Value chain · CLM-0938
In plain terms
A 1988 NASA paper says a rectenna built on mylar reached 85 per cent efficiency. The 1987 final report of the contract it cites says mylar managed 70 per cent, and that 85 per cent needed a different plastic.
The claim as recorded
The final report of contract NAS3-22764 states that its thin-film rectenna element reached 85 per cent efficiency only after mylar was abandoned as the substrate, and that the mylar-based element was 70 per cent efficient. A later NASA Lewis document, SRC-417, attributes the 85 per cent figure to a mylar substrate while citing this same contract by number. The primary report of the work is the document that disagrees.
Evidence behind this: T3-primary-report. The final report of the contract in question, read first-hand. T3 rather than higher because it is a contractor report to a sponsor, not peer-reviewed; it is nonetheless the primary and most authoritative record of what this contract achieved, and SRC-417 is a viewgraph proceedings of the same tier describing it second-hand.
Scope and limits
SRC-417 IS A VIEWGRAPH PROCEEDINGS AND THE SENTENCE IS IN ITS INTRODUCTORY BACKGROUND SECTION, NOT IN A CONTRIBUTED PAPER. It may be a compression rather than an error, since the contract did begin from a mylar element - but it states 85 per cent and mylar in one sentence and the primary report separates them. Nothing here establishes which substrate the 200 g/m2 and 1 kW/m2 figures belong to; only the efficiency is contradicted. AND THE 85 PER CENT ITSELF IS NARROWER THAN EITHER DOCUMENT'S USE OF IT - it is one element in a closed system under convective air cooling, recorded separately.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.96, verbatim at the normalised level: "This 85% efficiency contrasts with the 70% efficiency of the mylar based element." Cause, PDF p.44: "unexpectedly high loss in the mylar and expected losses in adhesive". Replacement material, PDF p.8: "a laminate of Kapton F and copper was a much better material". THE DISAGREEING SENTENCE IN SRC-417 IS TRANSCRIBED, NOT QUOTED, AND THE DISTINCTION IS DELIBERATE: that document's text layer is letter-for-digit corrupted and the knowledge base does not repair a scan and call the result verbatim. Raw tokens, SRC-417 PDF p.9:a thln-Fllmmylarsubstrateyleldlng200g/m 2,I kW/m 2,andabout85percentefficiencyat2.45GHz.Transcribed: "built on a thin-film mylar substrate yielding 200 g/m2, 1 kW/m2, and about 85 percent efficiency at 2.45 GHz". It matches at no pdfnorm level, and the failure is the corruption rather than an absence.
Related records
- Answers question
- QST-002 not published in this release
- Contradicts
- CLM-0939 The 85 per cent figure that later papers quote flat was one component on a bench, in moving... **No CLM. This claim is against a sentence in SRC-417 p.9 that no registered record carries** - **THE EVIDENCE FOR THAT WAS RESTATED 2026-09-15 BECAUSE THE FIRST VERSION FALSIFIED ITSELF WITHIN HOURS AND ONE OF ITS NUMBERS WAS WRONG AS WRITTEN.** It offered five token searches said to return zero in this file and named "the five records citing SRC-417" - which was five HITS across three records mis-transcribed as five records. **Worse the token evidence is no longer reproducible**: `NAS3-22764` `SRC-336` `mylar` and `thin-film` all return hits now because and were registered the same day and contain them. A reader re-running those searches gets different answers and cannot tell whether the record is wrong or the register moved. **STATED INSTEAD AS A METHOD A DATE AND A POPULATION**: on 2026-09-15 every record whose text contains the token `SRC-417` was expanded to its whole record and read - seven such records four of them registered that same day - and none carries an efficiency-on-substrate figure. ** comes closest**: it takes three efficiency figures off the same SRC-417 viewgraph page "MAXIMUM POSSIBLE DC TO DC EFFICIENCY --- 76%" "EXPERIMENTAL DC TO DC EFFICIENCY --- 54%" and "SOLAR POWER SATELLITE EFFICIENCY --- 58-72%" and none attaches an efficiency to a substrate. **The conclusion is unchanged; only the evidence offered for it was wrong.** **So this record inoculates rather than repairs.**CLM-0940 Two NASA efforts to build rectennas at much higher frequencies than the standard 2.45 GHz ended...CLM-0941 In space there is no air to carry away the waste heat, so a rectenna's output is limited by how...CLM-0933 In 1988 the leading experimenter listed three numbers side by side: the best efficiency physics...
Cite this
energyaperture.com/c/clm-0938
CLM-0938, Energy Aperture, as of 1987.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-336
- CLM-0939The 85 per cent figure that later papers quote flat was one component on a bench, in moving air, with an error bar, at one power level. The...CLM-0940Two NASA efforts to build rectennas at much higher frequencies than the standard 2.45 GHz ended without a working device. One concluded the...CLM-0941In space there is no air to carry away the waste heat, so a rectenna's output is limited by how much waste heat it can radiate. The report...CLM-0969If the tubes are only 70 per cent efficient, the transmitter's own face is not big enough to get rid of the heat they make, even spread...