Astronomy [MISSION COVERAGE] Huygens

Discussion in 'Astronomy' started by JcMinJapan, Nov 25, 2004.

  1. JcMinJapan

    JcMinJapan Premium Member

    I have seperated this from Cassini as this will be a mission in itself. This is a wonderful explanation of what will be happening as Huygens descends onto the surface of Titan. this is by far the best read that I have come across. This will give everyone a good idea of what will happen and what can be learned. I will add more information as it becomes available for this mission.

    Parachuting through smog to Saturn's moon
    Ron Cowen

    On Jan. 14, a flying saucer will parachute through the thick orange haze of a distant moon's atmosphere. Descending through the hydrocarbon smog, the probe could crash into an icy mountain, plop in a pool of organic goo, or dive into a methane ocean. Welcome to Saturn's largest moon, Titan, a place where organic chemistry appears to be a carbon copy of the infant Earth's just before life got a foothold. The saucer-shaped Huygens probe, named for the 17th-century Dutch astronomer who discovered Titan, has been riding piggyback on the Cassini spacecraft since it left Earth in October 1997. The craft arrived at Saturn on June 30 and has now embarked on a 4-year tour of the planet and its moons.

    Titan has fascinated researchers for 6 decades, ever since astronomer Gerard Kuiper analyzed sunlight reflecting off the moon and discovered methane in its atmosphere. But interest escalated in 1980, when the Voyager 1 spacecraft revealed that methane is a small but key component of a nitrogen-rich atmosphere too thick to see through. The craft also confirmed the presence of ethane, acetylene, propane, and other hydrocarbons. Bombarded by energetic charged particles from Saturn as well as by ultraviolet light from the sun, methane breaks down in Titan's upper atmosphere to form this complex array of organic compounds.

    The chemicals may even rain out of the atmosphere to form hydrocarbon ponds or vast lakes on the moon's surface. Molecules that evaporate from these liquid reservoirs would end up back in the atmosphere, replenishing the supply, just as water in Earth's oceans resupplies our planet's atmosphere.

    That would make Titan, the second-biggest moon in the solar system (after Jupiter's moon Ganymede), the only one with liquid at its surface. Radar beamed from Earth suggests that radio waves are indeed reflecting off a Titan lake or ocean, but results from visible-light studies are less clear-cut.

    Yet even if Huygens doesn't plunge into a methane bath, its findings are likely to make quite a splash.

    It isn't just Titan's mix of organic compounds that intrigues planetary scientists. The moon also has reserves of frozen water that occasionally melt when struck by comets. The overall chemical cocktail appears to offer researchers the only available glimpse of conditions like those on Earth just before life got started. On our planet, traces of this long-ago era have been erased by the actions of life itself. But Titan, residing in the chilly outer solar system and protected by a thick atmosphere, may have preserved for billions of years the conditions that were necessary for life to begin.

    Life is unlikely to have sprung up on Titan, which has an average temperature of –180°C. In exploring the moon, "we're trying to understand about the origin of life in the solar system, which is very different from searching for life," says Larry Soderblom of the U.S. Geological Survey in Flagstaff, Ariz. Titan could reveal how the raw materials for life—organic compounds—collected into pockets of varying concentrations, where biological action could begin, he adds.

    "Titan is more like the prebiotic Earth than any other site in the solar system," asserts planetary scientist Jonathan I. Lunine of the University of Arizona in Tucson.

    Prepare to dive

    Before Huygens can take the big plunge, it will have to execute the big escape—separating from its mother craft, Cassini. On Christmas Day, engineers will radio a final set of commands for the parting. Explosive bolts will fire, springs will give a gentle push to the probe, and Huygens will coast into space. A device on Cassini will twirl Huygens as it detaches, giving the probe a spin of seven revolutions per minute that will prevent it from tumbling end over end.

    During Huygens' 22-day coast to Titan, all the detectors on the probe will be asleep. But three quartz clocks will continue to operate, set to power up the detectors 45 minutes before Huygens reaches the top of Titan's extended atmosphere. The moon's atmosphere reaches to a height of 600 kilometers, or 10 times the height of Earth's.

    While Huygens sleeps, Cassini will fire its engines, reorienting itself so it will pass over Titan at a relatively slow speed during the probe's descent. That's crucial because Cassini is the only relay for the precious data to be collected by the parachuting probe.

    Huygens' suite of instruments will have only a few hours to record data. Once it hits the atmosphere, it will take about 2.5 hours to descend to the surface. Whether the probe survives the landing depends on the surface it encounters. Huygens wasn't designed as a lander, but if it falls into liquid, it may float for a while.

    Even if it survives impact, the battery-operated craft will have no more than about 2 hours to study the surface after it's landed. By that time, Cassini will have disappeared over the horizon of the landing site, continuing on its tour of the Saturn system.

