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Title: Falcon Heavy launch: Space X has an almost perfect day
Source:
HotAir
URL Source: https://hotair.com/archives/2018/02 ... -space-x-just-showing-off-now/
Published: Feb 6, 2018
Author: John Sexton
Post Date: 2018-02-06 20:09:05 by Tooconservative
Keywords: None
Views: 1284
Comments: 27
SpaceX has now successfully landed Falcon-family rockets 24 times — three on this mission alone. (The rocket family is named after another famously reusable spaceship, the fictional Millennium Falcon from “Star Wars,” Musk has said.) But perhaps the biggest draw of today’s launch was the Falcon Heavy’s unique payload: a Tesla Roadster riding atop the rocket’s second stage. Musk announced in December that the “midnight cherry red” convertible, which he owns, would be the first Falcon Heavy payload. Then, on Monday, he revealed another surprise: a spacesuit-clad mannequin called “Starman”(a reference to David Bowie’s song “Starman”) in the driver’s seat, with its right hand on the wheel and left arm resting on the door. So to sum up, Musk sent his car to mars with a “driver” named for a David Bowie song on a launch vehicle named after a Star Wars spaceship. Not a bad day if you’re a nerd who enjoys science and science fiction. The full Space X video is below, but if you only have a moment now, watch this because it’s incredible: — WESH 2 News (@WESH) February 6, 2018 Here’s what one of those boosters looked like up close after landing: A post shared by Elon Musk (@elonmusk) on Feb 6, 2018 at 3:23pm PST As mentioned above, it seems the day didn’t quite go perfectly. The Verge is reporting that the center core, which was supposed to land out at sea, did not make it. Still, Elon Musk is clearly having a very good day today and and who can blame him: — Elon Musk (@elonmusk) February 6, 2018 — Elon Musk (@elonmusk) February 6, 2018 Here’s the full Space X launch video: Poster Comment: The center core was lost trying to land on the barge. At least two of its 9 Merlin engines failed to ignite and it hit the water going 300mph. You’ve probably seen some clips of the Space X launch that took place today already but if not you really did miss something pretty spectacular. The launch was successful though it appears one of the three boosters did not land itself properly. Still, the image of the two boosters landing themselves simultaneously on adjacent landing pads seemed unreal. And then on top of that, there was the cargo for this test launch: Elon Musk’s own Tesla Roadster with “Spaceman” at the wheel (actually Space X’s own space suit design). From Space.com: Standing 23 stories tall, the Falcon Heavy rocket is SpaceX’s largest rocket yet and the most powerful booster since NASA’s mighty Saturn V moon rocket. Its first stage is powered by three core boosters based on SpaceX’s Falcon 9 rockets, with 27 engines (nine per booster) firing in unison to produce about 5 million lbs. of thrust (22,819 kilonewtons) at liftoff… And of course @SpaceX stuck the landing. #FalconHeavy https://t.co/Q9kGlU8BJL pic.twitter.com/3u0CP8wYhI Though the Falcon Heavy’s outer cores successfully landed after launch this afternoon, the middle core of SpaceX’s huge rocket missed the drone ship where it was supposed to land, a source tells The Verge. SpaceX hasn’t yet confirmed this publicly. View from SpaceX Launch Control. Apparently, there is a car in orbit around Earth. pic.twitter.com/QljN2VnL1O
. . . Currently over Australia 🇦🇺 pic.twitter.com/HAya3E6OEJ 
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Begin Trace Mode for Comment # 23.
#8. To: Tooconservative (#0)
I thoght they used only three (of the nine) engines for landing, and that two of those three failed.
We might both be right. But let's have a bloody fight about it anyway.
Just sayin'. If you're right that it take nine engines to land an empty booster, then the problem is more dificult to solve than if they only need three and can use the other six as back-up.
I didn't say that at any point. I said that at least two Merlin engines failed. To maneuver properly, the engines under thrust need to be properly spaced. You also overlook the possibility that it is designed for only particular engines to be used for landing. On launches, I've read that they can lose an engine and still make orbit. But launch is very different than landing.
Well, no. You said, "At least two of its 9 Merlin engines failed to ignite ..." (meaning 7 did?) "To maneuver properly, the engines under thrust need to be properly spaced. You also overlook the possibility that it is designed for only particular engines to be used for landing." That's all true. But if only three engines are needed for landing, the engineers have some wiggle room to come up with a redundancy solution. If all nine are needed, the solution is more complex.
It doesn't mean that at all. But you go ahead and pretend that if it makes you feel good. My guess is that they would be 3 sets of 3 engines, equally spaced. We also don't know if certain engines are designated as the landing engines. Maybe only 3 engines are ever used in the Falcon 9 landings. I have read that they do most of the deceleration using a 3-engine burn, then cut back to just a single-engine at landing. This is called the "hover-slam" because it comes down pretty fast and reduces velocity to 0 just as it touches the ground.
