Welcome to Keen Software House Forums! Log in or Sign up to interact with the KSH community.
  1. You are currently browsing our forum as a guest. Create your own forum account to access all forum functionality.

Let us build solar sails

Discussion in 'Suggestions and Feedback' started by jaunetajabe, May 13, 2015.

Thread Status:
This last post in this thread was made more than 31 days old.
  1. jaunetajabe Apprentice Engineer

    Messages:
    111
    One day traveling from Basque country to Ireland an scientist who worked in ESA told me about the solar sails that the ESA(European Space agency) is now researching!

    I leave a webpage about them

    Could be fantastic build them and using rotors move and expand and collapse!

    http://en.wikipedia.org/wiki/Solar_sail
     
  2. Bumber Senior Engineer

    Messages:
    1,018
    It's useless compared to a solar panel plus thruster. First, it can only move you away from the sun (you can't store the energy.) Second, the thrust per area is much lower and probably can't be improved a whole lot even with future technology.
     
  3. Ulfsark Master Engineer

    Messages:
    3,057
    solar sails, although possible, will forever remain a pipe dream.
     
  4. plaYer2k Master Engineer

    Messages:
    3,160
    While the solar sail itself sure would generate low thrust, combined with solar panels it could additionally generate energy.
    It would however still be limited to the vector off the sun.

    Thus i am not sure if it were a pipe dream.
    If you would consider its feasibility in relation to other already present gameplay changes, like the already way too high thruster force, solar panel output and alike, it would become feasible again.
    However the fact that there would be just one direction such a system could work might less be a feature only for a certain block but more a general "realism functionality affecting all blocks facing the sun.

    Imagine if every sun exposed block would undergo "solar pressure" where each blocks face would be pushed based on its surface along the sun vector. That would add both a push effect away from the sun aswell as certain rotation effects based on your ships rotation and thus in both cases require stabilization.

    However, while that sure is a very nice idea toward realism and gameplay, it might be a performance killer by the current state of optimization. I would welcome that for any block as general feature.
     
  5. Harrekin Master Engineer

    Messages:
    3,077
    There is no "sun"...

    It's essentially a light in the roof...
     
  6. Malware Master Engineer

    Messages:
    9,632
    Sure there's a sun. True, it's represented by a directional light and a simple decal texture, but for all intents and purposes of the game world, taking vanilla speeds into consideration, there's a sun.

    (I apologize, I'm just in that kind of mood :))
     
  7. Harrekin Master Engineer

    Messages:
    3,077
    Can you fly to it?

    (Sorry, also one of those moods ;) )
     
  8. Malware Master Engineer

    Messages:
    9,632
    Considering the max speeds of your ships, could you, in any reasonable amount of time? Even if there was a tangible model out there?
     
  9. Harrekin Master Engineer

    Messages:
    3,077
    Yes, and you know many other people would just for the lolz :)

    First thing they'd try?

    How close can you fly to it.
     
  10. Malware Master Engineer

    Messages:
    9,632
    It doesn't matter "how close" you can get or whether people tries or not, because again, even if there was a tangiable model out there, it would be too far away. If we assume we're in the asteroid belt between mars and jupiter, that's in average of about 450 000 000 kilometers from the sun. The maximum speed of our ships are 104 m/s => 374 km/h => 1 203 209 hours journey. So it would look the same.
     
  11. Harrekin Master Engineer

    Messages:
    3,077
    And yet we're getting interplanetary travel ;)
     
  12. Malware Master Engineer

    Messages:
    9,632
    Well who knows what will happen with the speeds and the sun in the future, I'm speaking of now.
     
  13. Harrekin Master Engineer

    Messages:
    3,077
    There is in fact, no spoon
     
  14. Malware Master Engineer

    Messages:
    9,632
    ERMERGERD! You're right! What was I thinking! My most sincere apologies. I humbly withdraw my statement and hereby, officially, agree:

    There is no sun.

    I.e. You win by paraphrasing one of my favorite films :) Note to self. It's been a while. Time to see them again.
     
    Last edited: May 13, 2015
    • Like Like x 1
  15. EternityTide Senior Engineer

    Messages:
    1,950
    Ignoring the fact that there is no sun, an 800m x 800m solar sail provides 5 newtons of thrust (at 1 AU from our sun, it will decrease as it gets further out, in accordance with the inverse square law). Which means that if your ship HAS A MASS OF around 100kg (which is a featherweight compared with most of our ships) you will have an acceleration of 0.05 m/s/s which means it will take you 60 seconds to get to 3 m/s. I don't know about you, but I'd prefer my ships a little more snappy than that.
    EDITED: Because certain individuals have to pick holes even when a mistake is easily understood to be what the original author intended
     
    Last edited: May 13, 2015
  16. jaunetajabe Apprentice Engineer

    Messages:
    111
    Solar sails of 2077 would be more efficient!
     
  17. mexmer Senior Engineer

    Messages:
    1,977
    even sail for small ship will be few miles large, and cannot be used for energy collection (to reduce it weight, otherwise it will make sale extremely ineffective due aditional weight)., solar sails are indead pipe dream, unless you plan to use it as "thrust" for far away exploring drone.

    considering construction of our solar panels, they cannot be used as sails even in distant dreams and those are rather simplistic.
    1000 newtons ... still not enough ;o)
     
  18. Killacyte Senior Engineer

    Messages:
    1,659
    Solar pressure is such a tiny force, it's completely insignificant almost all the time. It is not worth putting the mechanics into the game.
    We will not be able to make the sun produce more force on a surface. All we could do is reduce the weight of materials. And here we have EternityTide's example from above.
    100kg really is a featherweight, especially with an 800m x800m structure.
     
