Is one of the requirements for the testbed that it demonstrate some actual human/vertebrate habitation?Otherwise, what other things need to be demonstrated in space that can't be demonstrated on Earth?
I"ll throw this into the mix, but – fair warning – I may not be able to check into this thread very often.
Quote from: HMXHMX on 05/04/2019 09:30 pmI"ll throw this into the mix, but – fair warning – I may not be able to check into this thread very often.I think you have shown this previously, and this is the type of design that I started out with originally. I went from the "I" configuration to the "X" configuration in order to deal with the "intermediate axis theorem" issues, but there may be ways to deal with it using active measures (i.e. thrusters for instance).And this type of configuration is a very simple design, and doesn't have the issues related to using cables to connect two free flying bodies. Plus it would lend itself to being built fairly quickly, and the cost of the modules would be kept low due to their common configuration. Lots to like about it.
...Is it possible to imagine mechanical actuations like these, which would somehow still allow a single contiguous volume across the entire structure, spanning across both sides of the actuated joints?
I don’t agree that variable G artificial gravity will first appear on some surface. Things have changed. We’re seeing relatively heavy sheets of stainless steel being welded together on what amounts to a seaside beach I open air. They’re being used to assemble a super heavyweight reusable launcher. Whether you subscribe to the notion that these heavy lift ships themselves would make good building blocks for an orbital spinning research facility or not, the lift capacity and, cubic volume capacity, and ready research into orbital welding, 3D printing, and robotic operations makes larger, more robust construction more possible and less expensive. Outfitting with life support, workable docking facilities and so forth leave plenty of new Engineering yet to be done. But optimization objectives have changed.In my opinion.
Quote from: Eer on 05/11/2019 10:24 pm....Whether you subscribe to the notion that these heavy lift ships themselves would make good building blocks for an orbital spinning research facility or not, the lift capacity and, cubic volume capacity, and ready research into orbital welding, 3D printing, and robotic operations makes larger, more robust construction more possible and less expensive. Outfitting with life support, workable docking facilities and so forth leave plenty of new Engineering yet to be done. But optimization objectives have changed.In my opinion.Two Starships docked nose-to-nose, or with some other structure between them for larger radius, would indeed make a good testbed. The thing is (imho) Musk isn't going to bother. The whole point of Starship is to go straight to the real thing, as fast as possible. He will get the data as a matter of course. NASA doesn't have the time or resources to reach their existing goals, much less pursue research they've historically ignored. Given Bezos' interest in space habitats, BO is the most likely player to go for it, but given their pace and current priorities, all the data will be available long before they get there.
....Whether you subscribe to the notion that these heavy lift ships themselves would make good building blocks for an orbital spinning research facility or not, the lift capacity and, cubic volume capacity, and ready research into orbital welding, 3D printing, and robotic operations makes larger, more robust construction more possible and less expensive. Outfitting with life support, workable docking facilities and so forth leave plenty of new Engineering yet to be done. But optimization objectives have changed.In my opinion.
Note that as a consequence of spinning joined pairs of Tankers and Starships, SpaceX will be able to utilize the acceleration created to settle propellants to the tops of their respective tanks. Once initiated, the spin-created artificial gravity will dispense with the need for the long-axis thruster firings that will otherwise be required. Eliminate those thruster firings, and you also eliminate the perturbations to orbital parameters that will otherwise need to be compensated for.
And now to the 800-pound gorilla in the room: the 180° shift in direction from earth-bound gravity to spin-actuated gravity. Some people will view the need to move furnishings, workstations, and all the other accoutrements from 'floor' to 'ceiling', and back again, as an insurmountable problem. I do not. Interior designers have been crafting small, tight, and odd shaped living and working quarters for literally centuries. And they did that with paper and pencils! With the CAD environment available today, I have no doubt whatever that any of a vast number of interior design houses would jump at the chance to design the staterooms that would occupy the interiors of the first interplanetary spaceships. What doing so will take is a change in perspective and a healthy dose of Imagineering.
Some people will view the need to move furnishings, workstations, and all the other accoutrements from 'floor' to 'ceiling', and back again, as an insurmountable problem. I do not. Interior designers have been crafting small, tight, and odd shaped living and working quarters for literally centuries. And they did that with paper and pencils! With the CAD environment available today, I have no doubt whatever that any of a vast number of interior design houses would jump at the chance to design the staterooms that would occupy the interiors of the first interplanetary spaceships. What doing so will take is a change in perspective and a healthy dose of Imagineering.
Moving furniture is not the concern. A complete flip of load path is the issue. Starship has been designed to be either within a 1g field in one orientation, in a 0.376g field in that same orientation, in microgravity, or under very small acceleration from RCS thruster firings.
but if you were to glue all the furniture
And vertical at 3+g. And the reverse-direction jerk-force of 3g to 0g. And horizontally, belly-side, at however many g's it pulls during re-entry, plus the bending force from aerodynamic pressure in that horizontal position.
Also, if they stick with the crane idea to lift it onto Super Heavy, then the structure will also need to support the loaded-but-unfuelled mass hanging from the nose.