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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Is this soot building up on the Falcon 9 interstage?

In the below video of stage separation during Falcon 9's CRS-19 mission, the exhaust of Stage 2's Merlin 1D-Vac impinges on the interstage. It also deposits a black substance on the white paint: ...
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What happens to payload fairings of GEO launches?

Say you launch a satellite into GEO using Falcon9 The 1st stage returns The 2nd stage is moved into graveyard orbit. But what happens to the payload fairings?
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What prevents SpaceX from increasing the cadence of launches?

Many companies can afford and buy expensive launches (Ariane etc) so they prefer SpaceX to save money. Many other companies can't afford Ariane launches but they would afford Falcon 9 launches. Lower ...
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1answer
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How many times can Falcon 9's payload fairings be reused?

Falcon 9's first stage can be reused 10 times or even 100 times. But how about its payload fairings?
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When does Falcon 9 second stage separate?

For a regular LEO payload, when does the second stage separate? Usually the first stage separate 2:30 min after launch (and it takes 6 minutes to come back to Earth) so how about the second one? ...
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2answers
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Did SpaceX ever reuse payload fairings?

Did they ever reuse the payload fairings of the Falcon 9? There are a few related questions about maximum reuses and fastest refurbishment that might be asked later I guess
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Are Falcon 9 1st stages now always landed at sea?

Does the first stage of Falcon 9 now always land on a drone ships at sea? Say since 2016 or so.
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Electrical power requirements for Starship or Falcon 9

Anybody know where one could dig up electrical requirements for Starship? In other words, if Starship were sitting on the launch pad drawing power prior to launch, what would the load be? I imagine ...
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1answer
159 views

How long does the descent of the Falcon 9 first stage take?

After separating from the second stage, how long does it take for the Falcon 9 to come back to Earth? From LEO and from GEO. Note: this question is similar: How long does it take to recover the first ...
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Altitude at which Falcon boosters go subsonic during reentry

Is there a distinct altitude at which Falcon boosters goes subsonic during reentry? If so, which is it? Is it +/- the same altitude for every flight?
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1answer
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Falcon 9 second stage roll control: fins or dracos?

Unlike the first stage, the second stage has just one gimballed engine, meaning it can counter pitch and yaw perturbations, but not roll perturbations. Fins are effective for roll control, but at 50 ...
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Why would the Falcon 9 Block 5 carbon fiber thermal protection material need to be hydrophobic?

This answer to Nature of “the silky black 'highly flame-resistant felt'” on Block 5 Falcon 9's, and its intended functions? contains the following: This came into Falcon 9 design with Block 5 ...
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how much force can a falcon 9 landing leg handle

According to spacex, the falcon 9 landing legs are made of carbon fiber with aluminum in a honeycomb shape. How much force would be needed to break that?
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Do the ASDS barges have mission specific equipment?

End of June 2020, there was a planned Starlink (L9) mission on Jun 26, and OCISLY (Of Course I Still Love You, name of the vessel, really! Not making that up!) went out catch the stage. Then a few ...
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1answer
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What is the maximum apogee a Dragon spacecraft can reach?

What is the maximum apogee a Crew Dragon can reach in a highly elliptical orbit (by both the Falcon 9 and the Falcon Heavy)? There is a planned touristic mission in which the current apogee record of ...
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Were/Are the Space Shuttle or the Falcon 9 Dragon capable of achieving an elliptical orbit on whose apogee you'd see the entire Earth?

Was the Space Shuttle and is the Crew Dragon capable of achieving a highly elliptical orbit on whose apogee you could see the entire planet Earth? There will be a touristic flight soon in which an ...
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What is a “flight string”?

This answer explains what software powers the Falcon 9 launch vehicle. The flight software is written in C/C++ and runs in the x86 environment. For each calculation/decision, the "flight string&...
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Where will the DSCOVR mission Falcon 9 2nd stage rocket body end up?

