Athena

Lockheed Martin * ATK Thiokol Propulsion * Pratt & Whitney

Athena was developed commercially by Lockheed Martin to address the market for delivering small spacecraft to LEO. The Athena family includes two small launch vehicles, the three-stage Athena I (syn. LMLV-1) and the four-stage Athena II. Both vehicles are made up of solid motors and a small liquid injection stage, called the Orbit Adjust Module (OAM). The vehicles are modular, and the Athena II shares all the components of Athena I with the addition of an extra Castor-120 solid motor. The Athena I preceding version is the LLV-1, developed by Lockheed based on a Peacekeeper first-stage.

The Castor-120 is a commercial SRM developed by Thiokol. It is a derivative of the Peacekeeper ICBM first stage motor TU-903. It has  the same diameter as the PK, but is 35 in. longer to include more propellant. The  casing is filament-wound graphite-epoxy composite, and TVC is provided by a new blowdown hydraulic nozzle gimbal system.
The Pratt & Whitney's Orbus-21D motor is derived from the Orbus-21 motors used in the IUS and TOS upper stage for the Titan. For the future missions Lockheed Martin will upgrade to the Orbus-21G motor, which has a lightweight graphite-epoxy motor casing in place of the current Kevlar case.
The OAM is a small, monopropellant hydrazine stage that provides precise orbit injection. Axial propulsion is provided by four small 220 N thrusters around the circumference of the stage. The  OAM is available with four or six propellant tanks. The tanks are mounted in pairs in an egg-crate frame structure inside the stage.
The standard fairing is the Model 92 (diameter 92 in.) with a 7.6 ft. length.

Lockheed Martin and Alliant Techsystems (ATK) will attempt to resurrect the long-dormant Athena series of small-satellite launchers under an arrangement.
The upgraded Athena Ic and Athena IIc rockets will feature the same Castor-120 solid rocket motors as their predecessors, but use the newly developed Castor-30 motor for their upper stage. The original Athena vehicles used the Orbus-21D motor built by the former Chemical Systems Division of United Technologies Corp. The new Athena vehicles will starting in 2012 (not realized up to now).
Lockheed Martin and Alliant Techsystems (ATK) now plans to build a further Athena IIcS with 2, 4 or 6 strap-ons Orion 50SXLG. It will be launched from Kodiak.

Castor-120XL
This variant of the Castor-120 predecessor is used as a first or second stage in commercial launch vehicles and provides improved performance over the baseline configuration. A version of this motor was static tested for the U.S. Air Force as part of the Large Class Stage development program, however the motor is being updated to tailor burn rates and improve performance, as well as utilize common materials & processes to improve cost control for launch vehicle providers.
In addition to Athena family, Castor 120XL is also in preparation for Minotaur-C (ex-Taurus family) and Minotaur-I Commercial version which are in the process of being merged into one sub-family under Minotaur-I.