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3 minutes ago, tater said:

Doesn't really buy much even then. The Orion capsule is just too heavy. Adding a decent SM could be done, but then you get crew in a useful lunar orbit for surface access... and nothing to do there.

For some reason, SLS proponents seem to think that lunar orbit rendezvous is somehow easy, while Earth orbit rendezvous is impossibly difficult, and harms chances for mission success. Because reasons.

As dumb as some elements of Constellation were (crew riding right on top of an SRB is one), it got one thing right - removing crew from superheavy lift. Earth orbit rendezvous with an actually adequate translunar stage would have got Orion to low lunar orbit without a problem. That way, HLS contractors would only need to worry about landing from LLO.

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  • 2 weeks later...

Hello!

I have a question about SLS. Why is Artemis I still scheduled for November 2021? I recently read that the booster segments are going to be stacked over the next couple of weeks, and that the core stage is going to undergo final tests in December before heading to Cape Canaveral for integration. What makes the integration and vehicle assembly take all the way until November 2021? Doesn't assembling a rocket take only a few months, not almost a whole year?

Thanks!

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There's still argument over whether Nov is a no-later-than date or whether it's going to slip even further.

As for why Boeing/NASA is incapable of moving fast, I'd suggest an overabundance of caution and no financial incentive to go faster.

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Given that we're not going to see an unmanned test, and the first one will involve direct moon-return trip, I could understand it takes them longer.

Though it does puzzle me why they would consider that rather than having one unmanned test beforehand. Probably having to do with the yet-unfinalized 2nd stage design, not even the interim 2nd stage they want to use...

EDIT : Come to think of it, has the DCSS (basis for ICPS) ever been man-rated ? I wonder if using Centaur might've been better, since the man-rating would've gone together with Starliner...

Edited by YNM
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On 11/25/2020 at 4:54 AM, AeroSky said:

Hello!

I have a question about SLS. Why is Artemis I still scheduled for November 2021? I recently read that the booster segments are going to be stacked over the next couple of weeks, and that the core stage is going to undergo final tests in December before heading to Cape Canaveral for integration. What makes the integration and vehicle assembly take all the way until November 2021? Doesn't assembling a rocket take only a few months, not almost a whole year?

Thanks!

Despite the unavoidable delays imposed by COVID & the busiest hurricane season I’ve ever lived to see- SLS has only drifted 1 month off of the schedule I made back in July. I also ran the timeline past a Stennis SC worker & he agreed my timelines were close to what he expected based on their work.

The booster was predicted to arrive before the end of the year back in July. Now, I’m predicting arrival before the end of January.

Assembly & MLP integration by/before July. Testing close out by September, Wet Dress Rehearsal by or before November. Launch within that month is still possible, though likely early December for final prelaunch checks. 
 

Many of these dates also assume delays, meaning this is closer to a “worst case scenario” timeline. Any improvements or meeting deadlines ahead of schedule would bring back any of these dates back. Remember prior to COVID & hurricanes, the green run was ahead of schedule. So them getting ahead of my schedule is very likely. 

The biggest delay currently being Test 7 of the Green Run, something else I had predicted would be a cause of delay since this would be the first time the internal components of the vehicle such as valves & seals would be used. Not to mention I expected weather to have taken its toll on the vehicle considering its weathered (pun not intended) multiple hurricanes to this point. Especially given it’s a hydrolox fuel core, I knew that leaks (which is common with liquid hydrogen fuel tanks). So the news of the Test 7 delay isn’t all that surprising to me & only barely pushes the schedule I already have had planned for most of 2020. 

On 11/25/2020 at 6:38 AM, YNM said:

Given that we're not going to see an unmanned test, and the first one will involve direct moon-return trip, I could understand it takes them longer.

Though it does puzzle me why they would consider that rather than having one unmanned test beforehand. Probably having to do with the yet-unfinalized 2nd stage design, not even the interim 2nd stage they want to use...

EDIT : Come to think of it, has the DCSS (basis for ICPS) ever been man-rated ? I wonder if using Centaur might've been better, since the man-rating would've gone together with Starliner...

Artemis 1 is unmanned. Artemis 2 will be SLS’ first crewed flight.

ICPS is just a stretched DCSS, which as already considered for crewed flight for Orion Lite (before it was canceled) & Starliner. 

Artemis 1 will certify both SLS’ crew readiness & ICPS. 

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3 hours ago, ZooNamedGames said:

ICPS is just a stretched DCSS, which as already considered for crewed flight for Orion Lite (before it was canceled) & Starliner. 

Ah, right, Starliner was also supposed to be compatible with Delta IV.

