interstellar travel Archives

January 23, 2023January 23, 2023 by Matt Williams

A Novel Propulsion System Would Hurl Hypervelocity Pellets at a Spacecraft to Speed it up

Graphic depiction of Pellet-Beam Propulsion for Breakthrough Space Exploration. Credits: Artur Davoyan

Today, multiple space agencies are investigating cutting-edge propulsion ideas that will allow for rapid transits to other bodies in the Solar System. These include NASA’s Nuclear-Thermal or Nuclear-Electric Propulsion (NTP/NEP) concepts that could enable transit times to Mars in 100 days (or even 45) and a nuclear-powered Chinese spacecraft that could explore Neptune and its largest moon, Triton. While these and other ideas could allow for interplanetary exploration, getting beyond the Solar System presents some major challenges.

As we explored in a previous article, it would take spacecraft using conventional propulsion anywhere from 19,000 to 81,000 years to reach even the nearest star, Proxima Centauri (4.25 light-years from Earth). To this end, engineers have been researching proposals for uncrewed spacecraft that rely on beams of directed energy (lasers) to accelerate light sails to a fraction of the speed of light. A new idea proposed by researchers from UCLA envisions a twist on the beam-sail idea: a pellet-beam concept that could accelerate a 1-ton spacecraft to the edge of the Solar System in less than 20 years.

December 25, 2022December 25, 2022 by Andy Tomaswick

Lightweight Picogram-Scale Probes Could be the Best way to Explore Other Star Systems

Inspiration for space exploration can come from all corners. One of the most inspiring, or terrifying, sources of inspiration for some in space exploration came from computer science expert John von Neumann, who laid out a framework for self-replicating machines in a series of lectures he gave in 1948. Ever since then, scientists and engineers have been debating the advantages, and the perils, of such a system.

However, while technology has indeed advanced a long way since the 1940s, it still seems like we are still a long way from having a fully functional von Neumann machine. That is unless you turn to biology. Even simple biological systems can perform absolutely mind-blowing feats of chemical synthesis. And there are few people in the world today who know that better than George Church. The geneticist from Harvard has been at the forefront of a revolution in the biological sciences over the last 30 years. Now, he’s published a new paper in Astrobiology musing about how biology could aid in creating a pico-scale system that could potentially explore other star systems at next to no cost.

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December 15, 2022December 27, 2022 by Matt Williams

Birds use Dynamic Soaring to Pick Up Velocity. We Could Use a Similar Trick to Go Interstellar

The Solar Sail demonstration mission. Credit: NASA

To stand on a coastal shore and watch how eagles, ravens, seagulls, and crows take flight in high winds. it’s an inspiring sight, to be sure. Additionally, it illustrates an important concept in aerial mechanics, like how the proper angling of wings can allow birds to exploit differences in wind speed to hover in mid-air. Similarly, birds can use these same differences in wind speed to gain bursts of velocity to soar and dive. These same lessons can be applied to space, where spacecraft could perform special maneuvers to pick up bursts of speed from “space weather” (solar wind).

This was the subject of a recent study led by researchers from McGill University in Montreal, Quebec. By circling between regions of the heliosphere with different wind speeds, they state, a spacecraft would be capable of “dynamic soaring” the same way avian species are. Such a spacecraft would not require propellant (which makes up the biggest mass fraction of conventional missions) and would need only a minimal power supply. Their proposal is one of many concepts for low-mass, low-cost missions that could become interplanetary (or interstellar) explorers.

December 28, 2021December 28, 2021 by Matt Williams

New Calculations Show That an Interstellar Bussard Ramjet Drive Would Need a Magnetic Field Stretching 150 Million Kilometres

An artist's impression of a ramjet drive. Credit: NASA

In the 1960s, American physicist Robert W. Bussard proposed a radical idea for interstellar travel: a spacecraft that relied on powerful magnetic fields to harvest hydrogen directly from the interstellar medium. The high speed of this “ramjet” forces the hydrogen into a progressively constricted magnetic field until fusion occurs. The magnetic field then directs the resulting energy towards the rear of the spacecraft to generate propulsion.

As it’s come to be known, the Bussard Ramjet has since been popularized by hard science fiction writers like Poul Anderson, Larry Niven, Vernor Vinge, and science communicators like Carl Sagan. Unfortunately, a team of physicists recently analyzed the concept in more detail and concluded that Bussard’s idea is not practical. At a time when interstellar travel looks destined to become a real possibility, this analysis might seem like a wet blanket but is more of a reality check.

August 11, 2021August 11, 2021 by Matt Williams

Avoiding the Great Filter. How Long Until We’re Living Across the Solar System?