This answer to Why would a mission to Sun-Earth L1 have an instantaneous launch window? suggests that this was quite a delta-v-intensive launch. It left the F9 2nd stage in a very high 17 day orbit ...
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Space-X Falcon-9 and Falcon Heavy fuel consumed for landing

The question is, how much fuel is used by each of above rockets for landing (in % of whole fuel of the rocket) as a function of three following components - payload, orbit and descend trajectory (land/...
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Where are Falcon 9 1st stage GN2 tanks located?

Is nitrogen propellant for the two cold gas thrusters pods contained in the interstage? The view we have from the B5-B1050 recovery shows several small COPV(s) pic1 Here you can see where the cold gas ...
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Why does the Falcon 9 launch 60 instead of 100 Starlink satellites at a time?

The Falcon 9 has a capacity of 22,800 kg to LEO. A Starlink satellite has a mass of 227 kg. That means that one Falcon 9 can launch 100 satellites. So why does SpaceX launch 60 instead of 100 ...
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1answer
123 views

How do Falcon 9 grid fins deploy?

Is it aerodynamic drag that flaps the grid fins open? Or is there a controlled mechanism for it? Pictures show the grid fins connect through a small link to something inside the rotating trunnion arm--...
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1answer
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Falcon 9: Why does F9 first stage always lose Video Link during Entry Burn?

Typically the F9 first stage and the drone ship each lose the video connection once during landing: F9 first stage during entry burn Drone ship during F9 first stage touch down (see here and here) ...
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1answer
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What factors do (or are expected to) limit reuse of a Falcon 9 block 5 first stage?

SpaceX have claimed (reported here) that the Falcon 9 Block 5 first stage should be reusable up to 10 times without significant refurbishment, and up to 100 times in total. What factors are expected ...
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1answer
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What are the needle pins that go through the pneumatic pushers of the Falcon 9 fairing?

The Falcon 9 fairing uses four pneumatic pushers to impart a positive separation force between the fairing halves. The pushers all mount on half of the fairing and push against the other half. But ...
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What are these cartridges with holes on the Dragon trunk?

You can see them on the rim in a hexagonal pattern in the picture below. Also present in the latest version of the Dragon trunk, but less clearly than here. They alternate in color from nickel to ...
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How does SpaceX Falcon 9 keep balance while it is near to the landing site?

As we know, flight vehicles can't keep balance easily if they cannot propel enough air through their blades or wings. We can also see the Falcon 9 at a steeper angle a while before touching down on ...
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1answer
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From what material and how are the Merlin engines and nozzles of it (sea level) manufactured?

I am specifically interested in the alloy used to build the engine, also about the nozzle: Is it just in one piece or welded using different sections. If they are welded then which welding techniques ...
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1answer
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Crew dragon falcon 9 first stage shut down

Crew dragon falcon 9 first stage shut down around 6700 km/hr and starlink shut down around 7900 km/hr, but around the same time. Is this because the crew dragon weighs more?
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1answer
110 views

Is the Falcon 9 second stage engine throttled down to limit maximum acceleration

Is the Falcon 9 second stage Merlin vacuum engine throttled down during its burn to limit the maximum acceleration experienced by the Dragon or Crew Dragon capsule? As the second stage consumes ...
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What became of slowing down and recovering the falcon 9 upper stage using large balloons

On 16 April 2018, Elon Musk posted on twitter This is gonna sound crazy, but … SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon And then land on a ...
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2answers
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What are the challenges in recovering Falcon 9's second stage this way?

The Falcon 9's second stage is currently disposed of each flight. I know there have been some concepts by SpaceX on making it reusable, but evidently they have not yet done so. From my understanding, ...
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Why are the Falcon 9 Stage-1 engines placed with offsets in the octaweb compartments?

Pictures of the octaweb show that the engines are not placed at the center of each octaweb compartment---they are closer to one side than to the other. See the picture below for an example. Focus on ...
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Is the outside surface temperature of a Falcon 9 below freezing? How is the LOX insulated?

This answer explains how the liquid oxygen in a Falcon 9 is evaporation cooled to maintain a temperature well below boiling, by bubbling helium through it. The temperature difference to the ...
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Will SpaceX paint over the NASA Worm on booster 1058 for its next flight?

