122-467: A Mars sample-return ( MSR ) mission is a proposed mission to collect rock and dust samples on Mars and return them to Earth . Such a mission would allow more extensive analysis than that allowed by onboard sensors. Risks of cross-contamination of the Earth biosphere from returned Martian samples have been raised, though the risk of this occurring is considered to be low. The most recent concepts are
244-741: A NASA-ESA proposal ; a CNSA proposal, Tianwen-3 ; a Roscosmos proposal, Mars-Grunt ; and a JAXA proposal, Martian Moons eXploration (MMX). Although NASA and ESA's plans to return the samples to Earth are still in the design stage as of 2024, samples have been gathered on Mars by the Perseverance rover. Once returned to Earth, stored samples can be studied with the most sophisticated science instruments available. Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington, expect such studies to allow several new discoveries at many fields. Samples may be reanalyzed in
366-520: A lander originally manufactured for the canceled Mars Surveyor 2001 mission. Phoenix was one of four finalists selected out of 25 proposals. The four finalists were Phoenix, MARVEL, SCIM ( Sample Collection for Investigation of Mars ), and the ARES ("Aerial Regional-scale Environmental Survey") Mars airplane. SCIM was a sample return mission that would have used a free-return trajectory and aerogel to capture Mars dust and return it to Earth (see also:
488-428: A MSR mission in 2005. The same JPL author collaborated on a notional single-stage 200-kg MAV intended to be made small by using pump-fed propulsion to permit lightweight low-pressure liquid propellant tanks and compact high-pressure thrust chambers. This mass advantage of pump-fed operation was applied to a conceptual 100-kg MAV having a mass budget consistent with reaching Mars orbit using monopropellant, partly enabled by
610-495: A Mars sample-return mission. While ICAMSR acknowledges a low probability for biohazards, it considers the proposed containment measures to be unsafe. ICAMSR advocates more in situ studies on Mars, and preliminary biohazard testing at the International Space Station before the samples are brought to Earth. DiGregorio accepts the conspiracy theory of a NASA coverup regarding the discovery of microbial life by
732-522: A Martian solar day ( sol ) is equal to 24.6 hours, and a Martian solar year is equal to 1.88 Earth years (687 Earth days). Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos . The relatively flat plains in northern parts of Mars strongly contrast with the cratered terrain in southern highlands – this terrain observation is known as the Martian dichotomy . Mars hosts many enormous extinct volcanoes (the tallest
854-567: A better solution. China has announced plans for a Mars sample-return mission to be called Tianwen-3 . The mission would launch in late-2028, with a lander and ascent vehicle on a Long March 5 and an orbiter and return module launched separately on a Long March 3B . Samples would be returned to Earth in July 2031. A previous plan would have used a large spacecraft that could carry out all mission phases, including sample collection, ascent, orbital rendezvous, and return flight. This would have required
976-502: A campaign to deposit 10 of its collected samples to the backup depot, Three Forks to ensure if Perseverance runs into problems, the MSR campaign could still succeed. The NASA-ESA plan is to return samples using three missions: a sample collection mission (Perseverance) launched in 2020 and currently operational, a sample retrieval mission (Sample Retrieval Lander + Mars ascent vehicle + Sample Transfer arm + 2 Ingenuity class helicopters), and
1098-489: A classical albedo feature it contains. In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft . A related, but much more detailed, global Mars map was released by NASA on 16 April 2023. The vast upland region Tharsis contains several massive volcanoes, which include the shield volcano Olympus Mons . The edifice is over 600 km (370 mi) wide. Because
1220-418: A concept that would launch a 9.5-metric-ton payload from Earth, including a Mars orbiter for Earth return, and a lander having a 400-kg rover and a "Mars return vehicle" that would mass over 2 metric tons. A 20-kg sample canister would arrive at Earth containing 5 kg of samples including scientific-quality cores drilled from every type of Mars terrain. In the late 1980s, multiple NASA centers contributed to
1342-494: A detailed analysis of conventional small-scale rocket technology (both solid and liquid propellant) found that known propulsion components would be too heavy to build a MAV as lightweight as several hundred kilograms and "The application of launch vehicle design principles to the development of new hardware on a tiny scale" was suggested. In 1998, JPL presented a design for a two-stage pressure-fed liquid bipropellant MAV that would be 600 kilograms or less at Mars liftoff, intended for
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#17327796329671464-480: A few milliseconds, they start to dig trenches, launch small rocks up into the landing gear, and cause destabilizing backpressure to be forced upon the lander. Finding an adequate landing site means being able to estimate rock size from orbit. The technology to accurately determine rock size under 0.5 meters in diameter from orbit has not yet been developed, so instead rock size distribution is inferred from its relationship to thermal inertia, based on thermal response of
1586-422: A global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions as is the case on Earth, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled , and were associated with an aurora 25 times brighter than any observed earlier, due to
1708-488: A high ratio of deuterium in Gale Crater , though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water. Near the northern polar cap is the 81.4 kilometres (50.6 mi) wide Korolev Crater , which
