Author Topic: Discussion/Comparison of the new generation of American heavy lift launchers  (Read 15039 times)

Online envy887

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I was asking which ones specifically you find inconsistent.
All of them.  We have LSP's numbers (pre-Block-5?); then we have SpaceX published estimates (Block-5?); then we have member estimates (all over the map).  Not unexpected that they are inconsistent.
And what are your suggestions for improving this list?

Offline Coastal Ron

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Not to mention that ~6 mT comsats already are almost maxing out the fairing:
That doesn't look like a 5m fairing, and Falcon 9 fairing internal volume looks much bigger (see below with Jason 3 payload):

It is. Jason 3 is just tiny, only 553 kg.

Look at the shape of the fairings in the pictures. The first one is clearly conical, whereas the Falcon 9 one has a long, straight body in the middle.

ncb1397 could help clear this up by telling us what the payload was in the picture he supplied, and what the launcher was.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Online envy887

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Look at the shape of the fairings in the pictures. The first one is clearly conical, whereas the Falcon 9 one has a long, straight body in the middle.

ncb1397 could help clear this up by telling us what the payload was in the picture he supplied, and what the launcher was.
That's just the perspective.
The fairing is most definitely SpaceX's. The payload is Inmarsat 5 F4:
https://spaceflightnow.com/2017/05/15/photos-falcon-9-rocket-fourth-inmarsat-5-series-satellite-prepared-for-launch/

Offline Hyperion5

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Working backward from the Trans-Mars values published by SpaceX, I came up
with 5.6 tonnes TLI for F9B5 and 20.9 tonnes TLI for FH.  I'm honestly having
trouble seeing how Falcon Heavy meets its claimed payload goals, let alone the
numbers we've conjured in our guesstimates, unless it incorporates
yet-to-be-revealed improvements.  To be conservative, I'm putting these at
5.5 tonnes and 20.5 tonnes, respectfully.

 - Ed Kyle

Begging your pardon, Ed, but you didn't want to believe that the Falcon 9 v1.1 figures were sandbagged even after Shotwell had mentioned it had a 30% margin.  How else was a rocket with a better mass ratio and 60% more mass only delivering 30% more mass to LEO than a Falcon v1.0?  It didn't add up, which is what our work in L2 Simulation thread showed.  When they came out with new figures for the Falcon 9 v1.2FT & the Falcon Heavy a year ago, you also doubted those.  Now you're doubting the latest upward revision for the Falcon Heavy.  I'm pretty confident that the LV will hit the posted figures.  Why? 

The sims I worked on with Dmitry showed it was topping 62 tonnes to LEO BEFORE Block 5 came around.  The only reason why it was pushing less than 62 tonnes to LEO in our published sim was because Dmitry was purposely limiting the acceleration.  The reason for this astounding performance really comes down to good Isp and a truly outstanding mass ratio.  In fact, the Falcon 9's mass ratios are so good a Falcon 9 v1.2FT will actually deliver a greater percentage of its launch mass to GTO than an Centaur-topped Atlas 5.  The main reason for that loss?  The Atlas 5's main stage has a TERRIBLE mass ratio relative to the Falcon 9.  Steven Pietrobon calculated you could increase the Atlas' payload to GTO by 25% by doing nothing other than simply swapping in a better mass-optimized main stage with the same engine.  In fact I believe he created a thread discussing that discovery.  Lest we think a Falcon Heavy is as off the charts as it can get, consider the possibility of a Raptor upper stage being added.  Our sims showed such a vehicle delivering more than 78 tonnes to LEO, and that was before the recent posted increases in the boosters' & core stage's thrust. 

The one thing I am skeptical of is the posted Falcon Heavy payload to Pluto figure.  So far all work I've been a part of shows that would only be possible via an indirect (gravity slingshot) approach. 

