Did you know that the average person is willing to sit in a car for up to 1 hour and 15 minutes before he or she becomes frustrated? That's what NASA's Moore says, explaining a concept called "mobility reach." Since an automobile averages 33 miles per hour, that will allow you to travel just over 40 miles before you hit that threshold. In a personal air vehicle, however, which NASA engineers estimate will travel four times faster, you'll travel more than 160 miles. That could mean a future when people live more than 100 miles away from their offices. It's called "on-demand aviation," allowing you to travel door-to-door, rather than gate-to-gate, says NASA's Moore, noting that another important facet of future transport vehicles will be the ability to give the user the same personal space we have come to expect from a car. The one-seater Puffin stands at rest vertically, sitting on its tail. When in flight, its user lies in the prone position. Its two propellers are powered by electric motors, which are 94 percent efficient (roughly three times more than conventional mechanical engines). The Puffin is just a small step on the road to an idealized personal aerial vehicle. The next iteration, known as the Samarai, is a two-seater about the size of an SUV with eight rotating blades that make it look like a food processor.
When we'll see something like Puffin: "I think the next 20 to 30 years are going to be incredibly exciting for aviation," says Moore, adding that soon flying will "map into people's daily lives."
Robert Pulliam, the inventor of Tubular Rail
, is fond of saying: "We're not changing fundamental technology; we're just reorganizing it." He's not kidding. In his new train concept, electrically motorized wheels are a "track," and the rails are notches on the train. Based on the principle of a cantilever beam — the same tenet that keeps Frank Lloyd Wright's Fallingwater from disappearing into a Pennsylvania waterfall — the train glides like a javelin through a series of rings that effectively hand the train from one to the other. According to Pulliam, for a train that's 400 feet long, the rings (each equipped with an electric motor that powers wheels that propel the train) need to be spaced 100 feet apart, so the train is always in contact with three rings and will stay perfectly level. The major cost benefit of Tubular Rail is that it obviates the need for tracks and the space requirements necessary to build them. Pulliam notes that cost for a mile-long Tubular Rail system would be one-quarter that of a comparable light-rail track and two-thirds that of high-speed rail. He sees applications for the trains, which he estimates can hit a speed of 150 mph, for either commuter purposes or as an alternative to high-speed rail. A team of engineering graduate students at Dartmouth's Thayer School of Engineering has already vetted his designs, looking for a fatal flaw (which it didn't find). "Our design would be priced as a much lower-cost system, and the frosting on the cake was that it was easy to install, it didn't take up a lot of land, and it was safer — in that the train was separated from cars and trucks."
When we'll see something like Tubular Rail: Texas A&M donated Tubular Rail a parcel of land in east Texas to build a two-mile system. The company needs $30 million to build that proof of principle.
We can thank the late Arthur C. Clarke for planting this idea in people's heads. As it turns out, there's some technical merit to it. Imagine the string that connects a tetherball to its pole. If the pole is rotating at a constant speed, the ball will essentially orbit it, and the string will be pulled taut. That's the theory behind the space elevator. A cable made constantly taut by the Earth’s rotation could connect an orbiting satellite to a launchpad in one of the Earth's oceans. A 13-ton payload of people or equipment could then use that cable to make the one-week journey into space. The ribbon would be made of carbon nanotubes, an electricity-conducting material that is stronger than steel. The process of making a cable out of these building blocks, which could accommodate an elevator, is still science fiction, but research into nanotubes is progressing at breakneck speed. The elevator could be powered with a laser shot from the surface at photovoltaic cells below the car, which would create electricity to power the device until the vessel leaves Earth's gravitational pull. (A counterweight could also be used to help the climber up the cable.) Physicist Bradley Edwards told the PBS program NOVA scienceNOW that a space elevator could reduce the cost of putting a payload into low Earth orbit to one-thousandth of what a rocket-based system would cost.
When we'll see a space elevator: While the physics make a space elevator a possibility, according to a recent CNN article, a contest held every year in Mojave Desert has yet to produce a winning prototype that can climb a one-kilometer cable. Regardless, a Washington State-based space elevator company called the LiftPort Group expects the first launch of its first model to take place in 2031.
A version of this story originally appeared on GOOD. Read it here.
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