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Questions tagged [falcon-9]

Questions regarding the Falcon launch vehicle developed by SpaceX for medium payloads (15,000 lbs) to LEO and GEO (via GTO, second stage cannot inject into GEO direct)

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4k views

Why does the video feed always fail during Falcon 9 landings?

I'm in love with SpaceX and Falcon 9, I watch every live stream and the most special, most amazing, most thrilling part of each launch is the 1st stage landing. Seeing the smoke (or vapor) clear and ...
3
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2answers
618 views

SpaceX second stage altitude decrease?

I was watching SpaceX's launch of the Japanese satellite JCSAT-16 yesterday, and the second stage at a point seemed to decrease in altitude (from 171km to 165km) at about T+00:07:00 in this video. Is ...
3
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1answer
437 views

When this F9 2nd stage engine suddenly moves upon shutdown, is it moving along the rocket's axis?

The GIFs are made from frames of the live broadcast of SpaceX JCSat-16 2nd stage around the time of the second engine cut-off (SECO-2). It looks like the engine moves outward axially as the thrust ...
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0answers
333 views

What makes this shadow pattern on the 2nd stage nozzle SpaceX JCSat-16?

I think it may be related to the sun, but I don't understand the "tooth" shape in the GIF - is this a shadow of something? Is the spacecraft already spinning for the satellite deployment? What are ...
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0answers
94 views

How long does it take SpaceX to mount a stage on the McGrgeor test stand, run the test, and dismount it?

Gwynne Shotwell at SmallSat 2016 in Utah mentioned that SpaceX would be using the JCSAT-14 recovered first stage as a fleet leader in wear and tear. That they would be mounting it on the McGregor, TX ...
10
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1answer
333 views

How does ITAR affect SpaceX's display of the Orbcomm first stage outside their headquarters?

There was a time, where people touring the SLC-40 facility were not allowed to take pictures of the engine end of the first stage for ITAR reasons. It appears that has relaxed since I have seen lots ...
5
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1answer
469 views

What is this 'engine plume interaction'?

SpaceX just released this high-speed footage, writing in the comments: Missions in order of appearance: May JCSAT-14; July CRS-9 launch, stage separation, engine plume interaction, and re-entry ...
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2answers
2k views

Can Falcon 9 first stage landing final burn using one, two, and three engines? Tradeoffs?

This question is about the final burn in the landing sequence of the Falcon 9 first stage return to Earth tests. If I understand correctly, there is usually far more thrust than there is weight at ...
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4answers
4k views

How does a simple construction keep a firing rocket on the ground?

Today I have seen this report of a SpaceX Falcon 9 rocket test firing. The force of a burning rocket is tremendous, and in the video we see an apparently simple construction keeping the rocket (or ...
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0answers
491 views

How is retropropulsion by the Falcon 9 first stage being used to design retropropulsion entry on Mars?

Much has been made of how the reentry burns of Falcon 9 first stages occur at an altitude where the atmosphere is similar in density to the atmosphere of Mars, and so they demonstrate that supersonic ...
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3answers
537 views

Could a Falcon 9 booster “abort” a landing, then land shortly thereafter, or somewhere nearby?

This comment below this question has me somewhat convinced that it would be hard for a Falcon 9 booster to abort a landing at the last minute (say within the last 100 meters or something like that) ...
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1answer
343 views

What happened to Formosat-4 and Formosat-6?

Formosat-5 (see also Gunters) is expected to be deployed along with Sherpa later this year. I noticed that before 5 comes 3, and after 5 comes 7. In that part of the world the number 4 is like a ...
6
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1answer
395 views

How does the flight trajectory of a GEO vs LEO mission vary for a Falcon 9 first stage?

How does the trajectory vary between the two types of missions? Specifically, how does the speed and velocity vary for the booster for a Falcon 9 mission?
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4answers
1k views

Recent Falcon 9 flights - 'topped off' with propellants, or just a margin over what's needed to land?

A simplified version of the landing choices might be - if there's going to be sufficient propellant, the plan is for the F9 first stage to u-turn and go all the way back to the launch area to land. ...
1
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1answer
109 views

What kind of maneuver Falcon9 & Dragon follows after separation

I was taking long-exposure shots of tonight's SpaceX launch and noticed these swirling like maneuvers when I zoomed-in: Are both stages making a roll or something? Separation Stage-1 Stage-2
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2answers
529 views

What is behind Dragon's Guidance, Navigation and Control bay door?

