Author Topic: Leading Commercial Space Group Embraces SLS  (Read 27200 times)

Offline edkyle99

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Re: Leading Commercial Space Group Embraces SLS
« Reply #120 on: 02/12/2017 03:47 PM »
It's a BS claim, I'm surprised you're falling for it. It comes from the published payload limits of the payload adapter they use for commercial commsats, not the whole rocket. Not all payloads even use that adapter. In particular, Dragon doesn't use it.

Anyone can make a stupid video nowadays and spread FUD without evidence. We shouldn't encourage it and definitely shouldn't fall for it.
Perhaps, and we'll hopefully find out in due course, but the fact remains that Falcon 9, which is cataloged at 22+ tonnes to LEO, has never orbited more than the 10+ tonne structural limit discussed in the video.

 - Ed Kyle
« Last Edit: 02/12/2017 03:48 PM by edkyle99 »

Offline Robotbeat

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Re: Leading Commercial Space Group Embraces SLS
« Reply #121 on: 02/12/2017 03:52 PM »
I fail to see the point of posting a baseless claim like this. It's FUD, and without evidence or statement from a reputable source (SpaceX themselves, NASA, GAO, etc) we shouldn't give it the time of day, or we're just encouraging folks to lie.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline edkyle99

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Re: Leading Commercial Space Group Embraces SLS
« Reply #122 on: 02/12/2017 03:58 PM »
I fail to see the point of posting a baseless claim like this. It's FUD, and without evidence or statement from a reputable source (SpaceX themselves, NASA, GAO, etc) we shouldn't give it the time of day, or we're just encouraging folks to lie.
I believe it is fair to consider, given (A) the actual flight history of Falcon 9 (facts) and (B) the history of SpaceX performance claims (also documented facts), which are, and have long been, at odds with (A). 

 - Ed Kyle
« Last Edit: 02/12/2017 03:58 PM by edkyle99 »

Offline Oli

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Re: Leading Commercial Space Group Embraces SLS
« Reply #123 on: 02/12/2017 04:01 PM »
When comparing SLS to Falcon Heavy, which appears to have been done in this thread, it might be useful to ponder the assertion made in this video.  Falcon Heavy, the commentator says, can only lift a maximum of 10,886 kg to any orbit!

I've always wondered whether FH is structurally strong enough to lift 50t to LEO. It would make no sense at this point. I guess it would add significant mass to the second stage, lowering the GTO/Mars payload capability.
« Last Edit: 02/12/2017 04:01 PM by Oli »

Offline Robotbeat

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Re: Leading Commercial Space Group Embraces SLS
« Reply #124 on: 02/12/2017 04:04 PM »
No it wouldn't. The second stage while full is much heavier than 50 tons, and the force exerted by the upper stage is no greater with a big payload or a small one as it is determined by the engine thrust. A heavier payload would have lower acceleration, for instance.

The payload adapter area would need to be changed, but that's no different really than changing the area for Dragon vs commsat payloads, which use very different adapters.

You would need a different adapter, not a different rocket.

This story is BS.
« Last Edit: 02/12/2017 04:06 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Robotbeat

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Re: Leading Commercial Space Group Embraces SLS
« Reply #125 on: 02/12/2017 04:08 PM »
I fail to see the point of posting a baseless claim like this. It's FUD, and without evidence or statement from a reputable source (SpaceX themselves, NASA, GAO, etc) we shouldn't give it the time of day, or we're just encouraging folks to lie.
I believe it is fair to consider, given (A) the actual flight history of Falcon 9 (facts) and (B) the history of SpaceX performance claims (also documented facts), which are, and have long been, at odds with (A). 

 - Ed Kyle
It's not fair, because it's made as an assertion without evidence. If it were framed as a question, it'd be reasonable. The way it's worded now, it's the same thing as a lie.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Chris Bergin

Re: Leading Commercial Space Group Embraces SLS
« Reply #126 on: 02/12/2017 04:33 PM »
Adding "BS" to posts just makes your position seem incredibly weak. Try and use your indoor voices.

