Science Seminars

1/7/2016 – Jan-Erik Wahlund; Heavy Metal – An ESA M5 mission to a metallic asteroid

Speaker: Jan-Erik Wahlund (Swedish Institute of Space Physics)
Date: Thursday, Jan 07, 2016
Time: 4:00 PM
Location: SPSC N100

Seminar Abstract:

(16) Psyche is the largest known M-class asteroid (240 x 185 x 145 km), and a density of 5 – 8 g/cm(3) is inferred from orbit perturbations of nearby asteroids. Other ground observations suggest that the surface and dust around this object is iron-nickel rich with very little water. These observations are important considering the difficulty in classifying M-class asteroids correctly. So far, no spacecraft mission has visited a pure metallic asteroid, which are thought to be the exposed metallic core of a larger differentiated parent planetasimal, i.e., a remnant of a molten magnetized core of a planetary like body. The M-class asteroids are also believed to be magnetized to a few micro-Tesla, since the presumed parrent iron-nickel-cobolt rich meteorites falling onto our surface are magnetized to these levels. A metallic asteroid should not only be magnetized, but its presumed large conductivity would be an excellent medium for induced currents by a time variable solar wind interacting with this asteroid type. Mini-magnetospheres should develop, and the M-class asteroids may therefore constitute a new type of space physics objects.The spacecraft mission to the M-class asteroid (16) Psyche was first proposed as a pure Swedish flyby mission (<40 M€) in 2011, but also as a small class (S-class, <50 M€) ESA mission in 2012. It was then called METAL, and both temporarily failed. Now, a larger European team is proposing Heavy Metal, which is an ESA M-class (<550 M€) mission to orbit (16) Psyche (or (216) Kleopatra), use electric propulsion to get there, and deploy two small CubeSat:s to do a close encounter with this exotic asteroid. A new smaller Swedish mission proposal is also being considered. One complication/opportunity/advantage is that a similar Discovery mission has been selected for further studies in the USA.
I will present the science case for (16) Psyche, and what different mission plans there exist to pursue this science.