Launched in January, the active radar part of the 'spinning lasso' antenna attached to NASA's SMAP satellite has stopped functioning and can't be recovered. Fortunately, the space agency is still able to carry forward the near- billion-dollar mission as a radiometer instrument, the other half of the spacecraft's mission, is still working. This passive instrument is still receiving with the help of the similar lasso antenna which was used by the active instrument used.

NASA's SMAP (the Soil Moisture Active Passive observatory) is an earth-sensing mission that carried out two instruments. The first one was a six-meter mesh known as 'lasso', circling every four seconds to map soil moisture with radar signals. These entered a few centimeters into the soil. The backscatter of the returning signals indicated the soil moisture amount in areas around a mile wide at a time.

A radiometer was the passive instrument that picked up microwave signals, emitting from wet soils. When both were functioning, their measurements could be compared to each other.

Unfortunately, the radar antenna stopped the transmission of data in July and soon NASA found that there was an issue with its high power amplifier.

The ground crews took more than a month to identify the problem and reproduced it in laboratories. They attempted to re-start the unit on August 24 but failed.

That was the time when the space agency realized that the antenna can't be repaired and they have to carry forward the mission using the passive collector.