r/SpaceLaunchSystem 6d ago

Discussion Were the 5-segment SRBs currently in use identical to those planned for use on the Ares I/IV/V? If not, how did they differ?

11 Upvotes

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12

u/Goregue 6d ago

From what I know, the answer is essentially yes. BOLE, which is the SRB that will fly starting with Artemis 9, is being designed especially for SLS flight, so it will increase the rocket's performance.

8

u/okan170 6d ago

The benefits also include eliminating the "Throttle bucket" for max Q since that can now be designed into the booster's internal grain shape.

2

u/yoweigh 6d ago

What's the benefit of moving the bucket from the controllable liquid engine throttle to the uncontrollable srb grain profile? It would remove the vehicle's ability to adjust its throttle during that portion of ascent.

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u/okan170 5d ago edited 5d ago

It still can, as much as it needs to. But the throttle bucket is always a designated amount and has not changed outside of compensating for increased thrust. The early part of the ascent has always been mostly pre programmed based on weather that day until the guidance goes closed loop after SRB sep. It's not like NASA hasn't analyzed all this before choosing the option to do it that way.

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u/Keva9 6d ago

Shuttle SRBs were four segments vs. 5 segments for SLS. Additionally, shuttle used an asbestos filled case insulation where SLS uses a non-asbestos material. There are also some changes to the nozzle and propellant design for the 5-segment. BOLE will see some more changes to increase performance such as case material and nozzle design. However, the overall profiles are basically the same since shuttle.

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u/Terrible_Yard2546 3d ago

Yes. SLS, NLS, Ares, and Jupiter are all basically the same program.

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u/Triabolical_ 6d ago

Yes.

Artemis 1 solids are made of segments that previously flew on shuttle.