Thursday, March 15, 2012

Heat Vision: US Teen Series Fighters Getting IRST


B-2 Close View IRST
F/A-18 E/F Super Hornet Block IIs fighters are beginning to enter service with the US Navy and Australia, carrying significantly improved AN/APG-79 AESA radars andother electronic upgrades. Recent years have seen another spreading improvement within global fighter fleets, however: Infra-Red Search & Track (IRST) systems that provide long range thermal imaging against air and ground targets. Most of these deployments have been on Russian (MiG-29 family, SU-30 family) and European (EurofighterRafaleGripen NG) fighters, or special American exports (UAE’s F-16E/F Block 60 Desert Falcons, Korea & Singapore’s F-15K/SG Strike Eagles).
That absence puts American fighters behind an important curve. This IRST approach can defeat radar stealth in some instances, by focusing on engine exhaust, or on the friction of the aircraft as it powers through the atmosphere. As F-14 pilots will recall, long range electro-optics also offer positive identification, conferring the ability to use a plane’s aerial missiles at their full ranges. Best of all, IRST offers a passive way to locate and target enemy aircraft, without triggering the target’s radar warning receivers. When coupled with medium-range IR missiles like some Russian AA-10 variants, France’s MICA-IR, or even future versions of AMRAAM NCADE, an IRST system offers a fighter both an extra set of medium-range eyes, and a stealthy air-to-air combat weapon. Programs are underway to give some American “teen series” fighters this capability, albeit in a somewhat unusual way…

Tanks for the View: The IRST + Fuel Solution

F-18F with (Regular) Tanks
F/A-18F w. tanks
Retrofits into existing aircraft can be tricky, but in July 2007, Boeing’s RFI selection process and tapped Lockheed Martin’s Missiles and Fire Control division in Orlando, FL to supply up IRST systems for F/A-18 E/F Super Hornet Block II aircraft. That began as a Systems Development and Demonstration effort, but the program received Milestone B approval in July 2011, and the EMD contract followed in August 2011. The first production deliveries of up to F/A-18 E/F IRST systems were expected in 2012, with initial operational capability expected in 2013.
Lockheed Martin’s IRST is described as “the next generation of the F-14D AN/AAS-42 IRST that accumulated over 200,000 flight hours aboard U.S. aircraft carriers.” The question for Boeing was where to put it.
IRST Tank Cutaway
IRST tank
Instead of modifying the Super Hornet’s airframe’s structure or wiring, the partners will be taking an unusual route: modifying a 480 gallon centerline fuel tank to carry 330 gallons of fuel + the IRST system. The drawback to this approach is that a centerline tank with IRST needs to stay on the airplane in combat, compromising its aerodynamic performance and radar signature.
On the bright side, this approach will allow refits to existing Super Hornets, and indeed to all “teen series” fighters in the US arsenal, once software integration is performed to tie the IRST into each new plane type’s “multisource integration algorithms.” IRST tracking data must be correlated with other sensors like the fighter’s radar, radar warning receivers, etc., in order to make its surveillance and targeting simple enough to be useful to the pilot. MSIA integration ensures this.
Industrial partners in this effort are:
  • Boeing IDS (lead contractor)
  • Lockheed Martin Missiles and Fire Control (SpectIR IRST sensor)
  • General Electric (F/A-18 fuel tank with the sensor housing)
  • Meggitt Defense Systems Inc. (IRST unit’s cooling sub-assembly)

IRST Future: A SpectIR for all Teens?

F-15C SpectIR IRST
IRST pod on F-15C
A similar approach was suggested for the USAF’s F-15C/D fleet, but it would have been a full centerline pod, rather than a fuel tank with additional capabilities. The two firms already had a history of cooperation on this platform. Boeing has already installed Lockheed Martin’s Tiger Eyes system, which includes an IRST as part of its suite, on in Korean F-15K and RSAF F-15SG Strike Eagles.
The Pentagon’s FY 2012 budget proposes to end funding for that program, but Lockheed Martin and Boeing continued to develop “SpectIR” as an option that “will be transportable across a wide range of platforms.” The FY 2013 Presidential Budget for 2013 shows the USAF F-15C SpectIR program picking back up again in FY 2015, and the Air National Guard has its own options. Because IRST is an open ANG requirement for Homeland Defense, the US ANG can just use National Guard & Reserve Equipment Appropriation (NGREA) funds to buy a system, once it’s ready.
Lockheed Martin has privately funded a dedicated SpectIR IRST pod, and is using it to conduct tests and demonstrate this readiness. They see the market extending well beyond F-15 fleets. Integration work for the team will obviously be easier on Boeing and Lockheed Martin “teen series” fighters like the F-15, F-16 and F/A-18. Nevertheless, other platforms around the world would be eligible if manufacturers or customers wanted to fund integration.
As an interesting aside, there are reports that the USAF’s targeting pods chosen under the new ATP-SE contracts may provide a lesser form of air-to-air IRST capability, alongside the ground surveillance and attack functions.

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