[khuey]

> We modernized and rationalized the Space Shuttle to make the SLS and each SLS costs > $4B.

Except we didn't, because we took absurdly high-end engines (RS-25s) that were designed for reuse and refurbishment and now we drop them in the ocean after every launch.

[BuyMyBitcoins]

And because we are using those engines, which lack sufficient thrust at liftoff, we have to use the Solid Rocket Boosters. Those were supposed to be recoverable but the SLS just drops them into the ocean now too.

[tim333]

I found on a forum

>it would cost $23 million to refurbish a used SRB and $12~70 million to refuel it.

A unconfirmed sources, that worked at NASA claim that Thikol employee explained to him. That reuse cost 3 time more, than a expendable SRB https://forum.nasaspaceflight.com/index.php?topic=51959.0

[Dalewyn]

Space Shuttle (and now SLS) SRBs always dropped into the ocean for recovery after the fact.

[mikepurvis]

I think it’s actually a bit more nuanced than that, see:

https://space.stackexchange.com/a/45894

Basically the SRB had multiple modules and some were more reusable than others, so some got recovered and refurbished a lot more.

[Aloha]

AFAIK, we do recover and refurbish them - at least when shuttle was flying.

[Polizeiposaune]

Not any more. SLS drops them in the ocean.

[jasongill]

So did the Shuttle; all of the Shuttle SRB's were recovered (with one obvious exception) and refurbished and reused at least in part. It wouldn't make sense for either Shuttle or SLS to drop them on the ground

[V99]

The two solid rocket booster casings are dropped into the ocean and (usually) recovered with both the Shuttle and SLS.

RS-25s were the three main engines. They were very expensive, designed for reuse and were recovered with the rest of the orbiter they were bolted on to. Not in the ocean. Then refurbished with a much greater amount of effort and money than initially expected, and eventually reused on a future mission..

But the SLS first stage doesn't fly itself back to Cape Canaveral after 2 weeks like the Shuttle orbiter did. So those now FOUR very expensive "reusable" engines are now chucked into the ocean never to be seen again.

[Polizeiposaune]

They've given up on refurbishing & refueling the SRB casings for the SLS.

[Polizeiposaune]

The shuttle did not drop RS-25's in the ocean. The SLS does.

The shuttle's SRB's were fished out, refurbed, refueled, and reflown.

The SLS's SRB's are left to sink to the bottom.

[bpodgursky]

And yet, the SLS does.

[marcellus23]

He's talking about the SLS. The shuttle hasn't flown in 13 years.