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RobertDyck

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Re: The SLS: too expensive for exploration?

So frustrating. In 1994, NASA approached the Russia company Energia about using their big rocket. At that time they quoted NASA it would cost between $60 million and $100 million US dollars to restore certain elements of infrastructure, plus a per-launch cost of $120 million including the Energia Upper Stage. On April 25, 2002, the roof of the vehicle assembly building collapsed, destroying the Buran space shuttle orbiter, and all remaining Energia stages. Google Maps satellite image shows the roof of one of the three high bays has been replaced, the one used to stage modules for ISS. The two bays used for Energia/Buran are still open to the sky. Google Maps used to give a date for the image, but now every image just has a copyright notice with the current year. Lift capacity of Energia is about 2/3 that of SLS, but my point is cost. How the hell can SLS cost this much? Yea, I know, the price quoted is not for development of Energia or constructing infrastructure, just restoring it to flight. But still.

The really frustrating thing is what Russia is doing to Ukraine right now. We can't use any Russia stuff while that is going on.

SpaceNut

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Re: The SLS: too expensive for exploration?

The real question on the SLS price per launch is for after the design work is all done and we get to amatize the developement costs against the steady state products of more that a single unit a year use, will its quoted costs drop or is it just inflate contracting that makes it so high....
So the only thing that we want of SLS is the heavy lift capacity less the ever expanding price tag.

RobertDyck

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Re: The SLS: too expensive for exploration?

For steady human exploration of Mars: one mission every 26 months. That is one per conjunction of Earth & Mars. Two SLS launches per mission. I could describe Mars Direct, or my mission plan. Either requires 2 launches per mission.

GW Johnson

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Re: The SLS: too expensive for exploration?

I don't know the escape trajectory payloads for the big version of SLS and for Falcon-Heavy.  But the LEO payload ratio ought to be similar.  SLS is around 100 to 130 tons,  Falcon-Heavy 53 tons,  to LEO.  That's about 2 or 2.5:1. 

If you just price the direct launch costs for your mission's tonnage on a unit payload mass, assuming you are flying full,  Falcon-Heavy is unit priced around $1000/lb.  What that says is SLS unit costs should be no more $2500/lb to launch the same tonnage for an equal total launch price,  same total tonnage. 

I don't believe anything published about SLS says the cost will ever be that low,  in any of the configurations.  And NASA's history has been to underestimate costs.  Some of things I saw suggested $4000+/lb at about 100 tons to LEO.  So why fly that launcher unless there is some really, really-compelling reason to launch individual payload units that massive? 

That being said,  why not break the Mars mission payloads into smaller modules that Falcon Heavy could fling,  and do it that way for less launch cost money?  2 SLS launches would equate in tonnage flung to 4 or 5 Falcon-Heavy launches,  depending upon whether the flung tonnage ratio was 2 or 2.5. 

The key to actually achieving the savings with the smaller but way-cheaper commercial launcher is being able to break your payload items into the 53 ton increments.  (That's a different technical design constraint,  which may lead to a different design approach.) 

Do that,  and your direct launch costs will go down.  But it does require that you think modular during the design processes,  and it may mean orbital assembly instead of a direct shot to Mars.  Hard to say,  until one is actually doing a real design. 

Why is the smaller commercial launcher so much more cost-efficient than NASA's Congress-mandated SLS?  Because the supporting infrastructure (mostly the human headcount) is about 10 times smaller,  and (also very important) the development schedule was a lot shorter.  That comes from having to be competitive in the commercial launch business. 

All mission designs are inevitably "sub-optimal",  being entirely constraint-driven.  That's just life.  Inappropriate constraints lead to untenable results,  though.  That's also life. 

I recommend we take off the constraint of political pork driving mission architectures and hardware selections,  and just look at what you can do with what you already have in the way of launch rockets,  within the lower cost constraint that commercial cost efficiency allows.  I think the results will pleasantly surprise anyone who actually looks.