Offline Robotbeat

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Re: Leading Commercial Space Group Embraces SLS
« Reply #127 on: 02/12/2017 04:47 PM »
I use BS specifically. If you make an assertion as if something is a matter of fact when you have no evidence for it, it is BS. It's not exactly the definition of a lie, because you don't know for sure that it is false. BS is the best word.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline muomega0

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Re: Leading Commercial Space Group Embraces SLS
« Reply #128 on: 02/12/2017 05:24 PM »
When comparing SLS to Falcon Heavy, which appears to have been done in this thread, it might be useful to ponder the assertion made in this video.  Falcon Heavy, the commentator says, can only lift a maximum of 10,886 kg to any orbit!

I've always wondered whether FH is structurally strong enough to lift 50t to LEO. It would make no sense at this point. I guess it would add significant mass to the second stage, lowering the GTO/Mars payload capability.
This is such a narrow view of a LV architecture.  One shots has killed innovation.  Because of the inefficient SLS core design, they had to shift to highly elliptical orbits and then to L1, when L2 is superior in many many ways, staging in LEO first.   The US has to abandon larger LVs.  Flight rate provides demonstrated reliability.

The US does not require a LV greater than 10 to 20 mT.  If a LV can be increased in size to be more cost effective, then great.  But Congress wants to distribute the wealth, make things competitive, and perhaps just once wants to accomplish something for HSF that meets the 1958 Act.  Their record is poor so far.

So with a tweak to a previous post, four launches of 50mT LV would likely meet the NASA market, or would you rather have 5-10 launches from two different providers,  2-5 launches from 4 four different providers..... oh yea...HLV, we got ours  get your own.  Ironically, (an honest) single provider may be cheapest  ;D  Wonder if the 15% overhead on ACA could be reduced the same way, since 'the private sector' has not reduced costs for decades.

Vehicles don't matter(mostly). Missions matter. Funding matters. There needs to be more funding for NASA so there is proper funding to escape LEO.

Let's fund programs one hundred per cent instead of the partial funding that keeps programs from finishing on time, pushes them to the left, and makes them more expensive in the long run.
Low end, NASA needs to rotate crew to LEO with supplies in the 10mT range.
High end, Mars DRM 5 (yes issues) averages 200mT/yr:  HLVs cannot increase flight rate to reduce costs no need for reuse with 2 flights.
Then examine all the other payloads (where topping off in LEO takes advantage of Boeing's Amplification Factor)
   - - - >  a 10 to 20mT LV to LEO seems to be the right size < - - -

If you want to maximize jobs, actually accomplish objectives and make a difference in the world, create new markets (global worldwide internet 10X faster), and create many more challenges for the next generation that We Do Not Know How To Solve Now, then implement distributed launch with smaller LVs with the goal of complete reuse.

Offline Oli

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Re: Leading Commercial Space Group Embraces SLS
« Reply #129 on: 02/12/2017 05:55 PM »
No it wouldn't. The second stage while full is much heavier than 50 tons, and the force exerted by the upper stage is no greater with a big payload or a small one as it is determined by the engine thrust. A heavier payload would have lower acceleration, for instance.

The acceleration during first stage burn is far less dependent on the payload mass. Maximum (steady state) axial acceleration for the Delta IV Heavy during first stage burn is ~4.3g for 28t payload (vs ~5.2g for 5t payload). The max axial acceleration during second stage burn is ~0.4g for 28t payload (vs ~1.3g for 5t payload). Here.

And we haven't been talking about lateral acceleration, which seems to be more or less independent of the payload mass.
« Last Edit: 02/12/2017 06:00 PM by Oli »

Offline Robotbeat

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Re: Leading Commercial Space Group Embraces SLS
« Reply #130 on: 02/12/2017 06:00 PM »
And during first stage burn, force is dominated by upper stage propellant mass and loads on the fairing.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Oli

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Re: Leading Commercial Space Group Embraces SLS
« Reply #131 on: 02/12/2017 06:09 PM »
And during first stage burn, force is dominated by upper stage propellant mass and loads on the fairing.

