Mars landing
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A Mars landing is when a spacecraft lands on the surface of Mars. There have been many Mars landings, all of which as of May 23rd, 2008 have been unmanned.
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[edit] Unmanned landings
[edit] Mars probe program
In 1969, the Soviet Union prepared a 5-ton orbiter called M-69. Two copies of the probe were lost in launch related complications caused by problems with the newly developed Proton rockets [1].
In 1971, shortly after the Cosmos 419 probe was lost in the fourth stage of the launch due to issues concerning the failure in the separation of Cosmos' payload from the launch vehicle[2], the Soviet Union successfully sent probes Mars 2 and Mars 3, as part of the Mars probe program. The Mars 2 and 3 probes each carried a lander, both of which failed upon landing. They were the first human artifacts to touch down on Mars. Mars 3 lander however, still managed to transmit a portion of the first picture from Martian surface.
The Mars 2 and 3 orbiters sent back a large volume of data covering the period from December 1971 to March 1972, although transmissions continued through to August. By 22 August 1972, after sending back data and a total of 60 pictures, Mars 2 and 3 concluded their missions. The images and data enabled creation of surface relief maps, and gave information on the Martian gravity and magnetic fields[3].
In 1973, the Soviet Union sent four more probes to Mars: the Mars 4 and Mars 5 orbiters and the Mars 6 and Mars 7 fly-by/lander combinations. All missions except Mars 7 sent back data, with Mars 5 being most successful. Mars 5 transmitted 60 images before a loss of pressurization in the transmitter housing, ended the mission. Mars 6 lander transmitted data during descent, but failed upon impact. Mars 4 flew by the planet at a range of 2200 km returning one swath of pictures and radio occultation data, which constituted the first detection of the nightside ionosphere on Mars [4]. Mars 7 probe separated prematurely from the carrying vehicle due to a problem in the operation of one of the onboard systems (altitude control or retro-rockets) and missed the planet by 1300 km.
[edit] Viking program
In 1976 the two Viking probes entered orbit about Mars and each released a lander module that made a successful soft landing on the planet's surface. The two missions returned the first color pictures and extensive scientific information. Measured temperatures at the landing sites ranged from 150 to 250 K, with a variation over a given day of 35 to 50 K. Seasonal dust storms, pressure changes, and movement of atmospheric gases between the polar caps were observed. A biology experiment produced possible evidence of life, but it was not corroborated by other on-board experiments.
While searching for a suitable landing spot for Viking 2's lander, the Viking 1 orbiter photographed the landform that constitutes the so-called "Face on Mars" on July 25, 1976.
The Viking program was a descendant of the cancelled Voyager program, whose name was later reused for a pair of outer solar system probes.
[edit] Phobos program
Two Soviet probes were sent to Mars in 1988 as part of the Phobos program. Phobos 1 operated nominally until an expected communications session on 2 September 1988 failed to occur. The problem was traced to a software error, which deactivated altitude thrusters causing the spacecrafts' solar arrays to no longer point at the Sun, depleting Phobos 1 batteries. Phobos 2 operated nominally throughout its cruise and Mars orbital insertion phases on January 29, 1989, gathering data on the Sun, interplanetary medium, Mars, and Phobos. Shortly before the final phase of the mission, during which the spacecraft was to approach within 50 m of Phobos' surface and release two landers, one a mobile 'hopper', the other a stationary platform, contact with Phobos 2 was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on March 27, 1989. The cause of the failure was determined to be a malfunction of the on-board computer.
[edit] Mars Global Surveyor
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After the 1992 failure of NASA's Mars Observer orbiter, NASA retooled and launched Mars Global Surveyor. This mission was the first successful United States mission, and the first fully successful mission overall, to the red planet in two decades when it launched November 7, 1996, and entered orbit on September 12, 1997. After a year and a half trimming its orbit from a looping ellipse to a circular track around the planet, the spacecraft began its primary mapping mission in March 1999. It has observed the planet from a low-altitude, nearly polar orbit over the course of one complete Martian year, the equivalent of nearly two Earth years. Mars Global Surveyor completed its primary mission on January 31, 2001, and completed several extended mission phases.
The mission has studied the entire Martian surface, atmosphere, and interior, and has returned more data about the red planet than all other Mars missions combined. These valuable data are archived and available publicly.[5]
Among key scientific findings so far, 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. Similar channels on Earth are formed by flowing water, but on Mars the temperature is normally too cold and the atmosphere too thin to sustain liquid water. Nevertheless, many scientists hypothesize that liquid groundwater can sometimes surface on Mars, erode gullies and channels, and pool at the bottom before freezing and evaporating.
