Author Topic: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)  (Read 26243 times)

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 10195
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 7062
  • Likes Given: 4832
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #100 on: 07/27/2018 05:45 PM »
The salts in the brine may be of some use as well. Maybe not the most abundant ones but the rarer...
"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 TomH

  • Senior Member
  • *****
  • Posts: 2194
  • Vancouver, WA
  • Liked: 896
  • Likes Given: 297
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #101 on: 07/27/2018 06:56 PM »
At the same time, this exposes the equipment to the catalytic effects of corrosion from all those salts (assuming enough Oxygen is present for oxidation to occur), adding to the complexity of the whole enterprise.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 28186
  • Minnesota
  • Liked: 7986
  • Likes Given: 5331
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #102 on: 07/28/2018 01:05 AM »

I think Blackmore is just having a laugh.  The lake is 1.5km below the surface. It not suitable for ISRU and local science is going to be years down the line from the first human mission.
Agreed. You have to melt about enough water to fill an entire BFS just to reach the lake.
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 M.E.T.

  • Full Member
  • ****
  • Posts: 572
  • Liked: 240
  • Likes Given: 18
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #103 on: 07/28/2018 03:47 AM »
I didn’t read Blackmore’s comment as linked to the location of the Mars polar lake discovery. Rather, it was a reference to the timing of the announcement.

It seems to suggest that unbeknownst to us, SpaceX has just embarked on some major work on BFR landing R&D. And Lars was therefore jokingly saying that the announcement of the discovery of the lake makes the timing of this new phase of work feel even more meaningful.

We all know that a polar site for the initial Mars base is not a serious option, so his comment was almost certainly not a reference to the location of the lake or actual polar landings. Rather, the discovery of one  lake opens the possibility of more bodies of water existing all over the planet. Reaffirming the importance of work on BFR landing technology (which happens to be Lars ‘s area of focus).

Offline moreno7798



This is why Musk wanted to get rid of the F9 style landing legs for the BFR. It's a time consuming process. The Mars version of the BFR will probably have retractable legs which should be easier to manage.
« Last Edit: 07/29/2018 04:56 PM by moreno7798 »

Offline speedevil

  • Senior Member
  • *****
  • Posts: 2307
  • Fife
  • Liked: 1146
  • Likes Given: 1282
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #105 on: 07/30/2018 11:57 AM »
This is why Musk wanted to get rid of the F9 style landing legs for the BFR. It's a time consuming process. The Mars version of the BFR will probably have retractable legs which should be easier to manage.
It's not due to time or difficulty.

This is a particular implementation of leg, which does not have power to be able to retract the legs.
And for obvious reasons, they latch in place, because there is no reason to not have them latch in place, because of the first reason.

Hardware to pull the legs back up would not be a very large addition, and could in principle do it in several seconds before the drag became a problem.

BFS however will need to reenter, meaning at least a couple of the legs are facing orbital reentry, and make the surface non-smooth, doing all sorts of hideous things to the shock waves and heat impingement on them and the body.

Offline moreno7798

This is why Musk wanted to get rid of the F9 style landing legs for the BFR. It's a time consuming process. The Mars version of the BFR will probably have retractable legs which should be easier to manage.
It's not due to time or difficulty.

This is a particular implementation of leg, which does not have power to be able to retract the legs.
And for obvious reasons, they latch in place, because there is no reason to not have them latch in place, because of the first reason.

Hardware to pull the legs back up would not be a very large addition, and could in principle do it in several seconds before the drag became a problem.

BFS however will need to reenter, meaning at least a couple of the legs are facing orbital reentry, and make the surface non-smooth, doing all sorts of hideous things to the shock waves and heat impingement on them and the body.

It probably is not a large addition to put in retractable hardware but to me folding legs are a lesser design than having legs that would deploy in a perpendicular fashion. Don't know if BFR's design would allow it though.


Sent from my iPhone using Tapatalk

Online sanman

  • Senior Member
  • *****
  • Posts: 4193
  • Liked: 594
  • Likes Given: 8
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #107 on: 08/12/2018 10:35 PM »
If the revised scaled-back IAC2017 version of BFR is a success, then could the original bigger IAC2016 version of BFR make a comeback? Shouldn't bigger be better, in the long run?

