Support for continuing Co-I Participation in NASA's OSIRIS-REx sample return mission.

Unravelling the composition of the regolith of rocky airless bodies such as the Moon, asteroids and comets provides a window into the formation and evolution of the Solar System. This STFC urgency request is to enable critical support during a key phase of NASA's OSIRIS-REx asteroid sample return mission (PI D. Lauretta, University of Arizona). Laboratory spectral measurements generated by Oxford as part of a wider test of the mission's data reduction and analysis pipelines have identified serious shortcomings in existing data. This proposal is to make vital new measurements and update our thermal transfer models which will be essential for compositional mapping once the spacecraft arrives at asteroid Bennu in summer 2018 and for sample site selection in 2019. This will maximise the scientific success of OSIRIS-REx's encounter with Bennu.
Background: The composition of airless bodies can in principle be determined remotely by measuring their reflection and emission spectra and comparing the data to spectral libraries of analogue materials measured in laboratories here on Earth.
The OSIRIS-REx spacecraft includes a full complement of remote sensing instruments including visible to near-infrared and thermal spectrometers. However, any measured spectra can be strongly affected by local thermal environment. For example, we have demonstrated that the presence of strong near-surface thermal gradients in Apollo, meteorite and analogue samples can cause shifts in the positions and relative intensities of the diagnostic features in their thermal infrared (TIR) spectra. These changes in the TIR spectra make existing spectral libraries unreliable in determining surface compositions of airless bodies. This proposal addresses this issue and applies the results to spatially resolved data from a primitive asteroid for the first time.

Public engagement:

The success of ESA's recent Rosetta mission to comet 67P has shown the huge public interest that can be generated by space science, and we expect OSIRIS-REx to produce similar levels of excitement once the spacecraft arrives at the asteroid in summer 2018. Through our close involvement in the mission we will be able to explain and share our scientific discoveries with the general public and students, and to encourage greater participation, enthusiasm and interest in science and technology.

Novel Spacecraft Instrumentation:

Our space instrument development activity involves collaboration with several UK industrial partners, where we are combining technology we have developed for planetary science instrumentation with subsystems from our partners to enable a new class of radiometers for small Earth observation spacecraft. For example, in July 2014 we celebrated the launch and successful commissioning of the first of these, the Compact Modular Sounder instrument, on the UK TechDemoSat-1 mission in collaboration with RAL Space. The work described in this proposal includes the measurement and application of new spectroscopic data for remote sensing of airless bodies (specifically near-Earth asteroid Bennu) and will feed directly into new instrument designs as part of proposals to e.g. ESA's recent M5 mission call.

Laboratory materials characterisation:

The laboratory capabilities that are exemplified by this proposal will allow a much wider user group to gain commercial benefit from using our facility. This includes, for example, carrying out specialist spectroscopic investigations of terrestrial materials under appropriate environmental conditions for use in analysing remote sensing observations of the Earth.

Building Connections:

The experience gained from this project will assist with preparation for future missions (especially in ESA's Cosmic Vision programme) and this will inform and enable involvement by UK companies. Current examples include discussions with UK companies to provide detectors and optics for e.g. a multiple asteroid flyby mission.