NanoSIMSNanoSIM (left), NMR (right) NMR

MarcoPolo-R will allow us to analyze the sample of a primitive NEA in terrestrial laboratories, thereby obtaining measurements that cannot yet be performed from a robotic spacecraft (e.g. dating the major events in the history of a sample: laboratory techniques can determine the time interval between the end of nucleosynthesis and agglomeration, the duration of agglomeration, time of accumulation, crystallization age, the age of major heating and degassing events, the time of metamorphism, the time of aqueous alteration, and the duration of exposure to cosmic radiation). One of the main objectives of these analysis is the identification and characterization of organic materials, which may have contributed to the origin of Life on Earth.

In almost all cases no single measurement, or type of measurement, will provide the complete answer to any of the questions. Instead, our understanding will be derived from the results of many analyses of different components of the returned sample, and by a plethora of techniques. The Figure below shows the example of an instrument and related measurements that can be done to infer absolute ages.

TIMSslice

PBratio

Absolute ages for the formation of solar nebula components, i.e. CAIs and chondrules (above right), can be determined by radiometric dating techniques. This requires very specialised mass spectrometer systems such as TIMS (above left) or ICPMS to provide the high precision, sensitivity and mass resolution for the accurate isotope ratio measurements of trace elements such as Pb (left). Analyses of sub-samples permit ages of more than 4.5x109 years with uncertainties of less than 106 years to be acquired. Images courtesy Univ. Hawaii and Norton and Toffoli. Data from Amelin et al. 2002.