Author Topic: SLS EM-1 & -2 launch dates realign; EM-3 gains notional mission outline  (Read 54087 times)

Offline Proponent

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For example, the Apollo TLI stage was about 320,000 pounds, placed by a single launch into a very low Earth orbit of about 90 statute miles circular, on later missions.  You could have put up that many tons of mass in something like 40 Atlas launches, or 20 Titan II launches, or six to eight Saturn IB launches.  So, by that logic, the Saturn V was a useless waste of money.

But... each individually launched payload needs its own structure, its own avionics, its own maneuvering and attitude control system... so your one-launch TLI stage weighs 320,000 pounds, but 40 individually-launched piecework payloads will weigh on the order of half a million pounds.  And can't be placed in an unstable parking orbit, because it will take weeks, if not months, to assemble them all into the piecework variant of an Apollo TLI stage, so your initial energy requirements, just to get to LEO to assemble, go up.

Just comparing tonnage is like making deep space exploration into Lego elements.  It woefully fails to account for an enormous host of other factors that come into play when you piece-meal an exploration stage into being from tens to hundreds of individually-launched payloads.

This is a very valid and important point.  But it's only one of the factors that need be considered in deciding whether a heavy lifter is a good idea.  To my knowledge, no professional study of any BEO mission has compared architectures with and without heavy lift for anything NASA is likely to be tasked with anytime soon and concluded that heavy lift is the way to go.  SLS has as yet literally no technical justification.

Though I'm very skeptical of SLS's value, I wouldn't say that the Saturn V was a useless waste of money.  It performed very well in accomplishing the task: getting to the moon before the Soviets.  NASA could have sent people to the moon with smaller rockets.  That may well have been cheaper (and more sustainable) but probably also slower.  Back then, time was more important than money.  Now it's the other way around.  The utility of heavy lift needs to be evaluated in that context.
« Last Edit: 09/28/2017 06:09 pm by Proponent »

Offline TrevorMonty

The only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need.   
Commercially developed  DL and 3 vehicles in this class are now in development,  only 5-7yrs to late.

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Offline AncientU

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The only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need.   
Commercially developed  DL and 3 vehicles in this class are now in development,  only 5-7yrs to late.

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Never too late... just wishful thinking TM.
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Offline oldAtlas_Eguy

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Back to the dates.

Because the pad/VAB rebuild time to go from an SLS 1A to an SLS 1B has been stated unequivocally as being a duration of 30 months, this is where the notional EM-2 date of 1 June 2022 seems to spring from. But here is the catch. The mods can not be made until EM-1 is launched. So the date will slip day for day as EM-1 slips and there are no recourse for mitigation of the schedule impact to the EM-2 launch date. Specifically that 30 months is 24 months of pad/VAB rework followed by hardware arrival for fit checks and pad processing flows over a period of 6 months. So the 30 months is a hard launch to launch span irregardless of anything else. Unfortunately that duration cannot be shortened but many things could cause it to lengthen.

But if there is an additional requirement that the EUS fly unmanned like on the EC mission then that date is very notional. But the article does give some interesting mission plans for the various go-nogo points, one of which outlined for the EM-3 mission is prior to the EUS burn the EUS+Orion+ is placed in LEO in a very rapid decaying orbit such that Orion would return if EUS fails it checks while on orbit before a burn. So maybe the safety concerns in requiring flying the EUS on an unmanned mission prior to a manned one may be adequately answered.

Again in reference to EC the 30 month rule still applies because it is all because of the change from a 1A to a 1B. So the earliest a EC mission could take place is also that 1 June 2022 date.

Offline Zed_Noir

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So it is a race between the newly announced SpaceX BFR flight to Mars and the SLS EM-2 test flight in 2022 to see which one get off the pad first.  ;D

Pass the popcorn for the forthcoming launches

Offline tesla

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No SpaceX discussion here.
SLS is the real rocket and not an impossible concept suggested by an eccentric billionaire.
Go SLS and Orion! God bless America.

Offline woods170

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No SpaceX discussion here.
SLS is the real rocket and not an impossible concept suggested by an eccentric billionaire.
Back in 2010 the concept of doing an RTLS of a an orbital-class rocket booster also seemed to be an impossible concept. And yes, it was suggested by that same eccentric billionaire (with the difference that Elon wasn't a billionaire back then).

Offline MATTBLAK

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No SpaceX discussion here.
SLS is the real rocket and not an impossible concept suggested by an eccentric billionaire.
SLS hasn't even been presented as a set of test stages yet - even though it's design is relatively mature and feasible. And don't bring Elon's BFR into the discussion for now - though it is a difficult, slightly improbable design; not an impossible one just yet ;)

And sometimes; eccentric billionaires change the world.
« Last Edit: 09/29/2017 07:22 am by MATTBLAK »
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Offline Proponent

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The only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need.   
Commercially developed  DL and 3 vehicles in this class are now in development,  only 5-7yrs to late.

