Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Mars Science Laboratory
From Wikipedia, the free encyclopedia
 |
This article or section contains information regarding a future spaceflight. Due to the nature of the content, details may change dramatically as the launch date approaches and/or more information becomes available. |
 |
The Mars Science Laboratory (or MSL for short) is a NASA rover scheduled to launch in December 2009 and perform a precision landing on Mars in October 2010. This rover will be three times as heavy and twice the width of the Mars Exploration Rovers (MERs) that landed in 2004. It will carry more advanced scientific instruments than any other mission to Mars. The international community will provide some of these instruments. The MSL rover will be launched by an Atlas V 541. Once on the ground, MSL will analyze dozens of samples scooped up from the soil and drilled powders from rocks. MSL will be expected to operate for at least 1 martian year (~2 Earth years) as it explores with greater range than any previous Mars rover. It will investigate the past or present ability of Mars to support life.
Contents |
In September 2006 MSL was approved by NASA HQ for a 2009 launch. Several JPL engineers working on MSL have informally stated that the MSL design will likely be used on future rovers after the first MSL is launched in 2009.
MSL is expected to weigh over 800 kg (1,760 lb) including 65 kg (143 lb) of scientific instruments, compared to the MERs which weigh 185 kg including 5 kg of scientific instruments. MSL will be able to roll over obstacles approaching 75 cm in height. Maximum terrain-traverse speed is estimated to be 90 m per hour via automatic navigation, however, average traverse speeds will likely be 30 m/h, based on variables including power levels, difficulty of the terrain, slippage, and visibility. MSL is expected to traverse a minimum of 6 km in its 2 year mission, perhaps further with extended mission time.
At present 10 instruments have been selected for development or production for MSL:
All cameras are being developed by Malin Space Science Systems; all share common design components such as on-board electronic imaging processing boxes and 1600x1200 color CCDs.
- MastCam: This system will provide multiple spectra and true color imaging with two-camera stereoscopic (three-dimensional) vision. True-color are at 1200x1200 pixels and up to 10 frames per second hardware-compressed, high-definition video at 1280x720. For comparison the MER panoramic camera can only produce 1024x1024 black&white images. The same filter wheel design for multiple spectra images from MER will be used on MastCam. Both cameras will have mechanical zoom and can image objects as far away as 1 km at a resolution of 10 cm per pixel.
- Mars Hand Lens Imager (MAHLI): This system will consist of a camera mounted to a robotic arm on the rover. It will be used to acquire microscopic images of rock and soil, like the microscopic imager (MI) on MER. Unlike the MI, MAHLI will take true color images at 1600x1200 pixels with a resolution as high as 12.5 micrometers per pixel. MAHLI will have both white and UV LED illumination for imaging in darkness or imaging fluorescence. MAHLI will also have mechanical focusing in a range from infinite to mm distances.
- MSL Mars Descent Imager (MARDI): During the descent to the Martian surface MARDI will take approximately 500 color images at 1600x1200 pixels starting at distances of about 3.7 km to near 5 meters from the ground. MARDI imaging will allow the mapping of surrounding terrain and location of landing.
ChemCam is a remote LIBS system that can target a rock from up to 13 meters away, vaporizing a small amount of the underlying mineral and then collecting a spectrum of the light emitted by the vaporized rock by using a micro-imaging camera with a field of view of 80 microradians. It is being developed by the Los Alamos National Laboratory and the French CESR laboratory (in charge of the laser). A infrared laser with 1067 nm wavelength and a 5 ns pulse will focus on a spot with 1 GW/cm² resulting in 30 mJ energy, the detection will be done between 240 nm and 800 nm.[1] [2]
This device will irradiate samples with alpha particles and map the spectra of X-rays that are reemitted. It is being developed by the Canadian Space Agency for determining the elemental composition of samples. The APXS is a form of PIXE. Similar instruments have been part of Mars Pathfinder and the Mars Exploration Rovers.[3]
Chemin stands for "Chemistry & Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument". Chemin is a X-ray diffraction/X-ray fluorescence instrument that will quantify minerals and mineral structure of samples. It is being developed by the NASA Jet Propulsion Laboratory.[4]
Consisting of a gas chromatograph mass spectrometer and laser spectrometer, the SAM instrument suite will analyze organics and gases from both atmospheric and solid samples. It is being developed by the NASA Goddard Space Flight Center and Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA).[5]
This instrument will characterize the broad spectrum of radiation found near the surface of Mars for purposes of determining the viability and shielding needs for human explorers. Funded by the Exploration Systems Mission Directorate at NASA Headquarters and developed by Southwestern Research Institute (SwRI).