    Down to work

    The 319-kilogram probe packs six sophisticated instruments that will attempt to measure in different ways the basic properties of Titan's atmosphere: its temperature, pressure, wind speed and direction, and composition.

    The Huygens Atmosphere Structure Instrument (HASI) will kick in early, beginning at an altitude of 2,000 km. Accelerometers will measure how rapidly the probe slows down from its initial speed of 6 km per second. That deceleration will indicate gas density and wind gusts in these upper reaches of the atmosphere.

    During the initial, rapid descent, the searing heat beneath Huygens will make temperature measurements of the atmosphere impossible. But once the parachute opens, at a height of 170 km above Titan, a thermometer on HASI will be put to work.

    HASI will also explore the electrical conductivity of Titan's atmosphere. Titan lacks the magnetic shield that protects Earth from galactic cosmic rays, which are energetic enough to ionize gas molecules. Titan's atmosphere is much more highly charged and conductive than that of Earth.

    HASI also carries a microphone that can listen to the sounds of Titan—such as thunder—as the probe falls. If this device succeeds, Titan will be one of the few places beyond Earth where sound has been recorded.

    Relying on an ultrasteady radio signal from Huygens to Cassini, the Doppler Wind Experiment (DWE) will measure the strength of Titan's wind. As winds buffet the parachuting probe to and fro, the radio signal detected by Cassini will shift between slightly higher and lower frequencies. This Doppler shift will indicate wind speed to an accuracy of a meter per second.

    The gas chromatograph/mass spectrometer (GCMS) will measure the composition of the atmosphere in two ways. One instrument sorts molecules by weight and the other, by chemical reactivity. If Huygens manages to land intact on Titan, the GCMS will also measure the composition of the solids or liquids it encounters on the moon's surface. To accomplish that feat, the device will be heated just before impact so that it vaporizes the first surface material with which it comes into contact. Hasso Niemann of NASA's Goddard Space Flight Center in Greenbelt, Md., who built the device, also designed a simpler, spectrometer-only instrument that successfully parachuted into Jupiter in 1995 (SN: 12/23&30/95, p. 420).

    A related instrument on Huygens, the aerosol collector and pyrolyser, will suck Titan's atmosphere through a filter and heat the trapped particles in miniature ovens. Twice during the descent, the vaporized samples will be piped to the GCMS.

    Say cheese

    Only one group of instruments on Huygens will graphically document the exploration. The descent imager/spectral radiometer (DISR) will take both visible-light and near-infrared pictures, beginning at 150-km altitude and continuing down to the surface, where its cameras will resolve features just a few centimeters across. As the spinning probe descends, the series of images will form overlapping panoramic views that scientists can covert into stereo pictures, providing a three-dimensional perspective of Titan.

    DISR's visible-light and infrared spectrometers will analyze the feeble sunlight reflected from the surface of Titan back through its atmosphere, revealing the composition of clouds and the size of aerosol particles. As Huygens descends to an altitude of 700 meters, DISR will switch on a 20-watt lamp that will illuminate the surface, enabling the spectrometer to analyze the reflected light.

    Mounted on the underside of the probe, the surface-science package (SSP) is the primary tool for studying the nature of the landing site. Because the craft's survival after impact is highly uncertain, researchers have designed the SSP so that it can begin its exploration of Titan near the top of the atmosphere, 2.5 hours before touchdown.

    Using a high-frequency signal generator and receiver, the SSP will attempt to measure the speed of sound at different altitudes in Titan's atmosphere. At each altitude, the sound speed indicates the composition of the atmosphere, notes John Zarnecki of the Open University in Milton Keynes, England, who helped design the European-built instrument.

    Using two devices akin to carpenter's levels, the SSP will record the tilt of the probe as it plunges through the atmosphere as well as Huygens' final orientation on the ground. The tilt during descent indicates the strength of the wind buffeting the probe, complementing more-precise measurements by the DWE.

    On the surface, the amount of tilt may indicate whether Huygens has landed on solid ground or is bobbing on an ocean, rocked by waves that could be as high as 15 m. Measuring the frequency of such waves "would be the first time we've conducted an experiment in oceanography" on a place other than Earth, says Zarnecki.

    The SSP also comes equipped with an acoustic sounder, similar to sonar, that can send signals down through the atmosphere and listen for an echo. Should Huygens pass through an extremely dense methane cloud, the reflected signal could reveal the condensation of methane droplets, or rain. As Huygens comes within a few hundred meters of the surface, the echo may indicate the bumpiness of the terrain. If the probe lands in a lake or an ocean, an echo may reveal the depth of the reservoir.

    By aiming a light beam into any substantial body of liquid ethane or methane, the SSP will attempt to record the index of refraction of the fluid, another indication of its density.

