Author Topic: Falcon Heavy Test Flight  (Read 8581 times)

Offline Zakalwe

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Re: Falcon Heavy Test Flight
« Reply #90 on: April 14, 2019, 07:34:31 AM »
Unlike this stunt, Apollo 13 was actually inspiring

A stunt? Really?

Its sad that you feel that way.

Would you have preferred they launch a slab of concrete instead, or perhaps risk someone's multi-million dollar satellite on a test flight that could have blown up on the launch pad?

Yes, because it would have actually done something useful. SpaceX/Musk had at least years to develop a useful payload.  There are many possibilities.  Is launching a car really the best they could have come with?

There have been 20 first launches in the past 30 years.  Only one (Angara) carried a mass simulator.  The rest, with the exception of the car stunt, carried useful functioning - satellites (Delta 2, Pegasus,  PLSV, Minotaur C, H-2, Ariane 5, GLSV, Delta IV,  KZ 1, F-1,  Long March 5, Electron, ZQ-1, OS-1B ), boilerplate spacecraft (F-5), or both (Antares, LM-5).  Even the previous first SpaceX launches carried useful payloads.

Of the 20 launches seven (35%) were failures.  This did not stop the launching entities maximising the launch opportunities

Sense of humour failure alert.
Lighten up...it was most definitely a stunt, and an epic one at that. Thankfully not everything in life has to be worthy all the time.
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Offline smartcooky

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Re: Falcon Heavy Test Flight
« Reply #91 on: April 14, 2019, 08:08:22 AM »
You can think what you like of it, but when a rich narcissist builds the world's largest rocket and then, after 13 years or more to prepare for it, all he puts into orbit is a surplus car then yes, I call it a stunt.

Oh, I get it now. You're a Musk hater... and that's OK, he's not everyone's cup of tea.

Frankly, I think he has done more to advance rocket science in the last 13 years than any person, group or entity has in the last 50...

is anyone else bringing 90% of their launch hardware back and reusing it?
has anyone else reduced the cost per kg to LEO by over 60%

There have been 20 first launches in the past 30 years.  Only one (Angara) carried a mass simulator.  The rest, with the exception of the car stunt, carried useful functioning - satellites (Delta 2, Pegasus,  PLSV, Minotaur C, H-2, Ariane 5, GLSV, Delta IV,  KZ 1, F-1,  Long March 5, Electron, ZQ-1, OS-1B ), boilerplate spacecraft (F-5), or both (Antares, LM-5).  Even the previous first SpaceX launches carried useful payloads.

Of the 20 launches seven (35%) were failures.  This did not stop the launching entities maximising the launch opportunities

That is a one in three chance of losing my multi-million dollar satellite.

Thanks, but no thanks Mr Musk, I'll have you launch mine on one of your standard Falcon 9FT's - I find their 97% success rate more appealing.


Now moving right along...

A quick question about the booster separation, please.

How are the boosters connected to the core stage, and how does separation occur? The reason I ask is that, watching the video, the separation process seems to take about two seconds. Initially the boosters seemed to push upwards relative to the core stage for about a second, pause, and then peel away.

Is that what happened or did my eyes deceive me?

SpaceX doesn't like using pyrotechnics for this sort of thing, because of the potential for damage and debris.

AIUI, they use pneumatic pushers to separate the boosters. The top set of latches release first and the pushers push the top of the booster so that they tilt away from the centre core, then the bottom latches & pushers are activated. Even though there is very little air at the booster separation altitude, the whole spacecraft is cracking along at about 6,000 km/h, so there is sufficient aerodynamic force to help push the booster away.

I think is a bit of an optical illusion that the boosters appear to come forwards.

If you go to this video, press pause, advance to exactly 24:30, click on the little gear icon and set the speed to .25 you can watch the separation in slo-mo.

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Offline bknight

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Re: Falcon Heavy Test Flight
« Reply #92 on: April 14, 2019, 10:25:41 AM »
I assume the stage is kept fully pressurized, since it still has to perform an landing burn. But even with the entry burn, you do see a lot of shaking as the stage falls into the lower atmosphere.

