Main Image Credit E-7A Wedgetail photographed by Alex Layzell (Licence: Wikimedia Commons)
The two ISTAR types are expensive but remain some of the most operationally relevant and flexible capabilities in the equipment plan, with a vital role to play in support of the RAF and the wider joint force in both high-intensity warfighting and ongoing low-intensity mission sets.
One of the most significant questions facing service chiefs and procurement planners is the extent to which the armed forces should be optimised for the very different requirements of low-intensity expeditionary and stabilisation operations at reach, as opposed to warfighting capabilities against peer- or near-peer opponents. The Integrated Review will hopefully add significant clarity to this question in terms of government policy. With limited but increasing numbers of F-35Bs to provide penetrating strike and ISTAR capabilities, the new Protector RPAS (remotely piloted air system) replacing the MQ-9 Reaper for persistent operations in permissive airspace, and a large core fleet of the flexible multirole Typhoon, the RAF’s combat air portfolio is broadly suitable for most scenarios. However, the ISTAR fleet might see significant changes to the future force structure if there is a notable swing in policy emphasis towards high-end warfighting credibility.
The need to generate effective combat power through limited numbers of boots on the ground during contingency operations implies a heavy reliance on ISTAR assets. Airframe survivability (though important) is less relevant for such tasks than specialist sensor capabilities and comprehensive onboard communications suites. This is because air superiority, or at least freedom from direct kinetic attack by radar-guided surface-to-air missiles and fast jets, is typically a precondition for sustained contingency operations. The RAF ISTAR force includes several types designed to operate in such conditions, including the turboprop-powered Shadow R1 with an electronic intelligence (ELINT) suite and electro-optical surveillance capabilities which make it particularly suitable for providing support to special operations forces, and the Sentinel R1 with its powerful ground moving target indicator (GMTI) radar which enables coalition forces to track and analyse patterns of movement over a wide operational area.
The requirements for ISTAR during high-intensity warfighting in the 2020s and beyond are likely to be very different, however. The continued development and proliferation of advanced air defence systems by a range of threat actors will force traditional ISTAR assets to stand off hundreds of kilometres from the frontline during the critical and potentially decisive stages of a future state-on-state confrontation. This situation will worsen through the 2020s and into the 2030s as Russian and Chinese fast jets and unmanned combat aerial vehicles (UCAVs) with low-observable properties and long-range missiles with multi-mode active seekers begin to be manufactured in quantity and potentially proliferate to near-peer states. This dramatically reduces the value of traditional ISTAR platforms which rely on direct line-of-sight to ground-based targets in order to be effective. Orbital surveillance can help, but satellites follow trackable orbits with predictable coverage periods over a given area, and can be degraded by kinetic and electronic attack in addition to dense cloud cover.
As such, the air forces of states which require warfighting credibility against modern state adversaries will have to replace the majority of existing ISTAR types with penetrating ISTAR solutions. Options are likely to include a range of low-observable UAVs with low-probability of intercept/detection (LPI/PLD) datalinks, as well as smaller expendable vehicles in the size and weight class of cruise missiles with sensor payloads. These solutions will be expensive and only able to give temporary windows of ISTAR coverage within defended or contested airspace. For the UK, however, there are two classes of ISTAR asset which are likely to remain very useful well into the 2030s for both contingency or high-intensity operations. These are maritime patrol aircraft (MPA) and air battle management and surveillance (ABM&S) assets, also known as AWACS.
MPAs are essential because the UK is economically and militarily dependent on sea lines of communication, with an exclusively submarine-based nuclear deterrent force, and a relatively small surface fleet centred around two new aircraft carriers. Russia continues to build extremely quiet diesel electric and nuclear attack submarines, and to sell the former widely. ‘De-lousing’ the Vanguard-class ballistic missile submarines of shadowing Russian boats remains a key part of each nuclear deterrent patrol, and will continue to be required for the eventual Dreadnought successor class. Furthermore, the proliferation of quiet air-independent propulsion submarines already means that the Queen Elizabeth-class carriers will need anti-submarine protection in many potential trouble spots around the world, not least in the Indo-Pacific.
Closer to home, contributing strong forces to the ASW effort to contain the Russian Navy in its bastions east of the Greenland–Iceland–UK gap remains a key UK responsibility within NATO. Luckily, in the shape of the P-8A Poseidon, the RAF has acquired the world’s most capable MPA. Issues remain in terms of compatibility between its US Navy-standard communications and mission systems, sonobuoys and weapons and those used by the Royal Navy, but the biggest obstacle to long-term effectiveness in both high-intensity and enduring peacetime commitments is likely to be the reduced fleet size of nine compared to the 35 preceding Nimrod MR2s. In a conflict, there would be less risk to MPAs than most other ISTAR missions due to the fact that the core ASW task generally involves operating a long way from concentrations of Russian ground-based or aerial threats.
