A low point from our recent trip to Thailand:

Left my cool, high-tech travel towel at the last place we stayed. Drat. I’m no longer a hoopy frood…

— Brad Warthen (@BradWarthen) March 12, 2015

This was some sort of super-duper, futuristic towel that my wife had had the foresight to buy before our trip. Small-folding, super-absorbent, and super-fast-drying so you can use it again before long. Whoever found it may not have recognized it as a towel. Its texture was like a cross between felt and rubber — hard to describe, really.

I had thought it really cool that, like a Douglas Adams character, I was a traveler who always knew where his towel was — in his backback:

Somebody who can stay in control of virtually any situation is somebody who is said to know where his or her towel is. The logic behind this statement is presented in chapter 3 of The Hitchhiker’s Guide to the Galaxy thus:

… a towel has immense psychological value. For some reason, if a strag (strag: nonhitchhiker) discovers that a hitchhiker has his towel with him, he will automatically assume that he is also in possession of a toothbrush, washcloth, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet-weather gear, space suit etc., etc. Furthermore, the strag will then happily lend the hitchhiker any of these or a dozen other items that the hitchhiker might accidentally have “lost”. What the strag will think is that any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is, is clearly a man to be reckoned with.

Technically, I still knew where it was — I had left it on a doorknob of a farmhouse in the countryside of Khorat. But I no longer had the use of it, which of course was the point of such knowledge. I also had most of those other things listed in the above paragraph, and more — just not my towel, which saddened me, because it made me feel less hoopy.

But now I read that in the future, a space traveler’s most critical accoutrement will not be his towel. In fact, “A 3-D printer may one day be in the carry-on luggage of every savvy solar system traveler…”

They are experimenting with a 3-D printer that would make bricks suitable for airtight buildings and radiation-proof shelters using the grit that blows across Mars’s red surface.

In Huntsville, Ala., Ms. Werkheiser, NASA’s 3-D print project manager, is starting to print curved walls and other structures using imitation Martian sand as an ink. Engineers at the European Space Agency are exploring ways to use lunar dust as an ink to print out an entire moon base. London-based architects Foster + Partners have designed a printable lunar colony.

And if astronauts ever do attempt to reach Mars, they may survive the journey by eating pizza made with a 3-D-printed food system for long duration space missions, now under development in Texas…

These printers will use materials found on the moon and on Mars as “ink.”

Frankly, on this topic I’m a little like those people who believe the moon landings were a hoax. I DO believe in the moon landings, let me be clear, but I still don’t understand how any sort of complex item — say, pizza — can be recreated so that it is functional. I see how you might print a plastic statue of the object; I just don’t understand how it could work like the original.

In other words, I can imagine having something like a low-functioning 3D PDF — like a fax that is a picture of text, but doesn’t give you text that you can work with, because the document does not know that the text is text. If you can follow me.

But the boffins say it will work. If so, I suppose, in the future you won’t need to have your towel, because you can always print another…