Buzz
At present, the concept of interstellar travel and colonization seems highly improbable. Fundamental laws of physics indicate it’s likely impossible, and for many, this suggests it will never happen. However, those who think this way are not particularly adventurous. There are others who remain more optimistic, searching for ways to bend the laws of physics (or discover a loophole) that could make interstellar journeys and the exploration of new worlds possible.
10. Alcubierre Warp Drive
While the term 'warp drive' may seem more suited to the realm of Star Trek than NASA, the Alcubierre Warp Drive is actually a concept being considered as a potential answer—or at least the starting point—to overcoming the limitations of the universe when it comes to faster-than-light travel.
The core idea behind the Alcubierre Drive is relatively simple, and NASA uses the analogy of a moving walkway to explain it. Just as a person can walk only so fast on a moving walkway, the combined speed of the person and walkway allows them to reach their destination faster than they could walking on their own. Similarly, the warp drive moves through space-time within a bubble of expansion. Space-time contracts in front of the warp drive and expands behind it, which in theory could allow the drive to move faster than the speed of light. One of the key concepts here—expanding space-time—was already seen in the rapid expansion of the universe right after the Big Bang, suggesting that this idea might actually be viable in practice.
A more challenging aspect is the creation of the warp drive itself, which NASA states would necessitate a vast pocket of negative energy around the spacecraft. They’re uncertain whether such a thing is even possible. (Their final verdict on the matter was a definitive, 'I don’t know... maybe?') Additionally, manipulating space-time raises even more complex issues, such as time travel, powering the negative energy bubble, and controlling its activation and deactivation.
The concept originated from physicist Miguel Alcubierre, who likened the warp drive’s function to skipping across waves in space-time rather than traveling the conventional, slower route. Technically, it wouldn’t violate the laws of faster-than-light travel, and Alcubierre has even done the necessary calculations to support this theory.
9. The Interstellar Internet
It’s frustrating enough when you're lost on Earth and can't get Google Maps to load on your phone. Interstellar travel would present even more significant communication challenges. Reaching deep space is just the beginning—scientists are investigating how our manned and unmanned probes will communicate with Earth during their journeys.
In 2008, NASA completed the first successful tests of an interstellar version of the Internet. This project, which began in 1998 as a collaboration between NASA’s Jet Propulsion Laboratory (JPL) and Google, resulted in the development of the Disruption-Tolerant Networking (DTN) system. By 2008, they were able to send images to a spacecraft located 20 million miles away.
The technology required to manage long delays and disruptions in transmissions needs to ensure continued transmission even when the signal is cut off for up to 20 minutes. It’s capable of overcoming obstacles like solar flares, solar storms, and even planets that interfere with the signal, all while ensuring no data is lost during the transmission.
Vint Cerf, one of the creators of the Earthbound Internet and a key figure behind the concept of an interstellar one, explains that the DTN system resolves all the issues encountered by the traditional TCP/IP protocol when dealing with the vast distances of interplanetary travel. With TCP/IP, performing a Google search on Mars would take so long that the results would be outdated by the time they arrived, and the information would probably be a jumble of corrupted packets. However, with DTN, there’s an added feature—the ability to assign unique domain names to different planets and select which planet to route your Internet traffic through.
What about going beyond the planets we already know? Scientific American suggests there may be a way, albeit an extremely expensive and time-consuming one, to build an Internet that spans all the way to Alpha Centauri. By launching a fleet of self-replicating von Neumann probes (more on that later), a series of relay stations could be established, allowing signals to travel across what would essentially be an interstellar chain letter. The signal, optimized within our own system, would bounce between the probes, eventually making its way back to Earth or, depending on the direction, to Alpha Centauri. Naturally, this would require a large number of probes, each costing billions to construct and launch. However, given that the farthest probes would take thousands of years to reach their destination, we’d have time to gather funds and, likely, refine the technology, reducing the cost over time.
8. Embryo Space Colonization
One of the major obstacles in interstellar travel and colonization is the enormous amount of time it would take to reach any destination, even with advanced technologies like proposed warp drives. The challenge of transporting a group of settlers introduces a whole new set of problems. One proposed solution is to send not fully crewed ships but rather seed ships carrying frozen embryos. Once the ship nears its destination, the embryos would be thawed and grown. Eventually, these embryos would become children raised aboard the ship, and when the ship arrives, they would be ready to start a new civilization.
Naturally, this plan brings its own set of challenges, such as who—or what—will raise these children. Robots could be used for child-rearing, raising fascinating questions about what humans raised entirely by robots might be like. Could robots understand the needs of a growing child? Could they grasp the concepts of rewards, punishment, and human emotions? Additionally, the concept assumes that we will figure out how to preserve frozen embryos without damage for centuries and how to grow them in artificial environments. However, we have successfully managed this with sharks, so we might not be as far off as it seems.
