# Would orbital ring platforms affect the orbit of a planet?

If we built an orbiting platform of sufficient mass (let's say, made from harvested asteroids) that was anchored at both poles of the planet it surrounded, would such an addition to the planet's mass affect its orbit? Further to this, if the sun in this hypothetical system was dying and lowering its temperature and mass over time, could an orbiting platform around a planet be used to intentionally affect its orbit such that the planet remains in the 'habitable zone' of this sun (rather than become colder and colder as the sun cooled down over time) by reducing its orbital radius?

• I thought that due to expansion of the Sun's outer layers the Earth with a 1 AU orbit gets hotter not colder? Also, changing the mass of the Earth by adding material coming in at a similar velocity to Earth's orbital velocity won't change it's velocity and therefore won't change the size of Earth's orbit. To raise or lower the orbit of the Earth significantly you have to bring in a sizable fraction of the Earth's mass at a sizably different velocity.
– uhoh
Sep 24 at 23:09
• I'm just guessing as to the purpose of your question, but you may want to consider directing any follow-up or related questions to the worldbuilding.stackexchange.com forum. Sep 25 at 12:52
• If it had 'sufficient mass' then by definition, of course it would. If it had any mass at all, it would impact the orbit but whether that effect would be significant would depend on the mass. Sep 25 at 21:07
• Could you stick to the rule of one topic per Question, and separate 'Further to this, if the sun…' into another? Sep 25 at 21:08

Backup, frameshift time:

You can't anchor your ring to the poles without making it out of handwavium.

Your ring must be at the equator. Anything else will cause torque on it that it can't hope to survive. It must also be basically self-supporting as you simply can't build load-bearing structures at that scale as nothing is strong enough.

Furthermore, it must be anchored to the planet or you will have a catastrophic failure as anything other than a massless ring has negative stability. This means the anchor points must be moving at Earth's rotational velocity.

In the simple case this means in a synchronous orbit. If you trust your engineers enough there is another option: a two-part ring, the outside part rotating with the planet and the inner part rotating well above orbital velocity to provide the force required to hold the outer part up.

As for the end of life of the star--stars get warmer over time. In the "best" case Earth's fate is to become a ball of molten lava, in the worst case it falls in. Only after that does it go out and collapse into a white dwarf. Even if you could push a planet around enough I doubt it's worthwhile to try to live on the feeble light of a white dwarf.

Also, your ring does nothing to alter the planet's orbit.

First of all, the ring you are suggesting would have to be equatorial not polar.

Secondly the sun will expand in the next million years, so prospectively it will get hotter here (and NO: that is not the reason for global warming!)

So now to your actual question: would earths orbit change significantly because of a ring space station?