ASI W9800017r1.1

Moon Miners' Manifesto

#105 May 1997

Section the Artemis Data Book

Aerogel: Windows, Sundows & Other Products for Space Frontier Vehicles & Habitats

Peter Kokh

A Call for Active Investigation and Research

Aerogel is the lightest known solid, literally foamed glass, though it can be made of other raw materials than Silica (Silicon Dioxide, common beach sand, the major component of both glass and quartz), such as Iron Oxide. First developed decades ago, we have begun to see new space age applications and refinements with exiting implications.

Aerogel is translucent, but until a recent manufacturing experiment in space, not quite trans-parent. Previous samples have had a somewhat blurring bluish cast caused by the uncontrollable inclusion of a certain percentage of larger "bubbles" in the froth. Bubble size has now been successfully controlled in micro-gravity, resulting in a product that not only transmits light, but views.

Its density is much less than a batt of fluffed fiberglass, giving it the added attraction of being a storybook insulator. On the other hand, it is quite porous, and could not be used, alone, to contain atmospheric pressure, against a vacuum, for example.

Given this information, what uses can we see for this remarkable material on the space frontier? We will try to give a glimpse of some of the possibilities. But bear in mind that the writer has not been able to find all of the information he considers relevant to such a forecast. Perhaps you can help, and we invite informed reader feedback. Specifically, we have no idea of what kind of mechanical strength the stuff has. Conservatively, we are assuming that it is very weak, that it can be broken, punched through, and snaps when bending pressure is applied.

Aerogel Windows?

The space-made stuff suggests itself as window panes. Maybe on Earth, where pressure differentials are seldom more than a tenth of 1 ATM. But, superior insulating value or not (equivalent of a 5-pack of twin glass thermopanes), there will be little market for it if we can only make it in microgravity. It would be prohibitively expensive.

For space use windows, it would apparently have to be sandwiched between two panes of normal glass. Could they be laminated? Would the glass-aerogel-glass sandwich be lighter in weight than an all glass pressure window? Would mylar be enough? If so, there would be a market for such windows if ever we start co-manu-facturing space stations and vehicles in space itself, for use as in-space ferries, or in amphibious craft that will work as well as lunar or Martian surface vehicles. We have a potential future market, but that's a lot of ifs.

Windows for lunar and Martian habitats? In both cases we have adequate supplies of suitable local raw materials. But the same reservations we brought up for aerogel windows on Earth will apply out there. Can we learn to make the stuff transparent in fractional gravity (1/6th, 3/8ths respectively)? Maybe, maybe not, more likely so on the Moon than on Mars.
If not, and transparent clarity is what we require, such aerogel panes (e.g. made from Lunar Silica in low lunar orbit) would be an expensive option, though perhaps less so than on Earth with its much deeper gravity well up which to bring the raw materials to be transformed. However, if what we want is light, more so than the view, or if we can tolerate a blue haze, we may well see some made-on-Luna aerogel sandwich windows. Might a selling point be superior protection against micrometeorite caused decompression accidents (insofar as, if laminated, the aerogel fill would tend to keep the window from shattering altogether)? A hole in aerogel should be minimal and neat.

Aerogel Thermal Insulation?

Let's look at uses of aerogel that do not hinge on its transparency. Insulation is certainly one of them. As the boxed material on page 5 indicates, aerogel has already been used to insulate the Mars Pathfinder rover, Sojourner. It is not obvious that aerogel (R20/inch!) would be a superior insulating material for lunar and Martian habitats. The lunar regolith (we can only speculate on the heat transmission abilities of various types of Martian soils) is a sufficiently poor conductor of heat that the addition of aerogel batts in habitat exterior walls probably would not be cost-effective. However in unshielded construction shacks, camps, and in surface vehicles, its superior insulating value combined with ultra light weight would make it the unquestioned top choice. But aerogel does not do everything regolith shielding does - it offers no real protection against radiation. Its use as a thermal insulator will likely be limited to the instances suggested above.

Aerogel as Acoustic Insulation?

Aerogel, we assume, is a superior acoustic insulator as well. In limited volume space settlements and lunar and Martian sub-surface communities, reverberating sound could be a very nasty problem. Much attention will be given by habitat and town architects to sound deadening surfaces, sound baffling, and sound insulation. Aerogel could play a major role in making any such settlement livable.

Aerogel, given its minimum weight penalty, could be standard packing in interior space vehicle walls to control on board noise transmission. Any one who is spent time aboard a ship (or a submarine!) knows how important that could be.

Other Aerogel Building Products?

Here are some of the possible lunar building products that could be made with aerogel. Readers are welcome to look for show stoppers in each suggestion as well as to suggest other uses.

Opaque formulations, (by the way, is aerogel "paintable"?) could include:

If the stuff has, or can be given real structural mechanical strength, how about these uses:

Even if aerogel must be laminated to a much stronger structural material, it may find application as the inside surface layer of choice for built-on-the-Moon habitat structures made of local materials because it is much more water-resistant than glass (and by extension, than glass-glass composites, a top candidate material for making lunar habitat hulls). For the same reason, it could be used to line limited pressurized lavatube volumes, the walls previously laser or microwave fused to be air tight.

We must learn more, but the prospects for aerogel on the space frontier seem bright. MMM


Aerogel: Energy-Efficient Material for Buildings

Aerogel Used to InsulateMars Pathfinder Rover (used to be at

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