For the ABM&S mission, the RAF is currently in the process of replacing its troubled E-3D Sentry fleet with the E-7 Wedgetail. The E-7 has a multi-role electronically scanned array radar with significantly superior performance against air, ground and maritime targets compared to the E-3D’s AN/APY-1/2, as well as the potential for significant capability growth as a broadband communications relay and electronic warfare asset. The Wedgetail had a rocky introduction to service with the Royal Australian Air Force (RAAF), but has subsequently performed very well over Syria and Iraq in support of operations against the Islamic State. According to aircrew with first-hand experience of Red Flag exercises in the US, E-7 offers fast jet crews markedly superior quality track information against high-end threats than the US Air Force’s own modernised E-3G Sentry.
Although the initial UK order was for five E-7s, it has been reported that a reduction to three or four is being considered by the Ministry of Defence as a cost-saving measure. In addition, the force is being relocated from the main ISTAR base at RAF Waddington to RAF Lossiemouth for maintenance and support commonality with the similarly 737-derived P-8 fleet based there. In addition to cost-saving motives, there are thought to be concerns in some quarters about the service life prospects for the E-7 given the proliferation of threats to traditional ISTAR enablers already discussed.
The RAAF has recently announced a $582.5-million upgrade programme to ensure its E-7 fleet remains effective in service until at least 2035. The US Air Force itself is looking at a replacement for the E-3G by 2035 as part of the Alliance Future Surveillance and Control programme. To this end, it is examining various options for distributed airborne and orbital sensor networks to replace the surveillance and early warning aspects of the AWACS (ABM&S in UK terms) mission. Meanwhile, the theory is that a permutation of the Advanced Battle Management System (ABMS) might be able to replace the E-3G’s battle management and C2 node roles via a networked approach relying on seamlessly linked and coordinated sensor, shooter and relay systems on distributed platforms throughout the battlespace. If this approach sounds complex and confusing, it is. The Pentagon has not yet publicly explained how the later stages of ABMS will work in practice, especially in a heavy electronic warfare environment, nor how it will fit within the broader Joint All-Domain Command and Control (JADC2) programme. Furthermore, the US Air Force has left open the option of purchasing another airliner- or business jet-derived platform to replace at least some of what the E-3G does, in the absence of a clear and coherent path to performing all of the E-3G’s current missions with a distributed approach by 2035. For the RAF, this means that a common transatlantic distributed solution to the ABM&S mission set is unlikely to be available to purchase and bring into service before around 2040. Furthermore, any such solution is likely to rely heavily on purchases of US-made equipment across the force due to its nature as a distributed network architecture reliant on sensitive LPI/LPD datalink and encryption technology on large numbers of joint assets. It will also be a solution optimised for warfighting against China in the Indo-Pacific, and may be less than optimal for the UK’s geography, infrastructure, budget and threat environment.
None of this is meant to suggest that the UK should not pursue distributed surveillance, airborne early warning and battle management capabilities. However, increasingly ubiquitous unmanned systems, the deployment of swarming munitions, and the acquisition of low-observable types by competitors will all increase the need for modern wide-area early warning and battle management capacity in both low- and high-intensity scenarios during the 2020s and 2030s. None of the distributed network-centric approaches to replicating this role are clearly defined yet, nor is the rest of the RAF force structure currently configured to adopt such an approach.
While it is by no means a perfect ABM&S solution, the E-7 is available quickly, with a highly capable sensor, communications suite and mission system. RAF E-7 acquisition was approved in controversial circumstances using funds that had previously been allocated to E-3D life extension. Given continuing financial pressure on the equipment plan, alternative ABM&S choices are unlikely to be successfully procured to replace E-7 if the programme fails; meaning that at this point the choice is between a viable E-7 fleet or an ABM&S capability gap. The move to RAF Lossiemouth will save money while likely mandating a reduction in fleet size to four due to current maintenance and hanger capacity; but even four would be greatly preferable to three. With only three aircraft, the ability to sustainably guarantee even one aircraft on station where and when needed is highly questionable. Although the US Air Force and RAAF are looking at options for replacing the traditional AWACS around 2035, a great deal will happen in the world between now and then, and in many scenarios the RAF is likely to need both the P-8 and E-7 in sustainable numbers. If by 2040 they are already being replaced by networks, artificial intelligence processes and distributed sensor constellations that are robust enough to perform reliably in the face of enemy efforts to deny them, then they will still have given 20 years’ valuable service, and the Ministry of Defence can congratulate itself on having shortened procurement and modernisation cycles in line with the requirements of a rapidly changing world.
Justin Bronk is Research Fellow for Airpower and Technology at RUSI.
Research Fellow, Airpower & Technology