Offline groundbound

  • Full Member
  • **
  • Posts: 200
  • Liked: 159
  • Likes Given: 8
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #108 on: 08/13/2018 02:09 AM »
If the revised scaled-back IAC2017 version of BFR is a success, then could the original bigger IAC2016 version of BFR make a comeback? Shouldn't bigger be better, in the long run?

Not if it requires exotic launch sites and also has lower profit margins for the revenue generating missions. The IAC2017 version is already larger than it needs to be for virtually all known paying customers.

Online sanman

  • Senior Member
  • *****
  • Posts: 4193
  • Liked: 594
  • Likes Given: 8
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #109 on: 08/13/2018 04:16 AM »
Not if it requires exotic launch sites and also has lower profit margins for the revenue generating missions. The IAC2017 version is already larger than it needs to be for virtually all known paying customers.

And yet its main purpose/focus is supposed to be Mars, for which the paying customers aren't quite known yet, but presumably economies of scale still apply. Otherwise, F9R and FalconHeavy are more than adequate for all existing known paying customers.

If BFR is able to fulfill its raison d'etre / business case in delivering materiel & people to Mars, what would hold back Musk from upsizing it even further, even if only just to the slightly larger IAC2016 version?

I remember that Dr Zubrin had specific criticisms of the IAC2016 version, which he felt were somewhat mitigated in the refinements for the IAC2017 version. But all of that may be predicated on the fragility of the whole Mars enterprise requiring some maximalist optimization.  At some point, if Mars travel begins to ramp up and more capital is forthcoming, then why wouldn't the "bigger is better" and the "faster is better" compulsions take hold? The more you can transport, the faster you can build up your martian beach-head.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 7483
  • Everyplaceelse
  • Liked: 1133
  • Likes Given: 7558
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #110 on: 08/13/2018 07:02 AM »
If BFR is able to fulfill its raison d'etre / business case in delivering materiel & people to Mars, what would hold back Musk from upsizing it even further, even if only just to the slightly larger IAC2016 version?
The same thing that got it downsized in the first place.

The launch pads.

Going much above the 9m size means a root-and-branch rebuild of the Canaveral sites. Much more extensive than the changes to covert from F9 to F9H.

That imposes both a significant cost and a time penalty.

If they build launch sites in Texas then they will be likely clean sheet affairs, but again the bigger LV, the bigger the exclusion zone around it.  Before long that's at the boundary of the nearest town.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline speedevil

  • Senior Member
  • *****
  • Posts: 2307
  • Fife
  • Liked: 1146
  • Likes Given: 1282
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #111 on: 08/13/2018 09:20 AM »
At some point, if Mars travel begins to ramp up and more capital is forthcoming, then why wouldn't the "bigger is better" and the "faster is better" compulsions take hold? The more you can transport, the faster you can build up your martian beach-head.

If point to point is actually gotten working, and massive consumer transport is a thing, it is plausible to get a hundred thousand tons into orbit for around $1B cost to SpaceX per synod.

(over a dozen BFS flying twice a day, 'cheaper than long haul economy' - packing them in)

Remember the BFS costs $1000/kg to buy.
You really don't want to be sending those to Mars as your primary cargo transport, if your Mars supplies are being lifted at under $10/kg.
Making that number $500/kg by growing the BFS is not going to help.

Even absent P2P, and sticking to $5M/launch ($33/kg) you need to run BFS for decades to Mars to get the production cost to amortise out - and inflation means it never will.

Most cargo needs to go to Mars some other way than inside an expensive spaceship.
Crew has arguments for remaining aboard, at least in the near term.


Offline dark55star55

  • Member
  • Posts: 3
  • Liked: 4
  • Likes Given: 0
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #112 on: 08/13/2018 01:36 PM »
https://spacenews.com/air-force-close-to-selecting-next-generation-launch-vehicles/

So the Air Force is holding a competition in which two contracts will be handed out to two winners for the development of nextgen launch vehicles and SpaceX is one of the entrants. Phase 1 of the competition chose four entities, of which SpaceX was one of them. Phase 2 will downselect from 4 to 3 and is supposed to be announced this month. I'm wondering how much funding is SpaceX poised to get if they win, billions? Since there are two contracts the Air Force wishes to award I'm almost certain SpaceX is will get this contract.

