Space Elevator in a nutshell

Terraformer · 2020-04-10 06:08:31

On a small body such as Ceres, a space elevator needn't be a tensile structure.

spreadsheet

That said, according to Hop a Cererean elevator wouldn't have a counterweight, since the forces are so low it would have to be absolutely massive and it's a lot easier just to extend the tether to 2000km to counterbalance the forces. To move a payload from the surface would involve working against gravity up to synchronous orbit, but beyond that centrifugal force takes over and it would actually generate power.

The thing to bear in mind is, the tether connects the payload to Ceres itself. They can't be treated as separate objects. The angular momentum gained by the payload is lost by the planet.

Last edited by Terraformer (2020-04-10 06:09:50)

tahanson43206 · 2021-01-07 10:33:10

From the ID Recovery project topic:

Here is a member from 2004 whose name I instantly recognized ...

Brian Dunbar is notable for his vision of a space elevator, and his energetic efforts to promote the idea, and to try to help to advance the science and engineering that would be required. I think it is commendable that he included the Mars Society in his outreach efforts.

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Brian Dunbar | Facebookwww.facebook.com › brian.dunbar.16
LiftPort Group, founded in April, 2003, is a group of companies dedicated to building the LiftPort Space Elevator. Our goal is to provide the world a mass ...
Liftport - The Space Elevator Companies Shuts Down ...spaceref.com › space-elevator › liftport---the-space-ele...
Apr 17, 2007 — So I'm not surprised to read that Liftport has shut down operations. This is according to what's posted by Brian Dunbar in the Liftport blog.
How Does The Space Elevator Work? | The Space Elevator Blogwww.spaceelevatorblog.com › ...
Subject: Re: space elevator article. Date: Wed, 30 May 2007 13:15:32 +0300. From: lucian dorneanu. Organization: Softpedia To: brian.dunbar@liftport.com. Hi,.
LiftPort follow-up : The Name Inspectorwww.thenameinspector.com › liftport-follow-up
The Name Inspector would like to thank Michael Laine and Brian Dunbar for their gracious responses to his critical comments about the name LiftPort. Brian ...
Brian Dunbar • User • The Register Forumsforums.theregister.com › user
... we'd be the first user - it would be foolish to think that using a new material in such a critical application is a good idea; clearly it's not. Brian Dunbar. LiftPort.
A Source of Comfort - Space For Commerce, by Brian Dunbar: Liftportspace4commerce.blogspot.com › 2006/04 › liftport-sou...
A further source of comfort to this sceptic is the regular newsletters that he receives from The Liftport Group, a consortium of private companies whose object is to ...
Liftport Concert Ticket - Space For Commerce, by Brian Dunbarspace4commerce.blogspot.com › 2006/08 › liftport-conce...
This is not a mock-up of a Liftport Tickets - they look better. This is just for fun. Ticket courtesy Concert Ticket Generator. Via. Posted by Brian Dunbar at 10:39 PM.
What to Do in Space? - Open Source with Christopher Lydonradioopensource.org › what-to-do-in-space
Feb 8, 2007 — Brian Dunbar, in a comment to Open Source, 1/11/07. Toys on the moon! [fdecomite / Flickr] ... Michael Laine. Founder, president, LiftPort ...
About Brian Dunbar | Flickrwww.flickr.com › people
Interested in low-cost space access? See www.liftport.com.
Space Tether and Space Elevator Update - NASA Watchnasawatch.com › archives › 2007/04 › space-tether-and...
... done it a few times. So I'm not surprised to read that Liftport has shut down operations. This is according to what's posted by Brian Dunbar in the Liftport blog." ...
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SpaceNut · 2021-01-23 21:38:06

Space Payload Costs Are Keeping Us on Earth. The Solution? Space Elevators.

tahanson43206 · 2021-01-23 21:49:03

For SpaceNut re #28

Thanks for the update on the field ... It's good to have the 63 Gigapascals figure readily at hand, in case a discussion occurs about space elevators.

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Calliban · 2021-01-24 04:00:02

It sounds exciting. But the required tensile strength of materials would appear to make it impractical, if not physically impossible. And it would be vulnerable to collision with satellites and aircraft.

There are other means of reducing launch costs that are far closer to realistic practicality. Electromagnetic sled launch assist has been discussed on this board on multiple occasions. It would appear to me that the technology is sufficiently mature to eliminate the need for a lower stage during space launch, essentially allowing fully reusable SSTO. If I were to put money on a near term technology for substantially reducing cost of access to space, then this would be it.

