Bengaluru: NASA announced Thursday the four finalists for the next round of Discovery missions — two science missions to Venus, one to Jupiter’s volcanic moon Io and the fourth to Neptune’s unique moon Triton.
The four teams have been awarded $3 million to develop their mission plans over the next nine months. After the stipulated time period, each team will submit a study report to be evaluated for funding.
Of the four finalists, two will be funded to make their mission a reality. The final selection process is expected to take place next year.
The Discovery-class missions are considered to be small planetary missions and cost less than $450 million. They are meant to work in conjunction with the medium-budget New Frontiers missions (New Horizons, Juno) and the mega Solar System Exploration missions (Europa Clipper).
“Exploring any one of these celestial bodies will help unlock the secrets of how it, and others like it, came to be in the cosmos,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate.
The four missions
VERITAS or Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy, mission would fly to the neighbouring planet with the intention of mapping its surface.
It will also gather data about how the surface of the planet evolved and why Venus is so different from Earth despite being similar in size and mass. The spacecraft would have a synthetic aperture radar and would orbit the entire planet over different elevations, creating a 3D topographical map.
It would also investigate whether geological processes like plate tectonics and volcanism are still active today.
DAVINCI+ or Deep Atmosphere Venus Investigation of Noble gases, Chemistry and Imaging Plus mission will fly towards Venus’s atmosphere to understand how it formed and evolved.
It will determine if Venus, at any point in its past, had an ocean. The spacecraft’s descent sphere will plunge deep into the planet’s thick, extreme, greenhouse atmosphere and measure its composition.
The “+” in the name of the mission refers to the imaging project on the sphere, which includes cameras to map the surface and the clouds. Findings from this mission could potentially reshape our understanding of rocky planet formation.
The Io Volcano Observer will make its way to Jupiter’s moon — Io.
This moon is the most volcanic body in the solar system, covered globally by volcanoes. This is because Io’s internal structure is constantly heated up by the gravitational tug of Jupiter and its other large moons.
Io has not been studied well and this mission is expected to provide results on how magma is generated and the physics of its eruption through volcanoes. It will investigate the presence of a magma ocean beneath the moon’s crust.
Findings from this mission could also revolutionise our understanding of the evolution of terrestrial bodies as well as water bodies in our solar system.
Trident is not an acronym — it is a mission designed for Neptune’s largest moon, Triton.
Triton is the only moon in the solar system to orbit in the direction opposite to its planet’s rotation. It is considered to be a captured body, it did not evolve naturally with Neptune, but the gravity of Neptune pulled a body from beyond its orbit that was passing by and captured it.
The moon is geologically active but icy, spewing ice volcanoes called cryovolcanoes, and has the second youngest surface on the solar system because of this.
Its atmosphere has an ionosphere, which can potentially enable the existence of a water ocean under the icy surface. Trident would investigate all these processes, map the surface of Triton and determine the existence of a subsurface ocean — all with one fly-by.
NASA’s Discovery missions
NASA’s Discovery missions have seen their hits and misses in terms of returns, but they have provided valuable insight into our understanding of planetary science.
Some Discovery missions include the active Lunar Reconnaissance Orbiter (LRO) and the Mars InSight probe as well as the defunct Kepler space telescope.
In 2017, the Lucy and Psyche missions were also selected to study asteroids as a part of the Discovery programme.