A trans-Neptunian object is approaching the solar system, which will soon disappear from view for the next 11 thousand years. But NASA for some reason has no plans for a mission to him.
In 2003, scientists discovered Sedna, a trans-Neptunian object unlike any other. And although larger dwarf planets and comets were already found beyond Neptune, moving further away from the Sun, Sedna was unique in how far from the star it was. She was always more than twice as far from the Sun as Neptune, and as far away from the star as possible - at a distance about a thousand times more than the Earth. Despite all this, Sedna is quite large - about one thousand kilometers in diameter. This is the first object discovered, presumably to have reached us from the Oort cloud. And we will have only two opportunities to send a mission there: in 2033 and 2046. However, NASA is not even considering such a trip yet. If we do nothing further, this chance will slip away.
The solar system doesn't end with just gas giants, rocky planets and an asteroid belt. There is the Kuiper Belt, which contains countless icy bodies of various sizes, from dwarf planets like Pluto and Eris to comets and even smaller objects. Behind it is a scattered disk: bodies that once approached Neptune, but were thrown into more distant orbits, often located hundreds of astronomical units from the Sun (1 AU is the distance between the Earth and the Sun). Further, there are isolated trans-Neptunian objects: bodies that never approach any of the main planets and whose perihelion is greater than that of any object in the Kuiper Belt and the scattered disk. But the farthest are objects from the Oort cloud: they are in thousands of AU. from the Sun and denote the edge of the solar system.
The existence of the Oort cloud has not yet been proven, although there are fairly strong theoretical and indirect observational reasons to believe that it is real (for example, discovered comets with long and hyperbolic orbits). In theory, at a distance of about one thousand AU. up to one or two light years from the Sun, there should be a spherically distributed set of bodies formed in the early stages of the formation of the solar system. In 2003, a team that included Mike Brown, Chad Trujillo and David Rabinovich discovered the first candidate for objects from the Oort cloud, Sednu. Aphelios of Sedna is located at about 900 AU. - one of the most distant known to science. The object's perihelion is no less impressive 76 AU. Sedna never approaches any of the major planets, so gravitational force does not dissipate it.
Logarithmic view of the solar system extending all the way to the nearest star, also illustrating the Kuiper Belt and Oort Cloud.
So, many speculate that Sedna is one of the first objects we know from the Oort cloud. In the 15 years that have passed since its discovery, only one gray-like object has been discovered - 2012 VP113 with a perihelion of 80 AU. But the most compelling difference between them is their size: with its thousand kilometers in diameter, it is slightly larger than the dwarf planet Ceres. Sedna was discovered due to its size, brightness and reflective surface properties. At the moment, it is the only isolated object detected by direct observation. However, we were able to spot Sedna only because she approached her perihelion.
It takes Sedna about 11 thousand years to complete its orbit around the Sun. Today it is located at a distance of about 85 AU. from U. S. It is now moving towards the Sun and will reach perihelion in 2075. Given its size, orbital characteristics and origins, Sedna is often considered one of the most important trans-Neptunian objects discovered. And today we have a chance to send a mission to the outer solar system to reach Sedna when it approaches its perihelion. However, given the orbital features of all the planets in the system, we will have only two attempts - and very soon: in 2033 and in 2046.
Based on their orbital parameters, most trans-Neptunian objects fall into such well-known categories as the Kuiper Belt and Scattered Disc. Detached trans-Neptunian objects - rarity; most likely Sedna is the most exceptional of them all.
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The reasons for the mission are extremely simple. The inevitable approach of Sedna means that then we will not have the opportunity to study it at such a close distance for many thousands of years. And, as mentioned above, NASA does not even have research missions to Sedna under consideration. At the same time, the most energy efficient segment on the way to the object will be the gravitational assistance of Jupiter: we will be able to use this only if the mission is launched in 2033 or 2046. If we choose one of these windows, we can get to Sedna in 24.5 years. If sent in 2033, the mission will arrive at the end of 2057, when the object will be at a distance of 77.27 AU. from the sun. If the launch takes place in 2046, then we will reach Sedna in December 2070, when it will be a little closer - at 76.43 AU. from the sun.
Think how much we learned during the New Horizons mission: for example, what Pluto looks like, what its geology is and what its atmosphere consists of, about its ice, rocks, weather, studied its lunar system, topography - the list goes on for a very long time. Thanks to New Horizons, we have well studied the formation of the solar system and young objects on its outskirts. All of this was done with tools developed in the early 2000s.
A snapshot of the dark (night) side of Pluto, showing layers of atmospheric haze and, presumably, low-lying clouds closer to the surface. The technology with which the photos of Pluto were taken was developed more than ten years ago.
Now imagine that we get all this data about a completely new class of objects: about bodies formed far beyond the space in which the protoplanetary disk of the solar system was formed. Imagine what tools we will develop and what scientific questions we will answer if we prepare a mission in the 2020s or 2030s. This is the best opportunity for us - as a species and civilization - to explore one of the most unique objects approaching the Sun for the first time in many thousands of years.
Does the Oort cloud exist? Is Sedna very different from the objects that formed in the Kuiper Belt in its composition and geophysical properties? Does it come from the Oort cloud? Does it have atmosphere or companions? Does it rotate and does it have the elements necessary for life? By sending a mission to Sedna, we could get answers to these and many other questions. Any mission takes a lot of time to prepare, plan and execute - all the more so truly ambitious. And if we want to travel to Sedna as early as 2033, it's time to start planning now.
Vladimir Mirny