When the launch business needs a 100+ ton launcher,  the participants in that business will come up with them.  That's future,  and probably 20 years out.  Why let that delay going to Mars?  We're flying up to 20 tons to LEO right now at $2500/lb,  and soon up to 53 tons at costs as low as $1000/lb to LEO. 

We built ISS out of items in the 10-15 ton class,  and mostly at $30,000+/lb to LEO in the shuttle.  We don't have to suffer costs like that anymore.  Why should we take a step back toward a more expensive launcher?  Just because it flings more tons?  We don't have to do that. 

So far,  I have NOT seen the really,  really-compelling need to only fling 100+ (to LEO) ton items (or whatever the numbers are for a direct trajectory). 

GW

---

GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

SpaceNut

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Re: The SLS: too expensive for exploration?

Advanced Boosters progress towards a solid future for SLS

The previously delayed QM-1 test firing now remains on track for March 11, still well within the critical path schedule for the debut launch of SLS in 2018.

The five segment booster – a direct descendant of the four segment motor – is expected to fly into at least the mid-2020s, with both the 70 mT Block 1 and the 105 mT Block 1B variant – with the latter expected to become the SLS workhorse.

As such, Orbital ATK’s Advanced Booster proposal is the clear favorite to take over from the current five segment motor.

These new super boosters – nicknamed “The Dark Knights” – would be a large evolution on the current motors, both internally and externally.

Moving away from the traditional steel casings, a switch to composite materials, fabricated from low cost, high strength fibers, provide a documented payload capability improvement of 4,128lbm.

With the move back to four segments, the simplified stage assemblies comparison cites this would become part of a saving of 480 man hours – resulting in a 50 percent reduction in the man hours compared to that required for the five segment motor.

ATK claimed in their documentation that the booster would be 40 percent less expensive and 24 percent more reliable than the current SLS booster.

In 2012, Pratt & Whitney Rocketdyne (PWR) – now Aerojet Rockeydyne – went straight into “beast mode” with a proposal to utilize F-1 powerhouses from the heritage of the Saturn era, resulting two liquid boosters that could enable SLS to power 150 mT to orbit.

Alabama company Dynetics was brought on board to mature the design that saw two modernized F-1 engines – known as the F-1B – paired on each booster.

SpaceNut

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Re: The SLS: too expensive for exploration?

World’s Most Powerful Solid Booster Set for Space Launch System Test Firing on March 11

This is the qualification motor, QM-1, a 5-segment booster just waiting to produce 3.6 million lbs of maximum thrust.

The QM-1 booster is being conditioned to 90 degrees and the static fire test will qualify the booster design for high temperature launch conditions. It sits horizontally in the test stand and measures 154 feet in length and 12 feet in diameter and weighs 801 tons.

The static fire test will collect data on 103 design objectives as measured through more than 534 instrumentation channels on the booster it is firing.

The second booster test in March 2016 will be conducted at lower temperature to qualify the lower end of the launch conditions at 40 degrees F.

The maiden test flight of the SLS is targeted for no later than November 2018 and will be configured in its initial 70-metric-ton (77-ton) version with a liftoff thrust of 8.4 million pounds. It will boost an unmanned Orion on an approximately three week long test flight beyond the Moon and back.

NASA plans to gradually upgrade the SLS to achieve an unprecedented lift capability of 130 metric tons (143 tons), enabling the more distant missions even farther into our solar system.

2 x 3.6 million lbs = 7.2 million leaving the main engines to produce 1.2 million with 4 x rs25 (SSME) just to move to orbit and towards the moon when the old 4 segment with 3 SSME engines could loft the 100 ton orbiter to orbit....

SpaceNut

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Re: The SLS: too expensive for exploration?

The 4th test firing was done today and appears to be successful out of 5 tests to be done to qualify the motor for use.
QM-1 test fire turns Utah sand to glass in lead up to first flight of SLS

Development Motor 1: Conducted to determine the baseline processes involved with the up-rated version of the booster at ambient temperatures (approximately 80 °F; 27 °C). This test was carried out on Sept. 10, 2009.

