For millennia the cats of Catalonia had looked up at the sky and longed to catch the dots of light sprinkled across it. Even as their civilization advanced and they discovered the true nature of those bright dots, their yearning to reach them never faltered. In time, that desire became a point of contention between Catalonia’s two dominant nations.
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Unfortunately, ideological differences aren’t confined to humanity. The countries of Felinia and Catstroph became bitter rivals as each tried to advance their views on proper scratching post materials. For Felinia, using anything other than cardboard was considered an affront to all cats, while Catstroph claimed a scratching post not made of carpet to be an abomination. Sure that being the first to get a cat into space would be a propaganda bonanza, each nation worked feverishly (between cat naps of course) to achieve this goal.
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Felinia was the first to have a rocket ready for launch. The nation’s most decorated military test pilot, Major Thomas Fluffison (his friends call him Tom), was selected to be its pilot. There was great rejoicing throughout the nation (parades with catnip confetti and milk fountains) as the day of launch drew closer.
However, the leaders of Catstroph weren’t about to give up that easily. They’d already prepared plans in the event their rocket wasn’t ready in time. The night before the launch, even though security was tight, a small orange kitten slipped into the launch area. Soundlessly, he made his way up the stairs and stopped at a small electrical panel on the rocket. Carefully, he opened it. Slipping on some rubber gloves, he proceeded to loosen several wires until they were barely held in place. Closing the panel, he purred to himself. That should take case of Major Tom. Within a few minutes, he disappeared as soundlessly as he came.
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There was great fanfare as Major Tom made his way into the rocket. He shook paws with Felinia’s leaders and held up the cardboard scratching post he’d be taking into space with him. Technicians strapped him into the capsule’s chair and sealed the door as they left. Going through his checklist with ground control, everything looked good.
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“… 5, 4, 3, 2, 1, ignition,” called the launch controller as the rocket’s engine roared to life, engulfing the launch pad with fire and smoke. The rocket rose majestically into the sky and slowly arced towards the horizon and was soon out of sight as ground control radioed. “Catspeed Major Tom. Good luck.”
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As the rocket accelerated upward, our catronaut was pushed back into his chair and could hardly move. It was all he could do to keep his eyes on the instrument panel. His heart leaped as a red light began to flash and an alarm blared: the rocket engine had malfunctioned. “Ground control to Major Tom,” came the urgent call. “Attempt engine restart.”
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“Negative on restart,” radioed Major Tom, now able to move freely. “Going for early stage 2 ignition.”
“There won’t be enough fuel …” came the reply.
If you discover this tale on Amazon, be aware that it has been stolen. Please report the violation.
Major Tom cut it off. “It’s either that or crash.” Without waiting for an answer, he activated the stage separation system and immediately ignited the stage 2 engine. The rocket shook and once again he was pushed back into the chair as his rocket continued its journey into space.
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Ten minutes later, he was in orbit. It wasn’t as high an orbit as planned, but it was stable. There was only one problem: igniting the stage 2 engine early had used up too much fuel. There wasn’t enough left to safely return to Catalonia.
“Safely in orbit,” he radioed.
“Fuel levels?”
“Not enough.”
“We’ll do everything we can.”
Major Tom watched the planet below as he orbited. No other cat had ever seen it this way. The green land and blue oceans with a mix of white clouds was the most beautiful thing he’d ever seen. Even if this ends up being a one-way trip, he thought, this view is worth it.
Is there anything that can be done to save our fearless catronaut? The answer to that question will have to wait till our next exciting installment of Rocket Cat.
Did you notice that the rocket in today’s story didn’t go straight up, but curved toward the horizon before reaching orbit? Wouldn’t going straight up have been quicker? Sure you’d get into space faster, but you wouldn’t stay there. There’s something you need to get into orbit that you can’t get by going straight up.
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If an object’s orbiting a planet, isn’t it moving parallel to the planet’s surface? If a rocket’s going to put something in orbit, won’t it eventually have to be pointing that way? Of course, it’s not quite that simple so let’s break it down.
Image you have a football and you keep throwing it straight ahead harder and harder. What happens? It lands further and further away. The thing is, it will always take the exact same of amount of time to hit the ground. The football only travels farther because it’s moving faster.
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Now if the Earth were an infinitely long flat surface, the football would keep hitting the ground. However, the Earth is round (flat Earthers be gone) so if you threw the football hard enough it would still fall, but it’d never hit the ground because the ground is curving away beneath it. The football would be in orbit (and you’d make millions as an NFL quarterback).
Okay, so how fast does the football have to be going so it doesn’t hit the ground? To figure that out we first must consider the concept of inertia. You know, that whole if you’re in motion, you stay in motion thing. Think back to our story. Major Tom was sitting still, but the rocket was moving forward so inertia pushed him back into his chair. Physicists call what Major Tom experienced an inertial, or fictitious force.
Now what does inertia have to do with orbits? Plenty. Remember you threw the football straight ahead so its inertia wants it to continue to move that way. This inertial force acts in the opposite direction to gravity and is called a centrifugal force.
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Be warned, never confuse centrifugal with centripetal force or physicists will glare at you and make fun of your clothes. Centripetal force is what causes an object to move in a circular path (gravity for the football in our example) and acts towards the center of the circle.
Calculating centrifugal force is not for the faint of heart. To find it one must journey through the land of rotating reference frames and battle the mythical cross product (it is a fictitious force after all!).
So an object in orbit has two forces acting on it, gravity and centrifugal force. For a stable orbit, these forces must be the same. Be warned. The following picture contains mathematical equations. If interested you'll find the equations for the gravitational and centrufugal forces in the following picture. For complete disclosure, know that M is the mass of the planet, m is the mass of the capsule, r is the orbital radius, and G is the super secret gravitational constant.
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Using the information shown above you can calculate how fast the capsule has to be moving to remain in orbit. Sorry, can't resist just a bit of math here. Just look at that mathematical manipulation, it’s a thing of beauty. (Actually I had to ask my cat for some help).
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For everything we had to do to get here, the actual equation turns out to be fairly simple. The velocity shown above is only valid for a circular orbit. For an elliptical (oval) orbit, the velocity calculation is more complicated since the velocity changes as you move around the orbit.
Using the above equation, we can figure out the velocity our catronaut must have to achieve orbit. Grabbing the nearest calculator and after much typing we get an orbital velocity of 7812 m/s or 17500 mph (zoom!).
Considering how difficult it is to get something into orbit (even without cute kitten saboteurs), it’s a testament to human ingenuity that we’re able to accomplish this on a fairly regular basis. Hopefully, the cats of Catalonia also have similar resourcefulness if they’re going to bring Major Tom home safely.