...100 MW of Space Solar Power ...per single launch!
in [Physics]
|
Prev: Does inductive reasoning lead to knowledge?
Next: What is the correct term for this type of chart?
From: Sylvia Else on 25 Dec 2009 19:39 Peter Fairbrother wrote: > Sylvia Else wrote: > >> You're just not thinking this through. The solar panel has to remain >> pointed at the sun. The output microwave power has to be directed at >> Earth. The two directions rotate 360 degrees with respect to each >> other every 24 hours. Changing the phase of the elements is all very >> well, but the effective aperture of the transmitting antenna would be >> reduced as the panel gets foreshortened as seen from Earth. > > Yes. > > Further the individual >> transmitting elements, which presumably do not emit isotropically, >> would themselves have to be rotated relevative to the panel. > > No - that's what a phased array does. The individual elements radiate > over about 2 steradians, or almost half a sphere. The elements of the > array create a beam by interfering with each other, and the timing of > the phases to the elements changes the direction of the beam. As you say, half a sphere - not isotropic. Allow it to turn far enough away from the intended beam direction and it won't work. Stockton appears happy for it to turn through 360 degrees per day. Sylvia.
From: Sylvia Else on 25 Dec 2009 19:42 BradGuth wrote: > On Dec 25, 8:43 am, Peter Fairbrother <zenadsl6...(a)zen.co.uk> wrote: >> Sylvia Else wrote: >>> You're just not thinking this through. The solar panel has to remain >>> pointed at the sun. The output microwave power has to be directed at >>> Earth. The two directions rotate 360 degrees with respect to each other >>> every 24 hours. Changing the phase of the elements is all very well, but >>> the effective aperture of the transmitting antenna would be reduced as >>> the panel gets foreshortened as seen from Earth. >> Yes. >> >> Further the individual >> >>> transmitting elements, which presumably do not emit isotropically, would >>> themselves have to be rotated relevative to the panel. >> No - that's what a phased array does. The individual elements radiate >> over about 2 steradians, or almost half a sphere. The elements of the >> array create a beam by interfering with each other, and the timing of >> the phases to the elements changes the direction of the beam. >> >> BTW an array can also create two or more beams, by varying the timing of >> the phases to the elements - but this involves complex electronics. This >> technique is used on some military radar arrays, but it might be >> unsuitable for a very large array in space. >> >> Think of two beams incident on the array, and the phase pattern that >> would make. Then drive the elements to that pattern, and you get beams >> (roughly speaking). >> >> However the transmitting array would most likely be pointed directly at >> the Earth station all the time, with only minor phase changes for >> precise steering (or alternatively the phases of the elements might be >> fixed, in order to make it less complex, and the array oriented precisely). >> >> -- Peter Fairbrother > > If Sylvia Else and most others if this Usenet/newsgroup were any more > negative or naysay, they'd form into an HLC antimatter singularity or > black hole and suck all of us along with them. I've expressed some concerns about the economics. Otherwise I have no particular issue with the concept. I've pointed to some of the technical challenges, but that's not being negative, IMHO. However the implementation as envisaged by Stockton just won't work properly. Sylvia.
From: Peter Stickney on 26 Dec 2009 17:42
Pat Flannery wrote: > jmfbahciv wrote: >> Pat Flannery wrote: >>> jmfbahciv wrote: >>> >> You don't know how bad things can get. Snow, sleet, and frozen >> rain can coat anything with inches of stuff in that region. > > I live in North Dakota, and the same thing can happen around here, > despite it being as flat as a billiard table. > This could mean that the rectennas are limited to the southern parts of > the continent to escape being covered in ice. > In regards to satellite TV that's inconvenient, but when your power grid > is relying on it it becomes critical. > They are better in the south anyway, as a GEO SPS is higher in the sky > from there, so the rectenna array can be more round in shape. Pat, As a North Country Sasquatch, coming from the shadow of Mt. Washington itself, I have to say that you don't have a clue wrt the weather in that region. When we talk about inches, it's in multiples of 4. People from up there move to North Dakota for the nicer climate. The conditions that BAH are referring to are such that candidates for the Amundson/Scott Station are trained there, so that they won't complain about the conditions at the South Pole. The Standard Issue Walking Stick for the Mt. Washington Observatory in winter is a 5' steel pry bar. Anything else and you'll blow away. More s.s.h content - The Andover, ME, satellite uplink/downlink station isn't vary far from there. Oh, yeah - the Regional High School for Bethel, and Lock Mills, ME, and the surrounding villiages is Telstar Regional High. -- Pete Stickney Who can make lunch out of a red Jordan's Hot Dog, a bag of Humpty-Dumpty Potato Chips, and a bottle of Moxie. |