Magnetometer readings show that the planet's magnetic field is not globally generated in the planet's core, but is localized in particular areas of the crust. New temperature data and closeup images of the Martian moon Phobos show its surface is composed of powdery material at least 1 metre (3 feet) thick, caused by millions of years of meteoroid impacts. Data from the spacecraft's laser altimeter have given scientists their first 3-D views of Mars' north polar ice cap.
On the November 5, 2006 MGS lost contact with Earth and hasn't been heard from since.[6]
[edit] Mars Pathfinder
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The Mars Pathfinder spacecraft, launched one month after Global Surveyor, landed on July 4, 1997. Its landing site was an ancient flood plain in Mars' northern hemisphere called Ares Vallis, which is among the rockiest parts of Mars. It carried a tiny remote-controlled rover called Sojourner, which traveled a few meters around the landing site, exploring the conditions and sampling rocks around it. Newspapers around the world carried images of the lander dispatching the rover to explore the surface of Mars in a way never achieved before.
Until the final data transmission on September 27, 1997, Mars Pathfinder returned 16,500 images from the lander and 550 images from the rover, as well as more than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors. Findings from the investigations carried out by scientific instruments on both the lander and the rover suggest that Mars was at one time in its past warm and wet, with water existing in its liquid state and a thicker atmosphere. The mission website was the most heavily-trafficked up to that time.
[edit] Spate of failures
Mars 96, an orbiter launched on November 16, 1996 by Russia failed, when the planned second burn of the Block D-2 fourth stage did not occur.
Following the success of Global Surveyor and Pathfinder, another spate of failures occurred in 1998 and 1999, with the Japanese Nozomi orbiter and NASA's Mars Climate Orbiter, Mars Polar Lander, and Deep Space 2 penetrators all suffering various fatal errors. Mars Climate Orbiter is infamous for Lockheed Martin engineers mixing up the usage of imperial units with metric units, causing the orbiter to burn up while entering Mars' atmosphere.
[edit] Mars Odyssey
In 2001 the run of bad luck ended when NASA's Mars Odyssey orbiter arrived. Its mission is to use spectrometers and imagers to hunt for evidence of past or present water and volcanic activity on Mars. In 2002, it was announced that the probe's gamma ray spectrometer and neutron spectrometer had detected large amounts of hydrogen, indicating that there are vast deposits of water ice in the upper three meters of Mars' soil within 60° latitude of the south pole.
[edit] Mars Express and Beagle 2
On June 2, 2003, the European Space Agency's Mars Express set off from Baikonur Cosmodrome to Mars. The Mars Express craft consists of the Mars Express Orbiter and the lander Beagle 2. Although the landing probe was not designed to move, it carried a digging device and the smallest mass spectrometer created to date, as well as a range of other devices, on a robotic arm in order to accurately analyse soil beneath the dusty surface.
The orbiter entered Mars orbit on December 25, 2003, and Beagle 2 entered Mars' atmosphere the same day. However, attempts to contact the lander failed. Communications attempts continued throughout January, but Beagle 2 was declared lost in mid-February, and a joint inquiry was launched by the UK and ESA. Nevertheless, Mars Express Orbiter confirmed the presence of water ice and carbon dioxide ice at the planet's south pole. NASA had previously confirmed their presence at the north pole of Mars.
[edit] Mars Exploration Rovers
Shortly after the launch of Mars Express, NASA sent a pair of twin rovers toward the planet as part of the Mars Exploration Rover Mission. On 10 June 2003, NASA's MER-A (Spirit) Mars Exploration Rover was launched. It successfully landed in Gusev Crater (believed once to have been a crater lake) on 3 January 2004. It examined rock and soil for evidence of the area's history of water. On July 7, 2003, a second rover, MER-B (Opportunity) was launched. It landed on 24 January 2004 in Meridiani Planum (where there are large deposits of hematite, indicating the presence of past water) to carry out similar geological work.
Despite a temporary loss of communication with the Spirit Rover (caused by too many files being stored in its flash memory[1]) delaying exploration for several days, both rovers eventually began exploring their landing sites. The rover Opportunity landed in a particularly interesting spot, a crater with bedrock outcroppings. In fast succession mission team members announced on 2 March that data returned from the rover showed that these rocks were once "drenched in water", and on 23 March that it was concluded that they were laid down underwater in a salty sea. This represented the first strong direct evidence for liquid water being on Mars at some time in the past.
