Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and Space Radio, and author of "Your Place in the Universe." Sutter contributed this article to Space.com's Expert Voices: Op-Ed & Insights.
Interstellar space travel. Fantasy of every five-year-old kid within us. Staple of science fiction serials. Boldly going where nobody has gone before in a really fantastic way. As we grow ever more advanced with our rockets and space probes, the question arises: could we ever hope to colonize the stars? Or, barring that far-flung dream, can we at least send space probes to alien planets, letting them tell us what they see?
The truth is that interstellar travel and exploration is technically possible. There's no law of physics that outright forbids it. But that doesn't necessarily make it easy, and it certainly doesn't mean we'll achieve it in our lifetimes, let alone this century. Interstellar space travel is a real pain in the neck.
Related: Gallery: Visions of Interstellar Starship Travel
If you're sufficiently patient, then we've already achieved interstellar exploration status. We have several spacecraft on escape trajectories, meaning they're leaving the solar system and they are never coming back. NASA's Pioneer missions, the Voyager missions, and most recently New Horizons have all started their long outward journeys. The Voyagers especially are now considered outside the solar system, as defined as the region where the solar wind emanating from the sun gives way to general galactic background particles and dust.
So, great; we have interstellar space probes currently in operation. Except the problem is that they're going nowhere really fast. Each one of these intrepid interstellar explorers is traveling at tens of thousands of miles per hour, which sounds pretty fast. They're not headed in the direction of any particular star, because their missions were designed to explore planets inside the solar system. But if any of these spacecraft were headed to our nearest neighbor, Proxima Centauri, just barely 4 light-years away, they would reach it in about 80,000 years.
I don't know about you, but I don't think NASA budgets for those kinds of timelines. Also, by the time these probes reach anywhere halfway interesting, their nuclear batteries will be long dead, and just be useless hunks of metal hurtling through the void. Which is a sort of success, if you think about it: It's not like our ancestors were able to accomplish such feats as tossing random junk between the stars, but it's probably also not exactly what you imagined interstellar space travel to be like.
Related: Superfast Spacecraft Propulsion Concepts (Images)
To make interstellar spaceflight more reasonable, a probe has to go really fast. On the order of at least one-tenth the speed of light. At that speed, spacecraft could reach Proxima Centauri in a handful of decades, and send back pictures a few years later, well within a human lifetime. Is it really so unreasonable to ask that the same person who starts the mission gets to finish it?
Going these speeds requires a tremendous amount of energy. One option is to contain that energy onboard the spacecraft as fuel. But if that's the case, the extra fuel adds mass, which makes it even harder to propel it up to those speeds. There are designs and sketches for nuclear-powered spacecraft that try to accomplish just this, but unless we want to start building thousands upon thousands of nuclear bombs just to put inside a rocket, we need to come up with other ideas.
Perhaps one of the most promising ideas is to keep the energy source of the spacecraft fixed and somehow transport that energy to the spacecraft as it travels. One way to do this is with lasers. Radiation is good at transporting energy from one place to another, especially over the vast distances of space. The spacecraft can then capture this energy and propel itself forward.
This is the basic idea behind the Breakthrough Starshot project, which aims to design a spacecraft capable of reaching the nearest stars in a matter of decades. In the simplest outline of this project, a giant laser on the order of 100 gigawatts shoots at an Earth-orbiting spacecraft. That spacecraft has a large solar sail that is incredibly reflective. The laser bounces off of that sail, giving momentum to the spacecraft. The thing is, a 100-gigawatt laser only has the force of a heavy backpack. You didn't read that incorrectly. If we were to shoot this laser at the spacecraft for about 10 minutes, in order to reach one-tenth the speed of light, the spacecraft can weigh no more than a gram.
That's the mass of a paper clip.
Related: Breakthrough Starshot in Pictures: Laser-Sailing Nanocraft to Study Alien Planets
This is where the rubber meets the interstellar road when it comes to making spacecraft travel the required speeds. The laser itself, at 100 gigawatts, is more powerful than any laser we've ever designed by many orders of magnitude. To give you a sense of scale, 100 gigawatts is the entire capacity of every single nuclear power plant operating in the United States combined.
And the spacecraft, which has to have a mass no more than a paper clip, must include a camera, computer, power source, circuitry, a shell, an antenna for communicating back home and the entire lightsail itself.
That lightsail must be almost perfectly reflective. If it absorbs even a tiny fraction of that incoming laser radiation it will convert that energy to heat instead of momentum. At 100 gigawatts, that means straight-up melting, which is generally considered not good for spacecraft.
Once accelerated to one-tenth the speed of light, the real journey begins. For 40 years, this little spacecraft will have to withstand the trials and travails of interstellar space. It will be impacted by dust grains at that enormous velocity. And while the dust is very tiny, at those speeds motes can do incredible damage. Cosmic rays, which are high-energy particles emitted by everything from the sun to distant supernova, can mess with the delicate circuitry inside. The spacecraft will be bombarded by these cosmic rays non-stop as soon as the journey begins.
