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Designing our own Spacecraft


NSEP

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Hmmm steel isn't very helpful as far as mass is concerned. An alloy of aluminium is probably going to be better. Also, if this is an unmanned mission, why not make it smaller and unpressurized? Would help with  the mass issue. If you do make it pressurized, the internal pressure might help with keeping it rigid, like with (IIRC) the Atlas rockets.

Also might need to think about a heating system for the electronics. Space is cold. Electronics do not like cold.

Also a name for the craft (some idea) - Jeb's Dare 1?

1 minute ago, NSEP said:

I might come up with a parachute holding rope gizmo thing, so it at least does not rip apart from the capsule.

This might be a more materials problem rather than structure. Kevlar rope might do. Or a drogue chute so that sudden violent jerking of the vehicle doesn't rip the parachute.

Edited by qzgy
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7 minutes ago, qzgy said:

Hmmm steel isn't very helpful as far as mass is concerned. An alloy of aluminium is probably going to be better. Also, if this is an unmanned mission, why not make it smaller and unpressurized? Would help with  the mass issue. If you do make it pressurized, the internal pressure might help with keeping it rigid, like with (IIRC) the Atlas rockets.

Also might need to think about a heating system for the electronics. Space is cold. Electronics do not like cold.

Also a name for the craft (some idea) - Jeb's Dare 1?

This might be a more materials problem rather than structure. Kevlar rope might do. Or a drogue chute so that sudden violent jerking of the vehicle doesn't rip the parachute.

By making it unpressurized it would be hard to detect any leaks/holes inside the capsule and where they come from, for the future manned version. I could make it smaller, and i might do that, soon. I could use aluminum alloys instead of steel though, wich alloy does not expand as much because of heat!

I am currently thinking of a heating system, thanks for reminding me!

Yes, the drogue chutes can be used to keep things upright. Having only one parachute on a ball might make its spin or jiggle in another axis.

15 minutes ago, Ultimate Steve said:

I designed a small space capsule once. However, it was very evident I didn't know what I was doing and it was a pretty bad design, but I'll upload pictures sometime.

What were the flaws of the design, we can use the flaws to help improve the our new design.

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We'll need something to make the capsule float. If it lands in the ocean, then it'll sink...

(Unless there's a ton of air inside but with all the metal, I kind of doubt it'll float without additional support)

Edited by Earthlinger
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17 hours ago, NSEP said:

please note that i do not care about heat expansion/things cracking/things like that.

Uhh... this is a severe issue. If the skeleton cracks and breaks down, your vehicle will break and inherently become fatal. This isn't a maybe but a guarantee.

Just now, Earthlinger said:

We'll need something to make the capsule float. If it lands in the ocean, then it'll sink...

make a wide body that is sealed. Apollo was buoyant because it was a large flat body with no openings for water to enter.

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58 minutes ago, ZooNamedGames said:

Uhh... this is a severe issue. If the skeleton cracks and breaks down, your vehicle will break and inherently become fatal. This isn't a maybe but a guarantee,

I found out when the discussion started, yet i forgot to edit the page. I edited it now. Thanks.

1 hour ago, ZooNamedGames said:

make a wide body that is sealed. Apollo was buoyant because it was a large flat body with no openings for water to enter.

Hmmm, never thought of a water landing actually, i would have to redesign the capsule in order to make it shaped like the Apollo, since the current capsule is spherical. Luckily most of the capsule hasn't been fully desinged yet so its not a hard choice.

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2 minutes ago, NSEP said:

I found out when the discussion started, yet i forgot to edit the page. I edited it now. Thanks.

Hmmm, never thought of a water landing actually, i would have to redesign the capsule in order to make it shaped like the Apollo, since the current capsule is spherical. Luckily most of the capsule hasn't been fully desinged yet so its not a hard choice.

First suggestion is to find it's purpose for this vehicle. Designing a vehicle then backtracking to adjust it to a purpose generally requires more effort and changes than the alternative.

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1 hour ago, mabdi36 said:

I'll do any rocket science you need!

Okay, well i got a task for you! If we got a gasoline/gaseous oxygen rocket engine, a mixture ratio of 2.5 and a Specific Impulse of 261s, with our dry spacecraft being 9 tons. Then what would be the total mass of the propellant needed for 100m/s of Delta-V and the volume of both propellants?

Thanks for wanting to contribute! Much appreciated!

12 hours ago, dundun92 said:

As far as guidance, i reccomend an arduino or raspberry pi.

How many watts of energy the does a raspberry pi use? And at what low temperature does the raspberry stop operating? Thanks!

Edited by NSEP
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17 hours ago, NSEP said:

Okay, well i got a task for you! If we got a gasoline/gaseous oxygen rocket engine, a mixture ratio of 2.5 and a Specific Impulse of 261s, with our dry spacecraft being 9 tons. Then what would be the total mass of the propellant needed for 100m/s of Delta-V and the volume of both propellants?

