Bubble-based Ocean-worlds Organics Sample Trap (BOOST)

Background: Estimated energetic limits for life in Ocean Worlds such as Enceladus and Europa suggest that many current life detection technologies will require pre-concentration of ice or liquid (brine, ocean) samples on the order of 1000X to facilitate detection.

Science Goal: We propose to develop an organic concentrator, BOOST, which could be utilized to process samples from a plume, ice, brine pocket, or liquid, such as from a subsurface ocean.

Objectives: (1) Conduct lab experiments to determine optimal system design. (2) Develop a prototype and evaluate performance on a set of Ocean World analogs. (3) Advance technology readiness level (TRL) from TRL 2 to TRL 4 and characterize steps required to advance BOOST, with further funding, to TRL 6.

Methodology: Our approach is inspired by observations that bubbles can scrub organic material from liquids, that organics concentrate in a sea-surface microlayer, and that bursting bubbles can generate enrichment of organic materials relative to the bulk aqueous phase. Lab experiments will be used to study the impact of device and sample parameters on bubble size, lifetime, number, and other characteristics and related to enrichment of organics across a 10^10 size range, from amino acids to whole cells.

Prior work demonstrates how tuning of parameters affects enrichment, and factors of 10^2 to 10^4 have previously been achieved. Temperature gradients can be used to move bubbles even in the absence of buoyancy (e.g., in weightlessness), and can also be used to promote enrichment through bubble thinning and via convective flow. These lab experiments will be used to optimize the design of BOOST devices, with the boundary conditions represented by a milli-fluidic, single bubble, device up to a one-liter sample capacity device. BOOST would be anti-fouling as it achieves concentration without a physical filter. It is amenable to batch or continuous flow applications.

We will utilize both synthetic analogs, representing Ocean World end-members for Europa and Enceladus, as well as evaluating a range of relevant samples, such as NaCl, MgSO4, and MgCl2 brines from environmental terrestrial analogs being studied under related work by Carr. The ability to concentrate organics (amino acids, protein, nucleic acids, whole cells) will be compared to other methods being utilized to study these samples, and the expected limit of detection (LOD) improvements demonstrated in full-scale life detection tests.

Relevance: Our work is specifically relevant to the solicitation in that it would help provide a critical pathway to enabling life detection for future Ocean Worlds missions (such as at Enceladus, Europa, Titan, or at Mars, a relic Ocean World), as described in the Planetary Science Research Program and the NASA Science Plan. Our work would “substantially improve instrument measurement capabilities” and will include “explicit comparisons to the current state-of-the-art.” BOOST will bridge the gap between life detection instrument LODs and the LODs required to detect life as part of Ocean Worlds missions. More »