Influence of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) on the local atmospheric environment

Ralph D Lorenz; Eric S Clarke

doi:10.1016/j.pss.2020.105075

Influence of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) on the local atmospheric environment

Planet Space Sci. 2020 Nov 15:193:105075. doi: 10.1016/j.pss.2020.105075. Epub 2020 Aug 31.

Authors

Ralph D Lorenz¹, Eric S Clarke²

Affiliations

¹ Johns Hopkins Applied Physics Laboratory, Laurel, MD, 20723, USA.
² Idaho National Laboratory, Idaho Falls, ID, USA.

Abstract

A survey around a recently-fueled MMRTG in the terrestrial atmosphere finds a warm air plume with a characteristic updraft velocity of ~1 m/s and a temperature rise of ~4 K. Additionally, a roughly hundredfold enhancement in ion density to ~70,000/cm³ in the vicinity (<~1 m) of the generator was observed: air electrical conductivity was measured to be ~10^-13 S/m. No evidence of ozone production was detected. These observations inform the electrical charging environment and possible local perturbation to meteorological measurements on Mars or Titan on MMRTG-powered landers or rovers. On Mars, the effects of any electrical conductivity enhancement are likely small, but on Titan they may be significant.

Keywords: Atmospheric electricity; Meteorology; Planetary landers; Thermal plume.