Session
Flash Talks Session 1
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
Spacecraft conducting signals intelligence (SIGINT) missions require highly capable radio-frequency (RF) payloads. While the larger 80 kg-class platforms offer increased payload capacities, strict internal volume limitations persist. These constraints sometimes require stowing instruments, such as the dual-monopole Very High Frequency (VHF) antenna presented in this work, directly beneath the solar wings. This requirement has imposed a strict height constraint on the VHF antenna, mandating a highly compact and reliable deployment mechanism that avoids snagging or jamming during deployment.ย
This paper presents the mechanism design and qualification test plan of a novel, deployable dual-monopole VHF antenna system designed to increase satellite SIGINT capabilities. The antenna consists of two stainless steel tape springs tuned to the VHF frequency band. To meet volume requirements, the antenna elements are rolled and stowed beneath a retention door machined from RF-transparent Polyether Ether Ketone (PEEK). The door is secured using a micro-latch actuated by a shape memory alloy (SMA).ย
During development, a conflict was identified between the radial swing of the PEEK door and the axial release requirement of the micro-latch, resulting in the mechanism jamming during deployment. To prevent the micro-latch coupler nut from binding to the fixed release stem, a modified deployment sequence was engineered. Upon SMA actuation, a dedicated set of nested wave springs was implemented to pull the release nut axially, clearing the fixed micro-latch stem and decoupling the radial motion of the PEEK door from the axial motion of the micro-latch. Mathematical modelling of the mechanism was conducted and predicted that the implementation of these wave springs would successfully decouple the radial and axial motions. To empirically verify the design, deployment testing was conducted on a 3D-printed prototype of the VHF antenna. Slow-motion camera footage confirmed that the deployment sequence operates as intended, allowing the tape springs to deploy reliably.ย
To qualify this mechanism for flight, a test campaign has been defined. Structural integrity will be verified through quasi-static load testing and random vibration testing to ensure the mechanism survives the launch environment without material damage or premature deployment. Thermal vacuum (TVAC) testing and rough vacuum deployments will be conducted to ensure the mechanism operates reliably in the space environment. Deployments will be conducted before, during, and after TVAC to ensure the design functions properly throughout the test campaign. Finally, radiofrequency (RF) performance will be experimentally measured via ๐11 return loss measurements across multiple element orientation angles, ensuring the system meets a maximum -10 dB return loss. Ultimately, this work presents a newly designed deployment mechanism and a comprehensive test campaign, providing a framework for integrating complex RF instruments within highly constrained microsatellite envelopes.
Document Type
Event
Included in
Design and Qualification of a Compact, Deployable Dual-Monopole Antenna System for Remote Sensing Microsatellites
Salt Palace Convention Center, Salt Lake City, UT
Spacecraft conducting signals intelligence (SIGINT) missions require highly capable radio-frequency (RF) payloads. While the larger 80 kg-class platforms offer increased payload capacities, strict internal volume limitations persist. These constraints sometimes require stowing instruments, such as the dual-monopole Very High Frequency (VHF) antenna presented in this work, directly beneath the solar wings. This requirement has imposed a strict height constraint on the VHF antenna, mandating a highly compact and reliable deployment mechanism that avoids snagging or jamming during deployment.ย
This paper presents the mechanism design and qualification test plan of a novel, deployable dual-monopole VHF antenna system designed to increase satellite SIGINT capabilities. The antenna consists of two stainless steel tape springs tuned to the VHF frequency band. To meet volume requirements, the antenna elements are rolled and stowed beneath a retention door machined from RF-transparent Polyether Ether Ketone (PEEK). The door is secured using a micro-latch actuated by a shape memory alloy (SMA).ย
During development, a conflict was identified between the radial swing of the PEEK door and the axial release requirement of the micro-latch, resulting in the mechanism jamming during deployment. To prevent the micro-latch coupler nut from binding to the fixed release stem, a modified deployment sequence was engineered. Upon SMA actuation, a dedicated set of nested wave springs was implemented to pull the release nut axially, clearing the fixed micro-latch stem and decoupling the radial motion of the PEEK door from the axial motion of the micro-latch. Mathematical modelling of the mechanism was conducted and predicted that the implementation of these wave springs would successfully decouple the radial and axial motions. To empirically verify the design, deployment testing was conducted on a 3D-printed prototype of the VHF antenna. Slow-motion camera footage confirmed that the deployment sequence operates as intended, allowing the tape springs to deploy reliably.ย
To qualify this mechanism for flight, a test campaign has been defined. Structural integrity will be verified through quasi-static load testing and random vibration testing to ensure the mechanism survives the launch environment without material damage or premature deployment. Thermal vacuum (TVAC) testing and rough vacuum deployments will be conducted to ensure the mechanism operates reliably in the space environment. Deployments will be conducted before, during, and after TVAC to ensure the design functions properly throughout the test campaign. Finally, radiofrequency (RF) performance will be experimentally measured via ๐11 return loss measurements across multiple element orientation angles, ensuring the system meets a maximum -10 dB return loss. Ultimately, this work presents a newly designed deployment mechanism and a comprehensive test campaign, providing a framework for integrating complex RF instruments within highly constrained microsatellite envelopes.
