Every ten years, scientists decide which planetary research missions to develop for the next decade. The new Planetary Science and Astrobiology Decadal Survey 2023-2032 report, released today, will help identify those future missions, which could answer the most compelling scientific questions of the next decade. Get ready for more Mars exploration and an investigation of water on Saturn’s moon, Enceladus. Visits to other planets may also be in the works.
Identifying and prioritizing future missions is a gargantuan task. While NASA is at the forefront of making extraterrestrial research a reality, it can’t decide unilaterally which missions should be on the radar next. Instead, NASA’s Science Mission Directorate relies on scientists all over the country to propose research missions through the National Research Council (NRC). The NRC surveys the larger scientific community, asking researchers to submit the most significant scientific questions today in planetary science and astrobiology. Submissions to the so-called Decadal Survey also need to describe strategies for carrying out missions that can answer those questions.
The report lists 12 priority science questions that need answering. These questions focus on the formation of our solar system; delving deeper into planet and moon formation and evolution, including atmospheres, interiors of planets, and magnetospheres; investigating exoplanets; and searching for life in and beyond our solar system.
The report recommended returning to Mars to retrieve previously collected rock and soil samples, as well as adding new, top priority “flagship missions.”
One of those is an exploration of Uranus, an icy planet in our outer solar system. The mission, planned to launch in 2031, would send an orbiter and probe to the planet. Voyager 2 flew by Uranus in 1986, but we have not sent any missions there since. The new spacecraft would closely examine the planet, its atmosphere, rings, and moons. The mission would greatly add to our relatively scant knowledge of icy planets, the report states.
Another flagship mission promoted in the report is to Saturn’s moon, Enceladus, which is also an icy world. The Orbilander, a spacecraft equipped with special equipment to study the moon, would fly to Enceladus to check out its ocean and sample plumes of water erupting from its crust. The spacecraft, which could launch before 2040, would also spend time looking for signs of life.
Not all proposed missions will necessarily be approved, though; it depends on how much funding the participating research groups receive. “The decadal provides an underpinning to all discussions about the priority of missions and the commitment of resources within the scientific community, NASA, the White House, and Congress. It is used as both ‘sword and shield’: a means to rally the community around new projects and investigations, and also to defend current priorities against budget cuts or other threats,” according to The Planetary Society, a Pasadena, California-based nonprofit promoting space exploration. Even if budgets don’t allow for all of the projects, NASA and Congress tend to support “the very top recommendations.”
Take a look at the previous report, “VISION and VOYAGES for Planetary Science in the Decade 2013-2022.” The priorities included exploring Mars rocks, liquid methane rain on Saturn’s moon Titan, volcanism within Venus, oceans on Jupiter’s icy moon Europa, and more.
Some of the main missions laid out in that report are underway. For example, the 2020 Mars Perseverance Rover collected Martian soil and rock samples from the red planet. A new mission set out in the recently-announced decadal would move the previously collected samples from their location near Jezero Crater to a rocket. Then, the first-ever rocket launch from another planet would transport the samples into orbit around Mars, where a European Space Agency orbiting spacecraft would pick up the sample-return container and bring it to Earth. Most likely, this mission would happen in 2028.
Planetary scientists are eager to evaluate Martian material because the planet is the only other one in our solar system that experienced similar geological processes to Earth during its formation, meaning it could have harbored its own life forms. “Discoveries on the surface of Mars point to an early warm, wet climate and perhaps conditions under which life could have emerged,” the executive summary of the 2013-2022 report states. While we do have Martian-origin meteorites on Earth, these are only of the igneous variety, whereas spacecraft observations on Mars have found sedimentary rocks that have apparently been shaped by water at some point, the report states. “It is these materials, none of which are found in meteorites, that provide the opportunity to study aqueous environments, potential prebiotic chemistry, and perhaps, the remains of early martian life,” the report explains.
To that end, the Mars Life Explorer mission is slated to look for evidence of life on Mars, launching sometime in the mid-2030s. The lander would drill into water ice deposits to take samples that could contain the first life signs on a planet other than Earth.