SLS: Shuttle vs Saturn V - FIGHT!

[MKSheppard]

Link

With a Shuttle Derived (SD) Heavy Lift Launch Vehicle (HLV) still leading the way via ongoing evaluations into the configuration of the Space Launch System (SLS), an evolvable vehicle – which can be delivered on time and on cost – is undergoing final refinements. It is understood that the only real competitor at this stage is based around a Saturn V heritage HLV, using LOX/RP-1-powered F-1 engines.

....

RAC-2′s leading vehicle configuration for the SLS is a Saturn V class vehicle, sporting a LOX/RP-1 first stage, with either a LOX/RP-1 or LOX/LH2 second stage. This vehicle is classed as being based around a highly extensible, adaptable and capable architecture, one which is very modular by design.

Indeed, it should be noted that the HEFT/HEAT evaluations are not just based around the HLV, but also the entire architecture of NASA’s future exploration goals.

Less is known about this vehicle other than advances have been made in negotiating around the problem of the required new large LOX/RP-1 engine, by literally using what is understood to be a good quantity of unused F-1 engines from the Saturn V program for the opening flights.

Sources – notably from the “rival” RAC-1 camp – have claimed there would be problems with this configuration, centered on the certification of the heritage engine and the development of an all new airframe, although supporters of the RAC-2 candidate are buoyant about all aspects of the vehicle and the capability it would bring.

RAC-2 supporters have also cited performance and capability advantages over the SD HLV option.

Some pad infrastructure also remains in place for this Kerolox option at the Kennedy Space Center (KSC), with the RP-1 fuel line abandoned in place for the last 30 years since the Saturn V last launched out of Florida.

However, recent photographs of the plumbing shows the supporting stanchions have suffered badly over the years – mainly from being exposed to SRB residue from the Shuttle launches.

This vehicle option also suffers politically, given it does not comply with the Authorization Act’s request to utilize Shuttle and CxP hardware, which was acknowledged by NASA’s preliminary report. “For the SLS, the Agency has decided to use a Reference Vehicle Design that is derived from Ares and Shuttle hardware, given the Congressional direction.”

Rocketdyne produced 98 production F-1 engines. Of those, 65 were launched. That means that there are about 30 production engines in existence.

Back in 2005 Rocketdyne studied F-1 restart. Costs were $400m to restart the line, and $20m per engine at 10-12 engines a year.

Rocketdyne for HEFT estimated that it would cost $600m to restart the RS-25D (SSME) line, and then another $600~ million to develop a cheep expendable RS-25E variant. Costs are around $40-80m per RS-25.

It comes down to expending $100 to $140 million of RP-1 engines or $300 million plus of LH2 engines each flight.

If you fly the SLS twice a year, that adds up to about $4.5 billion extra cost over fifteen years of operation (30 launches) for engines, since you don't get them back like with Shuttle.

Moreover; 5 x RS-25s give you about 2 mlbf of thrust. In order to meet payload requirements, this virtually means you have to use a pair of SRBs to make up the remainder of sea level thrust needed (5.6 mlbf).

The SRBs impose serious logistical problems on the integration/transport complex at KSC. For one, you can't use a lot of VAB space for various purposes because it's a danger zone when the SRBs are in the building.

A pair of SRBs also weigh 1,180 tonnes. By contrast, the entire Saturn V stack weighed about 200 tonnes when it was being transported to the Pad by the crawler.

They were planning on upgrading the crawlerway and buying new crawlers or severely upgrading the present ones for Ares V's significant empty weight.

Plus, at extremely low flight rates, the SRBs are just a horrible wash, due to the huge complex needed to support and refurbish them after each flight, including those two ships that go out and recover them.

So yeah, somewhere von Braun is laughing. Fucking laughing, as the Brags would be.

[Uraniun235]

Just out of curiosity, what sort of flight schedule would be needed to make the SRBs cost-effective?

