Getting to space for only pennies! Low Budget Space Program

[_Augustus_]

This is a really good idea, unfortunately it's questionable how far you'll get. You need a verrry big version of what you're currently making to get anywhere near space.

Also, I know that other people have posted this, but couldn't the FAA put you in prison if you do succeed?

[ChrisSpace]

Camera is a luxury. Expensive luxury. This is about kitchen rocketry with high chance of the payload not surviving. I wouldn't risk my camera unless there was a history of successful launches and recoveries.

What, so we are just going to look at a blip on a screen, or a number getting higher and higher, instead of actually recording the view from up there? A camera would make the final result much more pleasing and would give more of a sense of accomplishment. And space-grade cameras are not even that expensive or massive.

UpsilonAerospace mentioned a balloon + 2 stages to just barely reach space - I don't have any figures, but I wouldn't imagine the rocket itself is going to be in the region of multiple hundreds of kg, which I would consider "heavy".

You do not seem to understand how heavy our suborbital rocket will have to be. even reaching space requires 2-3km/s of Dv, and for comparison the Dv required for orbit is 9km/s, so this is no estes firework rocket here. We are talking about something weighing around 1-2 metric tons if we are launching it from a balloon, and more if we are launching it from the ground. If we go for a balloon launch, granted, the rocket itself would be smaller, however the balloon would need to carry enough helium to produce enough buoyancy to lift our two-ton rocket, so the final vehicle would actually be larger, and certainly more complex.

The balloon drifting off is an issue how, exactly? Assuming you go with the simple and stupid route, you're not going to have anything remotely controlled, so distance from ground control should not be an issue. Lets be realistic - if you really want to reach space, is 50 km of balloon drift going to matter in the end? You are most likely not recovering that payload anyway (assuming it even survives).

We will need to keep a line of sight with ground control to maintain communications, plus we don't want our rocket reentering over, and crashing into, a populated area.

[Deutherius]

What, so we are just going to look at a blip on a screen, or a number getting higher and higher, instead of actually recording the view from up there? A camera would make the final result much more pleasing and would give more of a sense of accomplishment. And space-grade cameras are not even that expensive or massive.

You can buy and add one if you want to, nobody is forcing you not to. It's not necessary to the goal, however, so I would omit it.

You do not seem to understand how heavy our suborbital rocket will have to be. even reaching space requires 2-3km/s of Dv, and for comparison the Dv required for orbit is 9km/s, so this is no estes firework rocket here. We are talking about something weighing around 1-2 metric tons if we are launching it from a balloon, and more if we are launching it from the ground. If we go for a balloon launch, granted, the rocket itself would be smaller, however the balloon would need to carry enough helium to produce enough buoyancy to lift our two-ton rocket, so the final vehicle would actually be larger, and certainly more complex.

Alright, since nobody is giving me any figures, I'm going to attempt some very rough and wild 10 minute napkin math. Assuming an Isp of about 115 seconds, a maximum wet/dry mass ratio of ~3:1 (a very wild guess, feel free to correct me), a goal of 2500 m/s deltaV, and a stage deltaV distribution as 1000 m/s for booster stage and 1500 m/s for sustainer stage. If you can manage to make your dry mass of sustainer stage 20 kg, your sustainer stage wet mass will be ~95.6 kg, and to get 1000 m/s with this Isp you have to make your wet/dry booster mass ratio of about 1:1. We are talking about 232 kg of full wet mass of the entire assembly minus booster stage body. An estimate would be that if we can build a 20 kg body for 75.6 kg of fuel, we could build a 62 kg body for the entire assembly we have so far. I'll go wild and say the booster stage body is 100 kg, just for that extra structural integrity. That puts me at ~474.5 kg full wet mass. These figures go down when you decrease the sustainer stage dry mass, of course (~170 kg full wet mass for a sustainer dry mass of 10 kg. ~70 kg full wet mass for a 5 kg dry sustainer mass. And so on.)

<edit>Now that I read it after myself again - I meant a fuel to not-fuel ratio with that "wet/dry". 3 parts fuel to 1 part the other stuff (hull, engine, fins, staging...). Same with booster stage, 1:1 meaning 1 part is fuel and 1 part is sustainer stage + booster hull. Should be a propellant mass ratio of ~0.74 for the sustainer stage and ~0.6 for the booster stage.</edit>

Granted, there is a lot of assumptions, but at least it's some actual numbers (I'd be happy to hear the real figures and why I'm wrong, if I am wrong). I'll be the first one to admit that it's a lot more than I estimated, but it's nowhere near the 1-2 metric tons you are describing (that would require a sustainer dry mass of around 100 kg by my calculations).

