[decimon]

Caption: This is a schematic of displaced geostationary orbit.

Credit: Advanced Space Concepts Laboratory, University of Strathclyde

Usage Restrictions: None

[decimon]

Orbituary ping.

[agere_contra]

These orbits could be used to provide new vantage points to view the Earth's polar regions for climate monitoring.

Which is code for agenda-driven science.

Shame, because the technique is interesting. However it's just going to be used for/funded by more climate garbage.

[bunkerhill7]

Scots engineers prove space pioneer’s 25-year-old theory (displaced orbits for satellites)
Wait! Could there be a spaced-out connection to Displaced Immigrant Alien Travelers found in the in the Arizona wilderness by U.S. Park Rangers??

[Army Air Corps]

Ping.

[r9etb]

Although the displacement distance above or below the equator is small - of the order of 10 to 50 km - work on hybrid solar sails, which use both light pressure and thrust from a conventional electric propulsion system, is underway and aims to improve the displacement distance.

Just to put things in perspective: at GEO altitudes, a 50 km displacement corresponds to a truly insignificant 0.07 degrees in elevation.

They'd need to get about 10 degrees of elevation shift for this idea to have any practical utility.

I seriously doubt they're anywhere close to that.

[Erasmus]

If you’re going to keep station over a pole, you’re going to be sitting there with no orbital momentum. This means that the always-present weight vector, pointing at the center of the earth, will have to be counteracted with an equal amount of upward thrust from some source or another, for the entire lifetime of the satellite.

(Of course, the higher the altitude, the less the weight for a given mass, and therefore the less the required thrust.)

It’s by no means obvious how they can utilize solar pressure in the polar sitting-case, since its force is always directed at 90 +/- 22 degrees from the needed direction. Converting that force into thrust using an ion engine, for instance, that could (1) Counteract the sunlight force itself, and (2) Provide levitating force equal to the weight of the satellite, would seem to violate the laws of Physics.

I can conclude only that they are assuming the presence consumable fuels onboard. But how long could such a satellite remain on station given the levitating impulse (thrust * time) available from any present or achievable or proposed, thruster technology? In terms of thrust alone, no presently achievable ion engine would even be close to supporting its own weight (even at, say, 40 000 KM), much less the weight of a practical satellite.

** Side note: Let us define a “classical” orbit as being one where the satellite is not subjected to external forces. This means that the orbit will be planar, with one focus at the center of the earth. (This leaves aside the secondary effects of solar pressure, drag from micro-atmosphere, and tidal irregularities from the earth, moon, and other massive objects.)

Now consider the case of a geosynchronous orbit in the plane of the equator. To “levitate” this orbit so that it follows a line of latitude away from the equator takes increasing amounts of thrust (power). The extreme case is considered above; viz., the polar-sitting case.

[bruin66]

I’m really annoyed that the author uses “Geostionary” when they should use “Geosynchronous”.

[ModelBreaker]

Does this really “prove” anything? Seems to me a satellite with a solar sail in a stable orbit would be a lot more like “proof.”

[Celtic Conservative]

Scots engineers prove space pioneer's 25-year-old theory (displaced orbits for satellites)

Who else where ye' expectin'?

CC

[JRios1968]

[KevinDavis]

[SunkenCiv]

Thanks decimon! And thanks also to KD for the additional ping (see Forward's talk about space tethers). This is one of those collateral interest topics for the String Theory ping list, and because the late Dr. Robert L. Forward wrote "Future Magic" which must be around here somewhere, and I can't remember how, but there's a catastrophism connection in that book. Somehow. :')

· join · view topics · view or post blog · bookmark · post new topic · subscribe ·

[SunkenCiv]

Thanks decimon! And thanks also to KD for the additional ping.

---

· List topics · post a topic · subscribe · Google ·

---

[wastedyears]

I figured we had satellites already orbiting like that.