Last week the front-page of newspapers all over the world announced that Ultima Thule, a snowman-shaped object located 6.5-billion km from Earth, had been finally approached by Nasa’ New Horizons probe, becoming this way the farthest body in the Solar System to be visited by a spacecraft.

Looking at the gorgeous pictures of the rock, floating silently beyond Pluto, I could only think how far we have come in the exploration of space since we launched the first space probes just over 60 years ago. If we have done so much in just a few decades, what could the skies be holding for us in what remains of this century? As Yogi Berra put it, “it’s tough to make predictions, especially about the future” so I claim neither exceptional foresight nor particular creativity for this list of ten predictions that I wrote down when trying to answer that question:

1. All predictions will miss their deadlines.
2. Thousands of people will live in space.
3. We will find new business models for space exploration.
4. New space jobs will appear (most of them to be done on Earth).
5. Many big structures will be built in space.
6. We will find alternatives to chemical rockets.
7. Robots will have explored in depth every corner of the Solar System.
8. Humans will visit (a few) other places in the Solar System.
9. We will make the first attempt of an interstellar mission.
10. The Earth will remain the focus of our interest.

Below I give a brief explanation of each item in my list.

Let me know what you think about it. Is it too naïve or too obvious? Did I leave something out? I didn’t try to make predictions of specific research that could dominate astronomy or cosmology in this century – I don’t think anyone could do that, but let me know if you can think of something!

1. All predictions will miss their deadlines.

With the notable exception of the Apollo program, space exploration has been marked by overambitious timelines and expectations that have resulted in a long stream of missing deadlines. Back in the 1960s, it was expected that by the year 2000 there would be colonies in the moon and that humans would have already stepped in Mars, a vision that is still a few decades away from us (see prediction 8). Even on projects that are already funded and on the pipeline, the delays can be quite significant as we were reminded last year when the launch of the James Webb Space Telescope, initially planned for 2011, was yet again postponed to May 2020.

There are many good reasons why projects of such humongous complexity can be off by many decades, but this is an important point to keep in mind when imagining the future of space exploration. Read my own predictions with a pinch of salt and add generous 20 or 30 years more to any future date that I give in this entry.

2. Thousands of people will live in space.

More than 500 men and women have gone to space since Yuri Gagarin did his first flight in 1961. In the next 80 years many more will follow them, and by the end of the century, thousands of people will be living for prolonged periods in structures orbiting the Earth or built in other celestial bodies of the Solar System (prediction 6).

I’m not saying millions of people will be doing this, not even hundreds of thousands, but just a few thousands and most of them will be living in the Earth’s low orbit. Still, I think increasing the presence of humans in space by such a large order of magnitude will be the most critical driver to space exploration in what remains of this century. As more and more people make the trip to space, the views of what we should be doing there will change and will be shaped by people that are not the heroic astronauts, cosmonauts and taikonauts but rather more ordinary people, not very different from you or me.

3. We will find new business models for space exploration.

Up until recently, going to space was business of governments, which were the only ones with the financial muscle to embark in that type of high-risk endeavor. Things changed forever a few years ago when the Obama administration opened the door to commercial spaceflight and private-public collaboration for space exploration.

Private companies have already found two business models for going to space: tourism and cargo missions. Space X, Blue Origin and Virgin Galactic have serious aspirations to become big players in these industries, and I’m sure we will see a proliferation of competitors in the next couple of decades.

I am convinced that we humans have endless creativity and determination to overcome the pains and challenges of exploration, but I am even more convinced of our desire to make money. With more and more people traveling to space (see prediction 2), we will learn from entrepreneurs having new ideas to profit from space exploration. Some of these ideas will be just recycled versions of activities that we know work already, like that of mining asteroids for rare materials hard to find on Earth. The most disruptive ones, however, are impossible to name at the moment (did anyone think that advertisement would be the business model for internet a few decades ago?) but surely they will be the ones taking space exploration to new heights.