Is Breakthrough Starshot possible? In principle, yes. Like I said above, there's no law of physics that prevents any of this from becoming reality. But that doesn't make it easy or even probable or plausible or even feasible using our current levels of technology (or reasonable projections into the near future of our technology). Can we really make a spacecraft that small and light? Can we really make a laser that powerful? Can a mission like this actually survive the challenges of deep space?
The answer isn't yes or no. The real question is this: are we willing to spend enough money to find out if it's possible?
Learn more by listening to the episode "Is interstellar travel possible?" on the Ask A Spaceman podcast, available on iTunes and on the Web at http://www.askaspaceman.com. Thanks to @infirmus, Amber D., neo, and Alex V. for the questions that led to this piece! Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.
Follow us on Twitter @Spacedotcom or Facebook.
Originally posted here:
- Space travel is giving the future of cryptocurrency a boost for one surprising reason - Express.co.uk - June 30th, 2020
- How will private space travel change the way we explore the Solar System? - BBC Focus Magazine - June 30th, 2020
- 5 Public Space Companies to Invest in Over the Next Decade - seattlepi.com - June 30th, 2020
- New Houston-made satellites to mimic versatility of the chameleon in space - Houston Chronicle - June 30th, 2020
- Relativity and 6K Partner to Develop AM Rocket Parts for Space Made from Sustainable Materials - PR Newswire UK - June 30th, 2020
- SpaceX news: EU to boost their space exploration to keep up with China and US - Express.co.uk - June 30th, 2020
- Virgin Galactic aims to evolve $15 billion business from space tourism - Business Insider - June 30th, 2020
- Resolution approved to urge feds to locate Space Command headquarters in Ohio - MahoningMatters.com - June 30th, 2020
- At Least 110 People Needed to Start Life on Mars, Space Expert Says - Yahoo News - June 30th, 2020
- Why go 'horse and buggy' to Mars when we could go supersonic? | TheHill - The Hill - June 30th, 2020
- Recapping the Historic First Half of 2020 - Morning Brew - June 30th, 2020
- SpaceX gearing up for another launch of Starlink broadband satellites this week - Spaceflight Now - June 30th, 2020
- Boeing tests Starliner parachutes ahead of second test flight - Digital Trends - June 30th, 2020
- 5 Best Films About Space Exploration (& 5 The Worst), Ranked According To IMDb - Screen Rant - June 30th, 2020
- First UK night out of lockdown camping in Northern Ireland - The Guardian - June 30th, 2020
- The story of Ed Dwight: the man who nearly became the first African-American to reach space - The Next Web - June 30th, 2020
- Senate approves resolution urging feds to locate Space Command headquarters in Ohio - The Center Square - June 30th, 2020
- New company Space Perspective wants to take you to the stratosphere via high-altitude balloon - The Verge - June 21st, 2020
- spaceship neptune is a balloon that will take you to the edge of space - Designboom - June 21st, 2020
- The end of food? 'Taste synthesizer' will transform space travel, dieting and sex - Daily Star - June 21st, 2020
- SpaceX to build floating space ports for rockets destined for the Moon and Mars, and for hypersonic travel to Earth - Up News Info - June 21st, 2020
- What's the science on the Emirates Mars Mission? - DW (English) - June 21st, 2020
- STREAMING WARS: Netflixs big-budget comedy Space Force has all the right ingredients, but fails to deliver the laughs - SaltWire Network - June 21st, 2020
- Coronavirus: Travel to Spain, and the 'second wave' - BBC News - June 21st, 2020
- Is this double-decker seat the future of airplane travel? - CNN - June 21st, 2020
- Safe vacations and traveling during coronavirus: Advice to follow - TODAY - June 21st, 2020
- The Internets Most Censored Space - The New York Times - June 21st, 2020
- Virgin Galactic Stock Is Only for Astronauts and Speculators - InvestorPlace - June 21st, 2020
- Best Solar Eclipse Photos And YouTube Videos Of The Solstice Ring Of Fire From Around The World - Forbes - June 21st, 2020
- The amazon bond offering - Nairametrics - June 21st, 2020
- Satellites, outer space travel to be open for private companies in India: Govt - Livemint - June 13th, 2020
- Former astronaut becomes first person to visit both space and the deepest place in the ocean - CNN - June 13th, 2020
- Guest View: Despite space flight, there is no Planet B - The Register-Guard - June 13th, 2020
- Ask Ethan: How Does The Fabric Of Spacetime Expand Faster Than The Speed Of Light? - Forbes - June 13th, 2020
- Poem of the week: Sermon (for the Burial of Cassini) by Ella Frears - Telegraph.co.uk - June 13th, 2020
