Bargain bin rocket parts

[BruceJohnJennerLawso]

I almost feel like this question is better suited to the maniacs over at the KSP forums, but anyways here goes.

If I wanted to build a launcher, nonreuseable, and I wanted to use the cheapest parts I could find, what would they be, specifically in terms of engines & boosters?

 

[Urwumpe]

If I wanted to build a launcher, nonreuseable, and I wanted to use the cheapest parts I could find, what would they be, specifically in terms of engines & boosters?

Depends on your definition of cheapest: Lowest TOC? Lowest R&D for each part? Lowest purchasing costs? Lowest CO2 footprint (sorry, couldn't resist :lol?

But this would be better suited into the Physics section I think.

 

[BruceJohnJennerLawso]

Depends on your definition of cheapest: Lowest TOC? Lowest R&D for each part? Lowest purchasing costs? Lowest CO2 footprint (sorry, couldn't resist :lol?

But this would be better suited into the Physics section I think.

I dont mind moving to physics section if necessary.

Could you define TOC for me? I was thinking of preexisting if possible, so no R&D, but for all I care, the LOX/LH2 engines could be made of cast iron, so long as theyre cheap. Specifically, I was thinking low purchase cost, as reusability is not part of the plan.

 

[Urwumpe]

I dont mind moving to physics section if necessary.

Could you define TOC for me? I was thinking of preexisting if possible, so no R&D, but for all I care, the LOX/LH2 engines could be made of cast iron, so long as theyre cheap. Specifically, I was thinking low purchase cost, as reusability is not part of the plan.

Total Cost of Ownership or TCO (sorry, typo). Essentially all costs from buying it, installing it in your rocket, launching it and later disposing it.

LH2 and LOX would be way out of your range, even the cheapest ones, which likely is the RD-10 family, are very expensive. You can for example not use cast iron for this - it would corrode away and react with both hot oxygen and hot hydrogen. You need rare alloys for such machines.

If you want preexisting, you would better go by using:

- obsolete ballistic missile stages or
- solid rocket motors

While buying parts for a custom liquid rocket stage must not be really expensive, you need a lot of machinery and R&D for building the stage.

Solid rocket motors for sounding rockets can be acquired with pretty low costs compared to alternatives and are not automatically small.

Problem will of course be the bureaucracy... but well, you didn't ask for legal sources or simple acquisition process.

 

[garyw]

What are we talking about here? estes rockets? Former Saturn V's?!

A bit more detail would help.

 

[BruceJohnJennerLawso]

Total Cost of Ownership or TCO (sorry, typo). Essentially all costs from buying it, installing it in your rocket, launching it and later disposing it.

LH2 and LOX would be way out of your range, even the cheapest ones, which likely is the RD-10 family, are very expensive. You can for example not use cast iron for this - it would corrode away and react with both hot oxygen and hot hydrogen. You need rare alloys for such machines.

If you want preexisting, you would better go by using:

- obsolete ballistic missile stages or
- solid rocket motors

While buying parts for a custom liquid rocket stage must not be really expensive, you need a lot of machinery and R&D for building the stage.

Solid rocket motors for sounding rockets can be acquired with pretty low costs compared to alternatives and are not automatically small.

Problem will of course be the bureaucracy... but well, you didn't ask for legal sources or simple acquisition process.

Umm, the cast iron reference was just a joke... :lol:

anyways, I like the obsolete ICBM boosters idea, but how long would the supply last if I used, say 4 a launch? Could you maybe provide some examples of outdated CBM stages or sounding rockets? pictures would be good.

What alternatives could be cheaper than LOX/LH2? I cant see building a whole launch vehicle out of SRBs happening, so Ill need some sort of liquid fueled stage in the design.

 

[Hlynkacg]

What are we talking about here? estes rockets? Former Saturn V's?!

A bit more detail would help.

Agreed...

I mean you could build some pretty serious in your garage out stuff picked up from any industrial supply company.

...But if you're trying to get to orbit?

Well that gets a bit more complex, In "Civilized Countries" the biggest obsticals will be legal ones as governments tend to frown upon private ownership of ICBMs. There's also the command/control aspect of how do you maintain contact with your rocket when it's over the horizon?

Depending on the route you take the space craft itself may be the "cheap" part.

 

[BruceJohnJennerLawso]

Agreed...

I mean you could build some pretty serious in your garage out stuff picked up from any industrial supply company.

...But if you're trying to get to orbit?

Well that gets a bit more complex, In "Civilized Countries" the biggest obsticals will be legal ones as governments tend to frown upon private ownership of ICBMs. There's also the command/control aspect of how do you maintain contact with your rocket when it's over the horizon?

Depending on the route you take the space craft itself may be the "cheap" part.

Clarification here:

This is concept work for an Orbiter addon, not me trying to buy discount cold war ICBMs. I guess it wasnt really apparent until now :lol:

 

[Hlynkacg]

Ahhh, well ok then.

Miscommunication aside, what kind of performance are you looking for?

 

[BruceJohnJennerLawso]

Ahhh, well ok then.

Miscommunication aside, what kind of performance are you looking for?

Well, my current project created the need for this, as a shuttle D requires a really, really long launch fairing. I couldnt even fit it inside of the old side mount quasar, so I ended up having to use custom fairings on a Themis A launcher. The downside to that was that I could only get partway to orbital velocity on the themis, and have to burn the shuttle Ds engines for at least part of the final boost.

So, given all that, I decided my next project would be a launch vehicle that could take my payload all the way to orbit and give it a boost on its way, roughly in the 30 to 50 tonne payload range.

 

[Urwumpe]

Well, my current project created the need for this, as a shuttle D requires a really, really long launch fairing. I couldnt even fit it inside of the old side mount quasar, so I ended up having to use custom fairings on a Themis A launcher. The downside to that was that I could only get partway to orbital velocity on the themis, and have to burn the shuttle Ds engines for at least part of the final boost.

