Titan Submarine



Titan Submarine is a proposed NASA submarine probe that will visit Saturn’s largest moon Titan, and will plausibly explore either Kraken Mare or Ligeia Mare, two of Titan’s largest lakes. The concept was proposed by Steven Oleson, Ralph Lorenz, and Micheal Paul, technical experts at NASA’s Glenn Research Center in Ohio.

History
In early 2005, studies conducted by the Cassini-Huygens probe revealed an abundance of organic compounds in Titan’s atmosphere, raising the possibility of extraterrestrial life existing or forming. Despite not being located within the habitable zone, methane in cold environments must reach its critical temperature to coalesce into methane ions. Huygens’s descent on Titan in 2005 provided significant data about Titan’s atmosphere. During its 2-hour descent, Huygens supplied scientists with information suggesting a functioning climate system, water cycle, and the presence of organic matter and molecules. Due to these conditions, scientists propose that thermal heating from these compounds could create conditions conducive to the emergence of life on Titan.

Alternate theories suggest the presence of a global subsurface ocean beneath Titan’s surface. If confirmed, the Titan Submarine mission could provide scientists with valuable insights, analogous to those gained from studying moons like Europa and Enceladus, which also possess icy shells covering potential subsurface oceans.

On July 22, 2006, the Cassini-Huygens probe conducted a flyby of Titan, passing at a distance of 148,000 km. This remarkable flyby revealed methane lakes on Titan's surface, providing evidence of the existence of liquid water, a hypothesis first suggested in 1995 following a Hubble Space Telescope observation of Titan.

As a result of these studies and discoveries, NASA’s Institute for Advanced Concepts proposed the Titan Mare Explorer. However, the proposal was superseded in a 2012 vote by the InSight lander, which was tasked with studying Mars' core. However, both the Titan Mare Explorer and the Titan Submarine projects remain active under the auspices of NIAC.

The Titan Submarine initiated Phase I in 2014 and transitioned to Phase II, dubbed Titan Turtle, in November 2020. The Titan submarine is still under development and refinement of new technologies by NASA’s Institute for Advanced Concepts.

Overview
The submarine will be carried into space aboard an Atlas V rocket, accompanied by an unmanned Boeing X-37, which is designed to withstand the atmospheric conditions of Titan.

The Titan Submarine will be equipped with radioisotope rockets, a type of thermal rocket that uses decaying radioactive elements, to propel the submarine for longer durations on Titan while conserving power on the probe. Radioisotope rockets utilize isotopes such as polonium-210 or plutonium-238, both of which have a half-life of approximately 80 years or more. It will also be equipped with a sampler to collect samples of lakebed minerals and potentially liquid methane and ethane hydrocarbons from Titan's water. Additionally, a camera will be attached to the front of the vessel. During certain parts of the mission, the submarine will partially emerge from the water to study Titanian weather, tides, coastlines, and the mystery surrounding disappearing islands or icebergs on Titan.

Scientific goals
The submarine will aid scientists in refining models and simulations for undersea activity on Titan. Additionally, it will assist in detecting elemental properties within undersea rocks or minerals, as well as potentially identifying undersea earthquakes on Titan. Furthermore, it will provide data on the depth and temperature of specific spots within certain lakes on Titan.

Instruments
The submarine will be equipped with scientific instruments to help understand Titan's lakes.

Instrument list

 * Liquid samplers
 * Surface imager
 * Depth sounder
 * Weather sounder
 * Side-scan sonar arrays

Interior instruments

 * Command and data handling
 * Communications
 * Altitude determination and control

Proposed instruments

 * Seafloor sample analyzer
 * Ventral imager

Energy
The submarine will be equipped with 840 W of:
 * Isotope power systems
 * Stirling radioisotope generator
 * 2 eight-GPHS SRG (chosen as the baseline power system proving 900 W of DC power)

Further information

 * YouTube video gives an illustration on how the variety of instruments on board the submarine work.