Space Exploration

Is Humanity Ready to Realize the Dream of Interstellar Travel?

For generations, humans have dreamed, speculated, and theorized about the possibility of journeying to distant stars, finding habitable planets around them, and settling down. In time, the children of these bold adventurers would create a new civilization and perhaps even meet the children of Earth. People could eventually journey from one world to another, cultures would mix, and trade and exchanges would become a regular feature. The potential for growth that would come from these exchanges – intellectually, socially, politically, technologically, and economically – would be immeasurable.

Expanding humanity’s reach beyond the Solar System is not just the fevered dream of science fiction writers and futurists. It has also been the subject of very serious scientific research, and interest in the subject is again on the rise. Much like sending crewed missions to Mars, establishing permanent outposts on the Moon, and exploring beyond cislunar space with human astronauts instead of robots – there is a growing sense that interstellar travel could be within reach. But just how ready are we for this bold and adventurous prospect? Whether we are talking about probes vs. crews or technological vs. psychological readiness, is interstellar travel something we are ready to take on?

This was a central question raised at a public outreach event aptly named “Interstellar Travel: Are We Ready?” that took place at the 8th Interstellar Symposium: In Light of Other Suns, held from July 10th to 13th at the University of McGill in Montreal, Quebec. The symposium was hosted by the Interstellar Research Group (IRG), the International Academy of Astronautics (IAA), and Breakthrough Initiatives – in coordination with the University of McGill – and featured guest speakers and luminaries from multiple disciplines – ranging from astronomy and astrophysics to astrobiology, geology, and cosmology.

This public outreach event, organized by Prof. Andrew Higgins (Mechanical Engineering) and the McGill Interstellar Flight Experimental Research Group, occurred on July 10th from 7:30-9:30 PM EST. The event was open to the public and made available for free via a live stream. It was chaired by famed author and NASA scientist and technologist Les Johnson and featured a panel of noted scientists, educators, and space exploration advocates who offered an array of perspectives on this very question. The panel included:

After each panelist provided a brief introduction of themselves and their perspectives, a general discussion on the issues of interstellar travel was raised, followed by a Q&A session towards the end. Throughout, the panel addressed the chief challenges in realizing interstellar travel, be they technological, psychological, ethical, social, economic, and the like. They also addressed the likely implications, possible solutions, potential timelines, and whether or not humanity is ready to shoulder the associated burdens. As Les Johnson told Universe Today via Zoom:

“I introduced all the panelists, AJ, Allen, Phillip, and Erica. And then Trevor was like the emcee. He’s apparently a popular host in Canada. And does this kind of thing all the time. He’s witty, he’s personable, and so he interacted with the audience, had a list of questions, and we, on the panel, kind of batted around the answers. Some were specific to us, and some were general. And it all centered around this notion of, ‘How do we plan for something that’s far out?’ ‘Why are we doing it?’ Can we really afford to do it, and what’s the scale that it will be?” And there were differences of opinions.”

Going Interstellar

As we explored in a previous article, it would take between 19,000 and 81,000 years to reach the nearest star (Alpha Centauri) using conventional propulsion methods. It’s easy to see why space and advanced research agencies have been exploring concepts that could allow for much faster transits since the dawn of the Space Age. Nuclear-Pulse Propulsion (NPP) was an early idea, where fission reactions (nuclear warheads) or the fusing of deuterium or hydrogen fuel would be used to accelerate a spacecraft to a fraction of the speed of light (aka. “relativistic speeds”).

Many historic studies have been conducted, including Project Orion (1958-1963), Project Daedalus (1973-78), the Enzmann Starship (1973), Project Longshot (1987-88), Project Hyperion (2011), and Project Icarus (2009–14). Anti-matter propulsion is another concept that has been explored, which resulted in proposals like Project Valkyrie (2009). There have even been attempts to research Faster-Than-Light (FTL) propulsion, the most notable of which is arguably the Alcubierre Warp Drive, originally proposed by Mexican physicist Miguel Alcubierre in 1994.

Since 2000, proposals and design studies for ra DEP spacecraft have included Sun-Diver, Project Dragonfly, and (most notably) Breakthrough Starshot. This latter effort, announced in 2016, envisions a fleet of lightsails and nanocraft (the StarChip) accelerated by a 100 Gw laser array to 20% the speed of light. If realized, these spacecraft could accomplish a one-way journey to Alpha Centauri within 20 years (“in our lifetime”) and acquire pictures and data on any exoplanets that happen to be there. These evolving studies show how far the field has come, which Les Johnson noted in his introduction:

“When I first got involved in thinking about interstellar flight, I had been at NASA for about 10 years and was introduced to this community. And the annual gathering of this community was in this little town in Italy, and they met under the guise of being a project or a gathering of scientists talking about ultra-deep space missions. And the reason they did that was because they couldn’t say the word interstellar. Because people didn’t take it seriously…

“There are all sorts of challenges. If we’re ever going to send robots and people, we have to have power [and] communications. If you talk about seeing people, you have to keep us alive, or our progeny. It might be generations of ships. So the challenges are immense, and people didnt’ take it seriously. But there’s been a rapid progress in a lot of the technologies. And I firmly believe we will be launching our Ifirst robotic probes that travel faster than Voyager within the lifetimes of some of the people who are alive today that might get trip time to some of the nearest stars in 100 years.”

