MISSION TO BRIGHTON On Christmas day 2004 the Huygens probe detached from the Cassini mothercraft to begin its journey to the surface of Saturn’s most mysterious moon, Titan. On board is the Open University’s payload – designed to examine Titan's surface. In this virtual mission you’ll discover the key-hole view through which Huygens scientists will be examining this alien landscape. But our journey will be a little closer to home. In this website you are going to learn all about how scientists use the tiniest glimpse of data to work out a picture of a planet - and how easy it is to get it wrong. Here you have a chance to get a "probe-eye view" of the Huygens probe as it sits on a planetary surface. Find out all about the instrumentation and science behind the recent Titan expedition, then have a go at your very own scientific mission! All photographs and illustrations are copyright ESA unless otherwise stated. Overview The Cassini-Huygens spacecraft was launched in 1997 on a mission to Saturn and Titan. The mission is made up of two separate elements: the mothercraft, the Cassini orbiter which will orbit Saturn for four years, and the Huygens probe, which detached from the main craft on the 25th December 2004 to begin its descent to the mysterious moon, Titan. Titan is Saturn's largest moon and is bigger than the planet Mercury. This strange world fascinates scientists because it is the only moon in our solar system to have a dense atmosphere. Little is known about this moon, which is why scientists are so keen to have a look. Scientists at the Open University have been part of the team developing the Huygens probe. They've developed a number of ingenious instruments that will hopefully give us a better sense of what makes up the surface of Titan. Caption: The Cassini-Huygens spacecraft was launched on the 15th October 1997, on board a Titan IV-Centaur rocket at Cape Canaveral Photo: ESA/NASA Our Mission Here at Open2 we wanted to give you an experience of how to interpret the data from these instruments. However, early on we discovered the obvious: we don't have the 250 million pounds to send our own probe to Titan. So we're going to send three virtual probes over somewhere a little easier to get to - Brighton! On our Mission to Brighton you can be the scientist. Readings from the instruments will help you find out about the surface properties, topography and movement of the probe once it's landed. But we've got to warn you, the instrumentation is now seven years old and we've got our fingers crossed that nothing breaks down and the mission is a success. Caption: Our mission takes us to the exotic location of a British seaside town: Brighton. Photo: BBC Titan - A Strange Place Titan is the largest of Saturn's 33 known satellites. It is the only satellite in our Solar System to have a dense atmosphere, which is mostly made up of nitrogen and methane. These gases were probably captured by Titan long ago from the gas cloud from which the Solar System formed. Part of the fascination in studying Titan is that the Earth's original atmosphere may once have been like this. A smog of 'organic' molecules, made by solar ultraviolet radiation causing methane molecules to link together into chains, hides the surface from view except using special techniques. It also means that the surface may contain lakes of liquid ethane and methane and/or patches of tarry scum. Don't believe anyone who tells you that Titan would smell terrible, because without a space suit the cold temperature (-180 degrees Centigrade) and lack of oxygen would kill you before you could take a sniff. Another misconception is that all the methane and ethane makes Titan's atmosphere 'inflammable', but this too is wrong because these gases won't burn in the absence of oxygen. Caption: A haze layer can be clearly seen around Titan. Photo: NASA/JPL/Space Science Institute. Titan facts and figures Titan compared to other bodies: Titan: Radius 2575 km; Surface Temperature -180 ºC; Mass (relative to Earth) 0.022 Density (g per cubic cm) 1.88. Earth: Radius 6378 km; Surface Temperature 15 (ºC); Mass (relative to Earth) 1; Density (g per cubic cm) 5.52. The Moon: Radius 1738 km Surface Temperature 1 (ºC); Mass (relative to Earth) 0.0123 Density (g per cubic cm): 3.34. Ganymede: (largest satellite of Jupiter): Radius 2631 km Surface Temperature -160 (ºC); Mass (relative to Earth) 0.0181; Density (g per cubic cm): 1.83. Mercury: (largest satellite of Jupiter): Radius 4878    km Surface 170  (ºC); Mass (relative to Earth) 0.0181; Density (g per cubic cm): 5.43. Caption: This artist's illustration shows Titan's surface with Saturn dimly in the background through Titan's thick atmosphere of methane, ethane and (mostly) nitrogen. The Cassini spacecraft flies over the surface. Image: ESA/David Seal Titan facts and figures Composition: Core - rocky, maybe with an iron inner core. Mantle and crust - ice (mostly frozen water but mixed with frozen methane and other