Chemistry of Outer Solar System Materials
EMSL Project ID
19806
Abstract
We propose to continue our study of the chemistry and optical properties of materials thought to exist on the surfaces of outer Solar System objects. We have studied at EMSL a variety of hydrated salt minerals, demonstrated their likely presence and explored their chemistry on the Europa surface (satellite of Jupiter) (four publications, one Ph.D. dissertation and 3-4 presentations/yr at professional meetings resulted). We showed that these salts likely originated from a subsurface ocean, where life could have developed, and constrained the ocean composition. We recently extended to organic compounds called tholins that are thought to result from energy dissipation in mixtures of simple H, C and N molecules, such as methane and ammonia, and apparently exist in the outer Solar System. The environment of interest is the Titan surface (satellite of Saturn), where tholin is thought to fall as rain from the thick atmosphere.We are members of a team studying tholins that includes Drs. Mark Smith and Jonathan Lunine of the U. of Arizona, Patricia Beauchamp of the Jet Prop. Lab. and Jesse Beauchamp of Caltech. Smith produces the sample material, the Beauchamps study the compositions and chemistry, and we study the material behavior under simulated outer solar system conditions. We bring unoxidized samples of the tholins to EMSL in sealed containers, insert them in the vacuum chamber using a small sample holder we developed, and observe the optical properties using IR spectroscopy with temperature, pressure, under irradiation and in contact with H2O.
These studies are in direct support of several NASA flagship deep space missions: Galileo and Cassini. We recently received a 3-year renewal of a NASA Basic Research (Cosmochemistry) Program grant that supported our earlier work. We also received a new 3-yr NASA grant to re-analyze the Galileo mission spectroscopic data, using better calibrations and to continue our salts studies. Thus, we have stable funding in peer-reviewed national research programs. The basic research questions are fundamental, namely, do environments exist (Europa’s ocean; Titan’s surface) where life can exist and can life develop independent of the Earth. In general, we are trying to understand the chemistry of the basic minerals and molecules present under the environmental conditions of outer Solar System object surfaces, which is what is observable from space.
Very low temperatures, high vacuum and a variety of radiation sources (electrons, ions, UV) are needed to simulate the environments. Equipment to create these environments is highly specialize and beyond the resources of most researchers. The EMSL facilities have proven effective for our research. A special need not satisfied by EMSL has been a near infrared reflectance spectrometer to observe samples in the vacuum chamber but we have managed to provided our own spectrometer and control/data electronics and devised an interface with the chamber. We hope to conduct a series of 2-4-day experiments over the next three years using the vacuum chamber and coolers we have been using and our present spectrometer setup. The PI will be assisted by Drs. G. Hansen and R. Hodyss.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-09-01
End Date
2008-10-27
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members