This certainly put a dent in the narrative that SLS was forced on NASA by congress. If what you said is true, then certain elements inside NASA is just as responsible for the current mass as congress, if not more so.
I guess this is NASA HSF's biggest problem, they're eternally optimistic about the budget.
Yes, the smaller version of Direct would have used the existing 4 seg boosters from the Shuttle fleet. It would use 3 RS-25's instead of the current 4, and could grow and stretch (later) to 4 or 5 engines, with a J2X upper stage. The smaller version could have been fielded several years ago, and delivered 70 tons to orbit. 70 tons, with in space assembly could have done a lot, and be launched with current budget about 6 times a year. Also, without the long delay that we had.
Looking backwards, Bob you are correct. They could have had side-mount back in the 90's and got 50-60 tons to LEO, and still kept the shuttle fleet for human transportation. At that point they could have beefed up the shuttle making the nose an escape pod to avoid a Challenger situation. Maybe even escape during orbit re-entry also. The side-mount could have delivered modules, cargo, and satellites, while the beefed up shuttle could deliver humans. Oh well, we got SLS whenever it gets built. However by then SpaceX and BO will be delivering things with reusable first stages at least, and BFR/BFS will be coming along. SLS will then be too big to operate efficiently.
I really can't comprehend why a side-mount STS cargo-carrier wasn't built, using almost off-the-shelf STS elements. Or why Shuttle-C wasn't pursued inj the first place. Sigh.
They could have had side-mount back in the 90's and got 50-60 tons to LEO, and still kept the shuttle fleet for human transportation.
...I do agree there are many decisions I think NASA would admit would do differently knowing how things panned out, however having said that they have created a remarkable launch vehicle and spacecraft. ...
Quote from: Bubbinski on 12/07/2017 01:12 amIf this thing about 2023 is indeed valid, what would be driving this delay from 2019-20? Job security for Shelby's Alabama-based workers. SLS is, after all, little more than a massive jobs program at this point.
If this thing about 2023 is indeed valid, what would be driving this delay from 2019-20?
Quote from: spacenut on 01/01/2018 01:26 pmAren't the engines built in Alabama, the planning and design team is in Alabama. The RS-25 engines were built, and are being reengineered and tested, in Mississippi. The ICPS was built in Alabama at the ULA plant in Decatur. The RL10 was probably built in Florida, but I'm not certain. The SLS core stage tank parts were made in Germany and welded together in Louisiana on a machine assembled by a Swedish company. MSFC's primary involvement is in structural testing and avionics, I believe. Alabama, by the way, now has one senator from each party. - Ed Kyle
Aren't the engines built in Alabama, the planning and design team is in Alabama.
The work is mainly conducted at two Aerojet Rocketdyne centers. The machining, welding, assembly and test of subassemblies takes place at its Canoga Park, California Strategic Fabrication Center. Turbopump assembly takes place at the West Palm Beach, Florida facility. Testing then takes place at Stennis.
Quote from: Khadgars on 12/31/2017 06:07 pm...I do agree there are many decisions I think NASA would admit would do differently knowing how things panned out, however having said that they have created a remarkable launch vehicle and spacecraft. ...1. 'Have created' is incorrect tense.2. In what ways are either spacecraft (capsule) or rocket 'remarkable?'
Clongton mentioned in another thread that SLS is more or less DIRECT's Jupiter Heavy 244. Presuming similar motivations, How did SLS come to end up with such a large core stage?
