Moving Target: Raytheon’s GBU-53 Small Diameter Bomb IIJan 23, 2013 12:07 UTC by Defense Industry Daily staff
The 250 pound GBU-39 Small Diameter Bomb gives American fighters the ability to carry more high-precision GPS-guided glide bombs, without sacrificing punching power against fortified targets. The initial award to Boeing was controversial, and the Darlene Druyun corruption scandal ultimately forced a re-compete of the Increment II development program. Whereas the initial GBU-39 SDB-I offered GPS-guided accuracy in a small and streamlined package, the goal of the GBU-53 SDB-II competition was a bomb that could hit moving targets in any weather, using a combination of guidance modes.
For the SDB-II competition, Boeing found itself allied with Lockheed Martin, its key opponent for the initial SDB-I contract. Its main competitor this time was Raytheon, whose SDB-II bid team found itself sharing its tri-mode seeker technology with a separate Boeing team, as they compete together for the tri-service JAGM missile award against… Lockheed Martin. So, is Raytheon’s win of the SDB-II competition also good news for its main competitor? It’s certainly good news for Raytheon, who wins a program that could be worth over $5 billion.
Raytheon’s GBU-53 Small Diameter Bomb
Raytheon’s GBU-53/B SDB-II is 7″ in diameter around the tri-mode (laser, IIR, radar) seeker, with a clamshell protective door that comes off when the bomb is dropped. A GPS receiver adds a 4th targeting mode. The bomb tapers to about 6″ diameter beyond the pop-out wings, and is about 69.5″ long. The wings remain swept back when deployed, and are about 66″ across with a 5 degree anhedral slope. The bomb weighs about 200 pounds, and all of these dimensions are important when trying to ensure that the US Marines’ F-35B, with its cut-down internal weapon bays, can still carry 8 of them per bay. It also fits on BRU-61 external bomb racks.
Range is expected to be up to 40 nautical miles when launched at altitude, thanks to a high lift-to-drag ratio in the design. Since SDB-II is an unpowered glide bomb, its actual range will always depend on launching altitude and circumstances. While an F-22A would be able to extend that range significantly by launching at supercruise speeds of Mach 1.5+, there are currently no plans to add SDB-II to the Raptor’s JDAM and SDB-I strike options.
SDB-II’s Attack Modes: Seekers & Sequences
Once a target is picked by the pilot, initial communication and GPS coordinates are transmitted between the aircraft and the SDB-II bomb using the Universal Armament Interface (UAI) messaging protocol, which was designed to make integration of new weapons easier. The post-launch datalink will be Rockwell Collins’ TacNet, a 2-way, dual band link that enters the network quickly using encrypted UHF radio frequencies from the ground or secure Link-16 from the launching aircraft, and provides both weapon and target status to the shooter. TacNet’s datalink software is programmable if other frequencies/waveforms need to added in future, and Raytheon cites a message speed of 38 messages per minute as further evidence of the system’s ability to keep pace with future needs. Link-16 makes the weapon part of a much larger system, and gives SDB-II the ability to be dropped by one platform and then targeted or re-targeted by another. The bomb can also be sent an abort command, if necessary. If the link is lost, the bomb will continue with its mission, using its own on-board seekers.
Raytheon’s SDB-II contender uses a close precursor of the tri-mode seeker technology featured in the joint Raytheon/Boeing bid for the JAGM missile, which adds some refinements. The SDB-II uses jam-resistant GPS/INS targeting like Boeing’s GBU-39 SDB-I, but its added seeker features 3 modes of operation: semi-active laser, millimeter-wave radar, and uncooled imaging infrared. By combining these 3 modes, the GBU-53 can have excellent performance against a variety of target types, under any weather conditions, while making it much more difficult to use countermeasures or decoys successfully:
Semi-active laser guidance. This is standard for a wide range of missiles and rockets, and offers the best on-target accuracy and assurance, especially in urban environments. Its flip side is problematic performance in heavy fog, sandstorms, etc. That’s where the 2 fire-and-forget modes, plus GPS/INS guidance, come in.
Millimeter wave radar will operate through any weather. It’s especially good at distinguishing metal targets and noting movement, and is used in weapons like AGM-114 Hellfire Longbow missiles to give them “fire and forget” capability. These days, most people probably know the technology from airport scanners.
Imaging infrared (IIR) This was adapted from the much larger AGM-154 JSOW glide bomb, and uses high-resolution thermal scans to create a target picture. It also helps with target identification, and offers better performance against some kinds of targets like humans. By using an uncooled IIR seeker, the bomb lowers both its cost and its maintenance requirements. The uncooled seeker also allows snap-attacks against targets that present themselves quickly, since the it doesn’t need any time to cool down before it begins to work.
