Author Topic: Fly Me to the Moon on an SLS Block II  (Read 9930 times)

Offline MP99

Re: Fly Me to the Moon on an SLS Block II
« Reply #20 on: 08/01/2015 09:52 AM »
Quote
So why develop block II if not needed for Lunar?

That's what Congress wants. If the aim is Block II, then that is what should be developed. Once developed, it can be flown in a Block IB configuration if desired.

Block 1B would mean going back to using RSRMVs, which I think is unlikely.

I think the config with EUS and advanced boosters, but without LUS (which I assume you meant) would be better called Block 2B.

Cheers, Martin

Offline Brovane

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Re: Fly Me to the Moon on an SLS Block II
« Reply #21 on: 09/07/2015 09:34 PM »
@RocketmanUS

While I somewhat agree that NASA should try to avoid "building" rockets, what commercial options do they have for the payload mass they're talking about? Should they wait for SpaceX's BFR? What happens if it doesn't come to fruition, and if it does, what kind of political fallout would ensue in the event that it's a failure? Besides that, they have no other options.

While I do think the SLS is unwarranted for the time being as it doesn't even have any definitive missions, nevermind the extreme cost, I do understand why NASA wants to design a rocket to their spec (and of course you have some in congress demanding it). Sure, they could pour that money in expediting BFR development, but there would be [somewhat understandable] cries coming from all corners of aerospace and government regarding such subsidies of one company, and I doubt SpaceX would want to share development with anyone else on that project.

Why do you assume that Commercial option means that NASA's budget doesn't pay for any of the hardware development?   With the COTS development contracts we have seen both Private and Public money being put in to develop the hardware that NASA needs.  You could save development money by simply moving away from Cost-Plus contracts to Fixed Cost contracts still using FAR regulations.  We don't need a cost-plus contract to develop a HLV, there isn't that many unknown-unknowns that a contractor cannot adequately plan for the development risks. 
"Look at that! If anybody ever said, "you'll be sitting in a spacecraft naked with a 134-pound backpack on your knees charging it", I'd have said "Aw, get serious". - John Young - Apollo-16

Offline Steven Pietrobon

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Re: Fly Me to the Moon on an SLS Block II
« Reply #22 on: 04/27/2017 06:40 AM »
I submitted my paper to the IAC congress being held in Adelaide this year. I got a reply today saying my paper was accepted!
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline carmelo

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Re: Fly Me to the Moon on an SLS Block II
« Reply #23 on: 04/27/2017 06:42 PM »
Thanks Steven!
You have answered to this my old question:

http://forum.nasaspaceflight.com/index.php?topic=42711.0

Yes,we can.

Offline Patchouli

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Re: Fly Me to the Moon on an SLS Block II
« Reply #24 on: 04/30/2017 04:35 PM »
I wonder how high risk would refueling the EUS be as that could greatly increase the TLI payload?

Another option if it's fully operational by then launch part of the hardware on a Falcon Heavy and do all staging of the mission in LEO vs L1.

I'm assuming that FH actually can lift 53 tons as that would be enough for an Altair class lander plus a few tons for a payload interface.
« Last Edit: 04/30/2017 04:37 PM by Patchouli »

Offline TrevorMonty

Re: Fly Me to the Moon on an SLS Block II
« Reply #25 on: 05/01/2017 01:46 AM »


I wonder how high risk would refueling the EUS be as that could greatly increase the TLI payload?



If ULA's distributed lift proves successful then an upgraded EUS to support refuelling could be easy upgrade to SLS. Switching EUS to ULA flight proven (by then) IVF would be low risk upgrade with huge payload benefits.

Offline Steven Pietrobon

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Re: Fly Me to the Moon on an SLS Block II
« Reply #26 on: 07/21/2017 06:32 AM »
To celebrate the 48th anniversary of the first crewed landing on the Moon, here's the latest version of my paper. Updates are:

1) Changed the engine configuration of the LM. Now have a central fixed thrust and position engine in middle for ascent and abort (instead of two canted nozzles) and two variable thrust and position engines next to the ascent engine (instead of one engine).
2) The increased performance from the ascent engine (since it is no longer canted) allowed an increase of the boil off rate from 0.1% to 0.17% per day, with the cargo mass slightly decreasing from 535 to 509 kg.
3) Deleted the core engine configuration with five engines at the circumference and a central engine. Added a core engine configuration with two rows of three engines. This gives better spacing to the booster nozzles.
4) Deleted the six flight cost numbers. Added 29 flight cost numbers for SLS Block II and dual flight Block IB, which is the break even point where Block II becomes cheaper.
5) For Orion Block II, showed that this allows plane changes up to 12.1 with current service module. Cargo mass decreases from 3396 kg to 2296 kg.
« Last Edit: 07/21/2017 06:55 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Steven Pietrobon

