From the earth, for Saturn: Cassini 20 years course is coming to an end

//p.ivideo.sina.com.cn/video/251/636/740/251636740_400_300.jpg’,// video program thumbUrl: ‘http://p.ivideo.sina.com.cn/video/251 /636/740/251636740_400_300.jpg’,//html5 player on the video has not yet started to show the picture can be the same title with the pic title: ’20 years Cassini probe mission will welcome the curtain of the trip’, // title source : ”, // video release source. Such as: Xinhua Network. url: ‘http://video.sina.com.cn/view/251636740.html’}]}; $ widgetadd ({id: ‘pl_video_2’, loadTime: ‘DOMContentLoaded’, // initialize: true, require: ‘plsplayList.init (node, widget)}}; <plsplayList.init () Most people have never realized that there will be an important event today…. Although many people may never look at the sky to see one, but at 19:54 tonight, please look up at the southwest of the sky, if the weather can, you should see a shining white shiny Bright star. In the moment you looked up at it, there was a ship that departed from the earth 20 years ago on the planet. You should understand that at this moment, the world is countless pairs of eyes are the same with you, watching the planet, the memory of the dead space veterans. NASA will be broadcast live video, and Sina Technology will also follow the whole process for the reader to follow up. Cincinnati-Huygens Detector is a "Cassini-Huygens" detector, which is a "Cassini-Huygens" detector.

An international collaborative exploration program, led by NASA, the European Space Agency (ESA) and the Italian Space Agency, is attended by more than 20 countries around the world. It is also the first human probe to run around Saturn.

The project is based on two 17th century scientists: Jean Dominique Cassini of Italy and Christiaan Huygens of the Netherlands, both of whom have made an important interest in Saturn’s research contribution. Cassini found four Saturn satellites and found the ring between the Saturn aura (Cassini Gap); Huygens discovered the Titan in 1655, which is why landed Titan The detector was named “Huygens” for the reason. From the beginning, the Cassini Detector program was conceived as an international collaborative project. In 1982, the project was first proposed, shortly before that, two NASA “travelers” spacecraft just flew near Saturn. The detection data from two travelers’ detectors revealed a vibrant Saturn system, especially Saturn’s largest satellite, Titan, which sparked a strong interest in planetary scientists. They are eager to launch a special Saturn probe to do more in-depth investigation. In 1997, the “Cassini” spacecraft successfully launched, 7 years after the flight in space, in 2004, the ship finally arrived in Saturn and successfully entered the orbit. Along with the ship, there is also a Huygens lander made in Europe, which will be the first to land on Titan’s surface.

The implementation of the Cassini Detector mission almost revolutionizes our understanding of Saturn, including its complex aura, a variety of satellite and magnetic field environments. Cassini spacecraft is the most distant planetary satellite ever launched by humans. In the first time it arrived at Saturn began to return to the importantDetecting data and continuing to work so far, it is older than a lot of readers who are reading this article. Cassini spacecraft on the orange atmosphere enveloped, the surface has rich organic matter Titan conducted a focus on detection, boldly through the Titanic over the jet of water vapor “fountain”, and Saturn itself and the halo system has never been Detailed investigation. These data have fundamentally changed our understanding of the Saturn system and planetary formation theory.

Since the detector was much better than expected, the original Cassini probe, which had been planned for only four years, had been working for Saturn for 13 years until today, September 15, and it was about to end Glorious mission.

From the starting point to the end: Cassini – Huygens project timeline

October 15, 1997: A “Hercules IVB / Sagittarius “rocket will Cassini spacecraft from the United States Florida Canaveral Cape space launch launch;

April 25, 1998: Cassini – Huygens detector The first time close to fly the Venus, the implementation of the planetary orbital lever, the recent distance from Venus surface only about 284 km, the planet by leveraging the speed of Cassini spacecraft increased 7 km / s;

June 24, 1999: Cassini-Huygens Detector The second closest to the fly-off Venus, the implementation of the planetary orbit, recently from the Venus surface about 600 km; August 1999 17: After about two years after the launch, the Cassini-Huygens probe returned to Earth and carried out a third planetary orbit to fly. It was about 1,100 kilometers from the earth and flew over the South Pacific, and the earth gave the Cassini space to accelerate about 5.5 kilometers per second.

