The Space Shuttle may have been out of commission for nearly a decade now.

But it's still arguably one of humanity's greatest achievements.

Unlike the rockets and capsules we use today, the shuttle was ideal for short trips to space.

You could launch into orbit, stay there for a couple of weeks to do what you needed to do,

then come home and touch down on a runway like it was just another transatlantic flight.

Thanks to the shuttle, we were able to repair the Hubble Space Telescope multiple times

and build the International Space Station.

Exploration today would be vastly different without it.

But no matter how it seems when you look back on the pictures and videos,

that degree of innovation didn't come easily.

It took more than a decade to design and build the shuttle,

and the thing was so complicated that engineers had to create gigantic, entirely new machines just to make the system work.

The basic idea behind the shuttle was simple enough, at least in theory.

It would launch from a pad in Florida like a regular rocket and spend a week or two in space.

Then, when it was time to come home, the crew would slow it down so it fell back to Earth.

Once the shuttle made it into the atmosphere, it would fly like a plane,

touching down on a runway, usually in Florida, but often in California, too.

Maybe you've spotted the first logistical problem here: If you land a shuttle in California,

you somehow need to get it back to the launchpad on the other side of the country for its next mission.

Sure, the orbiters could fly a lot like a plane when they landed,

but they weren't designed to actually be a plane.

And they were way too big to fit inside even the biggest cargo jets.

So NASA decided to stick them on top of a plane instead.

Or rather, one of two different planes, both modified so they could carry the shuttle on their backs

like some kind of weird speedy flying turtle.

Modifying the planes was pretty straightforward; they just had to add a docking system to the roof.

But getting the shuttle into position on top of the plane, and then taking it back off,

was another story.

For that, engineers invented the mate-demate device, or MDD.

NASA built a few of them, and they were designed to lift the shuttle in a way that would keep it safe and stable

while its carrier plane was either put into position under it or moved out of its way.

Which was not exactly easy to do when the shuttle in question weighed about 100,000 kilograms.

The MDD was a bit like an enormous, stationary double crane.

It had two towers, about 30 meters tall,

connected to a big horizontal beam that was attached to the shuttle to lift it.

Kind of hilariously, the first time NASA used an MDD to try to put a shuttle on its carrier plane,

they realized the orbiter didn't fit,

and they had to adjust some of the attachment points on the plane.

Because, you know, it's not like they use blueprints and measurements for this kind of thing.

But hey, at least they didn't drop the shuttle while they were waiting.

Once the shuttle made it to the launch site,

it was set up on another giant machine: the mobile launch platform.

The platform wasn't built specifically for the shuttle program,

it had been used since the Apollo days.

But it did need to be modified to work for the shuttles.

One major change engineers made was switching out the umbilical towers that had been used to hold the Saturn V,

that's the rocket used for Apollo launches, until it was time for launch.

Instead, the shuttle used two tail service masts,

small structures on either side of the tail that reached up to the bottoms of the wings.

The masts were set up to deliver things like fuel and power to the shuttle, while venting exhaust.

According to NASA's original plan, those changes should have been enough to accommodate the new spacecraft.

But then the first shuttle mission, STS-1, was launched.

And engineers realized they had a problem:

the shuttle's solid rocket boosters were too loud.

Sound carries energy, and when there's enough of it, it exerts a force you can feel.

In the case of the shuttle, the sound was so loud

that it damaged some of the thermal tiles on the outside of the orbiter,

the ones that were supposed to protect it from burning up on its way back through the atmosphere.

Thankfully, the orbiter made it back to the ground safely at the end of the mission.

But if they wanted to keep reusing the shuttles,

NASA knew they had to do more to protect them from the sound of their own launch.

So before the next mission, STS-2,

they installed the sound suppression water system on the mobile launch platform.

Water is much denser than air, and when sound travels through water,

it loses much more energy to the molecules it vibrates along the way.

So, the idea was that a rush of water could dampen the sound and vibrations from the launch,

protecting the shuttle from damage.

And I really do mean a rush.

Like, have you ever seen water gushing out of a fire hydrant at full blast?

This thing made that look like the tiniest raindrop.

In just 41 seconds, it spewed out 1.3 million liters of water.

And it worked!

We actually still use water sound suppression systems today, for rockets like SpaceX's Falcon 9.

The idea might sound kind of crude, but it's incredibly effective.

So, yeah, the shuttles are gone for good, which is a bummer.

But they gave us totally new ways to explore space,

and the machines we built to support their complexity continue to shape human spaceflight today.

If you want to learn about technology that revolutionized the space industry,

you can watch our episode about how computers changed space exploration forever.

And as always, thanks for watching this episode of SciShow Space!

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