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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
144 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
18 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 ...
4
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2answers
68 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 ...
12
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0answers
217 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
174 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
576 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 ...
2
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2answers
187 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 ...
1
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1answer
178 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
115 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 ...
1
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1answer
85 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
533 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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82 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
62 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
105 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
263 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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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 ...
8
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1answer
286 views

What makes it so hard to precisely land a fairing?

SpaceX currently tries to land their fairing halves on a boat with a net attached to it. So far they had no success but landed nearby, although quadrupling the net area. They first tried with this ...
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0answers
107 views

Nature of “the silky black 'highly flame-resistant felt'” on Block 5 Falcon 9's, and its intended functions?

The Teslarati article SpaceX Falcon 9 Block 5 rocket’s drone ship return captured in stunning detail [gallery] and accompanying photo spread shows many interesting details of "SpaceX’s first West ...
6
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1answer
499 views

What is the minimal TWR of Falcon 9 booster right before touchdown?

A big point about Falcon 9 booster landing is that they need to stick the landing on the first try; they can't just hover and adjust position because even fully throttled single Merlin engine provides ...
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2answers
3k views

Will SpaceX delay launches, if the landing site weather is unacceptable?

With the initial landing attempts, it was not a big deal, twas all an experiment and they only reused Block 1-4 boosters once at best. So holding a launch because of weather at the landing site ...
4
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1answer
242 views

How do rockets “blow” smoke rings? Did “smashing through Max-Q” really do this?

The Teslarati article SpaceX delivers largest commercial satellite in kick off of Falcon 9 marathon includes several beautiful photos, of the Telstar 19V launch, including the one below. It shows ...
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0answers
315 views

Dragon 2 in-flight abort test - what will happen to the booster?

SpaceX is planning to do an in-flight abort test of the Dragon 2. I imagine that at max-Q the Dragon will start its own motors to fly slightly faster than the booster (and move sideways). Suddenly ...
31
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2answers
4k views

What holds SpaceX’s rocket in place in this launch?

On a recent launch video, the gantry is at an angle and only loose tethers are attached as the rocket is prepared for launch. What is keeping it upright and in place at this point? The engines haven'...
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3answers
334 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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4answers
4k views

Why does the Falcon 9 use RP-1/LOx and not LH2/LOx?

Why does SpaceX use RP-1 in the first and second stages of their rockets? In my view at least the second stage could use hydrogen as it currently is not being reused. I am aware that you have higher ...
12
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1answer
1k views

Why does the 2nd stage of Falcon 9 need compressed He tanks?

It is well known that the rapid disassembly of Falcon 9 static testing started with the rupture of the composite fibres of the copv He tanks. But what is the need to have the composite tanks ...
6
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3answers
501 views

Will reusable rockets be financially viable?

While the vertical landing of rockets by SpaceX is certainly a significant achievement, there seem to be many who say that reusability is not actually financially viable. Apparently, it is far too ...
4
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1answer
94 views

How far apart do both SpaceX half fairings splash down?

Inspired by this question: How far apart from each other (both in space and time) do the two halves of a Falcon fairing land? I'd also be curious to know what's the error margin they have on this. ...
7
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1answer
165 views

What are these tiles inside the Falcon 9 fairing?

The three photos in SpaceX's recent tweet about attempting to recover the GRACE-FO/Iridium-6 fairing halves included a close-up of the inside of the fairing: [] What do those black tiles with the ...
3
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1answer
262 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 ...
4
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1answer
624 views

How much does a current F9 fairing-half weigh?

Question: How much does a current F9 fairing-half weigh? Is this resting on something, or is it really floating this high in the water? Images from this SpaceX tweet: Falcon 9 fairing halves ...
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2answers
2k views

Why is the first stage from the Falcon 9 SES-12 mission not recovered?

Youtube video here At 4:13 minutes into the Iridium-6/GRACE-FO NASA Launch, the commentator mentions: The first stage is not going to be recovered, so there won't be any views from the drone ship ...
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3answers
362 views

What are these circular structures around the rocket?

