Is there a good free orbital simulator for Linux? I don't want a game like KSP but a simulation of orbits without much need for fancy graphics. I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required. -- Sent from my Nexus 6P with K-9 Mail.
On Friday, 23 September 2016 1:59:16 PM AEST Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
How about this? http://gmatcentral.org/ # Do you want to go to Mars but don't know when to leave or how much to bring? # Do you want to land something on the moon? The General Mission Analysis # Tool (GMAT) is an open-source space mission analysis tool to answer just # those types of questions. GMAT is developed by a team of NASA, private # industry, public, and private contributors. GMAT is intended both for # real-world engineering design studies and as a tool for education and public # engagement in the spirit of the NASA Charter. All the best, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC
On 23/09/16 13:59, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required.
I've written some opengl c++ libraries that perform classical mechanics simulations. Here is a oscillating collision simulation; note energy is conserved. Let me know if you would like to learn more about what I have done. https://www.youtube.com/watch?v=0rbhKvXcgkU
On Fri, Sep 23, 2016 at 01:59:16PM +1000, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required.
is there such a thing as a Dyson ring? I thought it was a Niven ring, as per Ringworld, Ringworld Engineers etc. and as (fans of) those books pointed out, rings are unstable no matter what. a full Dyson sphere is neutrally/meta stable, but no idea how you'd actually construct it in a stable manner... likely someone has thought about it though! short version is that gravity is a harsh mistress, often chaotic, and hard to do right over long timescales. do you think the solar system is stable? you are wrong. satellites? nope. but depends upon what timescales they drift/resonate. I mostly know about high N N-body codes, but I have a symplectic toy low N multi-timestep python code that I wrote somewhere. there are probably high performance (giga-year) public symplectic low N codes out there too. BTW all mine are collisionless. quite different to David Zuccaro's (intriguing - asteroid field?) collisional code. cheers, robin ObLinux: some sats probably run linux? :)
On Sunday, 25 September 2016 12:34:12 PM AEST Robin Humble via luv-main wrote:
On Fri, Sep 23, 2016 at 01:59:16PM +1000, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required. is there such a thing as a Dyson ring? I thought it was a Niven ring, as per Ringworld, Ringworld Engineers etc. and as (fans of) those books pointed out, rings are unstable no matter what.
I just made that term up as it seems to accurately describe it. But the term Niven Ring was invented first (I've just read the Wikipedia pages about his books).
a full Dyson sphere is neutrally/meta stable, but no idea how you'd actually construct it in a stable manner... likely someone has thought about it though!
https://en.wikipedia.org/wiki/Ringworld One thing that's noted in the Errors section of the above page is that a ringworld as a rigid structure is not in orbit around the star but spinning independently and would need attitude jets to keep it in place. A full Dyson sphere would require the same but with greater complexity as the jets could only be on the outside of the sphere.
short version is that gravity is a harsh mistress, often chaotic, and hard to do right over long timescales. do you think the solar system is stable? you are wrong. satellites? nope. but depends upon what timescales they drift/resonate.
https://en.wikipedia.org/wiki/Klemperer_rosette The Klemperer Rosette is also interesting.
I mostly know about high N N-body codes, but I have a symplectic toy low N multi-timestep python code that I wrote somewhere. there are probably high performance (giga-year) public symplectic low N codes out there too.
BTW all mine are collisionless. quite different to David Zuccaro's (intriguing - asteroid field?) collisional code.
https://en.wikipedia.org/wiki/Alastair_Reynolds Alastair Reynolds Revelation Space series features a system that had a huge number of inhabited satellites that all collided after an alien virus destroyed their computers. NB this isn't a spoiler as that collapse isn't covered in his novels. His novel set before the collapse was published long after novels set after it which mention it in passing. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
the biggest drawback for both the Niven ring and the Dyson sphere is there is no gravitational attraction inside the ring or sphere to the sphere - only towards the sun, or only on the outside.... On Mon, Sep 26, 2016 at 1:09 PM, Russell Coker via luv-main < luv-main@luv.asn.au> wrote:
On Sunday, 25 September 2016 12:34:12 PM AEST Robin Humble via luv-main wrote:
On Fri, Sep 23, 2016 at 01:59:16PM +1000, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required. is there such a thing as a Dyson ring? I thought it was a Niven ring, as per Ringworld, Ringworld Engineers etc. and as (fans of) those books pointed out, rings are unstable no matter what.
I just made that term up as it seems to accurately describe it. But the term Niven Ring was invented first (I've just read the Wikipedia pages about his books).
a full Dyson sphere is neutrally/meta stable, but no idea how you'd actually construct it in a stable manner... likely someone has thought about it though!
https://en.wikipedia.org/wiki/Ringworld
One thing that's noted in the Errors section of the above page is that a ringworld as a rigid structure is not in orbit around the star but spinning independently and would need attitude jets to keep it in place. A full Dyson sphere would require the same but with greater complexity as the jets could only be on the outside of the sphere.
short version is that gravity is a harsh mistress, often chaotic, and hard to do right over long timescales. do you think the solar system is stable? you are wrong. satellites? nope. but depends upon what timescales they drift/resonate.
https://en.wikipedia.org/wiki/Klemperer_rosette
The Klemperer Rosette is also interesting.