December 1999 ~ 2000 April: The Cassini-Huygens probe traverses the asteroid belt, which is the seventh ship in human history through the asteroid belt.

December 29, 2000: Cassini – Huygens detectors flew around Jupiter, about 10 million kilometers away. At that time, another spacecraft “Galileo” was working on Jupiter’s orbit, and two spacecrafts jointly investigated Jupiter;

July 1, 2004: Cassini-Huygens probe successfully cut into Saturn Orbital, becoming the first man-made Saturn satellite in human history and the most distant man-made planet in history;

December 25, 2004: Cassini mother ship releases Huygens Lander, which will flying alone 22 days, go to Titan;

January 13, 2005: Huygens lander successfully landed on Titan, so as to achieve the most distant human history once landing operations;

April 26, 2017: “magnificent final chapter” issued instructions issued, Cassini spacecraft in accordance with the instructions to adjust the track, set foot on the road against the destruction of Saturn;

September 13, 2017, Beijing Time is 19:54, the Cassini spacecraft will eventually burn in the atmosphere of Saturn, the end of the mission;

2, the Cassini Detector with the Huygens Lander

<123 The Cassini-Huygens probe is one of the most ambitious detectors ever launched by humans. She is equipped with the world's most advanced and most complex equipment and cameras, to obtain high-precision data and shooting high-definition images.

As the name clearly suggests, the Cassini-Huygens probe consists of two parts: the Cassini orbiter, and the Huygens Lander. The former flew around Saturn’s orbit and became the first Titan satellite, which in 2005 successfully landed on the surface of Titan, the only one in the solar system with a dense atmosphere of satellites, which also made the history of mankind One of the most remote landing operations. The Cassini-Huygens probe is designed with three-axis stability, with many different scientific loads, of which 12 devices are installed on the Cassini orbiter, and the Huygens Lander is equipped with 6 sets of equipment. The spacecraft maintains communication with the earth through a high-gain antenna and two low-gain antennas.

It can be said from a certain point that the Cassini spacecraft is a nuclear powered spacecraft because its power system is three “isotope thermal motor” (RTG), the principle is through 33 kilograms of radioactive isotopes Plutonium-238 (Plutonium dioxide) The heat generated during the natural decay process provides power for the spacecraft to ensure that the scientific equipment, control of computers and antennas and other normal work and temperature control.

In addition, it can be said that in some ways, Cassini detectors are more sensitive than our humans. For example, its “eyes” can perceive the light and energy that our naked eye can not perceive, and it also senses the changes in Saturn’s magnetic field and analyzes the density and composition of dust in the surrounding space that is extremely subtle and invisible to the naked eye.

The main scientific payload includes: <12(CAPS)

CAPS is a direct contact analysis (CAPS)

CAPS is a direct contact analysis (CDA)

CDA is the number of electrons and protons in the spacecraft (ie, the number of electrons and protons in the particle);

2) cosmic dust analyzer (CDA)

(<CIRS)

CIRS is a remote sensing device capable of measuring the size of the dust particles around the Saturn,

4) Ion and Neutral Particle Mass Spectrometer (INMS) INMS is a direct contact analysis of the <RTIgt; Equipment, the main purpose is to analyze Saturn and Titan in the space near the charged particles (such as protons and heavy ions), and neutral particles (such as atoms);

<1 (ISS)

ISS is a set of remote sensing equipment, mainly the various types of cameras, there are narrow angle cameras also have wide angle camera. (212) 6) Dual mode magnetometer (MAG)

MAG is a direct detection device that can be used in the field of visible light, but can also shoot infrared and ultraviolet band images; (MIMI)

MIMI is able to measure and sense the data and information associated with the particles bound by Saturn’s magnetic field.