Youtube video of the Iridium-6/GRACE-FO NASA Launch (Falcon 9 SES-12). Edit 31 May: Too bad they have changed the content of the video (and still call it 'live'), so that you can no longer see the ...
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1answer
170 views

Should SpaceX have 2 versions of the Falcon 9 rocket (cargo-only and human-only)?

I am learning that having a human rated Falcon 9 rocket is very difficult. Would it be better to have 2 versions of the Falcon 9 rocket? I figure a human-only version would be easier to design with ...
6
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1answer
255 views

Do Falcon 9/Heavy Block 5 boosters need landing legs? Or can they land back on their launch mounts?

At 2017's International Astronautical Congress, Elon Musk claimed that SpaceX could master propulsive landing without landing legs. The assertion was that Falcon 9's ...
3
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1answer
112 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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Non-axial thrust during Falcon 9 Block 5 launch? [duplicate]

Looking at video of the Block 5 launch today (2018 May 11) I noticed that from the ground tracking views, the vehicle roll axis and the exhaust plume appeared not to be collinear. When they cut to the ...
5
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1answer
313 views

What caused launch abort on SpaceX's Bangabandhu-1 launch

On Thursday, May 10th, 2018, SpaceX attempted a launch of the first Falcon 9 block V rocket carrying Bangabandhu-1 however the countdown was stopped at t-58 seconds and the launch was scrubbed for 24 ...
10
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1answer
457 views

What improvements does SpaceX Falcon 9 Block 5 have over prior version?

Does SpaceX disclose what improvements their Falcon 9 Block 5 will have over the Block 4 model? If so, what improved features will it have? I have heard general comments about it in the news, but I ...
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2answers
2k views

Can SpaceX Falcon 1st stage hover during landing?

I came across with this video in which the Falcon Heavy boosters' landing burn seems to deaccelerate the 1st stage until a point their speed is constant right before touchdown. ...
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1answer
5k views

Why is Falcon 9's fairing so big?

The Falcon 9 fairing costs millions of dollars. It is 5.2 meters wide while the rocket itself is only 3.7 meters wide. There is no aerodynamic reason that the fairing has to be so big, since Dragon ...
3
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1answer
462 views

Is it feasible to launch NASA's InSight mission Mars using a Falcon 9, instead of an Atlas V rocket?

The Insight mission is launching the spacecraft to Mars on May 5th aboard the Atlas V rocket by ULA. Would it have been possible to launch this mission using a SpaceX Falcon 9 Block 3/4/5 (expendable ...
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3answers
7k views

Why won't they recover the Falcon 9 from CRS-14?

According to the upcoming livestream of SpaceX CRS-14 (resupply of ISS): SpaceX will not attempt to recover Falcon 9’s first stage after launch. Why not? Wasn't that the whole point of (among ...
3
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1answer
123 views

Is a soot covered flight proven Falcon 9 lighter or heavier than a new falcon 9?

Since SpaceX now does not repaint or clean off the sides of the first stage booster prior to reuse, does this make the soot covered stage heavier or lighter? And is this difference in weight ...
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3answers
16k views

Why would NOAA restrict the ability of SpaceX to live stream the second stage?

I was watching the live stream of the Iridium-5 launch and they mentioned that NOAA had restricted their ability to live stream the second stage and that SpaceX was working to remove this restriction. ...
15
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1answer
3k views

Was SpaceX's launch of Formosat-5 more vertical than normal for any particular reason?

Reading both the abstract and the plain language summary of the recent paper published in the journal Space Weather Gigantic Circular Shock Acoustic Waves in the Ionosphere Triggered by the Launch of ...
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1answer
295 views

What's happening in this photo?

This is a 30 second exposure of the Falcon 9 launch on March 6th. The trail is from right to left; the photo was taken north of the launch site, about 3 or 4 minutes into the flight. I think I ...
6
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1answer
606 views

How did SpaceX achieve such a high Thrust to Weight ratio with the Merlin engine?

Were there specific breakthroughs which allowed SpaceX to get such an incredible thrust to weight ratio? The next closest American engine was almost twice as heavy (199 vs 82), and the next closest ...