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49th Lunar and Planetary Conference 2018 (LPI Contrib. No. 2083) 1528.pdf

NEW FOR POWERING A SURFACE MISSION ON : CAPTURING ENERGY FROM TITAN’S WINDS FOR SCIENCE EXPLORATION (CETIWISE). M. E. Evans1 and W. J. O’Hara2, 1 Johnson Space Center, Houston, TX, 2KBRWyle, Houston, TX.

Summary: Titan is the largest of  Biology instruments to detect possible micro- with a gravity approximately 1/7 of and an bial in liquid , lakebed sedi- average surface of ~94°K (-180°C) ments or lakeshore near the triple point of [1]. Titan’s at-  Scientific instruments to measure liquid hy- mosphere is four times as dense as Earth’s atmos- drocarbon profiles, meteorology and sub- phere, is composed of ~95% and ~5% surface, geological structures methane, and has a surface one and a half times that of Earth [2]. Extensive on the surface suggest winds (at least sea- sonally) with aeolian transport of sediments [3]. Fluvial systems and /seas of liquid hydrocar- bons with lower viscosity than liquid exist [4]. Exploration of this environment requires technologies capable of surviving cryogenic tem- peratures and liquids. Solar power is not feasible for Titan surface operations due to the persistent haze that blocks the faint . Nuclear powered systems generate waste heat that could envelop an instrument in a methane , or sink a hulled vessel from reduction in buoyant force as the hydrocarbon liquid boils. The goal of this proposal is to develop long lived planetary exploration platforms that operate at extremely cold using re- sources for power, thus eliminating the need for a Figure 1: CETiWiSE Concept surface nuclear power source. We propose explo- ration of the Titan surface by harvesting wind en- Surface Wind Energy Capture: Titan experi- ergy. This proposal has been submit- ences long seasons, diurnal heating, and infre- ted to the NASA Innovative Advanced Concepts quent storms with methane rainfall [1]. A Titan (NIAC) Phase I Step B process in Nov. 2017 with General Circulation Model (GCM) of the near the slogan “going green on an orange moon”. surface environment suggests wind speed thresh- The concept is to develop a Mobile Science olds of 0.4-0.7 m/s at an altitude of 10m [5]. This Platform (MSP) that captures wind energy and proposal includes additional modeling of local- converts it to electricity that is stored in a cryo- ized surface atmospheric winds and lake wave genic superconducting capacitor, then to use the properties as input to the engineering designs. electrical energy to power a suite of instruments, Traditionally, wind energy can be harvested communications equipment, and a propulsion sys- using flexible, rigid, or rotating sails; however, a tem for the MSP (see Figure 1). Alternate propul- rotary sail is desired since it captures wind energy sion systems are proposed for 1) solid surfaces from any direction and drives a generator to cre- with a Ground Rover Base (GRB), 2) liquid sur- ate electricity. The rotating sail also creates a faces with a Lake Vessel Base (LVB), or a combi- “Magnus Effect” propulsive force perpendicular nation of both with an Amphibious Base (AB). to the wind direction [6, 7]. Successful terrestrial This proposal includes many novel and exciting marine applications of rotary sails include the technologies for exploring Titan, including: Flettner Rotor Concept [8-10]. Compared to Earth, the use of a rotary sails on Titan is appeal-  Energy capture from the atmospheric winds ing due to higher atmospheric (more  Cryogenic electrical energy storage using su- force) and lower gravity (less structural weight). perconductive materials 49th Lunar and Conference 2018 (LPI Contrib. No. 2083) 1528.pdf

