Capaciflector | Spectrometer | Conformal Gripper

Wireless Power Transmission


The capaciflector is a sensor invented and patented by John Vranish about fifteen years ago at NASA Goddard Space Flight Center. It is able to sense an object up to 46 cm, which can be applied to collision avoidance, navigation, and mapping an image of the object or terrain. These capaciflectors use electric fields to measure the capacitance between the sensor and the object. Since every material has a unique permittivity, an object can be identified by scanning its permittivity curves vs. frequency information and matching its identity to that stored in a database. This frequency scanning capaciflector provides scientists and engineers with a lightweight and robust device that will have the ability to quickly identify objects and track water/ice boundaries with a rover in cold, dark areas.

Two electrical engineering students from Michigan State University are working with Dr. Charles Campbell, Jr. to take the basic schematics of an old capaciflector and build a new one with scanning capabilities.

For more information on capaciflectors, visit the Capaciflector Technology page.



The ultraviolet spectrometer will be included on the polar bot during its first trip to Antarctica to return important information about the ozone to scientists back at Goddard. During a 24-hr period while the rover is down south, it will be set in a stationary position with a small robotic arm tracking the sun, on which the spectrometer will be attached.


Conformal Gripper

Currently, robotic grippers only hold and carry objects with friction by squeezing objects tight enough so they don't slip out. The problem with this is that different grippers need to be designed for different objects, and fragile objects would get crushed. John Vranish, in Code 544, is working to solve this problem by designing a gripper that will use spring-loaded pins so that it can conform to an object. These pins will then be locked in place by a perpendicular force, provided by gear bearings.

Several interns are working with Vranish to create a model of the gripper using CAD software to test and analyze the forces and tolerances of the design.


Wireless Power Transmission

In order to reach the depths of lunar craters, rovers must have a way to recharge the power that they store. The idea with wireless power is to have one robot at the top of a crater, where it can collect energy from the sun with solar arrays. It will then transmit that power to another robot down inside the crater wirelessly, which will receive and transmit to another robot father down inside until it gets to the mothership robot that has the explorer rovers attached. The bots in the middle are necessary because each needs a direct line of sight for power transmission.

Study for wireless power transmission still needs to take place in the following areas:

- Recommended operating frequency
- Transmitting antenna size and design concept
- Rectenna size and design concept
- Beam redirection, beam-waveguide dimensions and design concept
- Mission profile considerations (range, location and efficiency of power beam)
- Microwave generator considerations
- Radiation hazard protection subsystem
- RFI (interference) study
- Budgetary cost estimates for the system
- Design of proof-of-concept experiment using microwave beam to supply a robotic vehicle (possibly in the high Artic)