Once launched, the SDB-II relies on a sophisticated package of internal computing and algorithms that are designed to get the most out of its tri-mode sensors, and make the process of launch and targeting as simple and flexible as possible for the pilot. The GPS/INS system or datalink messages guide the bomb toward the target during the initial search phase, while the tri-mode seeker gathers initial data. A revisit phase combines information from all of its sensor modes to classify targets. That’s especially useful because the SDB-II can be told to prioritize certain types of targets, for example by distinguishing between tracked and wheeled vehicles.
Different targets require different warhead types, which is why the GBU-53 contains a warhead from General Dynamics Ordnance & Tactical Systems that delivers shaped charge, blast and fragmentation effects all at once. A scored blast and fragmentation warhead makes it deadly against buildings and people as well.
This warhead was actually redesigned mid-way through the development phase, as the USAF added a requirement to take out main battle tanks. That initial hardship became a positive experience, as the redesign ended up shrinking Team Raytheon’s bomb’s size, and improving its manufacturing costs.
SDB-II: The Program
The overall program target for SDB-II is about 17,000 weapons: 12,000 for the USAF, and 5,000 for the US Navy. Initial fielding will take place on USAF F-15E Strike Eagles, and F-35B/C Block 4s of the US Marine Corps and Navy. Likely candidates for future fielding include Navy F/A-18 E/F Super Hornets; USAF A-10C close air support fighters, F-16, F-22A, and F-35A fighters; B-52, B-1B, and stealth B-2A bombers; and even MQ-9 Reaper drones.
It may also feature integration with other fighters, if the bombs are sold abroad. Raytheon is not currently talking to any foreign buyers, however, and doesn’t foresee the US government releasing it for sale before Low-Rate Initial Production begins in late 2013.
Elements of the SDB-II design have been tested, but putting the entire weapon together with its carrying aircraft and declaring the combination ready for fielding is still a development effort. Although many military development efforts are “cost-plus” (contractor’s costs plus an agreed percentage), the US military issued the SDB-II EMD Phase development contract as a fixed-price contract with incentives. The targeted flyaway cost per unit during Full Rate Production is $FY05 62-81k, which does not include amortized development costs, but does include the bomb, container, and shipping.
As things currently stand, GBU-53 Low-Rate Initial Production could finish in 2016 with LRIP Lot 4, at about 1,000 weapons delivered. The question is whether the F-35 program, which has seen its own development program stretched from a 2013 finish to 2019, will be ready. If it isn’t, the Small Diameter Bomb Increment II program may face funding and production freezes, unless a different platform like the Super Hornet is added in the F-35′s stead.
Right now, the key challenge is making it through the development process successfully. The program is progressing well, but hit a FY 2011 funding shortfall from Congress that is jeopardizing its progress.
Raytheon’s Industrial Approach
Before it won the SDB-II development contract in 2010, Raytheon had secured firm-fixed price quotes in for 90% of required materials from its suppliers, and conducted detailed planning for whole program that includes reservations for setbacks and project margins. These are necessary steps for any fixed-price development program, but it’s often the work done before those contracts are signed that determines a program’s fate.
In terms of the industrial team, Raytheon Missile Systems in Tucson, AZ will be the final assembly center, with key items and assemblies coming in from several supply-chain partners:
- General Dynamics OTS: Fuze and dual-mode shaped charge blast/fragmentation warhead
- Klune Industries: Overbody
- Rockwell Collins: TacNet dual-band (Link-16, UHF), 2-way datalink
- Raytheon Dene at NAPI, NM: Aft section
- Raytheon Missile Systems in Tucson, AZ: Tri-mode seeker
- The program also uses Goodrich and Cobham to make the bomb’s deployment mechanisms, and Celestica will be manufacturing circuit cards.
Raytheon executives said that they took a somewhat different supply-chain approach to the SDB-II, picking suppliers early and then working directly with them to improve productivity at every step. While Raytheon prototyped their final assembly line, and began using lean production techniques to reduce the amount of “touch labor” and improve productivity, they brought in suppliers to do the same thing. For instance, Celestica engineers were embedded with the team, in order to run their own producibility tools on circuit card designs and refine them to improve yield and costs. Rockwell Collins, who makes the datalink, did the same thing. This is not uncommon in general manufacturing, but defense manufacturing has traditionally been more stovepiped.
Within Raytheon itself, another key industrial choice involved the uncooled infrared seeker. As noted above, uncooled infrared has lower performance than cooled infrared designs, in exchange for snap-attack capability, better reliability, and lower production and maintenance costs. If Raytheon wanted to use this aproach, they would have to begin early, and take a risk. Their engineers worked to adapt the IIR seeker in their 2,000 pound AGM-154 JSOW as a starting point, and they did eventually produce a version that fit SDB-II, was cheaper to manufacture, and more than met government requirements.
