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35-582: Because the Borealis basin covers 40% of the surface of Mars, and much of the Northern Hemisphere, many currently recognized regions of Mars lie within it: One possible explanation for the basin's low, flat and relatively crater-free topography is that the basin was formed by a single large impact. Two simulations of a possible impact sketched a profile for the collision: low velocity—6 to 10 km (3.7 to 6.2 mi) per second—oblique angle and

70-516: A periapsis of 262 km (163 mi) above the northern hemisphere, and an apoapsis of 54,026 km (33,570 mi) above the southern hemisphere. This would subsequently be adjusted into its circular science orbit. After orbital insertion, MGS performed a series of orbit changes to lower the periapsis of its orbit into the upper fringes of the Martian atmosphere at an altitude of about 110 km (68 mi). During every atmospheric pass,

105-437: A diameter of 1,600–2,700 km (990–1,680 mi). Topographical data from Mars Global Surveyor are consistent with the models and also suggest that the elliptical crater has axes of length 10,600 km (6,600 mi) and 8,500 km (5,300 mi), centered on 67°N 208°E  /  67°N 208°E  / 67; 208 , though this has been partially obscured by later volcanic eruptions that created

140-426: A general increase in the rate of crustal formation for a period of 40 million years following the impact. Such a large impact would have disturbed the mantle , altering the normal convection currents and causing upwellings which further increase the amount of melting at the impact site. Overall, such an event would actually increase the rate of cooling of the Martian interior. The lack of magnetic anomalies observed in

175-464: A test of the general relativistic Lense–Thirring precession which consists of a small precession of the orbital plane of a test particle moving around a central, rotating mass such as a planet. The interpretation of these results has been debated. Hundreds of gullies were discovered that were formed from liquid water, possibly in recent times. A few channels on Mars displayed inner channels that suggest sustained fluid flows. The most well-known

210-428: Is almost perfectly circular, moved from the south pole to the north pole in just under an hour. The altitude was chosen to make the orbit Sun-synchronous, so that all images that were taken by the spacecraft of the same surface features on different dates were taken under identical lighting conditions. After each orbit, the spacecraft viewed the planet 28.62° to the west because Mars had rotated underneath it. In effect, it

245-432: Is capable of producing a sizable debris disk in Martian orbit, on the order of 5×10 kg, with a significant fraction of the material remaining close to Mars. This figure lies within the estimated mass range necessary to form the two moons, as other data suggests that only 1% of the mass of an accretion disk successfully forms moons. There are several other large impact basins on Mars that could have ejected enough debris to form

280-473: Is easy to spot on large maps of Mars. The crater was named in 1973 in honour of Mikhail V. Lomonosov . The impact that created the crater has been identified as a possible source of tsunami waves which washed the shores of an ancient ocean formerly present in the basin Vastitas Borealis . In July 2019, further support was reported for an ancient ocean on Mars that may have been formed by

315-589: Is the one in Nanedi Valles . Another was found in Nirgal Vallis . On 6 December 2006 NASA released photos of two craters in Terra Sirenum and Centauri Montes which appear to show the presence of flowing water on Mars at some point between 1999 and 2001. The pictures were produced by Mars Global Surveyor and are quite possibly the spacecraft's final contribution to our knowledge of Mars and

350-768: The Tharsis bulge along its rim. There is evidence for a secondary rim as well. This would make the North Polar Basin by far the largest impact crater in the Solar System , approximately four times the diameter of the next largest craters: Utopia Planitia , which is imbedded inside the North Polar Basin, the South Pole–Aitken basin on the Moon , and Hellas Planitia on Mars's southern hemisphere. This impact would have resulted in significant crustal melting and

385-439: The propulsion module, houses its rocket engines and propellant tanks. The Mars Global Surveyor mission cost about $ 154 million to develop and build and $ 65 million to launch. Mission operations and data analysis cost approximately $ 20 million/year. Five scientific instruments flew aboard MGS: The spacecraft was launched from a smaller Delta II rocket, necessitating restrictions in spacecraft weight. In order to achieve

