LUNAR ROVER

OVERVIEW

Once the landing craft has successfully soft-landed on the lunar surface, the success or failure of the mission will be determined by intelligent, diligent design of the rover vehicle. The rover must be capable of traversing a minimum distance of 500 m, with additional prize money for traveling 5 km from the landing site. During the journey, the rover must contend with a challenging environment consisting of thick and dusty soil, craters, boulders, and rock formations. The rover must also be able to plot a course that will pass by remnants of previous Apollo landings in order to achieve bonus incentives, which limits its ability to choose the easiest route. In addition to successfully navigating on the lunar surface, the rover must be equipped to document its journey by sending “Mooncasts” back to the Earth. High definition sensors will need to capture still images and video, and the rover must possess sufficient processing power to encode and relay the transmissions, all while maintaining steady progress along its course. Finally, the rover must be capable of performing these tasks under extreme temperatures, ranging from below -200ºC to above 100ºC.

The rover will consist of a suspension and chassis made of 6061 aluminum, a lightweight and strong metal commonly used in the aerospace industry. The suspension itself will follow the Rocker-Bogie design developed by NASA’s Jet Propulsion Lab in the late 1980s. Able to withstand tilts of 45º in any direction with only passive parts, the Rocker-Bogie suspension was utilized on both the Mars Sojourner rover and the Mars Exploration Rovers, Spirit and Opportunity. In our design, the Rocker-Bogie suspension will allow the rover to drive over obstacles up to 9 cm high, an impressive 50% taller than the wheel itself. A solar panel will be placed on top of the suspension system, and the warm electronics box will be located in the central cavity. The last major component is the periscope, upon which the high definition cameras will be mounted to provide 360º panoramic views.

Figure 1. 3D CAD Preliminary Rover Design

Because size and mass are the determining factors in launch costs, the rover design must be small and lightweight. The final rover design is 60 cm long, 35 cm wide, and 40 cm tall, which is primarily dictated by the solar panel and whip antenna. Mass was a prime consideration during the design, and this diligence paid off with a total mass of approximately 12 kg. With these specifications, the rover, similar in size to the Mars Sojourner, should minimize launch costs. Preliminary 3D CAD drawings of the rover can be download HERE.

Component

Mass [kg]

Suspension/Panel/WEB/Periscope/Wheels

7.45

Motors

0.156

Harmonic Drives

1.98

Li Batteries

0.555

Radioisotope Heater Units

0.32

CPU/Board

0.549

Cameras/Sensors

0.1

Turret Stepper Motor

0.025

Amps/Mixers/Filters/Antennas

0.865

Total

12

Table 1. Rover Mass Distribution

Although the cost of the launch is the primary expense associated with this challenge, the cost of the rover must also be kept to a minimum. The final cost of the unassembled rover is projected to be $215,000. Analyzing the cost breakdown, the driving factor behind the rover cost is the radiation-hardened CPU and board. Given our anticipated launch costs in the $7 to $8 million range and the critical role serviced by this component, the design team elected to make this purchase. If the radiation-hardened CPU was foregone in favor of traditional, commercial silicon electronics, the anticipated rover costs would drop to below $20,000.

Item

Cost

Motors

$360.00

Harmonic Drives

$1,200.00 (est)

Solar Panel

$1,000.00 (est)

HD CMOS Image Sensors

$90.00

VGA CMOS Image Sensors

$160.00

Infrared Proximity Sensors

$65.00

CPU/Board

$200,000.00

MPEG-4 Encoder

$10.00

Li Batteries

$100.00

Chassis/Suspension/Wheels

$5,000.00 (est)

Miscellaneous/Other

$7,000.00 (est)

Total

$215,000.00