A pulsed neutron source and detector for measuring hydrogen or ice and water at or near the martian surface, provided by the Russian Federal Space Agency.
Meteorological package and an ultraviolet sensor provided by the Spanish Ministry of Education and Science. It will be mounted on the camera mast and measure atmospheric pressure, humidity, wind currents and direction, air and ground temperature and ultraviolet radiation levels.
The rover will have the same type of engineering cameras that the MER rovers had, a stereo pair of Navcams used to select safe routes for driving and a set of front and rear stereo-pair Hazcams used for autonomous hazard avoidance during rover drives and for safe positioning of the robotic arm on rocks and soils.
The rover will probably be powered by radioisotope thermoelectric generators (RTGs). Solar power is not an efficient power source for Mars surface operations and was only used on Mars Pathfinder and MER because of politically imposed flight restrictions on RTGs. Solar power systems cannot operate effectively at high Martian latitudes, in shaded areas, nor in dusty conditions. Furthermore, it cannot provide power at night, thus limiting the ability of the rover to keep its systems warm, reducing the life expectancy of electronics. RTGs can provide reliable, continuous power day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments. Even so, as of 2006 it states on the MSL home page that solar power is still an option under consideration.
The first successful Mars landers, Viking 1 and Viking 2 in 1976, were RTG-powered—the Viking 1 lander worked for six years on the Martian surface (ultimately failing due to faulty command sent by ground control that resulted in loss of contact). The proposed power plant will use "next generation" RTGs, either Boeing’s Multi-mission Radioisotope Thermoelectric Generator, which is a more flexible and compact power system under development and based on conventional RTGs, or Lockheed Martin’s Stirling Radioisotope Generator, which is more efficient but untested for use in space. Evidence points to the MMRTG being selected at this point, likely because of reliability and underdevelopment issues with the SRG.
MSL will be set down on the Martian surface using a new NASA high-precision entry, descent, and landing (EDL) system that will place it within ten kilometers of an intended target, in contrast to the 150-kilometer error of previous landing systems used on Mars. The rover is folded up within an aeroshell which protects it during the travel through space and during the entry at Mars. Much of the reduction of the landing precision error is accomplished by an atmospheric entry guidance algorithm, similar to that used by the astronauts returning to Earth in the Apollo space program. This guidance uses the lifting force experienced by the aeroshell to "fly out" any detected error in range and thereby arrive at the targeted landing site. In order for the aeroshell to have lift, its center of mass is offset from the axial centerline which results in an off-center trim angle in atmospheric flight, again similar to the Apollo Command Module. This is accomplished by a series of ejectable ballast mass. The lift vector is controlled by four sets of two Reaction Control System (RCS) thrusters that produce approximately 500 N of thrust per pair. This ability to change the pointing of the direction of lift allows the spacecraft to react to the ambient environment, and steer toward the landing zone.
After the entry phase is complete and the capsule has slowed to Mach 2 several kilometers over the ground, a supersonic parachute is deployed. The parachute is similar in design to that used by the Viking landers, Mars Pathfinder, and the Mars Exploration Rovers. The entry vehicle must first eject the ballast mass such that the center-of-gravity offset is removed and the velocity vector aligns with the parachute deployment vector. This prevents the spacecraft from experiencing a torque due to the pointing differences and increases the spacecraft's stability.
