NASA’s Mars Rover ‘Curiosity’ to land soon
With inputs from Yash Kodavali
Following two successful expeditions to Mars (Spirit, Opportunity), NASA launched another rover bearing the name Curiosity on November 26, 2011. The widely anticipated touchdown is expected to occur sometime next week. Curiosity symbolizes the next step taken by humans in space exploration – it is by far the biggest vehicle sent into space, about 4 to 5 times heavier than its predecessors at 900 kg and about the size of a Tata NANO, having the biggest ever parachute that is 51 meters in diameter. It is also the most expensive of all the projects undertaken as part of the Mars Planetary Exploration.
Extensive research has gone into mapping a landing site on the Mars. This has been accomplished by analyzing the images provided by the Mars Reconnaissance Orbiter. The chosen site is an ellipse of 7kmX20km on the Gale Crater. The rover has to go through a series of complex S-curve maneuvers to perform a massive scaling of its speed from 22000 km/hr at entry to nearly 1.5 km/hr during landing. The two identical on-board rover computers, called “Rover Compute Element” (RCE), contain radiation hardened memory to tolerate the extreme radiation from space and to safeguard against power-off cycles.
Each computer’s memory includes 256 KB of EEPROM, 256 MB of RAM, 2 GB of Solid State Storage(flash memory). This compares to 3 MB of EEPROM, 128 MB of DRAM, 256 MB of flash memory used in the Mars Exploration Rovers, Spirit and Opportunity.
The RCE computers use the RAD750 CPU, which is a successor to the RAD6000 CPU (both from IBM) used in the Mars Exploration Rovers. The RAD750 CPU is capable of up to 400 MIPS (Million Instructions Per Second), while the RAD6000 CPU is capable of up to 35 MIPS. Of the two on-board computers, one is configured as backup, and will take over in the event of problems with the main computer.
Real Time control is not possible as there is a time lapse of 14 minutes between the Earth and Mars. So the trajectory and telemetry of the rover are currently under the control of an onboard autonomous system while the ground unit keeps tracking it continuously to check if any corrections to its trajectory called TCM are required based on their simulations. Till now 4 Trajectory Correction Manoeuvres have been executed to ensure safe landing of the rover in its designated launching spot inside the ellipse.
The rover is powered by an RTG – Radioisotope Thermoelectric Generator. The RTG is fundamentally a generator that converts heat emanated from radioactive decay of Plutonium-238 into electricity. It was used in the Viking series of landers in 1976. The estimated lifetime of the power source is 14 years. This makes the rover independent of seasons as it is unaffected by sunlight. It can work both in the day and at night.
Curiosity Scientific Payload:
MARDI – Mars Descent Imager: Used to take High definition video of the landing site 2 minutes before landing for (autonomous) determination of safe landing zone.
SAM – SAMPLE ANALYSIS AT MARS
Gas Chromatograph, Mass Spectrometer, Tunable Laser Spectrometer
They work in tandem to identify a wide range of organic (carbon-containing) compounds and determine the ratios of different isotopes of key elements which serve as clues in explaining the atmospheric and hydrological history of Mars.
CheMin - An X-ray Diffraction and Fluorescence Instrument
Designed to identify and quantify the minerals in rocks and soils and to measure their relative composition.
MAHLI- Mars Hand Lens Imager (Mounted on the arm)
Takes extreme close-up pictures of rocks, soil and, if present, ice, revealing details smaller than the width of human hair. It will also be able to focus on hard-to-reach objects that are more than an arm’s length away.
APXS – Alpha Particle X-ray Spectrometer (Mounted on the arm) : Determines the relative abundances of different elements in rocks and soils.
MastCam – The Mast Camera (Mounted at about human-eye height): Captures the rover’s surroundings in high-resolution stereo and color images, with the capability to take and store high-definition video sequences. It will also be used for viewing materials collected or treated by the arm.
ChemCam: An instrument that uses laser pulses to vaporize thin layers of material from Martian rocks or soil targets up to 9 meters (30 feet) away. It will include both a spectrometer to identify the types of atoms excited by the beam, and a telescope to capture detailed images of the area illuminated by the beam. The laser and telescope sit on the rover’s mast and share with the Mast Camera the role of informing researchers’ choices about which objects in the area make the best targets for approaching to examine with other instruments.
RAD- Radiation Assessment Detector: Characterizes the radiation environment at the surface of Mars. This information is necessary for planning human exploration of Mars and is relevant to assessing the planet’s ability to harbor life.
REMS – Rover Environmental Monitoring Station: Provided by Spain’s Ministry of Education and Science, to measure atmospheric pressure, temperature, humidity, winds, plus ultraviolet radiation levels.
DAN – Dynamic Albedo of Neutrons Instrument: Provided by Russia’s Federal Space Agency, to measure subsurface Hydrogen up to one meter (three feet) below the surface. Detection of Hydrogen may indicate the presence of water in the form of ice or bound in minerals.
Sample Acquisition/Sample Preparation and Handling System: Tools to remove dust from rock surfaces, scoop up soil, drill into rocks and collect powdered samples from rocks’ interiors, sort samples by particle size with sieves, and deliver samples to laboratory instruments.
Hazard avoidance cameras (Hazcams)
The rover has two pairs of black and white navigation cameras located on the four corners of the rover. They are used for autonomous hazard avoidance during rover drives and for safe positioning of the robotic arm on rocks and soils. The cameras use visible light to capture stereoscopic three-dimensional (3-D) imagery.
NASA will be providing live streaming of Curiosity’s landing on Mars in a response to heightened ‘curiosity’ from enthusiasts, students and the general public. For a live feed, head to
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Nikhila is a gadget lover and passionate writer. She likes to keep up with social media and Internet culture in particular while staying updated about all latest gizmos. Nikhila is a mechanical engineer-turning-into-technical-writer. Bibliophile, Grammar Nazi, dog lover, foodie, casual artist.
2 August, 2012