For the Dragon Crew mission SpaceX flew a brand new booster (how declasse) B1058 and painted it with the old style NASA Worm logo. SpaceX owns the booster and is most likely to fly it many more times ...
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Falcon-9's subcooled LOX is continuously refrigerated in-situ, what about its subcooled RP-1?

@Uwe's answer to Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so? explains how subcooled LOX is kept cold and dense by "in situ refrigeration"; helium is bubbled ...
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Falcon 9 launch process - perception of launch speed

One of the things that drew attention from my local group of rocket-watchers with the Falcon 9/Crew Dragon launch is the perceived speed of the actual launch process. We have been conditioned for ...
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Can Falcon 9 be fueled slowed to delay the instantaneous launch window?

DM-2's first launch attempt was scrubbed at about T−17 minutes due to bad weather at the instantaneous launch window, even though the weather was predicted to clear up as early as T+10. It was ...
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1answer
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How does re-usable boosters by SpaceX return back and land on the deck 'Of Course I still Love You'? [duplicate]

The idea was to bring back the rockets/boosters safely and re-use them for next time. How SpaceX was able to achieve this? Intuitively there have to be multiple sensors recording and computer ...
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Why is the flame of the Falcon 9's 2nd stage (nearly) invisible?

During the first crewed flight of a Falcon 9 today, I watched the nozzle go from dark grey to glowing red hot, confirming that it was burning. Yet there were no visible flames. I understand this stage ...
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How was Demo-2's Falcon 9 booster different from any other F9?

According to The Sum Of All Knowledge, the Falcon 9 has only twice (including the 2016 ground fire destroying the payload) failed to put the primary payload in orbit. Thus, the May 30 2020 Demo-2 ...
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How does Falcon 9 differ from Shuttle or Apollo inertial guidance?

I read a very detailed analysis of the Saturn V. From it I learned there is a computer and guidance "room" which is an extra slice of rocket stacked between the 2nd or 3rd launch stages and the the ...
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2answers
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What specific threshold requirements or conditions is satisfied by the SpaceX Demo-2 Crew Dragon to warrant a manned flight? [closed]

I am wondering if there has been enough tests before the maiden manned flight of Demo-2 Crew Dragon. There were an autonomous flight test a year ago and a flight abort test late last year. There seem ...
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1answer
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What are the safety differences in launch conditions with Crew Dragon vs a normal launch?

During the scrubbed launch yesterday, one of the commentators mentioned there were more restrictions on crewed launches vs a launch of a satellite or Cargo Dragon. Is there a list of differences?
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Why isn't the Falcon 9 first stage severely damaged by the blast of the second stage following separation?

When the Falcon 9 experiences stage separation, why isn't the first stage severely damaged by the blast of the second stage? When separation occurs, there seems to be some mechanical force to push ...
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3answers
483 views

Why did SpaceX choose vertical integration for Starship?

Rockets are basically horizontally or vertically assembled and integrated. SpaceX selected horizontal integration for its current Falcon rockets, essentially for reasons of lower cost. This ...
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1answer
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How is fuel distributed in multi engine rocket stages?

How is fuel distributed evenly to multi-engine rockets like the Falcon 9, Electron, or multi-engined Centaurs? I would presume that there is only one main propellant line that goes down the raceway ...
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1answer
82 views

How is Cryogenic fuel kept… Cryogenic in rockets [duplicate]

How is cryogenic fuel & oxidizer kept at cryogenic temperatures in rockets? I am mostly interested in the first stage of launch vehicles rather than something like a Centaur that keeps hydrolox ...
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1answer
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Are new Falcon cores still being built at Hawthorne?

Musk has been saying for a while that at some point, they they will devote all their energy to the Starship. Falcon development has stopped at block 5, with no major iterations. It was never clear to ...
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How long does it take to refuel a rocket?

I've been wondering how long the refueling of a rocket, say the falcon 9 takes. That's it.

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