US Air Force’s X-37B Space Plane Ready for Launch, Carrying Experimental Payloads

US Air Force’s X-37B Space Plane Ready for Launch, Carrying Experimental Payloads

Wednesday, May 20, shall witness the fourth launch of the US Air Force’s guarded, unmanned, X-37B space plane. It will carry, not just US national security experimental payloads but also experimental payloads sponsored by NASA and solar sailing LightSail test from the Planetary Society.

The Launch Readiness Review was completed on Monday and the robotically controlled X-37B will takeoff using a two-stage United Launch Alliance (ULA) Atlas V 501 rocket on the AFSPC-5 mission. The launch, just like the previous three launches, shall take place from the Space Launch Complex (SLC)-41 at Cape Canaveral Air Force Station, Florida, at some point during a four-hour launch window that opens at 10:45 AM EDT and extends until 2:45 PM EDT on May 20. The four-hour window has been kept with the hope of getting acceptable launch conditions sometime during the lengthy period. As of now, a positive development has been a weekly rise from 40 percent to 60 percent, with respect to the likelihood of favorable weather conditions for the launch.

X-37B is the second Orbital Test Vehicle (OTV) built by Boeing. It is an unmanned reusable mini shuttle, much like the miniature version of NASA’s space shuttles. Currently, this advanced reentry spacecraft is fling on the OTV-4 mission. This is aptly called a ‘space plane’ as it is launched vertically like a satellite but lands horizontally like an airplane. It weighs about 11,000 pounds and is powered by Gallium Arsenide Solar Cells with Lithium-Ion batteries.

What distinguishes the present flight is the purpose it intends to fulfill. Unlike the first three launches that were aimed at checking out vehicle capabilities and reentry systems, the present launch is focused towards research, on testing experimental payloads.

Though the precise launch time has not been disclosed, one can watch the Atlas launch live on the website ‘’, where the ULA webcast will begin from 10:45 AM onwards.

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