The National Academy of Sciences finally released its new decadal survey — and the votes are in for Uranus. The survey is an unofficial but influential temperature check-style analysis of NAS members’ priorities for NASA, the U.S. space agency. The new edition, Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, calls for, among other things, a dedicated Uranus mission and, if possible, an orbiter and lander on Enceladus, a small moon of Saturn believed to have a vast ocean under its ice shell. And where there’s water, there just might be life.
What’s new — The survey calls for several space missions to further the search for alien life in the next decade.
The priorities include:
- Continued support to the Mars Sample Return mission
- Five TBD low-cost Discovery-class missions
- A lunar polar rover called Endurance-A to study the terrain where NASA intends to one day set up a Moonbase
- Two to three medium-class missions — the same kind that gave us the Pluto flyby New Horizons mission and the asteroid retrieval mission OSIRIS-ReX.
The program lays out two different funding predictions — one optimistic, one modest. (The modest model factors in a 2 percent budget increase.) Among the priorities that should be paid for regardless of how the budget pans out are the Mars Sample Return (part of the current Perseverance mission), continued selection of the Discovery class missions (which are capped at $800 million), the development of Endurance-A, and the Uranus probe, although development wouldn’t start on this until 2028 under the modest-budget plan.
Near-Earth Object (asteroids and other assorted space rocks) missions also make the cut. The document proposes a survey and follow-up mission to an object of interest.
Here’s a breakdown of the most ambitious priorities for the NAS:
Like the Perseverance rover on Mars, Endurance-A is designed to cache lunar material samples — around 220 pounds in all. These samples will be picked up by NASA astronauts and returned to Earth for analysis to learn about the origin of the Moon and how it relates to Earth.
The hope is that these samples will enable new science on par with some of NASA’s most ambitious missions at just a fraction of the cost. It will depend in part on the Artemis program and NASA’s eventual lunar base, however.
In 1986, Voyager 2 passed by Uranus and its 27 moons. We haven’t been back, since, and as such, Uranus and neighboring Neptune (visited once in 1989) are the Solar System’s most ignored planets. Jupiter and Saturn both got large flagship missions, and we keep pelting Mars with robot after robot — it’s Uranus’ turn.
Like the Galileo mission to study Jupiter, the NAS proposes a Uranus mission involving an atmospheric probe that will plunge deep within Uranus. Both Uranus’ and Neptune’s composition are unlike anything else in the Solar System. They are made up of exotic forms of water termed, for lack of a better word, ices — though they’re remarkably hot and under intense pressure. This gives them the name “ice giants.”
Ice giants are believed to be scattered throughout the universe and are key to understanding what divides gas giants and rocky bodies.
There are several mysteries about Uranus such a mission could solve: What causes it to be tilted practically sideways? Why are its magnetic fields unlike any other planet in the Solar System? And what is the origin of its medium-sized moons?
The mission would need to launch in 2031 or 2032 to take advantage of an alignment with Jupiter that can increase the speed of the craft and make it arrive at Uranus sooner, however.
Where there’s water on Earth, there’s life — even deep below the ice shelf of Antarctica. Consequently, some of the few places on Earth that don’t have life are so devoid of moisture that nothing can thrive. This makes water a key ingredient in understanding life — and the best chemical we can think of to look for life elsewhere. (This is why every discovery of present-day water on Mars gets scientists excited.)
Enceladus is a dinky moon of Saturn’s, but all evidence points to it having an enormous ocean — with a lot of evidence coming from giant plumes of water shooting hundreds of miles into space, even forming a faint far-outer ring around Saturn. If you’re looking for life beyond Earth, there are few better places to start. (After all, there are already missions under development to the two other prime targets, Europa and Titan.)
The Enceladus mission concept — called an “Orbilander” in the document, which is somehow not a 1990’s electronica act — has two components: An orbiter and a lander. The orbiter would make repeated sweeps through the watery plumes, while the lander would spend two years on the surface, hunting for signs of life below. It will sit over the plumes and sample some as they’re ejected from the moon, as well as retrieve surface samples.
These samples will search for chemicals associated with life, including amino acids, lipids, polyelectrolyte, and cell-like morphologies. But of course, the mission may not see the light of day except under optimistic budget conditions.
Mars Life Explorer
The document calls for the continued funding of Mars Sample Return programs, but it also calls for a new mission, dubbed in the document the Mars Life Explorer. Unlike current efforts on Mars, which focus on past life, the Mars Life Explorer would search for present life on Mars by looking in icy areas with plenty of water. Or at least for a planet as barren as Mars.
“While ancient biosignatures are a focus of [Mars Sample Return], MLE will seek extant life and assess modern habitability through examination of low latitude ice,” the report reads. “MLE will characterize organics, trace gases, and isotopes at a fidelity suitable for biosignature detection; and assess ice stability and the question of modern liquid water via chemical, thermophysical, and atmospheric measurements.”
However, this mission, too, is only recommended with optimistic budget expectations.
Will the 2022 decadal survey missions happen?
Decadal surveys are a bit tricky — they aren’t really guidelines so much as recommendations, which Congress, the President, and NASA can opt to take up and fund, or ignore. But several survey recommendations made in the past have become full-scale NASA missions today, so the survey has a fair amount of weight.
That means that, while not all of these missions will happen, many of them could — meaning we could once again look at Uranus with a close eye, or dig in for some genuine alien hunting on Enceladus or Mars.