The highly modified Gulfstream II plane (N178B c/n 125 and N74A c/n 36) which are operated by the Missile Defense Agency (MDA) was spotted in Anchorage, Alaska.

Aviation enthusiast Markymark has released photos showing unique versions of American twin-engine business jet designed Gulfstream Aerospace during a visit to Anchorage.

”Missile Defense Agency modified Gulfstream II N178B used as a High Altitude Observatory platform based out of Tulsa, OK parked this evening at Ross Aviation.,” Trump said on Twitter.

For use as “High Altitude Observatory” platform, the Gulfstream II plane has been modified by the addition of a large front dorsal fairing, housing the Electro-optical / Infrared Systems (EO/IR) sensors.

This aircraft has a maximum altitude of 45,000ft, a range of 3,000nm and a cruising speed of 460kts. They are powered by two, rather noisy, Rolls Royce Spey engines which have a thrust of 11,400lb each.

The Missile Defense Agency (MDA) is a research, development, and acquisition agency within the Department of Defense. MDA’s workforce includes government civilians, military service members, and contractor personnel in multiple locations across the United States.

The Missile Defense Agency is partially or wholly responsible for the development of several ballistic missile defense (BMD) systems, including the Patriot PAC-3, Aegis BMD, THAAD and the Ground-Based Midcourse Defense system.

Missile Defense Agency modified Gulfstream II N178B used as a High Altitude Observatory platform based out of Tulsa, OK parked this evening at Ross Aviation. Thanks @DWHonan for the heads up #avgeek #aviationdaily #planespotting #aviation pic.twitter.com/QcnZ5PKHx1

— Markymark (@Fiicaan) July 3, 2019

If it wasn’t for @DWHonan I’d never have known this highly modified Missile Defense Agency Gulfstream II was headed to Anchorage. Seems like it’s spending a night#avgeek #aviationphotography #aviationdaily #planespotting #pilot pic.twitter.com/71aOoGozmC

— Markymark (@Fiicaan) July 3, 2019