Development Motor 2: A little more than a month after DM-1, NASA and ATK tested the booster under far colder conditions, some 42 °F (5.5 °C). This version of the SRB had a thicker nozzle, a full PBI aft dome, AEC ply angle change, triple wrap cowl and improved insulation.

Development Motor 3: This test continued the theme of studying the booster’s reaction to various temperatures with higher temps and loads. The DM-3 booster checked out the configuration at 92 °F (33 °C) and used an SCP cowl, interim internal insulation configuration. The nose cap saw a change in the type of material used and the booster also had the full PBI aft dome and nozzle plug installed.

With the DM series of tests complete, NASA and Orbital ATK are now testing what will essentially be the SRB used on SLS. Both QM-1 and the next test, QM-2, will use identical boosters – only the temperatures at which they are tested will be altered. QM-1 was a hot test with the rocket motor tested at 90 °F (32 °C). QM-2, by comparison, will be tested cold – at temperatures of approximately 40 °F (4 °C).

“We don’t expect that these boosters will see temps one way or the other (hot or cold) greater than what we test them under,” said Brian Duffy, a four-time space shuttle veteran who is currently employed with Orbital ATK.

SpaceNut

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Re: The SLS: too expensive for exploration?

NASA’s Office of Inspector General warned that Ground Systems Development and Operations, or GSDO in a
Report: NASA May Be Hard-Pressed to Launch SLS by November 2018

Despite its concerns, the OIG is not writing off a launch date of November 2018 just yet.

Ground systems are a critical piece of the SLS-Orion infrastructure. All three elements are tightly integrated, with ground systems requiring significant input from the rocket and capsule designs.

This is not the case for SLS, Orion and GSDO—each program is managed independently, with an emphasis placed on cross-program coordination. The OIG believes this approach is inefficient and could lead to scheduling delays.

"Since June 2012, NASA has identified 462 interdependencies between the GSDO, SLS, and Orion Programs," the report said. "To date, NASA has resolved 295 items (63.8 percent) with 167 remaining."

In a statement to The Planetary Society, NASA said the current approach is actually similar to the Apollo program:

SpaceNut

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Re: The SLS: too expensive for exploration?

NASA adding to list of CubeSats flying on first SLS mission

With room for 11 small shoebox-sized CubeSats on the first test flight of NASA’s behemoth Space Launch System, agency officials have turned to scientists, industry and students to fill the slots in time for launch in 2018.

NASA has selected three CubeSats developed by internal government teams for flight on the SLS demonstration launch, and officials announced last week two more top candidates that could be manifested on the mission.

The Space Launch System is scheduled to lift off from NASA’s Kennedy Space Center in Florida in 2018, lofting an unmanned Orion capsule on a flight around the moon. Astronauts will strap inside the Orion spacecraft on the second SLS flight, which is set for 2021.

The Orion crew capsule’s mission will last about three weeks before returning to Earth for a splashdown in the Pacific Ocean.

After separation from the SLS upper stage, one of the CubeSats — Lunar Flashlight — will maneuver into polar orbit less than 20 miles above the moon by deploying a solar sail, an ultra-thin membrane designed to harness pressure from sunlight for propulsion. Using the reflective 860-square-foot solar sail as a makeshift mirror, Lunar Flashlight will shine sunlight into permanently dark craters at the moon’s south pole, where temperatures hover just above absolute zero, cold enough to lock deposits of water ice over billions of years.

Like Lunar Flashlight, the NEA Scout CubeSat will unfurl a large solar sail and target an asteroid less than 50 meters — 164 feet — in diameter. The probe will fly within a kilometer — about 3,000 feet — of its target at low speed, allowing an on-board camera to collect high-resolution imagery resolving features on the object as small as a flying disc.

Tom Kalbfus

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Re: The SLS: too expensive for exploration?

I wonder where NASA gets the name "cubesats"? don't they have satellites that come in the shape of other regular solids, such as the tetrahedron the octahedron, the decahedron or the dodecahedron?

