NASA Can Only Send Exploratory Missions To Either Uranus Or Neptune By 2040, But Not Both

NASA researchers and scientists from a few other US universities have devised plans to explore two of the most remote planets in our solar system; Uranus and Neptune. They¡¯ve rarely been studied, compared to other planets, and the team plans to change that within the next few decades.

Post encounter view of Neptune from the Voyager 2 - NASA

The team has released a report outlining four different types of missions that could be sent to Uranus and Neptune in the future, including spacecraft that could orbit the two planets for 10 to 15 years and even carry probes into their atmospheres.

The main focus of each of these missions is to determine what the planets are made of and how they came to be that way. ¡°The curious thing about Uranus and Neptune is that, although they look very similar, something about their interiors is actually quite a bit different,¡± UC Santa Cruz professor Jonathan Fortney, one of the report¡¯s authors, told The Verge. ¡°And we don¡¯t really know why that is.¡±

So far, only NASA¡¯s Voyager 2 has visited Uranus and Neptune. Launched in 1977, the spacecraft carried out flybys of the two planets, as well as Jupiter and Saturn, before heading out into deep space. It was thanks to the Voyager 2 that we discovered new rings and moons around Uranus and Neptune, as well as the fact that the former may have an ocean of water beneath its surface.

Voyager 2 - NASA

During the mission, the Voyager 2 came within 80,000 km of Uranus and 5,000 km of Neptune, the closest we¡¯ve ever been. However, that pass raised more questions than it answered, and NASA tends to tackle them sometime in the 2040¡¯s.

In 2015, NASA gathered scientists, including Fortney, to devise mission concepts for the two planets, which the team finally settled on; three missions to Uranus and one to Neptune. Uranus has more missions primarily because it¡¯ll be easier to reach than the latter. Each of the four missions is expected to cost approximately $2 billion, more than half the cost Cassini mission that sent the orbiter to Saturn. The three missions to Uranus would include a flyby and two orbiters, while the Neptune mission would also deploy an orbiter. Optionally, these planned vehicles will also be able to carry a probe that could be deployed into the atmospheres of the planets.

However, though the four missions have been proposed to NASA, only one is likely to be carried out. ¡°There¡¯s no way there¡¯d be money for more than one,¡± Fortney says. On top of that, the missions will take a long time to complete. The earliest possible launch window could be sometime between 2029 and 2023, after which it would take another 10 to 13 years before the spacecraft even reaches its destination. That means the earliest we can expect to see any data from a mission to Uranus or Neptune would be in the mid 2040s

However, spacecraft development takes a long time, so if NASA decides to actually progress with one of these missions it needs to begin planning right away. The scientific community is expected to meet again soon to discuss space mission priorities for the years ahead, a discussion which will probably play a part in NASA¡¯s own decision.