We report the first in situ observation of hollow organic globules in any extraterrestrial material using the Tagish Lake carbonaceous chondrite. Data from analytical transmission electron microscopy, Raman and micro-Fourier-transform infrared (FTIR) spectroscopy indicate that the globules consist of aliphatic and oxygenated functions. The hollow spherical morphologies are strikingly similar to the material produced by the laboratory simulation of ultraviolet photolysis of interstellar ice analogues and subsequent aqueous processing, suggesting that the organic globules in the Tagish Lake meteorite may be extremely primitive organic material that formed before or during the formation of the solar system. The FTIR organic signatures also show strong similarities to the membrane-like products formed from hydrothermal reaction of an OH-bearing amino acid in the presence of hydrous minerals. The survival of the structures in the Tagish Lake sample indicates that primitive meteorites must have delivered these structures to the early Earth as a possible precursor to life.

We propose a new type of robotic mission for the exploration of Mars. This mission is called Vanguard and represents the fruits of a collaboration that is both international and multi-disciplinary. Vanguard is designed for sub-surface penetration and investigation using remote instruments and unlike previous robotic architectures it offers the opportunity for multiple subsurface site analysis using three moles. The moles increase the probability that a subsurface signature of life can be found and by accomplishing subsurface analysis across a transect, the statistical rigour of Martian scientific exploration would be improved. There is no provision for returning samples to the surface for analysis by a gas-chromatograph/mass-spectrometer (GCMS) – this minimizes the complexity invoked by sophisticated robotic overheads. The primary scientific instruments to be deployed are the Raman spectrometer, infrared spectrometer and laser-induced breakdown spectroscope – the Raman spectrometer in particular is discussed. We concentrate primarily on the scientific rationale for the Vanguard mission proposal. The Vanguard mission proposal represents a logical opportunity for extending European robotic missions to Mars.

16–19 September 2002 Graz, Austria