While the stage may be pressurized there is a separate tankage system for the reentry burns.

https://forum.cosmoquest.org/showthread.php?149827-SpaceX/page56
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Offline Apollo 957

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Re: Falcon Heavy Test Flight
« Reply #93 on: April 15, 2019, 09:43:24 AM »
In amongst all the other amateur video of the recent launch/landing, I came across this one from a couple of pilots who flew just outside the "no-fly" zone in order to capture it ...


Offline gillianren

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Re: Falcon Heavy Test Flight
« Reply #94 on: April 15, 2019, 11:20:03 AM »
Gosh, what could there possibly be to hate about Elon Musk?
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Offline jfb

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Re: Falcon Heavy Test Flight
« Reply #95 on: April 15, 2019, 05:11:34 PM »
Gosh, what could there possibly be to hate about Elon Musk?

Narcissistic, thin-skinned, mercurial - basically a modern Howard Hughes in all the good and bad ways.  Tesla is successfully building and selling cars, but more often than not they're in the news because Elon has no filter between his brain and Twitter account.  He got on the wrong side of the SEC over a freaking weed joke (that just happened to move the stock price). 

Of course, the other major issue with Tesla is that they're applying the Silly Valley mentality (move fast, break things, fake it 'til you make it, go public before anyone looks too closely) to auto manufacturing, which has over a century's worth of inertia (and hard-won wisdom) behind it, so there's already some friction just in how the cars are being built.  Then you have a car company acting more like a software company in how they build and sell their product, which has everyone on their heels. 

I'm convinced SpaceX does so well precisely because Elon's not the CEO.  Gwynne runs the show day-to-day, while Elon sets the overall vision.  He needs an equivalent at Tesla. 

Offline ka9q

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Re: Falcon Heavy Test Flight
« Reply #96 on: April 15, 2019, 05:30:02 PM »
I agree it was largely a stunt, though admittedly a fun one. (Seeing the escape burn from San Diego was certainly memorable.) But this test launch could have carried a substantial payload into a useful earth orbit, and that would have been very appealing to a lot of spacecraft operators even though it was a first launch. I know AMSAT would have gladly taken the risk.

Musk repeatedly said that the Tesla would go to Mars, but it became obvious to me that wouldn't be the case. First, there was no provision to decelerate into Mars orbit, so at most it would be a flyby. Then I noticed that the 2018 Mars launch window wouldn't open for another few months, which meant it couldn't go anywhere near Mars.  But Musk was obviously determined to do an escape trajectory,  and that was definitely much less interesting. I'm not even sure I'd have found a use for a random 1 x 1.5 AU solar orbit.

Offline ka9q

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Re: Falcon Heavy Test Flight
« Reply #97 on: April 15, 2019, 05:47:04 PM »
Oh, I get it now. You're a Musk hater... and that's OK, he's not everyone's cup of tea.

Frankly, I think he has done more to advance rocket science in the last 13 years than any person, group or entity has in the last 50...
He certainly has pushed both rocket and EV technology more than anyone recently. But my opinion of Musk has gone down in the past year or so. I really wish the guy would take a vacation. He needs one.

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That is a one in three chance of losing my multi-million dollar satellite.

Thanks, but no thanks Mr Musk, I'll have you launch mine on one of your standard Falcon 9FT's - I find their 97% success rate more appealing.
Do you know how much launches normally cost? A free launch significantly affects the economics for all but the most expensive spacecraft.
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SpaceX doesn't like using pyrotechnics for this sort of thing, because of the potential for damage and debris.
Pyros are pretty reliable and safe in practice. I think one reason SpaceX avoids them is to simplify launch preparations. Once stuff like hypergolic fuels and pyros are on a spacecraft or launch vehicle, safety and access rules become very strict and can really slow down operations.