The fairing is long gone at max g of the Delta Heavy first stage.

As for the propellant mass, not sure that load is transferred in a similar way through the stage. Also 50t on a 110t stage certainly matters. Otherwise I could argue the second stage load doesn't matter for the first stage.

Offline Toast

Re: Leading Commercial Space Group Embraces SLS
« Reply #132 on: 02/12/2017 06:30 PM »
Perhaps, and we'll hopefully find out in due course, but the fact remains that Falcon 9, which is cataloged at 22+ tonnes to LEO, has never orbited more than the 10+ tonne structural limit discussed in the video.

 - Ed Kyle

And Atlas V is claimed to be capable of launching with a dual-engine Centaur upper stage, but has never done so. And yet I'm not in doubt of it's capability to do so, and neither am I in doubt of the Falcon 9's capability to launch 22+ tonnes to LEO.

Offline Coastal Ron

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Re: Leading Commercial Space Group Embraces SLS
« Reply #133 on: 02/12/2017 06:33 PM »
When comparing SLS to Falcon Heavy, which appears to have been done in this thread, it might be useful to ponder the assertion made in this video.  Falcon Heavy, the commentator says, can only lift a maximum of 10,886 kg to any orbit!

Regarding this video, there are only two possibilities:

1.  SpaceX has been lying to the public and to potential customers about what Falcon Heavy is capable of doing, since they state on their website that Falcon Heavy is capable of lifting 54.4mT to LEO, and also what Falcon 9 is capable of doing, since SpaceX states it can lift 22.8mT to LEO.  The video claims both are limited to 10.9mT to any destination.

2.  The person or persons behind "Space Is Kind Of Cool" don't know what they are talking about, but they make authoritative looking videos.

Elon Musk may not be good at keeping schedules, but to my knowledge he has never lied, and in fact he tends to understate what his SpaceX products are capable of doing.

I would give no credence to this video.  It is FUD.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline edkyle99

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Re: Leading Commercial Space Group Embraces SLS
« Reply #134 on: 02/12/2017 06:47 PM »
I fail to see the point of posting a baseless claim like this. It's FUD, and without evidence or statement from a reputable source (SpaceX themselves, NASA, GAO, etc) we shouldn't give it the time of day, or we're just encouraging folks to lie.
I believe it is fair to consider, given (A) the actual flight history of Falcon 9 (facts) and (B) the history of SpaceX performance claims (also documented facts), which are, and have long been, at odds with (A). 

 - Ed Kyle
It's not fair, because it's made as an assertion without evidence. If it were framed as a question, it'd be reasonable. The way it's worded now, it's the same thing as a lie.

The evidence given in the video is from the attached Falcon 9 User's Guide, Section 3.3, Page 15.

Of course that is for Falcon 9, and the video author assumes the same PAF would be used for Falcon Heavy.  I agree that this is a bad assumption, because it should be obvious that SpaceX intends Falcon Heavy to compete for EELV Heavy payloads.  Delta 4 Heavy has almost certainly boosted 17-ish tonne payloads to near-polar orbits (actual mass classified), so Falcon Heavy would need to duplicate, and perhaps even better, that capability.

On the other hand, I don't expect to ever see a Falcon Heavy lift anywhere near 54 tonnes to any orbit.  Flight history suggests that actual payloads would weigh less than half as much.  SpaceX is using the capability for booster stage recovery.

 - Ed Kyle

Offline Oli

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Re: Leading Commercial Space Group Embraces SLS
« Reply #135 on: 02/12/2017 06:58 PM »
I would give no credence to this video.  It is FUD.