In addition to technological developments, the idea of interstellar travel has also received a boost, thanks to developments in other space sectors. These include renewed lunar exploration in this decade – the Artemis Program, the International Lunar Research Station (ILRS) – and proposed missions to Mars, which include NASA and China’s plans and commercial proposals by SpaceX. Of course, in addition to the challenges, many ethical, legal, and philosophical implications need to be addressed in advance. To this end, the eclectic panel of experts from various fields offered a good rundown and examinations of the particulars. As Erika Nesvold told Universe Today via email:

“I think each of the panelists talked about the big challenges that we each foresee in the future as humans attempt to send technology to other stellar systems and to live long-term in space. Some of us (like Phil) thought that the energy or cost requirements would be insurmountable. Some of us (like me and AJ) wanted to draw attention to the ethical problems we have yet to solve with astronaut selection, spacecraft design, inclusion, safety, etc. I think all of us are excited about humanity’s future in space, though, and want to see people working on these problems.”

Artist’s impression of astronauts on the lunar surface, as part of the Artemis Program. Credit: NASA

So… Are We?

First, there’s the elephant in the room, which means acknowledging the answer to the big question, “Are we ready?” According to the panelist, the answer is no. Interestingly, this was the one matter that all sides agreed on. Whereas they stated with a fair degree of confidence that robotic missions – a la Breakthrough Starshot – could be realized in the not-too-distant future, the possibility of crewed missions to nearby stars remains a far-off prospect. Said Johnson:

“No, we’re not ready. And it’s technology that’s the prohibitor. But we did conclude that being ready, at least for small robotic missions, is within reach. With the work that Breakthrough Starshot is doing and the spin-offs that might come from that, we all kind of envisioned that it might be possible to send a robotic probe within the next 100 years, give or take. So we’re not as far away from being able to do that as I thought we were when I began my career and looked at interstellar stuff like 20 years ago. I was thinking it was two to three hundred years. We might actually be within one-hundred years from our first robotic probe, which is amazing.”

According to Johnson’s estimates, robotic missions to the nearest star systems could be possible within 100 to 200 years. In the meantime, there are other things we need to be focusing on, things that are more achievable and within our intellectual and creative capacity. In addition, Link raised the question of motivations and values as a barrier, which require serious consideration before attempts at interstellar travel can occur. As Link told Universe Today via email, the transition between interplanetary and interstellar missions (often raised in this context) will not necessarily be a smooth one:

“I think interplanetary journeys are going to be a lot different than interstellar journeys. Mostly because it’s conceivable that most interplanetary journeys within our Solar System will happen within a person’s lifetime – it takes multiple generations to get to a different star. And so I think the values for an interstellar mission are going to be – or should be, at least – very different than an interplanetary mission. In terms of crew selection, monetary systems, if there is a monetary system, that determines resource sharing. I think all those things are going to have to be vastly different for an interstellar mission.”

Cost Assessment

Another major point was the energy requirement, which comes up in any discussion about interstellar travel sooner or later. Like it or not, an interstellar mission only makes sense (from an economic perspective) if it can be done in a person’s lifetime. That, unfortunately, is where the technological prohibition Johnson addressed comes up. As part of the panel discussions, Lubin raised a cost analysis he had previously conducted that concluded that the energy requirements are not currently within our grasp.

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity’s first interstellar voyage. Credit:

According to Lubin, directed-energy propulsion has tremendous potential for interplanetary (Mars in 30 days) and interstellar travel since it is the only technology that can achieve relativistic flight (a fraction of the speed of light) in the foreseeable future. Alas, the applications we can realize now are limited to beaming power from space (or between the Earth and the Moon) and optical communications. On this point, Johnson raised some objections.

“I personally think it’s an irrelevant number because by the time we do this, what is the energy price going to be?” he said. “And what is money going to be? So there are some definite differences.” In the meantime, as Stern eloquently summarized, the technology offers a roadmap that could lead to interstellar exploration someday:

“We’re an aspirational species. An aspiration of many human beings is to see our species explore very far away from our cradle, the Earth. But also, I think the other side of that coin is that you have to start somewhere. If you don’t have the aspiration, and you don’t start to make a plan and say, ‘Well, how do I go about that, what do I have to invent,’ you’ll never get it underway.