Thanks for wanting to contribute! Much appreciated!

How many watts of energy the does a raspberry pi use? And at what low temperature does the raspberry stop operating? Thanks!

As in 2.5 times more gasoline than oxygen?

 

I would not suggest using Gasoline and gaseous oxygen, because:

1. Gaseous oxygen has a very low density, and conpressing it at that level would probably make the tank blow up.

2. The mixture ratio would be more like 14:1

3. NO THRUST

So, I would not use it except if you are trying to build a CAR. Instead, RP-1 with LOX is a better idea, since it creates TONS MORE THRUST and it has a specific impulse close to the one needed, is light and is versatile (unlike hydrogen). RP-1 is basically gasoline, so the only thing we need to change is gas to liquid oxygen. Only then the mixture ratio would be 1.65:1, if we use a less powerful variant of the F1 engine. Also, I need more information about how this rocket engine will be used (Lifter or orbiter) since i need to include TWR and include a thrust figure from this data.

 

At maximum, a Raspberry Pi consumes around 2 watts. Not much data about operating temps tho, but the max minimum temperature is 0•C while the lowest possible minimum is -40•C, so it isn’t very consistent.

Edited by mabdi36
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On ‎1‎/‎01‎/‎2018 at 1:31 PM, NSEP said:

My plan is to design a spacecraft capable of launching and safely returning back to Earth from orbit. And after thats done, we design a spacecraft capable of manned spaceflight and docking with stations.

I have ideas like this too, but for a slightly different setting.

On ‎1‎/‎01‎/‎2018 at 1:31 PM, NSEP said:

Our Spacecraft is not going to be heavier than 10 tons or lighter than 6 tons.

Seems a bit arbitrary. There are currently 3 space programs capable of lifting 24 or more metric tons in a single launch.

On ‎1‎/‎01‎/‎2018 at 1:31 PM, NSEP said:

- The Skeleton is going to be made out of steel bars. The steel bars are cylinders and have a diameter of 2,5cm. 1m of this steel bar masses in at 3779.669grams or 3.78kg. Now lets make a steel ring shall we? We first need to know the circumference of the ring we need, we know the radius of the capsule is one metre so 2*pi*1=6.3 metres. Now 6.3 metres times the mass per meter (3.78kg) and we have the the mass per ring, so 6.3*3.78=23.814kg. Now that we have the mass per ring, we can continue to make the skeleton. Our sphere needs, lets say, 5 rings, (4 rings longitude and 1 ring latitude).Thats 23.814*5=119.07kg. for our skeleton in total.

Rather than building a completely new crew compartment from scratch, my idea is to use a pre-existing, commercially available vessel with built-in closed-loop life support systems. In other words, build the spaceship parts around a miniature submarine or aircraft.

On ‎1‎/‎01‎/‎2018 at 1:31 PM, NSEP said:

- Avionics and most Electronics are out of my field. If anyone here knows anything about that and wants to help, feel free to join in.

Reaction wheels, transmitters, antennas, computers, batteries, solar arrays, transceivers, navigation equipment and other stuff can be aquired from cubesat harware suppliers. Although I'm not sure if equipment made for a satelite one ten-thousandth of the size of our vessel will still work.

On ‎1‎/‎01‎/‎2018 at 1:31 PM, NSEP said:

- Fuel tanks are made of steel, oh and they would carry Hydrazine Nitrogen for RCS.

- Im not a rocket engine person, so i would have to find a pre-designed Hydrazine Nitrogen RCS thruster. If anyone is willing to build their own thruster for the spacecraft, feel free to join in

I have quite a few ideas for solid, hybrid, liquid and cold-gas thruster modules. For example:

http://aeroconsystems.com/cart/liquid-motors/rocketdyne-lr64-rocket-motor/

http://www.maxentropy.net/rocketry/liquidproject/design/design.htm

http://aeroconsystems.com/cart/liquid-motors/rocketdyne-lr101-bipropellant-rocket-motor/

http://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/Bipropellant Data Sheets.pdf

http://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/Monopropellant Data Sheets.pdf

 

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7 hours ago, mabdi36 said:

As in 2.5 times more gasoline than oxygen?

 

I would not suggest using Gasoline and gaseous oxygen, because:

1. Gaseous oxygen has a very low density, and conpressing it at that level would probably make the tank blow up.

2. The mixture ratio would be more like 14:1

3. NO THRUST

So, I would not use it except if you are trying to build a CAR. Instead, RP-1 with LOX is a better idea, since it creates TONS MORE THRUST and it has a specific impulse close to the one needed, is light and is versatile (unlike hydrogen). RP-1 is basically gasoline, so the only thing we need to change is gas to liquid oxygen. Only then the mixture ratio would be 1.65:1, if we use a less powerful variant of the F1 engine. Also, I need more information about how this rocket engine will be used (Lifter or orbiter) since i need to include TWR and include a thrust figure from this data.

