CONGRESS OF THE UNITED STATESCONGRESSIONAL BUDGET OFFICE

CBORecent

Development Efforts for

Military Airships

NOVEMBER 2011

Pub. No. 4239

ffice

CBO

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The Congress of the United States O Congressional Budget O

Recent Development Efforts fMilitary Airships

November 2011

CBO

Notes and Definitions

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The cover shows a U.S. Navy MZ-3A manned airship landing at Lake Front Airport, New Orleans, Louiprovide support for the Deepwater Unified Command and the Gulf of Mexico oil spill. Photo by Mass CoSpecialist 2nd Class Andrew Geraci.

Aerostat: A tethered, unmanned airship.

Airlift: The transportation of people, equipment, or other cargo by air.

Airship: An aircraft that obtains buoyant lift from a contained volume of helium or other gas that is less dsurrounding air. Also referred to as a lighter-than-air vehicle.

Conventional Aircraft: An aircraft that does not rely on buoyant lift to achieve flight. In this document tincludes fixed-wing aircraft, tilt-rotor aircraft, and helicopters.

Conventional Airship: An airship that uses only buoyant lift to achieve flight.

Envelope: The external structure of an airship within which the helium or other buoyant gas is located. Tcategories of envelopes: rigid, semirigid and nonrigid. Rigid envelopes use an internal frame to keep theirSemirigid envelopes use a keel along the bottom of the envelope to distribute weight. Nonrigid envelopframe and use only gas and envelope design to keep their shape.

Hybrid Airship: An airship that uses a combination of buoyant lift from helium, aerodynamic lift from thenvelope, and variable-direction thrust (more commonly called vectored thrust) to stay aloft.

Intelligence, Surveillance, and Reconnaissance (ISR): Reconnaissance operations observe an area to collinformation. Surveillance is the systematic observation of a particular area. Intelligence is the product of and reconnaissance once the information from those operations has been analyzed and evaluated.

Orbit: In this document, orbit refers to the region in the sky in which an aircraft operates while it is obseactivities below. In military parlance, an aircraft orbit is often called a combat air patrol, or CAP.

Payload-duration: Payload-duration is the weight (payload) that could be carried to a location multipliedamount of time it could remain there (duration).

Preface

CBO

Airships raft the Departmen e; and airlift. The uniqu to aircraft currently i

At the requ ce (CBO) examined to provide objective, i

Alec Johns David Arthur, un d Kempinski. Charles W Hopkins University r the final product, w

Jeanine Re udy for publication da Schimmel coordinate

November

also known as lighter-than-air vehicleshave been proposed as alternatives to some of the airct of Defense uses today for two types of missions: intelligence, surveillance, and reconnaissanc

e characteristics of airships offer some advantages and disadvantages for those missions relative n the fleet.

est of the Chairman of the Senate Armed Services Committee, the Congressional Budget Offithe Department of Defenses plans and proposals for airships. In keeping with CBOs mandate mpartial analysis, this study makes no recommendations.

on, formerly of CBOs National Security Division, prepared the document, with assistance fromder the general supervision of David Mosher. The line drawings of airships were done by Bernarhalen of CBO provided helpful comments on the report, as did Mark T. Lewellyn of the Johns Applied Physics Laboratory. The assistance of an external reviewer implies no responsibility fohich rests solely with CBO.

es and John Skeen edited the document. Maureen Costantino and Jeanine Rees prepared the st, and Maureen Costantino designed the cover. Monte Ruffin printed the initial copies, and Lin

d the print distribution. This publication is available on CBOs Web site (www.cbo.gov).

