Titan Saturn System Mission
Encyclopedia
Titan Saturn System Mission (TSSM) 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. With an estimated NASA cost of $2.5 Billion (FY07), TSSM was proposed to launch in 2020, get gravity assists from Earth and Venus, and arrive at the Saturn system in 2029. The 4-year prime mission would include a two-year Saturn tour, a 2-month Titan aero-sampling phase, and a 20-month Titan orbit phase.
(EJSM) proposal for funding since then, however in February 2009 it was announced that NASA/ESA had given EJSM priority ahead of TSSM, although TSSM will continue to be studied for a later launch date, probably sometime in the 2020s. Detailed assessment reports of the mission elements as well as a specific concept for a lake landing-module called Titan Mare Explorer
(TiME) with the potential of becoming a part of the TSSM have been released in February and October 2009, respectively.
The TSSM mission consists of an orbiter
and two Titan exploration probes: a montgolfière (hot air balloon) that will float in Titan's clouds, and a lander
that will splashdown
on one of its methane
seas.
Both probes’ data are to be relayed to a Titan orbiter. They will be equipped to study Titan’s features with instruments for imaging, radar
profiling, and surface as well as atmospheric sampling
, much more complete than done by the Cassini–Huygens mission.
The spacecraft will use several gravity assist flyby
s of other planets to enable it to reach Saturn. The baseline design envisaged a September 2020 launch, followed by four gravity assists (Earth
-Venus
-Earth-Earth), and arrival at Saturn 9 years later in October 2029. This is one of several available Earth-to-Saturn transfer options from the year 2018 through 2022. Current NASA-plans do not give the TSSM a priority, however, and it is unlikely any of the proposed launch dates can be met.
Upon Saturn arrival, in October 2029, the orbiter’s chemical propulsion system would place the flight system into orbit around Saturn, followed by a two year Saturn Tour Phase, characterized by the deployment of the in situ elements, and including a minimum of seven close Enceladus flybys and 16 Titan flybys. During this period, repeated satellite gravity assists and manoeuvres will reduce the energy needed to insert into Titan's orbit. As the craft completes its flyby by Enceladus, the orbiter will analyze the unusual cryovolcanic plumes at the moon's south pole.
The montgolfière, a hot air balloon, would be released on approach to the first Titan flyby for ballistic entry into Titan's atmosphere for its six Earth months’ mission from April 2030 to October 2030. Based on Cassini–Huygens discoveries, the montgolfière should be able to circumnavigate Titan at least once during its nominal lifetime at its deployment latitude
of about 20°N, 10 kilometers above Titan's surface.
Numerous proposals have been brought forward with respect to the lake-lander concept. One of the most detailed plans so far is the so called Titan Mare Explorer
(TiME), which has originally been proposed as a separate scout mission, but might eventually be postponed and included in the TSSM. If approved, TiME would be released by the orbiter on its second Titan flyby. Due to Titan's haze layer and its distance to the Sun, the lander cannot be powered by solar panels and it will rely on the new Advanced Stirling Radioisotope Generator
(ASRG), which is a prototype meant to provide availability of long-lived power supplies for landed networks and other planetary missions. The lander will be targeted to Ligeia Mare
, a northern polar sea of liquid hydrocarbons at about 79°N. The probe will descend by parachute, like the Huygens probe
of 2005. A few hours later, it will splashdown on the liquid surface; this would be the first floating exploration of an extraterrestrial sea. The plutonium-powered craft’s principal function is to sample and analyze organics on the surface for a period of about 3 to 6 months, including 6 hours of atmospheric descent.
At Titan, the science goals would be to provide information on such aspects as the composition of the surface and the geographic distribution of the various organic constituents; on the methane
cycle and the methane reservoirs; on the ages of the surface features, and in particular on whether cryovolcanism and tectonism are actively ongoing or are relics of a more active past; on the presence or absence of ammonia
, of a magnetic field
and of a sub-surface ocean; on the chemistry that drives complex ion formation in the upper atmosphere; and on a large altitude range in the atmosphere, from 400–900 km, which remains poorly explored after Cassini. In addition, much remains to be understood about seasonal changes of the atmosphere at all levels, and the long-term escape of constituents to space.
