synonymTranssolar extraplanetary survey satellite(NASA's exoplanet search project) generally refers to the extragalactic planetary survey satellite
Transiting Exoplanet Survey Satellite (TESS) isNASAThe latest exoplanet search project.Scientists hope that TESS can observe at least 200000 stars during the two-year space flight mission, and eventually discover thousands of new exoplanets.
NASA is scheduled to launch the "Transsolar Extraplanetary Survey Satellite" on the evening of April 16, 2018 local time to search forExtrasolar planets, hoping to discover the "other earth" that may gestate life.[1]
At 6:51 on April 19, 2018 (Beijing time), TESS took SpaceX'sFalcon 9The rocket was successfully launched.It is not only the right-hand man of the James Weber Telescope, which was launched around 2020, but also the previous launch of NASAKepler space telescope The successor of.[2]
TESS is the predecessor of the High Energy Transient Explorer 2 (HETE-2), a small satellite designed and built by Massachusetts Institute of Technology and launched by NASA on October 9, 2000. The satellite has been operating in space for seven years, and its mission is to discover and locate high energyGamma rayAnd X-ray bursts.
In order to detectGamma ray burstThe MIT team led by George Ricker, the chief scientist, designed a CCD camera that can observe visible light and X-rays to record the strength and position of the signal.Team member Joel Villasenor said that the invention of CCD was a leap in the history of astronomical observation, which made signal processing very simple.
In 2004, Ricker and the HETE-2 team suddenly wondered whether HETE-2 could be used to observeExoplanet？At that time, humans only found less than 200 exoplanets, of which only a few were discovered by the transit method.According to the latest data, the total number of planets discovered by humans has reached 3700. With the help of more powerful space telescopes, this number may rise to tens of thousands within ten years.
Villasenor said that practice has proved that the transit detection attempt of HETE-2 did not fully achieve the expected results.However, this attempt has laid the foundation for the subsequent CCD imaging exoplanet exploration mission.[2]
Pade Boyd, head of the GIP office of NASA Goddard Space Flight Center, said, "The goal of GIP is to let TESS generate as much scientific data as possible. TESS can be used for shining young stars, star pairs, supernovae in neighboring galaxies, and even supernovae in distant active galaxiesSupermassive black holeObserve.TESS will greatly broaden our horizon of the universe. "[3]
Project team
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Project support: NASA astrophysical exploration
Project leader: MIT in Cambridge, Massachusetts
Project management: NASA Goddard Space Flight Center in Greenbelt, Maryland
Other institutions participating in the project: Orbital ATK, NASA Ames Research Center, Harvard Smithsonian Center for Astrophysics, Space Telescope Science Institute, and many other universities, research institutions and observatories around the world.[2]
R&D process
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In 2006, the MIT team led by Ricker proposed a new low-cost small satellite program HETE-S to NASA's exploration mission project.The team originally planned to raise $20 million by itself, but in view of the high cost and the growing popularity of the discovery of extraterrestrial planets, the team decided to seek funding from NASA and apply for $120 million in project funding.In 2008, the team formally submitted an application to NASA's small exploration mission project, and TESS project officially started.
Initially, TESS included six CCD cameras, which were expected to operate in low Earth orbit, similar to the HETE-2 mission.This orbit design is helpful to improve the observation efficiency with the help of the data receiving ground station of the HETE-2 mission.
However, the team found that the strong geomagnetic field in low Earth orbit will lead to significant jitter of the satellite, which will cause unacceptable interference to TESS's highly sensitive camera.
Therefore, NASA rejected the first project application.With the help of Orbital ATK and NASA Goddard Space Flight Center, the research team began to redesign an orbit called "lunar resonance".This kind of orbit can provide the whole sky observation field of vision on the premise of ensuring the stability of the aircraft, which can be regarded as an innovation.[2]
Satellite parameters
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"Tess" is 1.5m high, and the solar wing, namelySolar panelIt is about 1.3 meters in diameter and weighs 363 kilograms when it is folded up, which is smaller than most space exploration satellites.According to NASA, its size is between a refrigerator and a "washing and drying machine".[1]
Detection principle
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When an exoplanet passes in front of the central star, it will temporarily block some light, causing the starlight to darken. TESS telescope can judge the volume of the planet and the time of circling the star based on this. These two pieces of information are crucial to understand whether a planet supports life.
