The station is sometimes described as an object: “The International Space Station is the most expensive object ever created.” “The ISS is the only object whose components were manufactured by different countries and assembled in space.” That much is true. But when you live inside the station for days and weeks and months, it doesn’t feel like an object. It feels like a place, a very specific place with its own personality and its own unique characteristics. It has an inside and an outside and rooms upon rooms, each of which has different purposes, its own equipment and hardware, and its own feeling and smell, distinct from the others. Each module has its own story and its own quirks.
From the outside the ISS looks like a number of giant empty soda cans attached to each other end to end. Roughly the size of a football field, the station is made up of five modules connected the long way—three American and two Russian. More modules, including ones from Europe and Japan as well as the United States, are connected as offshoots to port and starboard, and the Russians have three that are attached “up” and “down” (we call these directions zenith and nadir). Between my first time visiting the space station and this mission, it has grown by seven modules, a significant proportion of its volume. This growth is not haphazard but reflects an assembly sequence that had been planned since the beginning of the space station project in the 1990s.
Whenever visiting vehicles are berthed here for a time, there is a new “room,” usually on the Earth-facing side of the station; to get into one of them I have to turn “down” rather than left or right. Those rooms get roomier as we get the cargo unpacked, then get smaller again as we fill them with trash. Not that we need the space—especially on the U.S. side, the station feels quite spacious, and in fact we can lose each other in here easily. But the appearance of extra rooms—and then their disappearance after we set them loose—is a strange feature most homes don’t have.
Since before the space shuttle was retired, NASA has been contracting with private companies to develop spacecraft capable of supplying the station with cargo and, at some point in the future, new crews. The most successful private company so far has been Space Exploration Technologies, better known as SpaceX, which produces the Dragon spacecraft. Yesterday a Dragon launched from a pad at Cape Canaveral. Since then Dragon has been in orbit a safe 10 kilometers from us. This morning our aim is to capture it with the space station’s robot arm and attach it to the docking port on the station. The process of grappling a visiting vehicle is a bit like playing a video game that tests hand-eye coordination, except that it involves real equipment worth hundreds of millions of dollars. Not only could an error cause us to lose or damage the Dragon and the millions of dollars’ worth of supplies on board, but a slip of the hand could easily crash the visiting vehicle into the station. An accident with a resupply ship has happened before, when a cargo spacecraft struck the old Russian space station Mir, though its crew was lucky enough not to have been killed by decompression when the Progress crashed into its hull.
These uncrewed spacecraft are the only way we can get supplies from Earth. The Russian Soyuz spacecraft has the capability to send three humans to space, but there is almost no room left over for anything else. SpaceX has had a lot of success so far with their Dragon spacecraft and Falcon rocket, and in 2012 they became the first private company to reach the ISS. Since then they have become one of our regular suppliers, along with the Russian Progress and Orbital ATK’s Cygnus, and they hope to be ready to fly astronauts on the Dragon in the next few years. If they can pull that off, they will be the first private company to carry human beings to orbit, and that launch will be the first time astronauts leave Earth from the United States since the space shuttle was retired in 2011.
Right now Dragon is carrying 4,300 pounds of supplies we need. There is food, water, and oxygen; spare parts and supplies for the systems that keep us alive; health care supplies like needles and vacuum tubes for drawing our blood, sample containers, medications; clothing and towels and washcloths, all of which we throw away after using them as long as we can. Dragon will also be carrying new science experiments for us to carry out, as well as new samples to keep the existing ones going. Notable among the science experiments is a small population of live mice for a study we will be carrying out on how weightlessness affects bone and muscle. Each resupply spacecraft also carries small care packages from our families, which we always look forward to, and precious supplies of fresh food that we enjoy for just a few days, until it runs out or goes bad. Fruits and vegetables seem to rot much faster here than on Earth. I’m not sure why, and seeing the process makes me worry that the same thing is happening to my own cells.
We are especially looking forward to this Dragon’s arrival because another resupply rocket exploded just after launch back in October 2014. That one was a Cygnus flown by another private contractor, U.S.-based Orbital ATK. The station is always supplied far beyond the needs of the current crew, so there was no immediate danger of running out of food or oxygen when those supplies were lost. Still, this was the first time a rocket to resupply the ISS had failed in years, and it destroyed millions of dollars’ worth of equipment. The loss of vital supplies like food and oxygen made everyone think harder about what would happen if a string of failures were to occur. A few days after the explosion, an experimental space plane being developed by Virgin Galactic crashed in the Mojave Desert, killing the copilot. These failures were unrelated, of course, but the timing made it feel as though a string of bad luck might be catching up with us after years of success.
No comments:
Post a Comment