“…According to the North American Aerospace Defense Command (NORAD), 11 high-altitude airships would provide overlapping radar coverage of all maritime and southern border approaches to the continental U.S., and may be a significant asset in homeland defense efforts. The Stratospheric Platform System (SPS) dirigible operates just barely within the outer limits of the earth’s atmosphere and is emerging as part of the military’s 21st century transformational mindset….”
High Altitude Airship (HAA)
As posted at Global Security
Lockheed Martin Naval Electronics & Surveillance Systems-Akron, a unit of Lockheed Martin, with its partners —Stratcom International and others—have developed an unmanned lighter-than-air vehicle that would operate above the jet stream and above severe weather in a geostationary position to serve as a telecommunications relay, a weather observer, or a peacekeeper from its over-the-horizon perch.
According to the North American Aerospace Defense Command (NORAD), 11 high-altitude airships would provide overlapping radar coverage of all maritime and southern border approaches to the continental U.S., and may be a significant asset in homeland defense efforts. The Stratospheric Platform System (SPS) dirigible operates just barely within the outer limits of the earth’s atmosphere and is emerging as part of the military’s 21st century transformational mindset.
SPS is an unmanned, powered airship that can maintain a relatively geostationary position at 70,000 feet. Lift is provided by helium that is contained in its envelope. Differential thrust, electric-powered props control the pitch and roll and keep it in position. With the advent of thin-film photovoltaic solar cells (capable of producing voltage when exposed to radiant light), commercially available fuel cells, and lightweight/high-strength fabrics, a high-altitude airship could stay on station weeks or even months at a time by generating its own power and keeping helium loss to a minimal amount.
On station, the onboard sensors’ surveillance coverage extends over the horizon and monitors a diametric surface area of 775 miles. At nearly 500 feet long and 150 feet in diameter at its widest girth, the airship’s volume exceeds 5 million cubic feet.
This updated concept of a tried and proven technology takes lighter-than-air vehicles beyond the surface exclamations of: “Look, there’s the Goodyear blimp.” As a matter of fact, the Akron, Ohio, Lockheed Martin business unit supports the tire company’s blimp fleet as the FAA certificated manufacturer and maintenance provider.
Now, though, things have changed. Lighter-than-air vehicles operating at altitudes of 21 kilometers (70,000 feet) are nearing a reality thanks in large measure to the technical savvy of Lockheed Martin NE&SS-Akron and the convictions of Stratcom President Lt. Gen. James Abrahamson, USAF (retired), and other members of its stratospheric airship industrial team.
All vital technologies have been evaluated individually during the recently concluded concept feasibility phase, which began in October 1998, and are ready for integration into a demonstration vehicle. The evolution of the design over this period has illustrated a host of design, operational, and manufacturing issues that are significantly different than the issues resulting from development of fixed-wing aircraft or even a conventional LTA vehicle.
Maintaining geostationary position over long periods requires a detailed understanding of the environment at 21 km. This altitude was chosen because of its minimal wind conditions during a significant part of the year. Wind profiles tend to reduce to a minimum a short distance above the jet stream. However, long-term, reliable and continuous data on winds and turbulence at this altitude are not available for the entire earth’s surface. Therefore, variable winds and turbulence, even though the air density is only five percent of that at the surface, could still place severe demands on propulsion, control and navigation systems.
Buoyant vehicles require periodic checks on the helium purity. This is done frequently with blimps. For the vehicle operating at 21 km, the design has taken into account leakage of helium as well as migration of air and water vapor into the helium enclosure. Degradation of buoyant lift will be minimized by envelope design.
Since it is not practical to carry fuel aloft in a long-endurance buoyant vehicle, all power must be generated on station. This includes payload and propulsive power. A combination of photovoltaic (PV) and fuel cell systems likely will be used to provide the multiple kilowatts of power necessary for these functions. The PV and regenerative fuel cell technologies required by the vehicle are being developed based on work at NASA-Glenn in Cleveland.