A potential solution to bypass the robot nanny issue is to combine a seed ship with a sleeper ship. In this scenario, adults would be placed in suspended animation and awakened only when needed to help raise the children born aboard the seed ship. This cycle of child-rearing followed by hibernation could, in theory, create a stable population. A carefully selected batch of embryos would provide enough genetic diversity to sustain the population once the colony is established. An additional batch of embryos would also be included on the seed ship to impregnate the first generation of women, further diversifying the gene pool.
7. Self-Replicating Spacecraft
Anything we build and send into space faces challenges, and creating objects that must survive for millions of miles without breaking down or burning out seems like an insurmountable problem. However, the solution may have been proposed decades ago. In the 1940s, physicist John von Neumann introduced the idea of a self-replicating mechanical technology. While von Neumann didn’t apply this concept to interstellar travel, subsequent researchers began to see its potential for space exploration. The resulting von Neumann probes could, in theory, be used to explore vast, interstellar spaces. Some researchers even argue that the idea of being the first to think of this concept is not only arrogant but also highly unlikely.
Researchers from the University of Edinburgh published a study in the International Journal of Astrobiology that doesn’t focus on how we could use emerging technologies for our own exploration, but instead explores the possibility that someone else may have already been using them. Building upon earlier calculations that estimated how far different types of spacecraft could travel, they applied the equation to self-replicating craft and probes to see how the results might differ.
Their calculations were based on the idea of self-replicating probes that could utilize space debris and other materials to build what they termed child probes. These parent and child probes would eventually multiply to the point where they could cover the entire galaxy in roughly 10 million years—assuming they were only traveling at 10 percent of the speed of light. This leads to a striking conclusion: it’s highly likely that at some point, we’ve already been visited by self-replicating probes. Since we haven’t, they offer two possible explanations: either we’re not technologically advanced enough to recognize them, or we truly are isolated in the galaxy.
6. Black Hole Slingshots
The concept of using the gravitational pull of a planet or moon to slingshot a spacecraft has been successfully employed within our solar system, most famously by Voyager 2, which gained extra speed by passing Saturn and Uranus on its way out of the system. The idea revolves around navigating a spacecraft through a planet’s gravitational field to either accelerate or decelerate its velocity. This idea has also been a popular topic in science fiction works.
Physicist Kip Thorne proposed a similar concept to address one of the major challenges of interstellar travel—fuel consumption. However, Thorne suggested an even more daring approach: using binary black holes for a slingshot maneuver. By orbiting between two black holes, a spacecraft could gradually increase its speed with minimal fuel expenditure. After several circuits, the spacecraft’s velocity would approach the speed of light. At that point, the only thing left to do would be to accurately aim and fire a rocket thrust at the right moment to send it on its way across the stars.
Is this concept improbable? Undoubtedly. Is it fascinating? Absolutely. Thorne emphasizes that his idea has numerous challenges, such as the need for incredibly precise calculations and perfect timing to avoid accidentally flying through a star, planet, or any other inconvenient interstellar body. Other issues, such as how to slow down, stop, and eventually return home, also pose significant challenges. But if you’re willing to undertake such a venture in the first place, it’s likely you wouldn’t be overly concerned about getting home again.
There’s already a real-world example that hints at the feasibility of this idea. In 2000, astronomers observed 13 supernovae traveling at a staggering 5 million miles per hour through the galaxy. Researchers from the University of Illinois at Urbana-Champaign determined that these rogue stars were ejected from their galaxy by a pair of black holes locked in an orbit after the destruction and merger of two galaxies.
5. Starseed Launcher
When it comes to launching even self-replicating probes, the challenge of fuel consumption remains a major obstacle. However, that hasn’t deterred innovators from coming up with new methods to launch probes across interstellar distances, a process that, with current technology, would demand vast amounts of energy—potentially in the megaton range.
Forrest Bishop, from the Institute of Atomic-Scale Engineering, claimed to have developed a technique for launching interstellar probes that requires only energy roughly equivalent to a car battery. The proposed Starseed Launcher would stretch around 1,000 kilometers (600 miles) in length and consist mostly of wire. Despite its vast length, it could be stored on a shuttle and powered by a simple 10-volt battery.
A key component of the plan involves launching probes that weigh just micrograms, carrying the basic data necessary to construct additional probes in space. These probes, which could number in the billions, would be launched from multiple devices. Bishop explained that his system is simpler because the self-replicating probes could merge after being launched. While the launchers would rely on superconducting magnetic levitation coils to generate the needed opposing force, Bishop acknowledged that certain issues, such as how the probes would survive hazards like interstellar radiation and debris, need to be worked out before the system could be implemented practically.
4. Engineering Plants to Thrive in Space
Once we’ve reached our destination (or even just begun the journey), a reliable method will be necessary for growing food and generating oxygen. Physicist Freeman Dyson has proposed some intriguing solutions for how this could be achieved.