Cryogenic Electical Energy Storage: AB option includes deployable geological instru- Electrical energy can be stored in a chemical ments to measure surface and subsurface struc- form in a battery, in a magnetic field in an electri- tures with seismometers and a magnetometer. cal coil, or in an electrical field in a capacitor. A Mission Architecture: A solar powered Titan typical, chemical, terrestrial battery requires tem- Orbiter (TO), modeled from the NASA JUNO peratures from -20°C to +100°C with optimum mission, includes relay equipment for communi- performance around 20°C [11]. On cryogenic Ti- cations between the Titan surface and Earth, and tan, batteries are less desirable since they require scientific instruments for surface mapping energy consuming heaters to operate. Below a and atmospheric studies. The planned Space critical temperature, Tc, certain materials will ex- Launch System (SLS) lifts assets from Earth and hibit zero electrical resistance [12]. Recent ad- delivers the TO and one to Titan orbit. vances in materials have identified “high tempera- The lander is composed of the MSP on a propul- ture” superconducting ceramic oxides with a Tc at sion platform, which could be a GRB (for solid 127°K. On the Titan surface at 94°K, supercon- surfces), the LVB (for liquid surfaces), or an AB ducting wires in a coil configuration could sup- (for both solid and liquid surfaces). The lander port a persistent current thus storing energy in the descends through the with a parachute resultant magnetic field. Superconducting wire and captures wind energy to charge batteries for can also be used to create a direct drive electrical MSP deployment, which then captures surface generator eliminating mechanical rotational com- wind energy to power the scientific instruments ponents and . These techniques have been and propulsion platform. The minimum mission demonstrated at colder temperatures [13, 14] and design life is 5 Titan days (80 total Earth days). will be investigated with new “high temperature” References: [1] Oleson, S.R., R.D. Lorenz, superconducting wire types for the Titan surface. and M.V. Paul, (2015), NASA/TM 2015-218831, Biology Surface Instruments: A common [2] Grotzinger, J., et al., (2013), Comparative Cli- organic molecule in Titan atmosphere could be a matology of Terrestrial , [3] Malaska, source of biologic energy for microbial life in sur- M.J.L., et al., (2016), Icarus, 270, 183-196, [4] face hydrocarbon lakes [15]. The MSP includes a Stofan, E.R., et al., (2007), , 445(7123), spectrometer atop the rotary sails to search for 61, [5] Hayes, A., et al., (2013), Icarus, 225(1), color changes in the nearby surface as an indica- 403-412, [6] Kornei, K., (2017), http://www.sci- tor of possible microbial blooms [16]. The propul- encemag.org/news/2017/09/spinning-metal-sails- sion system delivers the MSP to the possible could-slash-fuel-consumption-emissions-cargo- bloom location. Once there, the robotic arm (de- ships, [7] Scientia, (2017), https://www.freed- signed to function in cryogenic temperatures) cap- awn.co.uk/scientia/2015/07/23/what-is-the-mag- tures liquid or solid samples and places them in a nus-effect-and-how-does-it-work/, [8] De Marco, new instrument. This instrument, based on the A., et al., (2016), International Journal of Rotat- ISS mini-DNA sequencer [17], can identify polar- ing Machinery, 2016, [9] Pearson, D., (2014), ity in repetitive patterns indicating the presence of Proceedings of the Influence of EEDI on Ship De- a charged particle “backbone”. This “backbone” sign Conference), [10] Kuuskoski, J., (2017), have been suggested as a potential marker for Norsepower rotor sail solution, [11] CADEX identification of [15, 18, 19]. Battery University, (2017), http://batteryuniver- Other Surface Science Instruments: The sity.com/learn/, [12] Onnes, H.K., (1911), Comm. MSP also includes camera equipment and meteor- Phys. Lab. Univ. Leiden, 122, 124, [13] Chen, H., ology insturments for measuring atmospheric et al., (2009), Progress in Natural Science, 19(3), temperature, pressure, humidity, winds and pre- 291-312, [14] Cao, (2011), in Wind Turbines. cipitation. The LVB and AB option includes InTech, [15] McKay, C., (2016), Life, 6(1), 8, [16] oceanography instruments to measure bathyme- Thurman, H.V., et al., (2011), Essentials of try, liquid surface waves and currents, liquid oceanography, [17] Wallace, S., (2017), NTRS chemical and physical profiles at depth, and a JSC-CN-39208, [18] McLendon, C., et al., sediment grabber to capture samples from the (2015), , 15(3), 200-206, [19] Ben- lake floor for biological analysis. The GRB and ner, S.A., (2017), Astrobiology, 17(9), 840-851