Author Topic: SpaceX Falcon Heavy Discussion (Thread 6)  (Read 533367 times)

Offline TomH

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #580 on: 04/23/2018 11:48 pm »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen

SLS Manifest Options:

The decision to keep SLS in its Block 1 configuration and launching off ML-1 deep into the 2020s now leaves NASA with some decision points.

At one stage, NASA was expecting to use the Block 1 with DCSS configuration just once, on the EM-1 mission. Now it is expected it will return to the previous plan of mirroring EM-1 (uncrewed Orion) and EM-2 (crewed Orion) on matching missions and rocket configurations. However, due to Orion readiness, it is unlikely both missions will close the previous multi-year gap by any notable margin.

What is becoming an option for bridging that gap between flights is using SLS to launch the flagship Europa Clipper mission in 2022. Originally, Europa Clipper was to use a Block 1B SLS to allow the EUS to be flight-proven before launching a crewed mission.  NASA then decided that a crew could launch on the first Block 1B on a non-flight proven EUS.

Now, with Block 1B many years away, NASA is looking at launching the Europa Clipper mission on a Block 1 SLS, a flight sometimes referred to as SM-1 (Science Mission -1) on documentation. Other documentation confusingly calls it EM-2, likely in some cheeky way of satisfying politically-driven schedules for SLS to fly “EM-2” by a certain date.

Inquiries are taking place into the loss of mission performance per Europa Clipper flying on the Block 1 versus Block 1B SLS. A major selling point of flying the Europa mission on an SLS Block 1B was using the EUS to shave many years off the transit time compared to “currently” available rocket options at the time the mission’s launch vehicle was first discussed.

Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

Online vaporcobra

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #581 on: 04/24/2018 01:02 am »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon 9/Heavy and still get  Clipper to Europa faster and several times cheaper than SLS w/ ICPS.
« Last Edit: 04/24/2018 01:05 am by vaporcobra »

Offline IanThePineapple

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #582 on: 04/24/2018 01:07 am »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon and still get the Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

What ever happened to the Raptor upper stage concept? I know the Air Force paid for some of its development, but I haven't heard anything about it since 2015 or 2016.

Are they just waiting on BFR, or maybe stock FH is already enough?

Offline daveklingler

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #583 on: 04/24/2018 01:16 am »
Hans' NEAF 2018 talk had some quasi-updated specs and details for Falcon Heavy, and they of course contradict what's on SpaceX's website :D

Quote
•   Falcon Heavy: 20t to GTO & 13t to TMI (website: 26.7t & 16.8t)
...(snip)
o   “[Crossfeed] may be introduced a bit later on”

That's a bit significant. Any elaboration on that?

Online vaporcobra

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #584 on: 04/24/2018 01:24 am »
Hans' NEAF 2018 talk had some quasi-updated specs and details for Falcon Heavy, and they of course contradict what's on SpaceX's website :D

Quote
•   Falcon Heavy: 20t to GTO & 13t to TMI (website: 26.7t & 16.8t)
...(snip)
o   “[Crossfeed] may be introduced a bit later on”

That's a bit significant. Any elaboration on that?

Nope, just the brief few words. It was a response to a question, but the questions were basically inaudible in the recording.

Online vaporcobra

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #585 on: 04/24/2018 01:33 am »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon and still get the Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

What ever happened to the Raptor upper stage concept? I know the Air Force paid for some of its development, but I haven't heard anything about it since 2015 or 2016.

Are they just waiting on BFR, or maybe stock FH is already enough?

Stock FH is very likely not capable of competing 1:1 with DIVH/Atlas 551 thanks to Centaur. Direct GEO insertion and interplanetary stuff is where FH still falls short as a result of upper stage inefficiency.

As for the Rapter US, I haven't heard anything. The most recent RFP (the one for entire new EELVs) basically only discussed the USAF's Raptor funding as an effort to development propulsion systems, not a replacement upper stage. Perhaps SpaceX's proposal will be a RUS for Block 5 F9 and FH, if they don't push for BFR.

Offline IanThePineapple

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #586 on: 04/24/2018 01:34 am »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon and still get the Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

What ever happened to the Raptor upper stage concept? I know the Air Force paid for some of its development, but I haven't heard anything about it since 2015 or 2016.

Are they just waiting on BFR, or maybe stock FH is already enough?