In 1972, Dyson delivered his famous lecture at Birkbeck College in London, where he proposed that with some genetic engineering, trees could be created that would not only survive but thrive on environments as extreme as a comet's surface. By altering the tree to reflect ultraviolet light and become more efficient in water retention, these trees could take root and grow to sizes unimaginable on Earth. He even speculated about the possibility of black trees in the future, both on Earth and in space. Silicon-based trees and leaves, he argued, would be far more efficient, and efficiency is key to long-term survival. Dyson emphasized that this wouldn't be an overnight breakthrough and would likely take well into the next two centuries to develop the necessary technology and expertise to manipulate plants in such a way.
Dyson’s concept may not be as outlandish as it seems. NASA's Institute for Advanced Concepts is focused on solving futuristic problems, including developing plants that could survive on Mars. Even plants grown in controlled environments on Mars would face extreme conditions, and researchers are experimenting with combining plants and extremophiles—microscopic organisms that thrive in Earth’s most hostile environments. From UV-resistant tomato plants at high altitudes to bacteria that survive in the planet’s most extreme cold, heat, and pressure, we may already have the fundamental components to create Martian gardens. We just need to figure out how to put them all together.
3. Project Longshot
Project Longshot was a plan, perhaps fittingly named with a touch of cynicism, developed in the late 1980s by a collaboration between the US Naval Academy and NASA. The mission’s primary objective was to launch an unmanned probe aimed at Alpha Centauri around the turn of the 21st century. The journey would take about 100 years to complete. However, before it could even be launched, critical technological developments had to be made for the mission to become a reality.
To make this ambitious probe work, a range of technologies had to align: communications lasers, a long-lasting fission reactor, and a fusion microexplosion drive. The probe was designed to operate autonomously since communication over vast interstellar distances would be too slow for timely data transmission. The system had to be extremely resilient, considering it would take around 100 years to reach its target destination.
Longshot’s mission was to travel to Alpha Centauri with a variety of objectives, the most significant of which was gathering astronomical data to precisely measure the distances to billions, if not trillions, of stars. Powered by its nuclear reactor until it shut down, Longshot was a bold undertaking that, unfortunately, never got off the ground.
Nevertheless, the concept is far from forgotten. In 2013, Project Longshot II began to take shape through a student project led by Icarus Interstellar. Thanks to decades of technological progress, the new version can benefit from these advances. Enhancements to the project include halving the expected flight time, reassessing fuel consumption, and possibly redesigning Longshot entirely.
The final version of the project offers a fascinating insight into how challenges evolve with the integration of new technology and insights. While the laws of physics remain unchanged, the potential for Longshot has transformed over 25 years, presenting a promising vision for the future of interstellar travel.
2. 2suit
Reproducing in space presents several challenges, particularly in zero-gravity environments. In 2009, Japanese experiments with mouse embryos demonstrated that while zero gravity doesn’t hinder fertilization, embryos growing outside Earth’s gravitational pull (or an equivalent force) face abnormal development. Problems arise during cell division and specialization. However, it’s not impossible; some embryos grown in space were successfully implanted into female mice and were born normally.
This raises another intriguing question: How does procreation function in a zero-gravity environment? The laws of physics, especially the principle that every action has an equal and opposite reaction, make the mechanics of this process quite complicated. Still, writer, actress, and inventor Vanna Bonta has given it considerable thought.
The result of Bonta’s thinking is the 2suit, a space suit designed to accommodate two people zipped inside of it to facilitate the creation of space babies. In fact, the suit has been tested. In 2008, it was used on the aptly (though unromantically) named Vomit Comet. While Bonta envisions space honeymoons becoming a reality thanks to her invention, she also notes its other practical uses, such as conserving body heat in emergencies.
1. In-Situ Resource Utilization
While living off the land may be a trendy concept on Earth, it will be a necessity for extended space missions. NASA is investigating In-Situ Resource Utilization (ISRU), a strategy for using materials found in space and on other planets. Space missions have limited resources, and creating systems to harness local materials will be vital for long-term colonization or exploration, especially in locations where resupply missions are not feasible. Initial ISRU experiments took place on the slopes of Hawaii’s volcanoes and in lunar mission simulations, focusing on extracting things like fuel components from natural terrain such as ash.
In August 2014, NASA made a groundbreaking announcement regarding the new technology that would be featured on the upcoming Mars rover, scheduled for launch in 2020. Among the tools is MOXIE, the Mars Oxygen In-Situ Resources Utilization Experiment. As its name suggests, MOXIE is designed to extract oxygen from the thin Martian atmosphere, which is composed of roughly 96 percent carbon dioxide, converting it into oxygen and carbon monoxide. It is expected to produce approximately 22 grams of oxygen every hour of operation. NASA also hopes that MOXIE will prove its ability to operate continuously without any drop in productivity or efficiency. Not only is MOXIE seen as a pivotal development for long-term space exploration, but it could also pave the way for future devices capable of isolating different gases and other resources.
