Boeing has secured a $289m contract modification from Nasa to build a Tracking and Data Relay Satellite (TDRS)-M.

The TDRS satellites incorporate steerable, single-access antennas, which can simultaneously transmit and receive at S-band and either Ku-band or Ka-band, supporting dual independent, two-way communication.

Boeing is currently building two satellites, TDRS-K and TDRS-L, under a $700m contract awarded by Nasa in 2007.

Boeing said that its three TDRS satellites are currently providing services to Nasa and two TDRS satellites are on schedule for delivery to Nasa, with launches planned for 2012 and 2013.