2 ms·

>That's the source of the problem, the force you're counteracting is the same as the weight of the ship on Earth. What is being asked here is to hang a loaded s

>That's the source of the problem, the force you're counteracting is the same as the weight of the ship on Earth. What is being asked here is to hang a loaded spaceship from a building with cables. We're talking about 10,000-100,000lb (i.e. just the crew module) depending on mission profile and the craft in question. You can handle that and more with commodity wire rope and hardware. Whoever we're sending to Mars will probably appreciate having a useful tow rope on Mars anyway so it's probably wise to just use a boring old steel cable rather than something that weighs 3lb but isn't up to the rigors of surface use. Remember, we're using "needs to go into space" margins here, not "overhead lifting on earth in a jurisdiction where OSHA matters" or "what makes Redditors sleep at night" margins here so you're not going to need a behemoth of a cable. Furthermore, you don't even need to generate 1g, just enough to not cause health problems and greatly simplify craft design.

kamray23 5y ago
Yeah something that small is going to be fine. But the ISS will not be. It's 440 metric tons, generating 4.4 MN of force on a cable. That's not going to spin. And you're sending something to Mars here. In the ideal case we'll be sending six worth of supplies at the same time per person per ship. The amount of people permitted by NASA's guidelines on long-term habitation on a ship based purely on volume range from 1 for smaller ships to 30 for something the size of Starship. Hauling everything they need is not going to be below 50 metric tonnes by any means. We can probably spin as much as we like here, near the Earth, but anything further away is going to have ropes the breaking strength of which is again measured in meganewtons and the width of which is going to be around half a meter. Making that out of steel for the kind of cable you'd need for comfortable spinning (~1 rpm, 1.6 km of cable) is not going to space any time soon. At the very least 6 months of food is required for the crew module, or some complex procedure of periodic de-spin & rendezvous with a cargo vessel. The kinds of missions NASA has been planning are 30 months in overall length if everything goes well, though 24 of that is not required to be accessible during transit. Spinning again in ĺow martian orbit is going to be quite feasible, once you jettison all of your life support and such and instead do very frequent cargo stops.

kamray23 5y ago

Yeah something that small is going to be fine. But the ISS will not be. It's 440 metric tons, generating 4.4 MN of force on a cable. That's not going to spin. And you're sending something to Mars here. In the ideal case we'll be sending six worth of supplies at the same time per person per ship. The amount of people permitted by NASA's guidelines on long-term habitation on a ship based purely on volume range from 1 for smaller ships to 30 for something the size of Starship. Hauling everything they need is not going to be below 50 metric tonnes by any means. We can probably spin as much as we like here, near the Earth, but anything further away is going to have ropes the breaking strength of which is again measured in meganewtons and the width of which is going to be around half a meter. Making that out of steel for the kind of cable you'd need for comfortable spinning (~1 rpm, 1.6 km of cable) is not going to space any time soon. At the very least 6 months of food is required for the crew module, or some complex procedure of periodic de-spin & rendezvous with a cargo vessel. The kinds of missions NASA has been planning are 30 months in overall length if everything goes well, though 24 of that is not required to be accessible during transit. Spinning again in ĺow martian orbit is going to be quite feasible, once you jettison all of your life support and such and instead do very frequent cargo stops.