ices). Surface - possible lakes and rivers of liquid ethane, solid icy surfaces may be covered in scum or 'goo' made of complex, tarry, organic molecules. Thus, the Huygens lander had to be designed to survive landing on either a solid or a liquid surface. Atmosphere - surface pressure 1.5 bar, composition nitrogen 94%, methane 6%, plus traces of ethane, acetylene, diacetylene, methylacetylene, cyanoacetylene, propane, carbon dioxide, cyanogens, hydrogen cyanide and helium. Caption: Titan in ultraviolet and infrared wavelengths, this image was taken during a fly-by on 26th October 2004 Image: NASA/JPL/SSI Titan discovery Titan was discovered in 1655 by the Dutch astronomer Christiaan Huygens, after whom the Titan landing probe is named. To Huygens, Titan was simply 'the moon of Saturn', and it did not get its present name, proposed by John Herschel, until 1847. Caption : Christiaan Huygens. Image: ESA Titan seen by Pioneer 11 The Pioneer 11 spacecraft, launched on the 5th April 1973 was the first spacecraft to visit Saturn. It made the first close-up images of Titan in 1979. The spacecraft also took the first close-up views of Saturn, and found that Titan was too cold for life. Titan seen by Voyager The two space probes of NASA's Voyager series flew past Saturn in November 1980 and August 1981. These provided close-up pictures of Titan, but the dense atmosphere prevented any glimpse of the surface. Titan's thick haze layer is shown in this enhanced Voyager 1 image. Courtesy NASA/JPL-Caltech Titan seen by the Hubble Space Telescope Prior to the current Cassini-Huygens mission, the best view of Titan's surface was obtained using the Hubble Space Telescope; from its vantage point above Earth's atmosphere it recorded images at 0.85 to 1.05 micrometres wavelength (near infrared), at which Titan's atmosphere turned out to be partly transparent. Here is a montage of four such images (at ninety degrees rotation), showing bright and dark areas on the surface. The prominent continent-sized bright region has now been named Xanadu Regio. Caption: Image: Peter H Smith and Mark Lemmon of the UA Lunar and Planetary Laboratory, and NASA. Titan seen by Cassini The Cassini probe, which began orbiting Saturn in July 2004, will fly past Titan many times during its nominal five-year mission. Cassini has two ways of seeing Titan's surface. One is to use its Imaging Science Subsystem (ISS) to record images at about 0.938 micrometres, at which wavelength Titan's atmosphere is fairly transparent to light. This is the same trick used by the Hubble Space Telescope but because Cassini is much closer far more detail can be seen. Caption: A mosaic of nine images makes up this view of the mysterious moon. Image: NASA/JPL/Space Science Institute Radar Imaging The other technique is to use radar to construct an image of the surface. On radar images, rough surfaces appear bright and smooth surfaces appear dark. There is no straightforward correspondence with the bright and dark areas on ISS images. The image shown here covers an area about 150 km across. The upper central part contains some narrow, bright, winding lines that may be channels carved by liquid ethane flowing away from the rough (radar-bright) highlands occupying the left-hand half of the picture. Some of the channels appear to discharge into rough (radar-bright) areas that may be debris deposited as the flow fanned out and its strength weakened. The smooth (radar-dark) area in the upper right is possibly a lake. On the other hand, this interpretation could be mostly wrong! Caption: Note the contrast between the smooth and rough edges. Image: NASA/JPL Latest news and pictures Dateline: 28th December 2004 The Cassini spacecraft successfully performed a "getaway" manoeuvre to keep it from following the Huygens probe to the surface of Titan. As the probe has no facility for navigation, the Cassini spacecraft had to take a deliberate collision course with Titan to ensure accurate delivery of the probe. More information from the ESA website http://www.esa.int/SPECIALS/Cassini-Huygens/SEMQW98873E_0.html Caption: The Huygens Probe will enter the upper layers of Titan's atmosphere at 22000 km/h, slowing to about 1400 km/h in less than 2 minutes. Image: ESA-D DUCROS Images from the current mission: http://saturn.jpl.nasa.gov/multimedia/images/index.cfm NASA Jet Propulsion Laboratory http://photojournal.jpl.nasa.gov/mission/Cassini NASA Planetary Photojournal http://www.esa.int/SPECIALS/Cassini-Huygens/index.html ESA Cassini-Huygens Site http://saturn.jpl.nasa.gov/news/press-releases.cfm NASA Cassini-Huygens press releases Data on all Saturn's known satellites: http://nssdc.gsfc.nasa.gov/planetary/factsheet/saturniansatfact.html Saturnian Satellite Fact Sheet General information about Titan: http://www.nineplanets.org/titan.html Nineplanets: Titan http://en.wikipedia.org/wiki/Titan_(moon) Wikipedia: Titan (Moon) Caption: Artist's illustration of Huygens parachuting through Titan's