(c) MINIMUM CAPABILITY REQUIREMENTS.—(1) IN GENERAL.—The Space Launch System developed pursuant to subsection (b) shall be designed to have, at a minimum, the following:(A) The initial capability of the core elements, without an upper stage, of lifting payloads weighing between 70 tons and 100 tons into low-Earth orbit in preparation for transit for missions beyond low-Earth orbit.(B) The capability to carry an integrated upper Earth departure stage bringing the total lift capability of the Space Launch System to 130 tons or more.(C) The capability to lift the multipurpose crew vehicle.(D) The capability to serve as a backup system for supplying and supporting ISS cargo requirements or crew delivery requirements not otherwise met by available commercial or partner-supplied vehicles.(2) FLEXIBILITY.—The Space Launch System shall be designed from inception as a fully-integrated vehicle capable of carrying a total payload of 130 tons or more into low-Earth orbit in preparation for transit for missions beyond low-Earth orbit. The Space Launch System shall, to the extent practicable, incorporate capabilities for evolutionary growth to carry heavier payloads. Developmental work and testing of the core elements and the upper stage should proceed in parallel subject to appro- priations. Priority should be placed on the core elements with the goal for operational capability for the core elements not later than December 31, 2016.(3) TRANSITION NEEDS.—The Administrator shall ensure critical skills and capabilities are retained, modified, and devel- oped, as appropriate, in areas related to solid and liquid engines, large diameter fuel tanks, rocket propulsion, and other ground test capabilities for an effective transition to the follow- on Space Launch System.(4) The capacity for efficient and timely evolution, including the incorporation of new technologies, competition of sub-ele- ments, and commercial operations.
Quote from: RotoSequence on 12/29/2017 10:10 amClongton mentioned in another thread that SLS is more or less DIRECT's Jupiter Heavy 244. Presuming similar motivations, How did SLS come to end up with such a large core stage?To directly answer your question about large core: there was a push to employ 5 seg SRBs (and 5 seg SRBs require a longer core stage than was used for STS). One can assume that it was ATK pushing for the 5 seg, but I don't know for sure the drivers and decision-makers that insisted on 5 seg.
So, what can be done to improve SLS and make it work at a lower cost? Fly-back liquid boosters?, liquid boosters? A good second stage?
Quote from: spacenut on 01/02/2018 02:34 pmSo, what can be done to improve SLS and make it work at a lower cost? Fly-back liquid boosters?, liquid boosters? A good second stage?To make the SLS economical to operate and generally useful, NASA needs to do what it did with Transhab. It sold the rights to Bigelow Aerospace who turned it into something that is economical and useful. Get the government *and* the government contractors out of the SLS business entirely and maybe, just maybe, something could be done by a well positioned commercial company to make the vehicle useful and less expensive to operate.In such a situation, the 1st thing I would recommend is to replace the SRB's with human rated reusable LRB's, similar to the Falcon 9 1st stage. That LRB, when equipped with a 2nd stage, should be capable of putting a fully fueled and outfitted Orion spacecraft into LEO.Do that and we'd have something generally useful that could be operated at a reasonable cost.
Is it too late to change directions?
They initially were trying to keep the existing shuttle work force, but that didn't work out. Too long from shuttle decommissioning to SLS launching. Also not enough SLS launches to justify a work force with only one launch a year.
Quote from: spacenut on 01/02/2018 02:34 pmSo, what can be done to improve SLS and make it work at a lower cost? Fly-back liquid boosters?, liquid boosters? A good second stage?To make the SLS economical to operate and generally useful, NASA needs to do what it did with Transhab. It sold the rights to Bigelow Aerospace who turned it into something that is economical and useful. Get the government *and* the government contractors out of the SLS business entirely and maybe, just maybe, something could be done by a well positioned commercial company to make the vehicle useful and less expensive to operate.In such a situation, the 1st thing I would recommend is to replace the SRB's with human rated reusable LRB's, similar to the Falcon 9 1st stage. That LRB, when equipped with a 2nd stage, should be capable of putting a fully fueled and outfitted Orion spacecraft into LEO. Reserve the HLV for cargo only and use the boosters as reusable Orion launchers.Do that and we'd have something generally useful that could be operated at a reasonable cost.
Wow, what a difference 10 years makes. 10 years ago, we were talking about Direct vs Constellation. Which was the cheaper alternative and the quicker alternative. Direct was of course. We ended up getting SLS. Now, 10 years later no rocket has flown, and it may be a few more years to flight at over $1 billion a pop.