The E-8 Joint Surveillance Target Attack System (J-STARS) was developed by prime contractor Grumman (now Northrop Grumman) and made a 'star' debut in 1991 during Operation Desert Storm long before it was considered operational.
Based on the airframe of a Boeing 707-300 airliner, the E-8 provides the kind of capability for monitoring and controlling the land battle that the E-3 provides for the air battle. The E-8's primary mission system is the AN/APY-3 multi-mode side-looking radar whose antenna is housed in a large ventral canoe fairing. The radar allows the onboard controllers to monitor the positions and movements of all ground vehicles, as well as serving other functions. It can also differentiate between wheeled and tracked vehicles.
The two E-8A prototypes were deployed during Desert Storm, but now serve purely in the training role. The USAF's operational variant is the E-8C and this is responsible for ground surveillance, targeting, attack and battlefield management as well as bomb damage assessment. The E-8's communications and electronics systems also have a role in suppression of enemy air defense and the detection of elusive ground targets such as mobile missile launchers.
The USAF's E-8Cs are being progressively improved through staged upgrades; by 2006 the Block 50 upgrade was undertaken. It added a new AN/APY-X radar with new capabilities such as automatic target recognition, helicopter detection and tracking, electronic intelligence gathering, and maritime detection.
By the year 2000 the USAF had ordered a total of 14 E-8Cs and ultimately intends to procure 19 aircraft. The eight operational examples serve with 93rd Air Control Wing at Robins air force base, Georgia. The USAF is considering the re-engining of its E-8C fleet with CFM56 powerplants.
In 1999 a team of Raytheon and Bombardier was chosen to provide the systems and platform to fulfil the RAF's ASTOR (Airborne Stand-Off Radar) requirement. ASTOR is similar to J-STARS and had to become operational by 2004. ASTOR incorporates certain features destined for future J-STARS use that make it more capable than the contemporary standard US E-8s.