 Complete the following phrase:  Note: while a TDRSS satellite is in the manufacturing process it is given a letter designation, but once it has successfully achieved the correct geosynchronous orbit it is referred to with a number for example, TDRS-A during development and before on-orbit acceptance, and TDRS-1 after acceptance on orbit and put into operational use. Thus, satellites that are lost in launch failures or have massive malfunctions are never numbered for example, TDRS-B, which was never numbered due to its loss in the 