Stock FH is very likely not capable of competing 1:1 with DIVH/Atlas 551 thanks to Centaur. Direct GEO insertion and interplanetary stuff is where FH still falls short as a result of upper stage inefficiency.

As for the Rapter US, I haven't heard anything. The most recent RFP (the one for entire new EELVs) basically only discussed the USAF's Raptor funding as an effort to development propulsion systems, not a replacement upper stage. Perhaps SpaceX's proposal will be a RUS for Block 5 F9 and FH, if they don't push for BFR.

I think a RUS could also be used with Cargo BFR as a third stage, similar to the Shuttle-Centaur concept.

Offline CuddlyRocket

Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #587 on: 04/24/2018 03:39 am »
As for the Rapter US, I haven't heard anything. The most recent RFP (the one for entire new EELVs) basically only discussed the USAF's Raptor funding as an effort to development propulsion systems, not a replacement upper stage. Perhaps SpaceX's proposal will be a RUS for Block 5 F9 and FH, if they don't push for BFR.

I think a RUS could also be used with Cargo BFR as a third stage, similar to the Shuttle-Centaur concept.

The BFS is a Raptor upper stage!

Offline guckyfan

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #588 on: 04/24/2018 05:53 am »
The BFS is a Raptor upper stage!

But not a third stage. A third stage would make a fine addition for probes to the outer solar system avoiding expending a BFS for that purpose.

Offline speedevil

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #589 on: 04/24/2018 06:17 am »
The BFS is a Raptor upper stage!

But not a third stage. A third stage would make a fine addition for probes to the outer solar system avoiding expending a BFS for that purpose.
Raptor might be a bit high thrust.
Even if it can throttle to 60 tons, that's quite a high G at the end of a burn with a total 150 ton payload mass into LEO.


Offline guckyfan

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #590 on: 04/24/2018 06:31 am »

Raptor might be a bit high thrust.
Even if it can throttle to 60 tons, that's quite a high G at the end of a burn with a total 150 ton payload mass into LEO.

That third stage can be dry mass during launch, fuelled only in LEO by the refuelling runs, so quite big. The payload can also be quite heavy. Worst case ballast it for a small payload. Though throwing ballast to Pluto seems a weird concept.

Offline woods170

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #591 on: 04/24/2018 10:39 am »
Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

No, it didn't. Europa Clipper launching on SLS is written into law. And it was done so to provide SLS with additional payload(s) to justify its very existence.

As long as SLS remains US Congress' pet project Europa Clipper doesn't stand a chance of launching on another launcher, let alone FH.

Offline woods170

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #592 on: 04/24/2018 10:40 am »
The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon 9/Heavy and still get  Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

[Jim]
Stop daydreaming.
[/Jim]
« Last Edit: 04/24/2018 10:41 am by woods170 »

Offline AncientU

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #593 on: 04/24/2018 01:31 pm »
...

Stock FH is very likely not capable of competing 1:1 with DIVH/Atlas 551 thanks to Centaur. Direct GEO insertion and interplanetary stuff is where FH still falls short as a result of upper stage inefficiency.

As for the Rapter US, I haven't heard anything. The most recent RFP (the one for entire new EELVs) basically only discussed the USAF's Raptor funding as an effort to development propulsion systems, not a replacement upper stage. Perhaps SpaceX's proposal will be a RUS for Block 5 F9 and FH, if they don't push for BFR.

Not according to these calculations...

Cross-posted:
Three years to human rate ICPS and make Orion suitable for astronauts!?

Where does that information come from?

It's possible to interpret the prolonged delay of EUS as evidence that perhaps the software issues are predominantly related to EUS, and that the software for the rest of SLS is more mature because "heritage hardware."

EUS is still being designed. Any software issues are more likely due to elements that are being built now.

For those interested, Block I payload to Europa is only 2.9 t, compared to 8.1 t for Block IB. I estimate FH expendable payload for Europa (for 6,783 m/s delta-V from LEO) to be 6.5 t!

Steven: do you happen to know how much Vulcan/Centaur V with 6x solid boosters could throw at Jupiter?

I modified the Falcon Heavy program and made a few guestimates of the Vulcan second stage. From the drawing, I got a propellant mass of 56.2 t and a dry mass of 5.0 t. Extrapolating using RL10C-1 engines, 34.9 t LEO payload and 7.1 t GEO payload, I got only a 964 kg payload to Europa! Need to either use a solid third stage, flyby's or refuelling the second stage to get better performance.