“I really believe that the 2020s – and the 20-teens, to some extent – really are the inflection point where Star Trek begins. We are living in an era that people will look back [on] in the 24th and 25th century and say, ‘That’s where spaceflight took off.’ And by having goals that are not just what we can do in this decade, or the next decade, or even in this century, we can actually start to chart a path to the stars.”

Who Gets to Go?

Another important issue when talking about the future of space exploration is access. As Link emphasized, there are so many different people participating in space and who want to participate in space, and they all have different dreams and goals. And, he said, it’s really important to understand this when planning and building projects that will attempt to reach other worlds:

“When you think about accessibility, the example that’s really tangible for folks: it’s a lot easier to build something that’s accessible than to retrofit it. It’s also a lot cheaper to do it from the beginning and design it as accessible from the beginning than having to go in and redo it. And so when we talk about the conversations, I think of the same thing.

“In space, it is complicated, disabling; we’re going to get things wrong because you can’t know the answers, and horrible things are going to happen. But the idea [is] that we are preparing for as many situations as possible and in as many ways as possible. Because we have the time, we can really be thoughtful about how we’re creating the new future that we want. That’s why I think that it’s important to start the conversations early.”

The 8th Interstellar Symposium outreach panel (from left to right): Les Johnson, Alan Stern, AJ Link, Erika Nesvold, and Philip Lubin. Credit: IRG/McGill University

Several other ethical implications were raised, which Nesvold addressed in her recent book, Off-Earth: Ethical Questions and Quandaries for Living in Outer Space. During the outreach event, she raised an issue that frequently comes up in the context of space ethics: “Should we settle space?” As she related, there are many people she’s encountered who make persuasive arguments that either humanity should not create permanent human settlements ever or that we should wait until we’ve matured as a species. While Nesvold doesn’t share these particular views, she did acknowledge the importance of open discussion to address the many fears and concerns. As she explained via email:

“I’m an astrophysicist (so I have a technical background like Alan, Phil, and Les), but for the past few years, I’ve been researching and writing about ethics in the context of space settlement. So the perspective I brought to the panel was that of a “space person” encouraging other “space people” to think beyond the technical and financial challenges of space settlement and consider the ethical and social problems that we’ll also need to solve.”

Link’s background also allowed him to relate specific ethical and moral concerns that are also undeniable. When discussing the future of humanity in space and the “Great Migration,” historical parallels are often raised, both positive and negative. The very fact that some perceive past events like “westward expansion” and the colonizing of the Americas, forgetting the genocide, conquest, and slavery that was involved, raises the question of whether we are mature enough as a species to conduct similar experiments in space.

“I am not sure that humanity is ready for regular interplanetary travel and I don’t believe humanity is ready for interstellar travel. Technologically there are still a lot of questions about the safest, best, and most efficient ways to travel. And socially, culturally, spiritually, politically, and economically there are lots of unanswered and unresolved questions – in addition to there being several unaddressed historical problems that will linger with us if we do not confront some of the darker parts of collective histories. Humanity has a lot to work on before we are ready to travel amongst the stars.”


In summary, is humanity ready for interstellar travel? The answer is a hard no. Technologically, ethically, morally, psychologically, and spiritually, we are not prepared to take such a tremendous leap. But the fact that we are having the discussion demonstrates that we are determined to get there. A lot needs to be worked out in the meantime, and interplanetary exploration and settlement are an issue that must be dealt with first. The challenges of becoming “interplanetary” (and whether or not we should even try) will certainly test our mettle and the social fabric of our civilization.

In that respect, the coming decades and centuries will serve as a transitional time for our species. Long before crews ever travel beyond the Heliopause, robotic missions will be sent to explore nearby stars and their planets. As we draw nearer to the day when sending humans to other stars becomes practical, we will be better positioned to address the various questions and challenges. But we must start the discussion today, when the groundwork is being laid that could lead to an interplanetary and interstellar future.

The public outreach event was also an opportunity for Johnson to promote The Ross 248 Project, an anthology of original science fiction stories and scientific essays that explores how humans may one day settle on planets that orbit a red dwarf sun. The volume was edited by Les Johnson and engineer Ken Roy (inventor of the “Shell World” concept), who also contributed original stories. I had the honor of contributing to this volume as well in the form of a scientific essay that explores terraforming planets in red dwarf systems.

This latest anthology is the successor to Going Interstellar: Build Starships Now!, edited by Les Johnson and Jack McDevitt. Both volumes are published by Baen Books.

Further Reading: Interstellar Research Group

Matt Williams

Matt Williams is a space journalist and science communicator for Universe Today and Interesting Engineering. He's also a science fiction author, podcaster (Stories from Space), and Taekwon-Do instructor who lives on Vancouver Island with his wife and family.

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