I mostly know about high N N-body codes, but I have a symplectic toy low N multi-timestep python code that I wrote somewhere. there are probably high performance (giga-year) public symplectic low N codes out there too.
BTW all mine are collisionless. quite different to David Zuccaro's (intriguing - asteroid field?) collisional code.
https://en.wikipedia.org/wiki/Alastair_Reynolds
Alastair Reynolds Revelation Space series features a system that had a huge number of inhabited satellites that all collided after an alien virus destroyed their computers. NB this isn't a spoiler as that collapse isn't covered in his novels. His novel set before the collapse was published long after novels set after it which mention it in passing.
-- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
_______________________________________________ luv-main mailing list luv-main@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-main
-- Dr Paul van den Bergen
On Monday, 26 September 2016 1:46:29 PM AEST Paul van den Bergen via luv-main wrote:
the biggest drawback for both the Niven ring and the Dyson sphere is there is no gravitational attraction inside the ring or sphere to the sphere - only towards the sun, or only on the outside....
The "original" Niven ring was spinning to provide centripetal force. A Dyson sphere could be spun to provide the same benefit on the inside at the equator, but that wouldn't work at the poles. https://van.physics.illinois.edu/qa/listing.php?id=1063 The Sun's gravity at Earth orbit is 0.0006 that of the Earth. A Dyson sphere of radius 1/22 of Earth's orbit would have a gravity on the outside that's about 1/3 that of the Earth (which is usable) but would have 484* the solar energy on the inside which might be good for industrial processes but not so good for providing a living surface on the outside. If an object is to be flexed then usually tensile strength is an easier engineering problem to solve than compressive strength. So a Niven ring would probably be constructed with more obtainable unobtainium than a Dyson sphere. https://en.wikipedia.org/wiki/Orion%27s_Arm Orion's Arm is interesting. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
On Mon, Sep 26, 2016 at 01:46:29PM +1000, Paul van den Bergen wrote:
the biggest drawback for both the Niven ring and the Dyson sphere is there is no gravitational attraction inside the ring or sphere to the sphere - only towards the sun, or only on the outside....
i'm surprised that nobody's mentioned Culture Orbitals yet. https://en.wikipedia.org/wiki/Orbital_%28The_Culture%29 they're much smaller than a niven ring, they orbit a star (and rotate independently) rather than encircle it - slightly tilted to get a day/night cycle as the orbital rotates. They have an AI Mind located at the "hub" craig ps: i want the culture to come rescue us humans - and our world - from capitalism. also want neural laces, mind backups, body changing, robot bodies, utopian technosocialism, AI ships with great names, and more. after 40+ years of reading science fiction, the culture is the first SF universe I actually want to live in. -- craig sanders <cas@taz.net.au>
Russell Coker via luv-main wrote:
On Sunday, 25 September 2016 12:34:12 PM AEST Robin Humble via luv-main wrote:
On Fri, Sep 23, 2016 at 01:59:16PM +1000, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux? ..............snip a full Dyson sphere is neutrally/meta stable, but no idea how you'd actually construct it in a stable manner... likely someone has thought about it though! https://en.wikipedia.org/wiki/Ringworld
One thing that's noted in the Errors section of the above page is that a ringworld as a rigid structure is not in orbit around the star but spinning independently and would need attitude jets to keep it in place. A full Dyson sphere would require the same but with greater complexity as the jets could only be on the outside of the sphere.
No doubt this is correct, but it is not intuitive; - "intuitively" one might expect that movement of the centre of mass of either: the Ringworld or the Dyson Sphere away from the centre of mass of it's star; would result in a net gravitational force and thus dynamic stability ? regards Rohan McLeod
On 23.09.2016 13:59, Russell Coker via luv-main wrote:
Is there a good free orbital simulator for Linux?
I don't want a game like KSP but a simulation of orbits without much need for fancy graphics.
I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required.
While this is not what you are looking for xephem can calcualte and show the orbits of satelites of earth as well as orbital calculations for the planets. The graphics are not very flash, the program being now something like 26 years old, but it is designed to be accurate and be used as a professional tool. The program itself has a wide range of facilties having both text and graphical displays and can directly control a telescope. There's no debian package for it, the program only being freely downloadable for none comercial use. I have though so far have ha no difficulty at all in compiling it. I noticed (just) now though there is a post about compiling it on debian 8. There are more flashy programs around now but none are so flexible and accurate as xephem. Lindsay
participants (8)
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Chris Samuel -
Craig Sanders -
David Zuccaro -
Paul van den Bergen -
Robin Humble -
Rohan McLeod -
Russell Coker -
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