MOSCOW, Mar 17, Vladislav Strekopytov. In NASA's strategic plan for planetary exploration, the number one priority is to fly the UOP robotic station to Uranus. The scientific community has been waiting for this for thirty years. About the features and tasks of the mission — in the material.
The most important flight of the decade
Uranus and Neptune are ice giants. Unlike the rocky inner terrestrial planets and the hydrogen and helium gas giants Jupiter and Saturn, they are formed by frozen water, ammonia and methane.
These planets are the most distant planets in the solar system and have been studied very bad. Ground-based telescopes can only see vortices in a dense atmosphere. The surface is completely hidden.
Of the spacecraft, only Voyager 2 flew past them in the late 1980s. Thanks to this mission, scientists received the first information about the composition of the atmosphere of Uranus and Neptune, their satellites. We learned that the planets have a magnetic field and weakly expressed rings. However, this is clearly not enough.
NASA has been planning to send a Uranus Orbiter and Probe (Uranus Orbiter and Probe) to Uranus for a long time. In the ten-year strategy for 2013-2022, this project was in third place in priority after the Mars 2020 rover and the mission to Jupiter's moon Europa.
The Perseverance Mars rover is successfully working on the Red Planet, collecting rock samples and preparing them to be sent to Earth. The launch of the Europa Clipper is scheduled for the end of 2024. In a 10-year review recently published by NASA, the lack of knowledge about ice giants is the main problem in planetary exploration, and the UOP mission is the highest priority project. » media-type=»photo» data-crop-ratio=»0.562121212121212″ data-crop-width=»600″ data-crop-height=»337″ data-source-sid=»» class=»lazyload» lazy= «1» />
Eight years before Uranus
The concept, developed by scientists and engineers from NASA, the University of California and Johns Hopkins University, involves sending a spacecraft weighing about five tons to orbit Uranus with a detachable probe that will plunge into the atmosphere of the planet. Design will start this year. The delivery vehicle is SpaceX's Falcon Heavy launch vehicle.
There is also a competing project Neptune Odyssey. But experts agreed that there is no necessary launch vehicle for it yet. In addition, the mission to Uranus is more flexible in terms of the choice of trajectories.
The launch will take place in 2031 or 2032, after 13 years the ship will reach its destination and spend about five years in orbit.
Alternative technical solution allows you to reduce the flight to eight years and, accordingly, double the useful life of the apparatus. It uses the effect of aerocapture: the spacecraft, slowing down in the upper atmosphere, enters the final orbit in just one pass. Usually several corrective turns are required.
But this option is unlikely to be chosen. It requires accurate data on atmospheric parameters, and they will be received only after the UOP mission. crop-ratio=»0.791245791245791″ data-crop-width=»600″ data-crop-height=»475″ data-source-sid=»cc_by-sa_40″ class=»lazyload» width=»1920″ height=»1519 » decoding=»async» />
Mystery Planet
Uranus practically «lies on its side» relative to the general plane of motion of the planets of the solar system. At the same time, it rotates around its own axis retrograde, that is, in the opposite direction.
This oddity is usually explained by the hypothesis that Uranus once collided with a large cosmic body. However, none of the satellites, inextricably linked with the parent planet, has the same inclined orbit. In addition, all the moons of Uranus are icy, and a powerful impact capable of overturning the planet would give so much heat that the ice would evaporate and the moons would become rocky.
There are many ambiguities with the internal structure. The Standard Model assumes that Uranus consists of three parts: in the center — a small stone core, then — an ice shell, outside — a hydrogen-helium atmosphere. However, some facts baffle scientists.
First of all, the thermal radiation of Uranus is much weaker than that of other giant planets in the solar system, including Neptune. This makes it difficult to determine the physical parameters of the subsoil. Perhaps in the upper layers of Uranus there is a certain layer that prevents heat from escaping. Or the main mass of the planet is composed not of ice in the generally accepted sense of the word, but of a superdense liquid — a mixture of water, ammonia and methane. By the way, if we assume that there is liquid water in the bowels of Uranus, this automatically moves it to the list of planets where life is possible. whirlwinds in the atmosphere.
Looking for answers
A mission to Uranus should answer many questions. The probe will study the change in atmospheric composition along the vertical, thermal stratification and wind speed depending on the height above the surface. And the orbiter will be engaged in global observations of the planet's atmosphere and magnetosphere, spectral and dynamic parameters.
A three-component magnetometer on board maps magnetic anomalies on the surface, studies the structure and dynamics of the magnetic field. Scientists want to understand the dynamo process by which it occurs.
The magnetic field of the terrestrial planets is generated in a molten metal core. In what form is the substance in the core of Uranus, is unknown. Recently, it turned out that the cores of Jupiter and Saturn do not have clear boundaries. Reaching the critical mass, the substance diffuses. This is how heavy elements from the center of the planet get into the outer shells up to the atmosphere. =»0.725162488393686″ data-crop-width=»600″ data-crop-height=»435″ data-source-sid=»» class=»lazyload» lazy=»1″ />
Perhaps the same is happening on Uranus — and its complex magnetic field is associated not with the core, but with convective flows in the liquid subsurface shell surrounding the inner icy part of the planet with a stable layered structure.
Researchers hope that the information collected by the UOP mission will allow us to get closer to unraveling how Uranus was formed and acquired its unusual tilt with retrograde rotation, to find out the volumetric composition of the planet and how it changes with depth. In addition, scientists plan to study the moons of Uranus in detail, understand the ratio of stone and ice in their structure, deal with internal sources of heat, and also find, possibly, underground oceans.
27 moons of Uranus are known, among them five large ones: Miranda, Ariel, Umbriel, Titania and Oberon. Indirect signs of ongoing geological activity were recorded on three — Titania, Oberon and Ariely. The latter is considered the most promising from the point of view of searching under the outer ice shell for an ocean of liquid water potentially suitable for the emergence of life.