Also this news seems to have been overlooked by most which absolutely boggles my mind because ever since I read this news article it's all I can think about. The Air force's budget is north of 150 billion dollars per year, so if they choose to fund the BFR then that's it, that means this thing's gonna actually get built in our lifetime!


Offline envy887

  • Senior Member
  • *****
  • Posts: 4346
  • Liked: 2301
  • Likes Given: 1319
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #113 on: 08/13/2018 01:38 PM »
If BFR is able to fulfill its raison d'etre / business case in delivering materiel & people to Mars, what would hold back Musk from upsizing it even further, even if only just to the slightly larger IAC2016 version?
The same thing that got it downsized in the first place.

The launch pads.

Going much above the 9m size means a root-and-branch rebuild of the Canaveral sites. Much more extensive than the changes to covert from F9 to F9H.

That imposes both a significant cost and a time penalty.

If they build launch sites in Texas then they will be likely clean sheet affairs, but again the bigger LV, the bigger the exclusion zone around it.  Before long that's at the boundary of the nearest town.

Even the smaller BFR is likely going to have to go offshore to hit any high launch rate. Once they go offshore, exclusion zones are much less limiting.

Offline dark55star55

  • Member
  • Posts: 3
  • Liked: 4
  • Likes Given: 0
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #114 on: 08/13/2018 02:28 PM »
Boy I can't stop thinking about this and if you read on you'll see why.

https://spacenews.com/air-force-stakes-future-on-privately-funded-launch-vehicles-will-the-gamble-pay-off/

So the Air Force is holding a COTS like competition for the development of nextgen launch vehicles, 4 winners were chosen for phase 1, phase 1 simply gave money out for the development of rocket engines, 3 winners will be chosen for phase 2 and money will be handed out so they can build launch system "prototypes", finally only 2 winners will be chosen for phase 3 at which point contracts will be handed out.

Ok so phase 2 winners will hopefully be announced this month but what really keeps me up at night thinking about this is the use of the word "prototypes", what prototype is SpaceX going to build, the Falcon Heavy? No, this must be for the BFR/BFS, it all makes sense when you think about it, SpaceX is already building the BFS for testing as soon as next year. Can it get anymore obvious? The Air Force is going to fund the BFR!

Offline su27k

  • Full Member
  • ****
  • Posts: 1042
  • Liked: 767
  • Likes Given: 71
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #115 on: 08/13/2018 04:08 PM »
Boy I can't stop thinking about this and if you read on you'll see why.

https://spacenews.com/air-force-stakes-future-on-privately-funded-launch-vehicles-will-the-gamble-pay-off/

So the Air Force is holding a COTS like competition for the development of nextgen launch vehicles, 4 winners were chosen for phase 1, phase 1 simply gave money out for the development of rocket engines, 3 winners will be chosen for phase 2 and money will be handed out so they can build launch system "prototypes", finally only 2 winners will be chosen for phase 3 at which point contracts will be handed out.

Ok so phase 2 winners will hopefully be announced this month but what really keeps me up at night thinking about this is the use of the word "prototypes", what prototype is SpaceX going to build, the Falcon Heavy? No, this must be for the BFR/BFS, it all makes sense when you think about it, SpaceX is already building the BFS for testing as soon as next year. Can it get anymore obvious? The Air Force is going to fund the BFR!

I think the forum is divided on this, some of us agree with you that bidding F9/FH as "prototype" makes no sense, but others think BFR is too ambitious for Air Force and SpaceX will play it safe so to speak, I guess we'll know soon enough.

One thing though, while Air Force is flush with money, I believe this particular competition only has $2B or so funding, and it will be divided 2 to 3 ways. Certainly a substantial mount, but no where near enough to cover everything.
« Last Edit: 08/13/2018 04:12 PM by su27k »

Offline speedevil

  • Senior Member
  • *****
  • Posts: 2307
  • Fife
  • Liked: 1146
  • Likes Given: 1282
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #116 on: 08/13/2018 06:02 PM »
I think the forum is divided on this, some of us agree with you that bidding F9/FH as "prototype" makes no sense, but others think BFR is too ambitious for Air Force and SpaceX will play it safe so to speak, I guess we'll know soon enough.

An upgraded FH might sort of make sense from a SpaceX perspective.

