Deep space Ka-band link management and Mars Reconnaissance Orbiter: long-term weather statistics versus forecasting

During the last 40 years, deep space radio communication systems have experienced a move toward shorter wavelengths. In the 1960s, a transition from L- to S-band occurred, which was followed by a transition from S- to X-band in the 1970s. Both these transitions provided deep space links with wider bandwidths and improved radio metrics capability. Now, in the 2000s, a new change is taking place: namely, a move to the Ka-band region of the radio frequency spectrum. Ka-band will soon replace X-band as the frequency of choice for deep space communications, providing ample spectrum for the high data rate requirements of future missions. The low-noise receivers of deep space networks have a great need for link management techniques that can mitigate weather effects. In this paper, three approaches for managing Ka-band Earth-space links are investigated. The first approach uses aggregate annual statistics, the second one uses monthly statistics, and the third is based on the short-term forecasting of the local weather. An example of weather forecasting for Ka-band link performance prediction is presented. Furthermore, spacecraft commanding schemes suitable for Ka-band link management are investigated. Theses schemes will be demonstrated using NASA´s Mars Reconnaissance Orbiter spacecraft in the 2007-2008 period, and the demonstration findings will be reported in a future publication.