Tuesday, April 10, 2012

When Nothing Means Something

Edgar Rice Burrough’s Pellucidar describes a great airship that derives its buoyancy from a whole lot of nothing...a vacuum. Thanks to technological advancements, that concept is now a lot less laughable than the movie version of John Carter (victim of yet another battle scifi screenwriters lost to physics). It is the holy grail of lighter-than-air craft because it doesn’t require helium (expensive) or hot air (cools off). Although a vacuum is only slightly better than hydrogen at lifting, it doesn’t burn and it only requires a little electricity and a vacuum pump.

With the purchase of your groceries and this device, you get free trash bags for life. 

To facilitate this concept, Finnish scientists have now come up with something almost as good as saunas; “nanocellulose aerogels.” To give you a better idea of what we are talking about let me quote from the article...”a boat made from 1 pound of the substance could carry five kitchen refrigerators, about 1,000 pounds.” The article is here - Materials Inspired By Mother Nature.

An aerogel is a synthetic porous gel from which the liquid has been removed leaving a matrix of ethereal but structurally sound material. Wikipedia has a fine article on the subject of aerogels. A nanocellulose aerogel is, essentially, an aerogel made from plant fiber. At some point, using some substance like graphene or radioactive spider silk, there will be a super aerogel that exceeds all other substances and previous aerogels in its strength to weight ratio.

Brick supported by a pad of aerogel.
Image courtesy of NASA

Now what if we had a structure of such aerogels, like the ribs and stringers of an airplane wing, wrapped with an airtight envelope of thin, tough, impermeable lightweight plastic? This structure and skin would be capable of withstanding the 14 pounds per square inch of atmospheric pressure as the air is sucked out. It would be fabricated in the shape of a wing or lifting body to add to it's lift capability in flight. With vacuum providing buoyancy there is no deformation of the lifting cell as it goes higher and higher into the atmosphere. Cover with solar cells, attach passenger/freight pods and electric engines with props and voila; cheap air travel. Besides taking you from New York to LA for $100, it would make a great firefighting, logging, and rescue vehicle.

Let’s think beyond my tirades about how we should have a cheap, leisurely, environmentally friendly alternative to air travel in addition to the expensive, fast, petrol-based air travel. Let’s think about how to get really high...like off the planet. Imagine giant donut-shaped vacuum blimps stacked 10,000 feet apart vertically. They each support a 2-mile segment of a 6-10 foot diameter sleeve of pressurized carbon nanotube film. Up and down this tube would move balloon-tired crawlers transporting passengers to and from a hotel floating at the top of the tube on the edge of space 26 miles above the Earth. Imagine sipping on a mojito under millions of unblinking stars amid the blackest background you've ever seen, gazing at the curving horizon of the blue Earth 450 miles away. If the last lifting donut is large enough, it might even sport a space vehicle launch platform as well as the hotel. That 26-mile head start would save a lot of fuel every launch.

The answer to the plastic bag problem is reuse. This new device makes it easy. 

Further, this could serve as the first leg of a space elevator stretching to a space port in geosynchronous orbit. It could lower the cost of reaching space to the point humankind can afford to explore space and do the things we need to do to insure our future. We can mine the asteroids for precious metals, scour the Moon for Helium3, and build solar collectors to provide us the energy we need when our fossil fuel runs out.

Glen Hendrix
author Transmat World

1 comment:

  1. You can find instructions for making your own aerogel, as well as information about the many varieties of aerogel that have been synthesized (such as strong and flexible aerogels), at www.aerogel.org.