Why sub-orbital flights aren’t going to happen anytime soon

Virgin Galactic sub-orbital space plane

The hype over supersonic and sub-orbital flying has been going on for at least 30-40 years, the promise being that people will be able to go anywhere in the world in a matter of hours. The usual example being London-Sydney in a few hours.

But as Charlie Stross explains in this excellent article, hypersonic and sub-orbital travel will be prohibitively expensive however it is done.

Let’s start with a simple normative assumption; that sub-orbital spaceplanes are going to obey the laws of physics. One consequence of this is that the amount of energy it takes to get from A to B via hypersonic airliner is going to exceed the energy input it takes to cover the same distance using a subsonic jet, by quite a margin. Yes, we can save some fuel by travelling above the atmosphere and cutting air resistance, but it’s not a free lunch: you expend energy getting up to altitude and speed, and the fuel burn for going faster rises nonlinearly with speed. Concorde, flying trans-Atlantic at Mach 2.0, burned about the same amount of fuel as a Boeing 747 of similar vintage flying trans-Atlantic at Mach 0.85 … while carrying less than a quarter as many passengers.

Rockets aren’t a magic technology. Neither are hybrid hypersonic air-breathing gadgets like Reaction Engines’ Sabre engine. It’s going to be a wee bit expensive. But let’s suppose we can get the price down far enough that a seat in a Mach 5 to Mach 10 hypersonic or sub-orbital passenger aircraft is cost-competitive with a high-end first class seat on a subsonic jet. Surely the super-rich will all switch to hypersonic services in a shot, just as they used Concorde to commute between New York and London back before Airbus killed it off by cancelling support after the 30-year operational milestone?

Well, no.

Quite. How are you going to transport these (mega-rich) people from the hypersonic terminal somewhere far away from civilization to the city they want to travel to? And how are you going to intercept a hypersonic jet which has been commandeered by terrorists?

None of it makes economic or logistical sense.

Concorde, from Wikipedia

The biggest problem with Concorde was the sonic boom it generated, which meant that it could only travel across oceans supersonically, When it was over land, Concorde was sub-sonic and still managed to rattle windows below it because of the enormous noise it made.

Concorde was able to break the sound barrier during its flights and was therefore able to cause a sonic boom. Sonic booms were a problem in North Cornwall and North Devon as these areas were underneath the flight path of Concorde. Windows would rattle and in some cases the “torching” (pointing underneath roof slates) would be dislodged with the vibration. It was proposed that Concorde, before it was decommissioned, could open up new flight paths to Australia. However the plans were scrapped due to the fact that few other countries would allow Concorde to fly at supersonic speeds due to sonic booms being disruptive and potentially damaging.

But Charlie Stross’ article is an excellent counter-blast to the hype that we would ever want to travel sub-orbitally or hypersonically. It really is hard science fiction and we’ve been sold it since the space age.


Another flying car prototype from Aeromobil

For as long as there has been a car stuck in traffic, there has been a wish for the flying car. Most never get off the ground (literally as well as financially).

And they are all prototypes.

This one actually works. And its from a company called Aeromobil in Slovakia.


It’s 6 meters long, so not something that can be parked in a normal carpark. But it does fly.

My worry is that any sort of prang in traffic on the ground would be a total insurance writeoff. How would you unbend the tail section?

It is beautiful though…

The Real Hoverboard is the world’s most boring swing

Sometimes we get technology proposals from films, science-fiction films or even comedy science fiction films.

Take the hoverboard, the magical skateboard-without-wheels used by Marty McFly in “Back to the Future Part 2”. You could even cross water with it.

Image from the “Best of the 80s” blog

Young nerds of the 1980s must have thought: “that would be the coolest thing ever”. Of course it would.

But now in 2014, for only $10,000 each, you can now ride a hoverboard for yourself. It won’t cross water, of course, or even roads, sidewalks or shopping malls.

And you can’t do any tricks at all.

Watch the thrills!

It’s called the Hendo hoverboard, and it has its own Kickstarter page. It’s basically a load of strong magnets under a board which you can ride on a copper plate. And there’s a cool blue light there as well.

Call me cynical (and I am not most of the time), but what you have here is the world’s most boring pendulum exercise. As a child I used to imitate the same range of motion by standing on the swing on my family’s swingset. But other than seeing how far I could swing before launching myself onto the lawn, it wasn’t that exciting.

