launched into orbit and then outfitted in space. This idea was abandoned for the 'dry workshop' concept where a S-IVB stage was converted into a space station on the ground and launched on a Saturn V. In this case of Skylab itself, this S-IVB came from a Saturn IB, with a backup constructed from a Saturn V third stage. This backup is now on display at the National Air and Space Museum. Three crews lived aboard Skylab from May 25, 1973 to February 8, 1974, with Skylab lasting in orbit until May 1979. It was hoped that Skylab would stay in orbit long enough to be visited by the Space Shuttle during its first few flights. This could have raised the orbit and been used as a base for future space stations. However the Shuttle didn't fly until 1981 and it is now realised that Skylab would have been of little use as it was not designed to be refurbished and replenished with supplies. The Space Shuttle was initially conceived of as a cargo transport to be used in concert with the Saturn V. The Shuttle would handle space station logistics, while Saturn V would launch components. Lack of funding for a second Saturn V production run killed this plan and has left the United States without a heavy-lift booster. Some in the U.S. space community have come to lament this situation, as continued production would have allowed the International Space Station to have been lifted with just a handful of launches. Wernher von Braun and others also had plans for a rocket that would have featured eight F-1 engines in its first stage allowing it to launch a manned spacecraft on a direct ascent flight to the Moon. Other plans for the Saturn V called for using a Centaur as an upper stage or adding strap-on boosters. These enhancements would have increased its ability to send large unmanned spacecraft to the outer planets or manned spacecraft to Mars. The second production run of Saturn Vs (had it happened) would very likely have used the F-1A engine in its first stage, providing a substantial performance boost over the first run. Other likely changes would have been the removal of the fins, since they turned out to provide little benefit when compared to their weight; a stretched S-IC first stage to support the more powerful F-1As; and uprated J-2s for the upper stages. Saturn V was also to be the launch vehicle for the nuclear rocket stage RIFT test program and the later NERVA. U.S. proposals for a rocket larger than the Saturn V from the late 1950s through the early 1980s were generally called Nova. Over thirty different large rocket proposals carried the Nova name. As of 2005, NASA has plans to build a heavy-lift, Saturn V-class Shuttle Derived Launch Vehicle using two five-segment versions of the Space Shuttle solid rocket booster (SRB) clustered togeter with either five Space Shuttle Main Engines (SSME) or three RS-68 rocket engines currently in use on the Delta IV rocket. This will use current technology, as the SSME engines are more efficient than the F-1 or J-2 engines, and allow NASA to return to the Moon by 2020. The only Saturn-derived engine, the J-2, will be used on the new vehicle as the J-2S, which may be used on the manned Crew Exploration Vehicle launcher in place of a single SSME, and on the upper stage (known as the "Earth Escape Stage") on the SDLV Heavy Boooster.
Cost
From 1964 until 1973, a total of $US6.5 billion was appropriated for the Saturn V, with the maximum being in 1966 with $US1.2 billion. [http://history.nasa.gov/SP-4029/Apollo_18-16_Apollo_Program_Budget_Appropriations.htm] One of the main reasons for the cancellation of the Apollo program was the cost. In 1966, NASA received its highest budget of $US4.5 billion, about 0.5% of the GDP of the United States at that time. In the same year, the Department of Defense received $63.5 billion. [http://www.house.gov/hasc/about/DODDbudgetauth.html]
Saturn V vehicles and launches
Department of Defense Currently there are three Saturn Vs on display, all displayed horizontally:
- At the Johnson Space Center made up of first stage of SA-514, the second stage from SA-515 and the third stage from SA-513.
- At the Kennedy Space Center made up of S-IC-T (test stage) and the second and third stages from SA-514.
- At the U.S. Space & Rocket Center, Huntsville, Alabama made up of S-IC-D, S-II-F/D and S-IVB-D (all test stages not meant for actual flight). Of these three, only the one at the Johnson Space Center consists only of stages that were meant to be launched. The US Space & Rocket Center also has on display an erect full scale model of the Saturn V. The first stage from SA-515 resides at the Michoud Assembly Facility, New Orleans, Louisiana and the third stage was converted for use as backup Skylab and is now on display at the National Air and Space Museum. A popular, [http://www.space.com/news/spacehistory/saturn_five_000313.html untrue] urban legend, started in 1996, states that NASA has lost or destroyed the blueprints or other plans for the Saturn V. In fact, the plans still exist on microfilm at the Marshall Space Flight Center.
Media

