Mission to Titan Mitchell Drew and Mariel Henkoff
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3701
Saturn• Orbital Radius:– 1.43 * 109 km
• (Average) Radius:– 58,232 km
• Mass:– 5.68 * 1026 kg
• Core of rock and ice• Metallic, liquid, and gaseous hydrogen layers – Gaseous layer also contains helium
• Magnetosphere shields planet, rings, and moons• 62 Moons
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3379
Meet Titan
• Largest of Saturn’s Moons by far
• Radius: 2600 km• Mass: 1.34 * 1023 kg• Orbit: 1 * 106 km– 16 day orbit
• Tidally lockedhttp://photojournal.jpl.nasa.gov/catalog/PIA10487
So what’s so special about Titan?• Titan’s atmosphere
kept it a mystery for centuries – Christiaan Huygens:
1655– Voyager 1– Hubble
• Cassini Mission– Only known moon with
dense atmosphere– Only known body
besides Earth with stable liquids on surface
http://apod.nasa.gov/apod/ap041028.html
Titan Earth
Atmosphere •1.5 bar•N2, CH4, H2
•Stratified
•1 bar•N2, O2, H2O, CO2
• Stratified
Surface •~ -179° C •Mountains, river channels •Lakes: liquid methane •Frozen H2O crust•Mounds of hydrocarbon sand dunes
•~ 14° C•Mountains, rivers, lakes •Surface oceans: liquid water• Hard silicate crust
Interior •Suspected ocean 100 km below surface: liquid H2O + ammonia•Cryovolcanism and out gassing (methane)•Crust Movement?
•Solid inner core, liquid outer core, solid, viscous mantle, solid crust •Volcanism and out gassing of CO2
•Plate Tectonics
Hydrological Cycle
•Clouds•Methane rain•Huge impact on landscape
•Clouds •H2O Rain•Frequent precipitation
Methane vs. Water
•Surface temperature close to triple point of methane
•Surface temperature close to triple point of water•Water is highly soluble
http://www.chicagospace.org/cassini_saturn.html
http://apod.nasa.gov/apod/ap070207.html
http://www.astrobio.net/pressrelease/3720/ice-volcanoes-on-titan
http://www.space.com/11550-saturn-moon-titan-underground-ocean.html
Cassini Mission:New Questions and Objectives
• Primary mission launched in 1997, arrived in 2004, extended until 2017
• Piqued Interests in Titan– Seasonal changes – Varying surface composition– Interior: liquid mantle, crust
movement, magnetic field– Atmospheric structure, weather
activity– Hydrogen question: incompatible
hydrogen ratios at surface and in atmosphere• Sunlight splits Methane and Nitrogen
in upper atmosphere and their atoms recombine to form organic compounds – Net yield of Hydrogen
http://vims.artov.rm.cnr.it/doc/img.html
http://photojournal.jpl.nasa.gov/catalog/PIA12810
Significance of Hydrogen Depletion
• Observed processes are consistent with the idea of life
• Unexplainable discrepancies between Hydrogen in upper atmosphere and in lower atmosphere/surface– Hydrogen can easily move through and escape
from the atmosphere– Hydrogen has a long lifetime– Also a lack of predicted acetylene
Methane
• Gaseous Methane – atmosphere
• Liquid Methane – Surface lakes– Hydrological Cycle
• Question of presence of methane– Broken in upper atmosphere
by sunlight– Concentration is maintained
with no explainable source– Cryovolcanism?
http://www.scientificamerican.com/article.cfm?id=lets-go-sailing-on-lakes-of-titan-2009-11
Life on Titan?• Proposed alternative form of
life– Methane based– Solubility of methane is less
than water• Accommodations by life could
include large surface to volume ratios and active transport
• Could explain hydrogen depletion and methane production– Consume hydrogen like oxygen– Consume acetylene like
glucose – Produce methane like carbon
dioxidehttp://www.badmovies.org/movies/brainarous/
http://autocww.colorado.edu/~toldy2/E64ContentFiles/VirusesMoneransAndProtists/Amoeba.html
Cassini-Huygens• Huygens Probe– Transmitted
information for 2.5 hours while descending through atmosphere
– ~70 minutes on surface
http://www.esa.int/esaMI/Cassini-Huygens/SEMLSRN2UXE_1.html
Proposed Mission• 2008: Europa vs. Titan – Equal promise of scientific study– Europa was chosen - mission was easier and less risky;
included only an orbiter – Europa life would be similar to oceanic Earth life
• Titan holds very different possibilities for scientific discovery– Life would be exotic– Similar chemical processes as those on Earth exist,
but under extremely different conditions
Our Mission
• Two parts– Blimp– Amphibious rover
• Transport– 7 year trip to Titan– Spacecraft with simple
cruise stage• Drop off blimp and
rover• Cost – 2.5 Billion
http://www.space.com/1189-outer-planet-palooza-europa-titan-missions-support.html
http://en.wikipedia.org/wiki/File:Duck_Tour_boat_beaching.JPG
Our MissionBlimp
• Objectives– Sample atmosphere
• Gas chromatograph and mass spectrometry • Tunable diode laser
– Scan and map surface • Cameras, radar altimeter
– Observe climate and weather differences• Meteorology instruments
• Design: Aerobot– Transmitter to Earth, receiver for rover– Life span 1-1.5 years, possibly longer– Power: Radioisotope Thermoelectric Generator (MMRTG)
• Applications to life theory– Accurate measure of hydrogen concentration differences– Measure of methane concentrations to locate sources
Our MissionRover
• Criteria– Withstand atmospheric pressure, extreme cold and weathering;
float on liquid methane• Objective - Explore surface hydrocarbons and liquid
methane– Understanding of solid and liquid surface composition – 3
months• Probe• Mass spectrometry• Chemical analysis • Seismometer – liquid subsurface ocean? Cryovolcanism?
– Ongoing observations– Search for life components
• Catalysts or unidentifiable compounds• Microscopic and Macroscopic imaging
Our MissionRepercussions
• Environmental contamination• Damage to landscape– Avoid rover dying in lake
• Disruption of atmosphere– From gases in blimp, skewed results from leaked
gas
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