My good friend Jeff Mann, the true Yard Ramp Guy, has asked me to revisit some of my original posts. This week in my From the Archives series: my entry that closed out the year. (Oh, the year was 2015.)

There's an enormous underground chamber just north of Tokyo. The Underground Temple—also known as the G-Cans Project, or the Metropolitan Area Outer Underground Discharge Channel—is a flood water diversion facility.

“Enormous” might be an understatement. It’s more than 25 meters high and 177 meters long. The concrete room is held up by 59 immense, 500-ton concrete pillars. In addition to the main chamber, there are five huge underground silos, each 65 meters deep and 32 m­ in diameter. You could quite literally fit Godzilla in one of those.

Construction on it began in 1992 and didn't complete until 2009. The whole thing is essentially the world's largest drain. The silos and the Temple are linked by hundreds of miles of underground pipes. The entire complex is nearly four miles across.

Tokyo has suffered from frequent floods throughout its history—not just from heavy rain, but also from typhoons and tornadoes. G-Cans was built to withstand even the most massive, once-every-other-century floods. Its 14,000 hp turbines and 78 pumps are capable of pumping more than 200 tons of water per second into the nearby Edogawa River.

"It was THIS big!"

The architects and construction crew faced a number of major difficulties in the construction. Earthquake proofing was one of the biggest hurdles. Another: preventing buckling and sagging in the ground overhead as they dug out the complex; it is directly underneath a city, after all.

There was a little criticism about the steep price tag ($2 billion) and the fact that Tokyo already possessed significant flooding defenses. Still, given how prone to natural disasters the city is, I certainly think they made the right call.

So, they have the flood prevention thing covered. Of course, there are still earthquakes, volcanic eruptions, tsunamis, typhoons, Godzilla, and those horrifying giant Japanese hornets to worry about.

My good friend Jeff Mann, the true Yard Ramp Guy, has asked me to revisit some of my original posts. This week in my From the Archives series: Japanese floods. And earthquakes. And Godzilla. Oh, my.

There's an enormous underground chamber just north of Tokyo. The Underground Temple—also known as the G-Cans Project, or the Metropolitan Area Outer Underground Discharge Channel—is a flood water diversion facility.

“Enormous” might be an understatement. It’s more than 25 meters high and 177 meters long. The concrete room is held up by 59 immense, 500-ton concrete pillars. In addition to the main chamber, there are five huge underground silos, each 65 meters deep and 32 m­ in diameter. You could quite literally fit Godzilla in one of those.

Construction on it began in 1992 and didn't complete until 2009. The whole thing is essentially the world's largest drain. The silos and the Temple are linked by hundreds of miles of underground pipes. The entire complex is nearly four miles across.

Tokyo has suffered from frequent floods throughout its history—not just from heavy rain, but also from typhoons and tornadoes. G-Cans was built to withstand even the most massive, once-every-other-century floods. Its 14,000 hp turbines and 78 pumps are capable of pumping more than 200 tons of water per second into the nearby Edogawa River.

The architects and construction crew faced a number of major difficulties in the construction. Earthquake proofing was one of the biggest hurdles. Another: preventing buckling and sagging in the ground overhead as they dug out the complex; it is directly underneath a city, after all.

There was a little criticism about the steep price tag ($2 billion) and the fact that Tokyo already possessed significant flooding defenses. Still, given how prone to natural disasters the city is, I certainly think they made the right call.

So, they have the flood prevention thing covered. Of course, there are still earthquakes, volcanic eruptions, tsunamis, typhoons, Godzilla, and those horrifying giant Japanese hornets to worry about.

My good friend Jeff Mann, the true Yard Ramp Guy, has asked me to revisit some of my original posts. This week in my From the Archives series: it's either space junk...or me, trying to make a pizza.

Space Junk

In 2013, director Alfonso Cuarón came out with Gravity, a movie about junk. Specifically, it's a movie about space junk.

In the film, a missile strike on a satellite results in a runaway chain reaction of collisions between space junk and satellites. This brings down space stations, satellites, and spacecraft left and right, rendering Earth's orbit useless to manned travel. 

Gravity is an excellent movie, and we’ll forgive a few scientific inaccuracies, since they're all in service of the plot. (Neil Degrasse Tyson, despite his multiple criticisms of the science, is a fan of the film.)

The threat in Gravity is a very real one. It's a scenario known as Kessler Syndrome, where space debris collides with space debris, generating more space debris, which collides with yet more space debris, until that specific orbit around Earth is so filled with debris that it is rendered nearly useless for human purposes. (Low Earth orbit is the most likely orbit to be lost to this process, though geosynchronous orbit is another possible victim.)

Being Geosynchronous

It's not astonishing that this is a serious concern for NASA and other space scientists. There are more than 2,000 satellites in orbit, about 1,500 of which are operational, along with nearly 18,000 trackable artificial objects.

Smaller objects are even more common—at least 29,000 chunks of debris in orbit that are more than 10cm in size, nearly 700,000 between 1-10cm in size, and 170 million chunks of debris below 1 cm in size.

Even with how spacious Earth's orbit is, there's a very high chance of impact, and at least one satellite is destroyed by debris every year. Space junk is a serious threat even if it doesn't trigger Kessler Syndrome.

Steps are being taken to combat the risk. We're tracking debris much more carefully than ever right now. The International Space Station and other spacecraft have special protective layers known as Whipple shield: instead of building hulls out of thicker material, engineers add an extra thin layer some distance over the regular hull. The layer isn't meant to stop the debris but to break it into smaller chunks. In essence, Whipple shield turns debris from a bullet into birdshot. It even makes the needed thickness for the inner hull much smaller, so overall spacecraft mass is actually reduced.

And this: we’re developing a technology known as a laser broom. Targeting a laser on debris will heat up one side of the debris. The resulting heat emissions will then alter and destabilize the debris' orbit, causing it to burn up in the atmosphere.

Like me, trying to make pizza.