atmosphere. Image: ESA Instrumentation The Surface Scientific Package (SSP) is only part of the instrument suite that is on the Huygens probe. Most of the other instruments are designed to examine Titan's atmosphere in depth. Of course, on our mission we're going to Brighton, not Titan. We already know a substantial amount about the Earth's atmosphere. The SSP instruments are housed at the bottom of the probe in a small section known as the "top hat". The SSP is designed to withstand temperatures of -198 degrees Celsius and has to cope with the possibility of landing on a liquid surface. It's also been designed to be flooded by any surface liquid Caption: Images: ESA. Background: NASA/JPL/SSI Roll your mouse over the instruments to discover the instrument name. Click on the instrument for more information on that instrument Accelerometer External (ACC-E) The accelerometer subsystem is designed to find out what sort of surface the probe lands on. The ACC-E sticks out from the bottom of the Huygens probe and is thrust into any solid surface as the probe lands. It senses the force of impact as it does so and graphs of the readings represent the different surface properties. If the probe lands in liquid, this sensor does not send back any useful information. The force of impact is sensed by a piezoelectric ceramic element that is mounted between the titanium alloy head and the pylon shaft. The ACC-E can distinguish between materials such as fine sands, grits and coarse gravel. When combined with images, the information from this instrument will enable scientists to get a pretty good overview of what the surface is like. Accelerometer Internal (ACC-I) This sensor sits inside the SSP's electronics box, which is not positioned in the "top hat". It's placed elsewhere in the probe because it should not be exposed to liquid. This device provides information about vertical accelerations experienced by the entire probe, and especially how it bounces on and after impact. If the probe strikes a solid surface, this sensor determines the compressive properties of the surface at the probe's impact site. It's designed to cater for two of the most extreme possibilities, an impact with a perfectly stiff solid, and an oblique landing in a fluid body of low density and low viscosity. Acoustic Properties Instrument - Sonar (API-S) This instrument uses sonar to measure the topography of the surface during the final few hundred metres of the probe's parachute descent. It sends out a sound signal with a wavelength of around 13mm and "listens" for its echo. Each echo is sampled at a rate of 1 kHz and during the final part of the descent will provide information about the topography with a precision of around 10cm. If the probe touches down into liquid, this handy instrument may also provide measurements of the depth of the liquid in which it is floating, effectively becoming a depth-sounder. It uses information from the Acoustic Properties Instrument - Velocimeter (API-V) on the speed of sound in the liquid to do this. Acoustic Properties Instrument - Velocimeter (API-V) This instrument is designed to help determine what gases make up the atmosphere and can also identify what (if any) liquid the probe lands in. It does this by measuring the speed of sound. It uses two sensors that transmit and then "listen for" a brief 1 MHz acoustic signal. While the probe descends towards the surface these sensors will operate once a second, giving a detailed profile of the speed of sound in the atmosphere along the probe's trajectory. Other instruments in the probe measure temperature, so the speed of sound will help determine the molecular mass of the atmosphere. This data is an important cross-check for other instruments that measure the make up of the gases in the atmosphere. It also determines the speed of sound through any rain or liquid aerosols. At the surface, if the probe lands in a liquid, it uses the speed of sound to find out what the liquid is. On Titan, this is presumed to be a methane/ethane ocean, on Earth, it's sea water Density Sensor (DEN) The "top hat" containing the Surface Scientific Package in the Huygens probe is designed to be flooded by any liquid that it lands in. This sensor is designed to measure the density of any fluid that enters this cavity. It does this using a float attached to two beams that are fitted with strain gauges. As the float rises in the liquid, the amount of up-thrust can be measured. The DEN also measures the viscosity of the liquid as it flows into or out of the cavity by monitoring the bobbing motion of the float and the rate at which this motion decays. Permittivity Sensor (PER) In the event of landing in a liquid, the PER will find out the electrical qualities of the fluid, and in particular its conductivity. The instrument is made up of 22 stacked parallel plates, the capacitance of which is measured at different frequencies. By briefly pulsing the sensor with direct current voltages the