Return of the Navy Blimps?Mar 02, 2007 07:30 UTC by Defense Industry Daily staff
In the aftermath of World War 2, blimps and airships found themselves gradually phased out of the US military. That didn’t really begin to change until the 21st century (see April 2005, “USN, DARPA See Blimps & HULAs Rising“). The heavy-lift WALRUS project may have been canceled without explanation; but aerostat programs like JLENS cruise missile defense and its smaller RAID local surveillance derivative, and airships like the HAA/ISIS program, remain. The US Navy is also experimenting with aerostats for communications relay, surveillance, and radar overwatch functions – and this has become a formal program.
What’s driving this interest? Four things. One is persistence, in an era where constant surveillance + rapid precision strike creates a formidable military asset. A second is cost, especially in an era of rising fuel prices. A recent US NAVSEA release offers figures that starkly illustrate the gap in surveillance cost per hour between an aerostat and planes or UAVs:
- Land-based 71-meter aerostat: about $610/ hour
- MQ-1 Predator MALE (Medium Altitude, Long Endurance) UAV: about $5,000/ hour
- E-2C Hawkeye AWACS (Airborne Warning And Control System) aircraft: about $18,000/ hour
- RQ-4 Global Hawk HALE (High Altitude, Long Endurance) UAV: about $26,500/ hour
The third driver is ballooning bandwidth demands due to increased employment of UAVs and other systems with streaming video. This is a long-term trend that will demand very expensive satellites with long design/launch times – or cheaper patchwork solutions that can remain at altitude for long periods.
The fourth driver is the proliferation and increased lethality of cruise missiles. On land, the concern is the combination of cruise missiles and weapons of mass destruction. At sea, the concern is the increasing lethality of anti-ship cruise missiles, including supersonic varieties that place a premium on early detection in order to give defensive systems enough time.
Aerostats are not blimps, and need no pilot. These helium filled, multi-chambered balloons are winched up or down via a combined tether/power line; and can be deployed from trucks, land platforms, or a ship at sea. They can stay at-altitude and on station for weeks at a time, which makes them well-suited for providing over-the-horizon airborne radar, surveillance coverage, and/or communication relays for areas like ports, key sea lanes & straits, coastal areas, main transportation highways, national borders, or demilitarized zones.
Their multiple helium pockets and low differential pressure between the helium and the atmosphere also make them hard to kill, even if shot full of holes. The helium just escapes slowly, and the aerostat will still remain aloft for hours or even days. During one incident in Iraq, a small RAID aerostat came loose from its tether and the US Air Force barely managed to shoot it down before it drifted over the Iranian border.
Aerostats will not replace naval surveillance aircraft. Their tethered nature creates substantial drag when moving at speed, and keeping them aloft at altitude becomes difficult in those circumstances. High winds and thunderstorms can ground them, in situations where aircraft could still fly. They also have rather large radar reflections, which can compromise task force stealth. Their offsetting advantages, however, may make them a critical naval supplement to be deployed over ports or staging areas; or from ships in or near “hot” zones like beachheads, or on picket in and near dangerous areas like the Persian Gulf, Straits of Malacca, Somali coast, et. al.
Accordingly, the USA’s NAVSEA(NAVal SEA Systems Command) and NAVAIR (NAVal AIR Systems Command) signed a memorandum of understanding on Oct. 28, 2006 to develop a sea-based 38-meter aerostat prototype with a weather hardened design that can carry up to 500 pounds of surveillance equipment. That’s NAVAIR’s area of expertise, and they will use a 32 meter aerostat they’ve been experimenting with as a base platform. The Navy also wants to develop this aerostat to accommodate a modular, interchangeable payload system that can offer radar, optronics, communications, or set combinations for maximum flexibility. That’s NAVSEA’s area of expertise.
The ultimate goal of the program is to develop a sea-based 71-meter, weather-hardened aerostat sensor platform, with larger interchangeable payload modules, capable of operating at an altitude of up to 15,000 feet. This would be conceptually similar to the land-based JLENS aerostats, which will provide cruise missile defense on land.
- Wall St. Journal (Aug 27/03) – More Than Just Hot Air. Describes the efforts underway in the US Navy’s efforts, with Steve Huett acting as point man for the concepts. Like Fox, they report that the USN is working with Science & Technology International, a Hawaiian based company whose sensors have been used to track whales.
- Fox News (Aug 7/03) – US Navy May Use Blimps as Anti-Terror Tool
- New York Times (March 22/87) – The Battle To Build The Navy’s Blimp. At the time, the Navy needed a radar that could pick up small anti-ship missiles at ranges greater than an AEGIS radar’s; AWACS planes weren’t yet up to the job. Despite all the hoopla, the program did not survive.