Attached is the program I used to calculate performance.

Note that the first version I posted overestimated the Vulcan second stage propellant and dry mass, giving only a 105 kg payload mass to Europa.
« Last Edit: 04/24/2018 01:33 pm by AncientU »
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Offline Kansan52

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #594 on: 04/24/2018 02:48 pm »
Thanks!

Offline Ultrafamicom

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #595 on: 04/24/2018 03:42 pm »
Will the Block 5 version come closer to the web site numbers?

My assumption is that Hans' 20t and 13t figures are for missions that expend the center core, per Musk's recent tweets on the subject. It's a long shot from "~10%," but Musk issss known for his optimism... ;D

Quote
Side boosters landing on droneships & center expended is only ~10% performance penalty vs fully expended. Cost is only slightly higher than an expended F9, so around $95M.

Before M1D++was introduced, FH's payload stated on their website was exactly 13t to Mars and 21t to GTO, so it seems these figures are just the expendable capacity of the already flown Block3 FH without thrust and"structural upgrade"(per Mr.Musk)

Offline Jim

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #596 on: 04/24/2018 04:10 pm »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon 9/Heavy and still get  Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

No, just stop.

Offline LouScheffer

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #597 on: 04/24/2018 04:40 pm »
Stock FH is very likely not capable of competing 1:1 with DIVH/Atlas 551 thanks to Centaur. Direct GEO insertion and interplanetary stuff is where FH still falls short as a result of upper stage inefficiency.

For direct to GEO insertion, FH makes up for upper stage inefficiency by brute force.   Per the comments above, FH with barge landings for the sides and expended center core can put 20t into GTO.  Now to get to GEO needs 1800 m/s, which is a mass ratio of about 0.639.  So after the GEO insertion burn, the stack will mass about 12.75t.  Subtract 5t for the second stage to get 7.75t direct to GEO.

That's competitive or better with Atlas V in terms of mass injected, and much better in terms of cost, with a basic cost < $100M according to the data above.

For even higher delta-V, at some point the higher ISP of hydrogen may win the battle.  But FH can apply still more brute force, by expending all cores, and still would cheap compared to (for example) DIVH. 

Don't underestimate brute force as a solution.  Conceptually it can never fail (you can fail to apply enough of it, but the technique itself cannot fail).

EDIT:  Oops, made two mistakes in the above calculation.  First, the mass ratio should be exp(-1800/348/9.8 ) = 0.59, somewhat worse.  On the other hand if FH can put 20t into GTO, then the initial mass of the stack is 25t, since it includes the second stage.   The errors are of opposite sign, with the balance in favor of the FH, which can now deliver about 9t to GEO.
« Last Edit: 04/24/2018 07:40 pm by LouScheffer »

Offline RoboGoofers

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #598 on: 04/24/2018 05:32 pm »
Since Europa Clipper isn't designed yet, it could still be configured to launch on 2 FHs in 2 parts: probe and propulsion.

It won't be, but i just wanted to point out how poor a solution SLS is for the cost.
« Last Edit: 04/24/2018 05:55 pm by RoboGoofers »

Offline Comga

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Re: SpaceX Falcon Heavy Discussion (Thread 6)
« Reply #599 on: 04/24/2018 05:39 pm »
Quote from Chris' latest SLS article today (bolding mine).

Quote from: Chris Bergen
Block 1 performance capability for Europa Clipper may push the launch vehicle discussion into an uncomfortable debate, where SpaceX’s Falcon Heavy could force NASA’s hand based on the gulf of vehicle costs.  A brand-new Falcon Heavy for a high priority science mission would cost just over $100 million, whereas the latest estimates for SLS put the per-mission cost anywhere between $500 million (from NASA in 2013) to a range between $1.5 – $2.5 billion (conservative industry estimates in December 2017).

Quite a difference in LV cost. With continued SLS delays and such a lower cost for FH, SpaceX's chances for launching Europa Clipper on FH just got better. Who knows, she could even go up on BFR.

The thing is, NASA could very likely fund the development of a cryogenic Raptor upper stage for Falcon 9/Heavy and still get  Clipper to Europa faster and several times cheaper than SLS w/ ICPS.

No, just stop.

Woods170 already took care of that for you, Jim
[Jim]
Stop daydreaming.
[/Jim]
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

 

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