Exploration of Mars
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The exploration of Mars has been an important part of the space exploration programs of the Soviet Union (later Russia), the United States, Europe, and Japan. Dozens of robotic spacecraft, including orbiters, landers, and rovers, have been launched toward Mars since the 1960s. These missions were aimed at gathering data about current conditions and answering questions about the history of Mars. The questions raised by the scientific community are expected to not only give a better appreciation of the red planet but also yield further insight into the past, and possible future of Earth.
The exploration of Mars has come at a considerable financial cost with roughly two-thirds of all spacecraft destined for Mars failing before completing their missions, with some failing before they even begin. Such a high failure rate can be attributed to the complexity and large number of variables involved in an interplanetary journey, and has led researchers to jokingly speak of The Great Galactic Ghoul [1] which subsists on a diet of Mars probes. This phenomenon is also informally known as the Mars Curse. [2]
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[edit] The Planet Mars
Mars has long been the subject of human fascination. Early telescopic observations revealed color changes on the surface which were originally attributed to seasonal vegetation as well as linear features which were ascribed to intelligent design. These early and erroneous interpretations led to widespread public interest in Mars. Further telescopic observations found Mars' two moons - Phobos and Deimos, dry channels and depressions, polar ice caps, Olympus Mons, the solar system's tallest mountain, and Valles Marineris, the solar system's largest canyon system. These discoveries have only piqued further interest in the study and exploration of the red planet. Mars is a rocky planet, like Earth, that formed around the same time, yet with only half the diameter of Earth, and a far thinner atmosphere, it has a cold and desert-like surface. (It is notable, however, that although the planet has only one quarter of the surface area of the Earth, it has about the same land area, since only one quarter of the surface area of the Earth is land).
[edit] Launch windows
In order to understand the history of the robotic exploration of Mars it is important to note that minimum-energy launch windows occur at intervals of 2.135 years, i.e. 780 days (the planet's synodic period) with respect to Earth. This is a consequence of the Hohmann transfer orbit for minimum-energy interplanetary transfer. Launch windows were / will be in:
- November to December 1996
- December 1998 to January 1999
- April 2001
- June to July 2003
- August 2005
- October 2007
- December 2009
- February 2012
Like the outbound launch windows, minimum energy inbound (Mars to Earth) launch windows also occur at intervals of 780 (Earth) days.
In addition to these minimum-energy trajectories, which occur when the planets are aligned so that the Earth to Mars transfer trajectory goes halfway around the sun, an alternate trajectory which has been proposed goes first inward toward Venus orbit, and then outward, resulting in a longer trajectory which goes about 360 degrees around the sun ("conjunction-class trajectory"). Although this transfer orbit takes longer, and also requires more energy, it is sometimes proposed as a mission trajectory for human missions.
[edit] Early flyby probes and orbiters
[edit] Early Soviet missions
The Marsnik program, was the first Soviet unmanned spacecraft interplanetary exploration program, which consisted of two flyby probes launched towards Mars in October 1960, Marsnik 1 and 2 dubbed Mars 1960A and Mars 1960B (also known as Korabl 4 and Korabl 5 respectively). After launch, the third stage pumps on both Marsnik launchers were unable to develop enough thrust to commence ignition, so Earth parking orbit was not achieved. The spacecraft reached an altitude of 120 km before reentry.
Mars 1962A a Mars fly-by mission, launched on October 24, 1962 and Mars 1962B a lander mission, launched in late December of the same year both failed from either breaking up as they were going into Earth orbit or having the upper stage explode in orbit during the burn to put the spacecraft into the Mars trajectory.
Mars 1 (1962 Beta Nu 1) an automatic interplanetary station launched to Mars on November 1, 1962 was the first probe of the Soviet Mars probe program. Mars 1 was intended to fly by the planet at a distance of about 11,000 km and take images of the surface as well as send back data on cosmic radiation, micrometeoroid impacts and Mars' magnetic field, radiation environment, atmospheric structure, and possible organic compounds. Sixty-one radio transmissions were held, initially at two day intervals and later at 5 days in which a large amount of interplanetary data was collected. On 21 March 1963, when the spacecraft was at a distance of 106,760,000 km from Earth, on its way to Mars, communications ceased, due to failure of the spacecraft's antenna orientation system.
In 1964, both Soviet probe launches, of Zond 1964A on June 4, and Zond 2 on November 30, (part of the Zond program), resulted in failures. Zond 1964A had a failure at launch, while communication was lost with Zond 2 en route to Mars after a mid-course maneuver, in early May 1965.
[edit] Mariner program
In 1964, NASA's Jet Propulsion Laboratory made two attempts at reaching Mars. Mariner 3 and Mariner 4 were identical spacecraft designed to carry out the first flybys of Mars. Mariner 3 was launched on November 5, 1964, but the shroud encasing the spacecraft atop its rocket failed to open properly, and it failed to reach Mars. Three weeks later, on November 28, 1964, Mariner 4 was launched successfully on an eight-month voyage to the red planet.
Mariner 4 flew past Mars on July 14, 1965, providing the first close-up photographs of another planet. The pictures, gradually played back to Earth from a small tape recorder on the probe, showed lunar-type impact craters.
NASA continued the Mariner program with another pair of Mars flyby probes, Mariner 6 and 7, at the next launch window. These probes reached the planet in 1969. During the following launch window the Mariner program again suffered the loss of one of a pair of probes. Mariner 9 successfully entered orbit about Mars, the first spacecraft ever to do so, after the launch time failure of its sister ship, Mariner 8. When Mariner 9 reached Mars, it and two Soviet orbiters (Mars 2 and Mars 3, see Mars probe program below) found that a planet-wide dust storm was in progress. The mission controllers used the time spent waiting for the storm to clear to have the probe rendezvous with, and photograph, Phobos. When the storm cleared sufficiently for Mars' surface to be photographed by Mariner 9, the pictures returned represented a substantial advance over previous missions. These pictures were the first to offer evidence that liquid water might at one time have flowed on the planetary surface.
