ARCHITECTURE OF SPACE PROBES

·         The Rover’s "body": The rover body is called the warm electronics box, or "WEB" for short. Like a car body, the rover body is a strong, outer layer that protects the rover´s computer, electronics, and batteries (which are basically the equivalent of the rover´s brains and heart). The rover body thus keeps the rover´s vital organs protected and temperature-controlled.

·    The Rover’s "brains": The rover computer (its "brains") is inside a module called "The Rover Electronics Module" (REM) inside the rover body. The communication interface that enables the main computer to exchange data with the rover´s instruments and sensors is called a "bus" (a VME or Versa Module Europa bus to be exact). This VME bus is an industry standard interface bus to communicate with and control all of the rover motors, science instruments, and communication functions. It contains special memory to tolerate the extreme radiation environment from space and to safeguard against power-off cycles so the programs and data will remain and will not accidentally erase when the rover shuts down at night. On-board memory includes 128 MB of DRAM with error detection and correction and 3 MB of EEPROM. That´s roughly the equivalent memory of a standard home computer. Activities such as taking pictures, driving, and operating the instruments are performed under commands transmitted in a command sequence to the rover from the flight team. The rover generates constant engineering, housekeeping and analysis telemetry and periodic event reports that are stored for eventual transmission once the flight team requests the information from the rover.

·   The Rover’s temperature controls: Rover cannot function well under excessively hot or cold temperatures. In order to survive during all of the various mission phases, the rover´s "vital organs" must not exceed extreme temperatures of -40º Celsius to +40º Celsius. There are several methods engineers used to keep the rover at the right temperature:

ü  Preventing heat escape through gold paint

ü  Preventing heat escape through insulation called "aerogel"

ü  Keeping the rover warm through heaters

ü  Making sure the rover is not too hot or cold through thermostats and heat switches

ü  Making sure the rover doesn't get too hot through the heat rejection system

·      The Rover’s "neck and head": What looks like the rover "neck and head" is called the Pancam Mast Assembly. It stands from the base of the rover wheel 1.4 meters tall (about 5 feet). This height gives the cameras a special "human geologist´s" perspective and wide field of view.

The pancam mast assembly serves two purposes:

ü  to act as a periscope for the Mini-TES science instrument that is housed inside the rover body for thermal reasons

ü  to provide height and a better point of view for the Pancams and the Navcams . Essentially, the pancam mast assembly enables the rover to see in the distance. The higher one stands, the more one can see.

·         The Rover's "eyes" and other "senses": Each rover has nine "eyes."

Six engineering cameras aid in rover navigation and three cameras perform science investigations.

Four Engineering Hazcams (Hazard Avoidance Cameras):

Mounted on the lower portion of the front and rear of the rover, these black-and-white cameras use visible light to capture three-dimensional (3-D) imagery. This imagery safeguards against the rover getting lost or inadvertently crashing into unexpected obstacles, and works in tandem with software that allows the rover make its own safety choices and to "think on its own."

Two Engineering Navcams (Navigation Cameras):

Mounted on the mast (the rover "neck and head), these black-and-white cameras use visible light to gather panoramic, three-dimensional (3D) imagery. The Navcam is a stereo pair of cameras, each with a 45-degree field of view to support ground navigation planning by scientists and engineers. They work in cooperation with the Hazcams by providing a complementary view of the terrain.

Two Science Pancams (Panoramic Cameras):

The Pancam is also part of the rover's navigation system. With the solar filter in place, the Pancam can be pointed at the Sun and used as an absolute heading sensor. Like a sophisticated compass, the direction of the Sun combined with the time of day tells the flight team exactly which way the rover is facing.

One Science Microscopic Imager:

This monochromatic science camera is mounted on the robotic arm to take extreme close-up pictures of rocks and soil. Some of its studies of the rocks and soil help engineers understand the properties of the smaller rocks soil that can impact rover mobility.

·       The Rover’s "arm": The rover arm (also called the instrument deployment device or IDD) holds and maneuvers the instruments that help scientists get up-close and personal with planets rocks and soil.

Much like a human arm, the robotic arm has flexibility through three joints: the rover's shoulder, elbow, and wrist. The arm enables a tool belt of scientists´ instruments to extend, bend, and angle precisely against a rock to work as a human geologist would: grinding away layers, taking microscopic images, and analyzing the elemental composition of the rocks and soil.

·        The Rover’s wheels "legs": Rover has six wheels, each with its own individual motor. The two front and two rear wheels also have individual steering motors (1 each). This steering capability allows the vehicle to turn in place, a full 360 degrees. The 4-wheel steering also allows the rover to swerve and curve, making arching turns. The rover has a top speed on flat hard ground of 5 centimeters (2 inches) per second. However, in order to ensure a safe drive, the rover is equipped with hazard avoidance software that causes the rover to stop and reassess its location every few seconds. So, over time, the vehicle achieves an average speed of 1 centimeter per second. The rover is programmed to drive for roughly 10 seconds, then stop to observe and understand the terrain it has driven into for 20 seconds, before moving safely onward for another 10 seconds.

·         The Rover’s energy: The main source of power for each rover comes from a multi-panel solar array. When fully illuminated, the rover solar arrays generate about 140 watts of power for up to four hours per sol. The rover needs about 100 watts (equivalent to a standard light bulb in a home) to drive.

·       The Rover’s antennas: The rover has both a low-gain and high-gain antenna that serves as both its "voice" and its "ears". They are located on the rover equipment deck (its "back").

The low-gain antenna sends and receives information in every direction; that is, it is "Omni-directional." The antenna transmits radio waves at a low rate to the Deep Space Network (DSN) antennas on Earth. The high-gain antenna can send a "beam" of information in a specific direction and it is steerable, so the antenna can move to point itself directly to any antenna on Earth.

The radio waves to and from the rover are sent through the orbiters using UHF antennas, which are close-range antennas which are like walky-talkies compared to the long range of the low-gain and high-gain antennas.