SpaceNut

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Re: The SLS: too expensive for exploration?

Like the title of the topic suggests, so whats up with Nasa making contracts that are this bloated, its just wrong.

NASA finalizes $2.8 billion Boeing contract for SLS rocket stage

The first SLS rocket is scheduled for its maiden flight, carrying an uncrewed Orion capsule, in 2017. The rocket's second flight -- the first carrying astronauts -- is planned for 2021.

Thats all we get is just 2 ....for the money...

Article goes onto state what Boeing has been paid..

A spokeswoman at NASA's Marshall Spaceflight Center in Huntsville, Ala., where the SLS program is managed, said NASA paid Boeing $1.656 billion between 2007, when work on the Ares rocket began, and today. Of that total, $606.5 million went to Ares-specific work. Since December 2011, when the undefinitized SLS contracts were awarded, NASA has paid Boeing $1.05 billion.

The new $2.8 billion contract, signed July 1, extends through 2021. It includes about $700 million that has already been spent on tooling and other SLS items at NASA's Michoud Assembly Facility in New Orleans, where the booster will be built and put together before transport to the Kennedy Space Center for launch.

SpaceNut

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Re: The SLS: too expensive for exploration?

NASA confirms EUS for SLS Block IB design and EM-2 flight

In the U.S. 111th Congress’s “National Aeronautics and Space Administration Authorization Act of 2010,” a specific provision was enacted into law that required NASA to “achieve full operational capability for the transportation vehicle developed pursuant to this subsection by not later than December 31, 2016.”

NASA told to resolve SLS Upper Stage dilemma

NASA officials have admitted the interim Upper Stage for the Space Launch System is at the top of their “worry list”, as the Agency’s key advisory group insists NASA should make a decision about bringing the more powerful Exploration Upper Stage (EUS) online sooner. The Aerospace Safety Advisory Panel (ASAP) fears NASA is at risk of wasting $150m on an Upper Stage they intend to “toss away”.

The reason for such an advanced launch date was largely related to the caveat of Orion providing a “back up” role to the Commercial Crew Program (CCP) – in the event of a serious setback for (both of) the commercial providers.

Such a requirement was never taken too seriously by NASA, not least because such a scenario would involve the overpowered 70mT capable Block 1 SLS (as such launching with “tons of ballast”) lofting a Beyond Earth Orbit (BEO) designed Orion (to LEO), with a crew on its debut mission (safety rules call for a uncrewed debut), at a cost that would probably solve any of the Commercial Crew Program woes that initiated such a backup requirement.

The current plan calls for this stage to be used on Exploration Mission -1 (EM-1) and Exploration Mission -2 (EM-2), prior to moving to the EUS – also to be built by Boeing – that will become the workhorse for SLS.

However, using the ICPS on a crewed mission will require it to be human rated. It is likely NASA will also need to fly the EUS on an unmanned mission to validate the new stage ahead of human missions.

This has been presenting NASA with a headache for some time, although it took the recent ASAP meeting to finally confirm those concerns to the public.

The ASAP was told it will cost “at least $150 million” to human-rate the ICPS engine, something the panel believe “will be wasted because this design will be ‘tossed’ in the near future.”

So by trying to shortcut developement with using what works for the interum stage it however is now called a waste of money and not meeting the total rocket that congress had wanted....

SpaceNut

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Re: The SLS: too expensive for exploration?

kbd512 Nasa does have a mandate and on SLS

Competing heavy lift

By Jeff Foust on 2011 June 5 at 12:35 pm ET

As first reported by Space News last Thursday, California’s two senators have asked NASA to hold an open competition for the development of the Space Launch System (SLS),

House Committee Approves Bill Requiring Congressional Approval Before Terminating JWST, ISS, SLS or Orion

Posted: 11-Dec-2013

The bill, H.R. 3625, initially had two major thrusts:  to require the Administration to obtain congressional approval before terminating SLS, Orion or the ISS, and to prohibit contractors on those programs from setting aside appropriated funds to cover costs the government would have to pay in the event it did terminate any of those programs for the convenience of the government -- called termination liability costs. 