1830-429: A landing craft can be decelerated enough to allow adequate time for other necessary landing processes to be carried out before landing. Mars' atmosphere varies significantly over the course of a Mars year , which prevents engineers from being able to develop a system for EDL common among all missions. Frequently-occurring dust storms increase lower atmospheric temperature and lessen atmospheric density, which, coupled with
1952-464: A launch from Earth in 1998 with a MAV mass in the range 1400 to 1500 kg including a pump-fed first stage and a pressure-fed second stage. The United States' Mars Exploration Program , formed after Mars Observer 's failure in September 1993, supported a Mars sample return. One architecture was proposed by Glenn J. MacPherson in the early 2000s. In 1996, the possibility of life on Mars
2074-490: A low of 30 Pa (0.0044 psi ) on Olympus Mons to over 1,155 Pa (0.1675 psi) in Hellas Planitia , with a mean pressure at the surface level of 600 Pa (0.087 psi). The highest atmospheric density on Mars is equal to that found 35 kilometres (22 mi) above Earth's surface. The resulting mean surface pressure is only 0.6% of Earth's 101.3 kPa (14.69 psi). The scale height of
2196-442: A massive, and unexpected, solar storm in the middle of the month. Mars has seasons, alternating between its northern and southern hemispheres, similar to on Earth. Additionally the orbit of Mars has, compared to Earth's, a large eccentricity and approaches perihelion when it is summer in its southern hemisphere and winter in its northern, and aphelion when it is winter in its southern hemisphere and summer in its northern. As
2318-542: A minimum thickness of 6 kilometres (3.7 mi) in Isidis Planitia , and a maximum thickness of 117 kilometres (73 mi) in the southern Tharsis plateau. For comparison, Earth's crust averages 27.3 ± 4.8 km in thickness. The most abundant elements in the Martian crust are silicon , oxygen , iron , magnesium , aluminium , calcium , and potassium . Mars is confirmed to be seismically active; in 2019 it
2440-575: A mission included a sample-return mission where soil samples are placed in Mars orbit in the late 2020s or early 2030s, an in-situ soil analysis, and a study of Mars' surface and deep interior preceding a sample-return mission and/or crewed mission. Concept missions that were studied that fit the budget requirement of US$ 700 million to US$ 800 million included the Next Mars Orbiter (NeMO) to replace aging satellites' telecommunication services, and
2562-449: A mission involving returning a sample of Mars soil to Earth, which would likely cost at least $ 5 billion and take ten years to complete. According to NASA, there are four broad goals of the MEP, all having to do with understanding the potential for life on Mars. Mars exploration missions have historically had some of the highest failure rates for NASA missions, which can be attributed to
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#17327796329672684-452: A probe to the surface of Mars, nicknamed "Marsnik 1," was by the USSR in 1960. The probe failed to reach Earth orbit, and the mission was ultimately unsuccessful. Failure to complete mission objectives has been common in missions designed to explore Mars; roughly two-thirds of all spacecraft destined for Mars have failed before any observation could begin. The Mars Exploration Program itself
2806-475: A program-level architecture for robotic exploration of Mars that is consistent with the Obama administration's challenge of sending humans to Mars orbit in the decade of the 2030s , yet remain responsive to the primary scientific goals of the 2011 NRC Decadal Survey for Planetary Science. The MPPG used non-consensus, individual inputs of both NASA civil servant and contractor employees, with resulting decisions being
2928-505: A proposed Mars Rover Sample Return mission (MRSR). As described by JPL authors, one option for MRSR relied on a single launch of a 12-ton package including a Mars orbiter and Earth return vehicle, a 700-kg rover, and a 2.7-ton Mars ascent vehicle (MAV) which would use pump-fed liquid propulsion for a significant mass saving. A 20-kg sample package on the MAV was to contain 5 kg of Mars soil. A Johnson Space Center author subsequently referred to
3050-473: A record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava. One of the larger examples, Ma'adim Vallis , is 700 kilometres (430 mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12 mi) and a depth of 2 kilometres (1.2 mi) in places. It
3172-588: A remnant of that ring. The geological history of Mars can be split into many periods, but the following are the three primary periods: Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 million years ago. Water flows in the grabens called the Cerberus Fossae occurred less than 20 million years ago, indicating equally recent volcanic intrusions. The Mars Reconnaissance Orbiter has captured images of avalanches. Mars
3294-460: A result, the seasons in its southern hemisphere are more extreme and the seasons in its northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30 °C (54 °F). Martian surface temperatures vary from lows of about −110 °C (−166 °F) to highs of up to 35 °C (95 °F) in equatorial summer. The wide range in temperatures
3416-481: A return mission (Earth Return Orbiter). Although NASA and ESA's proposal is still in the design stage, the first leg of gathering samples is currently being executed by the Perseverance rover on Mars and components of the sample retrieval lander (second leg) are in testing phase on earth. The later phases were facing significant cost overruns as of August 2023. In November 2023, NASA was reported to have cut back
