|GBU-53/B (Small Diameter Bomb II)|
|Place of origin||United States|
|In service||2017 (planned)|
|Used by||United States|
US$227,146 inc R&D (FY15)
|No. built||17,143 planned|
|Weight||204 lb (93 kg)|
|Length||69 in (176 cm)|
|Diameter||6–7 in (15–18 cm)|
|Warhead||105 lb (48 kg)|
|69 miles (110 km), 45 miles (72 km) against moving targets|
|Millimeter wave Active radar homing / Semi-active laser guidance / Infrared homing (using an uncooled imaging infrared camera) / GPS coupled Inertial guidance / Data Link|
Development was started in 2006 for a 250 pounds (113 kg) class bomb that can identify and strike mobile targets from standoff distances in all weather conditions. It will be integrated on the F-15E and F-35 fighters. Its first flight was announced on May 1, 2009. A contract to start low-rate production was awarded to Raytheon in June 2015.
A Boeing/Lockheed Martin team attempted to develop it but lost in a U.S. Air Force competition. Boeing won the original competition but the project was on hold for several years due to a corruption scandal involving Darleen Druyun. The competition was reopened in September 2005.
The bomb can use a GPS/INS system to guide itself into the general vicinity of a moving target during the initial search phase, with course correction updates provided using a Link 16 over UHF data link. The bomb has three modes of target acquisition: millimeter-wave radar, infrared homing using an uncooled imaging seeker, and semi-active laser homing. The weapon is capable of fusing the information from the sensors to classify the target and can prioritize certain types of targets as desired when used in semi-autonomous mode.
The shaped charge warhead in the bomb has both blast and fragmentation effects, which makes it effective against infantry, armor (including MBTs), unhardened structures and buildings, as well as patrol craft sized boats and other soft targets. The bomb would be the first purpose-built no-drive zone enforcement weapon.
The use of uncooled imaging infrared has been cited as innovative and effective in reducing costs. An important feature of the new weapon is the maximization of the number of the bombs carried by the strike aircraft. A total of 28 GBU-53/B can be carried by the F-15E Strike Eagle utilizing 7 BRU-61/A suspension units, each carrying 4 bombs, and eight bombs along with two AIM-120 AMRAAM missiles in the weapons bay of the F-22 Raptor or the F-35 Lightning II (even the STOVL F-35B). The F-35 will be able to operate the bomb until it receives the Block 4 software package in 2022. The SDB II bomb rack originally did not fit inside the smaller F-35B weapons bay. A modification will be provided to coincide with the software package.
The original Small Diameter Bomb (SDB) was developed by Boeing and made for non-moving targets. The SDB II is designed to destroy moving targets in dust and bad weather. The Raytheon version was deployed successfully in 26 missions over 21 days. Raytheon was awarded the contract in August, 2010. The North American division of MBDA continues to produce the wings. The Raytheon contract is worth US$450 million. Boeing announced that it would not protest the Raytheon award.
On July 17 2012 the SDB II successfully engaged and hit a moving target during a flight test at the White Sands Missile Range. The bomb was dropped from an F-15E Strike Eagle, then acquired, tracked, and guided itself onto a moving target using its tri-mode seeker, scoring a direct hit.
In January 2013 four SDB IIs were loaded into the weapons bay of an F-35 Lightning II alongside an AIM-120 AMRAAM missile. The successful fit check validated that the SDB II was compatible with the F-35 and gave adequate clearance in sweeps of inboard and outboard bay doors.
Two SDB IIs successfully conducted live fire tests against moving targets, one in September 2014 and the other in February 2015. Successful live fire tests qualified the weapon for the Air Force to make a Milestone C decision, leading to entering low-rate initial production (LRIP).
The SDB II received Milestone C approval in early May 2015, completing a five-year development program and clearing it for production and deployment with the F-15E. A handful of failed test shots prolonged development from four years to five, but per-unit cost was reduced from the goal of $180,000 to $115,000. Raytheon was awarded a $31 million contract on 12 June 2015 for the first LRIP lot of 144 SDB IIs.
Raytheon considered offering the SDB II to the United Kingdom for their Spear Capability 3 requirement to arm the Royal Air Force Eurofighter Typhoon and Royal Navy F-35B. To compete with MBDA's offer of a powered weapon, Raytheon considered a powered SDB II variant. In May 2016, the UK awarded a contract to MBDA to develop the SPEAR 3 missile, confirming it "as the only weapon to meet the UK’s operational requirement" and rejecting the unpowered and shorter-range SDB II.
The Republic of Korea Air Force is considering adopting the SDB II for use on its F-15K aircraft, as the bomb's capability to destroy moving targets more than 60 km away in all kinds of weather is useful to strike North Korean mobile missile launchers.
The United States Air Force plans to use the bomb on the F-15E Strike Eagles as a no-drive zone enforcement weapon. The U.S. Navy and U.S. Marines plan to use it on their versions of the F-35 Joint Strike Fighter. Delivery for the first batch is planned for late 2014. Government requirements specify a 2016 delivery date.
- DRDO Smart Anti-Airfield Weapon
- Mark 81 bomb – 250lb general purpose bomb
- Brimstone (missile) – 100lb class air to surface missile
- SPEAR 3 – a comparable air to surface missile
- AGM-154 Joint Standoff Weapon – 1000lb class glide and powered weapon by Raytheon
- Spice 250 – a comparable glide bomb
- "GAO-15-342SP DEFENSE ACQUISITIONS Assessments of Selected Weapon Programs" (PDF). US Government Accountability Office. March 2015. p. 123. Retrieved 16 July 2015.
- "GAO-13-294SP DEFENSE ACQUISITIONS Assessments of Selected Weapon Programs" (PDF). US Government Accountability Office. March 2013. pp. 101–2. Retrieved 26 May 2013.
- Small Diameter Bomb II Completes Live Fire Test Destroying T-72 Tank – Military.com, 25 February 2015
- "Air Force picks small diameter bomb". United Press International.
- "Raytheon GBU-53/B Small Diameter Bomb II Completes First Flight". Space.
- "Raytheon Wins USAs GBU-53 Small Diameter Bomb Competition". Defense Industry Daily.
- "Small Diameter Bomb II – GBU-53/B". Defense Update].
- F-35 Will Not Reach Full Close-Air-Support Potential Until 2022 – DoDBuzz.com, 10 March 2015
- "Raytheon wins USA GBU-53/B small diameter bomb competition". Defense Industry Daily.
- MBDA US Division Corporate
- Small Diameter Bomb II Successfully Hits Moving Target on the Ground – Deagel.com, July 19, 2012
- Small Diameter Bomb II Fit Check on F-35 Aircraft – Airforce-Technology.com, January 23, 2013[unreliable source?]
- SDB II undergoes live fire testing on F-15E – Flightglobal.com, 19 February 2015
- Raytheon’s Small Diameter Bomb II approved for production, deployment – Flightglobal.com, 15 May 2015
- Raytheon Wins Small Contract For Huge Program: SDB II Exports By 2018 – Breakingdefense.com, 19 June 2015
- "Contracts CR-111-15". US Department of Defense. 12 June 2015. Retrieved 2015-07-15.
- Raytheon takes aim at UK Spear deal with SDB II – Flightglobal.com, 23 July 2014
- Raytheon Considers Powered SDB for UK F-35s – Defensenews.com, 15 June 2015
- UK Confirms Development of New Spear Missile for F-35 – Ainonline.com, 19 May 2016
- South Korea plans to buy more Taurus missiles after North Korea's new nuclear test – Airrecognition.com, 4 October 2016