Online envy887

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Ed, what's your source for the Vulcan numbers? The NASA OIG report on Exploration released a few months ago lists Vulcan-ACES as capable of 14 t to TLI and 10.5 t to TMI.
« Last Edit: 06/09/2017 02:27 AM by envy887 »

Offline Hyperion5

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Now you're doubting the latest upward revision for the Falcon Heavy. 
I have no basis to believe or to doubt the projected capabilities.  The truth is that no Falcon 9 has yet lifted anything close to the various capability claims made for the various versions through the years, but my problem with Falcon Heavy is that I simply haven't been able to conjure a model of this rocket that makes the LEO, GTO, TMI, etc. numbers converge.  I'm still trying.

 - Ed Kyle

By that standard, Ed, we'd have been scoffing at the Ariane 5's stated performance figures, because they didn't come close to maxing out its capabilities for years.  The G version, which was claimed to be capable of launching 6,950 kg to GTO from Kourou, first launched in 1996.  By the time the last Ariane 5 G flew in 2003, the rocket had never come close to maxing out its stated capability.  A better explanation was that satellite manufacturers have a long manufacturing and design lead time.  Thus they didn't design larger satellites until they were confident in the launcher.  Not too surprisingly, the Ariane 5 didn't start launching near-capacity satellites until the 6505 kg Tha´com-4/iPStar-1 in 2005, some 9 years after its initial launch, and by then they were already flying a more capable version.  We should not conclude that not maxing out a rocket's capabilities is evidence that it is incapable of stated performance figures.  Just ask the folks at Ariane. 

Online Lars-J

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Now you're doubting the latest upward revision for the Falcon Heavy. 
I have no basis to believe or to doubt the projected capabilities.  The truth is that no Falcon 9 has yet lifted anything close to the various capability claims made for the various versions through the years

As long as you apply that same yardstick to ALL launchers, people would complain far less. It does seem like something you only do for SpaceX, however, which rubs people the wrong way.

Online envy887

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Ed, what's your source for the Vulcan numbers? The NASA OIG report on Exploration released a few months ago lists Vulcan-ACES as capable of 14 t to TLI and 10.5 t to TMI.
I was extrapolating from the numbers presented on this, and similar, ULA charts.  Perhaps ULA has upgraded its performance estimates since this chart was released.

 - Ed Kyle
At least some of the data on that chart is from 2015 (e.g. F9 v1.2 is a "future vehicle"), so the Vulcan numbers might be out of date.

Online envy887

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The 2-stage version is claimed to be able to get 13 tonnes to GTO, so the second stage must be pretty efficient and perhaps lighter (smaller) than it appears in the illustrations.  Pretty amazing when you think about it really - more payload than any two-stage rocket in service (and this with first stage recovery).  My guess today for New Glenn 2-stage is 8.5 tonnes TLI and 5 tonnes Trans-Mars based on the following guesstimates.  (Ask me tomorrow and I might guess differently).

S1  1,250 tonnes > 125 tonnes, ISP 329 sec
S2  155 tonnes > 12.37 tonnes, ISP 360 sec
PLF 4 tonnes

PL = 45 tonnes, delta-v = 9200 m/s
PL = 13 tonnes, delta-v = 11720 m/s
PL = 8.5 tonnes, delta-v = 12,350 m/s
PL = 5 tonnes, delta-v = 12,950 m/s

Your 125 tonne upper stage would have to stage at nearly 4,000 m/s, putting the booster through 10x the reentry heat load compared to F9, plus BO is not planning on an entry burn. That's... not happening.

You models derive far too much from EELV. Try modeling it after Falcon 9 - as Blue Origin certainly has. There is no way the upper stage is 1/10 the size of the booster, it's more like 1/5. Measuring the section view Blue has published will confirm this. From multiple analyses including modeling after Falcon 9, measuring the published renderings, optimizing for a staging velocity around 2000 m/s, and assuming a TWR near 1 at staging with a 280 tonne-force BE-4U, I estimate the upper stage will mass 260 to 290 tonnes.

If Blue is targeting not-quite state of the art mass fractions of about 6.5%, a yields a upper stage mass of about 18 tonnes. With a GLOM about 1400 tonnes it can stage at 1,850 m/s and still send 14 tonnes to GEO-1800 from the Cape (I'm assuming 365s Isp for BE-4U).