Cassini equipped with a radar device, the device can be passive to receive radar wave reflection signal, you can also take the initiative to launch radar waves to detect (123)

9) Radio and Plasma Wave Scientific Equipment (RPWS)

RPWS is able to measure the radio signals emitted by Saturn, which is used to measure the radio signals emitted by Saturn. , Including signals generated by the interaction between the solar wind and Saturn and the Titan magnetic field;

10 ) RSS is a set of telemetry systems that use the signals from the earth to measure the earth’s atmosphere, such as by observing the radio signals coming from Earth on Saturn and Titan (UVIS)

UVIS is a remote sensing device that captures the surface of the object. The UVIS is a remote sensing device that captures the surface of the object. (VIMS)

VIMS is a remote sensing device that includes a remote sensing device, including a remote sensing device, including a remote sensing device, including a remote sensing device, including a remote sensing device, including a remote sensing device Two cameras: one working in the visible band and the other in the infrared band. Which can be used to determine the composition and structure of Saturn’s satellites, Saturn satellites, and Saturn and Titan’s atmosphere.

(HASI)

The device is mainly used for the Huygens Lander to determine the physical and electrical properties of the Titan atmosphere in the Lower Tate’s atmosphere. Electrical structure;

2) Doppler wind speed test (DWE)

The device uses a super-stable oscillator to help Huygens Lander to improve the flight with the track on the track Communication between the mother ship. While it can measure the wind speed in the atmosphere of Titan by the Doppler effect.

3) Falling Imaging / Spectrum Radiometer (DISR)

is mainly used to shoot the image of the Saturn’s surface below the descent process and measure the radiation balance between the Titan atmosphere and the surface (GC / MS)

This is a multi-purpose gas analysis device for identifying and determining the composition of the atmosphere.

5) Aerosol collector and pyrolysis analyzer (ACP)

This device collects aerosols in the air through a filter port when the spacecraft descends and puts it in a heater Evaporation and analysis to determine the organic composition; <1(SSP)

Because it was not possible to confirm whether the Huygens Lander landed was land or ocean in advance, the equipment package carried by it was prepared by both hands. Under what circumstances, it can work and collect the surrounding environment data;

3, Cassini’s magnificent chapter

After 20 years in space flight, NASA’s Cassini detectors are gradually approaching the end of its life. The main reason behind this is that the Cassini’s own fuel is about to run out, but the knowledge we have before tells us that several satellites around Saturn, such as Titan and Titan, may have suitable microbes Survival of the original livable environment, although the Cassini spacecraft before the departure of the disinfection, but if you do not know how, there are some small microbes even lucky to escape the disinfection of the kill, and even miraculously attached In the Cassini spacecraft and survived in space for 20 years, then in the future when the Cassini spacecraft fuel completely depleted, the Earth’s control personnel can no longer track and attitude of their proper control, out of control Of the spacecraft is likely to collide with Titan or Titan and other satellites, which may cause chemical and biological pollution, which for the future we carry out celestial biology research is unacceptable results. As a result, the scientists, after careful consideration, decided to allow the Cassini detectors to take the initiative to choose “suicide” when they had the last fuel and control the orbit, and burned safely in Saturn’s atmosphere. Since the beginning of 2010, the Cassini Detector began a seven-year mission extension, during which the spacecraft flew over several Saturn satellites and for the first time had a chance to make seasonal changes to Saturn monitor. The plan enrolled from the outset that all the remaining fuel of the Cassini spacecraft would be depleted during the seven-year mission and eventually ended in a way that was burned into the Saturn’s atmosphere. The fate of the Cassini spacecraft was finally destined in April 2017, when the Cassini spacecraft adjusted the track, and the new track would allow her to eventually burst into the Saturn’s atmosphere. But before that, she had five months. NASA scientists have planned a bold task for her: 22 times from Saturn and its halo between the narrow gap (width of not more than 2000 km) through, and the plan named “magnificent end chapter” (The Grand Finale). This is an unprecedented unknown area, and the work of the Cassini spacecraft during the last five months of life will greatly enrich the scientists’ understanding of the region. On September 15, 2017, the Cassini spacecraft will be the closest to Saturn. But this is similar to the previous hundreds of similar is not the same, this time she will not bypass Saturn, but bravely hit the gas planet, into the Saturn’s atmosphere, and in the process of using only The last remaining fuel start-up gestures control the engine to maintain its posture, align its antenna at Earth, and turn on all the detection equipment, and send all the data that can be collected to the earth in the process of falling incense until she can no longer Support until finally crushed. Earth’s control center, that from Saturn, lasted for 20 years of cordial signal will eventually disappear.