I also now have an image in my head of someone trying to cook a 400 kg batch of rocket candy. What could go wrong?

We will need to keep a line of sight with ground control to maintain communications, plus we don't want our rocket reentering over, and crashing into, a populated area.

What exactly do you mean by "communications" that need direct LOS? There is nothing I can think of that cannot be made automated and/or sent/retrieved via a satellite link.

The second part, I agree, that is a very good reason.

Edited April 21, 2015 by Deutherius
added part for clarification

[mardlamock]

It would have to be a motor with fins, I can build a pretty decent motor with 900m/s of delta v, wet mass 1.5kg, dry mass 0.5kg, so I guess you could do with that. 4 stages would just about give you enough delta v to make it into space.

[Bill Phil]

It would have to be a motor with fins, I can build a pretty decent motor with 900m/s of delta v, wet mass 1.5kg, dry mass 0.5kg, so I guess you could do with that. 4 stages would just about give you enough delta v to make it into space.

Delta V doesn't scale like that... Sadly

[Neil1993]

It would have to be a motor with fins, I can build a pretty decent motor with 900m/s of delta v, wet mass 1.5kg, dry mass 0.5kg, so I guess you could do with that. 4 stages would just about give you enough delta v to make it into space.

It's generally not a very good idea to use more than 3 stages on rockets without active control (from experience). It almost always results in the rocket going off course, which is something the FAA definitely wouldn't be very happy about.

[mardlamock]

Delta V doesn't scale like that... Sadly

I know, but I did the math and it does work. gives about 1600m/s of dv, launching from a balloon thats more than enough. With 5 stages you get 2000m/s of delta V, so you could do with a camera.

- - - Updated - - -

It's generally not a very good idea to use more than 3 stages on rockets without active control (from experience). It almost always results in the rocket going off course, which is something the FAA definitely wouldn't be very happy about.

That depends alot on the rocket itself and its initial acceleration, the first stage should have a good TWR and it should be spin stabilized (Like most rockets this size). It would be like 2,5 meters tall and could probably have diameter as small as (or 5 if you really want to minimize drag losses).

[Neil1993]

That depends alot on the rocket itself and its initial acceleration, the first stage should have a good TWR and it should be spin stabilized (Like most rockets this size). It would be like 2,5 meters tall and could probably have diameter as small as (or 5 if you really want to minimize drag losses).

Not always. High winds (like those encountered at higher altitudes) will still push the rocket around. And the real problem is the ignition of UNRELIABLE, AMATEUR-MADE, rocket motors (if we're being specific to the project here). Material ejecting from the motor or thrust that isn't perfectly aligned on the longitudinal axis (These are some very common problems with these kinds of motors. Again, from experience) at motor start could cause significant path deviation.

[mardlamock]

Not always. High winds (like those encountered at higher altitudes) will still push the rocket around. And the real problem is the ignition of UNRELIABLE, AMATEUR-MADE, rocket motors (if we're being specific to the project here). Material ejecting from the motor or thrust that isn't perfectly aligned on the longitudinal axis (These are some very common problems with these kinds of motors. Again, from experience) at motor start could cause significant path deviation.

Of course there would be path deviations, but I dont really think they would be as large as you say. The trickiest ignition would be the first one, the rest would be so hard as you could just expose the pyrogen of the next stage as the earlier finishes its burn. The motors I am talking about last 1.5ish seconds each, so the total burn time wouldnt be all that long. OP doesnt have the building skills IMO to build such a motor, but someone experienced might. May I ask, what class were the motors you built in?

[Neil1993]

Of course there would be path deviations, but I dont really think they would be as large as you say. The trickiest ignition would be the first one, the rest would be so hard as you could just expose the pyrogen of the next stage as the earlier finishes its burn. The motors I am talking about last 1.5ish seconds each, so the total burn time wouldnt be all that long. OP doesnt have the building skills IMO to build such a motor, but someone experienced might. May I ask, what class were the motors you built in?

First few were G to I (-ish). The last I built with some colleagues and it was close to M. In the near future, I'll be doing analysis of parts for hybrid and solid motors on sub-orbital sounding rockets, but overall, I prefer working on air-breathing propulsion. I was thinking of path deviations in terms of OP's potential sugar motors too. A professional motor with APCP would be more reliable but would require an electrical ignition system.