Following the parachute deployment, the rover and descent stage drop out of the aeroshell. A number of passive mechanisms are used to ensure a clean separation. The descent stage is a platform above the rover with variable thrust mono propellant hydrazine rocket thrusters (based on upgraded Viking heritage landing rockets) on arms extending around this platform to slow the descent. Meanwhile the rover itself is being transformed from its stowed flight configuration to a landing configuration while being lowered beneath the descent stage by the "sky crane" system. The descent stage contains the Bridle Umbilical Descent Rate Limiter (BUDrl) which is a next generation design based on MER heritage. This consists of 3 bridles lowering the rover itself and an umbilical cable carrying electrical signals between the descent stage and rover. At roughly 7.5 meters below the descent stage the sky crane system slows to a halt and the rover touches down.
After the rover touches down it waits 2 seconds to confirm that it is on solid ground and fires several pyros (small explosive devices) activating cable cutters on the bridle and umbilical cords to free itself from the descent stage. The descent stage promptly flies away to a crash landing, and the rover gets ready to roam Mars.
Early landing system proposals for the rover featured a "pallet" design (similar to that used for Mars Pathfinder and the Mars Exploration Rovers) with a liquid-fueled rocket thruster system to land the rover in the final seconds of descent. The pallet would have used airbags or a "crushable" design to permit a safe landing. Earlier designs also sometimes included a second parachute for subsonic speeds.
At the first MSL Landing Site workshop, 33 potential landing sites were identified.
| Name | Location | Elevation | Target |
|---|---|---|---|
| Nili Fossae Trough | ~22°N, ~75°E | -0.6 km | Phyllosilicates |
| Holden Crater Fan | 26.4°S, 325.3°E | -2.3 km | Layered Materials |
| Terby Crater | 28°S, 73°E | -5 km | Layered Material |
| Mawrth Vallis | 22.3°N, 343.5°E | ~-2 km | Phyllosilicates |
| Eberswalde Crater | 24.0°S, 326.3°E | -0.8 and -0.4 km | Delta |
| Gale Crater | 4.6°S, 137.2°E | -4.5 km | Interior Layered Deposits |
| Candor Chasma | Various | -4 km | Sulfate Deposits |
| North Meridiani Planum | 2.7°N, 358.8°E | -1.5 km | Sedimentary Layers |
| Juventae Chasma | 5°S, 297°E | -2 km | Layered Sulfates |
| Nilo Syrtis | ~23°N, ~76°E | ~-0.5 | Phyllosilicates |
| Melas Chasma | 9.8°S, 283.6°E | -1.9 km | Paleolake |
| East Meridiani Planum | 0°, 3.7°E | ~-1.3 km | Sedimentary Layers |
| Athabasca Vallis | 10°N, ?oE | -2.4 km | Cerberus Rupes Deposits |
| Iani Chaos | 2°S , ~342°E | Below -2 km | Hematite, Sulfate |
| Crater in Nili Fossae | 18.4°N, 77.68°E | -2.6 km | Valley Networks, layers |
| Eos Chasma | ~11°N, ~320°E | ~-4 km | Chert |
| Crater lake in Meridiani Planum | 5.6°N, 358°E | ~-1.5 km | Crater lake sediments |
| NE Syrtis Major | ~10°N, ~70°E | ~1 km | Volcanics |
| Basin in Margaritifer Terra | 12.77°S, 338.1°E | -2.12 km | Fluvial Deposits |
| Eastern Melas Chasma | 11.62°S, 290.45°E | Below-2 km | Interior Layered Deposits |
| Hellas Planitia/Dao Vallis | 40°S, 85°E | Below -2 km | A major valley |
| Xanthe Terra/Hypanis Vallis | 11°N, 314°E | Below -2 km | Delta |
| Becquerel Crater | 21.8°N, 351°E | -2.6 to -3.8 km | Layered Sedimentary Rocks |
| SW Arabia Terra | 2-12°N, 355-348°E | -1 km | Sed. Rocks, Methane |
| Gullies/Hale Crater | 35.7°S, 323.4°E | –2.4 km | Gullies |
| W. Arabia Terra | 8.9°N, 358.8°E | -1.2 km | Sedimentary Rocks |
| Argyre Planitia | 56.8oS, 317.7°E | -1.5 km | Glacial Features |
| NW Slope Valleys | ~0, 145°E | ~-2 km | Flood Features |
| Western Meridiani Planum | 1.8°S, 7.6°E | ~-1.0 to -1.5 km | Sediments, Hematite |
| Elysium Planitia/Avernus Colles | 1.0°S, 169.5°E | Below -2 km | High iron abundance |
| Meridiani Bench | 7.5°N, 354°E | ~-1 to –1.5 km | Layered Sediments |
| SML Craters | 49°S, 14°E | Above -0.5 km | Recent Climate Deposits |
| Isidis Planitia Escarpment | 5-15°N, 80-95°E | Below -2 km | Volatile sink |
It is possible NASA will adopt a plan to use multiple post-2011 MSLs to chemically sample, select, and haul rock samples to sample return "Mars ascent vehicles", possibly cutting the price tag for a future program that already threatens to balloon to extreme costs. This will only occur, of course, if various technological problems with the MSLs are ironed out and the missions are demonstrated as feasible during the 2009 missions. Not only will this take advantage of the lower cost per rover, but also would not require newly designed and specially incorporated rovers for the Mars ascent vehicles.