So, given all that, I decided my next project would be a launch vehicle that could take my payload all the way to orbit and give it a boost on its way, roughly in the 30 to 50 tonne payload range.

Why don't you launch it in sections? after all, the biggest single part you have are the tanks, and these could be welded in space from tube sections.

 

[BruceJohnJennerLawso]

Why don't you launch it in sections? after all, the biggest single part you have are the tanks, and these could be welded in space from tube sections.

I could, but I dont think I could pull off an orbital construction mod in Orbiter just yet. The payload itself is only around 25-30 metric tonnes anyways, so its probably easier to build a launch vehicle.

note: the issue here is length anyways, so chopping off the tanks wont help

 

[Urwumpe]

I could, but I dont think I could pull off an orbital construction mod in Orbiter just yet. The payload itself is only around 25-30 metric tonnes anyways, so its probably easier to build a launch vehicle.

note: the issue here is length anyways, so chopping off the tanks wont help

I meant this differently: Except the tanks, everything of your spacecraft can be separated into nice compact modules, some structural parts could even be made more compact during launch and extended in space. Yes, assembly in space isn't trivial for add-on development. But possible. You could use attachments until the spacecraft is complete.

For example if you start at the spine of your spacecraft and then install tanks, cockpit, engines, etc. to it. For example by the assistance with a robotics arm, that could also play a role for handling cargo or repairing the spacecraft.

 

[BruceJohnJennerLawso]

I meant this differently: Except the tanks, everything of your spacecraft can be separated into nice compact modules, some structural parts could even be made more compact during launch and extended in space. Yes, assembly in space isn't trivial for add-on development. But possible. You could use attachments until the spacecraft is complete.

For example if you start at the spine of your spacecraft and then install tanks, cockpit, engines, etc. to it. For example by the assistance with a robotics arm, that could also play a role for handling cargo or repairing the spacecraft.

Could you provide any suggestions on how I could code an on orbit assembly? Id love to include that in future releases, but I dont see how it can be done.

 

[Urwumpe]

Could you provide any suggestions on how I could code an on orbit assembly? Id love to include that in future releases, but I dont see how it can be done.

Well, lets assume I have full artistic freedom and an existing design of a spacecraft to be assembled:

I would start with making a construction orbit platform. Nothing more but a girder structure as support, a small habitat with airlock and docking port, an unpressurized storage of smaller parts and a rail parallel to the construction platform and longer than the spacecraft, that mounts a single robot arm. A second docking port is installed on the side with the rail.

The robot arm could have inverse kinematics, but that only makes work easier, it is not mandatory.

Next, I would launch the spine or keel of the spacecraft as first part. I dock the transport tug with the keel part to the station. Then I grapple the part with the robot arm (attachment) and move it to the construction platform. There I attach it to another attachment point, by my C++ module.

Next, I would extend the spine structure to full length and unpack the module. This could be done by UMMU action areas.

Next, the spacecraft needs the bridge. So I launch this module and again dock it to the construction platform. The robot arm grapples it, moves it to the front and attaches it to the spine (The spine is actually my spacecraft module, while all that comes attached to it is just more or less idle LEGO)

When I attach a module to the spine, it is only fixed there. Now I let UMMU astronauts connect and install it. By that action area, the attached part vessel is deleted from Orbiter and the vessel makes its own installed bridge visible. Now, I have a bridge. Not completely fitted out, but already useful. I return to the habitat of my construction platform and establish network connection to the bridge and the diagnostic system management computer system via a terminal there. I activate the computer, check that power supply by the construction platform works, etc.

Now, the other parts arrive one by one and I install it. There are some bigger tanks, that can't be launched in one piece, so I launch it in sections and weld them together at the construction platform before attaching the tanks. (Same process as for the spacecraft).

Soon, the spacecraft is completed by the outside, but still, there is a lot of work. I want to separate it from the construction platform, for freeing the platform for the next vessel to be constructed. For that, the vessel has to be prepared for leaving the wharf platform. First I check all is OK, and finish external assembly tasks by EVA. Then I remote control it and activate a local power supply installed to it. Now I have a few hours time for moving it with the robot arm to a free docking port. I detach it from the construction site, and grapple it with the robot arm (one operation with Orbiter). Then I move it, dock it to the platform and again establish power and data connection.

Now, the final work starts. First, I use the life support system of the habitat for slowly making the bridge of the spacecraft breathable by filling it with atmosphere. UCGO crates are used for delivering N2 and O2 to my platform. Then, I enter the spacecraft for the first time. I use the next work days for installing many small components that had been left on earth for fitting the modules on smaller launchers. I install CO2 scrubbers, remove protection film from the computer displays, power up the cockpit systems for tests and power them down afterwards, activate the life support system and make function tests of it. I install computer software, install seats, finish plumbing that had been hard protected from the vacuum of space by plugs during assembly.

Finally, I power up the spacecrafts own power supply for the first time, check the power systems, disconnect the power supply of the construction platform. I activate navigation systems, guidance systems, pressurize the fuel tanks. I close the hatch and undock for the first time and use a few RCS pulses for moving away, test the RCS and navigation system, always knowing that, should something fail now, a Deltaglider at the station will be ready to rescue me.

if all goes well, I continue testing the main propulsion system by increasingly large maneuvers, first small changes that would allow returning by RCS alone, later a large burn into GTO for proof testing.

After all tests done, I fly the spacecraft back to the platform and let the first crew of it take over. The spacecraft is assembled.

 

[gattispilot]

Like was said. You would have a frame or not and use attachments. Use a arm and move the piece to wear you want and switch to the vessel and attach.