On other worlds, the conclusion may be different.

tahanson43206 · 2021-01-24 08:47:13

For Calliban re #30

For Earth, I agree with you, but for Mars it appears to be practical in a hybrid form ... Earlier in this forum there are posts which explore the idea suggested by a gent recommended by Louis, to drop a cable from Phobos. I ** think ** the gent's name was ? Hop ? ... In any case, the lower tip of the cable would ride just above the top of the atmosphere of Mars, where a high speed transport could catch it for upload, and from which it could drop off vehicles designed to deal with the rate of movement with respect to the surface of the planet.

The problem is even easier at the Moon, if a line is dropped from L1, and extended back toward Earth to balance the load. This has been explored in a serious way by a team who secured a NASA grant to perform the study. I ** think ** the team was headed by Jerome Pearson, who has been a leading advocate of tethers of various kinds for many years. I ** think ** Mr. Pearson is still with us, but he ** is ** getting up there.

Not too long ago, in forum terms, Terraformer explored the possibility of setting up an elevator at Ceres, to participate in a triangle of trade in system.

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Oldfart1939 · 2021-01-24 11:05:03

My 2 Cents here; everyone should read Robert Zubrin's book "Entering Space." He discusses the concept of a Space Elevator in his usual fine detail. His conclusion is the same as Calliban stated: impossible here on Earth due to our gravity well. Possible for the moon and probably Mars.
This concept was introduced early-on in a novel by Arthur C. Clark, "The Fountains of Paradise."

SpaceNut · 2021-06-15 19:27:08

Here is one of the topics that this fits

kbd512 wrote:

Robert,
Apologies, as I was lumping in Phobos-based rotorvators in with space elevators.
EXTRA-TERRESTRIAL SPACE ELEVATORS AND THE NASA 2050 STRATEGIC VISION
It's solar powered. Doesn't that make all actual engineering issues instantly disappear in a puff of green ideology?
Sorry, couldn't resist.
Anyway, satellites would only collide if they couldn't perform avoidance maneuvers.
Regarding the harmonic orbits, people interested in space elevators, that's who.

Mars_B4_Moon · 2022-04-14 04:40:51

How Space Elevators Could Lift Up Humanity: Our Ticket to the Stars.
https://medium.com/the-universe-is-a-me … fa257b00e2

Calliban · 2022-04-14 09:24:17

Going back to the space elevator built on Ceres. The surface rotational velocity of Ceres is 92m/s. If we extend the elevator beyond geostationary point, we can use Ceres own angular momentum to hurl payloads like a sling. This is important, because Ceres is about 10% water ice. One solution for terraforming Mars would be to mine water on Ceres and use the elevator to throw payloads onto elliptical orbits about the sun that cross the orbit of Mars. We would need to design these so that they completely break up into chunks no larger than a fist, before hitting the Martian atmosphere.

We would need about 700,000 cubic kilometres of water ice to generate a 0.2 bar oxygen atmosphere on Mars. That is about 1 cubic kilometre per day for 1800 years. A lot of ice to shift. This would still be only 1% of water on Ceres. Reducing the energy cost of achieving this is one way of keeping it affordable. If we can find relatively enriched ice deposits on Ceres, which are better than 50% water by weight, we can cut the ice out rather than having to melt it. We can package the crushed ice into aluminium mylar bags and use the rotational energy of the asteroid to lift them off the surface and hurl them into space. We can ensure adequate dispersal upon hitting the Martian atmosphere by rotating the bags. As they hit the ionosphere, the bags will burst and ice lumps will disperse by angular momentum.

Last edited by Calliban (2022-04-14 09:45:40)

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#26 2020-04-10 06:08:31

Re: Space Elevator in a nutshell

#27 2021-01-07 10:33:10

Re: Space Elevator in a nutshell

#28 2021-01-23 21:38:06

Re: Space Elevator in a nutshell

#29 2021-01-23 21:49:03

Re: Space Elevator in a nutshell

#30 2021-01-24 04:00:02

Re: Space Elevator in a nutshell

#31 2021-01-24 08:47:13

Re: Space Elevator in a nutshell

#32 2021-01-24 11:05:03

Re: Space Elevator in a nutshell

#33 2021-06-15 19:27:08

Re: Space Elevator in a nutshell

#34 2022-04-14 04:40:51

Re: Space Elevator in a nutshell

#35 2022-04-14 09:24:17

Re: Space Elevator in a nutshell

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