[mardlamock]

First few were G to I (-ish). The last I built with some colleagues and it was close to M. In the near future, I'll be doing analysis of parts for hybrid and solid motors on sub-orbital sounding rockets, but overall, I prefer working on air-breathing propulsion. I was thinking of path deviations in terms of OP's potential sugar motors too. A professional motor with APCP would be more reliable but would require an electrical ignition system.

Cool, I ve only built up to J-K class, but completly on my own. I cant really test anything larger here. Electrical ignition is a must for the first stage, that would be tricky, but not impossible. APCP would make this waay more feasible, 3 stages or even less. Im sure most of you have already seen this rocket, but OP's would have to be like 4 of them stacked up ontop of each other.

(its ridiculous, i know)

[Neil1993]

Im sure most of you have already seen this rocket, but OP's would have to be like 4 of them stacked up ontop of each other.

(its ridiculous, i know)

I don't think cardboard would hold up under that kind of acceleration. XD

I would seriously recommend that the OP take a gander back to the drawing board. A considerable amount of research would serve him well.

[Bill Phil]

Are these motors entirely custom built?

Can you, OP, build a nozzle?

If so, then experiment with different expansion ratios.

[LowBudgetSpaceProgram]

We are currently testing different nozzles and we are getting surprising results. We machine them on a lathe, that way they are as symetrical as we can possibily make them. There is a metal shop close by and they were interested in making nozzles for us. I'll have a video up soon showing what happens if you put the wrong nozzle on a motor!

[ChrisSpace]

Alright, since nobody is giving me any figures, I'm going to attempt some very rough and wild 10 minute napkin math. Assuming an Isp of about 115 seconds, a maximum wet/dry mass ratio of ~3:1 (a very wild guess, feel free to correct me), a goal of 2500 m/s deltaV, and a stage deltaV distribution as 1000 m/s for booster stage and 1500 m/s for sustainer stage. If you can manage to make your dry mass of sustainer stage 20 kg, your sustainer stage wet mass will be ~95.6 kg, and to get 1000 m/s with this Isp you have to make your wet/dry booster mass ratio of about 1:1. We are talking about 232 kg of full wet mass of the entire assembly minus booster stage body. An estimate would be that if we can build a 20 kg body for 75.6 kg of fuel, we could build a 62 kg body for the entire assembly we have so far. I'll go wild and say the booster stage body is 100 kg, just for that extra structural integrity. That puts me at ~474.5 kg full wet mass. These figures go down when you decrease the sustainer stage dry mass, of course (~170 kg full wet mass for a sustainer dry mass of 10 kg. ~70 kg full wet mass for a 5 kg dry sustainer mass. And so on.)

< edit>Now that I read it after myself again - I meant a fuel to not-fuel ratio with that "wet/dry". 3 parts fuel to 1 part the other stuff (hull, engine, fins, staging...). Same with booster stage, 1:1 meaning 1 part is fuel and 1 part is sustainer stage + booster hull. Should be a propellant mass ratio of ~0.74 for the sustainer stage and ~0.6 for the booster stage.</edit>

Granted, there is a lot of assumptions, but at least it's some actual numbers (I'd be happy to hear the real figures and why I'm wrong, if I am wrong). I'll be the first one to admit that it's a lot more than I estimated, but it's nowhere near the 1-2 metric tons you are describing (that would require a sustainer dry mass of around 100 kg by my calculations).

I will admit that my 1-2 tons figure was a random estimate. Anyways, how do these figures compare with what LBSP is planning?

[Deutherius]

I will admit that my 1-2 tons figure was a random estimate. Anyways, how do these figures compare with what LBSP is planning?

I cannot possibly answer that question since I have no clue what LBSP is planning As far as I know, this balloon idea was considered by UpsilonAerospace, who seemed to have things figured out already - you could ask him.

LBSP is currently testing nozzles, so I doubt he/she/they is/are planning something of this scale just yet

[LowBudgetSpaceProgram]

I cannot possibly answer that question since I have no clue what LBSP is planning As far as I know, this balloon idea was considered by UpsilonAerospace, who seemed to have things figured out already - you could ask him.

LBSP is currently testing nozzles, so I doubt he/she/they is/are planning something of this scale just yet

Yes everything is theoretical right now and we are starting small with the basics before we move on. This is how we can get a lot done while still being safe!

[ChrisSpace]

Any progress?

[ChrisSpace]

Nothing?

[Kruleworld]

I am a part of the Low Budget Space Program.

You remind me of the guys on 'Rocket City Rednecks'

still, i admire your adventurousness.

[ChrisSpace]

No news? Is the party over?