3538-468: A small Mars orbiter for rendezvous and return to Earth. Robert Zubrin , a long-time advocate for human Mars missions, concluded in 1996 that the best approach to MSR would be launching directly to Earth using propellants made on Mars, because a rendezvous in Mars orbit would be too risky and he estimated that a direct-return MAV would mass 500 kg, too heavy to send to Mars affordably if fully fueled on Earth. International peer reviewers concurred. In 1997,
3660-471: A small crater (later called Airy-0 ), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton E. Davies , Harold Masursky , and Gérard de Vaucouleurs for the definition of 0.0° longitude to coincide with the original selection. Because Mars has no oceans, and hence no " sea level ", a zero-elevation surface had to be selected as a reference level; this is called
3782-769: A stationary lander to investigate and select samples suitable for a later return to Earth. Prior to the findings of the MPPG, the House Appropriations Committee's Commerce-Justice-Science subcommittee approved a budget in April 2012 that reinstated US$ 150 million to the Planetary Science budget, with a caveat that a sample-return mission be mandated. The MPPG's final report was drafted in August 2012 and published in September. Ultimately endorsing
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3904-481: A storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase global temperature. Seasons also produce dry ice covering polar ice caps . Large areas of the polar regions of Mars While Mars contains water in larger amounts , most of it is dust covered water ice at the Martian polar ice caps . The volume of water ice in
4026-491: A very thick lithosphere compared to Earth. Below this the mantle gradually becomes more ductile, and the seismic wave velocity starts to grow again. The Martian mantle does not appear to have a thermally insulating layer analogous to Earth's lower mantle ; instead, below 1050 km in depth, it becomes mineralogically similar to Earth's transition zone . At the bottom of the mantle lies a basal liquid silicate layer approximately 150–180 km thick. Mars's iron and nickel core
4148-471: A year, there are large surface temperature swings on the surface between −78.5 °C (−109.3 °F) to 5.7 °C (42.3 °F) similar to Earth's seasons , as both planets have significant axial tilt . Mars was formed approximately 4.5 billion years ago. During the Noachian period (4.5 to 3.5 billion years ago), Mars's surface was marked by meteor impacts , valley formation, erosion, and
4270-475: Is Mars-Grunt . It adopted Fobos-Grunt design heritage. 2011 plans envisioned a two-stage architecture with an orbiter and a lander (but no roving capability), with samples gathered from around the lander by a robotic arm. Whether life forms exist on Mars is unresolved. Thus, MSR could potentially transfer viable organisms to Earth, resulting in back contamination — the introduction of extraterrestrial organisms into Earth's biosphere . The scientific consensus
4392-486: Is Olympus Mons , 21.9 km or 13.6 mi tall) and one of the largest canyons in the Solar System ( Valles Marineris , 4,000 km or 2,500 mi long). Geologically , the planet is fairly active with marsquakes trembling underneath the ground, dust devils sweeping across the landscape, and cirrus clouds . Carbon dioxide is substantially present in Mars's polar ice caps and thin atmosphere . During
4514-452: Is Syrtis Major Planum . The permanent northern polar ice cap is named Planum Boreum . The southern cap is called Planum Australe . Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich ), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972,
4636-406: Is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre , which is around 1,800 kilometres (1,100 mi) in diameter, and Isidis , which is around 1,500 kilometres (930 mi) in diameter. Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to
4758-459: Is almost impossible to find on Mars, landing gear must be very stable and have enough ground clearance to prevent problems with tipping over and instability upon landing. In addition, the deceleration systems of these landers would need to include thrusters that are pointed at the ground. These thrusters must be designed so that they only need to be active for an extremely short amount of time; if they are active and pointed at rocky ground for more than
4880-432: Is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass , resulting in about 38% of Earth's surface gravity . Mars is the only presently known example of a desert planet , a rocky planet with a surface akin to that of Earth's hot deserts . The red-orange appearance of
5002-766: Is completely molten, with no solid inner core. It is around half of Mars's radius, approximately 1650–1675 km, and is enriched in light elements such as sulfur , oxygen, carbon , and hydrogen . Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals , and other elements that typically make up rock . The Martian surface is primarily composed of tholeiitic basalt , although parts are more silica -rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar , with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of
Mars sample-return mission - Misplaced Pages Continue
5124-429: Is 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
5246-426: Is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure (about 1% that of the atmosphere of Earth ), and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight. Mars has the largest dust storms in the Solar System, reaching speeds of over 160 km/h (100 mph). These can vary from
5368-556: Is orange-red because it is covered in iron(III) oxide dust, giving it the nickname " the Red Planet ". Mars is among the brightest objects in Earth's sky , and its high-contrast albedo features have made it a common subject for telescope viewing. It is classified as a terrestrial planet and is the second smallest of the Solar System 's planets with a diameter of 6,779 km (4,212 mi). In terms of orbital motion,
