The document summarizes the development of interferometric radiometry for remote sensing from space. It describes the ESTAR project which demonstrated the viability of aperture synthesis for remote sensing applications. It outlines the hardware used by ESTAR and discusses various field campaigns involving soil moisture and ocean salinity measurements. Plans are described for a proposed spaceborne version called HYDROSTAR, and lessons learned from subsequent projects including 2D-STAR, SMEX-03, and issues dealing with radio frequency interference and noise injection stability.

1. ESTAR TO SMOS DEVELOPMENT OF INTERFEROMETRIC RADIOMETRY FOR REMOTE SENSING FROM SPACE David M. Le Vine Goddard Space Flight Center Greenbelt, MD 20771

4. ESTAR Hardware

5. Walnut Gulch Watershed ESTAR Image T B vs Soil Moisture ESTAR (Solid); PBMR (open)

7. HYDROSTAR ESTAR in Space: Proposed to First NASA ESSP Call Deployed Resolution < 30 km ( 5.8 x 9.5 m array) Deployment of Antenna (16 Slotted Waveguide Sticks)

9. 2D-STAR Installed on NASA P3-B Aircraft

10. SMEX-03: Huntsville, AL Above : Landsat, false color image of SMEX-03 site. Tennessee River at lower right. Right : 2D-STAR image during SMEX-03; H-pol (top) and V-pol (bottom)

11. Lessons Learned

12. RFI is a problem even in the restricted band at 1.413 GHz ESTAR image crossing the Chesapeake Bay near Richmond, Virginia showing effects of RFI RFI in zero spacing channel

14. ESTAR TO SMOS DEVELOPMENT OF INTERFEROMETRIC RADIOMETRY FOR REMOTE SENSING FROM SPACE David M. Le Vine Goddard Space Flight Center Greenbelt, MD 20771 C. Swift, T. Jackson, A. Tanner, C. Ruf, A. Griffis, J. Isham, P. Gaiser, M. Goodberlet , M. Haken, J. Fuchs, R. Aldridge, ProSensing Staff, M. Kao, J. Good

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