Sending A Rocket To The Moon! (Progress Sheet)

[shrox]

My point is that a model rocket lauched from the space station would have to reach escape velocity before it could reach the moon. I don't think that's possible. So, it doesn't matter which course it takes.

-- Roger

A multi-staged rocket might, think in ways that could work.

 

[beezwax]

The point is, I wanted to read it, you did not have to.

Funny that you would...oh nevermind.

It's hard to know what something is until you read it, no? Such as the impressive display by Safari Josh overnight, which I also read. Pretty funny, in a sad and kind of pathetic way. All the f-bombs and other insults would lead one to conclude that he is 20 going on 2. But it certainly wrapped up the earlier debate-- child prodigy? Half right.

 

[GDJ]

I for one hope that he continues his project. I would be elated if he just breaks the altitude record, let alone goes orbital.
His goals might have been insane, but the spirit of his project was the same as ours.

 

[jadebox]

A multi-staged rocket might, think in ways that could work.

It requires a speed of about 11,000 mph to leave earth orbit and reach a Lagrange point. That's about 5000 m/s.

Assume a fictional maximum G motor (160 Ns) with a 10 second thrust duration. Average thrust would be 16 N. The mass would be about 70 g (0.070 Kg).

F = ma

a = f / m

a = 16 N / 0.070 Kg

a = 228.6 m / s / s

v = at

v = 228.6 m / s / s * 10 s

v = 2286 m / s

Since 2286 < 5000 it can't be done with a model rocket.

Note that I based the mass on just the weight of the propellant in a G motor. The real mass of the rocket and motor would be larger which would result in a lower final speed at burnout.

-- Roger

 

[shrox]

It requires a speed of about 11,000 mph to leave earth orbit and reach a Lagrange point. That's about 5000 m/s.

Assume a fictional maximum G motor (160 Ns) with a 10 second thrust duration. Average thrust would be 16 N. The mass would be about 70 g (0.70 Kg).

F = ma

a = f / m

a = 16 N / 0.70 Kg

a = 228.6 m / s / s

v = at

v = 228.6 m / s / s * 10 s

v = 2286 m / s

Since 2286 < 5000 it can't be done with a model rocket.

Note that I based the mass on just the weight of the propellant in a G motor. The real mass of the rocket and motor would be larger which would result in a lower final speed at burnout.

-- Roger

OK.

 

[shrox]

It requires a speed of about 11,000 mph to leave earth orbit and reach a Lagrange point. That's about 5000 m/s.

Assume a fictional maximum G motor (160 Ns) with a 10 second thrust duration. Average thrust would be 16 N. The mass would be about 70 g (0.070 Kg).

F = ma

a = f / m

a = 16 N / 0.070 Kg

a = 228.6 m / s / s

v = at

v = 228.6 m / s / s * 10 s

v = 2286 m / s

Since 2286 < 5000 it can't be done with a model rocket.

Note that I based the mass on just the weight of the propellant in a G motor. The real mass of the rocket and motor would be larger which would result in a lower final speed at burnout.

-- Roger

Doh! I meant a slingshot course, I had said spiral earlier...

 

[chadrog]

Sure wish I could've got that death-ray.

 

[dlazarus6660]

Are we there yet?

 

[jadebox]

Doh! I meant a slingshot course, I had said spiral earlier...

That's what I was describing. "Slingshots" are used to change direction without using as much fuel. But, there's no magic way to escape earth without accelerating to escape velocity (speed) through firing the rocket motor.

 

[shrox]

That's what I was describing. "Slingshots" are used to change direction without using as much fuel. But, there's no magic way to escape earth without accelerating to escape velocity (speed) through firing the rocket motor.

Multi-stage HPR. 12 stages of X motors. It's still a model, I think...but if it reaches the moon, is it still a model rocket?

 

[jadebox]

Multi-stage HPR. 12 stages of X motors. It's still a model, I think...but if it reaches the moon, is it still a model rocket?

I was using the standard definition of "model rocket" which is limited to a G motor.

I'm not sure if our rockets have a high enough specific impulse to escape earth orbit.


-- Roger

 

[shrox]

I was using the standard definition of "model rocket" which is limited to a G motor.

-- Roger

Working with what we got then, how many G motors, fired at what times could make it to the moon within six months to one year on a sling shot course?

Launched for ISS or from geosynchronous orbit, whichever works. We'll assume just gyroscopic orientation, no fancy thrusters.

How many HPR to do the same?

Show your work, this goes down on your permanent record...so I can cheat off it later.

 

[luke strawwalker]

That's what I was describing. "Slingshots" are used to change direction without using as much fuel. But, there's no magic way to escape earth without accelerating to escape velocity (speed) through firing the rocket motor.

Well, there's the so-called "gravitational keyholes" or the "interplanetary superhighway" which minimizes the energy necessary to travel between planets, BUT, the energy requirements to get to them are nearly the same as that required to do the direct escape or direct injection on whatever trajectory you desire anyway...

There is, in the end after all, no such thing as a free launch...

Later! OL JR

 

[dlazarus6660]

Multi-stage HPR. 12 stages of X motors. It's still a model, I think...but if it reaches the moon, is it still a model rocket?

Yes, a model 'moon' rocket! Funny how that works.

 

[jadebox]

Well, there's the so-called "gravitational keyholes" or the "interplanetary superhighway" which minimizes the energy necessary to travel between planets, BUT, the energy requirements to get to them are nearly the same as that required to do the direct escape or direct injection on whatever trajectory you desire anyway...

There is, in the end after all, no such thing as a free launch...