    A short carbon fiber protruding from the probe's underbelly will be the first part of Huygens to strike the surface. Four sensitive transducers connected to the tip of the stick will detect the force of impact, indicating whether the landing site is solid, gooey, or liquid.

    The SSP also includes a miniature float, like a fishing bobber. In the event of a liquid landing, the portion of the float sticking out of the lake or ocean will indicate the fluid's density.

    Several times during the years when he and colleagues were designing and testing the SSP, they questioned why they were putting so much effort into a device that might last only 3 minutes on Titan's surface, he recalls.

    "Still, today, if you offered me 3 minutes to explore the surface of Titan, I would grab it," Zarnecki says. "We all want to know what the composition of this stuff is."

    Says Huygens researcher William Borucki of NASA's Jet Propulsion Laboratory in Pasadena, Calif.: "The idea in back of all our minds, with each of these instruments, is to try to understand conditions that might make it possible for life to emerge."

    "We're mad to undertake this venture at all, but at least we're not completely mad," says Zarnecki.
  2. Mizar

    Mizar Premium Member

    hyugens merge

  3. JcMinJapan

    JcMinJapan Premium Member

    hyugens merge

    Hyugens is set to be released, this is very good news. I have also read that it will be woken up a few hours early to ensure that we recieve all the data. For me, this will be the biggest thing that NASA has done. We will get to finally see a planet with an atmosphere. There is no telling what we may or may not see. Coule we see live creatures? Will we see oceans? This is what exploration is all about. Although I think Mars is interesting, I do not find it as fascinating as Titan. I am dreaming wildly and hoping to see some movement on the surface! Finally get to see a LIVE planet. I will be watching NASA TV for the next few weeks.
  4. Mizar

    Mizar Premium Member

    Hrmmm And I thought I wasn't geting anything for christmas...
  5. Mizar

    Mizar Premium Member

    Carolina Martinez (818) 354-5011

    Jet Propulsion Laboratory, Pasadena, Calif.

    STATUS REPORT: 2004-296 December 24, 2004

    Cassini MissionStatus Report

    The European Space Agency's Huygens probe successfully detached from NASA's Cassini orbiter today to begin a three-week journey to Saturn’s moon Titan. NASA's Deep Space Network tracking stations in Madrid, Spain and Goldstone, Calif., received the signal at 7:24 p.m. (PST). All systems performed as expected and there were no problems reported with the Cassini spacecraft.

    The Huygens probe, built and managed by the European Space Agency, was bolted to Cassini and has been riding along during the nearly seven-year journey to Saturn largely in a "sleep" mode. Huygens will be the first human-made object to explore on-site the unique environment of Titan, whose chemistry is assumed to be very similar to that of early Earth before life formed. Huygens will tell us whether this assumption is correct.

    "We wish to congratulate our European partners as their journey begins and wish them well on their descent to Titan," said Robert T. Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are very excited to see the probe off and to have accomplished this part of our job. Now we’re ready to finish our part – receiving and relaying the Huygens data back to Earth."

    "Today’s release is another successful milestone in the Cassini-Huygens odyssey,” said Dr. David Southwood, director of science program for the European Space Agency. “This was an amicable separation after seven years of living together. Our thanks to our partners at NASA for the lift. Each spacecraft will now continue on its own but we expect they’ll keep in touch to complete this amazing mission. Now all our hopes and expectations are focused on getting the first in-situ data from a new world we’ve been dreaming of exploring for decades."

    The Huygens probe will remain dormant until the onboard timer wakes it up just before the probe reaches Titan's upper atmosphere on Jan. 14, 2005. Then it will be begin a dramatic plunge through Titan's murky atmosphere, tasting its chemical makeup and composition as it descends to touch down on its surface. The data gathered during this 2-1/2 hour descent will be transmitted from the probe to the Cassini orbiter. Afterward, Cassini will point its antenna to Earth and relay the data through NASA's Deep Space Network to JPL and on to the European Space Agency's Space Operations Center in Darmstadt, Germany, which serves as the operations center for the Huygens probe mission. From this control center, ESA engineers will be tracking the probe and scientists will be standing by to process the data from the probe's six instruments.

    On Monday, Dec. 27, the Cassini orbiter will perform a deflection maneuver to keep it from following Huygens into Titan's atmosphere. This maneuver will also establish the required geometry between the probe and the orbiter for radio communications during the probe descent.

    More information on the Cassini-Huygens mission is available at: and .