  19. EternityTide Senior Engineer

    Messages:
    1,950
    "more efficient"
    the problem here is nothing to do with the "efficiency" of the solar sail, it's just that the radiation pressure from the sun at 1 AU is tiny (about 0.0000078 pascals). Unless you can get the sun to produce higher levels of radiation pressure at the distance you want, it is useless. Solar sails are only really worth it for long term space probes, and even then, I'm pretty sure most people would prefer the old RTG/ion thruster combo rather than a sail which only travels in one direction, and as it travels in that direction, it loses thrust.
    Additionally, solar sails are useless outside of stellar space. Once you exit the solar system, you pass through a membrane called the heliopause. This what is called the "termination shock" of the solar wind. Once you get past this, your thrust will be negligible. The galactic wind is tiny, and the solar wind stops at the heliopause, so you are limited by the availability of viable radiation pressure
     
  20. plaYer2k Master Engineer

    Messages:
    3,160
    Like i already said, there are many differences off realism for the sake of gameplay. Thrusters forces and solar panels outputs are two important here as they both are affected by values the sails would be too. One being the "efficiency of the sun" and the other is the simple propulsion.

    So if there were sails, these values for realistic sails we know right now are irrelevant and only the functionality/gameplay aspect matters for the sake of this discussion.

    I also dont know why everyone talks about weight. No matter how massive, it weights nothing in space with no gravity around *hurrdurr ;D*

    But that is already done. *looks above*
    A solar panel produces 120 kW over 50 m² and thus 2 400 W/m². At earths distance to our sun, we have roughly 1400 W/m².
    To get 2 500 W/m² solar radiation, you had to be at the distance of Venus with about 0.7 AU distance to the sun, and we are way beyond that...
    So any comparison in that regard is pointless due to other unrealistic gameplay considerations already made.
     
    • Like Like x 1
  21. Killacyte Senior Engineer

    Messages:
    1,659
    Eh? You're using mostly arbitrary power outputs (balancing issue) to say that we've somehow made the sun more forceful? If we are at a distance to the sun that, right now, would have solar energy exert a pressure of 5 N on a surface, it will always be 5 N at that distance unless the sun itself changes. We can't change the force part of the acceleration equation in this regard, just the mass.
     
  22. CruentaUltio Apprentice Engineer

    Messages:
    229
    Wait ... there are persons who weigh 100kg... How can a 800x800m structure be so light? Made of paper? (and even that would weighs tens if not hundreds of tonnes)
     
  23. Killacyte Senior Engineer

    Messages:
    1,659
    Hypothetical best-case scenario.
     
  24. EternityTide Senior Engineer

    Messages:
    1,950
    You know we are talking about mass, don't be pedantic.
    Secondly, energy-conversion-wise, solar sails are a horrifically inefficient means of taking energy out of light. The photoelectric effect is a lot more efficient, hence solar panels.
     
  25. plaYer2k Master Engineer

    Messages:
    3,160
    So many trying to be overly correct with their values to underline their point while ignoring any potential gameplay factor. Yet their correctness ends when it comes to fundamental terminology like weight vs mass.
    How should someone take one persons argument throwing scientific values and words around any serious if they cant differ mass and force.
    If someone wants to talk about proper math, exponentials and co, they should prove their understanding of the multiplication table first.

    Also accusing someone being pedantic is flawed with those blatant errors while pretending to be scientific.


    Edit: reply to @EternityTide in order to not further derail the thread

    You may or may not percept it as being aggressive. I can tell you that i am calmly stating my opinion.
    However people tend to percept opposite opinions as being aggressive and offensive.

    You know what you meant, i do and some others sure did too. The problem is not those who do but those who dont.
    By maintaining a wrong or flawed paradigm you essentially teach those who didnt know yet with what essentially is wrong.
    Instead of making people aware of the difference and how important it can be, it just gets handwaved as "yeah we know".

    I also merely made a casual note there and i dont see the need to distract the thread now, hence why i added it as an edit instead of a new post.
     
    Last edited: May 13, 2015
  26. EternityTide Senior Engineer

    Messages:
    1,950
    Ok, if you say so. May I ask, do you always have to make discussions so aggressive? You knew what I meant anyway, so no harm done. I'll edit it now if it'll stop you from turning this discussion into yet another flamewar.
    And I'm not "pretending to be scientific", we're doing back-of-a-manila-envelope calculations to get rough approximations of the physics behind something.
    calm down and stop trying to make everyone angry by inciting a finger-pointing session.
     
  27. Killacyte Senior Engineer

    Messages:
    1,659
    Ok, this really is such a wasteful arguing point. Everything I'm reading where people (accidentally) put "weight" can change the word out to "mass", and their arguments are still perfectly fine. No-one was making bad points, and pushing the mass-not-weight thing becomes irrelevant.
     
  28. EternityTide Senior Engineer

    Messages:
    1,950
    Just ignore it. It's only someone trying to escalate this into a flamewar. Anyway, the MASS of most ships is beyond the abilities of the largest solar sail to create a feasible amount of thrust
     
  29. SenorZorros Master Engineer

    Messages:
    7,063
    define "large".

    still, while solar saild may be the solar panels of thrust I do agree that a feasibly sized sail would take more than 10 seconds to travel from tip to tip even if you use thrusters.
     
  30. Bumber Senior Engineer

    Messages:
    1,018
    Several hundred Tens of thousands of square kilometers (to match one small thruster at a perfect 9.08 N/km^2.)
     
    Last edited: May 14, 2015
Thread Status:
This last post in this thread was made more than 31 days old.