James Webb Space Telescope: L2 communications for science data processing

The James Webb Space Telescope (JWST) is the first NASA mission at the second Lagrange point (L2) to identify the need for data rates higher than 10 megabits per second (Mbps). The JWST will produce approximately 235 gigabits (Gb) of science data every day. In order to get this data downlinked to the Deep Space Network (DSN) at a sufficiently adequate date rate, a Ka-band 26 gigahertz (GHz) frequency (as opposed to an X-band frequency) will be utilized. To support the JSWT's utilizations of Ka-band, the DSN is upgrading its infrastructure. The range of frequencies in the Kaband is becoming the new standard for high data rate science missions at L2. Given the Ka-band frequency range, the issues of alternative antenna deployment, off-nominal scenarios, NASA implementation of the Ka-band at 26 GHz, and navigation requirements will be discussed in this paper. The JWST is also using the Consultative Committee for Space Data Systems (CCSDS) standard process for reliable file transfer using CCSDS File Delivery Protocol (CFDP). For the JWST mission, the use of the CFDP protocol enables level zero processing at the DSN site. This paper will address NASA implementation of ground stations in support of Ka-band 26 GHz and lessons learned from implementing a file based protocol (CFDP).