Astronomers Prepare a Mission Concept to Explore the Ice Giant Planets |
If you would design your dream mission to Uranus or Neptune, what would it not appear like?
Why decide only one, when you would do all of it?
Planetary scientists not too long ago designed a hypothetical mission to one among the ice large planets in our photo voltaic system. They explored what that dream spacecraft to Uranus might appear like if it included the latest improvements and cutting-edge applied sciences.
“We wanted to think of technologies that we really thought, ‘Well, they’re pushing the envelope,’” mentioned Mark Hofstadter, a senior scientist at the Jet Propulsion Laboratory (JPL) and California Institute of Technology in Pasadena. “It’s not crazy to think they’d be available to fly 10 years from now.” Hofstadter is an creator of the inner JPL examine, which he mentioned at AGU’s Fall Meeting 2019 on 11 December.
Some of the improvements are pure iterations of current know-how, Hofstadter mentioned, like utilizing smaller and lighter hardware and laptop chips. Using the most up-to-date methods can shave off weight and save room on board the spacecraft. “A rocket can launch a certain amount of mass,” he mentioned, “so every kilogram less of spacecraft structure that you need, that’s an extra kilogram you could put to science instruments.”
Nuclear-Powered Ion Engine
The dream spacecraft combines two space-proven applied sciences into one brand-new engine, known as radioisotope electrical propulsion (REP).
A spacecraft works very similar to every other car. A battery gives the vitality to run the onboard methods and begin the engine. The energy strikes gasoline by way of the engine, the place it undergoes a chemical change and gives thrust to transfer the car ahead.
In the dream spacecraft, the battery will get its vitality from the radioactive decay of plutonium, which is the most well-liked vitality supply for touring the outer photo voltaic system the place daylight is scarce. Voyager 1, Voyager 2, Cassini, and New Horizons all used a radioisotope energy supply however used hydrazine gasoline in a chemical engine that rapidly flung them to the far reaches of the photo voltaic system.
The dream spacecraft’s ion engine makes use of xenon gasoline as gasoline: The xenon is ionized, a nuclear-powered electrical subject accelerates the xenon ions, and the xenon exits the craft as exhaust. The Deep Space 1 and Dawn missions used the sort of engine however have been powered by massive photo voltaic panels that work greatest in the internal photo voltaic system the place these missions operated.
Xenon gasoline may be very secure. A craft can carry a great amount in a compressed canister, which lengthens the gasoline lifetime of the mission. REP “lets us explore all areas of an ice giant system: the rings, the satellites, and even the magnetosphere all around it,” Hofstadter mentioned. “We can go wherever we want. We can spend as much time as we want there….It gives us this beautiful flexibility.”
A Self-Driving Spacecraft
With REP, the dream spacecraft might fly previous rings, moons, and the planet itself about 10 instances slower than a craft with a conventional chemical combustion engine. Moving at a gradual velocity, the craft might take secure, long-exposure, high-resolution pictures. But to actually make the most of the ion engine, the craft wants onboard automatous navigation.
“We don’t know precisely where the moon or a satellite of Uranus is, or the spacecraft [relative to the moon],” Hofstadter mentioned. Most of Uranus’s satellites have been seen solely from afar, and particulars about their dimension and precise orbits stay unclear. “And so because of that uncertainty, you always want to keep a healthy distance between your spacecraft and the thing you’re looking at just so you don’t crash into it.”
“But if you trust the spacecraft to use its own camera to see where the satellite is and adjust its orbit so that it can get close but still miss the satellite,” he mentioned, “you can get much closer than you can when you’re preparing flybys from Earth” at the mercy of a greater than 5-hour communications delay.
That degree of onboard autonomous navigation hasn’t been tried earlier than on a spacecraft. NASA’s Curiosity rover has some restricted potential to plot a path between locations, and the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) can be ready to detect hazards and abort its pattern retrieval try.
The dream spacecraft could be extra like a self-driving automobile. It would know that it wants to do a flyby of Ophelia, for instance. It would then plot its personal low-altitude path over the floor that visits factors of curiosity like chaos terrain. It would additionally navigate round surprising hazards like jagged cliffs. If the craft misses one thing fascinating, properly, there’s all the time sufficient gasoline for an additional cross.
A Trio of Landers
With additional room on board from sleeker electronics, plus low-and-slow flybys from the REP and autonomous navigation, the dream spacecraft might carry landers to Uranus’s moons and simply drop them onto the floor.
“We designed a mission to carry three small landers that we could drop on any of the satellites,” Hofstadter mentioned. The dimension, form, and capabilities of the landers may very well be something from easy cameras to a full suite of devices to measure gravity, composition, and even seismicity.
The dream spacecraft might survey all 27 of Uranus’s satellites, from its largest, Titania, to its smallest, Cupid, solely 18 kilometers throughout. The mission crew might then determine the greatest manner to deploy the landers.
“We don’t have to decide in advance which satellites we put them on,” he mentioned. “We can wait until we get there. We might decide to put all the landers on one satellite to make a little seismic network to look for moonquakes and study the interior. Or maybe when we get there we’ll decide we’d rather put a lander on three different satellites.”
“Ice”-ing on a Cake
The scientists who compiled the inner examine acknowledged that it’s most likely unrealistic to incorporate all of those modern applied sciences into one mission. Doing so would contain a lot of threat and a lot of value, Hofstadter mentioned. Moreover, current space-tested know-how that has flown on Cassini, New Horizons, and Juno can actually ship thrilling ice large science, he mentioned. These improvements might increase such a spacecraft.
At the second, there isn’t any NASA mission into consideration to discover both Uranus or Neptune. In 2017, Hofstadter and his crew spoke with urgency about the want for a mission to one among the ice large planets and now hope that these applied sciences of the future may encourage a mission proposal.
“It’s almost like icing on the cake,” he mentioned. “We were saying, If you adopted new technologies, what new things could you hope to do that would enhance the scientific return of this mission?”
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