Author Topic: Both Crawler Transporters grounded – Crawlerway testing for HLV capability  (Read 14462 times)

Online Chris Bergin

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Offline Harold KSC

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Good article Chris, very fair, as I know what you could have reported. Very responsible.

Offline DLR

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Hmmm .... the reliance on the VAB and those heavy crawlers is another point why the Shuttle infrastructure is so inefficient.


Horizontal integration is better to support faster launch rates. Proof: Number of successive Soyuz launches in the 1980s.

Online TrueBlueWitt

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Are upgraded crawlers/crawlerway really required for SDHLV if they stick with 4-seg SSRM?  From what I remembered J-130 would weigh less going out to the pad and even J-246 would be in similar range to Shuttle stack.

Offline kraisee

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I don't want to hijack this thread, but I will briefly answer your question as long as all DIRECT-specific followups are please redirected to the DIRECT Thread.

Jupiter-130/246 stacked on a modified MLP with no umbilical connections, requiring all umbilicals to be integrated at the Pad would mass the same as Shuttle during rollout.

Jupiter-130/246 stacked on a modified MLP with an Atlas-V-style Minimal Umbilical Tower (DIRECT's recommended approach, see attached) would still allow all of the electrical and plumbing umbilicals to be integrated in the VAB prior to rollout (the most critical aspect of clean pad benefits), but a Fixed Service Structure located at the Pads would handle all of the servicing work, and therefore allow the mass of the MLP to remain within current usable limits of the existing Crawlers & Crawlerway.

Jupiter-130/246 stacked on a new ML with a full-size 750 ton Apollo/Ares-I style LUT (service and umbilicals combined) will exceed the Crawler's capabilities.


Heavy (5-seg) and Heavy Stretched (5-seg and ~35% increased Core capacity) variants both break the middle case and would require a more robust Crawler design, incurring significant extra costs and schedule impacts.

Ross.

PS -- Sorry for the old "linear" engine arrangement depicted in that image.   It hasn't been updated in quite a while.
« Last Edit: 08/13/2010 04:01 pm by kraisee »
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Online Chris Bergin

Not at all Ross, it's all relevant. How come Ares V was so much heavier?
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Online bobthemonkey

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U/S mass. Thin, semi pressure stabalised ACES with RL10 v a heavy, self supporting S-IVB esque upper stage (possibly with loiter ring) and J2-X.

Offline Dappa

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Nice article, I like those huge crawlers.

And the thought of an even bigger one would be even better.  8)

Offline DaveS

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U/S mass. Thin, semi pressure stabalised ACES with RL10 v a heavy, self supporting S-IVB esque upper stage (possibly with loiter ring) and J2-X.
Don't forget two additional SRM segments and a larger and heavier core to go along with those additional SRM segments.
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Online bobthemonkey

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Of course. I was thinking back to Ares V as it originally was, before it got big[ger] and fat[ter].

Offline robertross

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Heavy (5-seg) and Heavy Stretched (5-seg and ~35% increased Core capacity) variants both break the middle case and would require a more robust Crawler design, incurring significant extra costs and schedule impacts.

Let's see...if we follow the money trail, and politics, I'd give it more than a 50% chance of having a new crawler, crawlerway, ML...

(you taught us well...hehe)

I for one hope it doesn't come to that. But there certainly is a case to build a new crawler in the forseable future for a Mars variant launch vehicle, keeping one unit operational and the other as a donor vehicle.

Offline kraisee

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Not at all Ross, it's all relevant. How come Ares V was so much heavier?

At 157.4mT the 10m diameter Core Stage of Ares-V masses roughly twice as much as a standard ET-capacity Jupiter Core.

Additionally, each extra half-segment masses around 75mT and Ares-V had 5.5-seg boosters, not 4.0-seg.

The Upper Stage was not a very efficient ACES-style design.

The J-2X is a pretty heavy engine.

And the payload mass on top was also higher.

But the real back-breaker was that giant LUT, which masses 750mT without counting any of the pipework, electric systems or any of the other extra equipment.

The final result of all that, is that the Ares-V's complete rollout stack is about 75% higher than the mass of a Jupiter-246 rollout stack.

