Visions of the Future: Planetary Exploration Through 2050
When you’re striving to unlock the secrets of the universe, making plans 40 years in advance may not seem like a stretch. That’s why hundreds of visionaries from planetary science, astrophysics, engineering, and other disciplines came together Feb. 27-March 1 at NASA Headquarters—to break conceptual ground on humanity’s future in space.
Now is an especially important time to be having this kind of conversation. As one speaker pointed out, in the span of a human lifetime, we went from never having left the Earth to visiting almost every major type of body in the solar system. From our own moon to the dwarf planet Pluto to the ~3500 currently-known exoplanets beyond, the last 50 years of exploration have literally redrawn the lines that once proscribed our existence. From that vantage point, the Planetary Visions 2050 conference looked forward and asked: where do we go now, and how, and most importantly, why? What’s our grand hope, our grand plan, and our grand vision for where we want to be as a species in another half a century?
NASA’s head of planetary science Jim Green challenged attendees to think big, as the conference kicked off. “If you don’t spent time thinking about your future – dreaming about your future – you don’t have a future.”
As the discussion progressed, many visions of our best possible future in space emerged, with a few taking center stage. Major themes included our return to the moon and advancement onto Mars. Presentations ranged from planning explorations of asteroids and the outer planets to whether or not we need a definition of life to find it. Sessions focused on science’s role in galvanizing new technology and highlighted how commercial space ventures are rapidly changing what’s possible. Along the way, voices from all fields called for expanded diversity, inclusion, public outreach, and a unifying scientific theme.
In the end, several things were clear.
We Expect to Find Life Beyond Earth
Over the last 50 years, we’ve found some or all of the ingredients considered to be crucial for the formation of life on bodies as close as Mars and as far-flung as Rosetta’s comet C-G. Yet actual proof of life beyond Earth — either current or extinct — is pending. This is in part because definitive proof of life is a high bar to reach, particularly when spacecraft and landers with limited numbers of sensors and detectors have been sent to do the job.
Rather than struggle toward a definition of life that might get missed by even the most well-designed robotic missions, the community at the Planetary Visions conference discussed changing tactics: looking for signs of life processes rather than the life itself.
Whether a life-form is based on carbon or silicon, uses oxygen for energy transport like humans, or ingests iron like the first life on Earth may have, all life everywhere seems to have a few things in common. It uses energy. It transforms materials. It makes copies of itself and it curates information about how to make those copies. Searching for material actively undergoing changes that only a living organism can produce might allow us to see beyond what life looks like and witness what life behaves like, wherever it is in the universe.
Sample return missions
High hopes are set on sample return missions. From the moon to Mars to the asteroid Bennu, where spacecraft OSIRIS-REx headed in September 2016 to retrieve two ounces of material, bringing pieces of planetary bodies back to laboratories on Earth is more straightforward, and often less technically challenging, than flying a laboratory to them. Thus, over the course of the Planetary Visions conference, it was assumed that multiple sample return missions would be successfully completed well before 2050.
Obstacles to this vision remain, yet may be overcome sooner rather than later. For example, the lack of a launch date for a reflects an ongoing challenge in the astrobiology community: selecting the best place and the best way to sample.
As one attendee noted, it’s by no means straightforward question. For example, some of the best presumed spots to look for life on Mars include recurring slope lineae (RSL), which seem to be formed by that passage of water. However, even heavy and capable rovers have a hard time traversing sloped areas, and landing in one is inadvisable at best. Attendees at the conference were optimistic that constellations of lower-cost, easier-to-deploy small explorers, microrovers, and hoppers might increase the options for sampling locations while overcoming the challenges of uncertain terrain everywhere we want to look for life – which, ideally, is everywhere.
Eyes to Match Our Vision
To find life beyond Earth and to understand where life here came from, we want to be able to see further, into and through the atmospheres of planets like those around TRAPPIST-1. That depth of sight is going to require far better eyes in the skies than we have now. The Hubble Space Telescope – our trusty space telescope and long-time workhorse – has hit the limits of its resolution. Hubble, which was launched years before we found the first exoplanet, isn’t equipped to study details of those far-off atmospheres. Fortunately, the James Space Webb Telescope (JWST) is.
Designed for a new era where, as Dr. Shawn Domagal-Goldman put it, “I don’t count stars in the sky anymore – I count planets,” the James Webb will have the power to watch the TRAPPIST-1 planets for signs of life. Picking up oxygen and nitrogen around habitable-zone planets forty light-years away would be a significant find for JWST. Critically, as was discussed at Planetary Visions, finding oxygen in the atmosphere of an exoplanet doesn’t necessarily mean we’ve found life as we know it, or any life at all. Domagal-Goldman emphasized that’s what significant for life is, “The presence of oxygen or methane that requires replenishment in a way that only life can sustain.” In other words, levels that change over time as they do in inhabited environments.
While the scientific community anxiously awaits JWST’s deployment so we can test our hypotheses about life in the universe, planetary scientists and astrophysicists are already looking forward to the next big thing. LUVOIR, the next-next-generation telescope discussed at Planetary Visions, would be so powerful that it could provide direct imaging of rocky planets around other stars. By comparison, right now all we can see of these planets are their shadows crossing in front of their home stars. LUVOIR, which stands for Large Ultraviolet Optical and Infrared Surveyor, would show us the plumes erupting from distant icy moons with outstanding clarity and allow us to safely map asteroids – even relatively small ones – in our solar system to a relatively high degree. Those are only the few potentially life-saving and life discovering tricks up LUVOIR’s sleeve – more than enough for scientists who study everything from small bodies and planetary defense to cosmology to be excited.