The central core skipped the "hover" part.
Looking further, I found better answers at Slashdot where they discussed this. These are individual nested comments, each replying to the previous.
Hard to believe that the flame from the one good engine didn't ignite the raw fuel coming out of the other two.
Well, they are coming in at 3000mph so that fuel would blow away. A live start in that much airflow would be hard. The center engine alone managed to slow it to 300mph before it hit the water. If they didn't need that starter fuel, they wouldn't use it.
I think the center core is pretty high up before it starts the engines to slow it down. Meaning there is very little air to produce a significant airlow, even at 3,000mph. But hey. I'm no rocket scientist.
That TEA-TEB is used because it combusts with cryogenic liquid oxygen. They can't restart those engines otherwise since there isn't enough oxygen to support combustion. Apparently, they just didn't have enough TEA-TEB fuel onboard to get the engines lit again. Everything about these SpaceX rockets is just-barely-enough in design, even this big-ass Falcon Heavy. It's a miracle they fly at all. Yet they have a good record compared to other launch platforms. Even the Ariane rockets or the military's big launchers don't do much better at 3-4 times the cost. No one ever talks much about our military space program but it is a huge and very costly program.
My understanding is that those engines burn kerosene and liquid oxygen. So they have oxygen. According to the launch video, the altitude at 3 minutes (MECO) was 85 km (or about 50 miles). Essentially a vacuum.
#24. To: misterwhite (#23)
At 3000mph, even a near-vacuum has significant impact. Sure, it would kill us quickly if we tried to breathe it but we aren't a rocket engine that requires a dangerous pyrophoric igniter fuel to light off the LOX that is used to keep rocket engines burning in space or near-vacuum where there isn't enough oxygen for any normal combustion. For that matter, these rockets can't get off the launch pad without carrying their own oxidizers. It's a matter of the efficiency of combustion of fuel. At a certain point, you get so much more thrust by adding oxidizer to your rocket fuel so it can fully combust and produce the insane amounts of thrust required in even launches to low-Earth orbits, let alone launches like Falcon Heavy that are capable of putting payloads on the moon or in Mars orbit or missions to other planets. I hope you don't want to have a silly discussion about the role of oxidizing agents in rocket engines. Because that's just stupid.
Top • Page Up • Full Thread • Page Down • Bottom/LatestAt least two of its 9 Merlin engines failed to ignite and it hit the water going 300mph.
#9. To: misterwhite (#8)
I thoght they used only three (of the nine) engines for landing, and that two of those three failed.
#10. To: Tooconservative (#9)
But let's have a bloody fight about it anyway.
#11. To: misterwhite (#10)
If you're right that it take nine engines to land an empty booster,
#12. To: Tooconservative (#11)
I said that at least two Merlin engines failed.
#13. To: misterwhite (#12)
Well, no. You said, "At least two of its 9 Merlin engines failed to ignite ..." (meaning 7 did?)
That's all true. But if only three engines are needed for landing, the engineers have some wiggle room to come up with a redundancy solution. If all nine are needed, the solution is more complex.
#16. To: Tooconservative (#13)
This is called the "hover-slam" because it comes down pretty fast and reduces velocity to 0 just as it touches the ground.
#18. To: misterwhite (#16)
Maybe this is as good an explanation as we'll get. They've produced 3 versions of these Merlin engines so it's sometimes hard to find info that is accurate about the current Merlin engines used on the Heavy.
#19. To: Tooconservative (#18)
#20. To: misterwhite (#19)
Hard to believe that the flame from the one good engine didn't ignite the raw fuel coming out of the other two.
Triethylaluminium ignites on contact with air and will ignite and/or decompose on contact with water, and with any other oxidizer[9]—it is one of the few substances pyrophoric enough to ignite on contact with cryogenic liquid oxygen. Its easy ignition makes it particularly desirable as a rocket engine ignitor. The SpaceX Falcon 9 rocket uses a triethylaluminium-triethylborane mixture as a first-stage ignitor.
#21. To: Tooconservative (#20)
Well, they are coming in at 3000mph so that fuel would blow away. A live start in that much airflow would be hard.
#22. To: misterwhite (#21)
(Edited)
#23. To: Tooconservative (#22)
They can't restart those engines otherwise since there isn't enough oxygen to support combustion.
Replies to Comment # 23. According to the launch video, the altitude at 3 minutes (MECO) was 85 km (or about 50 miles). Essentially a vacuum.
End Trace Mode for Comment # 23.
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