Ross.
« Last Edit: 08/14/2010 01:17 am by kraisee »
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Offline kraisee

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Let's see...if we follow the money trail, and politics, I'd give it more than a 50% chance of having a new crawler, crawlerway, ML...

(you taught us well...hehe)

I for one hope it doesn't come to that. But there certainly is a case to build a new crawler in the forseable future for a Mars variant launch vehicle, keeping one unit operational and the other as a donor vehicle.

That is my biggest fear too.

If they don't work hard to ensure that this becomes a cost-effective and sustainable system, I believe it will get canceled by the next administration, in a similar way to how Ares got canceled by this one.

But if this happens again in 4 years time, a lot of other companies will be much better positioned to take over the entire operation and I believe NASA would find itself permanently removed from the marketplace -- if they are not smart enough to get it right this time.

Ross.
« Last Edit: 08/14/2010 01:28 am by kraisee »
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Offline simcosmos

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Let's see...if we follow the money trail, and politics, I'd give it more than a 50% chance of having a new crawler, crawlerway, ML...

(you taught us well...hehe)

I for one hope it doesn't come to that. But there certainly is a case to build a new crawler in the forseable future for a Mars variant launch vehicle, keeping one unit operational and the other as a donor vehicle.

That is my biggest fear too.

If they don't work hard to ensure that this becomes a cost-effective and sustainable system, I believe it will get canceled by the next administration, in a similar way to how Ares got canceled by this one.

But if this happens again in 4 years time, a lot of other companies will be much better positioned to take over the entire operation and I believe NASA would find itself permanently removed from the marketplace -- if they are not smart enough to get it right this time.

Ross.

5 segment SRB: development / operational requirements and constraints

Adding to above quotes and previous posts and to the NSF article (and related articles), the VAB / crawler / crawlerway / launchpads impacts of assuming other big solid boosters than 4 segment SRB might not end there...

... Yes, the 5 seg. SRB allow for extra performance that could be used either for extra abort scenarios (on a more standard ET core / conservative payload case) and/or as an 'enabler' for heavier lift capabilities (depending of launch vehicle assumptions) but it also introduces extra concerns regarding things such as modifications to crawlerway, extra requirements for (the) eventual new crawlers, etc...

Another thing that might require a very attentive look is the 'Quantity-Distance' (QD) issue (number of segments on close proximity vs a 'bad day' scenario at the VAB, nearby facilities...): depending of flight rate, mission design and specific launch vehicle choices, more or less 'mitigations' might be required...

This to say that when looking at references such as, for example...

2002: Exploration Blueprint Data Book
http://hdl.handle.net/2060/20070031201
Section 4.3 - Exploration Architecture Analysis Vehicle Processing and Launch Operations Assessment, example: Quantity Distance (QD) Challenge, page 358 (354 of the pdf)
(there is extra written information on that section, see also page 366, etc)
 
2006: ESAS Report
http://www.nasa.gov/exploration/news/ESAS_report.html
(very brief notes about QD on chapters 6 and 7)


Note: there have been some SRB stacking considerations for AresI but the Mars DRA 5.0 might probably be the most recent (and with nicer pictures too) reference regarding a generic discussion of the Quantity-Distance (vs options to deal with it):


2009: Mars DRA 5.0 (addendum)
http://www.nasa.gov/pdf/373667main_NASA-SP-2009-566-ADD.pdf
(http://www.nasa.gov/exploration/library/esmd_documents.html)
Starting +/- on page 184 (page 204 of the pdf)...


... as was writing, when looking at such references, the adoption of 5 segment might lead, in a way or another, sooner or later, to the need for extra facilities (or a good bit of extra rework to existing facilities, on top of what would seem to be already required)... AresI/Orion + AresV/Altair (when AresV was still using 5 segment SRB and not the 5.5 seg. SRB for super-monster HLV iterations such as LV51.00.48/47, with 10m diameter core having a length greater than SaturnV's first and second stages together!) on the Constellation crewed lunar mission mode (and when only assuming 2 of such missions per year) could be 'safe' enough regarding the 'Quantity-Distance' (although already close to the limit with other mission assumptions) with the utilization of 1.5 sets of 5 segment SRB per crewed lunar mission (this is probably the origin of the '1.5 launch' designation (?), not sure, would have to verify)...

