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A United Launch Alliance Atlas 5 rocket made its third voyage up a launch pad in Cape Canaveral on Thursday, rolling into position for takeoff Friday afternoon with a classified payload for the U.S. government spy satellite agency.
The 206-foot (63-meter) high rocket made the 550-meter (550-meter) journey from ULA’s vertical integration facility to Cape Canaveral’s Complex 41 launch pad on Thursday afternoon. The Atlas 5 drove a mobile platform moved on locomotive rails.
Once the rocket was on pad 41, the automatic couplers connected the Atlas 5 to the ground systems. The ULA team planned to complete inspections, checkouts and other activities before the countdown begins on Friday.
Liquid oxygen will be loaded in the first stage during the countdown on Friday afternoon, along with liquid hydrogen and liquid hydrogen for the Atlas 5 Centaur upper stage. RP-1 fuel for the first stage has been loaded last month during a dress rehearsal of the countdown.
A forecast released Thursday morning by the US Space Force’s 45th Meteorological Squadron indicates a 90% chance of favorable weather conditions for launch at 5:13 PM EST (2213 GMT). The main meteorological concern is with the cumulus clouds at Cape Canaveral.
Meteorologists predict northerly surface winds of around 10-15 knots at launch, with some clouds at 3,000 feet. The temperature at launch should be around 76 degrees Fahrenheit.
The Atlas 5 mission, known as NROL-101, will launch a classified payload for the National Reconnaissance Office, which owns the US government’s fleet of intelligence-gathering surveillance satellites. Friday’s launch will mark the 86th flight of an Atlas 5 rocket since 2002 and the fifth Atlas 5 mission this year. It will be the 30th ULA mission for the NRO.
The NRO did not disclose information on the in-flight payload on the NROL-101 mission, but warnings issued to pilots and sailors suggest that the Atlas 5 rocket will head on a northeastern route from Cape Canaveral, following a path parallel to the coast. eastern United States first flying close to the Canadian maritime provinces.
The trajectory indicates that the Atlas 5 will release the NRO payload into a high tilt orbit.
The NRO has data transmission satellites and several spacecraft designed to intercept communication signals in Molniya-type elliptical orbits that extend nearly 40,000 kilometers above Earth at the highest points. These orbits are tilted about 63 degrees relative to the equator, giving the satellites regular views of Russia and other parts of the Northern Hemisphere.
The Atlas 5, scheduled for launch on Friday, could aim for a similar Molniya-type orbit, according to several independent experts monitoring the activity of spy satellites.
The launch vehicle for the NROL-101 mission will fly in the “531” configuration of the Atlas 5 with three solid rocket thrusters and a 5.4 meter diameter (17.7 ft) payload fairing.
The payload fairing for the NROL-101 mission will fly in its mid-length variant, offering more volume for the classified spacecraft on board than the standard 5.4-meter smaller diameter cover. The 5.4-meter medium-length fairing has flown in seven previous Atlas 5 missions.
The launch on Friday will be the fourth time that an Atlas 5 rocket will fly in the 531 variant, but it will be the first to be launched with the new GEM 63 boosters manufactured by Northrop Grumman. They have the same shape, fit and function as the AJ-60A solid rocket thrusters made by Aerojet Rocketdyne that have flown all previous Atlas 5 missions that required strap-on motors.
ULA originally relocated the Atlas 5 rocket to Platform 41 for the NROL-101 mission on November 2, but the teams returned the rocket to the VIF later the same day to replace an environmental control system duct that fed air conditioning to the payload. on top of the vehicle launch.
The Atlas 5 returned to the launch pad on November 3 for a launch attempt on November 4, which ULA cleaned up due to a problem with the valves in the ground liquid oxygen system at platform 41.
ULA then moved the Atlas 5 back into the VIF to shelter from tropical storm Eta, which moved off the northeastern coast of Florida on Thursday and headed into the Atlantic Ocean, clearing the way for the rocket to return. new to platform 41 in preparation for Friday launch opportunity.
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Follow Stephen Clark on Twitter: @ StephenClark1.
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