Present-day thermal and water activity environment of the Mars Sample Return collection.

The Mars Sample Return mission intends to retrieve a sealed collection of rocks, regolith, and atmosphere sampled from Jezero Crater, Mars, by the NASA Perseverance rover mission. For all life-related research, it is necessary to evaluate water availability in the samples and on Mars. Within the first Martian year, Perseverance has acquired an estimated total mass of 355 g of rocks and regolith, and 38 μmoles of Martian atmospheric gas.

Enzymatically catalyzed CO -H O equilibration for oxygen isotope analyses of aqueous samples.

Rationale: The classic CO -H O equilibration method is a very popular technique for the measurement of the oxygen isotope composition of aqueous samples in stable isotope geochemistry. This study examined whether enzymatically controlled CO -H O equilibration by carbonic anhydrase (CA) could reduce the time for oxygen isotope equilibrium between CO and H O at 25°C.

Methods: Four types of aqueous samples containing CA were equilibrated with CO gases using a continuous flow isotope ratio mass spectrometer equipped with an automated gas sample collection device.