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420-454: The Martian lithosphere , and the unusually low density and high porosity of Phobos, such that the moon would not be expected to remain aggregate if dynamically captured, suggest that the moons could have formed via accretion in Martian orbit, similar to how Earth's Moon formed. While estimates of the mass ejected by a large, Borealis-size impact vary, simulations suggest that a body approximately 0.02 Mars masses (~0.002 Earth Masses) in size

455-486: The amazing flow of scientific observations from Mars Global Surveyor is over." On 13 April 2007, NASA announced the loss of the spacecraft was caused by a flaw in a parameter update to the spacecraft's system software. The spacecraft was designed to hold two identical copies of the system software for redundancy and error checking. Subsequent updates to the software encountered a human error when two independent operators updated separate copies with differing parameters. This

490-402: The atmosphere over a range of times rather than the anticipated fixed times of 0200 and 1400, as well as collect data during three close encounters with Phobos. Finally, from November 1998 to March 1999, aerobraking resumed and shrank the high point of the orbit down to 450 km (280 mi). At this altitude, MGS circled Mars once every two hours. Aerobraking was scheduled to terminate at

525-551: The deposits are inconsistent with the volcanic and glacial hypotheses. One recent investigation identified three impact craters in Acidalia Planitia as being the likely source of the hypothetical tsunamis, with the Lomonosov crater (pictured right) being the most likely candidate. Here, the tsunami generated by the impactor would have reached heights of 75 m (250 ft), and traveled 150 km (90 mi) past

560-569: The moons of Mars. In 1998 it imaged what was later called the Phobos monolith , found in MOC Image 55103. After analyzing hundreds of high-resolution pictures of the Martian surface taken by the spacecraft, a team of researchers found that weathering and winds on the planet create landforms, especially sand dunes, remarkably similar to those in some deserts on Earth. Other discoveries from this mission are: Data from MGS have been used to perform

595-435: The moons. Analysis of Mars Global Surveyor data found mineral deposits similar to terminal moraines on Earth along the southern rim of the northern lowlands. Scientists have developed several theories to explain their presence, including: volcanic activity, glacial activity, and a series of Martian tsunamis . The arrangement of the deposits resembles deposits observed in recent tsunami events on Earth , and other features of

630-454: The near-circular orbit required for the mission while conserving propellant, the team designed a series of aerobraking maneuvers. Aerobraking had been successfully attempted by the Magellan mission at Venus , but the first complete test of the new procedure was to be carried out by MGS. Initially, MGS was placed in a highly elliptical orbit that took 45 hours to complete. The orbit had

665-482: The northern hemisphere could be explained by such an impact, as the shock waves produced might have demagnetized the crust. However, some authors have instead argued that the inverse is more likely to be true, and that rather than the North Polar Basin being an impact basin, the Southern Hemisphere of Mars may have actually the site of the impact instead, and the thickness of the Southern Hemisphere crust

700-620: The question of whether water exists on the planet. Lomonosov (Martian crater) Lomonosov is a crater on Mars , with a diameter close to 150 km. It is located in the Martian northern plains . Since it is large and found close (64.9° north) to the boundary between the Mare Acidalium quadrangle and the Mare Boreum quadrangle , it is found on both maps. The topography is smooth and young in this area, hence Lomonosov

735-527: The same time the orbit drifted into its proper position with respect to the Sun. In the desired orientation for mapping operations, the spacecraft always crossed the day-side equator at 14:00 (local Mars time) moving from south to north. This geometry was selected to enhance the total quality of the science return. The spacecraft circled Mars once every 117.65 minutes at an average altitude of 378 km (235 mi). The nearly polar orbit (inclination = 93°) which

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770-485: The southern rim. Dating techniques put the origin of the deposits sometime between the Late Hesperian and Early Amazonian periods, some 3 billion years ago, providing evidence to the presence of an ocean during this period. Mars Global Surveyor Mars Global Surveyor ( MGS ) was an American robotic space probe developed by NASA 's Jet Propulsion Laboratory and launched November 1996. MGS

805-473: The spacecraft had entered safe mode and was awaiting further instructions. On 21 and 22 November 2006, MGS failed to relay communications to the Opportunity rover on the surface of Mars. In response to this complication, Mars Exploration Program manager Fuk Li stated, "Realistically, we have run through the most likely possibilities for re-establishing communication, and we are facing the likelihood that