If you’re a fan of the Search for Extraterrestrial Intelligence (SETI) and the Fermi Paradox, then it’s likely you’ve heard of a concept known as the Great Filter. In brief, it states that life in the Universe may be doomed to extinction, either as a result of cataclysmic events or due to circumstances of its own making (i.e., nuclear war, climate change, etc.) In recent years, it has been the subject of a lot of talk and speculation, and not just in academic circles.

Stephen Hawking and Elon Musk have also weighed in on the issue, claiming that humanity’s only chance at long-term survival is to become “interplanetary.” Addressing this very possibility, a research team led by NASA’s Jet Propulsion Laboratory (JPL) recently created a timeline for potential human expansion beyond Earth. According to their findings, we have the potential of going interplanetary by the end of the century and intragalactic by the end of the 24th!

June 10, 2021June 10, 2021 by Matt Williams

Sending a Spacecraft to Another Star Will Require a Million Lasers Working Together

An artist's illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. The leakage from such beams as they sweep across the sky would appear as Fast Radio Bursts (FRBs), similar to the new population of sources that was discovered recently at cosmological distances. Credit: M. Weiss/CfA

In 2016, Russian-American billionaire Yuri Milner founded Breakthrough Initiatives, a non-profit organization dedicated to investigating some of the most enduring mysteries of the Universe. Chief among their scientific efforts is Breakthrough Starshot, a proof-of-concept prototype that combines a lightsail, a nanocraft, and directed energy (aka. laser) propulsion to create a spacecraft capable of reaching the nearest star (Alpha Centauri) in our lifetimes.

Naturally, this presents all sorts of technical and engineering challenges, not the least of which is the amount of power needed to accelerate the spacecraft to relativistic speeds (a fraction of the speed of light). Luckily, scientists from the Australian National University (ANU) recently came up with a design for a directed-energy array made up of millions of individual lasers positioned across the Earth’s surface.

March 24, 2021March 24, 2021 by Brian Koberlein

Gravitational Lenses Could Allow a Galaxy-Wide Internet

An early NASA concept of an interstellar space probe. Credit: NASA/Johns Hopkins University Applied Physics Laboratory

As Carl Sagan once said, “The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars.” And our first emissaries to the stars will be robotic probes. These interstellar probes will be largely autonomous, but we will want to communicate with them. At the very least we will want them to phone home and tell us what they’ve discovered. The stars are distant, so the probes will need to make a very long-distance call.

December 20, 2020February 7, 2022 by Matt Williams

Beyond “Fermi’s Paradox” XIV: What is the Aurora Hypothesis?

Credit and Copyright: Stefan Payne-Wardenaar; Magellanic Clouds: Robert Gendler/ESO

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that the reason for the Great Silence is that colonizing other star systems is hazardous to our health!

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?“

This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Aurora Hypothesis that states that just because planets are habitable doesn’t mean that intelligent life can colonize there.

October 10, 2020November 30, 2020 by Matt Williams

Want the Fastest Solar Sail? Drop it Into the Sun First

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

In the coming decades, multiple space agencies plan to return astronauts to the Moon (or to send them there for the first time) and mount the first crewed missions to Mars. Between that and the explosive growth we are seeing in Low Earth Orbit (LEO), there is no doubt that we live in an era of renewed space exploration. It’s therefore understandable that old and new concepts for interstellar travel are also being considered these days.

Right now, a considerable focus is on light sails that generate their own propulsion by radiation pressure or are accelerated by lasers. These concepts present all kinds of technical and engineering challenges. Luckily, Coryn Bailer-Jones of the Max Planck Institute for Astronomy (MPIA) recently conducted a study where he argues for a “Sun Diver” light sail that will pick up all the speed it needs by diving close to the Sun.

September 23, 2020September 24, 2020 by Matt Williams

What’s the Best Way to Communicate With an Interstellar Probe When it’s Light-Years Away From Earth?

It’s no secret that humanity is poised to embark on a renewed era of space exploration. In addition to new frontiers in astronomical and cosmological research, crewed missions are also planned for the coming decades that will send astronauts back to the Moon and to Mars for the first time. Looking even further, there are also ideas for interstellar missions like Breakthrough Starshot and Project Dragonfly and NASA’s Starlight.

These mission concepts entail pairing a nanocraft with a lightsail, which would then accelerated by a directed-energy array (lasers) to achieve a fraction of the speed of light (aka. relativistic velocity). Naturally, this raises a number of technical and engineering challenges, not the least of which is communications. In a recent study, a team of scientists sought to address that very issue and considered various methods that might be used.