5490-519: Is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon . If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300 mi) in size, or roughly
5612-576: Is that the potential for large-scale effects, either through pathogenesis or ecological disruption, is small. Returned samples would be treated as potentially biohazardous until scientists decide the samples are safe. The goal is that the probability of release of a Mars particle is less than one in a million. The proposed NASA Mars sample-return mission will not be approved by NASA until the National Environmental Policy Act (NEPA) process has been completed. Furthermore, under
5734-606: Is thought to have been carved by flowing water early in Mars's history. The youngest of these channels is thought to have formed only a few million years ago. Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation
5856-556: Is to use the thermal protection system to cushion the capsule upon impact (at terminal velocity ). The sample container would be designed to withstand the force of impact. To receive the returned samples, NASA proposed a custom Biosafety Level 4 containment facility, the Mars Sample-Return Receiving facility (MSRRF). Other scientists and engineers, notably Robert Zubrin of the Mars Society , argued in
5978-461: The Journal of Cosmology that contamination risk is functionally zero leaving little need to worry. They cite, among other things, lack of any known incident although trillions of kilograms of material have been exchanged between Mars and Earth via meteorite impacts. The International Committee Against Mars Sample Return (ICAMSR) is an advocacy group led by Barry DiGregorio, that campaigns against
6100-490: The Stardust mission). MARVEL was an orbiter that would have searched for volcanism as well as analyzed various components of the Mars atmosphere. The name is an acronym for Mars Volcanic Emission and Life Scout , and it was intended to detect gases from life if it was there. ARES was an aircraft concept for Mars to study the lower atmosphere and surface. On September 15, 2008, NASA announced that it had selected MAVEN for
6222-550: The areoid of Mars, analogous to the terrestrial geoid . Zero altitude was defined by the height at which there is 610.5 Pa (6.105 mbar ) of atmospheric pressure. This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm). For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles , each named for
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#17327796329676344-644: The International Mars Exploration Working Group (IMEWG) to outline the scientific and engineering requirements of an internationally sponsored and executed Mars sample-return mission in the 2018–2023 time frame. In October 2009, NASA and ESA established the Mars Exploration Joint Initiative to proceed with the ExoMars program, whose ultimate aim is "the return of samples from Mars in
6466-479: The Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530 cu mi) of water ice. Mars Exploration Program Mars Exploration Program ( MEP ) is a long-term effort to explore the planet Mars , funded and led by NASA . Formed in 1993, MEP has made use of orbital spacecraft , landers , and Mars rovers to explore the possibilities of life on Mars , as well as
6588-452: The N1 rocket that would have launched it. Another sample-return mission, Mars 5M (Mars-79), planned for 1979, was cancelled due to complexity and technical problems. In the mid-1980's, JPL mission planners noted that MSR had been "pushed by budgetary and other pressures into the '90s," and that the round trip would "impose large propulsion requirements." They presented a notional mass budget for
6710-678: The Perseverance rover in the Jezero crater in February 2021. It has collected multiple samples and will continue to do so, packing them into cylinders for later return in the MSR Campaign. Jezero appears to be an ancient lakebed, suitable for ground sampling. It is also assigned the task to return the samples directly to the Sample Return lander, considering its potential mission longevity. From December 21, 2022, Perseverance started
6832-656: The Yellowknife Bay area in the Glenelg terrain. In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae , based on spectrometer readings of the darkened areas of slopes. These streaks flow downhill in Martian summer, when the temperature is above −23 °C, and freeze at lower temperatures. These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below
6954-415: The asteroid belt , so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets , i.e. , those that lie within the orbit of Jupiter . Martian craters can have a morphology that suggests the ground became wet after the meteor impact. The large canyon, Valles Marineris (Latin for " Mariner Valleys", also known as Agathodaemon in
7076-426: The atmosphere of Mars is about 100 times thinner. As a result, if a landing craft were to descend into Mars' atmosphere, it would decelerate at a much lower altitude, and depending on the object's mass, may not have enough time to reach terminal velocity. In order to deploy super- or subsonic decelerators, velocity must be below a threshold or they will not be effective. Therefore, technologies must be developed so that
7198-469: The possible presence of water oceans . The Hesperian period (3.5 to 3.3–2.9 billion years ago) was dominated by widespread volcanic activity and flooding that carved immense outflow channels . The Amazonian period, which continues to the present, has been marked by the wind as a dominant influence on geological processes . Due to Mars's geological history, the possibility of past or present life on Mars remains of great scientific interest. Since