Yep ... as I mentioned before, some of the moon probes have used a long, indirect route that requires much less energy because it allows them to basically fall into orbit around the moon. But, the route requires the spacecraft to reach a Lagrange point first ... which requires either enough speed (or continuous thrust) to escape earth orbit.

-- Roger

 

[Nathan]

I once tried to launch a Big Bertha to the moon. It came up short by 238,899 miles, 4,780 feet. Next time I'll try a D engine.

 

[gdiscenza]

I once tried to launch a Big Bertha to the moon. It came up short by 238,899 miles, 4,780 feet. Next time I'll try a D engine.

Maybe you could try a *very* full G?

Troj will explain the reference

G.D.

 

[Peartree]

I was thinking along the lines of getting a model rocket to the ISS, released out the airlock and "sailed" to one of the LaGrange points via a small solar sail (tested successfully last year). Depending on the size of the sail, it would take a few years (or decades) but once there, you could point it wherever you wanted.

I think those solar sails are going to be just the ticket for those people who want to have their ashes launched into the sun. It would take a long time to get there, but since they're already dead, what's the rush?

 

[shrox]

I was thinking along the lines of getting a model rocket to the ISS, released out the airlock and "sailed" to one of the LaGrange points via a small solar sail (tested successfully last year). Depending on the size of the sail, it would take a few years (or decades) but once there, you could point it wherever you wanted.

I think those solar sails are going to be just the ticket for those people who want to have their ashes launched into the sun. It would take a long time to get there, but since they're already dead, what's the rush?

Now you're thinking in ways that could work!

 

[dave carver]

I think those solar sails are going to be just the ticket for those people who want to have their ashes launched into the sun. It would take a long time to get there, but since they're already dead, what's the rush?

Won't work, John. Solar sails work going "downstream". It would take some fancy sailing to tack towards the sun and you would never be able to reach the sun unless you could get close enough for gravity to take over. Due to the radial nature of the solar winds it just wouldn't work.

 

[SteveA]

Solar sails work going "downstream".

It would work for what I would want though. Sending my ashes into the sun seems..redundant. Me, I would want to be launched out of the solar system and at some point my ashes be jettisoned so that they would float into deep space...or to what ever else they encountered.:eyepop:

 

[Mushtang]

Why send ashes? I'd rather be sent frozen, like Frank Poole, into an orbit around the sun. Preferably it'll be before I die of some disease that we can't cure and then someday a few thousand years from now I can be reawakened, cured, and live in the future.

 

[WillMarchant]

Won't work, John. Solar sails work going "downstream". It would take some fancy sailing to tack towards the sun and you would never be able to reach the sun unless you could get close enough for gravity to take over. Due to the radial nature of the solar winds it just wouldn't work.

Depending upon the attitude you can add or subtract orbital energy which will raise or lower the perihelion. https://en.wikipedia.org/wiki/Solar_sail has a more elegant explanation.

 

[Peartree]

Won't work, John. Solar sails work going "downstream". It would take some fancy sailing to tack towards the sun and you would never be able to reach the sun unless you could get close enough for gravity to take over. Due to the radial nature of the solar winds it just wouldn't work.

Since NASA has plans to use them to ferry stuff to the outer rim of the solar system and back, I'm assuming that they can tack against the wind just like a sailboat. I don't know if they'd need a jib, but the guys developing them seem to think they can travel both directions.

I don't know if there is anyone thinking about such things, but if these can be built small, smart and cheap (a very tough combination) these may eventually be useful in de-orbiting space junk.

 

[beezwax]

Depending upon the attitude you can add or subtract orbital energy which will raise or lower the perihelion. https://en.wikipedia.org/wiki/Solar_sail has a more elegant explanation.

Thanks for linking the wiki article. I first read about solar sails back in the 80s, but the idea seemed an awfully long way from reality and I haven't given them any thought since then. Interesting to read about how the technology and research has continued.

 

[jadebox]

Since NASA has plans to use them to ferry stuff to the outer rim of the solar system and back, I'm assuming that they can tack against the wind just like a sailboat.

As I understand it, it's more like how spacecraft in orbit fire thrusters along the direction of travel to speed up and go to a higher orbit or against the direction of travel to slow down to enter a lower orbit.

If the sail is oriented in one direction, orbital speed of the spacecraft is increased, moving it away from the sun. Angled the other way, the sail slows the spacecraft's orbital speed, causing it to move toward the sun.

-- Roger

 

[dlazarus6660]

Why send ashes? I'd rather be sent frozen, like Frank Poole, into an orbit around the sun. Preferably it'll be before I die of some disease that we can't cure and then someday a few thousand years from now I can be reawakened, cured, and live in the future.

Good movie...Ooops wrong thread!

 

[shrox]

Since NASA has plans to use them to ferry stuff to the outer rim of the solar system and back, I'm assuming that they can tack against the wind just like a sailboat. I don't know if they'd need a jib, but the guys developing them seem to think they can travel both directions.

I don't know if there is anyone thinking about such things, but if these can be built small, smart and cheap (a very tough combination) these may eventually be useful in de-orbiting space junk.

I think the resistance of the water is a major factor, just like a tethered kite can move forward and back through the wind, but once the string breaks it moves with the wind.

The moon spends a few days "downstream" from Earth as well.

 

[dlazarus6660]

So getting back on track, didn't some guy jump out of a balloon some 24 miles up? Can't that balloon be used again to get the 'model' rocket that high then launched from there. I know it's called a rockoon and it would be a 1/4 way there to LEO before launching. Somebody should have set that up when he pulled his stunt.

 

[RodRocket]

I wonder if Orville and Wilbur got this kind of flack when they told someone they were going to invent the airplane.