 |
| Image for representative purpose only. |
Find Out in Details About the Advance Devices and Technologies Used in the Mars Reconnaissance Orbiter (MRO)
Here we continue with the third part of our blog on space science and technology. Those who have missed our second blog can read it from Here. It will help to connect with this third part of the blog discussing in details about the different advance devices and technologies used in the Mars Reconnaissance Orbiter (MRO). In our previous blog we presented a brief introduction about MRO, its objectives and about the launch of the spacecraft and now we dive into the advance devices and high-class technologies that were used in MRO. Let us explore the blog to find about those in more details.
Three cameras, two spectrometers and a radar are included on the orbiter along with two "science-facility instruments", which use data from engineering subsystems to collect science data. Three technology experiments will test and demonstrate new equipment for future missions. It is expected MRO will obtain about 5,000 images per year.
HiRISE (Camera)
The High Resolution Imaging Science Experiment camera is a 0.5 m (1 feet 8 inches) reflecting telescope, the largest ever carried on a deep space mission, and has a resolution of 1 micro-radian (μrad), or 0.3 m (1 ft. 0 in.) from an altitude of 300 km (190 mi). In comparison, satellite images of Earth are generally available with a resolution of 0.5 m (1 ft. 8 in.), and satellite images on Google Maps are available to 1 m (3 ft. 3 in). HiRISE collects images in three colour bands, 400 to 600 nm (blue-green or B-G), 550 to 850 nm (red) and 800 to 1,000 nm (near infrared or NIR). Red colour images are 20,264 pixels across (6 km (3.7 mi) wide), and B-G and NIR are 4,048 pixels across (1.2 km (0.75 mi) wide). HiRISE's on-board computer reads these lines in time with the orbiter's ground speed, and images are potentially unlimited in length. Practically however, their length is limited by the computer's 28 Gigabit (Gb) memory capacity, and the nominal maximum size is 20,000 × 40,000 pixels (800 megapixels) and 4,000 × 40,000 pixels (160 megapixels) for B-G and NIR images. Each 16.4 Gb image is compressed to 5 Gb before transmission and release to the general public on the HiRISE website in JPEG 2000 format. To facilitate the mapping of potential landing sites, HiRISE can produce stereo pairs of images from which topography can be calculated to an accuracy of 0.25 m (9.8 in). HiRISE was built by Ball Aerospace & Technologies Corp.
CTX (Camera)
The Context Camera (CTX) provides grayscale images (500 to 800 nm) with a pixel resolution up to about 6 m (20 feet). CTX is designed to provide context maps for the targeted observations of HiRISE and CRISM, and is also used to mosaic large areas of Mars, monitor a number of locations for changes over time, and to acquire stereo (3D) coverage of key regions and potential future landing sites. The optics of CTX consist of a 350 mm (14 in) focal length Maksutov Cassegrain telescope with a 5,064 pixel wide line array CCD. The instrument takes pictures 30 km (19 mi) wide and has enough internal memory to store an image 160 km (99 mi) long before loading it into the main computer. The camera was built, and is operated by Malin Space Science Systems. CTX mapped 50% of Mars by February 2010.
MARCI (Camera)
The Mars Colour Imager (MARCI) is a wide-angle, relatively low-resolution camera that views the surface of Mars in five visible and two ultraviolet bands. Each day, MARCI collects about 84 images and produces a global map with pixel resolutions of 1 to 10 km (0.62 to 6.21 mi). This map provides a daily weather report for Mars, helps to characterize its seasonal and annual variations, and maps the presence of water vapour and ozone in its atmosphere. The camera was built and is operated by Malin Space Science Systems. It has a 180-degree fisheye lens with the seven colour filters bonded directly on a single CCD sensor.
CRISM (Spectrometer)
The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument is a visible and near infrared (VNIR) spectrometer that is used to produce detailed maps of the surface mineralogy of Mars. It operates from 370 to 3920 nm, measures the spectrum in 544 channels (each 6.55 nm wide), and has a resolution of 18 m (59 feet) at an altitude of 300 km (190 mi). CRISM is being used to identify minerals and chemicals indicative of the past or present existence of water on the surface of Mars.
Mars Climate Sounder
The Mars Climate Sounder (MCS) looks both down and horizontally through the atmosphere in order to quantify the global atmosphere's vertical variations. It is a spectrometer with one visible/near infrared channel (0.3 to 3.0 μm) and eight far infrared (12 to 50 μm) channels selected for the purpose. MCS observes the atmosphere on the horizon of Mars (as viewed from MRO) by breaking it up into vertical slices and taking measurements within each slice in 5 km (3.1 mi) increments. These measurements are assembled into daily global weather maps to show the basic variables of Martian weather: temperature, pressure, humidity, and dust density.
SHARAD (Radar)
SHARAD is designed to operate in conjunction with the Mars Express MARSIS, which has lower resolution but penetrates to a much greater depth. Both SHARAD and MARSIS were made by the Italian Space Agency.
Engineering Instruments
In addition to its imaging equipment, MRO carries a variety of engineering instruments. The Gravity Field Investigation Package measures variations in the Martian gravitational field through variations in the spacecraft's velocity. Velocity changes are detected by measuring doppler shifts in MRO's radio signals received on Earth. The package also includes sensitive onboard accelerometers used to deduce the in situatmospheric density of Mars during aero braking. The Optical Navigation Camera images the Martian moons, Phobos and Deimos, against background stars to precisely determine MRO's orbit. Although moon imaging is not mission critical, it was included as a technology test for future orbiting and landing of spacecraft. The Optical Navigation Camera was tested successfully in February and March 2006. There is a proposal to search for small moons, dust rings, and old orbiters with it.
No comments:
Post a Comment