Rockwell Scientific Company is developing a new type of HgCdTe 1K 1K detector, called WFC3-1R, with cutoff wavelength at 1.7 m and 150K operating temperature. The detector will be installed on the Wide Field Camera 3, the fourth generation panchromatic instrument for the Hubble Space Telescope (HST) to be installed during HST Servicing Mission 4, currently scheduled for 2004. The detector uses HgCdTe MBE grown on a CdZnTe substrate and a new type of multiplexer, the Hawaii-1R MUX. Six lots of detectors have been produced so far, and have demonstrated the capability to meet or exceed the project requirements. In particular, detectors show quantum efficiency as high as ~90% at =1.4-1.6 m and greater than 50% at >1.0 m, readout noise of 30 e- rms with double correlated sampling, and dark current <0.2 e/s/pix at 150K. We illustrate the behavior of the reference pixels, showing that they allow the compensation of drifts in the dc output level. A number of detectors show a peculiar instability related to the variations of diode polarization, still under investigation. We also report on the environmental testing needed to qualify the WFC3- 1R detectors as suitable for flight on the HST. We finally provide an update of the project status.