The House Science, Space and Technology Committee approved today a bill that changes how NASA would manage termination of four of its major programs if such a decision were made.
Shelby vows to protect the SLS

By Jeff Foust on 2013 January 30 at 7:57 am ET
Responding to what is at least a somewhat manufactured controversy, a key senator said Tuesday that he will continue to support NASA’s Space Launch System (SLS) heavy-lift launch vehicle. Sen. Richard Shelby (R-AL) told the Huntsville Times that he will “continue to fight hard to ensure that taxpayer dollars are invested wisely in SLS so that we maintain our nation’s leadership role in human spaceflight,”

More False Memories About the Origin (and Cost) of SLS
"The SLS vehicle design materialized from an extensive, unbiased set of NASA technical studies which compared all possible scenarios, with a focus on efficiency and budget constraints."

Mike Griffin says "And, contrary to some suggestions, SLS launches will cost no more than existing commercial U.S. systems - which are currently advertised at about $4.5 million per ton of payload."

RobertDyck

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Re: The SLS: too expensive for exploration?

In 2012, Pratt & Whitney Rocketdyne (PWR) – now Aerojet Rockeydyne – went straight into “beast mode” with a proposal to utilize F-1 powerhouses from the heritage of the Saturn era, resulting two liquid boosters that could enable SLS to power 150 mT to orbit.

Alabama company Dynetics was brought on board to mature the design that saw two modernized F-1 engines – known as the F-1B – paired on each booster.

The article that Spacenut linked cites a November, 2012, article about that booster:
Dynetics and PWR aiming to liquidize SLS booster competition with F-1 power
How much mass could SLS lift to LEO if SRBs were replaced with this liquid booster, and instead of SLS block 2, just use the 4-SSME core stage and Exploration Upper Stage (EUS) of SLS block 1B? How much mass to ISS? How much to direct throw to TMI?

SpaceNut

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Re: The SLS: too expensive for exploration?

Post image indicates 150mt

If Irc the F-1 is an AR-1 by the company developing it...as a Updated F-1 Could Replace RD-180 Rocket Engine

If the Air Force decides to move forward with a similar risk-reduction and technology development program as NASA, a prototype of the AR-1 could be ready in 2–1/2 years and “get to a full-up operational engine by 2019,” Cook said.

Aerojet Rocketdyne Targets $25 Million Per Pair For AR-1 Engines

Including legacy systems and various risk-reduction projects, Aerojet Rocketdyne has spent roughly $300 million working on technologies that will feed into the AR-1, Seymour said during a June 3 roundtable with Aviation Week editors. The effort to build a new, 500,000-lb. thrust liquid oxygen/kerosene propulsion system would take about four years from contract award and cost roughly $800 million to $1 billion.

The booster also could be modeled after the Space X Falcon design and make them recoverable which should drive the cost down.

RobertDyck

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Re: The SLS: too expensive for exploration?

The 2012 article talks about replacing advanced SRBs with their booster, but otherwise still block 2. Notice the image of the rear shows the core stage with a 5th SSME. That means 150t to LEO for block 2 with 5-SSME core stage, and full size upper stage with a pair of J-2X engines.

According to Wikipedia, AR-1 is a proposed engine to replace RD-180 for Atlas V. It produces 500,000 lbf thrust. F-1 from the Saturn V first stage produced 1,522,000 lbf each. The updated F-1A produced 1,800,000 lbf thrust. F-1A was developed in the 1960s, intended as an upgrade to Saturn V for whatever followed Apollo. But Saturn V was shutdown with Apollo. F-1B is updated to use modern manufacturing techniques (3D printing, etc), and retain the performance of F-1A. News article info-graphic says 1,805,000 lbf thrust.
Wikipedia F-1B

My question is what would we get if SLS block 2 is never built? What if we never get the 5-engine core stage, or upper stage with J-2X? What would we get with just SLS block 1B, but replace 5-segment SRBs with a pair of these?

