Titan Mare Explorer
is a proposed spacecraft lander
A lander is a spacecraft which descends toward and comes to rest on the surface of an astronomical body. For bodies with atmospheres, the landing is called atmospheric reentry and the lander descends as a re-entry vehicle...
that, if launched, would probe Titan
Titan , or Saturn VI, is the largest moon of Saturn, the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....
, the largest moon of the planet Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
, and would perform the first exploration of an extraterrestrial sea. TiME has been proposed to NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
by Proxemy Research as a scout-like pioneering mission, originally as part of NASA's Discovery & Scout Mission Capability Expansion (DSMCE) concept-study program. TiME is one of three Discovery Mission finalists that received US$3 million in May 2011 to develop a detailed concept study. After another review in 2012, NASA will pick one to see through to launch. The selected mission will be cost-capped at $425 million, not including launch vehicle funding.
It has also been proposed to delay TiME enough so it can be incorporated into the flagship-Titan Saturn System Mission
Titan Saturn System Mission was a joint NASA/ESA proposal for an exploration of Saturn and its moons Titan and Enceladus, where many complex phenomena have been revealed by the recent Cassini–Huygens mission...
proposed for launch in the 2020s
The 2020s or "twenty twenties" is the decade that will begin on January 1, 2020 and will end on December 31, 2029. It is the third decade of the 21st century and the 3rd millennium.-Notable predictions and known events :...
TiME is a low-cost, outer-planet mission that would directly measure the organic constituents
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
on Titan and would perform the first nautical
Seamanship is the art of operating a ship or boat.It involves a knowledge of a variety of topics and development of specialised skills including: navigation and international maritime law; weather, meteorology and forecasting; watchstanding; ship-handling and small boat handling; operation of deck...
exploration of an extraterrestrial sea, analyze its nature and, if possible, a shoreline.
The discovery on 22 July 2006 of lakes and seas in Titan's northern hemisphere confirmed the hypothesis that liquid hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s exist on it. In addition, previous observations of southern polar storms and new observations of storms in the equatorial region provide evidence of active methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
-generating processes, possibly cryovolcanic features from the interior of Titan.
It is believed that Titan's methane cycle is analogous to Earth's hydrologic cycle, with meteorological working fluid existing as rain, clouds, rivers and lakes. TiME would directly discern the methane cycle of Titan and help understand its similarities and differences to the hydrologic cycle on Earth. The Principal Investigator of the lander mission is Ellen Stofan, a member of the Cassini radar team. The spacecraft concept is being developed by Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
, Proxemy Research Inc., and the Applied Physics Laboratory
The Johns Hopkins University Applied Physics Laboratory , located in Howard County, Maryland near Laurel and Columbia, is a not-for-profit, university-affiliated research center employing 4,500 people. APL is primarily a defense contractor. It serves as a technical resource for the Department of...
at Johns Hopkins University
The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...
TiME's launch would be with an Atlas 411
Atlas is a family of U.S. space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics, to be used as an intercontinental ballistic missile...
rocket during 2016 and arriving to Titan in 2023. The target lake is Ligeia Mare
Ligeia Mare is a lake located on Titan, the planet Saturn's largest moon. It is bigger then Lake Superior on Earth. It is composed of liquid hydrocarbons located at 79.0° N, 248.0° W, measuring roughly 500km in diameter and with surface area of about ~100,000km2...
(78°N, 250°W). It is one of the largest lakes of Titan
The Lakes of Titan, a moon of Saturn, are bodies of liquid ethane and methane that have been detected by the Cassini–Huygens space probe, and had been suspected long before. The large ones are known as maria and the small ones as lacūs .-History:The possibility that there were hydrocarbon seas on...
identified to date, with a surface area of about ~100,000 km². The backup target is Kraken Mare
Kraken Mare is the largest known body of liquid on the surface of Saturn's moon Titan. It was discovered in 2007 by the Cassini probe and was named in 2008 after the Kraken, a legendary sea monster....