Tess uses the transit method to detect exoplanets. The principle is that when a planet passes in front of the star, the star can be observed to "darken"."Tess" will replace the "predecessor" who is about to run out of fuel -- launched by NASA in 2009Kepler space telescope The latter has so far discovered 2300 confirmed "candidate" planets.
Tess is equipped with four advancedwide-angle lensThe observed space area is 350 times larger than Kepler, and the observed stars are on average 30 to 100 times brighter than Kepler.[1]
Launch process
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TESS launch
NASA is scheduled to launch a probe satellite on the evening of April 17, 2018 Beijing time to search forExtrasolar planets, hoping to discover the "other earth" that may gestate life.
This satellite is called "Transsolar Extraplanetary Survey Satellite", which is abbreviated as "Tess" (TESS). It is scheduled to be carried by the US Space Exploration Technology Corporation's Falcon 9 rocket at 6:32 on April 17, Beijing time, from FloridaCape Canaveral Air BaseLaunch.[1]
NASAAnd SpaceX postponed the launch of the Transsolar extraplanetary survey satellite to 6:51 a.m. Beijing time on April 19 and successfully launched it.[4]
Target Task
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Project objectives
TESS needs to search for exoplanets around the solar system hundreds of light years or even closer to the Earth.
Joshua Pepper, co director of TESS's target selection working group, said that among the stars that TESS will observe, small and bright white dwarfs are ideal for determining planets.One of the goals of TESS is to find thatSuper EarthThe size of the planet.
Although searching for transiting exoplanets is the main goal of this mission, TESS will patrol almost the whole sky, so it will also observe other celestial bodies through the Guest Investigator Program (GIP).
Scientific tasks
TESS will divide the sky into 26 different regions and search almost the whole sky.The powerful camera on the detector continuously checks each area, and patrols every 27 days;The visible light from the brightest object is measured every two minutes.TESS will check the apparent magnitude (referring to the brightness of stars seen by the naked eye. The higher the apparent magnitude, the darker the star), some of which are even visible to the naked eye.
Tess's main mission is to "scan" more than 200000 stars outside the solar system that are "the nearest and brightest" to the Earth in the next two years to confirm whether there are planets orbiting them.NASA predicts that it will find 20000 exoplanets, of which more than 50 are "about the same size as the Earth", and at most 500 are "twice the size of the Earth".[1]
scientific discovery
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In July 2019, the "Transsolar extraplanetary exploration satellite" found three satellites 73 light-years awayExtrasolar planets, between Earth and Neptune in size.There are no such planets in the solar system. Researchers believe that the new research has filled in the "missing link" in the process of planet formation.The three newly discovered planets revolve around the same star near the sun. The researchers named this star system "TOI-270".amongRocky planetTOI-270b is 25% larger than the Earth, close to the parent star, and has high surface temperature;TOI-270c and TOI-270d are mainly composed of gas, and their volumes are 2.4 times and 2.1 times of the Earth's respectively.[5]
In June 2022, the "Tess" mission found two "new worlds" that may contain rocks and minerals. They revolve around our cosmic neighbor star, the red dwarf HD 260655, which is only 33 light-years away from the Earth. It is one of the closest multi planet systems discovered so far.With this discovery, scientists can understand the composition of exoplanets and evaluate their atmospheres, providing important clues for people to search for extraterrestrial life.
These two newly discovered exoplanets are called "super Earth" - larger than Earth, but smaller than ice giant stars.They orbit an icy red dwarf called HD 260655.HD 260655 b is 1.2 times the size of the Earth and twice the mass of the Earth. It orbits the star once every 2.8 days.The planet HD 260655 c is 1.5 times the size and 3 times the mass of the Earth, and orbits the star every 5.7 days.According to the size, mass and density data, they are likely to be rocky planets, the researchers said.
The temperature of both planets is difficult to maintain the existence of life.The temperature of planet B is about 435 ℃, and that of planet C is about 284 ℃.The actual temperature depends on the possible atmosphere and its properties.[6]
In January 2023, an international team of astronomers detected a new "hot Jupiter" exoplanet, whose mass may be about three times that of Jupiter, orbiting a star named TOI-778, using NASA's "Transsolar Planetary Exploration Satellite" (TESS).Relevant research papers are published on the paper preprint website.[7]
On May 24, 2024, according to the information of IT House, astronomers observed Gliese-12b planet with the transiting extrasolar planet survey satellite (TESS), whose volume is between the Earth and Venus, 40 light-years away from the Earth. Based on relevant data, it is speculated that it may be an extrasolar planet similar to the Earth.[8]
