Value chain · CLM-1178
In plain terms
The antenna is one twisted surface, like a ribbon turned half a turn from top to bottom. Looking down its axis you see a complete circle; from one side it looks like an hourglass, and it presents the same area to the Earth whichever way it faces.
The claim as recorded
CASSIOPeiA's elements lie on one helical surface twisted through 180 degrees from end to end. Seen along its axis it is a full disc; seen from one side it has a waist. SRC-026: "By arranging triple-dipole elements on a virtual helical surface twisted through 180[deg], having diameter D and height H, it can be shown that the aperture (projected area) viewed from any azimuth angle is a constant, 2 [x] D [x] H/[pi]". The patent's first example is "twisting a rectangular vertical plane through 180 degrees from bottom edge to top edge", and it prefers "an integer multiple of approximately 180 degrees, for example 180 degrees or 360 degrees". SRC-026 Fig. 6 includes an "orthographic polar view", which shows a full disc covered with PV. The patent's Figs 1, 2, 9, 10 and 11 draw the side outline as an hourglass, full at the ends and pinched at mid-height.
Evidence behind this: Inventor's T2 paper and T3 patent; the weaker sets the tier. The geometry is the designer's description and drawings.
Scope and limits
180 DEGREES IS THE PAPER'S VALUE AND THE PATENT'S EXAMPLE; THE PATENT ALSO ALLOWS 360 (PDF 16), so "twisted through 180 degrees" must not be written as the patent's only form. The side view 90 degrees round, a spindle full at mid-height, is not drawn in either source; it rests on the 2022 thesis alone (CLM-1181). No held source states D or H for a GEO CASSIOPeiA in this record's terms; the 1.7 km of SRC-590 PDF 29 is a slide label (T5). SRC-026's layers are strips of "linear extent D"; the thesis builds the surface from tilted hexagonal modules instead (CLM-1182), and the two constructions must not be merged.
What it assumes
That SRC-026's "orthographic polar view" is a view along the helix axis; the caption does not name the axis, and the circular outline is what makes it so. That a strip of length D turned 180 degrees about its centre sweeps a full disc of diameter D is geometry, not a source statement.
Where it comes from
PDF 4 [173], raw, transliterated: "By arranging triple-dipole elements on a virtual helical surface twisted through 180[deg], having diameter D and height H, it can be shown that the aperture (projected area) viewed from any azimuth angle is a constant, 2 [x] D [x] H/[pi]." Same page, raw: "This virtual helical surface can be divided into multiple narrow physical layers having linear extent D, upon which the elements are mounted (Fig. 4)." SRC-026 PDF 5 [174], Fig. 6 caption, raw: "CASSIOPeiA array integrated with PV, individual layers and orthographic polar view."; the right panel is a full disc tiled with PV, with a central disc and one diametral band without PV (figure reading). SRC-026 PDF 5, raw: "such that the helical arrangement has circular PV apertures available from both ecliptic-north and south (i.e. both sides)." SRC-088 PDF 28 [16], raw: "The elements are arranged such that they all lie on a common helical surface which can be described by twisting a rectangular vertical plane through 180 degrees from bottom edge to top edge, the bottom and top edges being spaced along the axis of the array." SRC-088 PDF 16 [4], raw: "It is most preferred that the helical surface twists through an integer multiple of approximately 180 degrees, for example 180 degrees or 360 degrees." SRC-088 PDF 15 [3], raw: "The helical surface may rotate through approximately 180 degrees, or a multiple of, from one end of the array to the opposing end".
Basis: twist angle in degrees; outline seen along and across the axis; projected area as 2DH/pi
Cite this
energyaperture.com/c/clm-1178
CLM-1178, Energy Aperture, as of 2019.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-026
- CLM-0004The author of the 2019 CASSIOPeiA paper states the beam's strongest point is about 230 watts per square metre, and says that figure was...CLM-0006None of the five main studies mentions the international radio-frequency exposure limits, or any safety standard, or a restricted area...CLM-0013The paper that modern UK studies rely on for the beam figure calls anything below 1 kilowatt per square metre safe, with 230 watts per...CLM-0336Different design studies over four decades have each simply assumed a different working lifetime for a solar power satellite, from about 15...CLM-0339A 2019 paper said solar power satellites are often assumed to need visits in orbit for repairs and refuelling, but that no system yet...CLM-0441A normal geostationary satellite needs a small, regular fuel-based nudge every year to stay in place. One 2019 design proposes cutting most...CLM-0504None of the main CASSIOPeiA-related documents in the register mentions any named safety or exposure standard, or describes any restricted...CLM-0660The 2019 CASSIOPeiA paper does not discuss electric propulsion for getting the satellite to its orbit. It only prices delivery using...More on the source page.
- Also from SRC-088
- CLM-0896The patent describes measuring the incoming steering signal at scattered sensors, not at every antenna, and working out the values in...CLM-0897The satellite aims its beam by listening for a low-power signal sent up from the receiving station, measuring the shape of that arriving...CLM-0899The patent never says the steering signal is protected in any way. There is a difference between scrambling that signal so nobody can read...CLM-0900The satellite can point its beam far further than there is Earth to point at, so moving power from one receiving station to another is not...CLM-0903The shared clock tells every sensor to take its reading at the same moment. How precise that clock must be depends on how fast the thing...CLM-0905Sharing a clock is not the same as being told what to do. The clock and the carrier tell the antennas nothing about where to send the power...CLM-0913When the satellite corrects its own bending by listening to the ground signal, what is left over is not how far the antennas moved. It is...CLM-0942Three documents held here give three different sizes for the same satellite's transmitting antenna. The patent says 1 to 1.5 km across and...More on the source page.