External links

NASA sites

- [http://www.hq.nasa.gov/alsj/ Apollo Lunar Surface Journal]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710065502_1971065502.pdf Saturn launch vehicles (PDF)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700076250_1970076250.pdf Launch complex 39 facility description (PDF)]
Non-NASA sites

- [http://www.apollosaturn.com Apollo Saturn Reference Page]
- [http://www.apolloarchive.com Project Apollo Archive]
- [http://www.geocities.com/launchreport/satstg5.html Space Vehicle History]
Simulators

- [http://www.SaturnVExplorer.com 3D Saturn V Explorer and Launch Simulation Program]
- [http://sourceforge.net/projects/nassp/ Saturn V/Saturn IB simulation for Orbiter spaceflight sim]
References

- Bilstein, Roger E. (1980). Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. NASA SP-4206. ISBN 0-16-048909-1.
- Available for reading on-line: [http://history.nasa.gov/SP-4206/sp4206.htm HTML] or [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970009949_1997011911.pdf PDF]
- and in softcover through the U.S. Government Printing Office: http://history.nasa.gov/gpo/order.html (also published by University Press of Florida, 2003 ISBN 0813026911)
- Saturn illustrated chronology: Saturn's first eleven years, April 1957 - April 1968. [http://history.nasa.gov/MHR-5/contents.htm HTML] or [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740004382_1974004382.pdf PDF]
- Moonport: A history of Apollo launch facilities and operations. [http://www.hq.nasa.gov/office/pao/History/SP-4204/cover.html HTML] or [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790003956_1979003956.pdf PDF] (published by University Press of Florida in two volumes: Gateway to the Moon: Building the Kennedy Space Center Launch Complex, 2001, ISBN 0813020913 and Moon Launch!: A History of the Saturn-Apollo Launch Operations, 2001 ISBN 0813020948
- Apollo By The Numbers: A Statistical Reference. [http://history.nasa.gov/SP-4029/Apollo_00_Welcome.htm HTML] or [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20010008244_2001006037.pdf PDF] (published by Government Reprints Press, 2001, ISBN 1931641005)
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900066482_1990066482.pdf Saturn 5 launch vehicle flight evaluation report: AS-501 Apollo 4 mission (PDF format)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900066486_1990066486.pdf Saturn 5 launch vehicle flight evaluation report: AS-508 Apollo 13 mission (PDF format)]
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750063889_1975063889.pdf Saturn V Flight Manual - SA-503 (PDF format)]
- [http://history.msfc.nasa.gov/saturn_apollo/saturnv_press_kit.html Saturn V Press Kit]
- [http://myweb.accessus.net/~090/as13.html Excerpts from the Apollo 13 Transcript]
- Lawrie, Alan, Saturn, Collectors Guide Publishing, 2005, ISBN 1894959191
- DVDs The Mighty Saturns: Saturn V and The Mighty Saturns: The Saturn I and IB produced by Spacecraft Films [http://www.spacecraftfilms.com/index.html] Category:Space launch vehicles Category:Apollo program

Project Apollo

:For other meanings, see Apollo (disambiguation). Apollo (disambiguation) Project Apollo was a series of human spaceflight missions undertaken by the United States of America using the Apollo spacecraft and Saturn launch vehicle, conducted during the years 1961–1972. It was devoted to the goal of landing a man on the Moon and returning him safely to Earth within the decade of the 1960s. This goal was achieved with the Apollo 11 mission in July 1969. The program continued into the early 1970s to carry out the initial hands-on scientific exploration of the Moon, with a total of six successful landings. As of 2005, there has not been any further human spaceflight beyond low earth orbit. The later Skylab program and the joint American-Soviet Apollo-Soyuz Test Project used equipment originally produced for Apollo, and are often considered to be part of the overall program. The name Apollo, like earlier manned space-flight programs, was named after a god from classical civilizations, and comes from one of the Greek gods.