7320-448: The 1976 Viking landers . DiGregorio also supports a view that several pathogens – such as common viruses – originate in space and probably caused some mass extinctions and pandemics . These claims connecting terrestrial disease and extraterrestrial pathogens have been rejected by the scientific community. Mars Mars is the fourth planet from the Sun . The surface of Mars
7442-524: The 2020s no such mission is planned. Scientists have theorized that during the Solar System's formation , Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine , phosphorus , and sulfur , are much more common on Mars than on Earth; these elements were probably pushed outward by
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#17327796329677564-569: The 2020s". ExoMars's first mission was planned to launch in 2018 with unspecified missions to return samples in the 2020–2022 time frame. The cancellation of the caching rover MAX-C in 2011, and later NASA withdrawal from ExoMars, due to budget limitations, ended the mission. The pull-out was described as "traumatic" for the science community. In early 2011, the US National Research Council 's Planetary Science Decadal Survey , which laid out mission planning priorities for
7686-540: The Earth return orbiter. The orbiter would capture the sample containers delivered by both MAVs and place them in separate Earth entry vehicles. This mission concept, considered by NASA's Mars Exploration Program to return samples by 2008, was cancelled following a program review. In mid-2006, the International Mars Architecture for the Return of Samples (iMARS) Working Group was chartered by
7808-591: The Late Heavy Bombardment. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300 mi), or roughly four times the size of the Moon's South Pole–Aitken basin , which would be the largest impact basin yet discovered if confirmed. It has been hypothesized that the basin was formed when Mars was struck by a Pluto -sized body about four billion years ago. The event, thought to be
7930-741: The Mars Exploration Program Analysis Group (MEPAG) enables the scientific community to provide input for the planning and prioritizing of the Mars Exploration Program. Mars exploration missions, as do most NASA missions, can be fairly costly. For example, NASA's Curiosity rover (landed on Mars in Aug 2012) has a budget exceeding $ 2.5 billion. NASA also has goals of collaborating with the European Space Agency (ESA) in order to conduct
8052-478: The Martian ionosphere , lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Express have detected ionized atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from
8174-538: The Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron oxide particles suspended in it. The concentration of methane in the Martian atmosphere fluctuates from about 0.24 ppb during the northern winter to about 0.65 ppb during the summer. Estimates of its lifetime range from 0.6 to 4 years, so its presence indicates that an active source of the gas must be present. Methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and
8296-415: The Martian surface is caused by ferric oxide , or rust . It can look like butterscotch ; other common surface colors include golden, brown, tan, and greenish, depending on the minerals present. Like Earth, Mars is differentiated into a dense metallic core overlaid by less dense rocky layers. The outermost layer is the crust, which is on average about 42–56 kilometres (26–35 mi) thick, with
8418-542: The Moon, Johann Heinrich von Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew the first map of Mars. Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to
8540-472: The algorithms that target the touchdown point of the lander can be "tricked" into releasing the lander too early or late if the craft passes over mesas or trenches while descending. While it was observed in ancient times by the Babylonians , Egyptians , Greeks , and others, it was not until the invention of the telescope in the 17th century that Mars was studied in depth. The first attempt at sending
8662-462: The area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South Pole–Aitken basin as the largest impact crater in the Solar System. Mars is scarred by a number of impact craters: a total of 43,000 observed craters with a diameter of 5 kilometres (3.1 mi) or greater have been found. The largest exposed crater is Hellas , which is 2,300 kilometres (1,400 mi) wide and 7,000 metres (23,000 ft) deep, and
8784-419: The atmosphere is about 10.8 kilometres (6.7 mi), which is higher than Earth's 6 kilometres (3.7 mi), because the surface gravity of Mars is only about 38% of Earth's. The atmosphere of Mars consists of about 96% carbon dioxide , 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 μm in diameter which give
8906-406: The atmosphere is small, but enough to produce larger clouds of water ice and different cases of snow and frost , often mixed with snow of carbon dioxide dry ice . Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels , cut across the surface in about 25 places. These are thought to be
9028-467: The broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock . Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24 in), during the rover's traverse from the Bradbury Landing site to
9150-549: The cancellation of the agency's participation in ESA's ExoMars program, as well as a reevaluation of the Mars Exploration Program as a whole. In February 2012, the Mars Program Planning Group (MPPG) was convened in Washington, D.C. to discuss candidate mission concepts for the 2018 or 2020 launch window, in an initiative known as Mars Next Generation. The purpose of the MPPG was to develop foundations for
9272-466: The cause of the Martian hemispheric dichotomy , created the smooth Borealis basin that covers 40% of the planet. A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago. This ring system may have been formed from a moon, 20 times more massive than Phobos , orbiting Mars billions of years ago; and Phobos would be
