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Daily archives "August 15, 2016"

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USAF AFSPC-6 / ULA Delta IV mission update

The USAF's AFSPC-6 payload is raised to be mated with a ULA Delta IV rocket. Credit: ULA

The USAF’s AFSPC-6 payload is raised to be mated with a ULA Delta IV rocket. Credit: ULA

Everything is progressing towards the scheduled launch of the United States Air Force’s AFSPC-6 mission atop a United Launch Alliance (ULA) Delta IV on Friday, August 19, 2016. Set to lift off from SLC-37 at Cape Canaveral Air Force Station (CCAFS) in a 4-hour window beginning at 12:00 am, the dual Orbital ATK-built satellite payload is already encapsulated in a 4-meter diameter fairing, and will be delivered to a near-geosynchronous orbit.

The L-4 weather forecast currently indicates a 20% chance of violating weather launch constraint criteria, with the primary concern being cumulus clouds. Should a 24-hour delay be necessary, the following day’s forecast is essentially identical.

Check back with The Liftoff Report for updates.

NASA readies for another test of SLS’s core propulsion system

NASA conducts a static fire test of one of its RS-25 engines. Credit: NASA

NASA conducts a static fire test of one of its RS-25 engines. Credit: NASA

NASA is preparing to conduct a full-duration static test fire of one of its RS-25 engines on Thursday, August 18, four of which will comprise the propulsion system in the agency’s Space Launch System (SLS) heavy-lift rocket. Previously known as the Space Shuttle Main Engine (SSME), the uprated engine will initially provide up to 109% of its original design thrust in early iterations of SLS, with a goal of eventually being rated for 111%.

When the engines were used on the Space Shuttle, they were rated for nominal use at 104.5%, though could be throttled up to 109% in the event of an abort scenario. However, doing so ran the risk of significant degradation of engine components, perhaps to the point of making it not cost-effective to refurbish the engine. That’s not a concern with SLS, though, as the core stage will not be recovered after use.

In order to consistently run the engine at the higher performance levels, Aerojet Rocketdyne – the manufacturer of the SSME/RS-25 engine – needed to upgrade the engine controller. The now-mothballed J-2X engine, also manufactured by Aerojet Rocketdyne, provided the perfect platform from which to develop the engine control module for the RS-25. Numerous development test firings have validated the new controller, as well as other changes to the engine, and NASA now moves forward with running the flight engines through mission-like static fire tests in preparation for the maiden launch of SLS, scheduled for the latter half of 2018.

Infographic explains why testing the RS-25 is necessary. Credit: NASA

Infographic explains why testing the RS-25 is necessary. Credit: NASA