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Hey Dunn. Hey Robert. Thanks for meeting us. This is my friend Van. Hi. Hey Van. How are you doing? Good.

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Well, Van and Jennifer, I'd like to welcome both of you to the NASA Marshall Space Flight Center and to our historic test area.

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Van, we understand that you're involved in a bike race and in any race it's important to understand where you've been before you figure out where you're going.

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Some pretty historic boosters were tested right here in these test areas.

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The measurements taken here on the ground were used to calculate how the real thing would operate in flight.

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And what they did was some truly amazing things.

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You know, it wasn't that long ago that when people talked about something that they thought was impossible to do,

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they'd say, you've got as good a chance of doing that as going to the moon.

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Tranquility Base here. The Eagle has landed.

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I bet NASA doesn't hear that one too much anymore.

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Yeah, this is really cool, but how can it all be related to my problem with the bike race?

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Well, Van, let's take a look at what NASA's doing on its next generation X-plane, which in part is being tested right in this area.

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What is an X-plane?

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Van, an X-plane is an experimental aircraft built specifically for research purposes.

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This is one of the latest X-planes. It's called the X-33.

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This is a 1 to 50 scale model of the X-33, which itself is a scale model of what we're ultimately after,

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which is a single stage-to-orbit reusable launch vehicle that Lockheed Martin refers to as VentureStar.

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What is a thermal protection system, or TPS?

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Name two examples of thermal protection.

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The X-33 demonstrator will fly and test out the technologies needed to make going into space more common

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by making it more affordable and more reliable.

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It takes off vertically like a rocket and lands horizontally like an airplane.

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The X-33 is designed with advanced hardware that will dramatically increase launch vehicle reliability.

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The vehicle is designed to reach altitudes of 60 miles and travel at velocities up to 13 times the speed of sound.

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Well, what do you mean by velocities?

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Velocity is simply the speed at which something is moving.

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Try hitting the atmosphere when you're moving at super velocities,

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and the friction of air molecules with a spacecraft becomes like sandpaper to a match.

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A thermal protection system, or TPS, keeps a spacecraft from burning up

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when it comes back into the atmosphere on the journey home.

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Okay, so the X-33 has to be protected from the heat,

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but can TPS be used to shield something from the cold,

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like maybe a special outfit for me to wear so I won't freeze during this winter bike race?

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Yes, some are being used in down-to-earth applications

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that keep homes and people protected from temperature extremes, both hot and cold.

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Portions of the X-33 TPS systems were tested in a high-performance jet

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at the NASA Dry Flight Research Center,

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and also in special wind tunnel tests at the NASA Langley Research Center

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and at the NASA Ames Research Center.

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I guess I did a small-scale test with my one-mile bike run.

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That's right. Your one-mile test run was a much more manageable size

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to test your bike's technologies than the 25-mile race.

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Because of your testing, you'll be able to change things on the bike

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and retest more easily.

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Now, although the tests were conducted on two different types of vehicles,

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your bike and the X-33, they basically serve the same purpose.

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They use math and science concepts to overcome challenges.

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Okay, Vance, so tell me, what did you learn from your test run?

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That I was exhausted. The bike is so heavy, it was really hard to pedal up the hills.

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That's because it took an excessive amount of energy to propel the vehicle.

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If you multiply the energy that it took to go one mile times the 25 you'll need in the race,

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you can see there's a problem.

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I see what you're saying. Hey, let's figure it out mathematically.

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Okay, how can a one-mile bike ride tell us what a 25-mile bike race will require?

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Enter the world-famous ratio.

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A ratio is a way of comparing the size of two numbers.

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Let's compare Vance's one-mile test run to the 25-mile bike race he will enter.

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Now, ratios can be written in numerous ways.

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Like that.

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Or even like that.

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Now, all of these ratios are read the exact same way.

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They're all read 1 to 25.

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Ratios can also be written as a fraction. Got it?

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So, for every one of whatever it took for Vance's test ride,

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it will take 25 times that in order to complete the race.

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For example, let's say Vance has to pedal on average 1,500 revolutions to go that one mile.

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Can you estimate how many revolutions he can expect to pedal in order to complete the race?

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One way to solve this problem is to use the fraction ratio and set it up like this.

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One mile to 25 miles equals 1,500 revolutions to what?

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I mean, what number can you put here so that this second fraction equals 1 to 25?

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It's easy.

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If you multiply 25 times 1,500 revolutions, that equals...

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37,500 revolutions.

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In order for Van to complete the 25-mile bike race, he will have to pedal approximately 37,500 revolutions.

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Better him than me.

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Now, of course, there are other ways to solve this ratio.

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What method did you use?