But it was more exciting that the Hendo hoverboard and cost a lot less.

I think that’s its proved that skateboards with wheels are far more interesting than any hoverboard, if only for the danger of breaking several bones trying to do the most ridiculous tricks.

The self-driving car is an accident waiting to happen

A fascinating article from Slate on Google’s self-driving car technology and what are really the limits of artificial intelligence.

A good technology demonstration so wows you with what the product can do that you might forget to ask about what it can’t. Case in point: Google’s self-driving car. There is a surprisingly long list of the things the car can’t do, like avoid potholes or operate in heavy rain or snow. Yet a consensus has emerged among many technologists, policymakers, and journalists that Google has essentially solved—or is on the verge of solving—all of the major issues involved with robotic driving. The Economist believes that “the technology seems likely to be ready before all the questions of regulation and liability have been sorted out.” The New York Times declared that “autonomous vehicles like the one Google is building will be able to pack roads more efficiently”—up to eight times so. Google co-founder Sergey Brin forecast in 2012 that self-driving cars would be ready in five years, and in May, said he still hoped that his original prediction would come true.

But what Google is working on may instead result in the automotive equivalent of the Apple Newton, what one Web commenter called a “timid, skittish robot car whose inferior level of intelligence becomes a daily annoyance.” To be able to handle the everyday stresses and strains of the real driving world, the Google car will require a computer with a level of intelligence that machines won’t have for many years, if ever.

The problem is not avoiding other traffic or even pedestrians (although how a computerized car deals with jay-walking pedestrians and cyclists is the sort of thing that I would be fascinated to see really work).

The problem is the artificial intelligence to deal with the road and signs itself:

…the Google car was able to do so much more than its predecessors in large part because the company had the resources to do something no other robotic car research project ever could: develop an ingenious but extremely expensive mapping system. These maps contain the exact three-dimensional location of streetlights, stop signs, crosswalks, lane markings, and every other crucial aspect of a roadway.

That might not seem like such a tough job for the company that gave us Google Earth and Google Maps. But the maps necessary for the Google car are an order of magnitude more complicated. In fact, when I first wrote about the car for MIT Technology Review, Google admitted to me that the process it currently uses to make the maps are too inefficient to work in the country as a whole.

And here’s the greatest hard problem of artificial intelligence – unlike humans who can drive roads that they have not previously encountered before or which have temporary signs or speed restrictions to which humans can read and modify their behaviour in response, computerised vehicles need to know where literally everything else is, in advance.

…the maps have problems, starting with the fact that the car can’t travel a single inch without one. Since maps are one of the engineering foundations of the Google car, before the company’s vision for ubiquitous self-driving cars can be realized, all 4 million miles of U.S. public roads will be need to be mapped, plus driveways, off-road trails, and everywhere else you’d ever want to take the car. So far, only a few thousand miles of road have gotten the treatment, most of them around the company’s headquarters in Mountain View, California.  The company frequently says that its car has driven more than 700,000 miles safely, but those are the same few thousand mapped miles, driven over and over again.

Another problem with maps is that once you make them, you have to keep them up to date, a challenge Google says it hasn’t yet started working on. Considering all the traffic signals, stop signs, lane markings, and crosswalks that get added or removed every day throughout the country, keeping a gigantic database of maps current is vastly difficult. Safety is at stake here; Chris Urmson, director of the Google car team, told me that if the car came across a traffic signal not on its map, it could potentially run a red light, simply because it wouldn’t know to look for the signal. Urmson added, however, that an unmapped traffic signal would be “very unlikely,” because during the “time and construction” needed to build a traffic signal, there would be adequate opportunity to add it to the map.

Which brings me to the main point – what are the compelling economic and social reasons why driverless cars are more desirable than ones with human drivers? I can’t see any from here.

Have Google (or anyone else) considered that commuting or simply travelling from one place to another without driving yourself already has a much more economic solution?

I think Google would have better luck with another hard science fiction favourite: the flying car. At least there are no pedestrians or traffic cones up in the air – yet.

It seems to me that the problem could be solved by having a road system built with driver-less transport in mind, but that’s the sort of thing that puts the whole concept in the bracket of “completely uneconomic” or just “hard science fiction”.