The Titan Mare Explorer would undergo a 7-year simple interplanetary cruise with no flyby science. Measurements and data transmissions would begin only after splashdown
Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by American manned spacecraft prior to the Space Shuttle program. It is also possible for the Russian Soyuz spacecraft and Chinese Shenzhou spacecraft to land in water, though this is only a contingency...
. The science objectives of the mission are:
Malin Space Science Systems
- Determine the chemistry of a Titan sea. Instruments: Mass Spectrometer (MS), Meteorology and Physical Properties Package (MP3).
- Determine the depth of a Titan sea. Instrument: Meteorology and Physical Properties Package (Sonar) (MP3).
- Constrain marine processes on Titan. Instrument: Meteorology and Physical Properties Package (MP3), Descent and surface cameras.
- Determine how the local meteorology over the sea varies on diurnal timescales. Instrument: Meteorology and Physical Properties Package (MP3), cameras.
- Characterize the atmosphere above the sea. Instrument: Meteorology and Physical Properties Package (MP3), cameras.
Malin Space Science Systems is a San Diego, California company that designs, develops, and operates instruments to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Michael C. Malin....
, which builds and operates camera systems for spacecraft, has signed an early development contract with NASA to conduct preliminary design studies. There would be two cameras. One would take pictures during the descent to the surface of Ligeia Mare lake, and the other would take pictures after landing.
Titan's thick atmosphere rules out the use of solar panels like the ones that have kept the Mars rovers and landers functioning for years, while batteries would only provide some hours of power at most. If selected by NASA, the TiME lander would be the test flight of the new Advanced Stirling Radioisotope Generator
The Advanced Stirling Radioisotope Generator is a radioisotope power system using Stirling power conversion technology currently being developed under joint sponsorship by the United States Department of Energy and NASA for potential future space missions...
(ASRG), which is a prototype meant to provide availability of long-lived power supplies for landed networks and other planetary missions. For this mission, it would be used in two environments: deep space and non-terrestrial atmosphere. The ASRG is a radioisotope power system using Stirling power conversion
A Stirling engine is a heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work....
technology and is expected to generate 140–160 W of electrical power; that is four times more efficient than RTG
A radioisotope thermoelectric generator is an electrical generator that obtains its power from radioactive decay. In such a device, the heat released by the decay of a suitable radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples.RTGs can be...
s currently in use. Its mass is 28 kg and will have a nominal lifetime of 14 years.
- ≥14 year lifetime
- Nominal power : 140 W
- Mass ~ 28 kg
- System efficiency: ~ 30 %
- Two GPHS modules
- Uses 0.8 kg plutonium-238
The lake-lander would not be self-propelled and the wind will be expected to push this buoyant craft around the lake for months.
The vehicle will communicate direct to Earth and, in principle, it could be possible to maintain at least intermittent contact for several years after arrival: the Earth finally sinks below the horizon as seen from Ligeia in 2026. It will not have a line of sight to Earth to beam back more data until 2035.
The capsule is expected to drift on the surface of the lake, pushed by currents and wind with typical speeds of 0.5 m/s, and not exceeding 1.3 m/s (4.2 feet/second). Even if the vehicle's motion cannot be controlled, location sequences can be used to optimize scientific return, such as lake depth, temperature variations and shore imaging. Some proposed location techniques are measurement of Doppler shift, Sun height measurement, and Very Long Baseline Interferometry
Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...
Potential habitable zone
The chance to discover a form of life
Whether or not there is life on Titan, the largest moon of Saturn, is at present an open question and a topic of scientific discussion and research....
with a different chemical basis than life on Earth has led some researchers to consider Titan the most important world on which to search for extraterrestrial life
Extraterrestrial life is defined as life that does not originate from Earth...
. A few scientists hypothesize that if the hydrocarbon chemistry on Titan crossed the threshold from inanimate matter to some form of life, it would be difficult to detect. This is because there is no way that terrestrial life could have originated or could prosper on Titan because of the fundamentally different chemistry of Titan's surface. Moreover, because Titan is so cold, the amount of energy available for building complex biochemical structures is limited, and any water-based life would freeze without a heat source.