TiME lander would splashdown
on Ligeia Mare
, a methane
sea on Titan's northern hemisphere. It is believed that Titan’s methane cycle is analogous to Earth’s hydrologic cycle, with meteorological working fluid existing in liquid and gas phase. TiME would directly discern the methane cycle of Titan and help understand its similarities and differences to the hydrologic cycle on Earth. However, questions about the sources of re-supply of methane to the atmosphere remain to be answered. This world is built by organic activities which still operate and Cassini/Huygens findings suggest a world with a balance of geologic and atmospheric processes that is the solar system’s best analogue to Earth
. Moreover, an interior ocean discovered by Cassini, deep underneath Titan’s dense atmosphere and surface is thought to be largely composed of liquid water. TSSM would be the first mission in the 50 years of space exploration, where an extensive and interdisciplinary in situ survey of active organic chemistry and climate on the land, on the sea, and in the air of another world will take place.
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...
/ESA proposal for an exploration of Saturn
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 its moons Titan
Titan (moon)
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....
and Enceladus
Enceladus (moon)
Enceladus is the sixth-largest of the moons of Saturn. It was discovered in 1789 by William Herschel. Until the two Voyager spacecraft passed near it in the early 1980s very little was known about this small moon besides the identification of water ice on its surface...
, where many complex phenomena have been revealed by the recent Cassini–Huygens mission. With an estimated NASA cost of $2.5 Billion (FY07), TSSM was proposed to launch in 2020, get gravity assists from Earth and Venus, and arrive at the Saturn system in 2029. The 4-year prime mission would include a two-year Saturn tour, a 2-month Titan aero-sampling phase, and a 20-month Titan orbit phase.
Origin and status
The Titan Saturn System Mission (TSSM) was officially created in January 2009 by the merging of the ESA's Titan and Enceladus Mission (TandEM) with NASA's Titan Explorer 2007 study, although plans to combine both concepts date at least back to early 2008. TSSM was competing against the Europa Jupiter System MissionEuropa Jupiter System Mission
The Europa Jupiter System Mission – Laplace was a proposed joint NASA/ESA unmanned space mission slated to launch around 2020 for the in-depth exploration of Jupiter's moons with a focus on Europa, Ganymede and Jupiter's magnetosphere...
(EJSM) proposal for funding since then, however in February 2009 it was announced that NASA/ESA had given EJSM priority ahead of TSSM, although TSSM will continue to be studied for a later launch date, probably sometime in the 2020s. Detailed assessment reports of the mission elements as well as a specific concept for a lake landing-module called Titan Mare Explorer
Titan Mare Explorer
Titan Mare Explorer is a proposed spacecraft lander that, if launched, would probe Titan, the largest moon of the planet Saturn, and would perform the first exploration of an extraterrestrial sea...
(TiME) with the potential of becoming a part of the TSSM have been released in February and October 2009, respectively.
Mission overview
Orbiter
An orbiter is a space probe that orbits a planet.-Asteroids:*NEAR Shoemaker...
and two Titan exploration probes: a montgolfière (hot air balloon) that will float in Titan's clouds, and a lander
Lander (spacecraft)
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 will splashdown
Splashdown (spacecraft landing)
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...
on one of its methane
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...
seas.
Both probes’ data are to be relayed to a Titan orbiter. They will be equipped to study Titan’s features with instruments for imaging, radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
profiling, and surface as well as atmospheric sampling
Sample (material)
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, or a material not countable as individual items. Samples of countable...
, much more complete than done by the Cassini–Huygens mission.
The spacecraft will use several gravity assist flyby
Flyby
Flyby may refer to:* Flypast or flyover, a celebratory display or ceremonial flight* Planetary flyby, a type of interplanetary spacecraft mission* Gravity assist, a spaceflight maneuver* "Fly by II", a single released by the UK band Blue...
s of other planets to enable it to reach Saturn. The baseline design envisaged a September 2020 launch, followed by four gravity assists (Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
-Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
-Earth-Earth), and arrival at Saturn 9 years later in October 2029. This is one of several available Earth-to-Saturn transfer options from the year 2018 through 2022. Current NASA-plans do not give the TSSM a priority, however, and it is unlikely any of the proposed launch dates can be met.