conductivity of the surrounding liquid can be determined. This instrument also has a thermometer in the form of a silicon diode. It's possible that during the descent to the surface, a build-up of residue or condensation may form on the instrument. If enough of this material collects on the PER, the sensing plates may be bridged and the conductivity of this material may also be measured Refractive Index Sensor (REF) The REF measures the refractivity of any liquid in the cavity of the probe. (Refraction is the change of direction of light when it enters a medium of a different density from that in which it previously travelled.) The instrument is made up of a cylindrical prism that is lit by two light emitting diodes (LEDs), one inside and one outside the prism. When immersed in liquid, light striking the interface between the liquid and the prism will be bent. The light will either escape or be reflected or refracted into the detector. The resulting transition from light to dark and the position of this transition is measured by a photodiode array that sits on one face of the prism. The refractive index of the liquid helps scientists to determine what the liquid is made of. This sensor isn't of much use before landing, and then only if it lands in liquid. However, during flight, condensation may form on this sensor, and its thickness and refractive index in this case can be sensed by the REF. Thermal Properties Sensor (THP) The THP measures the how heat conducts and the rate at which it diffuses in the probe's cavity. The sensor measures the initial temperature of the medium, as a starting point. It can measure the thermal properties of either gases or liquids and does this by using two different sets of hot wire sensors enclosed in cylindrical shields. By applying a known current for a fixed time through the sense wires in each of the four cylindrical canisters, the wires act as regulated heat sources. The heat generated is lost by conduction to the medium surrounding the wires at a rate that is determined by the thermal properties of the material. Measurements will be made every minute as the probe drops through the atmosphere and provides a very fine record of the thermal properties of the atmosphere. Tiltmeter (TIL) One of the most important analyses of the probe is how it moves, both as it descends through the atmosphere on the end of the parachute and after it lands. The tiltmeter provides information about the probe's attitude with respect to its local vertical position. During the probe's descent, it's sampled once a second. The tiltmeter will provide insights into the dynamics of the atmosphere along the descent path. It is also important in determining the probe's aerodynamic properties, which in turn can be used to reconstruct the probe's trajectory. Once the probe has stuck the surface, the TIL outputs are measured twice a second. If the probe is floating in a liquid the TIL will be capable of measuring any waves generated by all but the gentlest of breezes. Do the Mission Instructions Your probe has landed, but the onboard camera isn't working. Your mission: correctly identify the landing site from the map. The readings from the instruments will help you determine which of the six options is correct, but you will need to interpret the results. Once you have analysed the results, make your choice of landing site from the map and press "submit". Accelerometer External (ACC-E) Information Poking out from the bottom of the probe, this sensor is thrust into the surface as it lands, sensing the force of impact. If it lands in water it does not send back any useful information. Accelerometer External Reading Below are readings that represent typical soil types. Your task: click the soil type that most represents your graph to the left. Information Each graph represents the force of the probe plunging into the surface material. CORRECT! This is a sand reading. You can see by the smooth graph that the probe has little difficulty digging into the surface. The sharp fall in the graph after sample 250 represents the foredome of the Huygens probe hitting the surface and stopping any further downwards movement INCORRECT! Accelerometer External This is not a clay reading. Have another look at the graph and try again. CORRECT! Accelerometer External This accelerometer external graph represents a gravel reading. The differences between your graph and the sample below represents a fine gravel rather than a medium gravel. Accelerometer Internal (ACC-I) Information This device provides information about vertical accelerations experienced by the entire probe. It detects vertical movement on impact and also senses any vertical movement afterwards. Accelerometer Internal Reading (left) Your task: click the graph below that most closely resembles your graph. Information: The ACC-I measures the vertical movement of the probe on landing (how much it bounces). It will also measure any subsequent movement. CORRECT! Accelerometer