View source for ATLAS-I

{{Distinguish2|the [[Atlas I]] [[intercontinental ballistic missile]]}}
[[File:US_Air_Force_-_Sandia_National_Laboratory_-_TRESTLE_Electromagnetic_Pulse_Test_Apparatus.jpg|thumb|A Boeing [[B-52]] strategic bomber being prepared for EMP testing at TRESTLE in 1982.]] '''ATLAS-I''' (Air Force Weapons Lab Transmission-Line Aircraft Simulator), better known as '''TRESTLE''', or simply '''the Trestle''', was the [[codename]] for a unique [[electromagnetic pulse]] (EMP) generation and testing apparatus built between 1972 and 1980 during the [[Cold War]] at [[Sandia National Laboratories]] near [[Kirtland Air Force Base]] in [[Albuquerque]], [[New Mexico]].<ref>Giri, D.V. Ph.D. [http://www.ece.unm.edu/summa/notes/trestle.html "The notes of Dr. Carl E. Baum"].  Retrieved August 8, 2011.</ref>

ATLAS-I was the largest [[NNEMP#Non-nuclear_electromagnetic_pulse|NNEMP]] (Non-Nuclear Electromagnetic Pulse) generator in the world, designed to test the [[radiation hardening]] of strategic aircraft systems against EMP pulses from [[nuclear warfare]]. Built at a cost of $60 million, it was composed of two parts: a powerful [[Marx generator]] capable of simulating the effects of a a [[high-altitude nuclear explosion]] (HANE) of the type expected during a global nuclear war, and a giant wooden [[trestle]] built in a bowl-shaped [[Arroyo (creek)|arroyo]], designed to elevate the test aircraft above ground interference and orient it below the pulse in a similar manner to what would be seen in mid-air.<ref>Yang, F.C. Lee, K.S.H. (July 1980). [http://www.ece.unm.edu/summa/notes/SSN/note267.pdf "Analytical representation of ATLAS I (Trestle) Fields"] (PDF). [[University of New Mexico]]. Retrieved August 8, 2011.</ref>

TRESTLE is the world's largest structure composed entirely of wood and glue laminate.<ref>[http://www.brookings.edu/projects/archive/nucweapons/trestle.aspx "U.S. Nuclear Weapons Cost Study Project: The Trestle Electromagnetic Pulse Simulator"]. [[Brookings Institution]]. Retrieved 8/8/2011.</ref>

==EMP generator==
[[File:TRESTLE EMP simulator - B1B Bomber - Kirtland Air Force Base - 1989.jpeg|thumb| A Rockwell [[B-1B]] strategic bomber is readied for testing at TRESTLE in 1989. Note the elevated Marx generator to the right, the aircraft platform in the center, the sensor towers to the sides of the platform and the resistive termination tower at the rear.]]
The Marx generator providing the EMP pulse generated 200 [[gigawatt]]s of electromagnetic flux at an [[electrical potential]] of 10 [[megavolt]]s,<ref name="reuben"/> powerful enough to reliably reproduce (at short range) the deleterious effects of a [[thermonuclear explosion|thermonuclear detonation]] on electronic circuitry as created by such examples as the [[Hardtack I|HARDTACK I]], [[Operation Argus|ARGUS]] and [[Operation Dominic I and II|DOMINIC I]] ([[Operation Fishbowl]]) high altitude nuclear tests. The generator itself was mounted at the end of a long, diagonal wooden scaffold structure, located above and to one side of the aircraft platform, with the primary receiving tower located at equal elevation on the other side of the arroyo.

Due to their higher flight altitude and nuclear [[payload]], [[Strategic Air Command]] bombers were the primary object of the tests, but fighters, transport aircraft and even missiles were also tested for EMP hardness on TRESTLE. In addition to electronics survivability tests, numerous sensors located beneath and to the sides of the aircraft would gather additional data on the airframe's EMP permeability to be used in design considerations for future Cold War aircraft.

The advances made in EMP generation technology by Sandia during the operation of TRESTLE greatly assisted in the construction of the much more powerful 40 [[megavolt]], 50 [[terawatt]] (50,000 gigawatt) [[Z Machine]] at Sandia during the 1990s. Technological advances during the 2000s have since boosted this output to 290 terawatts (290,000 gigawatts), high enough to actually study [[nuclear fusion]] at the point of detonation.<ref>[http://www.sandia.gov/media/z290.htm "Another dramatic climb toward fusion conditions for Sandia Z accelerator"]. [[Sandia National Laboratories]].  Press release. March 2, 1998. Retrieved August 8, 2011.</ref>

==Trestle structure==
The primary wooden structure of TRESTLE was 1,000 feet long, 600 feet (12 stories) tall, and constructed of 6.5 million board-feet of lumber,<ref name="reuben">Reuben, Charles. (January 6, 2011). [http://alibi.com/news/35291/Empire-My-Prince.html "In Memoriam: Empire My Prince: Carl Baum, trestle-maker"]. ''[[Weekly Alibi]]'', V. 20 No. 1. Alibi.com. Retrieved August 8, 2011.</ref> sufficient to support a fully loaded [[B-52]] (then the largest and heaviest [[strategic bomber]] in the US inventory) while also minimizing any chance of interference from the ground or the structure itself, creating a reasonable simulation of airborne conditions. A mix of [[Douglas Fir]] and [[Southern Yellow Pine]] were used for the timbers,<ref name="reuben"></ref> as both showed excellent EMP transparency with the former having the best tensile strength and the latter the best weather resistance. By using an all [[glued laminated timber]] structure and nail-free [[woodworking joints]] to hold the giant timbers together, measurements from the EMP tests would not be skewed by [[ferrous]] nails or braces in the structure. Even the [[fire escape]] along one side of the trestle and the massive [[lag bolt]]s holding the load-bearing beams in place were entirely composed of wood and [[fiberglass]].

==Current status==
The ATLAS-I program was shut down in 1991 after the end of the Cold War brought an end to [[destructive testing|destructive]] EMP testing of aircraft, being replaced by far cheaper [[computer simulations]] as technology improved. Despite going without maintenance for over 20 years, the wooden trestle structures are all still standing and it remains the biggest metal-free wood laminate structure in the world.<ref name="reuben"/> The trestle has, however, become a significant fire hazard since the [[creosote]]-soaked wood has dried considerably in the desert conditions and the automatic [[fire sprinkler system]] was deactivated in 1991. Efforts are underway to secure the funding necessary to have the structure protected as a [[national historic landmark]], although efforts are complicated by the [[top secret]] nature of the Sandia/Kirtland facility it is situated on.

==See also==
*[[Radiation hardening]]
*[[High-altitude nuclear explosion]]
*[[Starfish Prime|STARFISH Prime]]

==References==
{{reflist}}

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[[Category:Cold War]]
[[Category:Cold War military equipment of the United States]]
[[Category:Equipment of the United States Air Force]]
[[Category:Pulsed power]]
[[Category:Electronic test equipment]]
[[Category:Military facilities in New Mexico]]
[[Category:2Fix]]