Astronomers think about flights to giant icy planets

Astronomers think about flights to giant icy planets
Astronomers think about flights to giant icy planets

What could be a flight to a giant ice planet? You can explore the unattractive surface of Uranus' moon Miranda, or explore the strange massive rings of Neptune. Recently, planetary scientists have designed a hypothetical flight to one of the icy planets in our solar system.

If you had the opportunity to simulate your cherished flight to Uranus or Neptune, what would it look like?

Would you explore the unattractive surface of Uranus' moon Miranda? Or maybe the strange and massive rings of Neptune? Or the amazing interaction of these planets with the solar wind?

But why choose one single goal when you can do everything at once?

Recently, planetary scientists designed a hypothetical flight to one of the giant ice planets in our solar system. They figured out what a dream spaceship flying to Uranus should be, taking into account the latest innovations and the most advanced technologies.

“We wanted to come up with technologies that really broaden our horizons,” said Mark Hofstadter, senior fellow at the Jet Propulsion Laboratory and California Institute of Technology in Pasadena. "It's not crazy to think that they will appear in 10 years." Hofstadter is the author of an internal study by the Jet Propulsion Laboratory, which he shared on December 11 at the fall meeting of the American Geophysical Union.

Some innovations are natural incarnations of existing technologies. Hofstadter talks about small and light hardware and computer chips. By using the most advanced systems, it is possible to reduce weight and free up a lot of space on board the spacecraft. "The rocket can put a certain mass into space," he says, "and therefore every kilogram of construction saved allows additional scientific instruments to be supplied."

Nuclear ion engine

The Dream Spaceship contains two well-established technologies in space that, combined, have yielded a completely new engine called the Electric Power Plant (ESRP).

A spaceship works just like any other machine. The battery provides energy to power the onboard systems and start the engine. The fuel travels through the engine, where a chemical reaction takes place and a reactive force is generated that propels the ship.

In the dream spaceship, the battery is powered by the radioactive decay of plutonium, which is the preferred energy source when flying in the outer solar system, where there is little sunlight. Voyager 1, Voyager 2, Cassini and New Horizons all had a radioisotope power source, but used hydrazine fuel in a chemical engine that quickly propelled them to the far reaches of the solar system.

The ion engine uses xenon gas as a fuel. Xenon is ionized. The electric field accelerates the xenon ions, and they leave the spacecraft in the form of exhaust gas. The Deep Space 1 and Don spacecraft used this type of engine, but they got their power from large solar panels that work best in the inner solar system, where most of the space travel takes place.

Xenon gas is very stable. The spacecraft can transport large quantities of it in pressurized containers. This allows the flight duration to be extended.“ESUR gives us the opportunity to explore all areas of the giant ice system: rings, satellites, and even the surrounding magnetosphere,” said Hofstadter. - We can fly wherever we want. We can spend as much time there as we need. This gives us great freedom of action."

Unmanned spacecraft

A dream spaceship with an ESUR installed on it can fly past the rings, moons and the planet itself 10 times slower than a device with a conventional chemical combustion engine. Moving at low speeds, the dream ship can capture crisp, high-resolution, long-exposure shots. But in order to use all the capabilities of the ion engine, the spacecraft needs onboard navigation automation.

“We don't know exactly where the satellite of Uranus is, and where the spacecraft is [in relation to this moon],” Hofstadter said. Most of the satellites on this planet are visible only from afar, and details about their size and orbits are unknown. “Because of this uncertainty, you must always keep a good distance from the object you are looking at so as not to crash into it,” he added.

“But if there is confidence that the spacecraft will see the location of the satellite with the help of the camera and correct its orbit, then you can get close to the satellite and not crash into it,” the scientist noted. "You can get a lot closer than when you are preparing a flyby from Earth, because in this case the communication delay is more than five hours."

There was no autonomous navigation equipment of this level on spacecraft before. NASA's Curiosity all-terrain vehicle has a limited ability to plot a trajectory between two points. And the OSIRIS-Rex interplanetary station will be able to detect hazards and stop sampling.

The dream ship will be more like an unmanned vehicle. For example, he will know that he will have to fly around the satellite of Uranus, Ophelia. It will prepare for itself a low trajectory above the surface to visit interesting places, such as the territory of chaos. Also, this ship will maneuver, flying around unexpected obstacles such as sharp cliffs and rocks. If he misses something interesting, he will have enough fuel to make another pass.

Trio of descent vehicles

Having gained additional space thanks to compact electronics, as well as the ability to fly slowly and low above the surface, which will be provided by ESUR and an autonomous navigation system, the dream ship will be able to take on board descent vehicles that can be easily dropped onto the surface of Uranus satellites.

“We designed a flight with three small descent vehicles that could be landed on any of the satellites,” Hofstadter said. The size, shape and capabilities of these devices can be anything from simple cameras to a complete set of instruments to measure gravity, soil composition and even seismicity.

The dream spacecraft will be able to survey all 27 moons of Uranus, from the largest Titania to the smallest Cupid, which is only 18 kilometers in diameter. The team can then decide how best to use the lander.

“We don't have to decide in advance which satellites to land them on,” Hofstadter said. “We can wait until we get there. We can land all vehicles on one satellite, creating a small seismic network to search for lunar earthquakes and study its insides. Or maybe we will decide that it is better to land these vehicles on three different satellites."

Icing on the cake

Scientists who have conducted internal research admit that it is simply unrealistic to include all these innovative technologies in one flight. It will be very risky and expensive, says Hofstadter. Moreover, the space-tested technology used aboard the Cassini, New Horizons and Juno could well make fascinating scientific discoveries on the ice giants. And innovation will complement this hardware.

NASA is not currently preparing for flights to Uranus and Neptune. In 2017, Hofstadter and his colleagues talked insistently about the need to fly to one of the ice giants, and now they hope that the technologies of the future will inspire someone to develop a proposal for such a flight.

“It's almost like the icing on a cake,” he said. "We said that if you apply new technologies, you can do a lot of new things, and this will ensure great scientific success."

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