840-492: The spacecraft left or right from its ground track to shoot images as much as 30° from nadir. It was possible for a pitch maneuver to be added to compensate for the relative motion between the spacecraft and the planet. This was called a CPROTO (Compensation Pitch Roll Targeting Opportunity), and allowed for some very high resolution imaging by the onboard MOC (Mars Orbiting Camera). In addition to this, MGS could shoot pictures of other orbiting bodies, such as other spacecraft and

875-399: The spacecraft slowed down because of atmospheric resistance. This slowing caused the spacecraft to lose altitude on its next pass through the orbit's apoapsis. MGS had planned to use this aerobraking technique over a period of four months to lower the high point of its orbit from 54,000 km (33,554 mi) to altitudes near 450 km (280 mi). About one month into the mission, it

910-428: The time of launch, the spacecraft weighed 1,030.5 kg (2,272 lb). Most of its mass lies in the box-shaped module occupying the center portion of the spacecraft. This center module is made of two smaller rectangular modules stacked on top of each other, one of which is called the equipment module and holds the spacecraft's electronics, science instruments , and the 1750A mission computer. The other module, called

945-503: Was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program , Mars Global Surveyor performed atmospheric monitoring for sister orbiters during aerobraking , and helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry. It completed its primary mission in January 2001 and

980-541: Was always 14:00 for MGS as it moved from one time zone to the next exactly as fast as the Sun. After seven sols and 88 orbits, the spacecraft would approximately retrace its previous path, with an offset of 59 km to the east. This ensured eventual full coverage of the entire surface. In its extended mission, MGS did much more than study the planet directly beneath it. It commonly performed rolls and pitches to acquire images off its nadir track. The roll maneuvers, called ROTOs (Roll Only Targeting Opportunities), rolled

1015-412: Was as a result of impact-induced crust production. The origin of Mars' moons , Phobos and Deimos (pictured right), is unknown and remains controversial. One theory is that the moons are captured asteroids. However, the moons' near circular orbits and low inclination relative to the Martian equator are not in agreement with the capture hypothesis. The detection of minerals on Phobos similar to those in

1050-469: Was discovered that air pressure from the planet's atmosphere caused one of the spacecraft's two solar panels to bend backwards. The panel in question had incurred a small amount of damage shortly after launch, the extent of which did not become apparent until subjected to atmospheric forces. MGS had to be raised out of the atmosphere to prevent further damage to the solar panel and a new mission plan had to be developed. From May to November 1998, aerobraking

1085-645: Was expected to crash onto the surface of the planet at some point after about 2047 at the time of its original launch, having by then spent fifty years orbiting the red planet. This is to prevent contamination of the Martian surface with any germs that may be stuck to the spacecraft. The spacecraft, fabricated at the Lockheed Martin Astronautics plant in Denver, is a rectangular-shaped box with wing-like projections ( solar panels ) extending from opposite sides. When fully loaded with propellant at

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1120-422: Was expected to crash onto the surface of the planet in 2050. Mars Global Surveyor achieved the following science objectives during its primary mission: Mars Global Surveyor also achieved the following goals of its extended mission: On 2 November 2006, NASA lost contact with the spacecraft after commanding it to adjust its solar panels. Several days passed before a faint signal was received indicating that

1155-429: Was followed by a corrective update that unknowingly included a memory fault which resulted in the loss of the spacecraft. Originally, the spacecraft was intended to observe Mars for 1 Martian year (approximately 2 Earth years ). However, based on the vast amount of valuable science data returned, NASA extended the mission three times. MGS remains in a stable near-polar circular orbit at about 450 km altitude, and

1190-441: Was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode . Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007. MGS remains in a stable near-polar circular orbit at about 450 km altitude and as of 1996,

1225-464: Was temporarily suspended to allow the orbit to drift into the proper position with respect to the Sun and enable optimal use of the solar panels. Although data collection during aerobraking was not in the original mission plan, all science instruments remained functional and acquired vast amounts of data during this "unexpected bonus period of observation". The team was able to evaluate more information about

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