This is the same fallacy in another form:  you identify one weakness of a non-heavy-lift approach and conclude that heavy lift is better.  The fact remains that there is as yet literally no technical justification for SLS.

Offline AncientU

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No SpaceX discussion here.
SLS is the real rocket and not an impossible concept suggested by an eccentric billionaire.

Nothing to compare.
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline oldAtlas_Eguy

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I have a question about what NASA means by a Launch Readiness Date (LRD)?

My interpretation is that the vehicle is stacked, been moved out to the pad, is all checked out with the pad GSE, and is ready for a dry and then a wet dress rehearsal followed by a launch if the other two are uneventful.

So correct me if my interpretation is wrong. A hard and fast definition of what this milestone means is required to really understand when an actual launch will take place. If there is significant number of tasks still to take place after this milestone then an EM-2 LRD can still slip if problems occur between this milestone and actual launch. If it takes longer than the planned nominal duration then the LRD for EM-2 slips by the amount that the duration is greater than the nominal/planned/scheduled. But then again since EM-2 is also nearly a new vehicle with new GSE it is likely to experience similar snags and delays as that experienced by EM-1 during its processing and effort to launch.

So the 1 June 2022 date can be said to be one thing. The EM-2 launch will occur several months after that date.

Offline Khadgars

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So it is a race between the newly announced SpaceX BFR flight to Mars and the SLS EM-2 test flight in 2022 to see which one get off the pad first.  ;D

Pass the popcorn for the forthcoming launches

I do in-fact believe BFR will fly, or something close to it.  But I would add 10 years to the schedule, so 2032 would be first test flight of BFR IMO.  For the 2020s, SLS/Orion will have plenty to do.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline Khadgars

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The only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need.   
Commercially developed  DL and 3 vehicles in this class are now in development,  only 5-7yrs to late.

This is the same fallacy in another form:  you identify one weakness of a non-heavy-lift approach and conclude that heavy lift is better.  The fact remains that there is as yet literally no technical justification for SLS.

The same can be said to your argument "The fact remains that there is as yet literally no technical justification for SLS".  Technical justification?  That is as subjective a "fact" as any.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline RonM

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So it is a race between the newly announced SpaceX BFR flight to Mars and the SLS EM-2 test flight in 2022 to see which one get off the pad first.  ;D

Pass the popcorn for the forthcoming launches

I do in-fact believe BFR will fly, or something close to it.  But I would add 10 years to the schedule, so 2032 would be first test flight of BFR IMO.  For the 2020s, SLS/Orion will have plenty to do.

There will be delays for BFR, although 10 years is pessimistic. Congress will continue funding SLS/Orion at least until BFR is operational. So, I agree SLS/Orion will probably be operational in the 2020s. That will get DSG deployed. Even with BFR flying, DSG will be a useful asset as a transportation hub in cislunar space.

Offline UltraViolet9

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For the 2020s, SLS/Orion will have plenty to do.

I dunno.  It's late 2017.  For that statement to become true, the payload hardware needs to be in mid- to late-development now.  Since Apollo, NASA human spacecraft programs (STS, ISS, Orion) have required a decade or more to design, develop, launch, and become operational.

Even if DSG gets the go-ahead soon and doesn't encounter the schedule issues of those earlier programs, the emergence of ITS and similar reusable upper stages/spacecraft/landers on an early 3030s timetable would make DSG obsolete soon after completion.

NASA should _not_ bet the farm on SpaceX or BFG/ITS.  But what little insurance and utility SLS/Orion provides does not seem worth its high expense and large opportunity cost given the portfolio of Falcon Heavy, Vulcan/ACES, New Glenn/Blue Moon, New Armstrong, and BFG/ITS that NASA should be preparing for.

It would be a better use of the nation's resources and the NASA civil servant/contractor workforce to start reorienting NASA's human space flight program away from ETO transportation and towards BEO missions, payloads, and infrastructure, especially for planetary surfaces.

Sooner than later, IMO.  YMMV...
« Last Edit: 09/29/2017 10:43 pm by UltraViolet9 »

Offline A_M_Swallow

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I dunno.  It's late 2017.  For that statement to become true, the payload hardware needs to be in mid- to late-development now.  Since Apollo, NASA human spacecraft programs (STS, ISS, Orion) have required a decade or more to design, develop, launch, and become operational.

Even if DSG gets the go-ahead soon and doesn't encounter the schedule issues of those earlier programs, the emergence of ITS and similar reusable upper stages/spacecraft on an early 3030s timetable would make DSG obsolete soon after completion.
{snip}

EM-2 is aiming for 2022. If ITS is 2030+ that give DSG 10-15 years before a rival turns up. ITS is SpaceX only where as DSG could be hosting several lunar landers from different manufacturers.

Offline JohnF

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One thing to keep in mind is the longer it takes to get SLS/Orion flying, the longer the folks working on SLS/Orion have jobs, it's not like there will be thousands of these things manufactured on an assembly line, wouldn't be surprised if the dates slip further and further.

