# 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 organic compounds in Titan's atmosphere, raising the possibility of life on Titan. 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.
On July 22, 2006, the Cassini-Huygens probe conducted a flyby of Titan, passing at a distance of 148,000 km. The 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 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 However, the proposal was superseded in a 2012 vote by the InSight lander, which was tasked with studying Mars' core.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 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. It will also be equipped with a sampler to collect samples of lakebed minerals and liquid methane and ethane hydrocarbons from Titan's water. Additionally, a camera will be attached to the front of the vessel.

## Scientific goals

The submarine is will aid scientists in refining models and simulations of undersea activity on Titan. It will contribute to the detection of elemental and chemical properties of the water, as well as undersea rocks and minerals. Additionally, it may help identify undersea seismic activity on Titan. The submarine will also collect data on the depth and temperature of specific locations within Titan’s lakes.
Additionally, theories propose the existence of a global subsurface ocean beneath Titan's surface. The mission aims to enhance understanding of subsurface oceans and explain the dramatic shifts in Titan's surface features. It may also provide insights into the impact of subsurface oceans on the geology beneath and above Titan's seas.
During certain parts of the mission, the submarine will partially emerge from the liquid hydrocarbons to study Titanian weather, tides, coastlines, and the unsolved observation surrounding disappearing islands or icebergs on Titan.

## Instruments
### 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)