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter. The European Space Agency built and managed the development of the Huygens probe and is in charge of the probe operations. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini's science instruments.
  6. junior_smith

    junior_smith Premium Member

    I'm really interested in thsi one, I found it interesting how little we know about titan though, we dont know if it will have hydrocarbon lakes (because it is right around the temperature when methane becomes a liquid, but they have found complex hydrocarbons in the atmosphere of titan) or if they will land on a mountain or even slush! I really hope this one goes well i think Nasa needs a big success, and i think they are going to get it here
  7. Hazlenuttt

    Hazlenuttt New Member

    I recently have taken an Astronomy class and I was fascinated by the fact that Titan had such a thick atmosphere for being a moon of a Jovian planet. In my class, the book we used was partically interested in the possibility if not factual evidence that Titan has ethane oceans..and if true..there could in fact be unusual life forms living beneath these oceans... Yet, this is just a step by step process and I am glad that you are keeping the news in check..Thanks..:yes:
  8. junior_smith

    junior_smith Premium Member

    yeah thats what i was talking about with the chemical oceans, because there temp is so close to the liquid point of a hydrocarbon (whether it be ehtane or methan) they cant really tell if its going to be a chemical lake or if it is just going to be in the atmosphere
  9. JcMinJapan

    JcMinJapan Premium Member

    I came across this picture today on NASA. This is a great view of the expected happenings sureing the descent. I cannot wait for this!!!!!
  10. JcMinJapan

    JcMinJapan Premium Member

    Huygens will be arriving at Titan very shortly!
    You can watch live commentary on NASA TV at 3: 00 am on the 14th.

    It will be 5pm here in Japan, so I will keep all updated on anything live here on ID!
  11. oddtodd

    oddtodd Premium Member

    YEP ! just read 10 AM pacific that images will be here on terra-firma ! This is the kind of investigative space research I like . Not some fool hardy , premature idea about men (and women) investigating planets in person .

    Can't fix it here so it's : " runaway....runaway...." (Just an oppinion)

    Science rocks !
  12. JcMinJapan

    JcMinJapan Premium Member

    Radio astronomers confirm Huygens entry in the atmosphere of Titan

    14 January 2005
    The Robert C. Byrd Green Bank Telescope (GBT) of the National Radio-astronomy Observatory in West Virginia, USA, a part of the global network of radio telescopes involved in tracking the Huygens Titan probe, has detected the probe's 'carrier' (tone) signal.

    The detection occurred between 11:20 and 11:25 CET, shortly after the probe began its parachute descent through Titan's atmosphere. The extremely feeble signal was first picked up by the Radio Science Receiver supplied by the NASA Jet Propulsion Laboratory. This signal is an important indication that the Huygens probe is 'alive'. However, it does not contain yet any substance; the latter is expected to come a few hours later via the Cassini spacecraft.
    What the Green Bank radio telescope has detected is only a ‘carrier’ signal. It indicates that the back cover of Huygens must have been ejected, the main parachute must have been deployed and that the probe has begun to transmit, in other words, the probe is ‘alive’. This, however, still does not mean that any data have been acquired, nor that they have been received by Cassini. The carrier signal is sent continuously throughout the descent and as such does not contain any scientific data. It is similar to the tone signal heard in a telephone handset once the latter is picked up.

    Only after having received the data packets at ESOC will it be possible to say with certainty whether data were properly acquired. The first data set from Cassini will reach ESOC in the afternoon. Additional downlinks will follow throughout the evening and night for redundancy.

    Further analysis of the signals will be conducted using other three independent data acquisition systems at the Green Bank Telescope. In addition to the GBT, sixteen other radio telescopes in Australia, China, Japan and the USA are involved in tracking the Huygens probe.

    The ultimate goal of the tracking experiment is to reconstruct the probe's descent trajectory with an unprecedented accuracy of the order of one kilometre. The measurements will be conducted using Very Long Baseline Interferometry (VLBI) and Doppler tracking techniques. This would enable studies of the dynamics of Titan's atmosphere, which is considered to be a 'frozen' copy of that of the early Earth.

    The VLBI component of the tracking experiment is coordinated by the Joint Institute for VLBI in Europe (JIVE) and ESA; the Doppler measurements are conducted by the Jet Propulsion Laboratory.
  13. JcMinJapan

    JcMinJapan Premium Member

    8:30 update on NASA TV

    There is very good news. The latest news is.....

    The probe should have landed on the surface about 30 minutes ago. The probe is on the surface and is still sending data ok. They are only recieving the wind data currently.

    The Cassini data will start to send the more detailed data in a few hours from now. The surface science package was the first part to land.

    They are talking about the science packages, but it does not seem, to give too much other information as to what has been found yet.
  14. JcMinJapan

    JcMinJapan Premium Member

    First Huygens pics....
  15. Seth Bullock

    Seth Bullock Premium Member

    Pics are very interesting JC. I can't wait to see what they find next!
  16. Bleys

    Bleys Phoenix Takes Flight Staff Member

  17. helenheaven

    helenheaven Premium Member