Internal The low peak at the beginning of this graph indicates that the probe has had a soft landing, not much vertical movement on impact. The slight up and down movement could indicate that it is floating in liquid. CORRECT! Accelerometer Internal The low peak in the graph indicates that this is a soft landing. This could be sand or water, however there does not appear to be subsequent movement after the initial impact. INCORRECT! (If you have chosen a soft landing and your graph is a hard landing graph). Accelerometer Internal Have another look at the graph and try again CORRECT! Accelerometer Internal The high peak on the graph indicates that this is quite a hard landing. There does not appear to be any subsequent movement. Acoustic Properties Instrument - Sonar (API-S) Information This instrument measures the topography of the last few hundred metres of the probe's descent, using sonar. If it lands in liquid, it can also give readings of the depth of the liquid, effectively becoming a depth-sounder. Acoustic Properties Instrument - Sonar Reading (left) Your task: click the reading that most closely resembles your graph. The API-S uses sonar to measure the topography as the probe approaches the surface. If it lands in liquid, the probe then measures the liquid's depth. Please look closely at the map (which can be seen by clicking the "turn on map" button below) before you make your choice. CORRECT! Acoustic Properties Instrument – Sonar You have correctly estimated a descent into liquid. When selecting your final landing site, please look at the map closely to match the topography with your graph. Please pay particular attention to the "blip" you have in the middle of your reading, it will help identify something that the probe has flown over. INCORRECT! Acoustic Properties Instrument – Sonar Have another look at the graph and try again CORRECT! Acoustic Properties Instrument – Sonar You have correctly estimated a descent onto flat ground. When selecting your final landing site, please look at the map closely to match the topography with your graph. CORRECT! Acoustic Properties Instrument – Sonar You have correctly estimated a descent over a solid surface with lots of topography. When selecting your final landing site, please look at the map closely to match the topography with your graph. Acoustic Properties Instrument - Velocimeter (API-V) As the probe has landed, the Acoustics Properties Instrument - Velocimeter is now sitting on the surface, measuring the speed of sound in its surroundings. Your task: determine if the probe is measuring the speed of sound of air or seawater. Click the appropriate selection to add it to your mission data. Remember, Brighton is at sea-level. Hint: http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html Speed of Sound in Air http://www.es.flinders.edu.au/~mattom/Utilities/soundspeed.html Sound Speed Calculator (seawater) http://www.utdallas.edu/~pujana/oceans/sali.html Salinity- A conservative property of seawater Did you know? Sound will not travel through a vacuum, and travels at different speeds as it passes through different media. The speed of sound is about four times faster in water than it is in air. Acoustic Properties Instrument - Velocimeter (API-V) Designed to determine the make up of atmospheric gases, the API-V measures the speed of sound to do this, by sending out a signal and listening for the echo. If it lands in liquid, it measures the speed of sound in that liquid. Density Sensor (DEN) The Density Sensor only activates when it comes into contact with a liquid. It measures the density of any liquid it comes into contact with. This helps to confirm readings from other instruments that determine what the liquid is made up of. Your task: select this reading to add it to your data. Hint: http://hypertextbook.com/facts/2002/EdwardLaValley.shtml Density of Seawater http://www.es.flinders.edu.au/~mattom/Utilities/density.html Seawater Density Calculator Did you know? The density of liquids is one of the key factors that determines movement in liquids. Density differences caused by surface heating and cooling can result in very strong currents. Density Sensor (DEN) If the Huygens probe lands in fluid, this sensor measures the density of the fluid that it lands in. It does this by using a float attached to strain gauges. Permittivity Sensor (PER) Reading The Permittivity Sensor only comes into effect if it comes into contact with liquids. In the Huygens probe it measures the permittivity of a liquid. It uses an array of capacitors to do this. A typical measurement for fresh water is 80. Your task: select the button to add this reading to your data. Hint: http://fate.clu-in.org/table.htm Approximate Electromagnetic Properties of Various Materials Did you know? Permittivity is the quality of a material that allows it to store an electrical charge. Materials with high permittivity can store more charge than a material with lower