As the second most distant planet in the solar system, just now long would it take to get to Uranus? Which missions have been there before? And do we have any plans to go back? Let’s take a look.
Uranus was the first planet to be discovered in the ‘modern’ era. Even those that have exceptional vision and the ability to see it unaided, would struggle to tell it was a planet and not a distant star.
Uranus – Quick Facts
- Average Distance From The Sun: 2,873,550,000 km (1,785,541,189 mi)
- Radius: 25,559 km (15,881 mi)
- Temperature: -195 °C (-320 °F)
- Day length: 17 Earth hours
- Year length: 84 Earth years
- Number of moons: 27
- Closest Distance to Earth: – 2.6 billion kilometers
- Furthest distance to Earth: – 3.2 billion kilometers
- Next Window For Quickest Transit: – 2031 or 2032 for arrival in 2044 – 2045
How far is Earth from Uranus?
To determine how far the Earth is from Uranus, we need to take into account where each of the planets are in respect to their orbit of the Sun. The distance can very greatly as the planets move along their orbit.
The closest that Earth and Uranus approach each other is when both planets are in opposition. Opposition happens when the Earth moves between an outer planet, like Uranus, and the sun. This happens around once every 370 days. The closest approach that these planets can make, is when they are aligned in opposition, Uranus is at its closest position to the sun (perihelion) and Earth is at its farthest (aphelion).
At it’s farthest, in solar conjunction, Uranus can be as distant as around 3.2 billion kilometers from Earth. This happens when the planets are on different sides of the sun to each other. At it’s closest, in opposition, Uranus can be as distant as around 2.6 billion kilometers from Earth. It is nearly twice as distant as the next planet in, Saturn, even at it’s closest distance to Earth.
As Uranus and Earth both have elliptical orbits, the close and far points expand and contract over time, so these distances do vary.
- Next Opposition (closest distance to Earth): November 9, 2022
- Next Solar Conjunction (farthest distance from Earth): May 9, 2023
How Long Would it Take to Get to Uranus?
There has only been one mission so far to visit Uranus, and that itself was brief. It was from this mission that we know it has a retrograde orbit. That it is tilted on it’s side and has many moons.
Voyager 2 was the craft that visited Uranus, on it’s trip around the outer solar system. Most of it’s observations and data was collected in a mere 6 hours. The Voyager 2 probe was launched on August 20, 1977 and reached it’s closest approach with Uranus 3080 days (8 years, 5 months, 5 days) later, on January 24, 1986! At it’s closest approach, Voyager 2 came within 81,500 km (50,600 miles) before flying off further into the solar system.
Other than this mission, it is observations from powerful telescopes on Earth, and also Hubble that have added to our knowledge of this distant planet.
Placing a craft in orbit, or dropping a probe into the atmosphere could take considerably longer. The approach would need to be calculated to allow the craft to slow and enter orbit at an acceptable speed. Also, the fight time would depend on whether the launch window and position of the planets allows for a gravity assist from another planet en-route.
What is the Shortest Trip?
The shortest trip so far, was that of Voyager 2 as this is the only craft to have visited Uranus to date. While other missions to the planet are currently being proposed, it is likely that these would have a longer journey time. As a dedicated mission to the planet would have greater mission goals than can be achieved with a flyby, approach would in all likelihood be slower and considered. A craft will take several passes before slowing into a comfortable orbit.
How Often Does The Closest Approach Occur?
The closest approach between Uranus and the Earth happens once every 370 days. Due to the orbits however, the closest approach in 2022, will vary in distance from the closest approach in 2023, so there is a longer cycle in play here too.
Missions To Uranus
So far, there has only been one mission to Uranus, as mentioned above:
- Voyager 2 – Launched Aug 20, 1977 – Closest Approach Jan 24, 1986 – Flight Duration – 8 years, 5 months, 5 days. This mission was a flyby in which Voyager 2 collected data about Uranus, it’s atmosphere, moons and tilt. Many photographs were taken and this mission provided our first real look at the planet and its system.
The ESA, NASA and China have all got their sights on Uranus, but nothing passed the planning stage as yet. However, NASA has put Uranus at the top of its list of priorities.
This is following the most recent decadal survey, when is proposed every 10 or so years by the National Academy of Sciences. In the latest survey, scientists have recommended that the Ice Giants, and in particular the least explored planet Uranus, should be top of the priority table. There are many reasons for this, but foremost, is that we still have so much to learn about this planet and its many moons. The planet can teach us much about the further reaches of our solar system, and answer questions that have had to wait in line patiently for decades.
The proposal by the NAS committee, was for a multi-year, multi-funtional Uranus Orbiter and Probe (UOP). To study the planet, its system and its atmosphere. Depending on if the project is agreed, and on the flight window, we could see Uranus in a different season to that of the list visit – offering maximum contrast with previous observations.
If we want to catch Uranus in it’s southern spring, then we need to arrive before 2049. Ideally, with the alignment of Jupiter to provide a gravity-assist, we would launch a mission in 2031 or 2032. This would provide for the shortest flight time, and get us there in time for the season change. We could leave later, but if we waited until 2038 say, then the flight time would be pushed out to 15 years due to the alignment of the planets.
What Is So Exciting About Uranus?
The Ice Giants have a lot to teach us that we don’t already know about he solar system. Because of their distance, they have not had as many missions or investment as the terrestrial planets around us. It is not only the planet that is of interest though, it is also its moons. Some scientists believe that some of Uranus’s many moons – particularly Titania and Oberon – could be ocean worlds, underneath their thick sheets of ice, capable of hosting life. Anywhere in the solar system that can harbour life is undeniably worth investment in a visit.
How Far Is Uranus From The Other Planets?
The following are average distances between Uranus and the other planets in the Solar System:
- Distance From Uranus to Mercury: 2,815,640,000 km or 1,749,638,696 miles
- Distance From Uranus to Venus: 2,765,350,000 km or 1,718,388,490 miles
- Distance From Uranus to Mars: 2,645,610,000 km or 1,643,982,054 miles
- Distance From Uranus to Jupiter: 2,095,220,000 km or 1,301,969,708 miles
- Distance From Uranus to Saturn: 1,448,950,000 km or 900,377,530 miles
- Distance From Uranus to Neptune: 1,627,450,000 km or 1,011,297,430 miles