Offline AtomicDog

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Re: Falcon Heavy Test Flight
« Reply #98 on: April 15, 2019, 09:29:40 PM »
What Elon Musk has done, or has enabled to be done, has earned my undying respect.
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Offline gillianren

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Re: Falcon Heavy Test Flight
« Reply #99 on: April 16, 2019, 11:05:03 AM »
Gosh, what could there possibly be to hate about Elon Musk?

Narcissistic, thin-skinned, mercurial - basically a modern Howard Hughes in all the good and bad ways.  Tesla is successfully building and selling cars, but more often than not they're in the news because Elon has no filter between his brain and Twitter account.  He got on the wrong side of the SEC over a freaking weed joke (that just happened to move the stock price). 

Not to mention his pretty awful mistreatment of his employees that he wants people to just not talk about.
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Offline AtomicDog

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Re: Falcon Heavy Test Flight
« Reply #100 on: April 16, 2019, 01:44:27 PM »
Gosh, what could there possibly be to hate about Elon Musk?

Nothing.
"There is no belief, however foolish, that will not gather its faithful adherents who will defend it to the death." - Isaac Asimov

Offline smartcooky

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Re: Falcon Heavy Test Flight
« Reply #101 on: April 16, 2019, 03:01:20 PM »
Back on topic, r/space have reported that the centre core was lost over the side during heavy seas (8m swells). Apparently, the this octo-grabber robot thingy they use to anchor the core to the deck of the drone ship does not work with a centre core due to the extensive structure modifications required to use a F9 core as the centre of FH.

Unfortunate.
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Offline Zakalwe

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Re: Falcon Heavy Test Flight
« Reply #102 on: April 16, 2019, 03:21:49 PM »
Back on topic, r/space have reported that the centre core was lost over the side during heavy seas (8m swells). Apparently, the this octo-grabber robot thingy they use to anchor the core to the deck of the drone ship does not work with a centre core due to the extensive structure modifications required to use a F9 core as the centre of FH.

Unfortunate.

I saw that. What a shame to survive a 10,000Km/h re-entry, to find a tiny drone ship in the middle of the Atlantic, land on it and then to lose it due to heavy seas.

You would think that they would have planned a way to secure it...didnt they used to weld the footpads to the deck? Mind you, with 8 metre swells I'm not too sure that i'd fancy working to weld a 30 metre column to a deck especially if it was sliding all over the shop!
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Offline Glom

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Re: Falcon Heavy Test Flight
« Reply #103 on: April 16, 2019, 04:05:25 PM »
It's proof that the sea is above all the most hostile.

Maybe a black hole is worse.

Offline jfb

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Re: Falcon Heavy Test Flight
« Reply #104 on: April 16, 2019, 04:22:26 PM »
Unlike this stunt, Apollo 13 was actually inspiring

A stunt? Really?

Its sad that you feel that way.

It's more sad that people idolise point less stunts

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Plus, the huge amount of publicity has helped inspire a lot of young people to think about their futures as being in space, science and technology, which is definitely a good outcome, whatever you might think about the "stunt" aspect of launching a car.

It seems to have worn off.  People are more inspired by actual achievements.

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(Anyway, I thought it was cool and fun  :D )

You can think what you like of it, but when a rich narcissist builds the world's largest rocket and then, after 13 years or more to prepare for it, all he puts into orbit is a surplus car then yes, I call it a stunt.
This was a test flight.  There was a non-zero chance that it would fail to leave the pad.  Up to that point nobody'd managed to successfully launch something with that many engines, and it was SpaceX's first flight with a multi-booster vehicle.  Nobody was 100% certain they'd got the aero modeling right, nobody was 100% certain booster separation would work properly, etc. 

Being a test flight, they weren't going to risk a paying customer's very expensive bird, so they needed a mass simulator.  It could have been a concrete block or another boilerplate Dragon carrying a wheel of cheese like the first COTS demo flight, but Elon's roadster with Starman was too good a gag to pass up. 

Cheap PR, sure, but not pointless