Timothy Titus's research while affiliated with United States Geological Survey and other places

Publications (12)

Article
Dwarf planet Ceres is a compelling target for future exploration because it hosts at least regional brine reservoirs and potentially ongoing geological activity. As the most water-rich body in the inner solar system, it is a representative of a population of planetesimals that were likely a significant source of volatiles and organics to the inner...
Article
On Earth and throughout our solar system, ripples and dunes in sand and dust offer insights into how winds blow, liquid currents flow, and solid particles fly and bounce over the terrain.
Article
Full-text available
Plain Language Summary For 2 decades, planetary scientists have had many ideas about how and when very long, narrow gullies formed on frost‐affected sand dunes on Mars. First, it was thought that they were remnant features left behind millions of years ago when the climate may have supported a wetter environment. Then, repeat imagery showed that gu...
Article
Terrestrial caves offer scientific and engineering insights and serve as testing grounds for future forays by humans and robots into caves on other worlds. https://eos.org/science-updates/planetary-cave-exploration-progresses
Article
Full-text available
The transport of H2O ice along the retreating north polar seasonal CO2 ice cap has previously been modeled and observed. Spectral observations show that H2O ice forms on the interior of the seasonal cap, while thermal observations show these regions to be consistent with CO2 ice. Prior to the sublimation of the seasonal CO2, the observed H2O ice de...

Citations

... In the aftermath of the Dawn mission, lander missions have been proposed; due to the low gravity, even sample return missions are feasible. An interesting concept is proposed by Castillo-Rogez, Brophy, et al. (2022), in form of a electrically propulsed orbiter that is able to land and relaunch as a whole, returning samples to Earth. The mission is supposed to collect samples of carbonate salts as well as the darker reference surface materials and return it to Earth at ≤ 20°C to prevent alteration. ...
... This is likely due to a lack of high-quality surface data acquired since the Magellan mission, which ended in 1994. With the selection of three new missions to Venus, NASA's VERITAS and DAVINCI and ESA's EnVision missions, this dearth of quality surface observations will be resolved, and the full extent of Venusian dunes may finally be unmasked (Titus et al., 2021). ...
... Nonetheless, decades of orbital and in situ exploration have highlighted the geologic diversity of Mars. A program of measurements at the Martian surface at multiple sites is necessary to enable the step change in answering these scientific questions about Mars' evolution and search for life (e.g., Dehant et al., 2012;Diniega et al., 2021;Edwards et al., 2021;Ehlmann et al., 2016Ehlmann et al., , 2017aNiles et al., 2012;Rafkin et al., 2009;Wray, 2012). Different places on the surface record different processes and different time slices of Mars' four billion year history (Figure 1.1; Appendix A.2). Lessons from the study of our own Earth highlight the importance of exploring multiple sites to understand and distinguish the influence of both local and global phenomena, and that learning about planetary processes requires integrative study of the rock and ice record across time and space. ...
... Before sending a robotic mission [15] or astronauts to a specific lava tube, it would be desirable to scout and map several locations. Mars helicopters are candidate platforms to scout multiple lava tubes throughout a single mission. ...
... There are several reasons for the interest in these underground features in space exploration and research ( [11], [12]). Subsurface cavities are shielded from radiation, micrometeorite bombardment, and particle implantation, along with having more stable thermal conditions ( [13]). ...
... Defrosting spots and flows similar to those seen at high latitude (Section 5.1) also occur, generally preceding the larger morphologic changes (e.g., Gardin et al., 2010). Small-scale defrosting spots associated with sublimating CO 2 appear around the Russell crater dune gullies from around L S = 105-205° and develop into flows (Dinwiddie & Titus, 2021;Jouannic et al., 2019). ...
... From a planetary perspective, detecting caves elsewhere in the solar system will factor prominently into how caves are targeted for future robotic exploration in the search for life [27][28][29][30][31]. Advanced detection capabilities will also enable us to prioritize caves for human habitation on the Moon and Mars [29,[32][33][34], and searching for evidence of life on Mars [29,34]. ...
... Visible solar radiation can 967 penetrate the CO2 ice layer and, via a process known as the solid state greenhouse effect (Matson 968 and Brown, 1989) Although not yet well characterized through observations or models, it is likely that H2O and 999 CO2 frost/ices do not form and evolve independently of each other and that their interplay, and 1000 interaction with incorporated atmospheric dust, constitutes an additional control on 1001 geomorphological activity that is not yet well understood. For example, CO2 ice can serve as a 1002 sink for water vapor (Houben, 1997;Houben et al., 1997), and H2O deposits affect basal 1003 sublimation of CO2 (Titus et al., 2020). In addition to influencing accumulation and sublimation 1004 timing and rates, mechanical interactions between different types of frost/ice may create another 1005 control on some geomorphological activity. ...