Last edited by RobertDyck (2015-07-06 12:10:57)

RobertDyck

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Re: The SLS: too expensive for exploration?

Interesting. Upgraded SRB after Challenger was called "Reusable Solid Rocket Motor" or RSRM. Each had 2,800,000 lbf thrust. SLS 5-segment boosters produce 3,600,000 lbf thrust. Each liquid booster with a pair of F-1B engines would produce 3,610,000 lbf thrust. But the article claims NASA is concerned the liquid boosters would produce too much acceleration. What? That's just 0.278% more thrust. Why would that be a concern? Sounds like more sales and marketing hype, to support one contractor vs another.

Last edited by RobertDyck (2015-07-05 22:09:17)

SpaceNut

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Re: The SLS: too expensive for exploration?

The liquid booster can be throttled back so as to produce an equal force as compared to the new 5 segment SRB units so its unwarranted concern. Then once we reach MaxQ we throttle back up and achieve a higher orbital plane which is dependant on the payload mass.
srb thrust vs burn time https://en.wikipedia.org/wiki/File:Srbthrust2.svg

The SRB 5 segment producing approximately 3.6 million pounds of thrust, or 22 million horsepower, and burning for just over two minutes is estimated to provide a capability of 130mt to orbit for the block 2 design.

The fully evolved SLS, their proposed booster delivers 150mt, “providing a 20mt (15 percent) margin but the liquid boosters are missing all the data to be able to compare them to the solid boostes....

https://en.wikipedia.org/wiki/Ares_(rocket_family) all the favors you could want...

Something else that I had forgotten was that Nasa spent money on the rs68 to make it possible for its useage in the SDV but with the cancellation of the ULA Delta IV there is another engine that USA will not be making any more...

RobertDyck

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Re: The SLS: too expensive for exploration?

One news article asked for man rating Delta IV Heavy. That's so it could launch Orion to ISS. But I cringed when I read that. Ares V was originally going to use 5 SSMEs. Some NASA engine guys wanted to design a new engine based on SSME, but 50% more thrust. Manufacturer of the RS68 argued their engine already produces 50% more thrust than SSME, and is cost optimized for an expendible launch vehicle. So NASA management was convinced to switch to RS68 as-is, no modification. Then the argument to man rate. Then the engine guys chose to add on all the features of SSME missing from RS68, turning it into the SSME with 50% more thrust that they wanted to build. RS68 had lower Isp, but lower engine cost. Additional propellant and tank cost less than the cost saving, so it was cost optimized for the first stage of an expendable launch vehicle. This redesign to turn it into the new engine that the NASA engine guys wanted, just undid management's decision. So when the news article talked about man rating Delta IV Heavy and its RS68 engine, I was afraid the same problem would come back.

I could argue for SLS block 2 with all 5 main engines. I could also argue for the full size upper stage with J-2X engines. Both launch vehicles developed under EELV, Atlas V and Delta IV, were designed to be flexible. One option for Atlas V was either one or two engines for the upper stage. Either 2 engines for heavy lift to LEO, or one engine for Earth departure such as the Moon or Mars. You could do the same with SLS: one or two J-2X engines. That would be sweet!

I'm worried we won't get block 2 at all. That would make SLS useless for Mars.

Thank you for the link to SRB thrust profile. Very interesting. The liquid boosters can be throttled within that range.

SpaceNut

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Re: The SLS: too expensive for exploration?

I think I found why the j-2x was not gone forward with in the SLS as well in this article http://www.nasaspaceflight.com/2011/11/ … test-fire/

It appears that the rehashed j-2 is apt to have manufacturing & test issues...

I think the RS68-B was the man rated engine but then again they also redid the brain for the ssme as well.

Agreed launch capability on the order of 100mt plus needs to be made and a reasonable launch cost even if only fore large cargo....