While it does just fine to GTO, that big upper stage really hurts payload to higher energy trajectories. I get right around 8000 kg translunar, which is still impressive for a 2-stage vehicle with a reusable booster.

But that, of course, is where the 3-stage version comes in.
« Last Edit: 06/09/2017 06:55 PM by envy887 »

Online envy887

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I wonder if it would be cheaper for Blue to put that 3rd stage directly on the booster to start with... It would still compete with F9R to GTO, and expend a much smaller stage with each launch.

But yes, the 3 stage New Glenn is going to be a beast to high orbits...

Online Lars-J

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I wonder if it would be cheaper for Blue to put that 3rd stage directly on the booster to start with... It would still compete with F9R to GTO, and expend a much smaller stage with each launch.

But yes, the 3 stage New Glenn is going to be a beast to high orbits...

Yes the 2nd stage does appear oversized.

But my theory is that those 2nd and 3rd stage are completely notional and meant to confuse competitors. I think they are working on a reusable upper stage instead, but that's my conspiracy theory of the day. :)
« Last Edit: 06/10/2017 05:31 AM by Lars-J »

Online GWH

They have already stated intent to reuse 2nd stage as a future upgrade.

Offline TrevorMonty

For BLEO missions with 3rd stage and expendable 2nd stage is likely to maximize performance. So developing simpler expendable 2nd stage first makes sense. Later on develop a reusable version for LEO missions.

Where crew vehicle fits into this development program remains to be seen. I'm picking small 6 person first that could do BLEO missions as well, followed by larger version (20? person) for LEO and maybe BLEO using New Armstrong.

Sent from my SM-G570Y using Tapatalk


Online envy887

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Some more information on SLS payload capacity released today. Doesn't look like Block 2 will hit 50 tonnes to TLI or 40 tonnes to Mars. SLS Block 2 should be listed as 37,600 kg to TMI and 45,000 kg to TLI. Block 1B estimates appear to be pretty accurate though...
« Last Edit: 06/16/2017 03:15 AM by envy887 »

Offline Paul451

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Some more information on SLS payload capacity released today. Doesn't look like Block 2 will hit 50 tonnes to TLI or 40 tonnes to Mars. Block 1B estimates appear to be pretty accurate though...

From the figures, I can't see the value of Block 2. Other than meeting the technical LEO requirements of the legislation, it doesn't add enough to actual BLEO mission payloads to be worth the money and time.

Online Khadgars

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Some more information on SLS payload capacity released today. Doesn't look like Block 2 will hit 50 tonnes to TLI or 40 tonnes to Mars. Block 1B estimates appear to be pretty accurate though...

From the figures, I can't see the value of Block 2. Other than meeting the technical LEO requirements of the legislation, it doesn't add enough to actual BLEO mission payloads to be worth the money and time.

Agreed.  I think they will stick with 1B imo.

Offline FinalFrontier

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Just out of curiosity and I might already know the answer but why is ITS not included?

I am assuming because it has no set timeline yet per say.
3-30-2017: The start of a great future
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Offline TrevorMonty

Here is ULA Distributed Launch info for a comparsion. For outer solar system missions >80km/s DL is better and probably lot cheaper.

http://cloud.tapatalk.com/s/5943030d82c1f/Distributed-Launch-2015.pdf

Online Eric Hedman

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Just out of curiosity and I might already know the answer but why is ITS not included?

I am assuming because it has no set timeline yet per say.

Here is the latest timeline I was able to find:

http://online.liebertpub.com/na101/home/literatum/publisher/mal/journals/content/space/2017/space.2017.5.issue-2/space.2017.29009.emu/20170602/images/large/figure19.jpeg

It was part of this article that says much more:
 
http://online.liebertpub.com/doi/full/10.1089/space.2017.29009.emu

Offline FinalFrontier

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Thanks for the links.

Still even with ITS possibly off the table between Vulcan Falcon and New Glenn there seems to be no point in SLS existing.
3-30-2017: The start of a great future
"Live Long and Prosper"

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