At the beginning of this year, NASA scientists had to decide which missions should explore our Solar System. They chose four missions for further study from the 20 intriguing ideas submitted. From these, they will pick two to fund fully.
This is how NASA has done planetary science for decades, and the process has succeeded phenomenally. Yet, there is so much more we can learn about the Solar System.
MORE IDEAS FROM THE ARTICLE
Two emerging technologies may propel NASA and the rest of the world into an era of faster, low-cost exploration that would lead to more exploration and democratise access to the Solar System.
NASA had several goals with MarCO. The MarCOs proved that small satellites could thrive in deep space and stream data back home.
A few months after their mission ended, the European Space Agency announced that it would send two CubeSats on its "Hera" mission to a binary system.
Interplanetary small satellite missions spurred interest in the emerging new space industry.
Polish scientists believe they can build a spacecraft with a mass of 50kg or less that can take high-quality images of Mars and its moon, Phobos. It might also be able to study the Martian Atmosphere. Access to low-cost launch was a key enabler of the idea.
NASA/ESA spacecraft was launched in 1997 and reached Saturn in 2004. Since then its been orbiting around the planet and taking photos of the planets' rings, moons, and weather.
The Huygens and Cassini probes separated. Huygens made a trip to the moon Titan and landed on solid ground in 2005. Cassini is the first to orbit Saturn and study the system in detail.
Since 1960, dozens of spacecraft have been sent to Mars. It is difficult to send a spacecraft to Mars and even harder to land on the planet because of the thin atmosphere.
Data revealed the largest volcanoes in the solar system and one of the largest canyons yet discovered. Dust storms regularly sweep over the plains. Several spacecraft orbiting Mars shows an active planet rich in ingredients needed for life - water, organic carbon, and an energy source.