KeplerdetectorAt 11:49 am on March 7, 2009 Beijing time（US Eastern Time10:49 p.m. on March 6), from FloridaCape Canaveral Air BaseLaunch pad 17-B, yesU.S.AThe first probe launched by NASAterrestrial planetDetectors for.Its scientific research mission is to detect more than 100000 stars in the Milky Way, hoping to find Earth like planets that can support the existence of life[1]。
According to American Space Network, if NASA's Kepler probe can successfully enter space orbit on March 7, Beijing timeterrestrial planetThis will open a new way for mankind to explore the universe.Kepler probe plans to explore more than 100000 stars in the Milky Way, hoping to find earth like planets that can support the existence of life.Jon Morse, director of the Astrophysics Department of NASA, said: "Kepler probe will give us a new understanding of the Milky Way, and its discovery in the future can change human's view of the Milky Way." According to the latest launch plan, the probe will be launched from 11:49 a.m. to 11:52 a.m. Beijing time on March 7（US Eastern TimeMarch 6, 10:49 p.m. to 10:52 p.m.)Cape Canaveral Air BaseThe 17-B launch pad was launched by the "Delta II" carrier rocket.It is reported that NASA delayed the launch by one day and increased the safety inspection of the launch vehicle. Last week, NASA's launch vehicle failed to deliver aSpace probeSent to space orbit.
The Kepler detector with an investment of 600 million dollars is based on Germany in the 17th centuryscienceIt was named after Johannes Kepler, who was one of the pioneers in the field of planetary research in the 17th century.Morse said: "400 years later, we use Kepler's research findings to try to uncover the most profound and basic problem of our Milky Way - how many Earth like planets are there in the Milky Way?"
The mission research team pointed out that the Kepler detector will use an unprecedented combination of light detectors (which can reach 9500 megapixels) to capture the subtle photometric changes of extrasolar planets orbiting stars.On earth, high-end digital camera can reach 10 megapixels, while Kepler detector can reach 95 megapixels[2]。
technical design
Announce
edit
Appearance structure
The top is the main mirror, which is covered with sunshade;
On the left isSolar panel, used to absorb solar energy and provide power for all instruments;
On the right side is the spectrometer, below which is the CCD detector and radiator;
The lower left side is the star tracker;
The lower right side isHigh gain antenna；At the bottom is the thruster module[3]；
Instrument composition
Space spectrometer: 0.95m aperture;
Main mirror: hollow structure with a diameter of 1.4m and 85%;
CCD detector: 95 million pixels (42 electronic couplers with 2200x1024 pixels);
Bandpass: peak half width 430-890 nm;
Dynamic detection range: 9-16 magnitude stars;
High quality guidance sensors: 4 electronic couplers (CCDs) positioned on the scientific focus plane[3]；
system performance
Scientific data storage time: more than 60 days;
Uplink X-band: 7.8125 bps － 2kbps;
Downlink X-band: 10 bps - 16 kbps;
Downlink Ka band: the maximum value is 4.33125 Mbps;
Except for disposable devices, all mechanical device surfaces are covered, and the main mirror has three focusing devices;
Mass of flight components and assembled instruments: 1071 kg (estimated maximum);
Power of flight components and assembled instruments: 771W (estimated maximum)[3]。
Detection technology
Announce
edit
According to foreign media reports, NASA's Kepler probe is the first to search the Milky Wayterrestrial planetThe main method of searching for Earth like planets is to observe the phenomenon of "planetary transit" through relevant advanced instruments, and then judge and obtain the details of the planet and its star system.
From an observer's point of view, when a planet is in front of a star, this phenomenon is called "transit".The transits of terrestrial planets will rarely change the bright spots of stars, only about 1/10000 of which will last for 2-16 hours.If the transit phenomenon is completely caused by the natural movement of the planet, then this movement change will be completely cyclical.In addition, all transits of the same planet should have the same bright spot changes and last for the same time.Therefore, the "planetary transit" detection method has a strong repeatability signal and a sound detection method.
Once a planet is detected, the orbital size of the planet will be calculated by the operating period, andKepler's third lawThe mass of the star can be calculated according to the planetary motion law in.The volume size of the planet can be calculated by the brightness of the planet and the volume of the star in transit. Based on the size of the planet's orbit and the temperature of the star, the temperature characteristics of the planet can be calculated from.Through the above series of calculation and observation data, it can be inferred whether the planets currently observed are suitable for life[4]。
Observation of "Planetary Transit" with Advanced Instruments
Related reports
Announce
edit
Send back the first batch of pictures
On April 20, 2009, according to the website of NASA, NASA's Kepler probe has sent back the first batch of star images to the Earth,scienceWe hope to find Earth like planets through the survey results of the spacecraft.
The image contains at least 4.5 million stars
This group of first pictures focused on a large number of stars in the Cygnus constellation and Lyra constellation of the Milky Way. Lia LaPiana, director of the "Kepler" project at NASA headquarters in Washington, said, "Kepler's first observation results are amazing! It's very exciting to see millions of stars in one picture!"
In the first group of photos taken, there is a star cluster called "NGC 6791" 13000 light-years away from the Earth, and a star called Tres-2 is photographed in another picture. The star has a Jupiter like planet that rotates around it every 2.5 days[5]。
Fig. 1 The panorama of stars in the first group of pictures taken by NASA's Kepler probe. The NGC 6791 star cluster is magnified in the upper left corner of the picture. It is 13000 light years away from the Earth, and the star cluster has a history of 8 billion years.In the upper right corner of the image, a star called Tres-2 is magnified. The star may have a planet similar to Jupiter.It is estimated that the photo contains 4.5 million stars, of which about 100000 planets will be investigated as candidates for Earth like planets.
Fig. 1 Star panorama
Discover the new solar system
On August 26, 2010, according to the US Space Network, the Kepler probe recently found that there was a planetary system similar to the solar system only 127 light-years away from the Earth. At least five planets in the planetary system were orbiting the stars. The arrangement of the planets was very similar to the solar system. At the same time, there might be two undetected planets.This latest discoveryPlanetary systemIt will become the system with the most planets found in the planetary system so far. Previously, astronomers detected that 55 Cancri planetary system has five planets inside, two of which are gas giant planets, while HD 10180 planetary system has no gas planets.Lovis said: "Planetary systems with low mass planets are common, but their formation history is still a mystery[6]。”
Faulty
On April 12, 2016, according to foreign media reports, the expensive NASA Kepler exoplanet probe recently encountered a problem. The probe is currently in emergency mode, about 75 million miles from the Earth.The ground controller found the problem on Thursday, and the last contact time was April 4. It seems that everything is normal. Currently, NASA is investigating what happened to the probe.So far, Kepler extragalactic planet detector has found nearly 5000 extragalactic planets, and observed millions of stars in the Milky Way to find those extragalactic planets similar to the Earth[7]。
