vendredi 21 janvier 2022

ULA - Atlas V launches GSSAP-5 and GSSAP-6

 











ULA - Atlas V / USSF-8 Mission poster.


Jan 21, 2022

Atlas V carrying GSSAP-5 and GSSAP-6 liftoff

A United Launch Alliance (ULA) Atlas V 511 rocket launched the USSF-8 mission, two identical Geosynchronous Space Situational Awareness Program (GSSAP) satellites - GSSAP-5 and GSSAP-6 - for the U.S. Space Force, from Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida, on 21 January 2022, at 19:00 UTC (14:00 EST).

Atlas V launches GSSAP-5 and GSSAP-6

This is the 102nd mission for an Atlas V launch vehicle and the first and only planned flight of the Atlas V 511 configuration, the two-stage rocket with a single solid rocket booster.

Mission Overview

A ULA Atlas V 511 rocket launches the U.S. Space Force (USSF) - 8 mission for the U.S. Space Force’s Space Systems Command (SSC). USSF-8 launches two identical Geosynchronous Space Situational Awareness Program (GSSAP) satellites—GSSAP-5 and GSSAP-6—directly to a near-geosynchronous orbit approximately 22,300 miles (36,000 km) above the equator. Liftoff occured from Space Launch Complex-41 at Cape Canaveral Space Force Station, Fla.

GSSAP satellites are a space-based capability operating in a near-geosynchronous orbit supporting the U.S. Space Command space surveillance operations as a dedicated Space Surveillance network (SSN) sensor. These satellites provide neighborhood watch services in the Geosynchronous Earth Orbit (GEO) improving flight safety for all spacefaring nations operating in that orbit. Enhanced position knowledge of satellites at that distance improves the ability to warn a spacecraft owner/operator if there is another object anticipated to approach too closely and create a hazardous situation.  

Data from the GSSAP will uniquely contribute to timely and accurate orbital predictions, enhancing our knowledge of the GEO environment and further enabling space flight safety including satellite collision avoidance.

Unique to this mission is the first and only planned flight of the Atlas V 511 configuration. The 511 is the only unflown configuration in the Atlas family.

Launch Vehicle


Payload Fairing (PLF)

The spacecraft is encapsulated in a 17-ft (5-m) diameter short payload fairing. The 5-m PLF is a sandwich composite structure made with a vented aluminum-honeycomb core and graphite-epoxy face sheets. The bisector (two-piece shell) PLF encapsulates both the Centaur and the satellite. The vehicle’s height with the 5-meter short PLF is approximately 196 ft (59.7 m).

Centaur

The Centaur second stage is 10 ft (3 m) in diameter and 41.5 ft (12.6 m) in length. Its propellant tanks are pressure-stabilized and constructed of corrosion-resistant stainless steel. Centaur is a cryogenic vehicle, fueled with liquid hydrogen and liquid oxygen, powered by an RL10C-1 engine producing 22,900 lbs (101.8 kilo-Newtons) of thrust. The cryogenic tanks are insulated with a combination of helium-purged blankets, radiation shields and spray-on foam insulation (SOFI). The Centaur forward adapter (CFA) provides structural mountings for the fault-tolerant avionics system and structural and electrical interfaces with the spacecraft.

Booster

The booster is 12.5 ft (3.8 m) in diameter and 106.5 ft (32.5 m) in length. The booster’s tanks are structurally rigid and constructed of isogrid aluminum barrels, spun-formed aluminum domes and intertank skirts. Booster propulsion is provided by the RD-180 engine system (a single engine with two thrust chambers). The RD-180 burns RP-1 (Rocket Propellant-1 or highly purified kerosene) and liquid oxygen and delivers 860,200 lbs (3.83 mega-Newtons) of thrust at sea level. One solid rocket booster (SRB) generates the additional power required at liftoff, providing 371,550 lbs (1.6 mega-Newtons) of thrust. The Centaur avionics system, provides guidance, flight control and vehicle sequencing functions during the booster and Centaur phases of flight.
 
Flight Profile


United Launch Alliance (ULA): https://www.ulalaunch.com/

Images, Video, Text, Credits: Illustrations, photos and video footage Courtesy of United Launch Alliance/SciNews/Orbiter.ch Aerospace/Roland Berga.

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