9394-448: The costs of reproducing environments in which this data would be relevant in terms of Mars' environment are considerably high, resulting in testing being purely ground-based or simulating results of tests involving technologies derived from past missions. The surface of Mars is extremely uneven, containing rocks , mountainous terrain, and craters. For a landing craft, the ideal landing area would be flat and debris-free. Since this terrain
9516-458: The edges of boulders and other obstacles in their path. The commonly accepted hypotheses include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils . Several other explanations have been put forward, including those that involve water or even the growth of organisms. Environmental radiation levels on the surface are on average 0.64 millisieverts of radiation per day, and significantly less than
9638-544: The exclusive responsibility of NASA. The immediate focus of the MPPG was on the collection of multiple mission concept options for the 2018 and 2020 Mars launch window. At a budget envelope of $ 700 million USD , including a launch vehicle , it was presumed that the mission would be limited to an orbiter . Near-term ideas were taken into consideration for early mission planning in the 2018-2024 timeframe, while mid- to longer-term ideas informed program-level architecture planning for 2026 and beyond. Strategies explored for such
9760-473: The extremely variable elevations on Mars' surface, forces a conservative selection of a landing site in order to allow for sufficient craft deceleration. With Mars EDL sequences only lasting about 5–8 minutes, the associated systems must be unquestionably reliable. Ideally, this would be verified by data obtained by carrying out large-scale tests of various components of the EDL systems on Earth-based testing. However,
9882-429: The flanks of the volcano Arsia Mons . The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from 100 to 252 metres (328 to 827 ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315 ft) deep. Because light does not reach the floor of most of the caves, they may extend much deeper than these lower estimates and widen below
10004-507: The future by instruments that do not yet exist. In 2006, the Mars Exploration Program Analysis Group identified 55 important investigations related to Mars exploration. In 2008, they concluded that about half of the investigations "could be addressed to one degree or another by MSR", making MSR "the single mission that would make the most progress towards the entire list" of investigations. Moreover, it
10126-462: The immense engineering challenges of these missions as well as some bad luck, such as the America's Mars Polar Lander . With many of the goals of the MEP involving entry, descent, and landing of spacecraft (EDL) on the surface of Mars, factors like the planet's atmosphere, uneven surface terrain, and high cost of replicating Mars-like environments for testing come into play. Compared to the Earth,
10248-436: The lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% perchlorate by weight, concentrations that are toxic to humans . Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow
10370-465: The landing site measured by satellites currently orbiting Mars. The Mars Reconnaissance Orbiter also helps this cause in the sense that its cameras can see rocks larger than 0.5 m in diameter. Along with the possibility of the lander tipping over on sloped surfaces, large topographical features like hills, mesas, craters and trenches pose the problem of interference with ground sensors. Radar and Doppler radar can falsely measure altitude during descent and
10492-567: The late 20th century, Mars has been explored by uncrewed spacecraft and rovers , with the first flyby by the Mariner 4 probe in 1965, the first orbit by the Mars 2 probe in 1971, and the first landing by the Viking 1 probe in 1976. As of 2023, there are at least 11 active probes orbiting Mars or on the Martian surface. Mars is an attractive target for future human exploration missions , though in
10614-474: The mineral jarosite . This forms only in the presence of acidic water, showing that water once existed on Mars. The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum , which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity. It is estimated that the amount of water in
10736-553: The mineral olivine , which is known to be common on Mars, or by Martian life. Compared to Earth, its higher concentration of atmospheric CO 2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240 m/s for frequencies below 240 Hz, and 250 m/s for those above. Auroras have been detected on Mars. Because Mars lacks
10858-427: The mountain is so large, with complex structure at its edges, giving a definite height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21 km (13 mi), a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia , over 1,000 km (620 mi) to
10980-431: The movement of dry dust. No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active. Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history. Such conditions necessarily require
11102-514: The northwest, to the summit approaches 26 km (16 mi), roughly three times the height of Mount Everest , which in comparison stands at just over 8.8 kilometres (5.5 mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System ; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta , at 20–25 km (12–16 mi). The dichotomy of Martian topography
11224-468: The old canal maps ), has a length of 4,000 kilometres (2,500 mi) and a depth of up to 7 kilometres (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277 mi) long and nearly 2 kilometres (1.2 mi) deep. Valles Marineris was formed due to