| Mars Spacecraft Missions | |
|---|---|
| Flybys: Mariner 4 | Mariner 6 | Mariner 7 | Mars 4 | Rosetta | |
| Orbiters: Mariner 9 | Mars 2 | Mars 3 | Mars 5 | Mars 6 | Viking 1 | Viking 2 | Phobos 2 | Mars Global Surveyor | Mars Odyssey | Mars Express Orbiter | Mars Reconnaissance Orbiter | |
| Landers and Rovers: Mars 3 | Viking 1 | Viking 2 | Mars Pathfinder | Spirit rover | Opportunity rover | |
| Future: Dawn (2007) | Phoenix Scout (2007) | Mars Science Laboratory (2009) | Phobos-Grunt (2009) | Mars 2011 | ExoMars (2013) | Astrobiology Field Laboratory (2016?) | |
| See also: Mars | Exploration of Mars | Colonization of Mars | |
- ^ Salle B., Lacour J. L., Mauchien P., Fichet P., Maurice S., Manhes G. (2006). "Comparative study of different methodologies for quantitative rock analysis by Laser-Induced Breakdown Spectroscopy in a simulated Martian atmosphere". Spectrochimica Acta Part B-Atomic Spectroscopy 61 (3): 301-313. DOI:10.1016/j.sab.2006.02.003.
- ^ CESR presentation on the LIBS
- ^ R. Rieder, R. Gellert, J. Brückner, G. Klingelhöfer, G. Dreibus, A. Yen, S. W. Squyres (2003). "The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers". J. Geophysical Research 108: 8066. DOI:10.1029/2003JE002150.
- ^ Sarrazin P., Blake D., Feldman S., Chipera S., Vaniman D., Bish D. (2005). "Field deployment of a portable X-ray diffraction/X-ray flourescence instrument on Mars analog terrain". Powder Diffraction 20 (2): 128-133. DOI:10.1154/1.1913719.
- ^ Cabane M., Coll P., Szopa C., Israel G., Raulin F., Sternberg R., Mahaffy P., Person A., Rodier C., Navarro-Gonzalez R., Niemann H., Harpold D., Brinckerhoff W. (2004). "Did life exist on Mars? Search for organic and inorganic signatures, one of the goals for "SAM" (sample analysis at Mars)". Source: Mercury, Mars and Saturn Advances in Space Research 33 (12): 2240-2245.
M. K. Lockwood (2006). "Introduction: Mars Science Laboratory: The Next Generation of Mars Landers And The Following 13 articles ". Journal of Spacecraft and Rockets 43: 257-257.
- MSL Home Page
- Malin Space Science Systems
- JPL's Mars Technology Program site
- Mars Science Laboratory Acquisition Program
- Short description of EDL system (PDF)
- Next on Mars (Bruce Moomaw, Space Daily, March 9, 2005): An extensive overview of NASA's Mars exploration plans, with many details on the Mars Science Laboratory
- nuclearspace.com overview of MSL
- MSL EDL Video located on YouTube