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Re: Fly Me to the Moon on an SLS Block II
« Reply #27 on: 07/21/2017 06:40 AM »
Michel Lamontagne from Canada has been doing some fantastic work on providing artwork of the launch and landing sequence. Here's some preliminary artwork to whet your appetite.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline MATTBLAK

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Re: Fly Me to the Moon on an SLS Block II
« Reply #28 on: 07/21/2017 06:47 AM »
That's awesome! :) I admit that most of the math in the paper is beyond my relatively igorant edumacation ;) I was once going to have professional artwork for my old Mars Mission paper - but I had to use my crude temp drawings instead! This gives your publication some extra class...
« Last Edit: 07/21/2017 06:56 AM by MATTBLAK »
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Offline Propylox

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Re: Fly Me to the Moon on an SLS Block II
« Reply #29 on: 07/22/2017 01:56 AM »
Today is the 46th anniversary of Apollo 11 landing on the Moon.

"We examine how a 140 t to low Earth orbit (LEO) Block II configuration of the Space Launch System (SLS) can be used to perform a crewed Lunar landing in a single launch. ...
Nicely done. Your dedication and detail is as impressive as successfully crafting a direct-to-landing mission. Not the path I'd take, but much respect is deserved and given.
I was quite surprised by your drymass of 123.6mT for the six-engine core as it seems exceptionally high.
« Last Edit: 07/23/2017 03:01 AM by Propylox »

Offline MATTBLAK

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Re: Fly Me to the Moon on an SLS Block II
« Reply #30 on: 07/22/2017 05:22 AM »
I too would prefer a single-launch Lunar mission like 'the good old days'. But forgive me if I missed anything at some stage: have you ever crunched the numbers for a Lunar mission done with dual launches of an SLS Block 1B or similar? I know that would be an expensive mission; though it should allow for a much bigger LM for pretty long stay times on the surface. Also; should allow cargo-only LM versions in single launches of a Block 1B.
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Offline Propylox

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Re: Fly Me to the Moon on an SLS Block II
« Reply #31 on: 07/23/2017 12:53 AM »
Here's some preliminary artwork to whet your appetite.

That's a whole lot of rocket for an Apollo "flags and footprints" redux. Heck, SLS is a whole lot of rocket anyways and that's a problem IMO. I previously asked about your excessive core stage's drymass of 123.6mT and your J-2X US at 16.9mT seems quite light. I started with different assumptions, resulting in different masses for each and a different, though just as capable rocket. If you'd allow me ..........


The J-2X US would be fabricated on the existing 8.4m LOX jig, composed of a 22ft barrel similar to that used for the core tank. With a common bulkhead separating propellants it holds 422,680 lbs. As you mentioned, the final propellant load may be a bit less depending on mission. Utilizing commonality with the core for manufacturing purposes, cost reduction and it's location atop the RSRM crossbeam;

It has a drymass of 20,440kg with 2x J-2x -or- 18,350kg with a single J-2X flanked by 2x RL10s
 -- Maximum capabilities BLEO is achieved if all three ignite at staging with J-2X cutoff after 500s. If propellant flow is an issue, the RL10s would instead ignite after the 500s J-2X burn - essentially becoming a combined 2nd/3rd stage with BLEO max payload now equivalent to the 2x J-2X US

After completing the US, the existing 8.4m LOX jig would begin manufacturing another 22ft barrel with common bulkhead. The existing SLS uses five barrels and a gigantic thrust structure for its H2 tank. Instead, the LOX tank should be a sixth 22ft barrel where the current thrust structure wastes space.
The 2nd common bulkhead manufactured replaces the #5 barrel, including internal buttressing to handle additional loads. It's likely the #6 LOX barrel will need to be manufactured on the 8.4m LOX jig with reinforcing spars. The new abbreviated thrust structure and RS-68s now sit flush to the LOX tank.