The timeline in the press kit for the upcoming CRS-9 SpaceX launch says at about 11 minutes after launch, "Dragon's solar arrays deploy", and at 2 hours 19 minutes, "Dragon's Guidance, Navigation and ...
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1answer
3k views

What's the atmospheric drag coefficient of a Falcon 9 at launch (sub-sonic, large fairing)

While I said just a few hours ago that "There's almost no such thing as a dumb question! this one just might sound like one. I'm making some slides about first principles thinking applied to ...
9
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1answer
431 views

What definition of “LEO” does SpaceX use when specifying payload capability?

Please forgive me if I am asking a dumb question. I am a little curious about the orbital parameters of "LEO" used by SpaceX on many occasions specifically those related to payload capability. ...
8
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3answers
738 views

What difficulties will be faced modifying the Falcon 9 FT, so to have better and easier landings of the 1st stage from a GTO mission?

What difficulties will be faced making modifications for the Falcon 9 FT rocket, so in this way to make smoother, better and easier landings of the first stage from a GTO mission? For example ...
10
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1answer
441 views

How does a Falcon 9 booster know how far away the ground is?

In the latest landing video, it seems the Falcon 9 just hovered for a moment above the ship. That being said, it begs the question, how does the booster know where the ground is? Does it purely work ...
3
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2answers
209 views

How is engine thrust monitored during flight?

The failure of the Falcon 9 first stage landing during the Eutelsat/ABS mission was attributed to: thrust was low on 1 of 3 landing engines which indicate that engine thrusts are part of the ...
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4answers
2k views

Falcon 9 landing on drone ship 15/06/2016

I have watched last Falcon 9 landing and launch, but during landing screen froze. I have heard that it didn't landed successfully, so what happened with it, does anyone know?
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3answers
223 views

How variable is the landing spot of a reusable Falcon 9 with a GTO payload

It is common knowledge know that SpaceX uses the landing barges when the requirements for the first stages are so high that a return-to-base is not achievable. This seems to occur both in case of GTO ...
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0answers
64 views

What is the icy formation on these rockets? [duplicate]

I've sometimes seen icy formations form and break off of spacecraft. In today's SpaceX launch, there are a couple examples (times based on video) at 51:55 where you can see it growing: Two similar ...
3
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1answer
864 views

How will Sherpa and Formosat-5 be configured as payload and launched?

I was reading the comments in this Reddit and I'm confused. How will Sherpa and Formosat-5 be configured inside the Fairing, and then deployed. One comment seems to suggest that Formosat-5 is one of ...
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1answer
2k views

What work needs to be done before reusing Falcon 9?

In this article Elon Musk said that first stage of Falcon 9 which landed on the barge in April will be reused in June. Launching and landing wears material down, what parts need to be replaced and ...
5
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1answer
517 views

How much time does it take to circularize a GTO orbit using ion propulsion?

SpaceX launched two GEO comsats, and is about to launch two more, that use all-electric ion propulsion. Now, I'm wondering, how much time would it take to actually make a satellite like that ...
5
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1answer
526 views

Did the Thaicomm-8 SpaceX landed first stage move after landing?

The SpaceX Falcon 9 mission that launched the Thaicomm-8 satellite to GTO orbit, landed hard on the OCISLY ASDS barge. One of the legs over extended into the aluminum crush core and did not retract. ...
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1answer
2k views

Why did the Thaicomm-8 SpaceX First stage come into port leaning to the side?

The SpaceX Falcon 9 (F9-0025) mission that launched the Thaicomm-8 satellite to GTO orbit recovered its first stage. Looking at pictures of it coming into Port Canaveral we see it listing to the ...
3
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1answer
1k views

What is the structure of Falcon 9 and Dragon?

I mean detailed pics like this: If it's impossible to get this information please try to describe an approximate structure. Also provide additional info if you can. Which metal are used? What extra ...
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1answer
4k views

How effective are Falcon 9 1st stage grid fins in the last few seconds before landing?

This answer discusses the three methods that the Falcon 9 1st stage uses for attitude control during re-entry and landing. They are: cold nitrogen jets, "hypersonic" grid fins, and thrust vectoring of ...
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2answers
10k views

How does the SpaceX Falcon 9 first-stage straighten for landing?

I just saw this video of supposed "SpaceX Rocket Camera Landing Footage Fakery" with over a million views. The narrator repeatedly says it's complete garbage because he doesn't understand and would ...
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2answers
545 views

Will F9H's middle core receive more than max damage?