FUD or not, it's hardly relevant since I'm sure the FH could be upgraded for 50t payloads. I don't buy the "too long and thin" argument in the video. Lack of fairing volume is a more limiting factor.
« Last Edit: 02/12/2017 07:00 PM by Oli »

Offline woods170

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Re: Leading Commercial Space Group Embraces SLS
« Reply #136 on: 02/12/2017 07:44 PM »
I fail to see the point of posting a baseless claim like this. It's FUD, and without evidence or statement from a reputable source (SpaceX themselves, NASA, GAO, etc) we shouldn't give it the time of day, or we're just encouraging folks to lie.
I believe it is fair to consider, given (A) the actual flight history of Falcon 9 (facts) and (B) the history of SpaceX performance claims (also documented facts), which are, and have long been, at odds with (A). 

 - Ed Kyle
Ed, I've reminded you before that almost none of the launch vehicles in service today have ever actually lifted their stated max. payload mass to any orbit. Falcon 9 is no exception.

Offline Lar

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Re: Leading Commercial Space Group Embraces SLS
« Reply #137 on: 02/12/2017 08:05 PM »
The argument about the video is stale. Chris already warned once. Stop.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline ncb1397

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Re: Leading Commercial Space Group Embraces SLS
« Reply #138 on: 02/12/2017 08:57 PM »
Vulcan can't really be properly evaluated as an alternative to SLS.

Neither the SLS or the Vulcan are flying yet, so to some that makes them "paper rockets".  I don't ascribe to that philosophy, as I have no doubt that either Boeing or ULA can build a safe launch system, and we know enough about both to make valid assumptions.

The key difference to remember about the Vulcan vs the SLS is that the Vulcan will be ULA's only launch system for military, NASA and commercial payloads, meaning it will be flying many times per year.  The SLS will only fly with NASA payloads that can't fly on the Vulcan (or other commercial launchers), and is likely to fly less than twice per year.  The difference contributes to cost, and cost is the #1 barrier to expanding our use of space.

Quote
We still don't even know what engine/propellant it will be using. ULA was going to select an engine after a full BE-4 static fire that last I heard was going to be spring 2017. Maybe this could be revisited in a couple months.

For the most part, what engine they decide to use is immaterial.  That's because it only matters what the $/kg are to move mass to space, not how they do it.  Stop thinking like an engineer, think like a business person.

I mean what engine is used affects cost (and performance/reliability). Propulsion makes up a large percentage of a rocket's cost. We know what boosters SLS will use, we know the first stage engines, we know the upper stage engines on both the EUS and iCPS. Not only that, on SLS, we have a large data-set on cost of production going back many years on all propulsion elements. To answer "how much?", you first have to answer "what" and Vulcan isn't at that stage yet.

If BE-4 doesn't work out for ULA, and Vulcan just morphs into a re-engine of Atlas V with AR-1 engines, it really isn't that much more cost effective than SLS. AR-1 is projected to cost as much as RD-180. Based on the ULA Rocketbuilder website, you can get 18813 kg to LEO for 157 million. So, you would need to use 6 of these to replace one SLS Block 1B, at a cost of $942 million. Now if BE-4 costs $10 million less and allows you to use 1 less solid on a given mission, you start to get daylight, but still not enough to justify having to deal with re-orienting NASA and dealing with the constraints of smaller vehicles.

SLS has the added benefit of forcing Congress to come up with(and fund) more ambitious missions and more mass to lift into space, which I am not totally against. So far that is just Europa(with lander) and Orion, but there potentially is more and they were constrained by the last administration with regards to at least one potential payload.
« Last Edit: 02/12/2017 09:44 PM by ncb1397 »

Offline Oli

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Re: Leading Commercial Space Group Embraces SLS
« Reply #139 on: 02/12/2017 09:11 PM »
Because of the inefficient SLS core design, they had to shift to highly elliptical orbits and then to L1, when L2 is superior in many many ways, staging in LEO first.

The US does not require a LV greater than 10 to 20 mT.

- Not sure what you mean. The EMC assumes assembly in LDRO, which requires basically the same delta-v as L2 to get to (L1 requires more).
- For Mars the US certainly needs a LV greater than 20t.
« Last Edit: 02/12/2017 09:12 PM by Oli »

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