Offline envy887

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I dunno.  It's late 2017.  For that statement to become true, the payload hardware needs to be in mid- to late-development now.  Since Apollo, NASA human spacecraft programs (STS, ISS, Orion) have required a decade or more to design, develop, launch, and become operational.

Even if DSG gets the go-ahead soon and doesn't encounter the schedule issues of those earlier programs, the emergence of ITS and similar reusable upper stages/spacecraft on an early 3030s timetable would make DSG obsolete soon after completion.
{snip}

EM-2 is aiming for 2022. If ITS is 2030+ that give DSG 10-15 years before a rival turns up. ITS is SpaceX only where as DSG could be hosting several lunar landers from different manufacturers.
F1 took 6 years. F9 took 4 years. Even FH will take about 6 years.

I don't think SLS has 15-20 years without significant competition.

Offline UltraViolet9

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EM-2 is aiming for 2022.

The DSG won't be complete and have an airlock until 2026.

And that schedule holds only if the Administration and Congress approve the DSG soon.

The DSG will also need to evade the kind of weak rationales, political tinkering, changing partnerships, and multiple redesigns that put Alpha/Freedom/ISS in development hell for over a decade.

DSG is obviously simpler than ISS.  But even if it's approved soon, based on more recent experience with our "simple" Orion, I doubt DSG can avoid similar (if not quite as long) delays as ISS and Orion.

Quote
If ITS is 2030+ that give DSG 10-15 years before a rival turns up.

I don't think ITS is the only "rival".  Blue Moon or an ACES lander don't need the DSG and can use multiple launchers.  Even the little guys like Moon Express don't talk about DSG.

I doubt ULA will pursue an ACES lander without NASA skin in the game.  But Blue Origin certainly has a backer with deep enough pockets to bring Blue Moon forward in whatever timeframe he wants.

Quote
ITS is SpaceX only where as DSG could be hosting several lunar landers from different manufacturers.

In Blue Origin, SpaceX, and ULA, the US has three very capable launch operators and manufacturers who are each interested in building large reusable upper/transit stages and human-scale planetary landers.  Two are self-motivated and resourced enough to do it on their own.

Instead of trying to steer these companies towards a small station in lunar orbit that none of them have expressed much enthusiasm for, NASA should be trying to assist, accelerate, and build upon their efforts.

With this kind of triply-redundant industrial base, I don't see a need for NASA to be in (or get back into) the launch development/operation, chemical upper/transit stage, or routine large planetary lander business anymore.

Research, technical/facilities assistance, development cost-sharing, qualification, and service procurements, sure.  But no more design, development, test, and operation in these areas.  Leave that to industry, as it should be when an industry has multiple, healthy competitors.

Instead, put the enormous resources going towards SLS/Orion and potentially DSG into human planetary missions and payloads.  IMO, NASA's human space flight program should be regearing as soon as possible to become a planetary surface research, mobility, mission, ISRU, and infrastructure program.  Maybe with some nuclear or high-power electric transit stage work.  That's what industry is not doing and where the hardest problems lie. 

YMMV...


« Last Edit: 09/30/2017 12:30 am by UltraViolet9 »

Offline A_M_Swallow

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EM-2 is aiming for 2022.

The DSG won't be complete and have an airlock until 2026.

And that schedule holds only if the Administration and Congress approve the DSG soon.

The DSG will also need to evade the kind of weak rationales, political tinkering, changing partnerships, and multiple redesigns that put Alpha/Freedom/ISS in development hell for over a decade.

DSG is obviously simpler than ISS.  But even if it's approved soon, based on more recent experience with our "simple" Orion, I doubt DSG can avoid similar (if not quite as long) delays as ISS and Orion.

Quote
If ITS is 2030+ that give DSG 10-15 years before a rival turns up.

I don't think ITS is the only "rival".  Blue Moon or an ACES lander don't need the DSG and can use multiple launchers.  Even the little guys like Moon Express don't talk about DSG.

I doubt ULA will pursue an ACES lander without NASA skin in the game.  But Blue Origin certainly has a backer with deep enough pockets to bring Blue Moon forward in whatever timeframe he wants.

{snip}

To support lunar operations the DSG does not need an airlock, just two docking ports. However when fitted the airlock will permit EVAs to repair the landers. (80:20 rule)

NASA needs to duck political meddling, possibly by getting extra features included in additional modules. Some of the modules may even arrive.

If there is significant messing around with the habitation modules requirements NASA can simply buy and fit a B330 from Bigelow as a 'temporary' measure.

The ACES lander does not have a heat shield so it cannot reenter. To be reusable therefore the lander needs leaving in either lunar orbit or LEO. A second ACES transfer stage that pushes a capsule, able to reenter, to DSG permits manned Moon landings.

Currently most landers are expendable since their main bodies do not have heat shields and at the present time there is no where in space they can be refuelled.

Tags: artemis 3 SLS Artemis 1 
 

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