THEO concept mission: Testing the Habitability of Enceladus’s Ocean

Abstract

Saturn's moon Enceladus offers a unique opportunity in the search for life and habitable environments beyond Earth, a key theme of the National Research Council's 2013-2022 Decadal Survey. A plume of water vapor and ice spews from Enceladus's south polar region. Cassini data suggest that this plume, sourced by a liquid reservoir beneath the moon's icy crust, contain organics, salts, and water-rock interaction derivatives. Thus, the ingredients for life as we know itliquid water, chemistry, and energy sources-are available in Enceladus's subsurface ocean. We have only to sample the plumes to investigate this hidden ocean environment. We present a New Frontiers class, solar-powered Enceladus orbiter that would take advantage of this opportunity, Testing the Habitability of Enceladus's Ocean (THEO). Developed by the 2015 Jet Propulsion Laboratory Planetary Science Summer School student participants under the guidance of TeamX, this mission concept includes remote sensing and in situ analyses with a mass spectrometer, a sub-mm radiometer-spectrometer, a camera, and two magnetometers. These instruments were selected to address four key questions for ascertaining the habitability of Enceladus's ocean within the context of the moon's geological activity: (1) How are the plumes and ocean connected? (2) Are the abiotic conditions of the ocean suitable for habitability? (3) How stable is the ocean environment? (4) Is there evidence of biological processes? By taking advantage of the opportunity Enceladus's plumes offer, THEO represents a viable, solar-powered option for exploring a potentially habitable ocean world of the outer solar system.

Enceladus as a potential oasis for life: Science goals and investigations for future explorations

“…Flythroughs may be targeted at different altitudes, different times in the orbital period, or over different tiger stripes (e.g. MacKenzie et al 2016). The importance of the latter was recently further demonstrated by Hedman et al (2018) who used data from Cassini UVIS and VIMS to show that the dust/gas ratio varies between tiger stripes.…”

Rapid Mission Concept Development at the 2019 Caltech Space Challenge: A Small Lander Network Studying the Habitability of Enceladus

“…For SILENUS to follow planetary protection measures, the orbiter must be destroyed at the end of the mission to avoid any contact with Enceladus or other regions of interest. Drawing from the proposed mission "Testing the Habitability of Enceladus's Ocean" (THEO) [3], we proposed to crash the orbiter into Tethys, a nearby moon that has been previously determined to be inhospitable to life. It was this decision, combined with the self-imposed budgetary constraints set by team Voyager, which the judges deemed enough to grant our team the winning proposal.…”

A Post-Newtonian Gravitomagnetic Effect on the Orbital Motion of a Test Particle around Its Primary Induced by the Spin of a Distant Third Body

“…As a consequence, they are the natural targets of several concept studies and proposals for dedicated missions to them, including also orbiters (Razzaghi et al 2008;Spencer & Niebur 2010;MacKenzie et al 2016;Verma & Margot 2018;Sherwood et al 2018). Since, at present, sending a spacecraft to Europa seems more likely than to Enceladus, as it can be learnt at https://europa.nasa.gov/about-clipper/overview/ and http://sci.esa.int/juice/ on the Internet, we investigated in a little more detail this potentially appealing Jovian scenario, even if it is not said that the actually approved missions will finally involve the use of an orbiter.…”