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

Supplementary Cost Slide

www.lpi.usra.edu/opag/TitanEnceladusBillionDollarBox.pdf