Raytheon’s initial team during development will be about 300, but this is expected to drop below 50 for production phase – in part because Raytheon has already used lean techniques, and focused from the beginning on creating a design that was simpler to manufacture.
Contracts and Key Events
FY 2012 – 2013
Cheaper than expected; F-35 is biggest risk; Testing.
The weapons seemed to have adequate space, though flight testing will be needed to be sure. The F-35B will be a more challenging test, because its internal bay is smaller.
July 17/12: Testing. An F-15E Strike Eagle flying over White Sands Missile Range, NM launches a GBU-53/B, which successfully engages and hits a moving target using its tri-mode seeker. Raytheon.
March 30/12: GAO Report. The US GAO tables its “Assessments of Selected Weapon Programs” for 2012, which include the GBU-53. Overall, the GAO sees good progress, with 97% of design drawings releasable by the 2011 Critical Design Review, and serious efforts to achieve manufacturing maturity before production. As with any early stage EMD program, however, risks remain. The biggest may be Congressional management of weapons procurement:
“A postdesign review identified several risks related to weapon effectiveness verification, target classification, seeker reliability, and JSF [F-35B/C Block 4] integration. The program office is working to address each of these risks… However, the program’s biggest risk – integration with the JSF – will not be resolved until after [low-rate initial] production begins… The SDB II program office is managing a $53 million funding shortfall in fiscal year 2011, which could have programmatic and contractual implications. The SDB II contract is an incrementally funded, fixed-price incentive contract, and program officials stated that the funding shortfall could mean that the next part of the work will have to be deferred or the contract will need to be renegotiated or terminated.”
March 30/12: SAR shows success. The Pentagon’s Selected Acquisitions Report ending Dec 31/11 includes the SDB-II, and validates many of Raytheon’s releases:
“Small Diameter Bomb Increment II (SDB II) – Program costs decreased $994.1 million (-19.1%) from $5,206.6 million to $4,212.5 million, due primarily to a decrease in the estimate to reflect actual contract pricing (-$994.3 million).”
That’s 23.6% less than the baseline estimate, a very impressive achievement for any weapons program.
Nov 16/11: Testing. Raytheon says that things are going very well for the SDB-II’s warhead, and the entire program is on cost and ahead of schedule:
“After building the test warheads on the production line, engineers put the warheads through an accelerated conditioning regime equivalent to 500 flight hours and 20 years of aging in a bunker, followed by live detonation testing… [It] performed at twice what was required…”
Nov 8/11: Industrial. Raytheon announces that its engineers have used design changes and other improvement approaches to cut the time for building SDB-II uncooled tri-mode seekers almost in half, from more than 75 hours to 40 hours. This is part of Raytheon’s efforts to meet their promised prices.
FY 2010 – 2011
Raytheon wins; Program baseline set; Early industrial work & tests.
Aug 16/11: Industrial. Raytheon announces that they’ve built their 5th GBU-53 tri-mode seeker in its new automated factory, which is dedicated to tri-mode seekers. That specialization may be helpful to other programs as well. Tom White, Raytheon’s SDB II program director, says that:
“Building integrated tri-mode seekers is much more complicated than just putting together three unrelated sensors, and our fifth build proves Raytheon is the only company with the technical expertise to manufacture [them]… We’re meeting predicted component build times, and as we continue to mature the program, we will find other efficiencies and cost savings we will pass on to the customer.”
Aug 8/11: Testing. Raytheon says that a series of laboratory tests on the SDB-II’s tri-mode seeker “demonstrated that it exceeds anticipated performance parameters.” Good job.
July 28/11: Support. Raytheon Missile Systems in Tucson, AZ receives a maximum $70 million firm-fixed-price contract to provide Small Diameter Bomb II technical support. The AAC/EBMK at Eglin Air Force Base, FL manages the contracts (FA8672-11-D-0107).
April 4/11: CDR. Raytheon announces that the SDB II program completed a USAF critical design review (CDR), clearing the way for the weapon to begin captive flight testing later in 2011.
Nov 15/10: SAR Baseline. The Pentagon releases its Selected Acquisition Report for the September 2010 reporting period. With respect to SDB-II, the total expected program cost is listed as $5.21 billion, if it continues through planned production:
“This was the initial SAR following Milestone B approval authorizing the program to enter the engineering manufacturing and development (EMD) phase in August 2010. The EMD phase contract was awarded to Raytheon Missile Systems for $450.8 million. [The gating decision for] Low Rate Initial Production (Milestone C) is planned for August 2013.”
