Serial entrepreneur Elon Musk is at it again. Having already revolutionized electric cars and space exploration, the 42-year-old Musk unveiled on Monday his latest flight of fancy: a super-fast train that would whisk passengers from Los Angeles to San Francisco in a ridiculous 30 minutes.
Rocketing riders at 760 miles per hour, the train system, known as the Hyperloop, would use low-pressure tubes in which pod-like transporters jet forward at high speeds atop an air cushion. Musk has described the system as a cross between an air hockey table, a rail gun, and a Concorde. As if that wasn't enough, Musk also claims that it would be cheap to build. With a price tag of $6 to $10 billion, the Hyperloop would cost a fraction of California's current high-speed rail project, which aims to connect Sacramento to San Diego by 2026 and would leave the state with an estimated $68 billion bill.
If it all sounds too good to be true, that's probably because it is. Musk says that he doesn't plan to actually build the railway, and that he's releasing his design as an open-source tool. The Hyperloop now joins a storied history of pie-in-the-sky transportation projects, all of which at one point or another promised to revolutionize transportation. With an active imagination, some engineering talent, and a bloated ego, the impossible becomes a tantalizing possibility. Sometimes these projects come to fruition; other times they don't.
Meet Hyperloop's most famous predecessors.
The Space Elevator
First theorized in 1895 by the Russian rocket scientist Konstantin Tsiolkovsky, the concept behind a space elevator is an old one. By tethering a cable to the earth's surface and attaching it to a counterweight in space, a space elevator would in theory serve as a highly efficient way of sending men and materiel into space. No more dirty, expensive rockets would be required, and space would suddenly become accessible to human beings.
By solving the energy-intensive problem of escaping the earth's atmosphere and gravitational pull, an elevator into space has the potential to revolutionize space travel and create bases from which a new era of space exploration could be launched. To get a sense of the proportions and implications of such a structure, just have a look at the image below -- a sketch by Mondolithic Studios' Kenn Brown of a potential elevator:
But the engineering challenges inherent in such a structure make a space elevator a distant possibility. For starters, it would require a cable of some 22,000 miles with sufficient tensile strength to carry enormous loads over huge distances. So far, such cables do not exist. Carbon nanotubes are thought to represent the most promising material with which to fashion such a cable. But no one knows how to make long strands of carbon nanotubes. Until then, the idea of a space elevator remains off the table.
If you want to know more about the engineering challenges of constructing a space elevator, iO9 has a handy breakdown here.
The Moon Elevator
Though an elevator linking earth and space remains a tech geek's dream, a moon elevator might actually be possible to construct. And a company called LiftPort has taken to Kickstarter to try to make it a reality. LiftPort argues that the construction of a two-kilometer-long moon elevator stretching from the lunar surface to space will facilitate cheaper transportation to the moon and allow for moon-destined cargo to make a soft landing on its surface. The entire project aims to make the moon more accessible, and LiftPort's backers claim that the engineering challenges of such a structure are manifestly surmountable. A shorter cable and smaller gravitational pulls mean currently available technologies could be used in its construction. And the structure could potentially enable up to three dozen people to visit the moon every year. LiftPort has its eyes on eventually constructing a space elevator from earth, but for now they're focused on the more modest goal of the moon elevator. "Before we can build Earth's Elevator, we'll need to build one on the Moon," Michael Laine, the company's president, writes on their Kickstarter. "It is significantly easier, and much much cheaper. Importantly - we can build it with current technology - in about eight years."
To get a sense of how that system might work, check out this video:
The dream of sitting back on the highway and letting your car do the driving for you is one that has existed as long as automobiles have been widely available to middle-class consumers. Just have a look at this dreamscape from 1974:
Drinks on the highway may be a long way off, but self-driving cars most certainly are not. Google's self-driving automobiles have made remarkable strides in recent years, and they are now being tested on California streets and highways. By all accounts, Google's retrofitted fleet of Priuses and Lexus SUVs work remarkably well, but the Silicon Valley firm isn't the only company getting in on the action. Audi and Lexus are also developing the technology to create autopiloted cars, and a cheaper version of a self-driving system may be available within the next three years.
One step up on the dream scale, flying cars have populated the imaginations of science fiction writers for generations. If the image of an open highway and a full tank of gas represents the embodiment of freedom, flying cars are something else entirely, offering the tantalizing possibility of mastering the road and the sky. Consider, for example, how artist Syd Mead imagines one of these cars might look as it refuels:
Though a far cry from their sci-fi equivalent, flying cars are now surprisingly close to becoming a reality. Terrafugia, a Massachusetts-based company, plans to deliver its first batch of flying cars by 2015. It's not a particularly beautiful machine, but the company claims the cars can do about 450 miles at 115 miles per hour -- all on unleaded gas. Like the Marine Corps' much-maligned Osprey, Terrafugia's flying cars use a tilt-rotor system for vertical takeoff, and the design isn't particularly futuristic. Check out the video below of Terrafugia's latest project and consider whether you'd even want one of those things in your driveway.
Levitating Public Transport
Even if today's flying cars leave something to be desired, urban planners in Tel Aviv have a decidedly futurist vision for how to create a public transport system for their city. Officials have hired a U.S. design firm to implement a system devised by NASA and a company called skyTran that would utilize magnetically levitating pods as a public transportation system. The system would replace cars by suspending these pods along an elevated railway, with the pods providing point-to-point transportation. If it's difficult to picture this, have a look at the video below:
In theory, travelers could call up these pods using their cell phones. Stations, like the one pictured below, would provide convenient access to the pods, which are geared toward helping cut down traffic. Because the pods are powered using a magnetic levitation system, the ride should in theory be smooth and energy efficient. Whether the plan ever comes to fruition is an entirely different question.