… Kind of similar thought could be made, under some circumstances, for eventual semi-parallel processing of two SDLV using a total of two sets of 4 seg. SRB (this is kind of the current QD limit, ~16 segments or so)...

… On another hand, two SDLV using a total of two sets of 5 segment SRB seems to be clearly beyond currently  accepted QD limits  (for cases where might be eventually desired to process two - or more - vehicles almost in parallel / 'quick' sequence).



Is the 5 segment SRB worth for the long-term?

As noted on the above references, these issues can be worked-around in several ways but these are some of the kind of considerations that make a liquid booster attractive (focusing on launch preparation, much less concerns about booster transportation / integration to/at the VAB, less loads on crawlerway / crawler, etc)... The 'drawback' – if it could be called that – would be the eventual need to develop a powerful kerolox engine... On another hand, the 5 seg. SRB is also requiring a development program too...

This all to say that these are the kind of things that need to be properly thought out in terms of not only near-future development cost but, more important, in terms of operation constraints / sustainability of eventual new launch vehicles on the long-term.

The 5 segment SRB seems to be an impressive booster but – and this is only my opinion – not sure if they are the most 'clever' approach, on the long-term, because of their associated  infrastructure costs for transport from factory to KSC, assembly there, transport to launchpad... all that vs their performance gain / enabler role.

As Ross has written, the current times are a key moment (and perhaps the last opportunity for NASA) to properly think about these questions and about if things such as the 5 seg. SRB are or not really worth (vs mission design assumptions and/or vs other eventual options for the hardware)...


All this boring text to write that share some concerns: if 'having to stay', for political purposes, with big solids it might then be better to stay with the 4 segment SRB on a somehow conservative SDLV design (but still allowing space for growth) and also think on alternative mission designs / international cooperation, etc... this unless something would really change and a strong political and economical commitment would be made to properly support other options, I mean... if there might exist big uncertainty on implementing something that goes much beyond the current STS ET heritage / 4 seg. SRB (either it be parallel or in-line) then maybe better to stay with the more or less known 'quantities' than going to stretched cores, heavier solids, etc in a quest for performance optimisation when such quest might not make sense vs the available resources and other eventual options to implement the missions (vs the mission requirements)...


On another hand, if wishing to use 5 segment SRB... Well, then the money to support such option really needs to be clearly 'there' for all the equipment and facilities upgrades (and eventual new KSC facilities)... and also to properly support that capability for many years to come (I'm not sure if such kind of money is included or not on the 'KSC modernization' parts of some recent language / intentions of political documents)... Else, it will all happen again, with a vehicle being designed for facilities that don't have enough resources to be upgraded / built to support such vehicle and / or with such development / operational money being used there instead of in other items required for the implementation of missions...

Antσnio
« Last Edit: 08/14/2010 10:00 am by simcosmos »
my pics @ flickr

Offline Captain Scarlet

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Is it true they are also called Hans and Franz?

Offline AnalogMan

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Is it true they are also called Hans and Franz?

It is!  :)

The names Hans and Franz come from the old Saturday Night Live skits with Dana Carvey and Kevin Nealon--they were characters called Hans and Franz-they were body-builders with the i guess German accent and they were here to pump you up.  :)  This was mentioned by a crawler driver in the 1994 Discovery channel program "The Space Shuttle"  thats how know about it.  :)

Offline nooneofconsequence

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Jupiter-130/246 stacked on a new ML with a full-size 750 ton Apollo/Ares-I style LUT (service and umbilicals combined) will exceed the Crawler's capabilities.
Not to be snarky, but AJAX 440 (e.g. no RSRMS) and you don't exceed the limits.

Sometimes doing the right thing at the right time has its advantages too.
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Offline luke strawwalker

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U/S mass. Thin, semi pressure stabalised ACES with RL10 v a heavy, self supporting S-IVB esque upper stage (possibly with loiter ring) and J2-X.

And massive 33 foot core + 6 (or 7?) RS-68's??  OL JR :)
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Online Chris Bergin

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