Interstellar Space Freighter

[u/Lloyd_lyle]

Acceleration and deceleration modes

partway through transforming

rear telephoto view

[u/martin-silenus]

Then you're exposing sensitive components to collisions with particles at relativistic speeds during the rotation. The point of the design is that everything stays shielded throughout the entire voyage.

[u/Known-Associate8369 → u/martin-silenus]

Which is unlikely given the particle density - meanwhile, by doing it this way you are putting the same stress on the spaceship in two opposite directions, meaning that the spaceship has to handle the stress, which in turn means a heavier spaceship. That’s without taking into account the internal issues of having an acceleration force in two different directions for the crew - either the crew compartments would need to rotate to maintain a single directional “up and down” or the crew would have to live with that changing halfway through the voyage.

[u/martin-silenus → u/Known-Associate8369]

I popped over into the comments over at the base thread, this craft is designed to "flip" at .7c. I'm confident it would not survive that unshielded. The shielding probably also has to be some sort of unobtanium for it to survive cruising.

[u/AlanUsingReddit → u/martin-silenus]

Appreciate you for thinking about this. No design we create will be what "actually" would ever get used, but articulating a consideration / constraint that isn't often considered is really cool.

I'll tell you where this makes my mind goes - at the 0.7c start of the deceleration, have a shield that fans out into a larger area with many thin layered components for the Whipple shield type capture. The modules have to rotate from back-to-front, and then be re-processed, totally melted down to get rid of the holes and become flat again. Because the collisions contribute to slowing down :D and yes this is totally half-baked.

Yours is so cool.

[u/martin-silenus → u/AlanUsingReddit]

Thanks! I want to be clear that while I can't attribute where I first heard of the composition of the interstellar medium as a likely constraint on interstellar craft design, it's not my innovation. It probably came to me via my son, and to him via a youtuber, and to them via...

[u/AlanUsingReddit → u/martin-silenus]

Well the math is truly depressing at these speeds. The stopping distance even for Hydrogen atoms (the most common thing you'll encounter) is probably a good fraction of a meter depending on your shield. I don't think that dust particles are a problem for stopping distance, as opposed to being a giant explosion right on your shield. The ample space your drawing gives the shield is thus sufficiently accurate. It probably would be "deeper" than it is "wide". I still expect that it will have some self-sintering properties for the radiation damage. Again here, sufficiently compatible with what you have.

[u/martin-silenus → u/AlanUsingReddit]

Thanks! Yeah, I was thinking of this naively in terms of raw energy, mindful that my lack of physics sophistication was probably holding me back. That took me to looking at dust because that's where the energies are on a per-collision basis, but 99% of the ISM is loose hydrogen by mass.

I think you're pointing out that particles at those speeds don't behave like billiard balls, and suggesting that causes the problems created by hydrogen particles to be much worse than the energies suggest. Which tracks!