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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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How many SpaceX Starlink Internet-service satellites could be deployed in a single Falcon 9 launch? Falcon Heavy? BFR?

The mass of the two test satellites being launched this month is 400 kg, but I don't believe that includes the antennae and the structure to hold and release them. Is total mass the only constraint or ...
3
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1answer
134 views

Will Falcon 9 block 5 successful launch speed up production of BFR?

I was just wondering that as Spacex has just launched it's final variant of Falcon 9 block 5 successfully, so now will it speed up the process of building BFR rocket ?
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2answers
1k views

Why is BFR replacing the Falcon 9?

Not every payload (or even batch of payloads) needs super-heavy launch capacity, but that seems to be what SpaceX is doing. https://www.space.com/38323-spacex-phasing-out-rockets-for-mars-bfr-...
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2answers
3k views

How much fuel can SpaceX save by landing the Falcon 9 booster on a barge?

It sounds from the text of this tweet like Elon Musk plans to continue to do barge landings over the long term: "Base is 300 ft by 100 ft, with wings that extend width to 170 ft. Will allow refuel &...
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3answers
439 views

Why are these Falcon 9 1st stage bodies (apparently) wrapped in black plastic for transport?

The Teslarati article SpaceX’s third Block 5 rocket heads to Texas test site as launch marathon nears includes the image and caption below. Is this an unused rocket body being transported for launch, ...
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0answers
43 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 ...
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0answers
66 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 (...
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3answers
5k views

What are the consequences of Vertical vs Horizontal integration for SpaceX?

One of the issues the Air Force has with using SpaceX as a launch provider is that their payloads are designed for vertical integration. That is, the booster stands on the pad upright, and the ...
2
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1answer
356 views

DId the Falcon 2nd stage turn around [UPDATED] and point “backwards” before the Orbcomm-2 deployement started?

It looks to me like the camera used for the deployment part of the Webcast shown on YouTube is located near the "bottom" of the payload area (closer to the engine & tanks) - in which case, did ...
25
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1answer
17k views

What are the droplets/particles falling off rockets at launch?

In this picture from the AsiaSat 6 launch by Falcon 9 on 8th September 2014, the part of the rocket between the fairing and the engine appears to be surrounded by dust, water droplets or debris: And ...
14
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1answer
784 views

What is the value of the cross-track angle between the two designated CRS-4 first stage recovery zones?

For the SpaceX Falcon 9 launch on its Dragon/CRS-4 cargo delivery mission to the International Space Station, according to Spaceflight 101, two downrange safety zones have been identified: The SpX-...
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2answers
166 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
75 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-...
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2answers
1k views

Has SpaceX re-used a first stage twice yet?

SpaceX has re-used a first stage once, several times now. Has it re-used the same first stage twice yet? If not, has a particular mission been named that will be the first second re-use?
7
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2answers
811 views

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? ...
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0answers
63 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, ...
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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 ...
27
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5answers
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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 ...
3
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0answers
50 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 ...
1
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1answer
71 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
141 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 ...
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1answer
63 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?
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1answer
155 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 ...
5
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2answers
219 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
204 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
264 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, ...
10
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1answer
325 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
86 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
146 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
212 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 ...
7
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2answers
574 views

What is a “re-radiation system”?

In SpaceX's Echostar XXIII Hosted Webcast after T+ 00:03:50 they mentioned the "re-radiation system" as a part of the payload fairing that increased it's value and ...
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0answers
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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 ...
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0answers
281 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 ...
5
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2answers
79 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 ...
3
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1answer
271 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
642 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
248 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
298 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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3answers
220 views

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
185 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 ...
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2answers
586 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
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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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2answers
3k 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 ...
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2answers
4k views

Calculate Falcon 9 CO2 emissions

Falcon 9 uses Merlin 1 Kerosene based engines. Are there 4 Merlin 1 engines? This seems simple to calculate: Number of Merlin Engines x Merlin 1 fuel capacity(gallons) x Kerosene to CO2 Production. ...
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0answers
111 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
64 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 ...
2
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1answer
275 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 ...
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1answer
128 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 ...
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4answers
9k views

Why can't Falcon 9 fairings touch the water?

SpaceX is spending considerable effort to catch Falcon 9 fairings into a giant net on a ship. I am aware that salt water ruins almost everything in the long run, but the fairings are a composite ...