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Jan 21, 2022
Researchers from the Department of Space Dynamics and Mathematical Information Processing of the Institute for Space Research of the Russian Academy of Sciences have calculated a scenario for a mission to distant Sedna, a dwarf planet in the solar system whose orbit is beyond the orbit of Neptune.
In 2075, Sedna must pass its perihelion - the point of the orbit closest to the Sun. And it seems that today's humanity has a rare opportunity to send a spacecraft to this body and wait for the result. The next time the planet will come so close to the Sun only after 10 thousand years. "Meeting with Sedna" can give us truly unique information about the substance from which our solar system was built billions of years ago.
A team of researchers led by Vladislav Zubko and Alexander Sukhanov simulated a scenario for a space mission to study Sedna that could be sent into space in 2029-2037. An article analyzing possible flight trajectories was published in the journal Advances in Space Research and is available in the electronic preprint archive arXiv.org.
Image above: Orbit of Sedna at perihelion. Blue represents the orbit of Neptune. Orbit of Sedna at perihelion.
Sedna, a dwarf planet in the solar system, lies in the so-called scattered disk region between the Kuiper belt and the inner edge of the Oort cloud. It was discovered in 2003, when the planet was at a distance of about 80 astronomical units from the Sun (one astronomical unit, AU, is the average distance from the Earth to the Sun, a little less than 150 million kilometers).
The diameter of Sedna is estimated at about 1000 km (this is about half that of Pluto). A feature of Sedna is an exceptionally elongated orbit, a complete revolution in which takes more than 10 thousand years. At aphelion, the farthest point of its orbit from the Sun, Sedna leaves it at a distance of about 1000 AU, and at perihelion approaches "only" 76 AU. For comparison, Pluto has the same parameters at 49.3 AU. and 29.5 a.u.
Sedna is now approaching perihelion. And although the distance to it remains huge, nevertheless, humanity is already able to send a spacecraft there, and not only the descendants of its developers can wait for the results of such a mission. Researchers from IKI RAS took the launch of the mission in the period 2029-2037 as a starting point and estimated how long it might take to reach Sedna.
Sedna will still be within reach from Earth for quite some time, so theoretically you can go on an expedition in any year. In order to reach the planet "directly", it is required either to gain tremendous speed - beyond the existing possibilities, or to fly for a very long time - more than a hundred years.
In interplanetary flights, so-called gravity maneuvers are often used to solve the problem of gaining the desired speed. Passing near the large planets, the spacecraft, as it were, "borrows" part of their orbital energy and changes its speed and direction of flight as the creators need. As a result of the gravitational maneuver, it is possible to gain the required speed, consuming very little fuel. However, such schemes impose strong restrictions on the launch time - the planets must be in the "correct" configuration.
Image above: One of the mission scenarios. The launch of the device is on October 29, 2029, arrival to Sedna on October 25, 2059. Gravity maneuvers are provided for Venus, Earth, Jupiter, as well as one inclusion of engines to change the orbit during movement.
Studying the mission scenario, Vladislav Zubko, Alexander Sukhanov and their colleagues set limits on the speed that the device needs to develop, as well as on the total flight time - it should not take more than 50 years. They considered several schemes for gravity maneuvers using Venus, Earth, Jupiter, Saturn and Neptune. For each scenario, an increase in the speed that the device can receive during the flights, and the time during which it will reach the final goal - Sedna, was estimated.
It turned out that 2029 is the most “favorable” for the launch: with reasonable restrictions on the total fuel costs and flybys of Venus, Earth and Jupiter, the flight time to Sedna can be less than 18 years. With the same restrictions and the start of the mission in 2031 and 2034, the shortest flight time to Sedna will be 26 and 23 years, respectively. Launching in 2034 presents another possibility: in addition to flybys of Venus, Earth and Jupiter, a close flyby of Neptune could be used. However, this will lead to a decrease in the total fuel costs only with a flight duration of at least 27 years. Launches in 2033, 2036 and 2037 turned out to be energetically less profitable.
A possible mission scenario is determined not only by speed and fuel costs, but many other factors have to be taken into account. For example, when flying near Jupiter, its powerful radiation belts can damage the onboard electronics, so it is necessary either to provide the device with additional radiation protection, or to ensure the flight of Jupiter at a sufficiently large distance.
Artist's visualization of Sedna. Sedna has a reddish hue
The mission scenario does not provide for entering orbit around Sedna - this would require unacceptably large amounts of fuel. The device will fly near the dwarf planet, similar to the New Horizons probe that flew past Pluto in 2015 and explored this planet from a flyby trajectory. By the way, in a similar way, Halley's comet was studied from a flyby trajectory in 1986, including by the Soviet Vega spacecraft.
On its way to Sedna, the spacecraft could also approach some Main Belt asteroids and explore them along the way. Among the candidates for approach were such large asteroids as (20) Massalia (145.5 km in diameter) and (16) Psyche (253.2 km), their passage is possible when launched, respectively, in 2029 and 2034.
Dwarf planets and other objects outside the orbit of Neptune are distant, cold and practically unknown to us worlds. A flight to such celestial bodies can bring a lot of valuable information about the past of the solar system, since such objects are supposed to contain the "original" substance from which it was formed. And Sedna, as one of the largest trans-Neptunian objects known today, is of particular interest to scientists. The next visit of Sedna to the area accessible for observations from the Earth will have to wait more than 10 thousand years.
Source: IKI RAS.
Related links:
ROSCOSMOS Press Release: https://www.roscosmos.ru/33860/
IKI RAS: https://www.roscosmos.ru/tag/iki-ran/
Images, Text, Credits: ROSCOSMOS/IKI RAS/Wikimedia/Orbiter.ch Aerospace/Roland Berga.
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