Though honestly this would puzzle me more why they'd plan in such long timescales for integration. Wouldn't want to risk your hardware being flawed due to improper machining, sure, but also don't want to let the hardware sit around unused until it deteriorates either.

Edited by YNM
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https://www.theverge.com/2020/11/30/21726753/nasa-orion-crew-capsule-power-unit-failure-artemis-i

Quote

In early November, engineers at Lockheed Martin working on Orion noticed that a power component inside the vehicle had failed, according to an internal email and an internal PowerPoint presentation seen by The Verge. The component is within one of the spacecraft’s eight power and data units, or PDUs. The PDUs are the “main power/data boxes,” for Orion according to the email, responsible for activating key systems that Orion needs during flight.

Quote

To get to the PDU, Lockheed Martin could remove the Orion crew capsule from its service module, but it’s a lengthy process that could take up to a year. As many as nine months would be needed to take the vehicle apart and put it back together again, in addition to three months for subsequent testing, according to the presentation.

Lockheed has another option, but it’s never been done before and may carry extra risks, Lockheed Martin engineers acknowledge in their presentation. To do it, engineers would have to tunnel through the adapter’s exterior by removing some of the outer panels of the adapter to get to the PDU. The panels weren’t designed to be removed this way, but this scenario may only take up to four months to complete if engineers figure out a way to do it.

Yeesh.

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2 minutes ago, tater said:

Yeesh.

I read about this a couple of days back. 

Isn't it a bit of a design flaw that a critical component like this is so buried inside the vehicle that it takes months to fix? Shouldn't there be access panels that allow easier access to the PDUs?

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1 minute ago, RealKerbal3x said:

I read about this a couple of days back. 

Isn't it a bit of a design flaw that a critical component like this is so buried inside the vehicle that it takes months to fix? Shouldn't there be access panels that allow easier access to the PDUs?

Hey, they know what they're doing, they're not young upstarts!

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2 minutes ago, RealKerbal3x said:

Isn't it a bit of a design flaw that a critical component like this is so buried inside the vehicle that it takes months to fix? Shouldn't there be access panels that allow easier access to the PDUs?

Well sometimes there's nowhere else to place it due to other requirements. What they *should* have noted down was how long it can really last before going bad so they can actually use it and not leave it rot in a warehouse.

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1 minute ago, YNM said:

Well sometimes there's nowhere else to place it due to other requirements. What they *should* have noted down was how long it can really last before going bad so they can actually use it and not leave it rot in a warehouse.

Wouldn't have been a problem if SLS had launched on time in 2016, just saying... ^_^

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On 12/4/2020 at 1:59 AM, RealKerbal3x said:

Wouldn't have been a problem if SLS had launched on time in 2016, just saying... ^_^

Or if it hadn't been assembled alongside the other things, and only assembled once everything is ready.

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https://arstechnica.com/science/2020/12/six-years-after-orions-first-spaceflight-america-still-waits-for-an-encore/

His observation that Orion at the point that it flies will have cost substantially more than SpaceX is brutal (just Orion the capsule, not including the service module).

Not more than SpaceX spent on Crew Dragon, more than they have spent in total so far.

He doesn't expand on what will likely happen by the time a real Orion actually flies (all up, with crew, or capable of holding crew). Meaning by that time the all-in cost of SpaceX, every penny they will have spent since their inception will likely still be less than just the cost of the Orion capsule, and by early 2022, they will have more launches under their belt, more crew flown to ISS, possibly non-NASA crew mission(s), and it's entirely possible an orbital flight of Starship.

Edited by tater
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The absolute deal-breaker for me in SLS isn't ultimately the cost, or that it isn't big enough to do capsule and lander to the moon at once.

It's flight rate.

A high flight rate could cover all manner of sins. Can't co-manifest a lander? Send up another launch. Can't do Mars return without a mothership? Multiple-flight-construct that thing.

SLS will never have the flight rate to work unsupported. And this must have been known from the start. I just... I just don't understand how such a crititical component of a crewed BLEO programme gets missed. 

It's almost like NASA have prat-falled their way into a viable lunar programme:

"We'll make this booster and capsule to keep the senate happy, but we all know it's never going to acheive anything. Commercial launchers are coming along nicely though. Oh, wait... actually... Huh!"

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59 minutes ago, RCgothic said:

It's flight rate.

Surprise surprise, another reason SLS can't do the job it's supposedly meant for. You want to build a mothership for a Mars return mission? No problem, just start assembly five years before the transfer window.

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2 hours ago, RealKerbal3x said:

Surprise surprise, another reason SLS can't do the job it's supposedly meant for. You want to build a mothership for a Mars return mission? No problem, just start assembly five years before the transfer window.

Which doesn't work because you need multiple flights' worth of fuel and LH2 would all boil off between flights.

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