View source for Linear Aerospike SR-71 Experiment

{{short description|Linear Aerospike SR-71 Experiment 1997/8 NASA for X-33}}
[[Image:SR-71 LASRE.jpg|thumb|Closeup of rear of LASRE pod]]
[[Image:SR-71 LASRE cold test.jpg|thumb|LASRE cold test dumping water after first in-flight cold flow test - 4 March 1998]]
[[File:Linear Aerospike SR-71 Experiment (LASRE) ground cold flow test. NASA Photo.jpg|thumb|Linear Aerospike SR-71 Experiment (LASRE) ground cold flow test]]
'''LASRE''' was [[NASA]]'s '''Linear Aerospike SR-71 Experiment''' which took place at the [[Dryden Flight Research Center]] at [[Edwards Air Force Base]], California, until November 1998. The experiment sought to provide flight data to help [[Lockheed Martin]] validate and tune the computational predictive tools used to determine the [[Aerodynamics|aerodynamic]] performance of the [[Lockheed Martin X-33]] [[lifting body]] and linear [[aerospike engine]] combination and to lay groundwork for a future [[reusable launch vehicle]].<ref name="fact sheet">{{cite web|url=http://www.nasa.gov/centers/dryden/news/FactSheets/FS-043-DFRC.html|title=NASA Dryden Fact Sheet - LASRE Project|date=7 May 2008|author=Marty Curry|accessdate=14 July 2012|publisher=NASA}}</ref>

LASRE was a small, half-span model of the X-33's lifting body with eight thrust cells of an [[aerospike engine]], rotated 90 degrees and mounted on the back of a [[Lockheed SR-71 Blackbird]] aircraft, to operate like a kind of "flying [[wind tunnel]]." The experiment focused on determining how a reusable launch vehicle's engine plume would affect the aerodynamics of its lifting body shape at specific altitudes and speeds reaching about 750 miles/hour (335 meter/second or 1207&nbsp;km/h). Design refinements looked to minimize the interaction of the aerodynamic flow with the engine plume, which could create drag.<ref name="NASA"/>

The aircraft completed seven research flights. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus on the back of the aircraft. The first of those occurred 31 October 1997. The SR-71 took off at 8:31&nbsp;a.m. ([[Pacific Standard Time]]-PST).<ref name="NASA"/> The aircraft flew for 1:50 hour, reaching Mach 1.2 and an altitude of 33,000 feet (10,000 m), landing at Edwards AFB. The result validated the SR-71/pod configuration.<ref name="first flight PR">{{cite press release|url=http://www.nasa.gov/centers/dryden/news/NewsReleases/1997/97-41.html|title=Linear Aerospike SR-71 Experiment Completes Successful First Flight (97-41)|author=Cast, Jim|date=31 October 1997| accessdate=14 July 2012|publisher=NASA}}</ref>

Five later flights focused on the experiment; two were used to cycle gaseous helium and [[liquid nitrogen]] through the experiment to check its plumbing system for leaks and to check engine operation characteristics. The first of these flights occurred 4 March 1998. The SR-71 took off at 10:16&nbsp;a.m. PST. The aircraft flew for 1:57 hour, reaching Mach 1.58 before landing at Edwards AFB.<ref name="NASA"/>

During three more flights in the spring and summer of 1998, [[liquid oxygen]] was cycled through the engine. In addition, two engine hot firings were conducted on the ground. Researchers decided against a hot-fire flight test because of liquid oxygen leaks in the test apparatus. The ground firings and the airborne [[cryogenic]] [[gas flow]] tests provided enough information to predict the hot-gas effects of an aerospike engine firing during flight.<ref name="last flight PR">{{cite press release|url=http://www.nasa.gov/centers/dryden/news/NewsReleases/1998/98-79_pf.html|title=LASRE Test Flights End, VentureStat Aerodynamic Performance Predicted (98-79)|date=20 November 1998|accessdate=14 July 2012|publisher=NASA}}</ref>

==LASRE hardware==

The experiment itself was a small, half-span model of a [[lifting body]] shape. The model contained eight thrust cells of an aerospike engine and was mounted on a housing known as the "canoe," which contained the gaseous [[hydrogen]], [[helium]], and instrumentation gear.<ref name="NASA"/>

The model, engine, and canoe together were called the "pod." The entire pod was 41 feet in length and weighed 14,300&nbsp;lb. The experimental pod was mounted on a NASA SR-71.<ref name="NASA"/>

==Hardware and aircraft==

Lockheed Martin may have used information gained from LASRE and the X-33 Advanced Technology Demonstrator to develop a potential future reusable launch vehicle. NASA and Lockheed Martin were partners in the X-33 program through a cooperative agreement.<ref name="NASA"/>

The goal of the X-33 program, and a major goal for NASA's Office of Aero-Space Technology, was to enable significant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that would improve U.S. economic competitiveness. The program implemented the National Space Transportation Policy, which is designed to accelerate the development of new launch technologies and concepts to contribute to the continuing commercialization of the national space launch industry.<ref name="NASA"/>

Both the X-33 and the smaller [[Orbital Sciences X-34|X-34]] technology testbed demonstrator were under the Space Transportation Program Offices at NASA Marshall Space Flight Center, Huntsville, AL. The air-launched, winged X-34 also was to demonstrate technologies applicable to future-generation reusable launch vehicles designed to dramatically lower the cost of access to space.<ref name="NASA">{{Cite web|url=https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-043-DFRC.html|title=NASA Armstrong Fact Sheet: Linear Aerospike SR-71 Experiment (LASRE) Project|last=|first=|date=6 August 2015|website=|archive-url=|archive-date=|accessdate=16 July 2017}} {{PD-notice}}</ref>

==References==
{{Reflist}}

==Further reading==
*[https://www.nasa.gov/centers/dryden/pdf/88598main_H-2280.pdf ''Flight Testing the Linear Aerospike SR-71 Experiment (LASRE)'' Sept 1998]

==External links==
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/120298main_FS-043-DFRC.pdf |title=NASA Facts - LASRE Project }}
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/88592main_H-2268.pdf |title=Linear Aerospike SR-71 Experiment(LASRE): Aerospace Propulsion Hazard Mitigation Systems }}
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/88652main_H-2380.pdf |title=Automated Testing Experience of the Linear Aerospike SR-71 Experiment (LASRE) Controller }} 
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/88649main_H-2377.pdf |title=Evaluation of the Linear Aerospike SR-71 Experiment (LASRE) Oxygen Sensor }}
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/88634main_H-2328.pdf |title=A Base Drag Reduction Experiment on the X-33 Linear Aerospike SR-71 Experiment (LASRE) Flight Program }}
*{{cite web|url= http://www.nasa.gov/centers/dryden/pdf/88650main_H-2378.pdf |title=Propellant Feed System Leak Detection—Lessons Learned }}

===Image gallery===
*[https://web.archive.org/web/20050311031826/http://www1.dfrc.nasa.gov/Gallery/Photo/SR-71-LASRE/index.html Photographs]
*[https://web.archive.org/web/20050307023325/http://www.dfrc.nasa.gov/Gallery/Movie/LASRE/index.html Movies]

[[Category:NASA vehicles]]
[[Category:NASA programs]]
[[Category:Lockheed Martin]]