Background

The Apollo Program was originally conceived late in the Eisenhower administration as a follow-on to the Mercury program, doing advanced manned earth-orbital missions. In fact, it became the third program, following Gemini. The Apollo Program was dramatically reoriented to an aggressive lunar landing goal by President Kennedy with his announcement at a special joint session of Congress on May 25, 1961: :"...I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important in the long-range exploration of space; and none will be so difficult or expensive to accomplish..." (Excerpt from "Special Message to the Congress on Urgent National Needs" [http://www.jfklibrary.org/j052561.htm])

Choosing a mission mode

Having settled upon the Moon as a target, the Apollo mission planners were faced with the challenge of designing a set of flights that would meet Kennedy's stated goal while minimizing risk to human life, cost and demands on technology and astronaut skill. Three possible plans were considered. 1961
- Direct ascent: This plan was to boost a spaceship directly to the moon. The entire spacecraft would land on and return from the moon. This would have required a Nova rocket far more powerful than any in existence at the time.
- Earth orbit rendezvous: This plan, known as Earth orbit rendezvous (EOR), would have required the launch of two Saturn V rockets, one containing the space ship and one containing fuel. The spaceship would have docked in earth orbit and be fueled with enough fuel to make it to the moon and back. Again, the entire spacecraft would have landed on the moon.
- Lunar orbit rendezvous: This plan, which was adopted, is credited to John Houbolt and used the technique of 'Lunar Orbit Rendezvous' (LOR). The spacecraft was modular, composed of a 'Command/Service Module' (CSM) and a 'Lunar Module' (LM; originally Lunar Excursion Module ). The CSM contained the life support systems for the three man crew's five day round trip to the moon and the heat shield for their reentry to Earth's atmosphere. The LM would separate from the CSM in lunar orbit and carry two astronauts for the descent to the lunar surface, then back up to the CSM. In contrast with the other plans, the LOR plan required only a small part of the spacecraft to land on the moon, thereby minimizing the mass to be launched from the moon's surface for the return trip. The mass to be launched was further minimized by leaving part of the LM (that with the descent engine) behind, on the moon. The Lunar Module itself was composed of a descent stage and an ascent stage, the former serving as a launch platform for the latter when the lunar exploration party blasted off for lunar orbit where they would dock with the CSM prior to returning to Earth. The plan had the advantage that since the LM was to be eventually discarded, it could be made very light, so the moon mission could be launched with a single Saturn V rocket. However, at the time that LOR was decided, some mission planners were uneasy at the large numbers of dockings and undockings called for by the plan. To learn lunar landing techniques, astronauts practiced in the Lunar Landing Research Vehicle (LLRV), a flying vehicle that simulated (by means of a special, additional jet engine) the reduced gravity that the Lunar Module would actually fly in.

Flights

The Apollo program included eleven manned flights, designated Apollo 7 through Apollo 17, all launched from the Kennedy Space Center, Florida. Apollo 4 through Apollo 6 were unmanned test flights (officially there was no Apollo 2 or Apollo 3). The Apollo 1 designation was retroactively applied to the originally planned first manned flight which ended in a disastrous fire during a launch pad test that killed three astronauts, Virgil "Gus" Grissom, Edward White, and Roger B. Chaffee, in January 1967. The first of the manned flights employed the Saturn IB launch vehicle; the remaining flights all used the more powerful Saturn V. Two of the flights (Apollo 7 and Apollo 9) were Earth orbital missions, two of the flights (Apollo 8 and Apollo 10) were lunar orbital missions, and the remaining 7 flights were lunar landing missions (although one, Apollo 13, failed to land). Apollo 7 tested the Apollo command and service modules (CSM) in Earth orbit. Apollo 8 tested the CSM in lunar orbit. Apollo 9 tested the lunar module (LM) in earth orbit. Apollo 10 tested the LM in lunar orbit. Apollo 11 achieved the first human lunar landing. Apollo 12 achieved the first lunar landing at a precise location. Apollo 13 failed to achieve a lunar landing, but succeeded in returning the crew safely to earth following a potentially disastrous in-flight explosion. Apollo 14 resumed the lunar exploration program. Apollo 15 introduced a new level of lunar exploration capability, with a long-stay-time LM and a lunar roving vehicle. Apollo 16 was the first manned landing in the lunar highlands. Apollo 17, the final mission, was the first to include a scientist-astronaut, and the program's first manned night launch.