Also, I can't remember if I asked this before (a search isn't turning up anything) but is there a substantial cost difference between RP-1 and LH2?

[MKSheppard]

Just out of curiosity, what sort of flight schedule would be needed to make the SRBs cost-effective?

50 flights a year was the original design basis for all the costing done for STS.

Also, I can't remember if I asked this before (a search isn't turning up anything) but is there a substantial cost difference between RP-1 and LH2?

2001 -- $0.09/pound of LO2 (LOX)
2010ish -- $0.56/pound of RP-1.
2010 -- $2.49/pound of LH2.
1980s - $2.50 lb for PBAN (Shuttle SRBs) at 4 million pounds a year. ($4.92/lb if you adjust for inflation from 1985 to 2011 dollars)

This ties into a future concepts booklet I found from 1962 that said:

It is also obvious that the trend toward the reusable vehicle concept does favor the liquid rocket systems rather than the solid propellant engines. While the solid system might offer an alternate method to gain large payloads fast, it does not seem competitive with the reusable liquid vehicle in the long run. This is obvious when one considers the fact that solid propellants cost one dollar/lb, and liquid propellants two to five cents/lb or, for high energy liquids, up to 25 cents/lb, Propellant costs become a dominant factor for vehicles with high reusability rates.

[someone_else]

It is understood that the only real competitor at this stage is based around a Saturn V heritage HLV, using LOX/RP-1-powered F-1 engines.

Well, that was somewhat obvious from the beginning.

This vehicle option also suffers politically, given it does not comply with the Authorization Act’s request to utilize Shuttle and CxP hardware, which was acknowledged by NASA’s preliminary report. “For the SLS, the Agency has decided to use a Reference Vehicle Design that is derived from Ares and Shuttle hardware, given the Congressional direction.”

Yay! Let's waste billions running around in circles trying to reinvent the wheel!
I hope it doesn't end up like crap again.

is there a substantial cost difference between RP-1 and LH2?

RP-1 is also much easier to design stuff working with it, not being cryogenic. It is also much denser than liquid hydrogen, so you can make a much smaller (thus lighter) fuel tank and a slimmer, more streamlined, rocket (less air drag).

[MKSheppard]

RP-1 is also much easier to design stuff working with it, not being cryogenic.

Technically, it's semi/partially cryogenic. You still need LOX for oxidizant. But yes, much less of a chore than LH2.

[SirNitram]

Naturally, I'm hoping the SatV derived lifter wins. The shuttle was a crippled brick.

[Skgoa]

We aren't talking about a new shuttle. The open question is with which of their two existing engines NASA decides to build its next rocket. Both have advantages and disadvantages, if the last years are an indicator it will mostly be a political decision, anyways.

[someone_else]

A more interesting open question is that if they expect anyone other than NASA (basically themselves) using this rocket. Because that's one of the various reasons that sunk the Shuttle (thinking of it as THE solution to bring stuff in orbit for everyone in the world when it was clearly uneconomic).

Btw, wasn't "STS" the acronym for Senator Launch System? (used by Shep in the title)

[SirNitram]

We aren't talking about a new shuttle. The open question is with which of their two existing engines NASA decides to build its next rocket. Both have advantages and disadvantages, if the last years are an indicator it will mostly be a political decision, anyways.

Yes, and the SatV's engine still got heavier things higher, IIRC. As for the political part, no duh. Senator Richard Shelby has decided even after NASA decided it was not their path, even after it's cancelled, NASA has to spend money on Ares. However you felt about the platform, it's dead, and he's just greedily shovelling money into a pit.

[PeZook]

Actually, Saturn lofted a comparable total amount of mass to a comparable orbit, it's just that the Shuttle uses 80% of its payload for the orbiter.

The great argument for a new Saturn is the cost analysis, with the F-1 engine two to three times cheaper than a modernized and expendalized SSME.

Of course that's according to the producer ; It may yet turn out that some unforeseen cost overruns etc. raise the price, but it does look really good on paper.

