Overview:

Crew 50 at the Mars Desert Research Station (MDRS) closed off the facility's fifth field season of operation with a busy, yet successful, week. Of its eight members, five are undergraduate students at Penn State University, and two are undergraduate students at Embry-Riddle Aeronautical University. The crew's rotation focused on three areas: testing the Penn State rover, further developing the rules and guidelines for the upcoming University Robotics Competition and studying the interaction between an astronaut and a rover assistant.

PSUMS Rover Performance:

Over the past week, the Penn State University Mars Society (PSUMS) team tested their rover project for the first time on "Martian" soil. The initial testing led to some modifications of the electrical system, including the addition of fuses and fans, to help the rover handle the required load. The current rover included a locomotion system and a gripper with two degrees of freedom for placement and retrieval of objects. Further testing showed that the rover's maximum speed was about 1.0 mph forward and 1.2 mph backward. The maximum slope the rover could climb on typical soil in the area was about 10 degrees forward and 12 degrees backward. This measure would probably change in different types of soil. The soil at the testing site was loose on the top, but in harder-packed soil the wheels might be less likely to slip. The last portion of the testing showed that the rover's gripper system is functional, though it is not able to pick up very small objects.

The rover testing suggested several possible improvements for the rover. One such improvement is a change in the drive system from the current pulley system to a gear system, since in many situations the belts would slip on the pulleys before the wheels would slip on the ground. This change might allow the rover to climb steeper hills. Another change to improve traction would be to change the wheels from a toroidal shape to a cylindrical shape for more contact with the ground. For easier transportation, the frame could also be lightened from the current steel and aluminum frame to an entirely aluminum frame. Likewise, a lighter set of wheels than the current wheelbarrow wheels can be used. To improve the gripper, limit switches can be implemented to add a degree of intelligence to its motion, and motor placement can be changed to allow a wider range of motion. These and other changes will be implemented in the coming year.

University Robotics Competition:

Another goal of this crew rotation was to further develop rules for an upcoming University Robotics Competition (URC). The PSUMS rover was used as an example of what a typical university team might be expected to create for the competition. With the abilities of the PSUMS rover in mind, a potential site for one of the competition tasks was chosen. The site is less than half a mile from the Hab, making the Hab an ideal base of operations. Further refinements to the competition rules will be made in the coming weeks.

Astronaut-Rover Interaction Study:

In the study of the astronaut-rover relationship, the most important thing to remember is that a rover is to be only used as a tool to assist an astronaut. The design should be kept simple as to not hinder the astronauts duties. As the rover design becomes more complex, the possibility of failure increases. An astronaut should not spend valuable time maintaining a rover.

Three configurations were studied as follows: rover as a surveillance instrument, as a recon scout, and as a scientific assistant. It was concluded that a certain level of autonomous capability was needed in order to be effective for an astronaut. The rover should not be intended to replace a crewmember, only augment an astronaut in his/her duties. It is believed that a human is the most capable and valuable scientific instrument, and a rover is not a sufficient substitute.