Towards the end of July 2005, it was reported by the Sunday Times that the rovers may have carried the bacteria Bacillus safensis to Mars. According to one NASA microbiologist, this bacteria could survive both the trip and conditions on Mars. A book containing this claim, Out of Eden by Alan Burdick, is due to be published in the United Kingdom. Despite efforts to sterilise both landers, neither could be assured to be completely sterile.[7]
Having only been designed for three month missions, both rovers are still operating as of April 2008, but Spirit and Opportunity are starting to show their age. These rovers have discovered new things, including Heat Shield Rock, the first meteorite to be discovered on another planet.
[edit] Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a multipurpose spacecraft designed to conduct reconnaissance and exploration of Mars from orbit. The $720 million USD spacecraft was built by Lockheed Martin under the supervision of the Jet Propulsion Laboratory, launched August 12, 2005, and attained Martian orbit on March 10, 2006.
The MRO contains a host of scientific instruments such as the HiRISE camera, CRISM, and SHARAD. The HiRISE camera is used to analyze Martian landforms, whereas CRISM and SHARAD can detect water, ice, and minerals on and below the surface. Additionally, MRO is paving the way for upcoming generations of spacecraft through daily monitoring of Martian weather and surface conditions, searching for future landing sites, and testing a new telecommunications system that will enable the orbiter to send and receive information at an unprecedented bitrate. Data transfer to and from the spacecraft will occur faster than all previous interplanetary missions combined and allowing it to serve as an important relay satellite for future missions.
[edit] Rosetta and Dawn
The ESA Rosetta space probe mission to the comet 67P/Churyumov-Gerasimenko flew within 250 km of Mars on February 25, 2007 in a gravitational slingshot designed to slow and redirect the spacecraft.[8] The NASA Dawn spacecraft will also use the gravity of Mars to change direction and velocity, and will briefly do a little science in conjunction with the many probes already there. Dawn is scheduled to pass the red planet in 2009.
[edit] Phoenix Lander
Being the latest mission to Mars, Phoenix launched on August 4, 2007, and touched down on the northern polar region of Mars on May 25, 2008. It is famous for having been successfully photographed while landing, since this was the first time one spacecraft captured the landing of another spacecraft onto a planetary body[9] (the Moon not being a planet, but a satellite).
[edit] Future Missions
Phoenix will be followed with an expected launch in 2009 of the Mars Science Laboratory, a rover more capable than Spirit and Opportunity.
Russia is still planning to launch Phobos-Grunt, a sample return mission to Phobos, with the joint Chinese Yinghuo-1 Mars orbiter in 2009. The ESA Beagle 2: Evolution mission is also planned for 2009.
A second Scout mission, Mars Scout should be selected for 2013. The Mars Science and Telecommunications Orbiter as well is planned for 2013 [10]. In addition, NASA plans to launch a proposed rover, the Astrobiology Field Laboratory in 2016.
The ExoMars mission is planned for 2014. ExoMars should obtain soil samples from up to 2 meters depth and make an extensive search for organic and biochemical substances.
In the far future there's the proposed Mars Sample Return Mission, but this has been delayed until at least 2016, and more probably to 2024. This mission, a collaboration between ESA and NASA, is part of the Aurora Programme.
[edit] References
- ^ NASA A Chronology of Mars Exploration. Retrieved on 2007-03-28.
- ^ NASA (NSSDC) Master Catalog Display Cosmos 419. Retrieved on 2007-03-28.
- ^ NASA (NSSDC) Master Catalog Display Mars 3. Retrieved on 2007-03-28.
- ^ NASA (NSSDC) Master Catalog Display Mars 4. Retrieved on 2007-03-28.
- ^ PDS Geosciences Node Data and Services: MGS. Retrieved on 2006-08-27.
- ^ Leonard David. Mars Global Surveyor Remains Silent, Feared Lost. Retrieved on 2007-04-01.
- ^ "It's one small step for a bug, a giant red face for NASA", The Sunday Times (UK). Retrieved on 2006-06-17.
- ^ Europe set for billion-euro gamble with comet-chasing probe. PhysOrg.com.
- ^ "Phoenix Makes a Grand Entrance", NASA. Retrieved on 2008-05-27.
- ^ "NASA MEPAG: Mars Science and Telecommunications Orbiter (DRAFT)", NASA. Retrieved on 2006-06-19.
[edit] See also
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