When your slice of bread falls on the floor, everyone anxiously looks to see if it landed jelly side up or jelly side down. Simple probability gives a 50-50 chance either way, but it seems more correlated to the difficulty of cleaning that particular section of flooring.

On space station the probabilities are still the same, but the results are different. I fumbled my bread after spreading a generous layer of my favorite concoction, peanut butter and honey. It sped toward the overhead panel and hit it before I could intervene. Fortunately, it landed jelly side out (it’s interesting how many figures of speech have gravity-oriented references), so the 50-50 odds were in my favor this time.

Unfortunately, it ricocheted and sped off in a different direction. I noticed that the angle of incidence equaled the angle of reflection. My earth-honed intuition anticipated a different motion, so I was not able to keep up with the errant slice. Like a real-life version of the game “asteroids,” it went on to hit a second panel. Jelly side was out again, so the 50-50 statistics were still in my favor. One more time my hand was lagging the trajectory. Like failing to flip heads three times in a row, the third collision was jelly side in, which immediately halted all motion. And just like on Earth, the outcome seemed related to the difficulty of cleaning the landing zone. After having hit two easy-to-clean aluminum panels, it landed on a white fabric covering on a patch of Velcro pile.

The fatalist in me accepts the inevitable Zero-G result of landing jelly side “down,” so I decided to make sure the probability would always be 100%. Realizing that the bread is merely a vehicle for conveying peanut butter and honey, I decided to spread it on both sides. In weightlessness, it’s easy to balance your slice on its edge so that it can be parked on the galley table without any fuss. And the result is pure tastebud heaven. I do it this way because I am in space, and I can.

Don's blog also appears at airspacemag.com. 

The International Space Station was conceived and constructed through the cooperation of fifteen nations. Now, with it's construction complete, we can focus on how best to use it.

We have built a laboratory located on the premier frontier of our era. Our Earth-honed intuition no longer applies in this orbital environment. On frontiers, things do not behave the way we think they should, and our preconceived notions are altered by observations. That makes it rich in potential for discovery. The answers are not in the back of the book, and sometimes even the questions themselves may not be known.

Getting ready to insert biological samples in the Minus Eighty Laboratory Freezer for ISS (MELFI-1) in the Kibo lab.

On the Station we can use reduced gravity as an experimental variable for long periods of time. We have access to high vacuum, at enormous pumping rates. (The rate at which space can suck away gas, hence its ability to provide a region devoid of molecules, far outpaces anything we can do on Earth.) We are beyond the majority of our atmosphere, which lets us touch the near-space environment where solar wind, cosmic rays, and atomic oxygen abound. Such cosmic detritus, unavailable for study within our atmosphere, holds some answers to the construction of our universe and how our small planet fits into the picture.

The Station as a laboratory offers most of the features that Earth-borne laboratories have, including a good selection of experimental equipment, supplies, and a well-characterized environment (temperature, pressure, humidity, gas composition, etc.). There is generous electric power, high data-rate communications, significant crew work hours (the fraction of hours spent on science per crew day on Space Station is commensurate with the fraction for other science frontiers such as Antarctica and the deep ocean), and extended observational periods ranging from weeks to years. All this is conducted with a healthy blend of robots and humans, working together hand-in-end-effector, each contributing what each does best. Only on Earth is there a perceived friction between robots and humans.

In this orbital laboratory, we can iterate experimental procedures. We can try something, fail, go back to our chalk board, think, (we now have the time for this luxury) and try it all over again. We can iterate on the iteration. We now have continuous human presence, and time to see the unexpected and act upon it in unplanned ways. Sometimes these odd observations become the basis for studies totally different from those originally planned; sometimes those studies prove to be more valuable. And on this frontier the questions and answers mold each other in Yin-Yang fashion until reaching a natural endpoint or the funding runs out, whichever comes first. This is science at its best, and now, for the first time, we have a laboratory in space that allows us to do research in a way comparable to how we do it on Earth.