permittivity. Permittivity Sensor (PER) In the event of landing in a liquid, the Permittivity Sensor measures the electrical qualities of the liquid. It also contains a thermometer. Refractive Index Sensor (REF) The Refractive Index Sensor measures the refractivity of any liquid that enters the "top hat" of the Huygens probe. Refractivity is the measurement of the change in angle of light as it changes mediums. Your task: select this value to add it to your data. Hint: http://micro.magnet.fsu.edu/primer/java/refraction/refractionangles/ Refraction of Light (needs Java) http://www.robinwood.com/Catalog/Technical/Gen3DTuts/Gen3DPages/RefractionIndexList.html Refraction Index of Various Substances for 3D modellers. Did you know? The refractive index in a vacuum is 1.0. Refractive Index Sensor (REF) Only activating in the case of a liquid landing, the REF sensor measures the refractive index of any liquid it lands in. Thermal Properties Sensor (THP) Reading The Thermal Properties Sensor measures how heat is dispersed in the probe's cavity. It does this in either liquids or gases. It also measures the temperature. Your task: decide from the reading if the probe has landed in seawater or air. Hint: http://en.wikipedia.org/wiki/Thermal_conductivity Wikipedia: Thermal Conductivity Did you know? That the measure of temperature in Kelvins starts at absolute zero, but has the same scale as Celsius? Zero degrees Celsius is 273.13 degrees Kelvin. Liquid reading: 0.570 W/m-1/K and 8 deg C Sand and Gravel: 8 deg C Thermal Properties Sensor (THP) Information This instrument measures how heat conducts and the rate at which it disperses in the probe's cavity. It can measure either gases or liquids, using a regulated heat source to do so. Tiltmeter (TIL) Information One of the most important instruments on the probe, the tiltmeter measures the swaying as the probe descends through the atmosphere. If it lands in liquid, the TIL measures any waves it encounters. Your Tiltmeter Reading (left) The tiltmeter measures swaying beneath the parachute in two directions(x and y) as it descends through the atmosphere. Once landed, it continues to measure the tilt of the environment it finds itself in. Your task: analyse your reading and match it to the closest landing reading below. CORRECT! Tiltmeter The first part of the graph represents the descent beneath the parachute. The subsequent signal after landing indicates that the surface continues to move. INCORRECT! Tiltmeter Have another look at the graph and try again. CORRECT! Tiltmeter The first part of the graph represents the descent beneath the parachute. The subsequent signal after landing indicates that the surface is tilted about 3 degrees on one axis and about -2 degrees on the other. CORRECT! Tiltmeter The first part of the graph represents the descent beneath the parachute. The subsequent signal after landing indicates that the surface is relatively flat. Sand Landing Results CONGRATULATIONS! You've accurately estimated that the landing place is sandy and hence has a soft surface. You've analysed the gases that make up Brighton's atmosphere, taken a look at the temperature and have had a look at the topography over which the probe has flown. You know that the probe is on a slightly sloping surface, and have correctly said that this is Brighton beach.


The scientists will be using these very same instruments to analyse the Titan environment. Imagine how much more difficult it will be given that there's so little we know about Saturn's moon.


By correctly analysing the data you have proven yourself to be a true scientist. If you're want to develop your interest, take a look at our selection of courses in the "Taking it further" section. This is one of three missions. If you would like to try another mission, click "New Mission" (below) Caption: The probe has landed on Brighton Beach. Why don't you try another mission. We have three! Credit: Open University Sand Landing Results - Final Mission. CONGRATULATIONS! You've accurately estimated that the landing place is sandy and hence has a soft surface. You've analysed the gases that make up Brighton's atmosphere, taken a look at the temperature and have had a look at the topography over which the probe has flown. You know that the probe is on a slightly sloping surface, and have correctly said that this is Brighton beach. You have now completed all three of the missions. Well done! Gravel Landing Results CONGRATULATIONS! You've accurately estimated that the landing place has fine gravel, a hard landing, a horizontal surface, and you've had a close look at the map to match it with the topography. Well done you have successfully completed this mission! Your landing site is on a gravel path in the gardens outside the Royal Pavillion in Brighton. The scientists will be using these very same instruments to analyse the Titan environment. Imagine how much more difficult it will be given that there's so little we know about Saturn's moon.


