IAC-15,A3,2B,4,x29749 QUALIFICATION OF A DUAL ROVER ARCHITECTURE INCLUDING DEPLOY ABLE CAMERAS FOR EXPLORATION OF A SKYLIGHT ON THE LUNAR SURFACE

摘要

In the past several years, based on data from the Japanese Kaguya lunar orbiter and NASA's Lunar Reconnaissance Orbiter, there have been many discoveries of potential lava tube "skylight" entrances on the surface of the moon. The Google Lunar XPRIZE entrant, Hakuto, and the Space Robotics lab of Tohoku University successfully field demonstrated the use of an 8.5 kg parent rover and 2.5 kg tethered child rover to safely explore steep, rocky and vertical terrain like that expected at a skylight. We also qualified these rovers with thermal-vacuum, vibration, radiation and field testing. Based upon successful results, we changed our planned flight model architecture from a heterogeneous system comprising a satellite microcontroller and off-the-shelf, qualified ARM- based controller to a more robust architecture comprising redundant ARM-based controllers and multiple cameras. Using the same components and little development time, we have designed an additional 350 g deployable camera. This is suitable for integration on either of Hakuto's rovers, greatly reducing the total mass required to explore a skylight, and increasing the number of potential missions by making a more flexible overall mass budget. The configuration for the deployable camera consists of a passive, up to 100 m long tether loaded onto a motorized spool and a spring-loaded camera module. The camera module includes a small battery, controller, and a thermal and electrical interface to the rovers. When fully retracted by the motorized spool (located in the rover), a ratchet mechanism locks the module in the loaded position. In this position it can stream images to the rover's main controller via an RS485 or ethernet connection. Upon release of the ratchet mechanism, a one-way clutch allows the module to freely travel as a projectile. Images captured are stored on-board the module until it is once again retracted and they can be transferred to the main controller. By designing the deployable camera module for integration into our two lunar rovers, we have we have upgraded our dual rover architecture to include up to three redundant methods for returning images from a potential lunar cave, even where the entrance would be impossible for a conventional rover to traverse. This allows flexibility in mission architecture to meet the requirements of multiple lunar landing opportunities, multiple landing targets, unfinalized mass budget or a poorly described landing target.