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General Discussion => Polls Section => Topic started by: whitelancer64 on 11/08/2018 03:57 PM

Title: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: whitelancer64 on 11/08/2018 03:57 PM
Per the various tweets from Elon Musk that have generated much interest today:

What do you think the intent is? A true "mini-BFS" or a modified 2nd stage?

A or B?

*edit*

or C, "other" please describe :)
Title: Re: "Mini-BFS" or Modified 2nd Stage
Post by: cbarnes199 on 11/08/2018 04:01 PM
B

I think they want to use these modified second stages to launch paying customers.  So they need to be very lightly modified in order to serve their primary purpose.

Anything done to a second stage that will be ready to launch by June is not very major.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: kevinof on 11/08/2018 04:04 PM
B
An existing, slightly modifed S2 with current MVac.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: rpapo on 11/08/2018 04:08 PM
B.  That's the SpaceX way of doing things.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: nacnud on 11/08/2018 04:10 PM
B
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: lamontagne on 11/08/2018 05:04 PM
A.  Need to test the canards
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: jak Kennedy on 11/08/2018 05:10 PM
A. Although I think the diameter will match the current fairing. If really reusable the mini BFS would not have to be shipped too much.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: speedevil on 11/08/2018 05:10 PM
B).
Carbon chomper, with the maximum diameter of the current fairing. Probably with Mvac initially, but designed to go to Rvac and eventually land propulsively if things go right.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: tyrred on 11/08/2018 05:14 PM
B (C)

B Modified S2

(C) With aero surfaces "tucked" away during launch, so won't look like B quite so much
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: saliva_sweet on 11/08/2018 06:09 PM
B
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: zodiacchris on 11/08/2018 06:16 PM
B modified first stage, no payload, test vehicle only...
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Wolfram66 on 11/08/2018 06:37 PM
B (C)

B Modified S2

(C) With aero surfaces "tucked" away during launch, so won't look like B quite so much

or new fairing that encapsulates the entire mBFR S2 thus covering the aero surfaces in "Stowed configuration" like Atlas V DreamChaser[TM]
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Poole Amateur on 11/08/2018 06:51 PM
B, I believe it to be a test stage only.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Lar on 11/08/2018 07:11 PM
I have created an actual poll.

A is the first option, B the second and C the third when trying to correlate what people said in early comments to the actual poll.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Coastal Ron on 11/08/2018 07:43 PM
I chose "B" based on what Elon Musk has said. I'm thinking this won't be a product per se, but just a modification that allows them to incrementally test components for the BFS.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Darkseraph on 11/08/2018 07:47 PM
I think the third option:

I believe it will be a transitional vehicle that is not quite a mini-BFS yet (no propulsive landing, no in space refuelling) but the door will be left open to develop it into a full mini-spaceship in order to make Falcon completely reusable or in case BFR is delayed.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: HVM on 11/08/2018 08:06 PM
I am pretty sure it going to be dedicated mission just for testing re-entry, regular vac-merlin and tanks but with a heat shield and aerodynamic surfaces. And will look like A.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Kansan52 on 11/08/2018 08:26 PM
D - Shaped like A and dispenses Matchbook Teslas.

Really though. A if they announce recovery and B if only test. And the A could be a small sat dispenser even with no recovery to pay for some of the costs.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Negan on 11/08/2018 08:42 PM
I chose B because I can't understand how a 2nd stage that carries no payload could be considered an "upgrade" which is the actual purpose of the Falcon 2nd stage!

Upgrade - raise (something) to a higher standard, in particular improve (equipment or machinery) by adding or replacing components.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Doesitfloat on 11/08/2018 08:44 PM
Looking at the Manifest, Spacex has the SARah missions coming up.  Those missions were initially sold as F1 missions. They are 3 small satellites but go to different planes. That is 3 potential flights all out of Vandenburg.
Plenty of excess performance to use for this experiment.  The First part of the mission is to deliver a satellite so the payload adapter and fairing are required. Would be great if they were recovered and reused. 
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Rocket Science on 11/08/2018 10:05 PM
Voted B as part of the full reusability desire for Falcon 9...
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: Zed_Noir on 11/08/2018 10:45 PM
Pick C. Think SX will do option B first then option A if there is no hiccups.

