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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)

8
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1answer
145 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 ...
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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 ...
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
122 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 #...
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. ...
14
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1answer
813 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-...
4
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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
389 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
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 ...
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 ...
2
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2answers
687 views

Why has no TLE been published for the DSCOVR satellite and the Falcon 9 R/B?

So, usually a few days after every launch, I go out and check out the published TLE data for each satellite, made public courtesy of CelesTrak. It generally includes all the orbital parameters for ...
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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 ...
14
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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 ...
4
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2answers
443 views

How does SpaceX decide which half of the Falcon 9 fairing to catch?

Question: How does SpaceX decide which half of the Falcon 9 fairing to catch if they are only going to catch one half? Is one half more expensive and/or well instrumented than the other? Images from ...
1
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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.
22
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4answers
3k views

How does the Falcon 9 know where the landing barge/pad is?

The descending Falcon 9 has got to hit (preferably gently) the tiny target of the Autonomous Spaceport Drone Ship (ASDS) in the middle of the ocean. How does the Falcon 9 know where the ASDS is? ...
18
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3answers
14k views

What are the differences between a standard Merlin engine and the Merlin Vacuum engine?

I know that there's a difference between SpaceX's Falcon 9 1st stage engines and the 2nd stage engine, since that stage is specifically tuned for vacuum. Wikipedia also says that the Merlin Vacuum ...
4
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1answer
269 views

What was the cause of the second explosion in SpaceX's pad “Fast Fire”?

This is well after the first and second stage were gone, so I suspect it was something about the pad itself that resulted in the second explosion event. Any ideas?
16
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1answer
419 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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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). ...
14
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3answers
4k views

Is the supercooled LOX used in Falcon 9 Full Thrust a first?

One of the changes made to the Falcon 9 v1.1 Full Thrust was using supercooled liquid oxygen at 66 K (-340 F) as well as chilled RP-1. I've seen various claims that this is a first in the industry. ...
9
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3answers
824 views

Final conclusion/description of the cause of the SpaceX Sept. 1, 2016 anomaly? What's a “buckle”?

I've just read the phys.org new item which summarizes the conclusions by SpaceX about the cause of the September 1st 2016 anomaly. I'm citing quotes in the news item which come from a SpaceX ...
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?
-1
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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 ...
20
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3answers
4k views

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
136 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 ?
7
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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-...
13
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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 &...
5
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3answers
532 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
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 (...
7
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3answers
6k 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
363 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
19k 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 ...
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-...
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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
852 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? ...
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 ...
27
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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 ...
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 ...
1
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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 ...
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. ...