Tumbleweed rovers, now undergoing development, are lightweight, inflatable, approximately spherical exploratory robotic vehicles designed to roll across terrain, using only wind for propulsion. Tumbleweed rovers share many features with "beach-ball" rovers, which were discussed in several prior NASA Tech Briefs articles. Conceived for use in exploring remote planets, tumbleweed rovers could also be used for exploring relatively inaccessible terrain on Earth.
A fully developed tumbleweed rover would consist of an instrumentation package suspended in an inflated two-layer (nylon/polypropylene) ball. The total mass of the rover would be of the order of 10 kg, the diameter of the ball when inflated would be 2 meters, and the minimum wind speed needed for propulsion would be about 5 m/s. The instrumentation package would contain a battery power supply, sensors, a Global Positioning System (GPS) receiver, and a radio transmitter that would send the sensor readings and the GPS position and time readings to a monitoring station via a satellite communication system. Depending on the specific exploratory mission, the sensors could include a thermometer, a barometer, a magnetometer (for studying the terrestrial magnetic field and/or detecting buried meteorites), a subsurface radar system (for measuring ice thickness and/or detecting buried meteorites), and/or one or two diametrally opposed cameras that would take the part of sending two side-looking images out.
In the planned Antarctic field test, a prototype tumbleweed rover was released at a location near the South Pole. Using the global Iridium satellite network to send information about its position, the rover transmitted temperature, pressure, humidity, and light intensity data to NASA's Jet Propulsion Laboratory. The rover reached speeds of 30 km per hour over the Antarctic ice cap, and traveled at an average speed of about 6 km per hour. The test was designed to confirm the rover's long-term durability in an extremely cold environment, with the goal being eventual use of the device to explore the Martian polar caps and other planets in the solar system. On future Antarctic exploratory missions, tumbleweed rovers might be used to acquire sensor data for studies of global warming, ozone depletion, and impacts of meteorites.
This work was done by Alberto Behar, Jack Jones, Frank Carsey, and Jaret Matthews of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free online at www.techbriefs.com/tsp under the Physical Sciences category.
NPO-40499
This Brief includes a Technical Support Package (TSP).
Tumbleweed Rovers
(reference NPO-40499) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package for Tumbleweed Rovers, developed under NASA's Commercial Technology Program. It serves to disseminate the results of aerospace-related developments with broader technological, scientific, or commercial applications. The document is structured into several sections, including acknowledgments, a table of contents, and detailed descriptions of the Tumbleweed systems.
The introduction provides background information and outlines recent developments related to Tumbleweed Rovers. The document then delves into the system architecture and rover system overview, detailing the design and construction of various hardware components, including the central tube, electronics pallet, power system, batteries, and pump system.
A significant portion of the document is dedicated to ground station software development, which includes an overview of LabVIEW, a graphical programming environment used for data acquisition and control. It describes the features of the ground station, such as the "Setup" and "Current Status" fields, and discusses software testing procedures.
The hardware development section outlines the construction of the ground station, while the field test program section summarizes a rigorous testing regimen that Tumbleweed underwent over three months, including deployments in the Mojave Desert. This testing is crucial for assessing the rover's performance in harsh environments.
The document also proposes an endurance field test location on Devon Island, specifically at the Haughton Impact Crater, which is part of the NASA Haughton-Mars Project. This site is considered ideal for testing due to its Mars-like conditions, providing valuable insights for future missions.
In conclusion, the document emphasizes the collaborative efforts of various individuals and organizations, acknowledging their contributions to the Tumbleweed project. It also provides contact information for further inquiries and assistance, highlighting NASA's commitment to sharing knowledge and fostering innovation in aerospace technology.
Overall, the Technical Support Package serves as a comprehensive resource for understanding the Tumbleweed Rovers, their development, and their potential applications in space exploration and beyond.