They will have to test out the forward canards eventually. Better on a mini-BFS then a full size article.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: QuantumG on 11/08/2018 11:26 PM
I just hope they don't go for B and end up doing A. Feature creep is a project killer.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: tater on 11/08/2018 11:29 PM
They could do B, and still probably get some sort of folded canard (grid fins?) just under the fairing as well.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: hkultala on 11/09/2018 06:03 AM
C.

Both separate fairing AND the hands.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: HVM on 11/09/2018 06:57 AM
Clearly they are going to re-engineer the payload adapter and the fearing ring so they can be secured and ejected through TPS; open multiple holes to the TPS and put whole reentry test in jeopardy. In a mission with very little payload margin. And find a customer for this configuration.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: su27k on 11/09/2018 12:47 PM
C. It's a modified 2nd stage that looks like A from the outside.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: whitelancer64 on 11/09/2018 03:44 PM
Clearly they are going to re-engineer the payload adapter and the fearing ring so they can be secured and ejected through TPS; open multiple holes to the TPS and put whole reentry test in jeopardy. In a mission with very little payload margin. And find a customer for this configuration.

"Holes in TPS" has never really been a problem. The Shuttle had a similar "issue" with the ET attach points. And its landing gear.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: jongoff on 11/10/2018 09:52 PM
I voted for the second option. I think this is a modified upper stage with TPS and aerosurfaces to test some of the BFR reentry/control concepts. I wish it were a mini-BFS that had a clear path to making F9US fully-reusable, but I highly doubt it's that, especially given how short the timeframe is between now and then. I remember how crazy it was designing and building Xoie at Masten in a short time period. Trying to build a hypersonic glider system and TPS in 8 months suggests it's the first of a series of post-payload separation experiments to start learning how BFS reentry might work. Which is still awesome, even without acting like a fully reusable Falcon 9 is just around the corner.

~Jon
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: skybum on 11/11/2018 12:01 AM
A, even if it's just a test article rather than a regular-service vehicle. If they're using this thing to test the re-entry interface and hypersonic controls, it'll need to follow the BFS mold lines and mass distribution pretty closely.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: deruch on 11/15/2018 06:54 AM
B.

This is the vehicle with the shortest development cycle that answers the question, "We've already got the 2nd stage up there re-entering.  What can we do with it to start learning what we really need to know for a fully operational BFS as soon as possible?"
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: AndersofOz on 11/16/2018 01:19 AM
I have voted for B if they plan on flying with customers which was the pattern with the first stage landings.

I wonder if they might not need a better ACS in conjunction with a better way to vent residual propellant (i.e. without causing the stage to spin) in addition to the obvious TPS and fins to ensure the correct AoA on reentry.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: moreno7798 on 11/18/2018 05:23 PM
I'd say it's going to be "A". Mini-BFS test article only - no payloads, no propulsive landings - just for testing of heat shield, and atmosphere winged entry, and drag dynamics. This will be the proof of concept for Full BFS tests at Boca Chica. This will also be the backup plan in case there are major delays in Full BFS test developments. In that case, all you have to do is add the propulsive landing capability to mini BFS.
Title: Re: POLL: "Mini-BFS" or Modified 2nd Stage
Post by: smoliarm on 11/18/2018 05:48 PM
B.

As I understand Elon's tweets, the purpose is to study re-entry profile (in search for a survivable one) and control system for it. Therefore no need for "A"-type, just regular s2 plus thermal protection and control surfaces with actuators.

I also would guess that such experiment will take place on the next launch deploying Starlink