Thursday, August 27, 2009

White Paper: Technology Development for In Situ Titan Exploration

Many of the Decadal Survey White Papers focus on specific missions or area of scientific investigation. However, missions can fly and conduct science only if the technologies required are available. One paper, "Technologies for Outer Planet Missions" lists a the technology investments needed to enable the post Jupiter Europa Exploration of the outer planets. It covers everything from aerocapture (to enable a Neptune mission), to advanced batteries, and in situ instruments. This is the absolutely necessary yeoman work necessary to enable planetary exploration.

Two sections of the white paper focuses on technology development necessary for future in situ Titan exploration. Reading these sections suggests that these concepts need technological maturation before they will be ready to fly. However, these paragraphs also give an idea of the types of missions that might be flown once the technology is ready (budgets permitting).

Previous studies have identified the montgolfière balloon as a key element in a comprehensive Titan exploration strategy with very high science value. The most recent 2008 joint NASA/ESA Titan Saturn System Mission (TSSM) study provided a compelling concept for implementation of a montgolfière at Titan. While orbiter and lander elements appear to have significant flight heritage, a balloon has not been flown on Titan and will require focused study and risk reduction efforts. Based upon the high priority of Titan science, results from many years of mission studies, and current state of technology readiness, NASA and ESA review boards have recommended the following be pursued to enable a balloon mission at Titan within foreseeable budgets and at acceptable risk: 1) conduct focused studies of Titan balloon mission options, leveraging from previous work, to focus on selection of architecture(s) that best achieve highest priority science and 2) initiate substantial sustained investment in risk reduction efforts needed to mature the Titan balloon concept for flight readiness. Risk reduction efforts include the following: balloon deployment and inflation, thermal performance margins, packaging and thermal management inside the aeroshell, interface complexity between balloon, RPS and aeroshell and integration of the RPS into the balloon.
Additionally, long-term operation of mobile platforms would be faced with challenges because of the long latency in communications, communications blackouts due to Titan rotation and occlusion by Saturn, the absence of a magnetic field, low surface illumination conditions, and the lack of high-resolution orbital maps. Consequently, autonomous navigation and control and autonomous onboard science capabilities for data prioritization and opportunistic observations will be critical. Linking scientific observations to their coordinates on Titan would significantly enhance the science value of an in situ mission. OPAG recommends a sustained investment in this decade that would result in the demonstration of technical readiness for launch of a Titan balloon mission. Further OPAG recommends that NASA fund the development of key autonomy capabilities required for a Titan balloon.

The geological, geophysical and presumed geochemical diversity of Titan’s surface suggest at least three surface types that should be sampled by a future mission to Titan: 1) a Titan lake lander/submersible that would land on a Titan sea e.g. Kraken Mare to measure the soluble hydrocarbon, nitrile, and noble gas content, isotopic composition and determine the lake level 2) a dune lander that could determine the interior structure, subsurface characteristics and tidal deformation as well as the composition of the dunes in hopes of understanding the fate of Titan’s organic aerosols that constantly rain down on the surface, and 3) a lander positioned near suspected cryo-volcanic structures to make seismic measurements and to follow the evolution of organic chemistry anticipated when Titan organic aerosols are exposed to liquid water. In all cases, the objectives involve geophysical measurements as well as sampling and analytical chemistry in a cryo-environment. Furthermore, the lake lander/submersible and the cryo-volcanic lander would require unique designs for such planetary environments. OPAG recommends that NASA invest in focused studies of these lander concepts and mature the technologies required to fulfill the science requirements.

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