Athena (rocket family)

Variants

The Athena I has two stages: a Thiokol Castor-120 first stage and a Pratt & Whitney ORBUS 21D upper stage, both solid-propellant. The Athena II uses three stages, with Castor-120 first and second stages and an ORBUS 21D upper stage. Planned future configurations, Athena Ic and Athena IIc, would replace the ORBUS 21D with Castor 30 stages. An Orbit Adjust Module (OAM) developed by Primex Technologies (acquired by General Dynamics in 2001) houses attitude control, avionics, guidance, batteries, telemetry, and command/destruct systems; it is 1 meter long and fueled with monopropellant hydrazine.

After payload separation, the OAM performs a contamination and collision avoidance maneuver and burns remaining fuel. Alliant Techsystems (ATK) produces integrated upper stages using spin-stabilized or 3-axis stabilized Star solid motors for GEO and escape missions; a Star 37FM was used for Lunar Prospector. An Athena III, designated LLV-3, was planned with two, four, or six Castor-4A strap-on boosters to lift 3.6 tons to low Earth orbit but was never developed due to lack of customer interest.

Launches

On August 15, 1995, an Athena-1 rocket (vehicle DLV) failed during launch when hydraulic fluid burned in the first stage aft section, damaging nozzle feedback cables and causing loss of gimbal control; arcing in the IMU high-voltage power supply also caused loss of attitude reference, and the flight was terminated at T+160 seconds. On April 27, 1999, an Athena-2 rocket (vehicle LM-005) failed because the payload fairing did not separate; the shock of the circumferential ordnance firing disconnected the cable for the longitudinal ordnance, and the extra weight prevented orbit.