LUNAR ROVER

CAMERAS AND SENSORS

Once deployed on the lunar surface, the rover will rely upon cameras and sensors for both navigation and documentation. These electronics will be fully exposed to the extreme lunar environment; therefore, careful consideration is necessary when selecting the components. The modern digital documentation stipulations place further restrictions upon the available camera choices. The X-Prize requires the transmission of a “Mooncast”, which includes high resolution 360º photographs and streaming high definition (HD) video. The Micron MT9P401 CMOS image sensor was chosen to fulfill the documentation needs of the rover. This 5-Megapixel sensor is capable of streaming 720p HD video, while operating over a wide temperature range and with minimal power consumption. In addition, the MT9P401 is a complete system-on-chip design (SOC), meaning it only requires a lens, power supply, and clock to operate. Two of these sensors will be located on the periscope to enable 360º shots and provide redundancy. One point of note is that the MT9P401 is only qualified up to 70ºC. In order to obtain top-tier sensors that will operate on the lunar surface, the prior employment connections of team member(s) will leveraged.

Micron MT9P401 CMOS Image Sensor

Resolution

720p at 60 fps

Power Consumption

381 mW

Temperature Range

-30ºC to 70ºC

Cost

$43.42

Number Required

2

Table 1. High Definition Image Sensor Properties

Successful navigation and collision avoidance on the lunar surface will utilize a two-pronged approach. The primary navigation system will employ a network of image sensors placed around the rover, which will then feed the information to image processing software on the central processing unit (CPU) for obstacle recognition. Another CMOS image sensor, the Micron MT9V125 was selected for the navigation system. Employing many of the same features as the HD sensors, the MT9V125 produces VGA quality video (sufficient for path mapping) up to 105ºC and with even less power consumption. Four of these image sensors will be mounted on the rover, one at each corner, along with a fifth on the periscope. In case of image sensor failure or the inability of the software to recognize an obstacle, the rover will also be equipped with a number of infrared proximity sensors to prevent a collision. The Sharp GP2D15 can detect objects from 10 to 80 cm away, which provides sufficient stopping distance. Although only qualified by the manufacturer up to 60º, the temperature dependence data listed in the specification sheet indicates acceptable performance at lunar temperatures. Three of these infrared sensors will be placed on the front of the rover, and two will be placed on the back. Because the rover will be powered down during the lunar night, none of these components will need to function below their lower operating limits.

Micron MT9V125 CMOS Image Sensor

Resolution

480i at 30 fps

Power Consumption

< 300 mW

Temperature Range

-40ºC to 105ºC

Cost

$31.99

Number Required

5

Table 2. Navigation Image Sensor Properties

Sharp GP2D15 Infrared Proximity Sensor

Distance Range

10 to 80 cm

Power Consumption

165 mW

Temperature Range

-10 ºC to 60ºC

Cost

$12.18

Number Required

5