Lockheed Martin’s unique experience with certificating the GZ-22 airship with the FAA allows it to understand and address the concerns of flight through controlled airspace, especially with an unmanned airship. Safety of flight issues, operation of an unmanned vehicle, and operation over populated areas are all concerns that we have addressed during the design evolution. While most of the issues noted are not unique to special aircraft designers, it is the combination of these factors along with the long endurance that makes the design problem a difficult one.
The vehicle might be built in the company’s Akron Airdock, which is 1,175 feet long, 325 feet wide and 211 feet high. Its height is equal to a 22-story building.
Lockheed Martin NE&SS-Akron received its first production contract for a lighter-than-air vehicle, the rigid USS Akron airship, in 1928 from the U.S. Navy. Since that time, the Lockheed Martin unit has built more than 300 airships and several thousand aerostats.
The North American Aerospace Defense (NORAD) has asked for funding to build a prototype high-altitude airship, with the idea of stationing 10 ships to cover all the continental borders of the United States.
The Technical Center of the U.S. Army Space and Missile Defense Command (USASMDC) seeks sources capable of and interested in developing a prototype unmanned, un-tethered lighter than air (LTA) vehicle, or airship, that can operate autonomously in the stratosphere for sustained long-endurance operations. The principle objectives of the HAA Program are to develop a prototype airship that can lift a payload of at least two metric short tons (1814 kilograms, or 4000 pounds) to a pressure altitude of approximately 21.33 kilometers (70,000 feet), maintain geostationary orbit at that altitude above a fixed location on the earth for at least six months, be controllable from a remote ground station, provide a payload environment suitable for electronic equipment with a maximum unobstructed viewing line-of-sight around the airship, and generate sufficient power to operate all airship subsystems and electronic payloads (with appropriate design margins and duty cycles) for continuous operations. Instrumentation should be included to characterize the flight environment, airship stability and control, internal airship thermal and atmospheric environment (humidity and gaseous composition), power generation and management, and the payload environment (thermal, air composition, electro-magnetic, and vibration). Provisions should be made to transmit the instrumentation data to the ground for airship system status and performance evaluation. To the maximum extent possible, the prototype design should utilize components, structures, and subsystems that are scaleable to an operational airship with the same operational requirements, but having a payload capability five to six times greater than that of the prototype.
USASMDC believes that the airship resulting from this effort will have significant commercial applications -in telecommunications, for example. Given this potential, USASMDC plans to enter into a cost-sharing arrangement for the performance of this effort as an “Other Transaction for Prototype” under the authority of 10 U.S.C. 2371 and Section 845 of Public Law 103-160, as amended. (SMDC, however, reserves the right to elect to enter into a “traditional” contractual arrangement under the Federal Acquisition Regulation.) An Other Transaction arrangement offers maximum flexibility and encourages use of commercial business practices, including negotiation of intellectual property rights. Non-traditional defense contractors are encouraged to participate. The planned period of performance for this effort is 24 months, including design, fabrication and flight test.
On 29 September 2003 Lockheed Martin Naval Electronics & Surveillance Systems, Akron, Ohio, was awarded agreement HQ0006-04-9-0001 for design and risk reduction phase 2 of the High Altitude Airship advanced concept technology demonstration. The objective of this Phase 2 effort is to continue design (through critical design review) and technical risk reduction efforts for a high-altitude airship system prototype that will demonstrate military utility by operating in the stratosphere as a long-endurance, quasi-geostationary platform with a contractor-supplied, government-approved payload or a government-supplied payload. The estimated total value for Phase 2 is $40,000,000 with a period of performance from October 2003 to June 2004. There is an option for a prototype, development, build and demonstration Phase 3 for an estimated total value of $50,000,000 with a period of performance from June 2004 to July 2006 and a follow-on option for an Extended User Evaluation Period Phase 4 for an estimated total value of $9,000,000 with a period of performance from August 2006 to July 2008. The Missile Defense Agency is the contracting activity (HQ0006-04-9-0001).