4. New space jobs will appear (most of them to be done on Earth).

Take any population of a few thousand people for a prolonged period, and you can be sure that sooner or later someone will sue someone else. With thousands of people living in orbit and in other planets (prediction 2), we can be confident that a new breed of space lawyers will appear.

Of course, not only specialized lawyers will be required to maintain such a large population away from Earth. We can imagine that they will also need dedicated designers, architects, engineers and doctors, all of them focusing on specific aspects of life in space. We can’t imagine yet what most of those new jobs will be like, only that they will be part of the larger pool of jobs of the future that don’t exist yet and that will replace many of the existing ones.

The vast majority of people working nowadays in jobs associated with space exploration are not astronauts. Extrapolating that proportion, I predict that in the future where thousands are living in space, millions of people will be working on Earth in those new space jobs.

5. Many big structures will be built in space.

The International Space Station (ISS) is the largest artificial object orbiting the Earth and with a price tag of $120bn, one of the most expensive structures ever built. Continuously occupied since 2000, it is big enough to be seen with the naked eye from Earth, proving that it is both a marvel of technology and international cooperation.

Many of the thousands of people living away from Earth in the future (prediction 2) will be doing so in the dozens of big structures orbiting the Earth and other planets. They might be bigger than the ISS but probably not by a significant factor. Still, we will be able to see many of them in the skies, but they will not surprise us more than flying airplanes do these days.

Other big structures will pop on our landscapes: Launching and landing facilities, or the famous Space Elevator, for example, will be common by the end of the century, bringing the feeling of a space-age closer to those living on Earth.

6. We will find alternatives to chemical rockets.

Modern rocket engines have their origins in the pioneering work of Robert Goddard in the 1920s, and though they have never stopped being improved by great engineers like Wernher von Braun, the basic concept remains the same: a propellant undergoes an exothermic chemical reaction that produces a hot gas that thrusts the rocket.

The fastest rockets built so far have reached insane speeds of 15 km/sec, allowing New Horizon, for example, to reach Pluto in less than 10 years. And though this is impressive, it is still not fast enough for maintaining a sustainable presence in Mars or beyond. Scientists have been working for decades on alternatives to chemical rockets, and the list of candidates is genuinely the stuff of science fiction movies: ion drive engines, solar sails, plasma propulsion engines, thermal fission rockets, antimatter-powered spaceships.

When I wrote the first draft of this entry, I didn’t have alternatives to chemical rockets among my predictions for this century. After all, we are talking about something that will require not only vast amounts of money and continuous research commitment but also the ideas of a few geniuses like Goddard and von Braun together with a few strokes of good luck. However, when I read more about this, I found that the efforts of researchers in this area have been serious and sustained for a long time, and that made me optimistic that by the end of the century we will construct super high-speed spacecraft that will start a new space revolution.

7. Robots will have explored in depth every corner of the Solar System.

In the first 60 years of space exploration, humans have sent dedicated space probes to every single big object in the Solar System, from the Sun to Pluto. The Moon has been the favorite destination of space missions, followed by Venus and Mars. For the other planets and their moons, however, the missions so far have been mostly for general recognition, collecting data of their surfaces, atmospheres, and environments. In the next few decades, the number of visits will increase by a full order of magnitude, and the missions will become much more specialized, with narrower and deeper goals.

 

Our understanding of the Solar System has gone through a complete transformation since we started receiving the pictures of alien landscapes located billions of kilometers away. Still, we have plenty of questions of the formation of the Solar System and its individual sub-systems, and the best way to find the answers is to go out there and collect more specific data that we can analyze here on Earth. Paradoxically, the answer of the origin of life in our own planet might also reside in those inhospitable worlds so far away, and exploring them might be the best way of finding it.

Thus, exploring the Solar System is a crucial quest for our race, and the most effective way of doing it is by sending unmanned spacecraft with robots that can resist the cruel conditions of outer space. As we improve the functionality of these robots, it will become more difficult to argue the need of sending humans to space – but still, many people will do it anyway (prediction 8).