 

At maximum, a Raspberry Pi consumes around 2 watts. Not much data about operating temps tho, but the max minimum temperature is 0•C while the lowest possible minimum is -40•C, so it isn’t very consistent.

The mixture ratio is 2.5! 2.5x more Gaseus oxygen. I We use Gasoline because high thrust is not our main concern. All you need to do is get back down from orbit, this does not require any high amounts of thrust, neither do you need loadsof Delta-V. We are not trying to take of from the ground.

Read this page:

https://risacher.org/rocket/propellant.html

Edited by NSEP
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6 hours ago, ChrisSpace said:

I have ideas like this too, but for a slightly different setting.

Seems a bit arbitrary. There are currently 3 space programs capable of lifting 24 or more metric tons in a single launch.

Rather than building a completely new crew compartment from scratch, my idea is to use a pre-existing, commercially available vessel with built-in closed-loop life support systems. In other words, build the spaceship parts around a miniature submarine or aircraft.

Reaction wheels, transmitters, antennas, computers, batteries, solar arrays, transceivers, navigation equipment and other stuff can be aquired from cubesat harware suppliers. Although I'm not sure if equipment made for a satelite one ten-thousandth of the size of our vessel will still work.

I have quite a few ideas for solid, hybrid, liquid and cold-gas thruster modules. For example:

http://aeroconsystems.com/cart/liquid-motors/rocketdyne-lr64-rocket-motor/

http://www.maxentropy.net/rocketry/liquidproject/design/design.htm

http://aeroconsystems.com/cart/liquid-motors/rocketdyne-lr101-bipropellant-rocket-motor/

http://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/Bipropellant Data Sheets.pdf

http://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/Monopropellant Data Sheets.pdf

If you have ideas, please tell us!

24 tons is way too high for a spacecraft of the type we are trying to build.

So you mean only the crew section of a submarine or should we cover the sub in heatshielding? Our space capsule has to be space capsule shaped. I apologize for my misunderstanding.

Thanks for the engine/electronic suggestions! Very much appreciated!

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1 hour ago, NSEP said:

The mixture ratio is 2.5! 2.5x more Gaseus oxygen. I We use Gasoline because high thrust is not our main concern. All you need to do is get back down from orbit, this does not require any high amounts of thrust, neither do you need loadsof Delta-V. We are not trying to take of from the ground.

Read this page:

https://risacher.org/rocket/propellant.html

oops

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14 minutes ago, NSEP said:

Thanks for doing the math pal!

I might as well scale the maximum mass up a notch. 13t is not extremely heavy. 

THAT IS NOT HOW SCALING UP WORLKS. If you want to scale up, ask, as it is not linear

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10 minutes ago, mabdi36 said:

THAT IS NOT HOW SCALING UP WORLKS. If you want to scale up, ask, as it is not linear

I meant bring up the total mass budget, the current total mass budget is 10tons. 

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@mabdi36, There is a slight error in your calculation. I gave you the specific impulse of the engine, but your formula uses the exhaust velocity instead of the specific impulse. This is a common mistake however. 

To calculate the Exhaust velocity, use this formula:

Ve = 9.8*Isp

I will try calculating it myself later, thanks!

 

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17 hours ago, NSEP said:

If you have ideas, please tell us!

All the cubsat stuff I mentioned can be found here: https://www.cubesatshop.com/ https://www.clyde.space/products

You can find anything from cameras to decouplers to the stuff I mentioned earlier there.

As for landing, we could get a bit more creative than simple parachutes. A deployable hang glider could glide the capsule down onto a runway, for example.

As for propulsion, there are a wide range of interesting tricks that can be done. For example, the "rocket" part of an RPG-7 provides about 338.9N of thrust for 2.39 seconds, so it could be used for stage separations, for example (remember to take the explodey bit out first). Another idea is to make a "rocket candy" engine, which could potentially have an Isp of up to around 125s. Or we could go with commercially-available SRBs, which can surpass 6kN in some cases. Or we could do what these guys did to make an 8kN engine: http://ddeville.com/derek/CSXT.htm or what Copenhagen Suborbitals is doing for it's space program.

Regarding safety, an ejector seat could be used to get the pilot to a safe distance in the event of an emergency during liftoff or landing.

From here onwards my ideas start to become more speculative...

18 hours ago, NSEP said:

So you mean only the crew section of a submarine or should we cover the sub in heatshielding? Our space capsule has to be space capsule shaped. I apologize for my misunderstanding.

Miniature submarines and ultralight aircraft come in many different shapes, and while we'd obviously remove propellers and other air/sea stuff we don't need, the rest can stay intact. Just cover it with sheet metal and Aluminum, or some other cheap metal.

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