Ракета MBDA SPEAR 3

MBDA is developing a family of weapons from its novel Spear 3 network-enabled standoff missile.

The multinational European missile-maker sees potential in further derivatives, now that development of the weapon—designed so that four will fit in each of the Lockheed Martin F-35’s two internal weapons bays—is well-advanced. One derivative could act as an electronic-warfare (EW) jammer or decoy and the other as a less complex glide bomb. The latter would have a lower cost than the baseline weapon but would be more lethal, thanks to a larger warhead.

- Spear 3 is one of the weapons that will allow the UK to declare full operational capability with the F-35

- Development of an EW version has attracted foreign interest

While both are being developed primarily using company money, the development of an EW capability has sparked interest from potential customers, some even providing initial funding, MBDA’s Spear 3 chief engineer Stephen Temple said at the Royal Aeronautical Society in London in April.

While both derivatives “leverage heavily from the main program,” he said, the current focus of the EW version’s development is around the propulsion and payload. The EW version will likely carry more fuel to give it a longer range and persistence. Temple sees the EW Spear 3 as providing a capability similar to Raytheon’s Miniature Air-Launched Decoy (MALD), in which the UK has shown interest.

The engineering team is currently working to understand the speed at which the EW Spear 3 will fly and the type of antennae it will need to deliver jamming waveforms.

Video produced by MBDA but not yet publicly released shows how an EW Spear 3 could be launched ahead of a salvo of standard weapons aimed at enemy air defenses.

Work on the glide version is running behind that of the EW derivative, but such a weapon would be significantly less expensive than the baseline weapon. Because there will be no need for a propulsion system and some of the high-end guidance capability, suggests Temple, this would make room for a larger warhead but result in a much shorter range—less than half that of the powered version, engineers think.

Taking a family approach and using the same airframe should help minimize the need for additional costly integration work.

Named after its UK Defense Ministry acronym, Selective Precision Effects at Range (Spear) Capability 3, the weapon is designed to give British F-35s, and possibly Eurofighter Typhoons, the ability to attack mobile, armored and semihardened targets from standoff ranges. Work is also underway to provide a maritime capability.

The 80-kg (176-lb.) missile is equipped with a small turbojet, extending ranges well beyond that of existing small-diameter glide bombs.

Building on MBDA’s development of the Brimstone, the Spear 3 will use a millimeter-wave radar seeker and semiactive laser terminal seeker and GPS/INS guidance and is capable of receiving updates via data link. Programmed prior to takeoff or launch, crews will be able to tune the warhead’s characteristics as well as define attack angles and azimuths.

MBDA is working with a four-year £411 million ($536 million) UK Defense Ministry design and development contract issued in 2016.

In March, it was announced that MBDA would support BAE Systems' and Lockheed Martin’s efforts to integrate the weapon onto the F-35. The Spear 3, along with the Meteor beyond-visual-range air-to-air missile, will be integrated as part of the F-35’s continuous capability development and delivery (C2D2) program.

MBDA carried out a test firing of a Spear 3 in 2016. This Airframe and Propulsion Demonstrator (APD) flew a series of preprogramed maneuvers before flying into the sea off western Wales, helping to derisk the company’s software modeling and analysis tools. Meanwhile, the programming of the weapon’s seeker has been conducted using an airborne testbed, carrying the seeker, navigation system and data link. The testbed allows the company to gather data for the radio-frequency element of the seeker so that it can more easily find targets against background clutter.

The next steps for the weapon’s development and flight trials are not being disclosed, but Temple says the company is building operationally representative equipment and beginning prequalification activities.

“We are really starting to learn about the product we are developing,” he says.

A key part of the work is developing two launchers for the weapon, a three-pack launcher for external pylons and the four-pack launcher for inside the weapons bay of the F-35 family of aircraft. The launchers pass much of the data from the aircraft to the weapons and eject the missile out of the weapons bay using a cold-gas pneumatic system.

Carried upside down on the pylon, once dropped, the weapon turns rightside up and opens its wings and fin stabilizers, while the turbojet is spooled up by windmilling air through intakes on either side of the missile’s body.

Designing the weapon to fit inside the constrained volume of the F-35 weapons bay has been the key design driver for the Spear 3.

The Spear 3 is the densest missile produced by the company. Although it is roughly the same size as the Brimstone in terms of diameter and length, it is twice the weight, with “more complexity than the Storm Shadow cruise missile,” says Temple.

The company has also had to consider the challenges posed by both internal and external carriage. Outside, the weapon is exposed to extreme cold, but inside the F-35 weapons bay, the temperature is considerably warmer, thanks to the proximity of the engine. This heat causes the Spear 3’s fuel to expand. The expansion characteristics of the fuel “took us by surprise,” says Temple, and could have had an impact on the amount of fuel carried. Too much expansion could rupture the system, while too little and the weapon may not meet its anticipated range.

“Packaging this amount of capability into a weapon that is relatively small drives a lot of design risks,” says Temple. “We are testing this system beyond the requirements because we don’t want to carry risk into the qualification program or F-35 integration program.”

The introduction of the Spear 3 onto British F-35s is one of the components that will enable the UK to declare full operational capability with the aircraft around 2023.

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