After partaking in a GTO delivery, the successful re-entry and landing of a Falcon 9 booster was described by Elon Musk as follows: Most recent rocket took max damage, due to v high entry velocity. ...
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2answers
750 views

How does Rocket performance compare to other things?

Typically cars are rated on their 0-60 mph times. (Tesla's currently kicking some serious gas car butt, where the P90D with Ludicrous mode hitting 2.8s which is literally ludicrous. As in you can hurt ...
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1answer
1k views

What causes the green flash during Falcon 9's ignition?

Right before Falcon 9's engines start, there's a green flash. I assume it's some kind of chemical ignition. What makes the flash the color green?
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1answer
829 views

Why were there green ignition flashes after Falcon 9's landing?

Whenever Falcon 9's engines start, there's a green ignition flash. During the latest landing there were similar green flashes right after touchdown: 1st stage landing (3 camera angles): ...
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1answer
506 views

How does the Falcon 9 first stage land on the moving surface of the barge?

From this question we know the barge can be held at a set position with an accuracy of one meter or so. So the barge doesn't really move in the X and Y direction. This takes care of yaw as well. But ...
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2answers
2k views

Is the Falcon Heavy booster much simpler to land than the Falcon 9 first stage?

Given the fact that the Boosters of the Falcon Heavy will separate much earlier during ascent (and hence at much lower speeds), there should be a notable difference in the complexity (and thus chance ...
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4answers
2k views

Would Falcon 9 sink on gentle splashdown?

Let's say the guidance system fails, and Falcon 9 first stage gently touches down on surface of water before switching the engine off (and plummeting into the water). Will it sink or will it float? ...
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2answers
330 views

What's the purpose of the white flashing lights on the Falcon 9 legs?

This is a questions which has been asked on Reddit after the landing at night of the booster used in JCSAT-14 mission, however no one has been able to provide a valid reason. The lights in question ...
3
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1answer
557 views

Technologies use by SpaceX to enable landing on a drone ship [duplicate]

Even when the Falcon 9 "punched the barge", it did so with extreme precision. SpaceX has now had several successful landings, many of them extremely spot-on. Two questions: There are obvious visual ...
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2answers
449 views

What are the version number and identification names for each Falcon 9-r boosters?

I would like to track the all the Falcon 9-r boosters that are landing or are attempting to land. I know that the third booster which landed successfully is the F9-0024-S1 but I don't know the ...
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2answers
1k views

Which has greater accuracy? Minuteman ICBM or Falcon 9 first stage?

The really fun part about watching SpaceX land their first stage on either their ASDS Barge (JRTI or OCISLY) or Landing Zone 1 on land, is they drew a nice target on the surface. There is a literal ...
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3answers
1k views

Is it normal for thrusters to “ice up”?

Towards the end of the JSSAT-14 webcast (around T+32:58), we see a thruster firing. Over the space of around 20 seconds, you can see it "icing up": What is this that's forming? Is this a normal ...
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1answer
581 views

How many booster stages can SpaceX store at Cape Canaveral?

Elon Musk tweeted this after the early morning successful landing of another booster on a barge: May need to increase size of rocket storage hangar How big is their rocket storage hanger at the ...
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3answers
487 views

Why rotate the Falcon 9 2nd stage after deployment?

Towards the end of the JCSAT-14 live webcast, after the satellite was deployed, we could see small thrusters firing on the second stage, starting to rotate it: The webcast ended shortly afterwards, ...
10
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1answer
946 views

If it is difficult for Merlin engine to have deeper throttling, could it be as an option a different engine at the center of the rocket?

In the landing procedure for the first stage of the Falcon 9 one concern is that : Merlin 1D throttling at its lowest level still generates more thrust than the empty mass of the first stage. So ...
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0answers
417 views

How long does it take to chill the LOX and RP1 for Falcon 9 V1.1 Full Thrust?

The new version of the Falcon 9 v1.1 Full Thrust, or as SpaceX would like everyone to start calling it "Falcon 9", uses super cooled LOX and RP1 to improve the density of the fuel for better ...
5
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1answer
559 views

Why is the Falcon 9 charred like this? [duplicate]

Every time we've seen a falcon 9 land or attempt to land, it's had a start change in coloration on the outside, just above the spaceX logo. It seems that the charring/exhaust smoke/residue suddenly ...
7
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1answer
713 views

How many engine firings can a SpaceX Falcon handle?

For every Falcon 9 launch to date, the process has been: Each Merlin is test fired/acceptance fired at McGregor by themselves. The entire stage is test fired at McGregor. The entire stage is hot ...