So what questions are ripe for study on the Station? What possible areas of research might bear fruit? We have a few ideas.

One area is the study of life on Earth. Life has survived for billions of years, during which temperatures, pressures, chemical potentials, radiation, and other factors have varied widely. Life always adapts and (mostly) survives. Yet there is one parameter that has remained constant for billions of years, as if our planet was the most tender of incubators. Now for the first time in the evolution of life, we humans can systematically tweak the gravity knob and probe its effect on living creatures. And we can change the magnitude of gravity by a factor of one million. Try changing other life-giving parameters, perhaps temperature, by a factor of one million and see how long it takes a hapless life form to shrivel up and die! The fact that gravity can be changed by many orders of magnitude and life can continue is, in itself, an amazing discovery. So now we have a laboratory to probe in-depth the effects of microgravity on living organisms.

The discovery of fire (or rather its harnessing) was a significant advance that allowed humans to transcend what we were to become what we are now. Well before Galileo and Newton dissected the basic formulations of gravity, humans intuitively understood that heat rises. We empirically learned how to fan the flames. But fire as we know it on Earth requires gravity. Without gravity-driven convection, it will consume its local supply of oxygen and snuff itself out as effectively as if smothered by a fire extinguisher. Questions about fire (up here we prefer the term “combustion”) are ripe for a place where we can tinker with the gravity knob.

Another invention, the wheel, literally carried us into the Industrial Age. Ironically, that particular tool is rendered obsolete on a frontier where one can move the heaviest of burdens with a small push of the fingertips. In space the problem is not how to move an object, but how to make it stay put. Perhaps the invention of the bungee cord and Velcro will be the space-equivalent to the development of the wheel on Earth. Such shifts in thought and perspective, some seemingly minor, happen when you observe the commonplace in a new and unfamiliar setting.

We are now told that we may only be seeing about 4 percent of the stuff that our universe is made of (which raises the question, what is the other 96 percent?). Some questions about fundamental physics can only be made outside our atmosphere or away from the effects of gravity. The International Space Station, contaminated with human-induced vibrations, may not be the ideal platform for these observations, but it is currently in orbit and is available to be used. Many of these experiments are like remora fish, latching onto an opportune shark for a sure ride instead of waiting for the ideal shark to swim by. And we pesky humans, even though we cause vibration, occasionally come in handy when some unexpected problem requires a tweak, a wrench, or simply a swift kick.

Although we have preconceived ideas about how the International Space Station can be utilized, benefits of an unquantifiable nature will slowly emerge and probably will be recognized only in hindsight. The Station offers us perspective; it allows us to question how humans behave on this planet in ways that you can’t when you live there.

It is not surprising that the humble garbage can, essential for Earth-borne civilization, is likewise essential for space station. Unlike the kitchen wastebasket, an omnivore that will eat just about any trashy thing, on space station our wastebaskets are picky eaters.  We sort our trash into a number of different categories different from the standard earthly recycle bins of paper, plastic, and glass.  The main categories are: dry trash (paper towels, food packaging, empty drink bags, paper items, etc.), wet trash (pouches and wrappers with food residue), spent batteries, life support systems expendables (fluid sample bags, toilet hoses, connectors, etc.), experimental expendables (used medical supplies, containers filled with leftover nasty things, etc.), and toilet waste (sealed buckets of you know what).  Some of our trash items have bar codes and serial numbers and require bookkeeping paperwork at the time of disposal.  Like happens at home, sometimes an item is tossed that is later discovered essential so we go orbital dumpster diving for its recovery.  Like passing through a miniature asteroid belt, in weightlessness such an operation can create a cloud of floating debris that is challenging to put back into its container.