By correctly analysing the data you have proven yourself to be a true scientist. If you're want to develop your interest, take a look at our selection of courses in the "Taking it further" section. There are three missions. If you would like to try another mission, click New Mission (below). Caption: Credit: Open University There are three missions over Brighton. Click the "New Mission" button to launch another probe over Brigton. Gravel Landing Results – Final Mission. CONGRATULATIONS! You've accurately estimated that the landing place has fine gravel, a hard landing, a horizontal surface, and you've had a close look at the map to match it with the topography. Your landing site is on a gravel path in the gardens outside the Royal Pavillion in Brighton. Well done you have successfully completed all three of the missions! Caption: Credit: Open University

You have now completed all of the missions. Well done! Liquid Landing Results CONGRATULATIONS! You've accurately estimated that the landing place is in sea water for this mission. This has allowed a large number of instruments to activate so you now know many of the properties of sea water. You've had a look at the topography and the tilt of the probe, and you know that it flew over Brighton pier to land in the water nearby. The scientists will be using these very same instruments to analyse the Titan environment. Imagine how much more difficult it will be given that there's so little we know about Saturn's moon. By correctly analysing the data you have proven yourself to be a true scientist. If you want to develop your interest, take a look at our selection of courses in the "Taking it Further" section. This is one of three missions. If you would like to try another mission, click the "New Mission" (below). Caption: There are three missions over Brighton. Click the "New Mission" button to launch another probe over Brigton. Photo: Open University Liquid Landing Results – Final Mission CONGRATULATIONS! You've accurately estimated that the landing place has fine gravel, a hard landing, a horizontal surface, and you've had a close look at the map to match it with the topography. Your landing site is on a gravel path in the gardens outside the Royal Pavillion in Brighton. Well done you have successfully completed all three missions! Caption: You have now completed all of the missions. Well done! Photo: Open University INCORRECT. If you would like to re-examine your mission details and have another go, click the "Try Again" button. Try to match the data that you have from the instruments with the landing place on the map. Don't be afraid to use the hints where applicable, as these will help clarify what the instrument readings mean. There are a total of three missions. If you would like to try a brand new mission, click the "New Mission" button. Caption: The rollercoaster at the end of Brighton Pier. You might want to try again. Credit: Open University Recommended reading: Teach Yourself Planets (2nd edition 2003)by David Rothery (a cheap, readable and up-to-date survey of the entire Solar System) Hodder & Stoughton ISBN 0-340-86760-4 The New Solar System (4th edition 1999)J Kelly Beatty (Editor), Carolyn Collins Petersen (Editor), Andrew Chaikin (Editor) Cambridge University Press ISBN: 0521645875 To take your interest further, visit the websites of the http://www.britastro.org/main/ British Astronomical Association and the http://www.popastro.com/ Society for Popular Astronomy You could also try a course at the Open University. Look through the following pages to read about the courses available. Caption: Artist's impression of the Huygens probe descending through the atmosphere of Titan. Image: ESA Introductory Level Courses These short courses are presented 4 times a year and you can spread your study over 2 months or longer - the choice is yours http://www3.open.ac.uk/courses/bin/p12.dll?C02S194 S194 Introducing Astronomy - a wide-ranging introduction to astronomy including observations of the night sky. http://www3.open.ac.uk/courses/bin/p12.dll?C02S196 S196 Planets: an Introduction - an introduction to planets and minor bodies in our solar system, as well as planets around other stars http://www3.open.ac.uk/courses/bin/p12.dll?C02S197 S197 How the Universe Works - topics in cosmology and particle physics explore the origin and behaviour of the Universe. http://www3.open.ac.uk/courses/bin/p12.dll?C02S198 S198 Exploring Mars - focuses on the geology and environment of the red planet, and looks at whether life may now exist, or in the past have existed, on Mars Caption: Hugyens descends. Image: ESA-D DUCROS Standard Courses These longer courses are presented from February each year and last for 9 months. The courses are intended for a wide range of people, and with proper preparation, they are suitable for anyone who has a general interest in astronomy, and who want to develop their understanding of astronomy and planetary science - e.g. amateur astronomers, or schoolteachers who want to use the enormous attractiveness of the subject matter to enhance their teaching of science (at all levels). http://www3.open.ac.uk/courses/bin/p12.dll?C02S282 S282 Astronomy - covers the life cycles of the Sun and other stars; the Milky Way and other galaxies; and the evolution of the Universe. It includes project work and computer-based multimedia activities. Caption: Enhanced-colour image of Saturn's rings. Photo: NASA/JPL. Standard Courses http://www3.open.ac.uk/courses/bin/p12.dll?C02S283 S283 Planetary Science and the Search for Life - covers the origin and evolution of the solar system; planetary processes; and the structure and atmospheres of planets. It explores the search for extrasolar planets and the possibility of life existing beyond the Earth. http://www3.open.ac.uk/courses/bin/p12.dll?C02S250 S250 Science in Context - to be launched in 2006, this course includes a case study of Near Earth Objects and their past and future influence on the Earth as a result of impacts. http://www3.open.ac.uk/courses/bin/p12.dll?C02S269 S269 Earth and Life - if the relationship between meteorites and "native" Earth rocks has caught your imagination, you might find this course of interest; it explores the interplay between geology, climate and life on our planet Caption: The probe heads for a "splash-down" in this artist's impression. Illustration: Craig Attebery/NASA