11346-842: The past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors . One hypothesis, published in 1999 and re-examined in October ;2005 (with the help of the Mars Global Surveyor ), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded. The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium , sodium , potassium and chlorine . These nutrients are found in soils on Earth. They are necessary for growth of plants. Experiments performed by
11468-685: The period 2013–2022, declared an MSR campaign its highest priority Flagship Mission for that period. In particular, it endorsed the proposed Mars Astrobiology Explorer-Cacher (MAX-C) mission in a "descoped" (less ambitious) form. This mission plan was officially cancelled in April 2011. A key mission requirement for the Mars 2020 Perseverance rover mission was that it help prepare for MSR. The rover landed on 18 February 2021 in Jezero Crater to collect samples and store them in 43 cylindrical tubes for later retrieval. The Mars 2020 mission landed
11590-662: The planet's climate and natural resources . The program is managed by NASA's Science Mission Directorate by Doug McCuistion of the Planetary Science Division . As a result of 40% cuts to NASA's budget for fiscal year 2013, the Mars Program Planning Group (MPPG) was formed to help reformulate the MEP, bringing together leaders of NASA's technology, science, human operations, and science missions. First convening in October 1999,
11712-412: The program due to a possible shortage of funds. As of January 2024, the plan was facing ongoing scrutiny due to budget and scheduling considerations, and a new overhaul plan was being pursued. In April 2024, NASA reported that the originally projected cost of $ 7 billion and expected sample return of 2033 was updated to an unacceptable $ 11 billion and return of 2040 instead, prompting the agency to search for
11834-566: The radiation of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars. For comparison the radiation levels in low Earth orbit , where Earth's space stations orbit, are around 0.5 millisieverts of radiation per day. Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day, featuring lava tubes southwest of Hadriacus Mons with potentially levels as low as 0.064 millisieverts per day, comparable to radiation levels during flights on Earth. Although better remembered for mapping
11956-479: The return of geological samples from Mars. One early concept was the Sample Collection for Investigation of Mars (SCIM) proposal, which involved sending a spacecraft in a grazing pass through Mars's upper atmosphere to collect dust and air samples without landing or orbiting. The Soviet Union considered a Mars sample-return mission, Mars 5NM , in 1975 but it was cancelled due to the repeated failures of
12078-649: The samples as part of a joint mission with other countries. On 9 June 2015, the Japanese Aerospace Exploration Agency (JAXA) unveiled a plan named Martian Moons Exploration (MMX) to retrieve samples from Phobos or Deimos . Phobos's orbit is closer to Mars and its surface may have captured particles blasted from Mars. The launch from Earth is planned for September 2024, with a return to Earth in 2029. Japan has also shown interest in participating in an international Mars sample-return mission. A Russian Mars sample-return mission concept
12200-702: The second mission. This mission was budgeted at no more than US$ 475 million. After only two selections, the NASA Science Directorate announced in 2010 that Mars Scout would be incorporated into the Discovery program , which was re-scoped to allow Mars missions to be proposed. InSight , a Mars seismology and geology mission, was ultimately chosen as the twelfth Discovery program mission. A significant budget cut of US$ 300 million to NASA's planetary science division occurred in FY2013, which prompted
12322-436: The simplicity of a single tank, also applicable to Mars landing typically done with monopropellant. The high-pressure thrusters and pump had previously been demonstrated in the 1994 flight of an experimental 21-kg rocket. As of late 1999, the MSR mission was anticipated to be launched from Earth in 2003 and 2005. Each was to deliver a rover and a Mars ascent vehicle, and a French supplied Mars orbiter with Earth return capability
12444-467: The size of Earth's Arctic Ocean . This finding was derived from the ratio of protium to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium (D/H = 9.3 ± 1.7 10 ) is five to seven times the amount on Earth (D/H = 1.56 10 ), suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found
12566-422: The south polar ice cap, if melted, would be enough to cover most of the surface of the planet with a depth of 11 metres (36 ft). Water in its liquid form cannot prevail on the surface of Mars due to the low atmospheric pressure on Mars, which is less than 1% that of Earth, only at the lowest of elevations pressure and temperature is high enough for water being able to be liquid for short periods. Water in
12688-461: The southern highlands include detectable amounts of high-calcium pyroxenes . Localized concentrations of hematite and olivine have been found. Much of the surface is deeply covered by finely grained iron(III) oxide dust. Although Mars has no evidence of a structured global magnetic field , observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in
12810-484: The spacecraft had been scheduled to enter orbit . In the 2000s, NASA established the Mars Scout Program as a campaign under the Mars Exploration Program to send a series of small, low-cost robotic missions to Mars , competitively selected from innovative proposals by the scientific community with a budget cap of US$ 485 million. The first robotic spacecraft in this program was Phoenix , which utilized
12932-505: The study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; smaller valleys are named for rivers. 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). The surface of Mars as seen from Earth
