The National Aeronautics and Space Administration (NASA) is exploring Uranus as part of its mission to reach distant planets such as Uranus and Neptune, even in what is called “deep space.”Orbital probe of UranusI’m thinking of a mission. on the other side,In China, a mission is planned to send a probe to Neptune’s moon “Triton”.
A research group from the China National Astronomical Administration (CNSA), the Chinese Academy of Sciences (CAS), the China National Atomic Energy Agency (CAEA), and the China Space Technology Research Institute (CAST) has published plans to explore Triton in the journal Scientia Sinica Technologies. . According to the same paper,Nuclear power will be used as a power source for spacecraftIt is said that
“Ice giants” such as Uranus and Neptune may contain important scientific discoveriesIn particular, Triton, Neptune’s largest moon, is originally outside Neptune because it is a retrograde moon that rotates in the opposite direction to Neptune’s rotation, and because its composition is similar to that of Pluto.Edgeworth Kuiper beltIt is a dwarf planet that formed in and is expected to have been pulled from the Kuiper belt by Neptune’s gravity.
Against this background,Studying Neptune’s orbital dynamics can provide answers to how the solar system formed and evolved, giving rise to life.it’s called.
Background of the use of nuclear energy
The research group assumes that the power source for the spacecraft that will be sent to Triton isNuclear Energyhe is. According to the research group, assuming a spacecraft mass of 3,000 kg or less and a spacecraft life of 15 years or more, 8 kW for electric propulsion, 2 kW for payload,A total power supply of 10 kW or more is requiredIt is said that however,The amount of solar energyInversely proportional to the square of the distance, so the intensity of light near Jupiter isabout 4%There is only one. Therefore, only nuclear energy is said to enable exploration in deep space far from the sun.
So far, NASA’s Mars rover Curiosity and Perseverance and the interplanetary probe Voyager have used nuclear batteries as energy sources.The research group uses electricity converted from nuclear energy in the spacecraft’s electric propulsion systemHe says he is considering doing it. But in the case of “plutonium-238” expected as an energy source, it is difficult and expensive to manufacture, so it seems difficult to prepare enough plutonium to meet the energy demand of 10 kilowatts or more.
Therefore, the search group uses“Uranium 235”I’m thinking that although a system using uranium-235 has a large mass, it is less efficient in power supply, but it is said that it can provide more energy for electric propulsion, which has higher specific pulses (higher efficiency) than chemical propulsion. It is planned that the spacecraft will be equipped with four electric thrusters with a thrust of 160 million Newtons, two of which will be used simultaneously (the remaining two will be used as spare). For reference, the Japanese asteroid explorer “Hayabusa 2” is equipped with four ion thrusters with a thrust of 10 millinewton, and up to three can be used simultaneously.
At the moment, China is not the only country with plans to explore deep space. NASA also reported that it had planned for a “Trident” mission to send a probe to Triton, but it was abandoned in the Decadal Survey of Planetary Science and Astrobiology 2023-2032. Instead, he seems to envision a “Uranus Orbiter Probe” mission to send a probe to Uranus and its moons.
Chinese research grouparound 2030By launching a spacecraft and using Jupiter’s gravity,2036It is expected to reach Neptune at several scheduled launch times, and at the latest2040It is said that it is necessary to reach Neptune by time.
Text / Misato Kadono
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