Unlike NASA, which has much more financial resources.European Space AgencyEuropean Space Agency (ESA) must be pragmatic in its choice of missions to explore and observe the universe. However, throughout its history, its selections have proven successful in many areas. Space exploration bears witness to these achievements, especially after the incredible adventure of Rosetta and its fly lander. GiottoGiotto And waiting for its Halley comet flyby and the ExoMars rover, but also with the technological and scientific feat achieved in January 2015: the landing of the Huygens probe on Titan, the world’s largest moon. SaturnSaturn Then known very badly.
This historic event in the field of research RoboticsRobotics International Day is celebrated regularly, and today we commemorate the 20th.e On January 14, 2005, the mission’s anniversary, after a journey of more than 3 billion kilometers that began on October 15, 1997, the Huggins landed on Titan’s surface.
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Titan, Saturn’s largest moon, is shrouded in a thick layer of haze that not only reflects sunlight but also makes its surface impossible to see in visible wavelengths.
As much a feat as it is scientific.
Huygens’ achievement transcends technology. Although the probe developed by Thales Elenia Space was designed to withstand extreme conditions. TitanTitanWith temperatures around -200°C, no one on Earth could have predicted the day before landing whether the mission would be successful. However, everything went perfectly: from hibernation to waking up SeparationSeparation Along with Cassini, its descent throughEnvironmentEnvironment Landing on Titan and its terrain with unknown features and the nature of its soil (lakes, rock, snow, etc.), the probe landed gently and operated for more than three hours after its arrival, collecting previously unpublished data and Moved.
Notably, mission managers believed that Hudgens would only be able to operate on Earth for 30 minutes. Yet it survived its descent and landing so well that it continued to transmit information for more than three hours. Unfortunately, not all of the data could be transmitted to the Cassini probe which, from a distance of 60,000 km, delivered them to Earth. When Cassini passed below the horizon, the probe lost contact. to harm
Huygens’ achievement is also of great scientific importance. Despite the loss of data from Earth, data collected during the Cassini Huygens mission revealed that Titan’s surface is a world shaped by cryovolcanism. rainrain Methane and others HydrocarbonsHydrocarbons. Measurement of ConductivityConductivity The atmosphere carried out by Huygens, combined with information transmitted by Cassini, shed light the lightthe light A rich landscape: lakes and seas of methane and ethane, huge dunes of SableSableAmmonia water under rivers, ice slabs, and an ocean The crystThe cryst Everyone bathes in the snowy environment. argonargon and propylene.
The descent of the Huygens probe to Titan.
The floor is assigned to Patrice Kozin (Thales Elenia Space), Huygens’ head of avionics in 1990 until firing in 1997, then systems manager from 1997 to 2005.
Patrice Cozen: Only one atmospheric model was defined – the Lelouch-Huntin model – derived from observations of the Voyager 1 probe during this time. HooverHoover of Titan in 1980, and included surviving only 3 minutes on Earth after 150 minutes of atmospheric descent.
The European Space Agency recognized this “lightness” of specifications with an agreement with Aerospatial (now Thales Alenia Space). Scientists then worked throughout the program to refine the specifications of Titan’s atmosphere as seen by Huygens. The matterThe matter Icing electricityelectricitytriboelectricity, bursts of take outtake outSurface reflection…
“First a note, Huygens was a “descent probe”, not a “lander”.“
Futura: What safety margins were in place to ensure the success of the Huygens landing on Titan?
Patrice Cozen: One of the first to comment, Huygens was ” Descent probe “, no” LanderLander ».
In addition to temperatures of -180°C, the unknown of what the surface might be like made it simply impossible to explain the “landing”. Of course, all mechano-thermal elements and ParachuteParachute The temperature, in terms of aerothermodynamic flow, was designed for even more extreme cases. pressurepressure Dynamic… The most critical events of the mission – the awakening of the probe after 22 days of hibernation, the detection of the moment of parachute deployment – were based on triple redundancy and included backup. In addition, all commands were sent by two computers working in parallel. Adapted to the environment it encountered.AccelerometerAccelerometerMeasurement of rotation and height of the probe relative to the surface.
Futura: Would Huygens have been able to float if he had landed on a hydrocarbon lake or another liquid surface on Titan?
Patrice Cozen: Yes! A study during development showed that this was possible for a while, although the probe was never designed!
Futura: What technologies were developed specifically for the Huygens probe and later reused in other space missions?
Patrice Cozen: These are mainly technologies related to re-entry into the atmosphere and thermal protection during parachute.
Regarding the thermal shield, the experience gained on Huygens has made it possible to adopt another thermal protection for exploration activities. He flew on Beagle-2, and on ExoMars 2016’s Schiaparelli (on that mission, we know he did his job well!).
As for the Huygens parachute, it was also used on Beagle-2, with a similar parachute design and manufactured by the same company. ExoMars has the same design. tools DigitalDigital Predictions have evolved, but they all come from Huygens’ developments. The experiment also made it possible to define the necessary material selection and aging tests for space travel, especially NylonNylon etc KevlarKevlar.
As for the Huygens structure, the sizing criterion was again used. ExoMarsExoMars.
“This international cooperation enabled today’s most ambitious interplanetary missions“
Futura: What are the major legacies and contributions of the Huygens mission to space exploration?
Patrice Cozen: Huygens’ legacy is a new and brilliant demonstration of expanding the boundaries of space exploration. It is above all a reference, a model in terms of high-level cooperation on science between the major space agencies: ESA, NASA and ASI. This cooperation enabled today’s most ambitious interplanetary missions. ESA and NASA have also been “dreaming” of repeating this collaboration for 20 years!
Futura: Are there plans for a Huygens 2 mission? What might it look like and what goals might it achieve?
Patrice Cozen: A Huygens 2 would have to “land” of course, but it would also have to be able to “pass” Titan, as Cassini-Huygens had detected a surface made up of dunes, craters, hydrocarbon lakes, plains, reliefs, river networks. Shows great diversity. To address many outstanding questions related to this surface: What is the composition of the surface elements? what ChemistryChemistry PrebioticPrebiotic Does it happen there? What is the composition of lakes? How old is the surface?
This vehicle, to survive on Titan, must be equipped with an RTG and be able to transmit its data directly or indirectly. orbitorbit Around Titan
Futura: Could NASA’s Dragonfly be “Huygens 2”?
Patrice Cozen: In fact, to a certain extent, we can say yes. The Dragonfly mission, currently in development, meets many of the criteria that can be attributed to “Huygens 2,” as I described earlier. That said, it is also relevant to consider the possibilities that the “Huygens 3” mission could offer!