4, Cassini’s scientific achievements

Before the Cassini spacecraft, we had little knowledge of Saturn. Pioneer 11 and two traveler spacecraft in a few decades ago on the Saturn has a brief fly swept inspection, in a hurry to take some images, and get some close detection data.

These pioneering probes show us a complex planetary world, a brilliant aura, a variety of satellites and a strange magnetic field. But all of these are fragments of time, and scientists need continuous observation data.

So, the special Saturn detectors: Cassini detectors came into being. This is the first time mankind has the opportunity to observe Saturn and its satellite system at close range. Saturn’s year is about twenty years on earth, that is, the length of every season on Saturn is equivalent to a full seven years on earth. From 2004 to 2017, Cassini spacecraft in Saturn orbit running a total of 294 laps, continuous observation for up to 13 years, almost equivalent to six months on Saturn’s time. At the time of the arrival of the Cassini spacecraft, Saturn’s northern hemisphere is gradually coming out of the deep winter, usher in the new spring. And now, Saturn’s northern hemisphere has begun to meet the arrival of the summer. Cassini spacecraft and too much scientific achievements, in a limited space there is no way to narrate, the following only one of the most important Titan six and Titan found the introduction:

Between the Cassini detectors, we know very little about Titan, only know It is Saturn’s largest satellite, almost close to the size of Mercury, and is covered by a thick layer of nitrogen-rich atmosphere. And the Cassini Detector carrying the device to penetrate this thick layer of the atmosphere, let us glimpse the Titan’s surface, analyze its atmospheric composition, and found Titan six surface of the liquid ocean, and even the first time Put a lander on Titan!

2005 after landing operations around the worldScientists have been busy analyzing the data returned by the Huygens Lander. These data greatly enriched our understanding of this mysterious world. We now know that there are lakes and oceans on Titan, whose lakes are mainly methane and ethane, and these lakes are more concentrated in the polar high latitudes and at low latitudes Equatorial areas are widely distributed in arid areas, a large number of dark black, composed of hydrocarbons composed of desert cover these areas. While in Titan’s deep underground, there may be a huge liquid ocean of water.

The long life of the Cassini Detector gives Scientists the opportunity to monitor the Saturn system for the first time because some things have to be sustained for a certain period of time to achieve results, such as water cycles and Four seasons change. Titan is the only planet in the whole solar system that is found to have a liquid circulation in addition to the earth, although its liquid is not liquid water. Titan on the length of each season is 7.5 Earth years. Since 2011, the Cassini detectors have noticed a trend from winter to winter in the Antarctic region of Titan, while the northern hemisphere began to show signs of summer. On the surface of Titanic, the Cassini spacecraft observed a large number of wavy dunes on the Sahara Desert, similar to the Earth, mainly in the area near the equator. Scientists believe that these dune components are not silicate but organic compounds composed of hydrocarbons. The image shows that the width of these dunes can generally reach 1 to 2 km, stretching hundreds of kilometers, the height of more than 100 meters, very large.

Huygens Lander for the first time to achieve the bottom of the atmosphere of Titan direct detection. The data returned includes the height data of the various gaseous components, the isotope ratio and trace gases, and the organic particulate content. The Huygens Lander also conducted a direct sampling and analysis of aerosols and confirmed that the main components of these particles were carbon and nitrogen. Scientists have noted that the Titan atmosphere shows complex chemical properties, mainly by the interaction of methane and nitrogen and the formation of complex chemical molecules, and ultimately the formation of the entire Titan six thick orange haze The Scientists believe that there will be rainfall on Titan, but the drop is not liquid water droplets, but the liquid methane and ethane, but Titan on why there are so many organic substances, is still unable to explain.

