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LGarde, also L'Garde or L·Garde, is an American
aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications. Aerospace engineering consists of aeronautics and astronau ...

aerospace
and defense technology company founded in 1971 in
Orange County, CA Orange County is located in the Los Angeles metropolitan area in Southern California, Southern California. As of the 2010 United States Census, 2010 census, the population was 3,010,232, making it the third-most populous county in California, t ...
and is the primary contractor for the Sunjammer spacecraft, the world largest
solar sail Solar sails (also called light sails or photon sails) are a method of spacecraft propulsion Spacecraft propulsion is any method used to accelerate spacecraft File:Space Shuttle Columbia launching.jpg, 275px, The US Space Shuttle flew ...
. The company was an early pioneer of thin-skinned, multi-task inflatable structures used in various military and space applications. At the height of the
Cold War The Cold War was a period of geopolitical Geopolitics (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country loc ...
, L·Garde developed and manufactured inflatable targets and decoy systems for U.S. military defense, and countermeasure systems for the
Strategic Defense Initiative The Strategic Defense Initiative (SDI), derisively nicknamed the "''Star Wars'' program", was a proposed missile defense Missile defense is a system, weapon, or technology involved in the detection, tracking, interception, and destructio ...
(Star Wars). After the Cold-War, the company used the technologies and manufacturing techniques it had developed to land a contract to design and build the
inflatable antenna experiment The Inflatable Antenna Experiment (IAE) was a NASA experiment that began on May 19, 1996, consisting of an inflatable antenna made of mylar which was launched from the Space Shuttle ''Space Shuttle Endeavour, Endeavour'' during the 1996 STS-77 mi ...

inflatable antenna experiment
and other thin-film inflatable space structures using its unique application of rigidizable tube technology. The company's unusual name is an acronym formed by the initials of the founding partners: Bill Larkin, Gayle Bilyeu, Alan Hirasuna, Rich Walstrom, Don Davis. The "E" comes from the Latin term "
et al Notes and references Notes References Sources * * * Further reading

* * {{Latin phrases Lists of Latin phrases, E ...
" (and others) as a tip to other partners and original employees of the company.


History

LGarde engineers took their experience with inflatable structures for military use to space applications around 1992 as a means of controlling the cost of deploying instrumentation into Earth orbit and beyond. They studied development work and lessons learned from projects for the
United States Department of Defense The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government A federation (also known as a federal state) is a political entity A polity is an identifiable political entity ...
and the
NASA The National Aeronautics and Space Administration (NASA; ) is an independent agency A regulatory agency or regulatory authority, is a Public benefit corporation Public-benefit corporation is a term that has different meanings in differen ...
going back to the 1960s. Observing the advantages and challenges of deploying a very large inflatable antenna and other structures in Earth orbit using this technology, LGarde engineers also observed changes in structural principles when such structures are used in a zero-gravity environment, and other technical issues arising for large precision structures including surface accuracy, analysis and electrical properties. LGarde's first inflatable space structure project was the Spartan 207 Project, also known as the
Inflatable Antenna Experiment The Inflatable Antenna Experiment (IAE) was a NASA experiment that began on May 19, 1996, consisting of an inflatable antenna made of mylar which was launched from the Space Shuttle ''Space Shuttle Endeavour, Endeavour'' during the 1996 STS-77 mi ...

Inflatable Antenna Experiment
, which was launched with
Space Shuttle Endeavour Space Shuttle ''Endeavour'' (Orbiter Vehicle Designation: OV-105) is a retired Space Shuttle orbiter, orbiter from NASA's Space Shuttle program and the fifth and final operational Space Shuttle, Shuttle built. It embarked on its first mission, S ...

Space Shuttle Endeavour
on mission STS-77, May 19. 1996. The goal of this mission was to inflate a 14-meter antenna on three 28-meter struts built by LGarde under contract with
JPL The Jet Propulsion Laboratory (JPL) is a federally funded research and development center Federally funded research and development centers (FFRDCs) are public-private partnerships which conduct research and development Research is " c ...
. The project was developed under NASA's In-STEP technology development program. Deployed using the shuttle's
Remote Manipulator System Canadarm or Canadarm1 (officially Shuttle Remote Manipulator System or SRMS) is a series of robotic arm A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm In human anatomy, the arm is ...
, the antenna was successfully inflated and the correct final shape was attained. According to the final mission report, the mission was successful and gained a great deal of information about inflating large structures in space. Among the points that the Spartan 207 project proved was the viability of inflatable space structures as a cost-saving concept. The inflatable antenna weighed only about 132 pounds (60 kilograms) and an operational version of the antenna may be developed for less than $10 million - a substantial savings over current mechanically deployable hard structures that may cost as much as $200 million to develop and deliver to space. LGarde engineers expanded their development of inflatable rigidizable structures with low mass structures strong enough to support orbital large solar arrays as well as much smaller
nanosat A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under . While all such satellites can be referred to as "small", different classifications are used to categorize them based on mass. Satellites ca ...
s. Among the many detail design parameters they considered were tube design (for rigidizable material), alternative beam types and designs (e.g., trusses), material thickness, laminates, and the best way to resolve Euler
buckling In structural engineering Structural engineering is a sub-discipline of in which s are trained to design the 'bones and muscles' that create the form and shape of man-made structures. also must understand and calculate the , strength, and ...

