Source: USGS Landsat Mission
Starting on Friday, March 25th, MSS orders will be held so that radiometric enhancements can be implemented. MSS processing will recommence on April 1st, and notices will be sent, as typical, when scenes are completed. For more information on these enhancements, please see the L1–5 MSS Calibration page.
Further Information:
+ “MSS orders held until April 1st,” USGS

Above the Earth, Below the Surface: Landsat’s Role in Monitoring Water Quality
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.