This core has a drymass of 81,700kg with 3x RS-68 + interstage + a boattail to modify the thermal environment -or- 70,250kg without an US, only 2x RS-68 and a payload adapted in place of the interstage - directly atop the RSRM crossbeam. The corestage holds 1,907,626 lbs propellant with assumptions on final internal volume and a 6:1 O/F ratio.
-- The O/F ratio and internal volume will change during development as will specific mission load so the 1.9 million lbs is a current estimate. Whether in single or two-stage configuration, the core lifts off at 60% throttle for the first ~2min and throttles down to 60% at 3g when the tank nears empty. With significantly less drymass and propellant, the extra thrust isn't needed at liftoff and propellant better used after solid separation


* I calculate a 2x RS-68 single stage will place 65mT to 75mT into a 210km LEO, depending on constraints.
* The 3x RS-68 will place +130mT into LEO with a 2x J-2X US -or- 40mt to 45mT into a 311,425km x 185km expedition orbit, depending on constraints.

Funding wise; The existing EUS and Advanced Booster programs would be cancelled and resources allocated to common bulkhead development, production and re-engineering the business-end of the SHLV. You proposed and outlined the importance of J-2X (as have I and others), but I'd also cancel the RS-25 program, switch AR's production contract to J-2X and use RS-68s on the core with almost no modifications.
« Last Edit: 07/23/2017 01:01 AM by Propylox »

Offline Steven Pietrobon

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Re: Fly Me to the Moon on an SLS Block II
« Reply #32 on: 07/23/2017 03:36 AM »
I too would prefer a single-launch Lunar mission like 'the good old days'. But forgive me if I missed anything at some stage: have you ever crunched the numbers for a Lunar mission done with dual launches of an SLS Block 1B or similar? I know that would be an expensive mission; though it should allow for a much bigger LM for pretty long stay times on the surface. Also; should allow cargo-only LM versions in single launches of a Block 1B.

There's a rough analysis of the dual Block IB architecture in the paper. A single launch is 20% cheaper per mission, but has a higher development cost due to needing to develop a new core and large upper stage. At 29 missions, total cost (development and mission) single launch becomes cheaper overall.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Steven Pietrobon

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Re: Fly Me to the Moon on an SLS Block II
« Reply #33 on: 07/23/2017 03:50 AM »
That's a whole lot of rocket for an Apollo "flags and footprints" redux. Heck, SLS is a whole lot of rocket anyways and that's a problem IMO. I previously asked about your excessive core stage's drymass of 123.6mT and your J-2X US at 16.9mT seems quite light. I started with different assumptions, resulting in different masses for each and a different, though just as capable rocket. If you'd allow me ..........

How I derived these masses is described in the paper. The Block I core dry mass is 100,062 kg, so I believe my value is in the right ball park for a six engine core. I derived my LUS mass from the Saturn V S-II, which has a 35,402 kg dry mass and 452,352 propellant mass.

Quote
Funding wise; The existing EUS and Advanced Booster programs would be cancelled and resources allocated to common bulkhead development, production and re-engineering the business-end of the SHLV. You proposed and outlined the importance of J-2X (as have I and others), but I'd also cancel the RS-25 program, switch AR's production contract to J-2X and use RS-68s on the core with almost no modifications.

I did not investigate using RS-68 since that would need to be redesigned so that the ablative nozzle (which won't survive the base heating conditions) is replaced with a regenerative nozzle, practically making it a new engine. That kills any saving from using a "cheaper" engine. This is the same mistake Griffin made when he replaced RS-25 with RS-68 on Ares-V.
« Last Edit: 07/23/2017 03:52 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline MATTBLAK

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Re: Fly Me to the Moon on an SLS Block II
« Reply #34 on: 07/23/2017 11:42 AM »
Yes. I'm afraid that RS-68 is just not going to get used in basically any context with the SLS. And if NASA was ever going to do a redesign of the Corestage I'd certainly hope it would be to incorporate 5 or 6 RS-25E's.
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Offline Propylox

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Re: Fly Me to the Moon on an SLS Block II
« Reply #35 on: Today at 02:16 AM »
I did not investigate using RS-68 since that would need to be redesigned so that the ablative nozzle (which won't survive the base heating conditions) is replaced with a regenerative nozzle, practically making it a new engine.
Not the place to debate that ...
... but I'd think someone who could develop and write such a proposal would also know better. Carry on  :-X
« Last Edit: Today at 02:17 AM by Propylox »

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