Lockheed Martin Space Systems has delivered a missile warning satellite to the U.S. Air Force and completed ground testing of a communications satellite for the U.S. Navy, the Sunnyvale, Calif.-based company said in separate announcements.

In both cases, the satellites are the second of a series.

In a Jan. 15 press release, Lockheed Martin said it had delivered the second dedicated Space Based Infrared System (SBIRS) missile warning satellite to Cape Canaveral Air Force Station, Fla., in preparation for a March launch aboard a United Launch Alliance Atlas 5 rocket. The first dedicated SBIRS satellite was launched in May 2011 but has yet to be declared operational by the Air Force, representing an on-orbit test and checkout period whose length is unusual even by military spacecraft standards.

SBIRS will consist of four dedicated satellites in geosynchronous orbit plus sensors hosted aboard classified satellites in highly elliptical orbits. Prime contractor Lockheed Martin’s current SBIRS contract covers four dedicated satellites and long-lead items for two more; four elliptical-orbit infrared sensors; and the ground segment.

In a Jan. 16 press release, Lockheed Martin said it had completed ground-based testing of the second Mobile User Objective System (MUOS) communications satellite for the Navy and placed the spacecraft in storage. The satellite is scheduled for launch in July from Cape Canaveral.

The MUOS system will consist of four satellites in geostationary orbit providing communications to mobile forces including ships at sea and troops operating in hard-to-reach areas such as beneath forest canopies. The first of those satellites was successfully launched in February 2012.

Lockheed Martin previously announced it had completed development of a new radio frequency wave form that will enable users to leverage the full capabilities of the MUOS design once the second satellite is operational on orbit.