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tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,440

Rotating Propellant Delivery Engineering

This topic is focused upon a proposal to deliver propellant in liquid form to a receiving system (another ship or a refueling depot).

The proposal is laid out in a paper by GW Johnson, which is (hopefully) available upon request.

This topic is offered for discussion of two versions of the proposal.

This technology is NOT (end over end) rotation .... it is rotation of a delivery tank around it's longitudinal axis.

The first version is physical rotation of the delivery vehicle.

An alternative that I have not seen published (but which may well HAVE been published) is to rotate the liquid inside the tank while the ship itself remains firmly attached to the receiving system.

The mechanisms needed to facilitate successful propellant transfer on orbit are the focus of this topic.

I would prefer that posts to this topic consist of engineering related information or guidance.

Opinions about people or groups of people have no place in this topic, and I respectfully request they be published in suitable topics elsewhere in the forum.

(th)

Calliban

Member

From: Northern England, UK

Registered: 2019-08-18

Posts: 3,796

Re: Rotating Propellant Delivery Engineering

Why is it neccesary to detatch the propellant tank from the refuelling depot?  The entire depot can be rotated at slow speed using a reaction wheel.

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,440

Re: Rotating Propellant Delivery Engineering

For Calliban re #2

Thanks for adding this interesting  variation to the fuel delivery scenario.

The solution to be developed might have more than one manifestation.

A delivery between two space craft (such as an expedition headed to Mars) might employ a solution that differs from that used at a gigantic ISS sized station.

It should be possible to work up comparisons of the various proposals, so that costs and effectiveness can be evaluated.

Candidates for refueling (that I know about) include:

1) Traditional gravity (eg, Moon or moons of other planets)
2) Simulated gravity (small jets which expend fuel to provide acceleration) or rotation (three versions so far)
3) RobertDyck's favorite .... a bladder able to deal with cryogenic temperatures and the challenges of folding
4) Calliban's piston (with or without a seal)

Others can be added to this list as they are revealed

SearchTerm:Propellant delivery options

(th)

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: Rotating Propellant Delivery Engineering

Here is the post

This one stores all kinds of propellants,  and can maneuver to rendezvous with spent stages,  and even add solid-propellant deorbit cartridges to them.  It may require a crew to operate,  who can be sent up in a taxi space capsule,  for a moderately-short mission.  It can transfer any type of propellant to any spacecraft,  without (!!!) spinning the entire facility for artificial gravity,  or without (!!!) utilizing ullage thrust,  or without (!!!) presuming cryogenic bladders will really work.  It can help with orbital debris elimination.

This concept PRESUMES propellant transfers from spent stages can be made WITHOUT ullage thrust,  that is perhaps the weak point.  This thing can be docked together on-orbit from modules and pieces sent up by pretty much any launch rocket.  However,  I'm guessing that the propulsion module can supply adequate ullage thrust for a cryo transfer from a spent stage that is not bladdered in any way.  Everything else is covered.  Cryo pressurization above the evaporation point is cryo vapor ONLY as the atmosphere.  Any convenient non-reactive gas can be used for the storable bladder pressurant,  but,  DO NOT MIX THEM !!!!  I suggest dry nitrogen.

Attached are 3 png files I drew in Windows "Paintbrush",  one for the cryo tank modules that spin,  one for the storable propellant modules that do not spin,  and one for the facility all docked together,  complete with a command module and a propulsion module.  A whole bunch of spacecraft can dock with this thing simultaneously.  Would have to start running real numbers to real requirements (there are none as yet !!!) to refine this concept any further. This concept addresses ALL the issues that I and others have raised.

All from this topic On Orbit fuel depot