As has been seen recently, with the recently reviewed data of Voyager 2, it was recently discovered that Uranus is actually losing its atmosphere! The full article can be found on the Phys.org website, but it only shows why humanity should revisit the outer solar system with dedicated orbiters. The New Horizons probe generated a lot of media because it was the first and only so far probe to visit Pluto. However, there have never been any orbiters to visit the outer solar system.
This is important because as the data from the Voyager 1 and 2 missions show, there are a plethora of things for us to still learn about Neptune and Uranus. We will talk about the case for Neptune later and focus in on the big questions about visiting Uranus.
Q: How long would it take for a probe to get to Uranus?
A: It took the Voyager probe 8.5 years to get to Uranus after launch, and it took the New Horizons spacecraft 9.5 years to get to Pluto. Therefore, it is a safe bet to say 8-10 years for a spacecraft to go from Earth to Uranus. But that doesn’t include the time it would take to slow down, as 8-10 years would be the time for the spacecraft to fly by the planet. To study the planet, a few more years would be required for Uranus to capture the spacecraft in its gravity. This assumes the proper planetary alignments would allow for the spacecraft to take advantage of planetary gravity assists.
Q: When was the last time Humanity visited Uranus?
A: It was in 1986 when Voyager 2 visited the planet.
Q: How long would it take to build a potential spacecraft?
A: It took approximately 5 years between awarding funding and launch for the New Horizons probe. Therefore, it can be expected to take a similar amount of time for the new spacecraft.
Q: What was learned last time humanity visited the planet?
A: When visited by Voyager 2, it was discovered that the planet had a magnetic field, the intense radiation in the planet, a high layer of haze that radiated large amounts of UV light, and the illuminated and dark poles, and most of the planet, show nearly the same temperature at the cloud tops. Interestingly Voyager2 discovered 10 new moons during its last pass.
Q: What would we learn about Uranus?
A: Most likely the spacecraft would study the atmosphere, interior, moons, rings, and magnetosphere in some form.
Potential Viable Missions To Uranus
If developed by NASA to the original specifications, the Space Launch System, would be able to launch 1.7 metric tons of unmanned payload to Uranus.
The MUSE spacecraft, which stands for Mission to Uranus for Science and Exploration, was a 2015 European concept for a dedicated mission to Uranus to study the atmosphere, moons, rings, and more. The mission would arrive and study the planet from 2044 to 2050. 
2016 saw the proposal of the OCEANUS mission, which presented in 2017 as a future New Frontiers Program mission. OCEANUS stands for Origins and Composition of the Exoplanet Analog Uranus System. The mission was developed to have an orbiter, which would enable a detailed study of the structure of the planet’s magnetosphere and interior structure that would not be possible with a flyby mission.
The ESA has proposed as part of the Cosmic Vision program the ODINUS, Origins, Dynamics, and Interiors of the Neptunian and Uranian Systems, space mission, which would provide two twin orbiters. These twin orbiters would be named Freyr and Freyja, in honor of the twin gods of the Norse pantheon, with a primary mission of studying Neptune and Uranus. If this mission is selected, ODINUS would launch in 2034.