Nov 2/10: Sub-contractors. Rockwell Collins announces what Raytheon had already confirmed: its TacNet datalink will be part of the GBU-53.
Rockwell Collins’ TacNet data link system is a small form factor, dual-channel, 2 waveform terminal that enables in-flight target updates, retargeting, weapon handover coordination, bomb hit assessments and better cooperation with other networked platforms.
Aug 9/10: Contract. Raytheon Missile Systems in Tucson, AZ receives a $450.8 million contract to cover the GBU-53/B Small Diameter Bomb Increment II program’s engineering and manufacturing development phase. Delivery is expected to begin in 2013, with a required availability date in late 2014.
At first, the SDB-II will be integrated on the USAF’s F-15E Strike Eagles, the US Marines’ F-35B, and the US Navy’s F-35C aircraft. The F-35Bs should just be entering service by 2013, but the F-35Cs aren’t expected to enter service until after SDB-II deliveries begin. Raytheon Missile Systems president says that their design “fully meets the load-out requirements for all versions of the fifth generation F-35 Joint Strike Fighter’s internal weapon bays.” SDB-II integration is also expected to extend to other USAF and US Navy aircraft and UAVs over time. At this time, $23.5 million has been committed by the Miniature Munitions AAC/EBMK at Eglin AFB, FL (FA8672-10-C-0002).
During the fly-off’s technical demonstration program, Raytheon had to prove that its compact tri-mode seeker could seamlessly transition between guidance modes, and demonstrate claimed performance and reliability. Raytheon says that their GBU/53-B seeker flew 26 missions in 21 days, without a single hardware failure. Raytheon.
Raytheon wins EMD Phase
FY 2009 and Earlier
Protest derails; New early-phase awards; Big design changes.
2008: Design shifts. Mid way through the 38-month risk reduction program, Team Raytheon is faced with challenges on 2 fronts. One challenge was the need to carry 8 SDB-II bombs in the cut-down internal bomb bay of the F-35B STOVL (Short Take-Off, Vertical Landing) fighter. That meant the weapon had to become shorter, always a challenge when space is at a premium. The second challenge came from the USAF, which wanted a weapon that could disable main battle tanks. That meant the blast & fragmentation warhead the team had begun with wasn’t going to work.
In response, GD OTS started work on an innovative ‘multi-effects’ warhead. It would use a shaped charge plasma jet to kill tanks, and a scored case design improved fragmentation effects to the point that USAF engineers reportedly dubbed it “the shredder.” Meanwhile, seeker electronics had to be repackaged in a way that provided a clear path for the plasma jet. As it happens, the warhead and seeker changes allowed the bomb to become shorter, and the seeker changes made it easier and cheaper to manufacture. Raytheon would go on to win the competition. Aviation Week.
April 17/06: Contracts. The Headquarters Air-To-Ground Munitions Systems Wing at Eglin Air Force Base, FL awards 2 cost-plus fixed-fee R&D contracts under the Small Diameter Bomb (SDB) Increment II, 42-month Risk Reduction Phase. The purpose of the Risk Reduction phase is to define and validate a system concept that meets the performance requirements outlined in the SDB II System Performance Specification. Successful tests with modified JDAM recently, and weapons like Israel’s Spice GPS/INS/EO “scene-matching” bombs, strongly indicate that success is possible. Solicitations began December 2005, negotiations were complete in March 2006, and work will be complete in October 2009. The 2 winners will be competing for selection in 42 months as the prime contractor for the SDB II program, which has a potential value of $1.3-1.7 billion.
Boeing subsidiary McDonnell Douglas in St. Louis, MO receives a $145.8 million contract (FA8681-06-C-0151). This is actually a Boeing/Lockheed venture as of October 2005; prime contractor Boeing will supply the weapon and data link system, while principal supplier Lockheed Martin provides the multi-mode seeker that lets it hit moving targets. That leaves Boeing’s original Small Diameter Bomb partner, Northrop-Grumman, out in the cold.
Raytheon Co. in Tucson, AZ received its own $145.8 million contract (FA8681-06-C-0152), and is competing on its own.
Risk Reduction Phase
Feb 18/05: GAO protest. The Congressional Government Accountability Office (GAO) sustains Lockheed Martin’s protest. It finds that Darlene Druyun had played a role in the bid process that led to changes in the bomb’s technical requirements, and the deletion of related evaluation criteria. The GAO recommends a re-opened competitive procurement for the program’s $1.7 billion second phase, which had previously been awarded to Boeing and Northrop-Grumman along with SDB-I.
In September 2005, the USAF decided to re-open the Small Diameter Bomb Increment II competition. Increment II was originally awarded to Boeing and Northrop-Grumman as part of the overall SDB award.