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Minotaur IV charges to orbit

July 15th at 9:46 AM EST after a short delay, Northrop Grumman's Minotaur IV rocket charged into orbit from MARS- Mid-Atlantic Regional Spaceport's pad 0B on Wallops Island, Virginia.

Sunrise over Pad 0B and the Minotaur IV rocket on July 15th 2020

Slated to launch at 9:00 AM est, local fisherman caused a forty six minute delay when they unknowingly had their boat inside the launch hazard zone. The countdown, which was stopped at T-minus sixteen minutes resumed, and the rocket blasted off at 9:46 AM est on it's top secret mission with four payloads for the National Reconnaissance Office, or NRO after the boat was cleared.

Launching after a 46 minute delay the Minotaur IV took flight from Pad 0B

Named NROL-129 this was the first U.S. Space Force mission from Wallops Flight Facility. Also this was NRO's first dedicated mission there as well. The 78 foot tall Minotaur IV rocket, a former peacekeeper ICBM (Intercontinental Ballistic Missile) made between 1988-1990 which was then on alert in a silo for 15 years until the military decommissioned the Peacekeeper missiles in 2005. the rocket consists of three solid fuel motors that were decommissioned and left in storage for some years along with an upper stage commercially built by Northrop Grumman. Made up of an SR-118 solid moter, the first stage delivers 2,200 kN of thrust, then the second stage, the SR-119 takes over delivering 1,365 kN of thrust before handing things over to the SR-120 motor which delivered 329 kN of thrust before the Northrop Grumman 4th stage takes over to deliver the payloads to the correct orbit, which is unknown due to the classified nature of this mission

Incredibly these rockets reach supersonic speeds, meaning it breaks the speed of sound around 20 seconds after ignition. This is with a max payload capacity of 3814 lbs. In comparison it takes around 88 seconds for a Falcon 9 SpaceX rocket to reach supersonic speeds. The Minotaur IV reaches full thrust is almost instantaneous at just 0.2 of a second after ignition. There is a large difference from using liquid propellant, and a lot less factors in place to slow doing the acceleration process.

NROL-129 breaking the sound barrier


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