buckling
. A project, conducted with JPL under NASA's Gossamer Spacecraft program in 1999, sought to build an inflatable reflector to concentrate solar energy for space electrical power generation, while acting as a large aperture high gain antenna. Among the goals of the Gossamer Spacecraft program was to reduce the mass and stowage volumes of a power antenna while maintaining comparable yield from electrical power generation. Additional development came in 2005, when LGarde began utilizing material rigidization methods that provide a long lasting reflector shape without requiring continuous inflation. Engineers settled on an aluminum/plastic laminate as the rigidization method of choice over cold rigidization of a
Kevlar Kevlar (para-aramid) is a heat-resistant and strong synthetic fiber Synthetic fiber or synthetic fibre (in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, ...
thermoplasticelastomer composite as a means of accomplishing two goals: 1) diminish stowage space and thereby expanding the potential aperture size of the mirror reflectors and 2) eliminate the need for “make-up” gas needed for purely inflatable reflectors to remain inflated in space. LGarde engineers later advanced the readiness level of the inflatable planar support structure for the gossamer antenna system with additional design, analysis, testing, and fabrication of an inflation-deployed rigidized support structure for the waveguide array. Going into 2002, LGarde was developing polyurethane resins for a 3-ply composite laminate that could be used in the fabrication of rigidizable structures suitable for use in space. In a paper submitted to the American Institute of Aeronautics and Astronautics (
AIAA The American Institute of Aeronautics and Astronautics (AIAA) is a professional society for the field of aerospace engineering Aerospace engineering is the primary field of concerned with the development of and . It has two major and overla ...
), engineers found that such composites can be used to fabricate ultra-lightweight deployable rigidizable structures for space applications and that polyurethane was chosen because it could become rigid when exposed to the low temperatures of space. The paper goes on to observe that under NASA's SSP program (
Space Solar Power Space-based solar power (SBSP) is the concept of collecting solar power in outer space and distributing it to Earth. Potential advantages of collecting solar energy in space include a higher collection rate and a longer collection period due to ...

Space Solar Power
Truss), a 24-foot long inflatable-rigidizable truss using polyurethane composites withstood a compression load of 556 pounds, 10% above its designed compression strength while reducing mass of comparable mechanical structures by a factor of 4. It had been long theorized that
solar sails Solar sails (also called light sails or photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. A number of spaceflight missions to test solar propulsion and navigation have been prop ...
could reflect photons streaming from the sun and convert some of the energy into thrust. The resulting thrust, though small, is continuous and acts for the life of the mission without the need for propellant. In 2003, LGarde, together with partners JPL,
Ball Aerospace Ball Aerospace & Technologies Corp. (commonly Ball Aerospace) is an American manufacturer of spacecraft, components, and instruments for national defense, civil space and commercial space applications. The company is a wholly owned subsidiary of ...
, and
Langley Research Center The Langley Research Center (LaRC or NASA Langley), located in Hampton Hampton may refer to: Places Australia *Hampton (biogeographic region), an IBRA biogeographic region in Western Australia *Hampton, New South Wales *Hampton, Queensland *H ...

Langley Research Center
, under the direction of NASA, developed a solar sail configuration that utilized inflatable rigidized boom components to achieve 10,000 m2 sailcraft with a real density of 14.1 g/m2 and potential acceleration of 0.58 mm/s2. The entire configuration released by the upper stage has a mass of 232.9 kg and required just 1.7 m3 of volume in the booster. Additional advancement of the solar sail project came as LGarde engineers improved “sailcraft” coordinate systems and proposed a standard to report propulsion performance. LGarde was selected by NASA to build construct the Sunjammer spacecraft, currently the world largest solar sail. Slated for launch in January 2015, Sunjammer is constructed of Kapton and is 38 metres (124 ft) square with a total surface area of over 1,200 square metres (13,000 sq ft). The ultrathin 'sail' material is only 5 μm thick with a low weight of about 32 kilograms (70 lb). Once in space, the large surface area of the solar sail will allow it to achieve a thrust of about 0.01  N. To control its orientation, via this its speed and direction, Sunjammer will use gimballed vanes (each of which is itself a small solar sail) located at the tips of each of its 4 booms completely eliminating the need for standard propellant. On October 17, 2014, NASA cancelled the Sunjammer project after investing four years and more than $21 million on the project.


References

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