- Impact of COVID-19 on Space Tourism Market to Garner Astounding CAGR of 16.6% by 2025 Including Top Key Players- Space Adventures, EADS Astrium,... - June 13th, 2020
- Letters to the Editor: June 12, 2020 - West Hawaii Today - June 13th, 2020
- Have Scientists Found a Hybernation 'Button' for Humans? - The National Interest - June 13th, 2020
- Is It Risky To Ride In A Convertible? Go To A Casino? Travel With Kids? : Goats and Soda - NPR - June 13th, 2020
- Astronomer on why he is a 'frustrated martian', his love of the night sky and what the future holds for space travel - Times & Star - June 13th, 2020
- From Breakfast at Tiffanys to To Kill A Mockingbird, the best and worst examples of diversity in film - Evening Standard - June 13th, 2020
- What Space Travel Will Look Like in the Future - Earthly ... - June 9th, 2020
- WRITE TEAM: Space travel is back to once again give us faraway dreams - MyWebTimes.com - June 9th, 2020
- Former NASA astronaut Kathy Sullivan becomes first person to travel to space and ocean's deepest point - ABC News - June 9th, 2020
- Netflixs Space Force Just Exposed Animal Cruelty In Space Travel - LIVEKINDLY - June 9th, 2020
- You Can Now Tour the International Space Station From the Comfort of Your Home - Robb Report - June 9th, 2020
- This is the 'most ridiculously overvalued' trade in the travel space, strategist warns - CNBC - June 9th, 2020
- Evolution of 3rd, 4th and 5th Dimensions of Travel - Use Cases, Infrastructure Required, Application Areas, and Growth Opportunities -... - June 9th, 2020
- The Dangers of Space, Military Rivals and Other New Books to Read - Smithsonian.com - June 9th, 2020
- Here's how astronauts exercise in space without gravity - Yahoo Lifestyle - June 9th, 2020
- A group of enthusiasts has annotated the assembly code for the Apollo 11 mission to the Moon - Neowin - June 9th, 2020
- Faster-than-light travel: Is warp drive really possible? - BBC Focus Magazine - June 9th, 2020
- America Once Planned To Send An Apollo Spacecraft To A Soviet Space Station - Jalopnik - June 9th, 2020
- Trend report: nothing 'normal' about travel in the age of Covid-19 - Globetrender - June 9th, 2020
- Astronomer on why he is a 'frustrated martian', his love of the night sky and what the future holds for space travel - The Westmorland Gazette - June 9th, 2020
- Future Meeting Space explores customer needs and expectations on new event formats - Travel Daily News International - June 9th, 2020
- News: New Rotherham active travel projects - Rotherham Business News - June 9th, 2020
- Spain to extend restrictions on international travelers until June 15 - EL PAS in English - May 15th, 2020
- The 100 Series Finale Trailer Teases Screams, Space Travel, And Drastic Haircuts - Gizmodo Australia - May 15th, 2020
- On the Road Review: Ram 2500 Limited Crew Cab Diesel - Press Herald - May 15th, 2020
- Spains reeling tourism industry objects to travel restrictions - EL PAS in English - May 15th, 2020
- Virgin Galactic Is Grounded with No Profit and Little Revenue - InvestorPlace - May 15th, 2020
- Astronaut on how to survive isolation, and the future of space travel - Business Insider - Business Insider - May 14th, 2020
- Virgin Galactic Is a Solid Long-Term Bet on Space Travel Demand - InvestorPlace - May 14th, 2020
- Meet The Women Of The San Diego Art Prize - KPBS - May 14th, 2020
- Visual Artist Melissa Walter Makes Sense Of The Stars - KPBS - May 14th, 2020
- Astronauts experimented with Nickelodeon's slime in space - CNN - May 14th, 2020
- Virgin Group to sell shares of space venture to aid travel business - UPI News - May 14th, 2020
- What to binge next: 10 sci-fi shows to escape into the future - UPI.com - May 14th, 2020
- The sky is full of weird X-shaped galaxies. Here's why. - Live Science - May 14th, 2020
- What is Jeff Bezos net worth? - The Scottish Sun - May 14th, 2020
- The 100 Series Finale Trailer Teases Screams, Space Travel, and Drastic Haircuts - Gizmodo - May 14th, 2020
- 11 Ways Space Travel Will Change in the Next Decade ... - May 4th, 2020
- The 12 Greatest Challenges for Space Exploration | WIRED - May 4th, 2020
- Interstellar travel - Wikipedia - May 4th, 2020
- NASA Astronaut Talks Surviving Isolation, Daily Life in Space, and Earth's Beauty - Esquire.com - May 4th, 2020
- Tom Cruise teaming with Elon Musk, NASA to shoot action movie in space - Yahoo News - May 4th, 2020
- Patty Crane: Book shows importance of the moon, Earth's iconic satellite - Joplin Globe - May 4th, 2020
- SpaceX to launch first crewed spacecraft to International Space Station | Forge - ForgeToday - May 4th, 2020
- Video: Astronaut teaches Dundee kids about space travel with virtual visits - Evening Telegraph - May 4th, 2020