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Can't wait to see what the dummy payload would be. I'm hoping it's not just a wheel of cheese or something. My favourite possibility (although exceedingly unlikely) would be that it would be a weight-for-weight mockup of an empty Atlas V, since it could lift that and that would be the ultimate snub to ULA - "we can launch your entire rocket with our rocket" 
I would die laughing if they launched a Tesla (any hazardous components removed first). Some no-longer-needed test mule or something salvaged and non-functional, something with no real cost except to prep for launch. I wonder if Guinness would put that record down as the fastest speed achieved by a production car?
More realistically, I think it'd be neat if they launched something heavy on a Lunar or Mars transfer orbit. Not an actual mission, just something to show that they can do it.
I would die laughing if they launched a Tesla (any hazardous components removed first). Some no-longer-needed test mule or something salvaged and non-functional, something with no real cost except to prep for launch. I wonder if Guinness would put that record down as the fastest speed achieved by a production car?
More realistically, I think it'd be neat if they launched something heavy on a Lunar or Mars transfer orbit. Not an actual mission, just something to show that they can do it.
A few months ago I tweeted Elon suggesting that the first FH payload be a Model 3 release candidate car, since it is going to be crushed anyway. Burning it up on re-entry would be more dramatic.
Surprisingly, he did not tweet me back...
A great article on SpaceX, LC-39A, SLC-40, and some info on FH being worked on:
SpaceX Falcon 9 conducts static fire as Falcon Heavy waits in the wings | NASASpaceFlight.com
SpaceX Falcon 9 conducts static fire as Falcon Heavy waits in the wings | NASASpaceFlight.com
Thanks for that link, very informative article, and I loved to see the satellite photo showing the beginning of work on LZ-2! (I assume it will be called that, I could be wrong)
A few months ago I tweeted Elon suggesting that the first FH payload be a Model 3 release candidate car, since it is going to be crushed anyway. Burning it up on re-entry would be more dramatic.
Surprisingly, he did not tweet me back...
Practically speaking, the payload has to be (a) balanced and (b) strong and supported rigidly enough that it will not fall apart due to launch vibration and forces.
Hi @Grendal. Has SpaceX made public any changes to the F9 Static Firing Test procedure for Falcon Heavy?
If they plan to do a full 27 engine test, I would imagine they would need additional hold down hardware on the pad for each of the side cores. Putting triple the load on the existing ones, not to mention the attach points on the center core, would seem (to a non engineer like me) to be a bit imprudent. Any info or thoughts?
So far, each side booster and core have been test fired individually at the McGregor testing facility. The TEL (transporter-erector-launcher) is being modified for the FH and will allow for a full 27 engine static fire. Both the center booster and side boosters will have their own hold down hardware for the reason you mentioned. That modification will happen the moment that LC-40 comes on line. SLC-40 will have its own TEL separate from LC-39A. We know that OTV-5 launch will happen out of 39A but it's possible that the launch after that, SES-11 with the CRS-10 booster, could happen at SLC-40. If that happens, then we can count on a November FH launch as Elon recently said. All the boosters for FH are at the Cape and all have been tested at McGregor. The last side booster just arrived in the last day or two. So all the rocket elements are in place and it is just a matter of the infrastructure being finalized.
I have been reticent to ask what may be a stupid question. At some point in the future when reusability levels have been well established, might test burns be at least partly eliminated? They seem quite wasteful, should there not be a better way to establish readiness?
nwdiver
Well-Known Member
I'm not an expert by any stretch but my understanding of the stresses experienced during launch and re-entry mean that they almost have to rebuild the engines. The refurbished engines have to be re-certified. Any fuel 'wasted' is a rounding error compared to a $50M+ payload...
I understand. My question is that sooner or later they'd seem to want to minimize foreign stresses induced by testing.
This makes me remember two things: testing magneto function in old general aviation engines and stress testing for heart function in humans. Both of this cause significant stresses that sometimes cause new problems, so newer techniques have been devised for much of the traditional practices. Knowing exactly zero about the rocket launching businesses, it still seems to me they'd want less stress inducing stress testing, if they could have it. Thus my question.
perhaps I'm just being ignorant.
No. That is a good question. SpaceX chooses to do the static fire test burns. They are not mandatory. SpaceX has various reasons that they do choose to do them. Some of those reasons are simply to test the hardware prior to a launch, it gives their customers an assurance of success, and most importantly it gives them the ability to make a correction prior to launch. It is a bit wasteful but SpaceX and Elon think they are important.
nwdiver
Well-Known Member
If you use commercial aviation as an example they go to full thrust to take off but they have a few seconds to abort the take off if something is wrong with the engines. Is there a similar opportunity with a rocket? That would be interesting to know. I don't think I've ever seen an abort after ignition. That might be one reason they would always have a static fire test...
As a tiny difference, few commercial aircraft use full thrust for takeoff. Much lower thrust is ordinarily used so that directional control can be maintained in the even of an engine failure. After takeoff thrust is then added for climbing, then generally reduced somewhat for cruise. There are exceptions. The most striking such cases are with two engine aircraft with the engines mounted on the main wing.
Rockets do not have quite such the same circumstance, but IIRC Falcon Heavy and Falcon 9 are both designed to tolerate one or more engine failures in flight. Thrust imbalance can be dealt with quite effectively once in flight, but not so much while taking off.
Before liftoff, the nine engine are lit in a staggered order. Once they all report back that they are lit and happy, the hold downs release.
Stated goal is 24 hour turn around, so there would not a be a trip to Texas for test firing. Could still have test fire at the pad.
Actually a launch abort did happen on the pad. Here is a video of that event for SES-9:
Actually the booster that went through 9 full burns after recovery was the "heavily abused" second ASDS recovered booster JCSAT 14. It was the first booster recovered from a GTO launch. That booster became the test bed for booster abuse which has led to the Block 4 and Block 5 modifications.
Since this is a FH thread, it is important to remember that all the boosters used for the FH test are Block 3 old design boosters. The two side boosters are reused boosters including the other heavily abused Thaicom 8 GTO ASDS recovered booster. SpaceX intends to recover every one of these boosters but it will be interesting to see whether these will be reused again. There is no question that the military will demand an all new rocket for their launch. That will be the first launch of a FH after this successful test.
It will be interesting to see what SpaceX's strategy for used Block 3 and Block 4 boosters will be.
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N5329K
Active Member
This makes me remember two things: testing magneto function in old general aviation engines...
No real stress imposed by switching mags on runup in a general aviation piston engine. The stress comes when the pilot forgets to switch back to BOTH, which effectively leans the engine and results in less power available for takeoff. Depending on runway length, the pilot might not even notice this until shutting down after landing. A short field departure, hot, high and heavy, that's where the stress part comes in.
Robin
No real stress imposed by switching mags on runup in a general aviation piston engine. The stress comes when the pilot forgets to switch back to BOTH, which effectively leans the engine and results in less power available for takeoff. Depending on runway length, the pilot might not even notice this until shutting down after landing. A short field departure, hot, high and heavy, that's where the stress part comes in.
Robin
That brings back a painful memory. Luckily the takeoff happened, the flight was uneventful and I was the only one who ever knew how nearly terminally stupid I had been was me, and now you.
For all of us we can be thankful that stupidity and hubris probably aren't being combined with FH. With all those engines at once...I do want to see a takeoff.
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