8. Humans will visit (a few) other places in the Solar System.

Although robots will be ones doing most of the exploration this century (prediction 7), humans will increase their presence significantly in space (prediction 2). I think most of them will be traveling to low and medium orbits, perhaps as part of some tourist pack (prediction 3), but not a small fraction will be actually leaving the Earth’s gravitation field to go to other parts of the Solar System.

I’m sure I won’t be very controversial by saying that humans will go back to the Moon as early as in the decade of the 2020s. The question might be who is going to get there first: a private American company, a state-sponsored Chinese mission or someone completely different. A prediction of humans going to Mars this century won’t raise many eyebrows either, and getting there by mid-2030s is in the mind of everybody. I can see how by the end of the century we might have permanent stations in both bodies, perhaps similar to the ISS or slightly bigger (prediction 5).

Besides those two, other destinations for humans this century are a matter of speculation. I personally believe that a series of manned missions to Venus will happen around the same time the missions to Mars: not only is closer to Earth (it can take 3 months getting there, instead of the 7 months to Mars) but also is a fascinating place with its monstrous atmospheric pressure and its sulfuric acid rain. True, humans can’t land in Venus without suffering the most horrific death, but it is indeed possible to stay a few kilometers above ground in its atmosphere that, despite some minor inconveniences (say, its hot as hell), can be a magnificent place to visit and study.

What about the outer planets? A human-crewed mission beyond the asteroid belt will definitely depend on developing more powerful engines (prediction 6) and having a solid case for going there. With our current rockets, it would take between six years to get to Jupiter and ten years to get to Pluto, and a mission of such length would pose unacceptable risks to humans. As I don’t expect alternative engines to be fully functional, but until the end of the century, crewed trips to Jupiter and beyond will not happen before 2100.

9. We will make the first attempt of an interstellar mission.

Any mission targeting an object outside the Solar System seems to belong to the realm of fantasy rather than science. Having said that, I think it is inspiring to see real and serious efforts in that direction, which have been in the minds of scientists for a long time.

There are many designs for possible missions to the Alpha Centauri system, 4.4 light-years away from Earth but one that has caught some attention recently is the Breakthrough Starshot. It is envisioned as a fleet of a thousand tiny spacecraft, just a few centimeters in size each, using solar sails (prediction 6) that would be powered by laser light-beams fired from Earth.

 

The challenges of the Breakthrough Starshot are phenomenal, but there seems to be a genuine interest in making it work. It has had the backing of many science heavyweights of the like of Freeman Dyson, Stephen Chu, and the late Stephen Hawking, and has initial funding of $100m. As always, people are very optimistic of the timeline for Breakthrough Starshot, and there is speculation that it could be a reality in just a few years. I doubt it will happen so soon (prediction 1), but definitely, this and other alternatives will be attempted before the end of the century.

10. The Earth will remain the focus of our interest.

Some great minds of science and business have started to advocate space exploration as a last resource for the impending doom on our planet. With an always-increasing population, insurmountable global warming, and the perpetual threat of nuclear war, Earth is portrayed as a lost cause. According to these visionaries (and I don’t use that term with sarcasm) colonizing Mars is our only hope to perpetuate our species on the long run, so we better get working on it.

Perhaps I’m a hopeless optimistic, but I think, on the contrary, that as we better understand our planet, our chances of saving it will increase more and more, and by the end of the century we will have overcome the greatest challenges ever posed to the human race: climate change and the systematic destruction of the biosphere.

For decades, NASA, ESA, and Roscosmos have been thoroughly studying the Earth as a central part of their mission. From dedicated satellites and airplanes, they have been collecting data from our atmosphere, land, and oceans, giving us crucial elements to shape our understanding of our planet. In the next decades, this emphasis will deepen, and our enthusiasm for studying Earth will become stronger.

The spacecraft we have sent to all corners of our Solar System have sent us back breathtaking pictures of mountains, volcanoes, craters, valleys, dunes, and even rivers, located billions of kilometers away, evoking the ones in our own planet. These are images of entirely different worlds that spark our curiosity but remind us that Earth is the only place in the Universe that we can call home: This is where all our travels start and this is where we will return.