Large SAR Membrane Antennas with Lightweight Deployable Booms
Bibliographic record
Abstract
At the DLR Institute of Composite Structures and Adaptive Systems and the company Kayser-Threde extremely lightweight and stiff deployable carbon fibre-reinforced plastics (CFRP) booms and deployment mechanisms have been developed. The main target application is to develop an ultra-light weight solar sail for deep space satellite propulsion. Based on the successful development and ground-testing of a 20m x 20m deployable solar sail structure the in-orbit verification of the deployment principle and mechanisms is now being planned for launch in 2007. Kayser-Threde in collaboration with DLR has most recently completed a phase-B study of the solar sail project under ESA/ESTEC contract. In addition, mission and design studies have been performed at Kayser-Threde for ultra-light weight structures which can reach 100m x 100m in free space where a reflective, thin polyimide membrane is unfolded using DLR's advanced CFRP booms. Synthetic Aperture Radar (SAR) satellites require large and long antennas which in turn require a large satellite bus as well as a launcher with a large fairing. This is especially true for lower frequency SARs such as L-Band, where antenna sizes of typically 12m x 3m are required. The cost for such a SAR mission could be reduced significantly if the antenna and its deployment and support structure would be lightweight and could be folded during launch. The membrane antenna concept has been demonstrated in Canada by the CSA and EMS Technologies, and in the US by JPL. Receive only antennas are of interest for micro satellites which fly in a formation with a large active SAR satellite in order to perform SAR interferometry in a "Cartwheel" configuration. However, research has also been done for active phased array membrane antennas. The paper provides a first concept for a deployment and support structure for a L-Band SAR membrane antenna. Estimates for the mass and the achievable stiffness are provided.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".