2) of Enceladus – frozen water planet

For decades, scientists do not know Enceladus is actually the highest solar system inside surface albedo Planet – that is, the planet looks the most white! We do not know how there is a close relationship between Titan and the E ring in Saturn’s aura. Cassini’s test results found that the Titan covered the surface of the “snow”, as well as E ring in a large number of ice particles, in fact, from the Titan under the global brine ocean and the surface of the formation of space hot spring jet The Before the arrival of the Cassini spacecraft, the planetary scientists only noticed in the images taken by the travelers in the 1980s that the terrestrial surface seemed particularly smooth and had a high brightness. But then we learned that, in fact, this 500 km diameter small satellite is the solar system in the highest albed the planet.

The data collected by the Cassini spacecraft’s magnetometer caused the attention of the scientists – there was something in the vicinity of Titan II that disturbed the Saturn’s magnetic field, and there seemed to be something out of the earth injection.

Soon, the Cassini spacecraft will find out the truth: Titan is a very active planet, its underground there is a huge global underground saltwater sea. And through its giant rift system on the ground, the underground ocean is jetting large amounts of water vapor and ice crystals in space, and the Cassini spacecraft is measuring about 400 meters per second, forming a terrestrial scale Hundreds of kilometers of “space fountain”. Some of the water and ice material will fall back to the Titan table, which formed the “snow”, while others fled the Titan and added to the ring in the ring of Saturn E ring.

In 2005, the camera on the Cassini spacecraft performed a detailed imaging of the Earthwatch, and found a large number of rift systems known as the “tabernacle” in its Antarctic region. The terrain here is unexpectedly young and complex, almost completely without crushing the pit. The whole area seems to float a lot of sea icebergs and cracks throughout the surface. Surprisingly, the detectors also detected the presence of water vapor and ice crystals at the top of these rift systems. Subsequent data analysis did confirm that the rifting is being ejected. In a close flight in 2008, the Cassini spacecraft bravely passed through the water mist directly and analyzed the water vapor samples directly using the equipment. It was found that the components included volatile gases, water vapor , Carbon dioxide and carbon monoxide, and organic substances. And the density of these organic substances is more than 20 times the expected value in advance. With the passage of time, scientists have noticed that these rift systems of the Titanic are in constant movement, and in some places the rift is shrinking, and in some places it is expanding. It is clear that Titan is suffering from a strong tidal effect, and this is likely to provide a small amount of heat for this little planet.

by gravity measurement data, SectionThe scientists believe that there is a giant underground ocean of about 10 kilometers deep under the Tugo II Antarctic area below about 30 to 40 kilometers of ice.

In October 2015, the Cassini spacecraft flew the last time, but the data she collected will allow scientists to benefit from the next few years.

Postscript:

The Cassini spacecraft is a robot, it is not conscious, no feelings, will only faithfully perform the works of the earth Each of her instructions, in the past 20 years, these instructions to Cassini spacecraft go west, and at the same time to avoid the Saturn and the surrounding satellite and halo collision. 20 years, Cassini spacecraft under the guidance of the ground command, made a fruitful results and good health, intact.

At some point on April 26, 2017, as usual, the Cassini spacecraft receives an instruction issued on Earth: adjust the orbit. Cassini spacecraft, as always, faithfully executed this directive, but this directive is not the same as before, this new track will let her eventually embarked on the Saturn’s atmosphere and completely burned the no return.

At this moment, 1.5 billion kilometers away from the depths of space, Cassini spacecraft is heading for Saturn’s atmosphere without hesitation to fly, it will try to antenna at Earth, issued a final batch of data, Until it turned into a meteor across Saturn’s sky. This is the earth’s most special gift to Saturn.

Tribute, 20 years of space heroes. Goodbye, Cassini. (Morning wind)

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