Beagle 2 Microscope

Introduction

The Beagle 2 Microscope was a compact and light - yet very powerful - optical microscope onboard the lander Beagle 2 which was carried on ESA's MarsExpress mission. On the Martian surface the instrument acquires images of rocks, soil and dust with a resolution of 6 microns, which is 25x more accurate than the human eye. Using a novel illumination system it can generate full colour images and detect fluorescence to look for indications of life. The target is brought into focus using a translation stage. With this position information a digital elevation model (DEM) of the target surface is acquired at the same time. 
 

The PIGs were involved in the development and testing of the microscope system for Beagle 2. We describe here in brief the aims and performance of the microscope.

Scientific Objectives

A microscope has four distinctly different tasks in a lander package.

- Firstly, the instrument can be used to study the physical and structural properties of a surface and hence make a good geophysical analysis and contribute to the overall geological and mineralogical interpretation of the landing site.

- Secondly, a microscope can contribute to studies of the atmosphere of Mars. Specifically, dust particles are continuously precipitating out of the dusty atmosphere and hence a microscope can be used to constrain the sizes and shapes of particles for input into atmospheric scattering and radiative transfer models of Martian atmosphere.

- Thirdly, the instrument can be used to study the morphology of a potentially biological sample and hence identify structures which may be characteristic of past or present biological activity.

Finally, the instrument can be used to characterize and/ or select a sample before it is passed to another analytical instrument. It is used therefore to assist the chemical analysis.

Instrument Design

The Beagle 2 microscope consists of several natural elements.

- The illumination system and the optics are so compact that they naturally form one work package.

- The detector element with read-out electronics forms a second work package.

- These two elements are joined by a tube which provides a mechanical interface and a light-tight structure of significant strength.

- The translation stage forms a fourth work package.

And for the future?

A modified version of the Beagle 2 microscope was proposed for the MicrOMEGA instrument onboard ExoMars (PI: J.-P. Bibring). Following the payload descoping, the optical element of MicrOMEGA was cut after successful PDR. However, we have resurrected the concept and integrated it with a laser ablation mass spectrometer to produce an ultra-low mass instrument for planetary surface investigations. It is called CAMEM. 

Relevant Publications

Lüthi, B.S., Thomas, N., Hviid, S.F., Rueffer, P. (2010) An efficient autofocus algorithm for a visible microscope on a Mars lander. Planetary and Space Science 58, 1258-1264 doi:10.1016/j.pss.2010.05.002.

Thomas, N., Hviid, S.F., Keller, H.U., Markiewicz, W.J., Blümchen, T., Basilevsky, A.T., Smith, P.H., Tanner, R., Oquest, C., Reynolds, R., Josset, J.-L., Beauvivre, S., Hofmann, B., Rüffer, P., Pillinger, C.T., Sims, M.R., Pullan, D., and Whitehead, S. (2004) The microscope for Beagle 2. Planet Space Sci., 52, 853-866.

Tulej, M., A. Riedo, M.B. Neuland, S. Meyer, P. Wurz, N. Thomas, V. Grimaudo, P. Moreno-García, P. Broekmann, A. Neubeck, and M. Ivarsson, (2014), CAMAM: A miniature laser ablation ionisation mass spectrometer and camera-microscope system for in situ investigation of the composition and morphology of extraterrestrial materials, Geostandards and Geoanalytical Research, submitted, June 2014.