Apollo Applications Program

In the speech which initiated Apollo, Kennedy declared that no other program would have as great a long-range effect on America's ambitions in outer space. Following the success of Project Apollo, both NASA and its major contractors investigated several post-lunar applications for the Apollo hardware. The "Apollo Extension Series", later called the "Apollo Applications Program", proposed at least ten flights. Many of these would use the space that the lunar module took up in the Saturn rocket to carry scientific equipment. One plan involved using the Saturn IB to take the Command/Service Module (CSM) to a variety of low-earth orbits for missions lasting up to 45 days. Some missions would involve the docking of two CSMs, and transfer of supplies. The Saturn V would be necessary to take it to polar orbit, or sun-synchronous orbit (neither of which has yet been achieved by any manned spacecraft), and even to the geosynchronous orbit of Syncom 3, a communications satellite not quite in geostationary orbit. This was the first functioning communications satellite at that now-common great distance from the Earth, and it was small enough to be carried through the hatch and taken back to Earth for study as to the effects of radiation on its electronic components in that environment over a period of years. A return to the moon was also planned, this time to orbit for a longer time to map the surface with high-precision equipment. This mission would not include a landing. Of all the plans only two were implemented; the Skylab space station (May 1973 – February 1974), and the Apollo-Soyuz Test Project (July 1975). Skylab's fuselage was constructed from the second stage of a Saturn IB, and the station was equipped with the Apollo Telescope Mount, itself based on a lunar module. The station's three crews were ferried into orbit atop Saturn IBs, riding in CSMs; the station itself had been launched with a modified Saturn V. Skylab's last crew departed the station on February 8, 1974, whilst the station itself returned prematurely to Earth in 1979, by which time it had become the oldest operational Apollo component. The Apollo-Soyuz Test Project involved a docking in Earth orbit between an un-named CSM and a Soviet Soyuz spacecraft. The mission lasted from July 15 to July 24, 1975. Although the Soviet Union continued to operate the Soyuz and Salyut space vehicles, NASA's next manned mission would not be until STS-1 on April 12, 1981.

End of the program

1981 Originally three additional lunar landing missions had been planned, as Apollo 18 through Apollo 20. In light of the drastically shrinking NASA budget and the decision not to produce a second batch of Saturn Vs, these missions were cancelled to make funds available for the development of the Space Shuttle, and to make their Apollo spacecraft and Saturn V launch vehicles available to the Skylab program. Only one of the Saturn Vs was actually used; the others became museum exhibits. Another excerpt from Kennedy's Special Message to Congress: :"I believe we should go to the moon. But I think every citizen of this country as well as the Members of the Congress should consider the matter carefully in making their judgment, to which we have given attention over many weeks and months, because it is a heavy burden, and there is no sense in agreeing or desiring that the United States take an affirmative position in outer space, unless we are prepared to do the work and bear the burdens to make it successful. If we are not, we should decide today and this year. Skylab :"This decision demands a major national commitment of scientific and technical manpower, material and facilities, and the possibility of their diversion from other important activities where they are already thinly spread. It means a degree of dedication, organization and discipline which have not always characterized our research and development efforts. It means we cannot afford undue work stoppages, inflated costs of material or talent, wasteful interagency rivalries, or a high turnover of key personnel. :"New objectives and new money cannot solve these problems. They could in fact, aggravate them further--unless every scientist, every engineer, every serviceman, every technician, contractor, and civil servant gives his personal pledge that this nation will move forward, with the full speed of freedom, in the exciting adventure of space." (Excerpt from "Special Message to the Congress on Urgent National Needs")

Reasons for Apollo

The Apollo program was at least partly motivated by psycho-political considerations, in response to persistent perceptions of American inferiority in space technology vis-a-vis the Soviets, in the context of the Cold War and the Space Race. In this respect it succeeded brilliantly. In fact, American superiority in manned spaceflight was achieved in the precursory Gemini program, even before the first Apollo flight. The Apollo program stimulated many areas of technology. The flight computer design used in both the lunar and command modules was, along with the Minuteman Missile System, the driving force behind early research into integrated circuits. The fuel cell developed for this program was the first practical fuel cell. Computer controlled machining (CNC) was pioneered in fabricating Apollo structural components. Many astronauts and cosmonauts have commented on the profound effects that seeing earth from space has had on them. One of the most important legacies of the Apollo program was the now-common, but not universal view of Earth as a fragile, small planet, captured in the photographs taken by the astronauts during the lunar missions. The most famous of these photographs, taken by the Apollo 17 astronauts, is "The Blue Marble." These photographs have also motivated many people toward environmentalism and space colonization.

Miscellaneous information

- The cost of the entire Apollo program: USD $25.4 billion -1969 Dollars ($135-billion in 2005 Dollars). See NASA Budget. (Includes Mercury, Gemini, Ranger, Surveyor, Lunar Orbitar, Apollo programs.) Apollo spacecraft and Saturn rocket cost alone, was about $ 83-billion 2005 Dollars (Apollo spacecraft cost $ 28-billion (CS/M $ 17-billion; LM $ 11-billion), Saturn I, IB, V costs about $ 46-billion 2005 dollars).
- Amount of moon material brought back by the Apollo program: 381.7 kg (841.5 lb). Most of the material is stored at the Lunar Receiving Laboratory in Houston.

