High-Altitude Electromagnetic Sounding of Earth and Planetary Interiors

PI: Robert Grimm, Southwest Research Institute - Boulder, Charles Oden (Co-I), Earth Science Systems

Electromagnetic (EM) sounding uses induction from natural sources to build profiles of electrical conductivity of planetary interiors. The techniques of EM sounding performed from space near the Earth, Moon, and Galilean satellites operate globally at very low frequencies (<<1 Hz) and cannot resolve structures of interest in crusts and upper lithospheres, which are comparatively shallow. Conversely, higher-frequency surveys for shallow structures must be performed at or close to the surface, with associated logistical and mobility challenges.
We have developed a new theory for EM sounding targeting higher frequencies (8Hz to 2kHz) that can resolve this depth interval and applies at any altitude in the waveguide formed between the ground and the ionosphere (Grimm et al., Icarus, 2012). High-altitude aerial platforms can perform measurements over long traverses, and so the approach is applicable to Earth, Venus, Mars, and Titan, which have the necessary waveguide structures and potentially appropriate EM sources. The concept was selected by PICASSO 2015 to develop a prototype high-altitude airborne electromagnetic sounding system for testing on a stratospheric balloon. Although the system incorporates state-of-the-art high-impedance electrometers, it is essentially a knowledge payload to determine if the expected vertical and lateral variations in electric fields can be measured and used to recover the electrical conductivities of the ionosphere and ground.

Background on Schumann Resonance.

Abstract VEXAG2017

Technology Areas (?)
  • TA08 Science Instruments, Observations and Sensor Systems
Problem Statement

If proven successful, this technology will enable global study of the lithospheric structure of Venus and its relation to that planet's unique geodynamic style, groundwater on Mars, and a subsurface ocean on Titan. For Earth, the approach can be used to investigate geological hazards at the regional scale from earthquake fault zones, volcanoes, and landslides, as well as mapping sea-ice thickness and groundwater volumes.

Technology Maturation

TRL of this technology varies between Earth and planetary applications. The stratospheric balloon flights operate in the same environment as would subsequent terrestrial mapping experiments, except the instrumentation would be adapted to different platforms, i.e. entry TRL=4 and exit TRL=7. For planetary science, Earth's stratosphere is not fully relevant to Mars, Venus, or Titan, nor has the instrumentation yet been put on a direct path to space qualification, i.e. entry TRL=2 and exit TRL=4.

Future Customers


Technology Details

  • Selection Date
    NASA Internal (Jul 2016)
  • Program Status
  • Current TRL (?)
    Successful FOP Flights
  • 2 Balloon

Development Team

Web Accessibility and Privacy Notices Curator: Alexander van Dijk Responsible NASA Official: Stephan Ord Last Update: November 16, 2018