RobertDyck

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Re: The SLS: too expensive for exploration?

The article says the resolved the issues, and completed tests. That's what testing is for. They identified issues, and resolved them without catastrophic engine failure.

There were further tests in 2013 & 2014, on the A-1 test stand. Including full gimbal tests. I found a June 2014 article that said no further tests.

And this test was on the A-2 test stand, in open air at surface level air pressure. The engine is intended for operation at high altitude, where air pressure is extremely low to zero. The A-3 test stand was built to test exactly this engine, in exactly those conditions. I want to see a similar set of tests, and debugging/repair, done on A-3. That's the test stand that the Washington Post called "monument to bureaucracy". Using the test stand for exactly what it was built for would demonstrate it isn't. One would think politicians would want that.

You pointed to the info-graphic to answer my question. That shows SLS Block 1A with lift capacity of 103 - 120mT. The article states...

The SLS Block 1A configuration with the proposed Advanced Booster provides payload capability from 103 mT (F-1 derated to 85 percent) to 120 mT (100 percent F-1 power level).”

That doesn't answer what performance it would have with the Exploration Upper Stage (EUS) with RL10 engines. Wikipedia cites a 2013 study by NASA and Boeing. They found Block 1A without an upper stage could lift 70t to LEO, or with ICPS 20.1t to TMI. Block 1B with 5-segment SRBs and EUS could lift 105.2t to LEO, or 31.6t to TMI. Dynetics says Block 1A with ICPS and their liquid boosters could lift 120t to LEO. So with liquid boosters and EUS it should deliver more. All masses in metric tonnes.

SpaceNut

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Re: The SLS: too expensive for exploration?

SAearched a bit to find out why the RL10 selection and its seems that SLS prepares for PDR – Evolution eyes Dual-Use Upper Stage

June 1, 2013 by Chris Bergin

Where the key was time to launch the SLS to meet Congress timeline and cost to finish developing the ...
The article indicates that the concern is height of the stage and with the diameter it means controling the amount of fuel in the stage which interns is the stage height.

Documentation from 2012 also pointed towards the evaluations into using the RL-10 driven stage, showing the SLS Block 1B, using Five Segment Boosters, resulting in an up-mass capability of 118mT to Low Earth Orbit (LEO) and 43mT to Beyond Earth Orbit (BEO).

The information also shows the SLS Block 2 – again with the 8.4 meter diameter 4xRL-10 stage – with Advanced Boosters, allowing for an up-mass capability of 155mT to LEO and 61mT to BEO.

NASA's huge rocket needs engine with flight heritage
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: February 27, 2012

NASA must find and purchase a cost-effective, proven cryogenic propulsion system for the first two flights of the agency's heavy-lift Space Launch System because the space agency is slowing development of behemoth rocket's Apollo-era upper stage engine to fit under a flat budget profile.
NASA's requirements state the interim upper stage must be hydrogen-fueled, rated for human launches, and capable of at least three ignitions with power the change the 26.5-ton Orion spacecraft's velocity by more than 6,800 mph.

Agency managers also set mass and length requirements for the rocket stage. The upper stage system must be delivered to the Kennedy Space Center by the end of 2016 to support the first SLS mission.

May said the critical path to support the heavy-lift rocket's 2017 launch date is in the cryogenic core first stage, a 27.5-foot-diameter rocket, the same size of the space shuttle's external fuel tank.

Next Steps for SLS: Europe’s Vinci is a contender for Exploration Upper-Stage Engine

By David Todd on 7 November, 2014 in NASA, SLS

Here is a table of all the engine to block information.

RobertDyck

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Re: The SLS: too expensive for exploration?

Perfect! That's exactly what I asked for. Thanks.

So what they're calling Block 2B has only 4 engines on the core stage, and the EUS upper stage with 4 RL10 engines. But the improvement over Block 1B is replacing 5-segment SRBs with advanced liquid boosters. With 2 F-1B engines each, that can throw 44.0 metric tonnes to TMI.