Missions

Lunar Receiving Laboratory The Apollo program used four types of launch vehicles:
- Little Joe II - unmanned suborbital launch escape system development.
- Saturn I - unmanned suborbital and orbital hardware development.
- Saturn IB - unmanned and manned earth orbit development and operational missions.
- Saturn V - unmanned and manned earth orbit and lunar missions. Something to note with Apollo flights is that Marshall Space Flight Center, which designed the Saturn rockets, referred to the flights as Saturn-Apollo (SA), while Kennedy Space Center referred to the flights as Apollo-Saturn (AS). This is why the unmanned Saturn 1 flights are referred to as SA and the unmanned Saturn 1B are referred to as AS. Dates given below are dates of launch.

Unmanned Saturn I

- SA-1 - October 27, 1961. Test of the S-1 Rocket
- SA-2 - April 25, 1962. Test of the S-1 Rocket and carried 109 m³ of water into the upper atmosphere to investigate effects on radio transmission and changes in local weather conditions.
- SA-3 - November 16, 1962. Same as SA-2
- SA-4 - March 28, 1963. Test effects of premature engine shutdown
- SA-5 - January 29, 1964. First flight of live second stage
- A-101 - May 28, 1964. Tested the structural integrity of a boilerplate Apollo Command and Service Module
- A-102 - September 18, 1964. Carried the first programmable computer on the Saturn I vehicle; last test flight
- A-103 - February 16, 1965. Carried Pegasus A micrometeorite satellite
- A-104 - May 25, 1965. Carried Pegasus B micrometeorite satellite
- A-105 - July 30, 1965. Carried Pegasus C micrometeorite satellite

Unmanned pad abort tests

1965
- Pad Abort Test-1 - November 7, 1963. Launch Escape System (LES) abort test from launch pad.
- Pad Abort Test-2 - June 29, 1965. LES pad abort test of near Block-I CM.

Unmanned Little Joe II

- QTV - August 28, 1963. Little Joe II qualification test.
- A-001 - May 13, 1964. LES transonic abort test.
- A-002 - December 8, 1964. LES maximum altitude, Max-Q abort test.
- A-003 - May 19, 1965. LES canard maximum altitude abort test.
- A-004 - January 20, 1966. LES test of maximum weight, tumbling Block-I CM.

Unmanned Apollo-Saturn IB and Saturn V

- AS-201 - February 26, 1966. First test flight of Saturn IB rocket
- AS-203 - July 5, 1966. Investigated effects of weightlessness on fuel tanks of S-IVB
- AS-202 - August 25, 1966. Sub-orbital test flight of Command and Service Module
- Apollo 4 - November 9, 1967. First test of the Saturn V booster
- Apollo 5 - January 22, 1968. Test of the Saturn IB booster and Lunar Module
- Apollo 6 - April 4, 1968. Test of the Saturn V booster

Manned

- Apollo 1 - Crew died in spacecraft fire atop launch vehicle during pre-launch tests on January 27, 1967.
- Apollo 7 - October 11, 1968. First manned Apollo flight, first manned flight of the Saturn IB.
- Apollo 8 - December 21, 1968. First manned flight around the Moon, first manned flight of the Saturn V.
- Apollo 9 - March 3, 1969. First manned flight of the Lunar Module.
- Apollo 10 - May 18, 1969. First manned flight of the Lunar Module around the Moon.
- Apollo 11 - July 16, 1969. First manned landing on the Moon, July 20.
- Apollo 12 - November 14, 1969. First precise manned landing on the Moon.
- Apollo 13 - April 11, 1970. Oxygen tank explodes en route, landing is cancelled, first (and, as of 2005, only) manned non-orbital lunar flight.
- Apollo 14 - January 31, 1971. Alan Shepard, the sole astronaut of the Mercury MR-3 mission, walks on the Moon.
- Apollo 15 - July 26, 1971. First mission with the Lunar Rover vehicle.
- Apollo 16 - April 16, 1972. First landing in the lunar highlands.
- Apollo 17 - December 7, 1972. Final Apollo lunar mission, first night launch, only mission with a professional geologist. The original pre-lunar landing program was more conservative but as the 'all-up' test flights for the Saturn V proved successful missions were deleted. The revised schedule published in October 1967 had the first manned Apollo CSM earth orbit mission (Apollo 7) followed by an Earth Orbit Rendezvo