Upon Saturn arrival, in October 2029, the orbiter’s chemical propulsion system would place the flight system into orbit around Saturn, followed by a two year Saturn Tour Phase, characterized by the deployment of the in situ elements, and including a minimum of seven close Enceladus flybys and 16 Titan flybys. During this period, repeated satellite gravity assists and manoeuvres will reduce the energy needed to insert into Titan's orbit. As the craft completes its flyby by Enceladus, the orbiter will analyze the unusual cryovolcanic plumes at the moon's south pole.
The montgolfière, a hot air balloon, would be released on approach to the first Titan flyby for ballistic entry into Titan's atmosphere for its six Earth months’ mission from April 2030 to October 2030. Based on Cassini–Huygens discoveries, the montgolfière should be able to circumnavigate Titan at least once during its nominal lifetime at its deployment latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
of about 20°N, 10 kilometers above Titan's surface.
The lake-lander
Titan Mare Explorer
Titan Mare Explorer is a proposed spacecraft lander that, if launched, would probe Titan, the largest moon of the planet Saturn, and would perform the first exploration of an extraterrestrial sea...
(TiME), which has originally been proposed as a separate scout mission, but might eventually be postponed and included in the TSSM. If approved, TiME would be released by the orbiter on its second Titan flyby. Due to Titan's haze layer and its distance to the Sun, the lander cannot be powered by solar panels and it will rely on the new Advanced Stirling Radioisotope Generator
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. The lander will be targeted to Ligeia Mare
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...
, a northern polar sea of liquid hydrocarbons at about 79°N. The probe will descend by parachute, like the Huygens probe
Huygens probe
The Huygens probe was an atmospheric entry probe carried to Saturn's moon Titan as part of the Cassini–Huygens mission. The probe was supplied by the European Space Agency and named after the Dutch 17th century astronomer Christiaan Huygens....
of 2005. A few hours later, it will splashdown on the liquid surface; this would be the first floating exploration of an extraterrestrial sea. The plutonium-powered craft’s principal function is to sample and analyze organics on the surface for a period of about 3 to 6 months, including 6 hours of atmospheric descent.
Science goals and objectives
The major goals of the TSSM mission can be summarized under four categories:- Explore Titan as a system
- Study Titan’s organic inventory and astrobiological potential
- Constrain Titan’s origin and evolution models
- Recover information on Enceladus and Saturn’s magnetosphereMagnetosphereA magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
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...
cycle and the methane reservoirs; on the ages of the surface features, and in particular on whether cryovolcanism and tectonism are actively ongoing or are relics of a more active past; on the presence or absence of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, of a magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
and of a sub-surface ocean; on the chemistry that drives complex ion formation in the upper atmosphere; and on a large altitude range in the atmosphere, from 400–900 km, which remains poorly explored after Cassini. In addition, much remains to be understood about seasonal changes of the atmosphere at all levels, and the long-term escape of constituents to space.
TiME lander would splashdown
Splashdown (spacecraft landing)
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...
on Ligeia Mare
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...
, a methane
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...
sea on Titan's northern hemisphere. It is believed that Titan’s methane cycle is analogous to Earth’s hydrologic cycle, with meteorological working fluid existing in liquid and gas phase. TiME would directly discern the methane cycle of Titan and help understand its similarities and differences to the hydrologic cycle on Earth. However, questions about the sources of re-supply of methane to the atmosphere remain to be answered. This world is built by organic activities which still operate and Cassini/Huygens findings suggest a world with a balance of geologic and atmospheric processes that is the solar system’s best analogue to Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. Moreover, an interior ocean discovered by Cassini, deep underneath Titan’s dense atmosphere and surface is thought to be largely composed of liquid water. TSSM would be the first mission in the 50 years of space exploration, where an extensive and interdisciplinary in situ survey of active organic chemistry and climate on the land, on the sea, and in the air of another world will take place.
See also
- Cassini–Huygens
- Exploration of SaturnExploration of SaturnThe exploration of Saturn has been solely done by robotic probes. Like all gas giants, there is no solid surface for a solid probe to land on. Most missions therefore have been flybys, although the Cassini–Huygens spacecraft is currently in orbit....
- Kronos (spacecraft)Kronos (spacecraft)Kronos is a proposed mission to Saturn. It is aimed at detailed study of the chemical composition of the Saturn's atmosphere, gravity and magnetic fields. The proposal consists of the solar powered carrier spacecraft, two atmospheric probes and two small probes for the close-up imaging of the...
- Lakes of TitanLakes of TitanThe 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...
- TiME (spacecraft)