13054-401: The super-heavy-lift Long March 9 launch vehicle. Another plan involved using Tianwen-1 to cache the samples for retrieval. France has worked towards a sample return for many years. This included concepts of an extraterrestrial sample curation facility for returned samples, and numerous proposals. They worked on the development of a Mars sample-return orbiter, which would capture and return
13176-513: The surface. However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process. A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive. Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been
13298-430: The surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430 ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface. Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with
13420-625: The swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben , but a plate boundary where 150 kilometres (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two- tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on
13542-468: The terms of Article VII of the Outer Space Treaty and other legal frameworks, were a release of organisms to occur, the releasing nation(s) would be liable for any resultant damages. The sample-return mission would be tasked with preventing contact between the Martian environment and the exterior of the sample containers. In order to eliminate the risk of parachute failure, the current plan
13664-507: The upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200–1,000 metres (660–3,280 ft). On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration , likely hydrated calcium sulfate , in several rock samples including
13786-420: The widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence. Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite , both of which sometimes form in the presence of water. In 2004, Opportunity detected
13908-414: The young Sun's energetic solar wind . After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment . About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. However, more recent modeling has disputed the existence of
14030-554: Was formed officially in the wake of the failed Mars Observer in September 1992, which had been NASA's first Mars mission since the Viking 1 and Viking 2 projects in 1975. The spacecraft, which was based on a modified Earth-orbiting commercial communications satellite (i.e., SES's Astra 1A satellite), carried a payload of instruments designed to study the geology, geophysics, and climate of Mars from orbit. The mission ended in August 1993 when communications were lost three days before
14152-629: Was probably the root cause of the incision in almost all cases. Along craters and canyon walls, there are thousands of features that appear similar to terrestrial gullies . The gullies tend to be in the highlands of the Southern Hemisphere and face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice, although others have argued for formation mechanisms involving carbon dioxide frost or
14274-401: Was raised when apparent microfossils were thought to have been found in Mars meteorite, ALH84001 . This hypothesis was eventually rejected, but led to a renewed interest in a Mars sample return. In the mid-1990s, NASA funded JPL and Lockheed Martin to study affordable small-scale MSR mission architectures including a concept to return 500 grams of Mars samples using a 100-kg MAV that would meet
14396-437: Was reported that InSight had detected and recorded over 450 marsquakes and related events. Beneath the crust is a silicate mantle responsible for many of the tectonic and volcanic features on the planet's surface. The upper Martian mantle is a low-velocity zone , where the velocity of seismic waves is lower than surrounding depth intervals. The mantle appears to be rigid down to the depth of about 250 km, giving Mars
14518-597: Was reported that a significant fraction of the investigations could not be meaningfully advanced without returned samples. One source of Mars samples is what are thought to be Martian meteorites , which are rocks ejected from Mars that made their way to Earth. As of August 2023, 356 meteorites had been identified as Martian, out of over 79,000 known meteorites. These meteorites are believed to be from Mars because their elemental and isotopic compositions are similar to rocks and atmospheric gases analyzed on Mars. Returning from Mars appeared in technical literature when Apollo
14640-498: Was still in development and the first spacecraft to fly past Mars had not yet launched, with an expectation that people would be on board for Mars ascent. The density of the Mars atmosphere remained unknown at that time, so the Lockheed engineering author reported the analysis of trajectory options over a range of aerodynamic drag conditions for a 15-ton launch vehicle to reach a rendezvous orbit. At NASA, returning samples from Mars
14762-734: Was studied jointly by the Langley Research Center and the Jet Propulsion Laboratory in the early 1970s during the time that the Viking Mars lander mission was in development, and a Langley author noted that the "Mars surface-to-orbit launch vehicle" would need high performance because its mass would "have a substantial impact on the mass and systems requirements" for earlier mission phases, delivery of that vehicle to Mars and launch preparations on Mars. For at least three decades, scientists have advocated
14884-436: Was to be included in 2005. The 140-kg MAV, "in the process of being contracted to industry" at that time, was to include telemetry on its first stage and thrusters that would spin the vehicle to 300 RPM before separation of the simplified lightweight upper stage. Atop each MAV, a 3.6-kg, 16-cm diameter spherical payload would contain 500 grams of samples and have solar cells to power a long-life beacon to facilitate rendezvous with
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