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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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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 ...
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401 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. ...
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721 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 ...
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1answer
432 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 ...
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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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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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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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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 ...
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1answer
855 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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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 ...
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1answer
491 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 ...
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516 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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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 ...
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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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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
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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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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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672 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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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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771 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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497 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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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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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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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 ...
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1answer
540 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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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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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
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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
560 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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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, ...
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907 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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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 ...
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556 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 ...
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698 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 ...
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1answer
229 views

What is the launch profile for interplanetary missions typically like? [duplicate]

Elon Musk discussed in a question/answer session after the recent Falcon 9 launch that interplanetary missions are likely to use a landing barge, due to high horizontal launch speeds required for such ...
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Falcon 9 g-level/acceleration profile

I want to get an idea of how long the falcon 9 rocket accelerates and at what g level. Ideally a plot of gs vs time. I see various statistics like specific impulse and thrust and weight, is there a ...
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Falcon 9 fairings cost and reusability

I read that SpaceX is starting to work on fairings reusability. I couldn't find any information, so I would like to know more about them. In particular, I remember a quote from Musk saying that ...
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471 views

Does SpaceX have a disposable variant of Falcon?

If I understand correctly, Falcon 9 may be launched with no intent to land the first stage, when carrying exceptionally heavy payloads - in this scenario the fuel meant for landing is then used during ...
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1answer
783 views

How was SpaceX able to keep the rocket from tipping over on the barge? [duplicate]

How was SpaceX able able to keep the rocket from tipping over on the barge once it landed? The barge looked like it was rocking quite a bit.
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What is the maximum error to land on the barge?

In SpaceX's successful landing on the barge today, April 8th, we see there is almost no room for error, at least from the video: Note that it appears that the width of the drone ship is only about ...
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1answer
370 views

Why is the Dragon small compared with the Falcon 9 LEO payload

According to wikipedia, the Falcon 9 1.0 had ca. 10t payload capacity to LEO. The Dragon has a 3.3t payload capacity to the ISS with a dry mass of 4.2t that leaves 2.5t unused lift capacity. Is this ...
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NASA cost estimating and Falcon 9

I have found this interesting report Commercial Market Assessment for Crew and Cargo Systems Pursuant to Section 403 of the NASA Authorization Act of 2010 (P.L. 111-267), published in April 2011. In ...
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1answer
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SpaceX Webcast - What is visible in this clip? [duplicate]

I've just watched the SES-9 Launch Webcast and was wondering what is visible at about 37:15? Does the Falcon 9 have cameras in the kerosene (or LOX) tank?
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SpaceX first stage landing: Why not use an elevated net above the landing platform to catch the rocket?

The rocket would keep same descent system as now (no parachute). But instead of landing on feet, it would have long grid fins on its top that would be catched by an elevated cable net. The previous ...
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1answer
402 views

What was all of the junk in the SES satellite deployment?

In the SES launch on March 4, 2016, when the satellite deployed, there was quite a bit of junk that was released when the satellite was released. What was that?
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Is SpaceX the only launch service provider who can attempt another launch the next day after a scrub?

Is SpaceX really the only launch service provider, who can attempt another launch the very next day after a scrub? While other providers may need weeks of preparations before another try. If that is ...
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How long can a vehicle stay fueled before the liquid oxygen gets too warm?

On February 28 2016, Falcon 9 attempted a second launch for its 22nd flight. However, it was put on hold for about 20 minutes at T-01:33 and had its countdown reset to T-11:44, giving a total of about ...
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727 views

Why does SpaceX's Launch Complex 1 have four contingency landing pads?

An additional four 150 feet (46 m) diameter pads are planned to support the simultaneous recovery of additional boosters of the Falcon Heavy. on Cape Canaveral SpaceX landing Complex/Zone 1 wiki....
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752 views

How will SES-9 reach geostationary orbit from inclined transfer orbit (from F9 2nd stage)

This spaceflightnow article says near the end that the Falcon 9 2nd stage will leave SES-9 in an elliptical, inclined transfer orbit. This article says that this is a super-synchronous orbit, and that ...
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What will be “unique” about upcoming SES-9 GTO transfer profile by SpaceX?

In the SES-9 mission press kit, SpaceX mentions: "Given this mission’s unique GTO profile, a successful landing is not expected." What is considered "unique" about this transfer orbit's profile? ...