FH, with stretched S2 would enable:
* Easier reuse of middle core on heavier payloads, and 'trivial' recovery of S2.  (Post 6 ton or so injection of a satellite into GTO, entry burn to come in at 3km/s).
* Operational flexibility for delivery of really large customer payloads to GEO.
* Get payload designers designing for payloads that can be switched to BFR.
* Avoid the risk of others catching up by continuing to develop the falcon in case BFR is extensively delayed.
* Throw a lot at Mars in 2020.







Offline niwax

  • Full Member
  • *
  • Posts: 141
  • Germany
  • Liked: 74
  • Likes Given: 16
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #117 on: 08/13/2018 07:19 PM »
I think the forum is divided on this, some of us agree with you that bidding F9/FH as "prototype" makes no sense, but others think BFR is too ambitious for Air Force and SpaceX will play it safe so to speak, I guess we'll know soon enough.

An upgraded FH might sort of make sense from a SpaceX perspective.

FH, with stretched S2 would enable:
* Easier reuse of middle core on heavier payloads, and 'trivial' recovery of S2.  (Post 6 ton or so injection of a satellite into GTO, entry burn to come in at 3km/s).
* Operational flexibility for delivery of really large customer payloads to GEO.
* Get payload designers designing for payloads that can be switched to BFR.
* Avoid the risk of others catching up by continuing to develop the falcon in case BFR is extensively delayed.
* Throw a lot at Mars in 2020.


You are half a post away from the forbidden word, "Raptor upper stage".

But seriously, I expect this to be mostly furthering F9/FH certification. Remember they only got FH Air Force certification a few weeks ago, maybe they'll work on streamlining the processes around that.

Offline TripleSeven

  • Full Member
  • **
  • Posts: 280
  • Istanbul turkey
  • Liked: 123
  • Likes Given: 504
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #118 on: 08/13/2018 07:55 PM »
I think the forum is divided on this, some of us agree with you that bidding F9/FH as "prototype" makes no sense, but others think BFR is too ambitious for Air Force and SpaceX will play it safe so to speak, I guess we'll know soon enough.

An upgraded FH might sort of make sense from a SpaceX perspective.

FH, with stretched S2 would enable:
* Easier reuse of middle core on heavier payloads, and 'trivial' recovery of S2.  (Post 6 ton or so injection of a satellite into GTO, entry burn to come in at 3km/s).
* Operational flexibility for delivery of really large customer payloads to GEO.
* Get payload designers designing for payloads that can be switched to BFR.
* Avoid the risk of others catching up by continuing to develop the falcon in case BFR is extensively delayed.
* Throw a lot at Mars in 2020.

 a methane upper stage...nothing will happen on Mars in 2020...sorry

Offline su27k

  • Full Member
  • ****
  • Posts: 1042
  • Liked: 767
  • Likes Given: 71
Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 4 (Post Speech)
« Reply #119 on: 08/14/2018 01:48 AM »
I think the forum is divided on this, some of us agree with you that bidding F9/FH as "prototype" makes no sense, but others think BFR is too ambitious for Air Force and SpaceX will play it safe so to speak, I guess we'll know soon enough.

An upgraded FH might sort of make sense from a SpaceX perspective.

FH, with stretched S2 would enable:
* Easier reuse of middle core on heavier payloads, and 'trivial' recovery of S2.  (Post 6 ton or so injection of a satellite into GTO, entry burn to come in at 3km/s).
* Operational flexibility for delivery of really large customer payloads to GEO.
* Get payload designers designing for payloads that can be switched to BFR.
* Avoid the risk of others catching up by continuing to develop the falcon in case BFR is extensively delayed.
* Throw a lot at Mars in 2020.

The problem is these things are just on paper, currently there is no big payloads that require stretched S2, and no plan to throw things at Mars in 2020. If SpaceX continues to develop F9/FH, it needs to be something that brings in additional money which they can use to fund BFR and Starlink, a stretched S2 doesn't do that.

But I should clarify that I think SpaceX will bid F9/FH + BFR as a tag team, with BFR handling the heavy launches that requires bigger fairing. I don't think they are crazy enough to propose BFR only for everything. So they may include some F9/FH work in the proposal along with BFR, for example, vertical integration.

Tags: