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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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1answer
148 views

What does this SpaceX tweeted photo show and what causes the pure red and blue color?

This May 4, 2019 SpaceX tweet says More photos from Falcon 9’s 40th successful launch from Pad 40 in Florida and 39th first stage rocket booster landing to date → http://flickr.com/spacex and ...
3
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1answer
167 views

Can we get to Mars today using current rockets/technology?

I was wondering if, using the rockets we have today (I'm guessing the most likely candidate is the Falcon Heavy), we could send at least 1 human to Mars. For arguments sake, let's ignore the fact it ...
3
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1answer
123 views

When Falcon 9's stage 2 engine fires up, does the flame of the engine affect stage 1 in any way?

Are there any specific design considerations that are made over nonreusable, traditional rockets to tolerate the blast from the stage 2 engine? As shown in this moment:
5
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2answers
241 views

Is this Falcon 9 on a drone ship in Port Canaveral on fire?

The Teslarati article SpaceX’s latest Falcon 9 booster returns to port as NASA hints at “vested interest” shows this tweet about booster number B1056 from Jennifer Krafft Photography: #SpaceX #...
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0answers
60 views

Books on Vertical-Landing Vertical-Takeoff (VTVL) of Rockets? or Rocket Design in General?

I am working on a rocket control system design and I am trying to understand the the fundamental principles and concepts to design an efficient controller for recovering and landing the rocket, ...
3
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1answer
176 views

Could Falcon 9 take off without launchpad

As far as I'm currently aware, the Falcon 9 block 5 does not have the capability to retract it's landing legs once they're deployed, however: If F9 landing legs had the ability to retract themselves (...
5
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1answer
390 views

What exactly happened to crew dragon on 4/20?

The crew dragon experienced an anomaly yesterday during testing. It seems that there was some sort of unexpected event that resulted in damage to the crew dragon test article. This unconfirmed video ...
1
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0answers
80 views

How many SpaceX 2nd stages are in heliocentric orbits?

I can think of one particularly famous SpaceX 2nd stage in heliocentric orbit that even has its own website: https://www.whereisroadster.com/ and I know one was used to send DSCOVR towards Sun-Earth ...
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0answers
85 views

What would be payload capacity of reusable Falcon 9 if there was no atmosphere on Earth?

Reading this question and answers, I wondered what would happen if there was no atmosphere, everything else being the same on Earth. What would be the payload capacity to LEO of Falcon 9 in reusable ...
3
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0answers
106 views

Are these two length scales in FH exhaust plumes real, understood, and distinct?

The Ars Technica article We can admit it—we’re dazzled by the controlled fury of the Falcon Heavy includes a beautiful photo of the exhaust plume produced by the 27 engines of a Falcon Heavy launch. ...
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0answers
50 views

SpaceX Avionics [closed]

Just wondering what are some avionics aboard the falcon 9 and heavy. also what are some avionics on the dragon? Just general avionics that play a pivotal role in space travel.
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5answers
3k views

Why does Arabsat 6A need a Falcon Heavy to launch

Is it just me or does a falcon heavy seem like a bit of an overkill to launch Arabsat 6A? Falcon Heavy - GEO payload: 26,700 kilograms Arabsat 6A - weight: ~6000 kilograms Wouldn't some other ...
9
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1answer
207 views

Why is the Falcon Heavy interstage not black?

Falcon Heavy has two side boosters that are essentially standard Falcon 9 lower stage with a nose cone, along with a black interstage, as seen below. But the renders that SpaceX shows of Falcon Heavy ...
3
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0answers
124 views

Falcon 9 Landing Speed

I wanted to know what the fastest speed is that a Falcon 9 can land at and thus the max force the landing legs can withstand. I assumed the mass when landed is 26,000 kg (I once heard that somewhere). ...
3
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1answer
129 views

What's the shortest time to reflight of a Falcon 9 booster?

What has been the shortest time in between the landing of a Falcon 9 booster, and SpaceX reusing them on a different mission?
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1answer
116 views

How are 9 Merlin 1D engines packed and able to fit in a Falcon 9 FT first stage?

It was proved by Pirl in 1969 the most optimal packing of 9 circles in a larger one https://en.wikipedia.org/wiki/Circle_packing_in_a_circle. The radius of the larger circle should be ≈ 3.613r (r is ...
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0answers
64 views

Calculating the height and width of a rocket for drag

While messing around with making a little rocket launch simulator, I seem to have hit a slight wall with finding the relevant information in order to calculate the width and height of the rocket for ...
4
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0answers
111 views

Falcon 9 2nd stage pusher; how far does it continue to extend as it accelerates separation?

I've just watched Scott Manley's video SpaceX's Water Landing Reveals Rocket "Secrets" (or, What We Learned from CRS-16) (again) and he mentions the second stage "pusher" in the center of the view (...
3
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2answers
200 views

Is helium used to power the Falcon 9 grid fins?

Is helium used as a hydraulic fluid to power the grid fins? Or for engine gimbaling? What are the pros and cons of using helium instead of hydraulic fluids?
3
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1answer
116 views

The changes of a throttled Merlin-1d engine

With Merlin-1d being able to throttle down from its full thrust potential, this post about its throttle capability does not mention much of its change in performance. On the Wikipedia page of Merlin-...
5
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0answers
76 views

In landing, how much of a Falcon 9 First stage's velocity is lost to air resistance and how much to retropropulsion?

Thinking about this question I was led to wonder to what extent retropropulsion is used to kill the F9 first stage's full velocity and to what extent it is used simply for course control and landing, ...
7
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2answers
1k views

How many engines are restarted for landing the falcon boosters

For landing the boosters, it is clear that SpaceX is using the center engine, but I suspect that igniting one engine will not be helpful. If they aren't igniting all the 9 engines, how are they ...
3
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0answers
70 views

Falcon 9: how much fuel is left on a booster after stage separation?

If the booster attempts either land or sea landing, how much fuel (RP-1 and LOX) is left in its tanks right after stage separation? Recently, I have heard numbers as high as 30% of its total tank ...
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1answer
95 views

Does the Falcon 9 charge its batteries during flight?

I'm wondering if the Falcon 9 booster or upper stage regenerates any electrical power from the Merlin engines or their subsystems, or if the battery systems are perpetually draining while in flight (...
4
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1answer
179 views

Why was the water-landed Falcon 9 B5-B1050 towed backwards for retrieval?

The rocket was apparently recovered by attaching a towing line to the heavy, lower end (with the engines) and pulling at backwards. This seems counterintuitive to me, as this pushes the water into ...
2
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1answer
95 views

What are the four vertical structures surrounding Falcon launch? [duplicate]

This image is on the first page of the Falcon 9 Launch Vehicle PAYLOAD USER’S GUIDE which features Falcon blasting off and four masts with cables attached to their tops. What are they?
4
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1answer
238 views

Why did they not use the Flight Termination system on CRS16 booster?

All US boosters (I assume other nations as well) have flight termination systems. The goal is to try and stop an out of control booster (Big vehicle, full of explosives/fuel/oxidizer) from causing ...
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5answers
5k views

Falcon 9: engines stabilize spin

On CRS-16, the landing Falcon 9 booster entered a spin rotation due to a stalling grid fin hydraulic pump. According to Musk, the engines stabilized the spin. How is this possible? The main engines ...
5
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2answers
243 views

If the CRS16 booster was out of control, how did it abort to water?

The CRS-16 missions first stage, seems to have had a stuck grid fin. Apparently a hydraulic pump failed. It was spinning fairly wildly and clearly did not try to land at the pad as it was scheduled. ...
7
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1answer
213 views

What is the circular item that fell off of the returning booster during the CRS-16 mission?

During reentry of the first stage booster on the Dragon Resupply Mission (CRS-16), there was a ring-looking item that floated away from the booster. I would imagine it is some sort of ice debris, but ...
5
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2answers
313 views

What are these flames on the Falcon 9 booster?

When Falcon 9 was on its way to ascend, flames appeared around the bottom of the booster. What are they? It seems to begin around about 20:36 in the video, ...
5
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1answer
99 views

Loading the LOX into Falcon 9 V1.1 and Falcon 9 Full Thrust

It is clear from the spaceflight101.com that there is difference in Launch sequences of Falcon 9 FT and Falcon 9 V1.1. Clearly, Spacex has found a way to load the tank in 30 minutes (falcon 9 FT) as ...
5
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1answer
211 views

How long does the refurbishment process of a Falcon 9 take?

When launching a reused Falcon 9, how much time would it take to refurbish a used first stage in order to get into working condition? NOTE: This question is different as it looks at the time between ...
9
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1answer
236 views

What is the mysterious cube shaped object observed in the Falcon 9 launch? [duplicate]

For today's(November 15 2018) Falcon 9 launch, at around T+ 06:04 into the mission, we can see a cube shaped object flying near to Falcon 9 first stage. This ...
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0answers
27 views

Gimballing angle consider for liquid rocket engines [duplicate]

I went through the documents for gimbaling of liquid rocket engines and saw that there is about 20 degrees per second of gimbaling rate (in comments). But I am not able to get, what is the maximum ...
5
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2answers
143 views

what's this fluffy object on the SAOCOM 1A mission's upper stage? [duplicate]

When watching the upper stage of the Falcon 9, I noticed this white or blue tuft: It changes shape a bit as time goes on. That makes me think it is something very light (cotton candy, fiberglass ...
16
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1answer
420 views

Why is the exhaust plume of Falcon 9 upper stage shaped the way it is?

The (single) Merlin 1D vacuum engine's exhaust plume has a symmetric shape, comprising of six distinct "inner" plumes. Why does it have this shape? Is it due to the shape/configuration of fuel ...
3
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1answer
339 views

How do you shut off a Merlin-like rocket engine quickly? How quickly can it be done?

After about 36:17 in part 1 of this recording of SpaceX's Hans Koenigsmann's talk at IAC 2018, he narrates the propulsive landing of a Falcon 9 first stage, and ...
2
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1answer
677 views

What flame is SpaceX's Hans Koenigsmann describing in his presentation?

At 35:46 in part 1 of this recording of SpaceX's Hans Koenigsmann's talk at IAC 2018, he says something like: The green stuff that you see is TEA-TEB, that’s the ...
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2answers
312 views

Does anyone know how the Flight Club website simulates Falcon 9 launches?

Does anyone know how the Flight Club website is able to provide falcon 9 launch simulations? Given the estimated weight, fuel mass, thrust, ect, how are they able to provide a graph of how it could ...
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1answer
571 views

Is it possible to calculate Max-Q without having to input an altitude

Is it possible to calculate max-q based on just upwards velocity instead of specially inputting a given altitude/air density? Based on this graph of Falcon 9 launches till MECO below "Air Pressure vs. ...
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1answer
184 views
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3* Tonnes Unaccounted for in Falcon 9 FT Weight Wikipedia Calculation?

On the Falcon 9 FT Wikipedia page, the fully fuelled weight of Falcon 9 is only 546 300kg instead of 549,054kg as stated on SpaceX website. 546,300 kg - Wikipedia ...
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1answer
391 views

What is the Kerosene/LOX mixture ratio of the Block 5 Falcon 9?

as the title would suggest, does anyone know a calculation or solution to finding the current mixture ratio used on the latest block 5 configuration? This would be easier if so many people did not ...
7
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2answers
797 views

Does anyone know how to calculate the KG per second of RP-1 and LOX from the 9 Merlin 1D engines?

as can be seen from the title, I have been through at least 1,000 chrome tabs in the last few hours trying to find some form of definitive answer, but I've found absolutely nothing. Could anyone help ...
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3answers
7k views

What is the primary reason for SpaceX motion to have astronauts board Dragon before fueling up the rocket?

News piece: NASA supports SpaceX plan to fuel rockets with astronauts on board. The move is criticized by many as unnecessarily dangerous. From what I understand though, it shouldn't be necessary - ...
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0answers
146 views

Does the downrange position of an ASDS vary, depending on payload mass?

SpaceX in its recovery attempts can either do a Return To Launch Site (RTLS) or land downrange on an ASDS landing barge. The Telesat 19V and 18V payloads were some of the heaviest payloads on the ...
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0answers
65 views

Falcon fairing half - between separation and parachutes deployment

How does Falcon fairing half behaves in atmosphere before parachutes deployment? What is its free fall attitude in atmosphere? Is the fairing's attitude stable (with some wobbling, but without ...
1
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1answer
160 views

Would having the Falcon fairing reconnect be possible/beneficial?

I understand that many of the problems with recovering the two pieces of the Falcon 9 fairing deal with the weird aerodynamic patterns of the descent. It is by no means an aerodynamically sound object ...
2
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1answer
313 views

Why doesn't SpaceX deploy some module to cover whole fairing like a rain coat just before sea landing? [duplicate]

In order to avoid fairing to get wet in water, why can't SpaceX just deploy something such that when fairings separate from the Falcon 9 then from inside some raincoat type waterproofing to just cover ...