Also exciting and highly theoretical: the possibility of using the sun itself to image distant exoplanets. This proposed solar gravity lens (SGL) would take advantage of how mass bends space, turning our own star into the lens of a cosmic-sized telescope. In order for this to work, the detector part of the SGL would need to be deployed on a spacecraft far from the sun –about 550 Astronomical Units (AU) away (for the sake of comparison, one AU is the distance from the sun to Earth, and Pluto is an average 40 AU away from the sun). On the plus side, at least in theory, that lensed images could have a resolution down to 10 kilometers (6.2 miles). That’s the equivalent of a city view with major highways and large parks, but on another planet.
Funding the Future
While we plan sample return missions and wait for our next round of space telescopes to come online, we are actively searching for ways to fund continuous human presence in orbit and beyond. The commercial space industry stands poised to cut down the cost of travel to space by reusing rockets, increasing the frequency of flights, and improving efficiency as we travel to and from orbit. But will that be enough to bring us into the next era of space travel, where people live and work in space by the hundreds, if not thousands?
Planetary Visions conference attendees suggested there is a lot that the private sector can do to help. For example, in addition to hundreds of millions of dollars made by lunar and asteroid prospecting, we might reasonably expect to see massive 3-D printed orbiting communications arrays coming online in the next 20 to 30 years. This engineering-driven need to expand telecommunications could help propel space from a 300 billion-dollar-a-year profit up to a $1 trillion enterprise by 2050.
Moon or Mars
Nothing beats an in-person appearance. Whether we’re heading for Mars with a manned flyby mission, or on our way back to the moon to re-earn our space-legs, a return to manned spaceflight beyond low-Earth orbit is in the offing. Questions about where will hopefully be resolved in the next few years. After that, the community of space visionaries at NASA will work out how.
Regardless of which planetary body we visit in what order, some attendees of Planetary Visions posited that combined of human-robotic ventures are the future for both types of programs.
“The human and robotic programs really should be connected,” said Bruce Jakosky, the head of the current MAVEN spacecraft mission studying Mars’ atmosphere. “They ARE connected.”
Wherever we head next, with humans or robotic missions or both, most of those present agreed that improved propulsion and power systems as well as far better communications arrays will be required before humankind can successfully take its place as a permanent, spacefaring species.
In Situ Resource Utilization and Planetary Protection
Earth isn’t what it used to be – not compared to how it was 50 years ago, and certainly not compared to how it was 50 million, 500 million, or 4 billion year ago when life here first emerged. Between then and now, there have been changes so profound that we can only begin to understand them by studying other places.
Being in the solar system that we are, though, means we’re in luck in more ways than one. Nearby planets Mars and Mercury are somewhat frozen in time. Without oceans, atmospheres, and active tectonics to alter their landscapes, these bodies remain relics and near-pristine examples of planetary geology from the days of our early solar system. Asteroids and comets are also early solar system remnants. Planetary protection groups like the one at NASA strive to maintain the integrity of these primordial bodies so we can understand our own origins and, hopefully, the origin of life itself.
At the same time, planetary visionaries acknowledge that surviving for any significant duration in space requires us to make use of the things we find there. Such In Situ Resource Utilization (ISRU) will allow us not only to survive by providing sources of water, power, fuel, and building materials, but it could potentially allow commercial space exploration itself to thrive through lucrative practices such as mining, either of asteroids or some other body.
Presumably, a balance between planetary protection and in situ resource utilization will one day be struck. From geochemistry to electromagnetism, from low-gravity physics to completely new kinds of chemistry, the focus at Planetary Visions was on the science required by both sides to further the exploration that will eventually benefit all. We know how important water is to life. The hope is that we can find life and enough spare water for humans to survive.
Exploring the Ocean Worlds
Everywhere we look on Earth from the deepest, darkest caverns to miles above the ground, we find life. So it is with high hopes that we look towards distant bodies like Europa and Enceladus – heated from within and covered by oceans. Attendees at the conference focused on the practical aspects of these searches. Specifically, if we want to explore the areas around Jupiter, Saturn, and bodies further out we need to leave soon.
Planetary visionaries have a plethora of ideas for ways to explore ocean worlds like Europa. These include flyby missions to help select research sites; landers to test the surface for biosignatures; modifying current Earth technology – specifically small submersibles – to travel as close to the ocean floors as possible in search of extant life; and even dropping explosives onto the surface to create an artificial plume and try to catch what comes out.
Forty Years Forward and Beyond
Exploring this universe of ours is truly a multi-generational effort. The technologies that we need to expand out into the cosmos as well as succeed here on Earth will grow out of the scientific and engineering requirements of the missions envisioned, adopted in the near future, and carried out by students just entering the field. As if to illustrate that point, during her talk on asteroid-hunting and the safety of Earth, Dr. Amy Mainzer displayed a photo of two 5-year-olds and announced, “These will be our planetary defense officers in 2050.”
Planetary visionaries like those who attended the conference last week look far – further than the visible horizon – in order to try and predict the kind of technologies we will need to build the kind of societies we will want in the kind of future we all hope to live in. Which goes first — the science or the technology — and where we go first, the moon or Mars or the asteroid belt, seemed less important at the end of the day than the fact that we are going. By exploring space, we are investing in ourselves and in our children. By inviting everyone — scientists and engineers, business people, artists and students of every extraction, age, and education possible — to come along, we improve not only our odds of funding and launching missions to space, but of designing ventures that reflect our values and goals as a society.
That’s the vision we all share.