SAR/radar for cubesat, membrane reflectarray antenna

[NirViaje]

LISA-T

• https://github.com/ExponentialDeepSpace/eds-archive/issues/39

SRI-CubeSat Imaging Radar for Earth Science (SRI-CIRES)

• https://esto.nasa.gov/forum/estf2015/presentations/Wye_S6P8_ESTF2015.pdf

• https://esto.nasa.gov/forum/estf2016/PRESENTATIONS/Wye_A7P3_ESTF2016.pdf

[NirViaje]

• http://120.52.51.18/www.unoosa.org/documents/pdf/psa/activities/2017/SouthAfrica/slides/Presentation23.pdf

• https://earth.esa.int/documents/1656065/1664726/15-TDS_NovaSAR.pdf

[NirViaje]

Radio Frequency Risk Reduction Deployment Demonstration (R3D2)

The R3D2 prototype array, packed inside a 330lb (150kg) satellite, includes a tissue-thin Kapton membrane antenna designed to expand to a size of 7.4 feet (2.25 meters) once in orbit. DARPA said the antenna could help provide high data rate communications to disadvantaged users on the ground. The agency said the satellite design, development, and launch took approximately 18 months.

Northrop Grumman is the prime contractor on the satellite, MMA Design designed and built the antenna, Trident Systems designed and built R3D2’s software-defined radio, and Blue Canyon Technologies provided the spacecraft bus.

• https://www.bgp4.com/2019/01/24/darpas-r3d2-array-radio-frequency-risk-reduction-deployment-demonstration-satellite/

Our Radio Frequency Risk Reduction Deployment Demonstration (R3D2) is set for #launch in late February to space-qualify new type of membrane reflectarray antenna. Made of a tissue-thin Kapton membrane, antenna deploys to 2.25 meters diameter once in LEO. https://go.usa.gov/xEZux

• https://www.darpa.mil/news-events/2019-01-22b

DaHGR Mechanical Performance

• Areal Compaction: approximately {0.5 to 1.0} m2/L
• Mass Density: {1.5 to 1.0} kg/m2 @10m2 to {1.6 to 1.0} kg/m2 @0.78m2
• First mode >1 Hz
• Low CTE structure
• On orbit adjustable feed to reflectarray geometry

Frequency Range and Bandwidth for Small Sats

• Aperture sizes in development span 0.8 m to 5 m diameter

• Lower frequency limited by electrical size conducive to spatial feeding with minimal spillover losses (~D/λ > 10)

  • D=5m, λ=0.5m, lowest frequency is 0.6 GHz
  • At smaller electrical size, the deployment methods described support constrained feed antenna architectures.

• Highest frequency is limited by features controlling deployed flatness and allowance for Gain and sidelobe degradation

• Reflectarrays are inherently band width limited

• https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=3387&context=smallsat

• https://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=0&article=3387&context=smallsat&type=additional

[NirViaje]

• Review of Large Spacecraft Deployable Membrane Antenna Structures, CAST5, 2017

• Reflectarray Membrane Study for Deployable SAR Antenna, DLR, 2009

• Experimental and Analytical Studies of a Large In-Space Deployable Dual-Band Membrane Reflectarray Antenna, JPL, 2007
• Inflatable Microstrip Reflectarray Antennas At X and Ka-Band Frequencies, JPL, 1998

[NirViaje]

https://github.com/ExponentialDeepSpace/exponentialdeepspace.github.io/issues/35#issuecomment-445857015

Optical membrane

Membrane optics is a flat lens that employs plastic in place of glass to diffract rather than reflect or refract light. Concentric microscopic grooves etched into the plastic provide the diffraction.[1]

Glass transmits light with 90% efficiency, while membrane efficiencies range from 30-55%. Membrane thickness is on the order of that of plastic wrap.[1]

• https://en.wikipedia.org/wiki/Optical_membrane
• Membrane Optical Imager for Real-Time Exploitation (MOIRE)
• https://en.wikipedia.org/wiki/Zone_plate

• Photon Sieve Space Telescope, USAF Academy, 2010_Andersen.pdf

Diffractive Fresnel Lens

• nautilus-array,
• Multiple Order Diffractive Fresnel Lens (MOD-DFL) for Atmospheric Transit Surveying of Earthlike Exoplanets, 2017
• 微结构薄膜望远镜研究进展分析, CAS, 2017
• 聚酰亚胺薄膜透镜制备关键技术研究
  • 一种制备连续面形菲涅尔透镜的方法
• 用于空间望远镜的膜光子筛

• 空间衍射望远镜自展开结构设计, 中国科学院长春光学精密机械与物理研究所, 2017