Hell...there's really not much stopping NASA from using some Shuttle tech and accomodating an F-1 derived engine into the result, if some politicos feel they should do that.

[Skgoa]

Spending bill will put an end to the Constellation program
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: April 14, 2011


A federal budget bill passed Thursday by the U.S. Congress will loosen restrictions on NASA efforts to shut down the Constellation moon program and start work on fresh launch and exploration vehicles.


NASA's budget is set at $18.45 billion this year in the long-awaited federal spending bill, approximately $250 million less than last year's funding level.

The legislation pays for NASA operations through the end of September, when Congress could face another heated budget battle on federal spending for fiscal year 2012.

Congress sent the budget bill to the White House, where President Obama was expected to sign it into law before the government's account runs dry Friday night.

The bill was hammered out between President Obama and leaders in the House and Senate after a failure to agree on budget cuts nearly forced a government shutdown last week. Named H.R. 1473, the bill cuts $38 billion from the overall federal budget for fiscal year 2011, which expires Sept. 30.

Since Oct. 1, NASA and other federal agencies have been operating under a series of short-term budget bills called continuing resolutions. Thursday's bill is another continuing resolution, but it will run for nearly six months.

Perhaps more important than NASA's top-line budget number, the bill permits NASA to formally end the terminated Constellation moon program and redirect efforts toward a new heavy-lift rocket and multipurpose crew vehicle, fresh exploration programs that will likely recycle substantial work from Constellation.

Previous law barred NASA from restructuring its budget to shut down the Constellation program, which was recommended to be cancelled by the Obama administration in February 2010. Lawmakers agreed to end the program in a budget blueprint authorization act signed into law in October.

But Congress never passed a long-term spending bill until Thursday, meaning the restrictive language from last year's budget remained the law of the land despite agreements to end Constellation.

The language was put in last year's budget by Sen. Richard Shelby, R-Ala., whose state is home to many jobs in the Constellation program.

"Among other things, this bill lifts funding restrictions that limited our flexibility to carry out our shared vision for the future," NASA Administrator Charles Bolden said in a written statement. "With this funding, we will continue to aggressively develop a new heavy-lift rocket, multipurpose crew vehicle and commercial capability to transport our astronauts and their supplies on American-made and launched spacecraft."

NASA's inspector general reported in January that NASA was spending a rate of more than $575 million per year on Constellation projects the agency would have otherwise considered canceling or scaling back. By some accounts, NASA may have already spent nearly $300 million on such unnecessary work since fiscal year 2011 began Oct. 1.

H.R. 1473 provides $3 billion for NASA's new exploration program, including $1.8 billion for the Space Launch System heavy-lift rocket and $1.2 billion for a crew capsule. Spending on those vehicles are in line with the NASA authorization act, a tentative spending plan passed last year by the previous Congress.

"We appreciate the work of Congress to pass a 2011 spending bill," Bolden said. "NASA now has appropriated funds to implement the 2010 authorization act, which gives us a clear path forward to continue America's leadership in human spaceflight, exploration and scientific discovery."

What's missing in the budget is a line item for technology development. The bill also cuts NASA's space operations budget by more than $600 million from the 2010 level, an expected reduction due to the planned retirement of the space shuttle. It also denies a boost in aeronautics funding requested by the White House last year.

NASA's science budget was increased more than $400 million from last year to approximately $4.95 billion.

[someone_else]

H.R. 1473 provides $3 billion for NASA's new exploration program, including $1.8 billion for the Space Launch System heavy-lift rocket and $1.2 billion for a crew capsule.

I wonder for how much years they have to spend money to finally develop a HLV at this pace. A decade?

Also, what was the rationale to not shut down Constellation completely until now?

develop a new heavy-lift rocket, multipurpose crew vehicle and commercial capability to transport our astronauts and their supplies on American-made and launched spacecraft

(laughing).... commercial capability.... for an HLV.... and let's also say random nationalist bullshit on top of that.