Exchange with CoolHardLogic on geostationary satellite launches on his video # 4

p-brane:  Would you agree with the following equatorial geostationary satellite launch scenario? 

1.       You launch from the equator from west to east.

2.       You go into a circular low earth orbit, 100 to 200 miles up, at a speed of 17,500 mph and a 90 minute orbital period.

3.       Then, at the opposite side of the earth that you want to position the GEO SAT, you begin a Hohmann transfer orbit by accelerating the launch vehicle to about 23,000 mph, then coasting and slowing down due to the earth’s gravity the rest of the way up to GEO orbit about 22,236 miles up.

4.       Just as the craft reaches GEO orbit height, its speed now reduced to about 3,500 mph, fires its apogee “kick” motor, accelerating the craft to almost 7,000 mph, circularizing the orbit and synchronizing the satellite with the earth’s rotation.

Would you say that this launch scenario, give or take a few mph, is accurate?

CoolHardLogic:  Hi + p-brane

It would have helped if you'd used SI units. However, going with 320km initial orbit, I get 2.454km/s for the periapsis ΔV, and 1.477km/2 for the apoapsis ΔV, which are 5521.5mph and 3323mph, so I would say you're pretty much there.

p-brane Hi,

Being that you have “Logic” in your name, I’m going to ask you to exercise some of that logic, now.

If I ask you to fly your airplane from your runway to my runway, and I mark an X on my runway and ask you to “park” your plane on that X; could you accelerate when you get to the X to stop on the X?  NO!  You would have to “brake” and “reverse thrust” and brake some more and then maneuver your craft into position on top of the X, then stop.  Correct? 

Relative to your runway "take-off" spot, the X on my runway is FIXED.

Likewise, the geostationary satellite position in the sky is also FIXED, relative to its launch pad; correct?

So I have a question:  does it make sense to say that the satellite is ACCELERATED into its geostationary “parking spot”?

CoolHardLogic:

You forgot to say thanks for helping you with your calculations.

"could you accelerate when you get to the X to stop on the X?  NO!"
Incorrect. Accelerating doesn't mean "increasing". Acceleration is a change of velocity.

"So I have a question:  does it make sense to say that the satellite is ACCELERATED into its geostationary “parking spot”?"
Yes, see above.

p-brane

Thank you for taking the time to add your calculations and engage me in this conversation.  I appreciate it.

I’m not sure I understand your comment:  -- “Accelerating doesn’t mean ‘increasing’.  Acceleration is a change in velocity.” --

Yes, it’s a “change” in velocity, but that change is an increase in velocity.  Decelerating is also a change in velocity; but it’s a decrease in velocity.

This is a quote from a satellite person that I’m currently conversing with as it relates to “circularizing” the elliptical geostationary transfer orbit at its apogee to put the satellite into its geostationary coordinate:

“At apogee the satellite needs to be accelerated in order to catch up with its ‘parking spot’.”

Would you agree with him on this?