Slicing Up Time on the Space Station
A Slice of Time Pie
Posted on Jun 22, 2012 04:43:36 PM
If my day on Space Station were a pie, it would be sliced into many wedge-shaped slivers.
It begins with a small slice for waking up, hygiene, and a bag of coffee (even in space, it is comforting to have a morning routine.) This is followed by a slice for reviewing and organizing the tasks that will make up my work day. I might make a list of tools so that when I float to the tool box, I can gather everything I need in one trip. Then we have a morning conference with mission control.
Our work day then begins, consuming a 12-hour slice of time pie. At the end of the workday, we have another conference with mission control, followed by about an hour of work tying up loose ends. Then there is a slice for crew dinner. It is not unusual to work the whole day without seeing your fellow crewmembers at all (Space Station is a big place), and it is important to gather over a meal to exchange stories. This fulfills a very human social requirement, probably done since the discovery of fire, when the tribe would gather around the burning embers after the hunt (we now gather around our electric food warmer).
This leaves about a nine-hour slice of off-duty time until the whole routine begins anew. Note well that this is not “free time” but “off duty time”—a significant distinction when living on a ship, be it on the ocean or in space. Sleep comes in your off-duty time, and depending on how much you need, determines the size of the leftover slice of personal pie. All of us have families and friends, and if we want to gracefully return to our places on Earth at some point in the future, they require sharing a significant piece of your personal pie. At the end of the day, I am lucky to have an hour slice of truly personal time, often spent in the cupola gazing at the cosmos (writing these essays comes from this slice and competes with window time, which accounts for some of the delays between postings).
A plant sprouting in a aeroponic bag on the International Space Station. While on the ISS, Don Pettit and the Expedition 31 crew are peforming experiments to study how Earth life adapts to the conditions of low Earth orbit. Credit: Don Pettit
By far the largest slice of time pie is the 13-hour on-duty workday. Of this wedge, about 6½ hours is working primary mission tasks. These include scientific and engineering research, operational tasks such as flying the robotic arm and spacewalks, and spacecraft system maintenance/repair. The balance of the workday is spent on the necessary upkeep and overhead to enable the 6½ hours of time on task. This includes our 2½ hours of physical training (maintains crew health), transfer and stowage of new supplies from visiting —Progress, European ATV, Japanese HVT and the commercial vehicles, Dragon and (soon) Cygnus)—inventory and audits of existing supplies, managing our trash, conferences with mission control (some days we will spend 15% of our time talking to them), lunch, toilet, unplanned repairs (e.g. network, laptops, toilet, drinking water problems, etc.), and simply searching for needed items (often times not found in their proper place).
While achieving only 6½ hours work out of every 24 hours on mission tasks may seem appalling, it is commensurate with Earthly efforts when working in harsh frontier environments. When I was deployed with the Antarctic Search for Meteorites (ANSMET) team on a remote glacier field about 200 kilometers from the South Pole, we toiled for about 14 hours a day to enable 6 hours of our mission’s work; hunting for meteorites. A good slice of this Antarctic time pie (obviously a frozen dessert) was taken for such supporting tasks as snowmobile maintenance, gasoline stove fuel management, shoveling snow to keep our Scott tents from becoming buried, latrine maintenance, cooking and food management, melting ice for drinking water (a big time sink), drying sweaty clothing, and simply trying to stay warm. Considering the harshness of the Antarctic interior, it was fortunate we could spend six hours a day on the mission task. The same sorts of numbers are seen in deep ocean efforts, particularly if the divers are living under high-pressure, saturated gas conditions (pressurized living quarters that are at the same pressure as the equivalent ocean work depth). When humans venture into a harsh wilderness, the fraction of time on task shrinks while the effort to simply be there grows. In any of these settings, you are lucky to log six hours of mission tasking and six hours of sleep. The rest of the time is spent simply trying to stay alive.
NASA has invented a machine that mimics the experience of weightlifting on Earth. Exercise is an important part of the daily routine on the ISS. Credit: Don Pettit
On weekends we have off-duty time, but never a free weekend. On Saturdays, we are scheduled for six hours of on-duty time, mostly housekeeping duties where we vacuum filters and swab the decks. On Sundays, our lightest workload, we have about 3½ hours of tasking (this includes our 2½ hours of exercise). To date, we have had four weekends in a row where something came up that trumped our off-duty time. One was for an electrical failure in the ATV cargo ship that if uncorrected, would have required an emergency undocking with possible loss of all our new supplies. One was for a possible near collision with a piece of space junk, where we had to close all the hatches to make station “watertight” and then hide in our Soyuz spacecraft. Another was to fix the toilet after it failed, and one was for our regenerative water processor (the coffee machine). During this period we worked over 30 days without a break. When you go to the frontier, you are there to do something productive, not to sip tea and eat bonbons.
Organization is the key to using personal time effectively. I have a 5-, 15-, and 30-minute plan in my pocket, so when there is a pause in the mission work, I know exactly how to use the moment productively. Then, when you truly have a significant span of off-duty time, perhaps on a Saturday night, there is nothing more awe inspiring than floating for an orbit in the cupola and observing the Earth. My personal slice of time pie may be only a sliver, but oh, how sweet it is!