Author Topic: Developing the BFS - Phase 1 Big Falcon Hopper (BFH) Discussion - THREAD 2  (Read 535003 times)

Offline Lars-J

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This video shows more clearly that this FH booster touches down at ~1-2 m/s. Thankfully the compressed Helium in the legs damps that out in the subsequent bounce. If it were perfectly rigid all that energy would be absorbed by structure (as depicted on left). So I think we can be confident the hopper will have *some* means of damping landing loads. I imagine we'll see soon enough.

The compressed helium in the legs doesn't have anything to do with that, the leg segments are locked and don't move at all anymore once the legs are extended. Apart from the crushable elements in the last segment any "bounce" is coming out of elasticity in the legs itself or the tank they're connected to.

No, I'm not sure that's right. The "crush cores" are just there to absorb excessive landing force. (see notes about hard landings in the past where they noted that the crush cores in the legs were used up) There does appear to be a hydraulic or pneumatic shock absorption for the F9 legs.
« Last Edit: 01/08/2019 08:38 pm by Lars-J »

Offline ThereIWas3

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It will be interesting to find out the explanation for the shiny cladding added to the base section.  Just for appearances to match the rest?  The shiny part is clearly not structural.  Will the final SS be layered like this?  Can we tell how thick the cladding is?


Offline launchwatcher

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Yes, the pad GSE would be minimal for BFH, but the LNG and LOX tanks do need to be moved to the launch site, set on some sort of foundation, with the truck unloading facilities and BFH fueling lines installed. This is all vacuum insulated piping with cryogenic valves and safety interlock instrumentation. If it were installed today it could take a month to go through commissioning, de-bugging, and dry runs before BFH test flights. And there is still items 1, 3, 4, 5, etc from above to get done.
Think about how to compress the schedule.

If their test plan is similar to the plan for Grasshopper, the first few flights won't last very long or go very high - they won't need the full tank capacity right away   A couple tanker trucks will will do for those tests.   If things go badly wrong the resulting kaboom will be smaller and it will be easier to find all the pieces, knock out a few dents and refly it.

Full-scale fuelling infrastructure can be built in parallel with the first few flights.

Offline JonathanD

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Is it possible they are doing first few flights from where it sits now?

Offline AC in NC

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Based on Bocachicagal's latest photo clearly showing two layers of metal (one dull, one shiny), where do I collect my prize? ;)

Based on no rivets and no dull layer under the TFH upper section, you don't.   ::)

Some questions answered, the nose is stacked on top of the base!

Offline glennfish

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Is it possible they are doing first few flights from where it sits now?

If they take the tent down first, yes.

Offline Lars-J

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Is it possible they are doing first few flights from where it sits now?

VERY unlikely. Too close to residences and other buildings.

Offline Restless

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Yes, the pad GSE would be minimal for BFH, but the LNG and LOX tanks do need to be moved to the launch site, set on some sort of foundation, with the truck unloading facilities and BFH fueling lines installed. This is all vacuum insulated piping with cryogenic valves and safety interlock instrumentation. If it were installed today it could take a month to go through commissioning, de-bugging, and dry runs before BFH test flights. And there is still items 1, 3, 4, 5, etc from above to get done.
Think about how to compress the schedule.

If their test plan is similar to the plan for Grasshopper, the first few flights won't last very long or go very high - they won't need the full tank capacity right away   A couple tanker trucks will will do for those tests.   If things go badly wrong the resulting kaboom will be smaller and it will be easier to find all the pieces, knock out a few dents and refly it.

Full-scale fuelling infrastructure can be built in parallel with the first few flights.

Well, I guess we'll have to see how it all works out - seat of the pants or proper space launch approach.

Offline DistantTemple

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Fire/lift from current location. No chance!

Safety and exclusion zone - close to boca Chia village. !!!
Not consistent with the plans in the EIS etc!

So as an outsider, with no knowledge of how these work.... it sounds impossible from a regulation and safety pov. to fire or hop from where it was built.

But with the current tempo, the hat has to come off so the tank dome (and what else?) can be fitted. The move to the official pad should be easy. A good slab of concrete as a (flat) initial pad could be fairly quick, and temporary partial fuelling arrangements using tanks on lorries is conceivable. ! Will a very small hop - like 10 feet be done before Dragon 2 flies - probably late Feb due to p*l***cs! ?
« Last Edit: 01/08/2019 09:41 pm by DistantTemple »
We can always grow new new dendrites. Reach out and make connections and your world will burst with new insights. Then repose in consciousness.

Fire/lift from current location. No chance!

Safety and exclusion zone - close to boca Chia village. !!!
Not consistent with the plans in the EIS etc!

So as an outsider, with no knowledge of how these work.... it sounds impossible from a regulation and safety pov. to fire or hop from where it was built.

But with the current tempo, the hat has to come off so the tank dome (and what else?) can be fitted. The move to the official pad should be easy. A good slab of concrete as a (flat) initial pad could be fairly quick, and temporary partial fuelling arrangements using tanks on lorries is conceivable. ! Will a very small hop - like 10 feet be done before Dragon 2 flies - probably late Feb due to p*l***cs! ?
You could be right? Most of the guesses from folks on this site have been wrong, including mine! I've been

involved in many projects and from experience, I'll say they'll have to step on it to meet your timetable!

Offline MTom

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What I don't understand: the whole surface is (more or less) ready, but this vertical line is like a long opening between the two half part. What could it be?

Offline zhangmdev

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What I don't understand: the whole surface is (more or less) ready, but this vertical line is like a long opening between the two half part. What could it be?

That dark vertical line is reflection of the crane, I think.

Offline Kenp51d

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Might be a reflection artifact, maybe of the lefting boom.

Ken

Offline MTom

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another part of the opening/reflection.

Offline zhangmdev

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another part of the opening/reflection.

Check the latest photo

https://forum.nasaspaceflight.com/index.php?topic=47120.msg1898584

You can see the yellow part of the crane in the reflection.

Anyway, is there anyone think proportionally the hopper is more visually appealing than the "real" spaceship? Or just me?
« Last Edit: 01/08/2019 10:19 pm by zhangmdev »

Offline freddo411

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another part of the opening/reflection.


 anyone think proportionally the hopper is more visually appealing than the "real" spaceship? Or just me?


I like the dimensions a lot.  It's beautiful.

The wrinkling of the SS skin is off putting to me at first.   I wonder if the actual starship will have visual oddities or not.   Atlas didn't have wrinkles, but it also wasn't so shiny.   https://commons.wikimedia.org/wiki/File:LOC-63C-1556.jpg

Offline FutureMartian97

It was together and now it is back apart!

I wonder if it was just a fit check?

Offline DistantTemple

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another part of the opening/reflection.
Maybe there is some final adjustment, or tightening planned along this open seam. When that has been done then the stainless sheet can be finished off like it is around the rest of the diameter. This makes a little sense, where it fits ofer the rigid "watertank" But ISTM there is no reason to take the join to the top!. However if there is 10s of cm  adjustment in the circumference, then the seam would have to go to the top or distortions would show.
We can always grow new new dendrites. Reach out and make connections and your world will burst with new insights. Then repose in consciousness.

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