It looks like we won't get the 5-engine core stage. Or the upper stage with J-2X engines. So replacing SRBs with liquid boosters is the solution we could hope for. Now do we get the F-1B engine, or 6 AR-1 engines per booster? With 2 boosters, that's 12 AR-1 engines plus 4 RD-25 engines for the core stage. That's sounding like the Soviet N1. Does my bias for updated Saturn V technology show?

"The Case For Mars", 1997 edition, paperback, page 4: The ERV is 45 metric tonnes at TMI, including aerobrake (ADEPT heat shield), and propellant for in-space course corrections. That book describes a 6 month transit for both ERV and hab, but I think we would use an 8.5 month transit like Curiosity for the ERV; and a 6 month "express" trajectory for crew, like Spirit or Opportunity. The point is Block 2B could be good enough.

Last edited by RobertDyck (2015-07-09 00:50:28)

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: The SLS: too expensive for exploration?

Have some more money contractors...
Orbital ATK agree deal for Orion LAS through to second SLS mission

Orbital ATK has signed a deal worth nearly $100m dollars to provide Orion’s Launch Abort System (LAS) through to the second mission for the Space Launch System (SLS). The deal also covers an Ascent Abort test (AA-2) – which will be conducted in-between the maiden flight of SLS in 2018 and the second flight in the early 2020s.

RobertDyck

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From: Winnipeg, Canada

Registered: 2002-08-20

Posts: 7,924

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Re: The SLS: too expensive for exploration?

I'm concerned over how much time SLS is taking. And contractors are charging NASA for all that time. But if asked to work more quickly, the contractor claims they need even more money.
Between 1960 and 1962, the Marshall Space Flight Center designed a series of Saturn rockets that could be used for various Earth orbit or lunar missions.
January 10, 1962: NASA announced plans to build the Saturn C-5.
November 9, 1967: Apollo 4. First unmanned, all-up test flight; complete success.
April 4, 1968: Apollo 6. Second unmanned test flight
December 21, 1968: Apollo 8. First manned flight. First translunar injection of CSM.
Apollo 8 was intended to be an unmanned test. To test TLI, and the CSM ability to fly round the Moon and return to Earth safely. Astronauts rode on it because fears Russia would do it first. So...
March 3, 1969: Apollo 9. Manned low Earth orbit test of CSM with LM

Now compare with SLS. Work actually started with Ares V. Constellation formally started with the NASA Authorization Act of 2005, signed December 30, 2005. Cancelled October 11, 2010. NASA Authorization Act of 2010 was signed on October 11, 2010. SLS was detailed in a joint Senate-NASA presentation in September 2011. The first unmanned test launch of SLS Block 1 is scheduled for November 2018, but NASA is worried they won't be able to meet that date. If you don't include Ares V, that's 8 years and a month from authorization to first unmanned test launch. If you count it that way then Saturn V started January 10, 1962; first unmanned test launch November 9, 1967. And Saturn V was developed from scratch, SLS is building on Saturn and Shuttle heritage.

Saturn V took 5 years and 10 months. SLS will take 7 years and 2 months from presentation to launch. Including earlier studies, Saturn V took 7 years. Including Ares I & V, SLS will take 12 years. And that's just for SLS Block 1. We don't have any time frame for SLS Bloxk 2 or 2B. Any excuses?

Saturn I could lift 9.07 metric tonnes to LEO. The order authorizing it was signed 15 August 1958; first test launch was October 27, 1961. It was upgraded by replacing the upper stage with the third stage of a Saturn V. It could lift 21 tonnes to LEO; first test launch February 26, 1966. How do we count that? Order to Saturn 1 or 1B launch? That's 3 years and 2 months to first launch.

Yea, the SIVB stage had a couple differences: different instrument unit (electronics), and one igniter instead of two so only one engine start. Otherwise the same stage. Can't really count Saturn 1B from authorization to first launch, because it used a Saturn V stage.

Still. Why is SLS taking so long, and why cost so much?