Blood and Treasure
Gold, silk, and spices were the tangible treasures from past explorations. Today, the frontier of space offers treasures that are golden but not gold—secrets about the biochemistry of life, drawn from the bodies of astronauts.
Weightlessness poses a biochemical challenge to human space travelers, who develop a host of fascinating maladies such as bone decalcification, cataracts, retina swelling, eye focus shifts, smooth muscle atrophy, fluid imbalance, gross weight loss, cardiovascular degeneration, and more. In spite of these maladies, humans can thrive in space, proving that we are a hardy species that can explore places we were never meant to go.
On the Space Station, we are human guinea pigs for a wide variety of medical experiments. We routinely puncture our veins to draw blood, drool on cotton swabs, and urinate in bags. These samples are processed in centrifuges, sprinkled with preservatives, placed in tubes, and stored in MELFI, better known as “the freezer.” Kept at -98° C, the samples are stored for months before returning to Earth. The cold box ensures unthawed recovery of the samples by ground crews, happy life science researchers, and crew members relieved to know that their bloodletting was not in vain.
European Space Agency astronaut Andre Kuipers, inserts biological samples in the Minus Eighty Laboratory Freezer (MELFI)
The cold boxes themselves are an engineering marvel. They are nearly equal in thermal conductivity to a vacuum dewar (Thermos bottle), but have only a fraction of the mass. They are made from truly space-aged materials—aerogel and Mylar. Aerogel is the most gossamer solid material known. Appearing more like solid smoke, it has a density only ten times greater than that of air (steel has a density 7,000 times greater), making it one of the best thermal insulators known, bested only by vacuum. Aerogel is brittle, and easily crumbles into dust. To prevent this from happening, it is placed inside a skin of Mylar (plastic) film. The air is then sucked out, making this structure as rigid as a vacuum-packed bag of coffee (which feels brick-hard until the package is opened). These Mylar-packed aerogel structures can be made into odd shapes, enabling cold boxes to fit in unused pie-shaped spacecraft volumes.
As with any new technology, unintended uses often surface. Such was the case for the cold box. Developed for space, it ended up in Antarctica—not for keeping things cold but for keeping them warm. In 2006-2007, I had the good fortune to live in a tent about 200 miles from the South Pole during a scientific expedition to Antarctica as part of a meteorite gathering team called ANSMET (Antarctic Search for Meteorites). The conditions found in Antarctica preserve and concentrate meteorites, and for the last 30 years, annual expeditions working during the short Antarctic summers have gathered over 20,000 of them. During our six-week stay, we advanced this number by 850.
A cold box in Antarctica kept electronics warm
Outside our tents, the ambient temperature danced around -20° C even though this was Antarctic summer. With wind chill, the effective temperature was -40° C. At such temperatures, it does not matter what scale is used. In our tents, the floor temperature stayed at -20° C and the chimney varied from -20° C to +20° C, depending on whether the stove was lit. Any water-based substance became a frozen lump. Most electronic devices refuse to operate under these conditions, from batteries that do not make sparks to LCD displays that give only blank stares and hard drives that do not turn at the right speed.
In its former life, our Antarctic hot box had been an engineering test article used to make thermal measurements for the design of the spaceflight units. Having served that purpose, I found it in a NASA cabinet, seemingly of no further use. Brought out from retirement, this high-tech space cooler found itself strapped to a Nansen sledge, pounding through the Antarctic interior over snow structures known as sastrugi. In a cold place, it offered a small oasis of warmth. We also kept our Tabasco sauce and sourdough starter in the hot box, demonstrating the value of having small comforts when living on the frontier.
In such containers we bring back new treasure garnered from the frontier of space. Not gold or spices, but knowledge.