Gravity Loops in Space and Comfortable Sleeper Cars

A commenter complained that he would not want to sleep on a one-gravity loop system on Mars, the Moon or elsewhere in space with low gravity or no gravity. The other complaint was that it would be too costly to build and maintain.

1. San Francisco spends $923 million to $3 billion per mile for regular subway extensions of the BART rail system

When the Salesforce Transit Center opened in San Francisco summer 2018 a new tunnel will be needed to connect it to the current Caltrain terminus in SoMa. The project, known as the Downtown Extension, is estimated to cost $3 billion for each mile of the subway, six times more than the average outside the United States. The Central Subway, a 1.7-mile tunnel that will connect Chinatown to Fourth and Brannan Streets, is a relative bargain at $923 million-per-mile. But elsewhere in the world, new subways cost half as much.

Elon Musk’s Boring Company can build 2-mile tunnels for $30 million.

2. People pay for the comfort and romance of overnight sleeper cars on tourism trains. A 500-meter train loop can comfortably provide the simulation of gravity. People would be in sleeper cars if they needed the overnight one-gee.

Sleeper cars on trains have been around since the early 1800s. Tens of thousands of people use them every year. People pay extra for the private cabin and tourism experience to watch the country side.

Solutions do not have to be uncomfortable or costly. Also, current solutions can be insanely costly. Starting fresh without costs for land rights, legal issues can make things two hundred times cheaper. This is one of the huge advantages of building on the moon and Mars. There is only transportation costs but no land costs and virtually no bureaucracy for decades.

SOURCES- Interesting Engineering, Boring Company, Wikipedia
Written By Brian Wang,

13 thoughts on “Gravity Loops in Space and Comfortable Sleeper Cars”

  1. Why design a loop when we can settle for about a dozen starships tethered to a center module.

    First rule of making space accessible is don't design it unless you need it 🙂

  2. Isn't it simpler to have a 'swing tower' (like you see at amusement parks) that rotates pods hung on cables? In low g it should be trivial to build these without a lot of material.

  3. You wouldn't build a system using a track, just spin the structure on a vertical axis, like a rotating space station, just on (or just under) the surface of the planet.

  4. Wow. Up to 3 billion dollars a mile to connect to the Salesforce Tower? Supposedly the construction cost of the tower was only 1.1 billion. Somebody is making a very comfortable living.

  5. I'm pretty sure that air pressure is going to create structure that can supply 1 g to light things very easily. ~15 psi means the air pressure area to equal *your* 150 lb mass is a square with 10 square inches, NOT 10 inches square, 3+ inches square. And that is everywhere, not just where you are.

    Musk is so wrong about so many things, IMHO. He is like Kepler, great idea led to further true great idea that would have not sprung *whole* probably. Musk rocket good.

  6. It's important for space habitats, too, you know: They should really operate at the lowest acceleration compatible with good health, for structural economy.

    And you might make a convert of Musk if it turned out people couldn't hack long periods at Martian gravity.

  7. I avoid mentioning Mars g because it is not a universal planetary problem. But it seems a worst possible case. I'm not against these sort of studies, just really against waiting for the mostly unneeded results.

  8. If 0.38 gravity isn't enough for long term health, I don't see colonization of Mars happening. The need for expensive infrastructure to compensate totally guts the case for Mars. This is something we need to know, ASAP.

    I think the case for a long duration partial gravity research lab can be made to Musk. After all, the easiest way to do it is to take two Starships outfitted exactly as they'd be for a trip to Mars, and set them in a bolo style arrangement for Mars gravity, which you would likely do anyway for a trip to Mars.

    it's a long duration partial gravity research lab, AND long duration testing of his Mars vehicle. The only thing missing would be exposure to the radiation environment, and the diminishing solar flux.

  9. I think ring rail tunnels on the moon, Mars, and asteroids carrying residential cars are a simple, effective mitigation for low-G mitigation. The technology is centuries old.

  10. In my humble opinion I think that Mars has enough gravity to allow an undetermined duration settlement, as long as you´ll do a 1 hour duration daily weight lifting workout.

  11. You would never build a train in Space, just rotate the whole thing, no moving parts. 1 g is small force compared to atmos bubble pressure requirement, so 1 g basically free if designed for. Where is the notion that 1 g sleep is good, or good enuf? They use sleep position to mimic 0 g! You need g while walking, etc to do any good, I think. That means everywhere! Hard to supply on most planets, esp those with too much g, but fine in Space. Is the surface of a planet the right place for an expanding tech civilization?

  12. Much easier to build a gravity loop train (which is really just an incomplete wheel station) in vacuum in asteroids and on the moon (see circus maximus concepts), as a simple maglev with no air drag. Mars gets more obnoxious due to drag though.

    The thought of hormonal pregnant women stuck for 9 months on a train due to 1G gravity requirements to alleviate pregnancy safety concerns will surely bring out a lot of howling. See Snowpiercer for one way that might go bad…

    Same with kids, will they be stuck on the 1G train for most of their development? Only for sleep and exercise? Or only for daytime/exercise, and sleep in reduced gravity?

Comments are closed.