One characteristic of an orbital trashcan is that it is always full.  When I change out a trash bag, within a short time it is once again full.  Like a gas expanding into a vacuum, items placed inside expand into the available volume thus giving the appearance of a full bag.  Unlike an ideal gas expanding into a vacuum, here the change in entropy is not zero.  Placing new items into such a bag is really an act of compression.  The trash is squeezed and compressed until the placing of one more item requires greater strength than your arms can supply.  At that point the bag is sealed with duct tape.  The final disposal is via Progress, the spent Russian cargo vehicle (and now we also can use ATV and HTV, the European and Japanese cargo vehicles).  The ultimate disposal of our garbage is thus via deorbital cremation.

During interviews from space station with school children I am often asked what on Earth I miss the most.  On one occasion a little girl asked a most astute question, “What from space will you miss the most once you return to Earth”?  I had to think for a moment.  Was it the views of Earth, a blue jewel surrounded by inky blackness, the heavens filled with stars that don’t twinkle, or perhaps the aurora, pure occipital pleasure seen on the length scale of half a continent?  I decided it was none of these.  Such wonders can be experienced in some form from Earthly perspectives.  What is truly unique to living in orbit is a byproduct of being weightless.  Here I can fly.  I can fly without wings dictated only by Newton’s laws of motion without the complications of aerodynamics.

As subjects of Earth, we grow up with no innate knowledge of maneuvering in weightlessness.  This is a skill that has to be learned on the job.  In a matter of minutes, we can learn to move about but to gracefully conduct ourselves takes a few weeks.  During my first expedition, after a month I thought, “Wow, I am really getting good at this”.  Then another month went by and I would think, “Last month I thought I was really good but now I am really getting good”.  I found this pattern repeated over the six month mission.  When I returned to space station as a space shuttle crew member on Endeavour, our mission was only 16 days, a mere flash in the pan by space station standards.  Sixteen days is barely enough time for your bowel to become regular let alone learn how to translate in weightlessness.  Newly arrived Shuttle crew members typically would miss a hand rail and bounce off of a rack panel with the same grace as an albatross coming in for a landing.  There would be a cloud of items knocked off of their Velcro wall tacking in their wake.  The station crew members were constantly following our shuttle crew picking up the flotsam.  One station crew member mocked, “Next time before the shuttle arrives I will have to kid-proof the stack”.   

To improve your translation skills, it helps to apply some basic concepts of physics.  When flying like “Superman”, the first and most natural method for beginners to translate, your arms are outstretched in front thus grasping onto any fixed object in which to give a little push or pull as well as offering a measure of security for protecting the tender parts on top of the head.  But this is not the best way to fly.  In this position your center of gravity is located somewhere around the belly button so controlling motion with outstretched arms also imparts rotational components and complicates the movement.  Beginners flail with these yaw and pitch motions and struggle to compensate for their unwanted effects.  Thus I learned the best way to fly is head first with arms at your side like “Ironman”.  Pushing and pulling from this position goes nearly through your center of mass, thus does not impart rotation.  On space station Ironman becomes your role model for flying, leaving Superman for the comic books. 

With practice I progressed from flying like Ironman to fly-walking.  Fly-walking looks like normal walking with the body “standing upright” and motion perpendicular to the chest.  In fly-walking your motion is controlled by the legs through tactful forces exerted through the feet when hooked under a deck mounted handrail.  This motion does not seem possible, however; when pressed into a new environment, humans readily discover, learn, and adapt.  Fly-walking offers a real advantage because it frees your arms for carrying loads.  

There is recreational flying.  This is fun flying, perhaps in a gymnastic pike, an iron cross, or a cannon ball.  You try to shoot down a module corridor without touching anything thus having a visceral experience with the First Law of Motion.  We fly like this for no reason other than you are in space and you can.  It is the equivalent of a kid skipping to school.  In the frontier we once again become school kids.

He flies through the air with the greatest of ease 

goes the daring young man, without his trapeze 

Drifting around, unconstrained by his girth 

free of the weight he acquired by birth 

A place where you won't be skinning your knee 

where the biggest problem is "How does one pee?" 

(it is best to avoid preflight coffee or tea) 

Like flying in dreams, which you know can't be 

yet it’s real as life, in the absence of g