Downmass

The word "stevedore" has a great heritage. It comes from the Spanish word "estevador," for "one who stuffs things." Being a stevedore was an occupation for many people working at seaports, where loads of cargo needed stuffing into the holds of freight ships.

Stevedores getting ready to stuff the stuff in with the other stuff on the ship.

 The job of stevedore shouldn't be confused with that of the longshoreman. Longshoremen unload freight ships, stacking the cargo on docks for delivery to warehouses. It's a different skill set, and actually made for two distinct unions during the 19th and 20th Centuries.

Most of us have only a cinematic understanding of  modern dock operations. We think not much has changed since the days of On the Waterfront, where burly, Vic Taybeck-looking guys would offload a ship full of wooden crates with hand-held freight hooks and hemp rope hoists.

If containerized shipping had been established in the 50's, maybe Lee J. Cobb
wouldn't have gotten into that big fist fight with Marlon Brando on the Hoboken docks.

The world's moved on, though. Since 1969, when the US Department of Defense established a standard size for containerized freight, a revolution in cargo transport has changed every job at ports throughout the world. Gone are the days of guys shoving wooden crates into excelsior-lined hulls. Today, the roles of both stevedore and longshoreman have been combined into that of crane operators, a mechanical method of loading and unloading ships without requiring a bunch of guys to crawl all over the cargo. While the number of folks employed by the dockside industry has declined, the amount of merchandise and material shipped worldwide has grown exponentially, expanding employment in related fields such as logistics, transportation, and warehousing.

Today: less Elia Kazan movies, more Denny's Claw games

All this leads up to something going on in outer space next week. On October 7th, SpaceX will launch the first production mission of its Dragon cargo ship to the International Space Station. The previous launch of Dragon was an experiment to see if the process would work - - this time, the cargo is for real.

SpaceX Dragon: this time, it's professional.

Why are the Dragon missions so important? Besides being the precursor to future manned American trips to the ISS, the Dragon is unique among its cargo-carrying rivals (Europe's ATV, Japan's H-III, and the stalwart Russian Progress modules) in that it not only can bring cargo to the ISS, but also bring equipment back to Earth. The other cargo ships are built for one-way trips. They don't have heat shields, parachutes, or any method of surviving re-entry. Even the manned ship, Soyuz, is only capable of returning less than 110 lbs of station equipment back to Earth, and that would only be small things that could fit through the Soyuz's narrow 27-inch hatch.

Puny 27" Soyuz hatch.

Dragon, by comparison, is a proverbial supertanker of downmass cargo. Instead of using the Soyuz probe-and-drogue connector, or even the Shuttle's old PMA linkup, the hatch to Dragon connects directly with any available Common Berthing Mechanism (CBM) port, which allows for a full 50-inch pass through width for equipment. H-III and ATV also use the CBM ports, but as I said before, they can't bring anything back home. The Dragon's downmass capacity (6,614 lbs) equals half the amount it can carry into orbit (13,228 lbs); in fact, this first production ship is going to bring more down than it carries up.

Un-be-freakin'-lievable 50" Dragon CBM hatch.

 How is this such a game changer? Simply, because it's brought the return of downmass capability to ISS operations back to the station program that's been missing since the retirement of the Shuttles last year. Experiments that didn't fit through Soyuz's tiny hatch, or weighed more than 110 lbs were stuck in orbit or doomed to fiery destruction in the old one-way cargo ships. Dragon, built specifically to accomodate the standard ISS experiment rack, makes possible the completion of dozens of station experiments that can now be studied back on Earth. Equipment is now capable of making round trips, so expensive, disabled hardware can be returned to Earth, repaired, and sent back into orbit on a future freight run - - all at a cost about 1/100th of a Shuttle mission.

Round-trip ticket, baby.

A dozen cargo missions by Dragon are scheduled for next year, followed by manned Dragon missions six months to a year after that. The routine-ness and simplicity of Dragon missions will finally make ISS missions safer and more affordable. Like its ocean-going counterpart, the two-way containerization of space cargo will change the economics of space -- for the better.