Douglas W. Elmendorf Director

2011

http://www.cbo.govjeaninerDoug

CBO

Exhibit Page

List of Exhibits

1. Illustrations of Airships 6

2. Wind Speed and Location, Altitude, and Time of Year 7

3. General Characteristics of Airships Under Consideration by DoD 8

Low-Altitude Intelligence, Surveillance, and Reconnaissance

4. Low-Altitude Airships for Intelligence, Surveillance, and Reconnaissance 10

5. Payload, Endurance, and Speed of Low-Altitude Airships and Fixed-Wing Aircraft 11

6. Payload-Duration of Low-Altitude Airships and Fixed-Wing Aircraft 12

High-Altitude Intelligence, Surveillance and Reconnaissance

7. High-Altitude Airships for Intelligence, Surveillance, and Reconnaissance 14

8. Payload, Endurance, and Speed of High-Altitude Airships and Fixed-Wing Aircraft 15

9. Payload-Duration of High-Altitude Airships and Fixed-Wing Aircraft 16

Airlift

10. Proposed Airships for Airlift 18

11. Approximate Performance Characteristics of Proposed Airships for Airlift 19

12. Performance for an Illustrative Deployment to the Middle East 20

13. ation of the Number of Aircraft Needed to Provide 1,000 Tons per Day Throughput Within a Theater of Operations 21

Airlift

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sulting craft could serve effectively in the ISR d airlift roles;

irships performance characteristics would ovide some advantages and suffer from some sadvantages relative to those of the conven-onal aircraft currently used for ISR and airlift issions; and

irships would present new operational chal-nges such as greater sensitivity to weather nditions and the need to provide unique pes of maintenance and support.

use the development of the technology needed odern military airships is at an early stage, in cases cost estimates would be highly specula-therefore, CBO does not examine the costs of ips here. Although CBO does compare the ilities of airships to those of other aircraft,

sing cost-effectiveness would require analyzing as various technologies mature.

kgroundips were among the first aircraft to see useful ary service. German Navy airships were flying time patrol missions as early as 1914, and the zeppelin bombing raids on Great Britain were d in early 1915. Beginning in 1917, the U.S.

nal Bcraft S

During the pastand Iraq, the Uon the continuoverhead of botto support grouremain aloft in have been primmation about aattack ground tnent among theDefenses (DoDReapers, and Gmanned convenand long-range

The demand foloitering missstantially enlargand the Army, or plan to fieldgence, surveillalight-attack capaircraft are partbecause they cabeyond the phyand because theoperations in p

1. See CongressioUnmanned Air

for unmanned airships can be achieved, the stage

udget Office, Policy Options for ystems (June 2011).

eets of unmanned Predators, Hawks; however, satellites and al aircraft, including fighters bers, have also contributed.

se so-called persistent or has led the Air Force to sub- fleet of unmanned aircraft, , and Marine Corps to field lar aircraft to provide intelli-and reconnaissance (ISR) and ties of their own.1 Unmanned rly attractive for such missions designed to provide durations endurance of human air crews not put humans at risk during ially hostile airspace.

carrying ISR sensors.

The technology needed to field airships for ISR could also be applied to airships meant for airliftthat is, for the transportation of people, equip-ment, or other cargo. Whether airships designed to carry cargo would be manned or unmanned would depend on the specific missions they per-formed. Although the military services investment in developing airships for airlift has been limited, several private companies are exploring potential designs or are in the process of building prototypes.

In this document, the Congressional Budget Office (CBO) examines the potential capabilities of air-ships for ISR and airlift missions. In brief, CBO finds that:

B If the speed, payload, and endurance proposed

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Recent Development Efforts forMilitary Airships

ades operations in Afghanistan ilitary has come to rely heavily r nearly continuous presence anned and unmanned aircraft roops. Unmanned aircraft that cular locations (or orbits) used to provide timely infor-ies on the ground and to s on short notice. Most promi-rcraft are the Department of

In light of the demand for aircraft capable of remaining aloft for long periods of time, considerable interest in airships as alternatives to conventional aircraft exists. Although unmanned airships are unproven, they have the potential to remain in the air for long periodsproviding mission durations that are many times longer than would be practical for conventional aircraft. Con-sequently, the military services are exploring a variety of designs for unmanned airships capable of

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INT RECENT DEVELOPMENT EFFORTS FOR MILITARY AIRSHIPS 2

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