An Unlikely Comparison: A Subway Car, the Enterprise, and Mir Space Station

“Doors Closing!”

Those of us from the Washington, DC region recognize that phrase whenever we ride the Washington Metro. That recorded voice is typically followed by another stern voice, “STAND CLEAR OF THE DOORS!” It doesn’t seem to do much good; there are always one or two passengers who insist on standing in front of the doors, blocking the way for those who wish to get on or off.

I was reminded of this the other night, as I was surfing through television channels and came across a “retro” channel that was showing original episodes of Star Trek, in glorious high-definition color on my big-screen digital set. When the original series was shown, between 1966 and 1969, I hardly ever saw any episodes, as I did not own a television at the time, never mind color. With the Star Trek starship Enterprise studio model now on display in the Boeing Milestones of Flight Hall, I find myself watching the show with increased interest. I noticed that in a number of these episodes the crew members approach a sliding door, which automatically opens with a slight “whoosh!” then closes behind them, much like they do on the Washington Metro. The Metro doors are slightly curved, presumably to give the cars more structural strength, but they also look pretty cool, too, even if they are a bit long in the tooth these days. The Metro cars definitely look like they came from the space age in 1976, when the Metro opened, and when the Moon landings were still a part of people’s collective memory. If no one is blocking the Metro doors, they also make a reassuring sound as they open and close.

Along with the sliding doors in Star Trek is the clean, uncluttered look of the starship Enterprise. Borrowing from the Navy tradition, it is truly “shipshape.”  No dirt, no clutter. The consoles are clean and have none of the papers and even ash trays seen, for example, at the consoles of the Mission Control Room at the Johnson Spaceflight Center during the Apollo era. 

Beginning in 1986, reality caught up with fiction in the form of the Soviet, later Russian, Mir space station. It was not the world’s first space station, but it did have some unique features that in some ways were a fulfillment of the Star Trek vision nearly two decades before. Like the Enterprise, Mir flew only in space, never approaching any planet with an atmosphere. It eventually carried an international crew, who had to get along with one another even if their host countries had been at odds with each other. Its crews at times included women, who worked as equals among their male counterparts. And like the Enterprise, the Mir experienced a number of near-catastrophic events, which required quick and correct actions from its crew, sometimes with little opportunity for help from ground controllers.

One of the most dramatic of the latter events took place in June 1997. An unmanned “Progress” ship, carrying supplies for the station, collided with Mir and caused a breach in the hull. It was, “the first decompression aboard an orbiting spacecraft in the history of manned space travel,” according to Bryan Burrough in the book Dragonfly: NASA and the Crisis Aboard Mir. American astronaut Michael Foale felt the collision, and the popping of his ears told him that the station was losing pressure. He immediately knew that there was indeed a collision, but he also sensed from the popping of his ears that it was not catastrophic and with luck would not require the abandonment of the ship. Foale was correct, the breach, though serious, was not causing a sudden and complete decompression. The decompression was gradual, and it occurred in one of the modules of the station that could be sealed off by closing a hatch. If the crew could close the hatch in time, the rest of the station would remain habitable and its atmosphere could be gradually restored to a normal level.

In the Star Trek franchise, attacks on the hull of the Enterprise are common. The crew, led by Captain James Kirk, acts decisively and heroically to save the ship from disaster. As far as I can tell, however, no episodes of Star Trek show a loss of cabin pressure, nor a popping on the crew’s ears, to indicate that such a breach occurred. It is a bit of artistic license, acceptable in order to keep the plot moving.

There is another, in my mind more serious, difference between life aboard the Enterprise and its real-life counterpart, Mir. In the absence of gravity, there was no need to store things in assigned places when they were not being used. Cables and hoses carrying communications signals, power, oxygen, and fluids were haphazardly strewn across the station in an ad-hoc fashion. Over its lifetime the Mir became increasingly cluttered, like a college freshman’s dorm room. Captain Kirk would not have approved, but since there would never be a time when Mir experienced gravitational forces (unlike for example, the space shuttle), there was not much incentive to keep it shipshape. The lack of orderliness became a minor annoyance, until it eventually had more serious consequences.

That has to do with passages between sections of the space station. On the Enterprise, as mentioned, doors slide smoothly and automatically as one moves from one section to another. On the Mir, the modules were connected by circular hatches, patterned after those used on submarines and designed to make a tight seal for the same reason submarines use them. In the response to the hull breach of June 1997, however, things did not go smoothly. The hatch connecting the “Kvant” module, where the breach occurred, to the rest of the Mir was cluttered with cables, hoses, and other obstructions. Before the hatch could be closed, these had to be removed. Russian cosmonaut Alekzandr Lazutkin quickly went to work disconnecting cables and moving them out of the hatch. Michael Foale was behind him, gathering up the disconnected cables and tying them out of the way. Three of the cables had no obvious place where they could be unplugged, so the crew cut them with a knife. They cut two, but the third resisted. With the air still leaking out, they found the end of the third cable, disconnected it, and pulled it out of the hatch. They covered the hatch with a lid, and the loss of pressure stopped. The Mir was saved.

Mir has an odd place in history, not only because of the troubles it experienced during its lifetime. Mir was eventually replaced by the International Space Station (ISS), whose crews and ground controllers have learned the lessons of Mir. The ISS consists of a series of interconnected modules, which like Mir can be sealed off if necessary. Cables carrying power and data from one module to another are typically routed outside the station—avoiding the safety issue but requiring difficult spacewalks to install and maintain them. There is still no need to keep everything neat and clean, but it is far less cluttered than its predecessor. Still, the ISS looks nothing like the fictional Enterprise or the Deep Space Nine station. Perhaps the next generation space station will look that way, complete with smooth sliding doors between modules, instead of those hatches that remind me of World War II movies about submarine warfare. Let’s also hope the doors on the Washington Metro continue to work smoothly, too.