[edit] Surface missions
The following is a map of landings on Mars. (When viewing this page on-line, the Mars lander icons will link to the corresponding articles.) Template:Mars Map Landers
[edit] Mars Curse
The high failure rate of missions launched from Earth attempting to explore Mars has become informally known as the Mars Curse. See below for a full list of launch attempts to Mars.
As of the end of 2006, of 37 launches from Earth in an attempt to reach the planet, only 18 succeeded, a success rate of under 50%. Eleven of the missions included attempts to land on the surface, but only six transmitted data once after landing. Some suggest, mostly in jest, that there is actually some force trying to prevent or punish the exploration of Mars. The Galactic Ghoul is a fictional space monster that consumes Mars probes, a term coined in 1997 by Time Magazine journalist Donald Neff.[3][4][5]
The U.S. (NASA) Mars exploration program has had a somewhat better record of success in Mars exploration, achieving success in 12 out of 17 missions launched (about 71% success rate), and succeeding in five out of six of the launches of Mars landers.
[edit] Manned missions
Many people have long advocated a manned mission to Mars as the next logical step for a manned space program after lunar exploration. Aside from the prestige such a mission would bring, advocates argue that humans would be easily able to outperform robotic explorers, justifying the expenses. Critics contend, however, that robots can perform better than humans at a fraction of the expense.
[edit] Timeline of Mars exploration
[edit] Cancelled missions
- Voyager - 1970s - Two orbiters and two landers, launched by a single Saturn V rocket.
- Mars Aerostat - Russian/French balloon mission[7], originally planned for the 1992 launch window, postponed to 1994 and then to 1996 before being cancelled [8].
- Mars-98 - Russian mission including an orbiter, lander, and rover, planned for 1998 launch opportunity
- Mars Surveyor 2001 Lander - October 2001 - Mars lander
- NetLander - 2007 or 2009 - Mars netlanders
- Mars Telecommunications Orbiter - September 2009 - Mars orbiter for telecommunications
- Wright Flyer Mars airplane micromission, proposed for December 17, 2003, the centennial of the Wright brother's first flight.
[edit] Mars Science Questions
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Among the questions asked by scientists are the following:
- How does the composition of Mars differ from the Earth's and how have the two planets evolved differently?
- How does the composition and state of the interior of Mars differ from the Earth's?
- Is Mars still geologically active?
- Does Mars have a liquid core?
- What natural resources are available at the surface for future human use?
- Was there an early dense atmosphere on Mars?
- How did Mars lose its atmosphere?
- Did Mars once have oceans?
- What changes in climate has Mars experienced over its geologic history and what caused those changes?
- How stable is the climate of Mars today?
- Did chemical evolution take place on Mars, leading to the formation of prebiotic organic molecules?
- Did chemical evolution lead to the formation of replicating molecules, i.e. life?
- If life once arose, is it to be found anywhere on Mars today?
- How did Phobos and Deimos come to be where they are? What geology and resources do they possess?
[edit] See also
- Atmospheric reentry
- List of artificial objects on Mars
- Mars Scout Program
- Space colonization
- New Frontiers Program
- Space weather
[edit] Further reading
- Mars - A Warmer, Wetter Planet by Jeffrey S. Kargel (published July 2004; ISBN 978-1-85233-568-7)
- The Compact NASA Atlas of the Solar System by Ronald Greeley and Raymond Batson (published January 2002; ISBN 0-5218-0633-X)
[edit] References
- ^ Dinerman, Taylor (September 27, 2004). Is the Great Galactic Ghoul losing his appetite?. The space review. Retrieved on 2007-03-27.
- ^ Knight, Matthew. Beating the curse of Mars. Science & Space. Retrieved on 2007-03-27.
- ^ "The Depths of Space: The Story of the Pioneer Planetary Probes (2004)" from The National Academies Press. URL accessed April 7, 2006.
- ^ "Uncovering the Secrets of Mars" (first paragraph only). Time July 14, 1997 Vol. 150 No. 2. URL accessed April 7, 2006.
- ^ Matthews, John & Caitlin. "The Element Encyclopedia of Magical Creatures",Barnes & Noble Publishing, 2005. ISBN 0-7607-7885-X
- ↑ a b "The First Rover on Mars - The Soviets Did It in 1971" The Planetary Report July/August 1990 issue. URL accessed March 30, 2006.
- ^ C. Tarrieu, "Status of the Mars 96 Aerostat Development", Paper IAF-93-Q.3.399, 44th Congress of the International Astronautical Federation, 1993.
- ^ P.B. de Selding, "Planned French Balloon May Be Dropped", Space News, 17-23 April 1995, pp. 1, 20
[edit] External links
- MarsDrive Consortium Reference Mission Design and Mars Advocacy
- WhatOnMars Latest Mars News & Images
- Mars Odyssey News Constellation Program news
- marsgeo.com Mars rover videos, photos, detailed analysis of surface geology
- space.com Mars Rovers site
- Explore Mars Now Interactive Mars base simulation. Winner of 2003 Webby Award for Science.
- Next on Mars (Bruce Moomaw, Space Daily, 9 March 2005): An extensive overview of NASA's Mars exploration plans
- Mars Exploration Program Analysis Group at Jet Propulsion Laboratory
- Catalog of Soviet Mars images Collection of Russian mars-probe images.
- Mars balloon
- NASA History Series Publications (many of which are on-line)
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