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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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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 ...
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1answer
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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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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
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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 ...
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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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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 ...
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1answer
128 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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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. ...
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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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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 ...
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1answer
622 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 ...
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1answer
221 views

Can (or will) Block5 Falcon 9s be used on the Falcon Heavy?

With the Block5 version of Falcon 9 booster soon to be flying, will they be used for the Falcon Heavy, or will they remain a stand alone thing?
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328 views

Why is there a coasting phase between the second stage engine cutoff and payload deployment?

[basing this question on the Falcon 9, Paz satellite launch on 22 Feb] Hi, this is probably a silly question, but there is an approx 3 minute time difference between second stage engine cutoff and ...
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Pressure inside a launch fairing - falcon 9

This article indicates that a faclon 9 launch is being delayed due to an issue with the "payload fairing pressurization system". Are launch fairings pressurized to 1 atmosphere for the benefit of the ...
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1answer
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Falcon 9 fairings stability on reentry

On the descent of the fairings into the atmosphere how is stability provided? Why does it not start to rotate in a uncontrollable fall but reenter gently without apparently damage on the interior ...
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What is that thing spraying during a Falcon 9 launch? [duplicate]

What are those things spraying something at the pad during the beginning of a Falcon 9 launch?
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What is this jet of material spraying out from Stage 2 during the SPACE-X PAZ mission?

This spray seemed to be there throughout the entirety of the Stage 2 burn but was especially visible once Stage 2 cutoff had happened. As that nozzle uses radiant cooling, it can't be cooling fluid, ...
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How do Falcon 9 fairings survive the reentry?

SpaceX recently tried to recover fairings from falcon 9, which landed intact in the ocean. How come these do not burn up during reentry?
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1answer
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Which engine failed during CRS-1?

During SpaceX's CRS-1 mission, "engine 1" failed, but the booster still completed its primary mission due to a plentiful thrust and fuel margin. Clearly, an outboard engine failure is more critical ...
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244 views

Starman and Tesla temperatures [duplicate]

As The Tesla car and Starman continue to orbit the earth, How does the paint on the car survive the extremes of temperature? As I understand it, they are both exposed to temperatures between 120C and -...
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What is the cause of this Falcon 9 first stage “dance” after landing?

Recently I watched a video on YouTube by Scott Manley: How To Do A Hoverslam - Things Kerbal Space Program Doesn't Teach. It deals about landing burns of Falcon 9 first stages. It features short clips ...
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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 ...
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What is pictured in the back of Falcon 9's 2015 launch photo?

Wikipedia (actually Wikimedia) has an image of Falcon 9's 2015 launch during its night flight (16th flight in total) that took place on Sunday, March 1, 2015 at 10:50pm ET: I was wondering what is ...
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Is a SpaceX launch completely automated?

Once the engines are ignited and liftoff occurs, are any operators/controllers on the ground making any manual changes to the flight? Or are they simply monitoring the entire event until the boosters ...
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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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1answer
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Can Falcon Heavy side boosters/center core be reused as Falcon 9s?

Since the Falcon Heavy is just essentially 3 Falcon 9s strapped together, would it be possible to reuse them as Falcon 9s with some modification?
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If the SpaceX drone ship's camera feed gets disrupted every landing, why cant they throw the antennae off the ship on a buoy for better reception?

They mentioned on the live stream that this is because of the shaking antennae. It has also been discussed on here before why this happens: Why does the video feed always fail during Falcon 9 ...
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What is the velocity profile of a Falcon 9 first stage landing?

How fast is it travelling as it comes into landing, before and after the re-ignition of the engine, and how quickly does it decellerate?? I would expect that it would be falling at about terminal ...
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416 views

Would it be beneficial to land Falcon Heavy's side boosters on droneships too?

Although the synchronous landing of the Falcon Heavy side boosters looks impressive, they seem to have traveled a long way back to the landing zones. How does this ...
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3answers
624 views

Will SpaceX land the first stage for the TESS mission on land or a barge?

I may have the opportunity to watch the upcoming Falcon 9 launch of NASA's TESS mission in person. Because of this, I'm curious whether I'll be able to watch the first stage of the Falcon 9 land back ...
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1answer
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Could the SpaceX Falcon 9 Block 5 work without sub-cooling the propellants?

I've been reading about some concerns about the densified (sub-cooled) propellants for Falcon 9 crewed missions in Spaceflight Now's article Lawmakers question safety, schedule for Boeing/SpaceX ...
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What is the turnaround time for SpaceX's barges?

I believe that currently, SpaceX only has two landing barges - one in the Atlantic (Of Course I Still Love You (OCISLY)), and one barge in the Pacific (Just Read The Instructions (JRTI)). How long ...
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Why did the “Secretive SpaceX Zuma Launch” make a big “S” or yin-yang shape in the sky?

The Space.com article Strange Sky Spiral May Come from Secretive SpaceX Zuma Launch shows images from this Tweet and this tweet, the second of which was posted by Dr Marco Langbroek (@Marco_Langbroek):...
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What was the outcome of the launch of ZUMA by SpaceX, to the best of the public's knowledge?

Now, I realise this question is inherently unanswerable due to the classified nature of the mission, and speculation is also not desirable, but that's okay — because we can at least assemble official ...
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Why did SpaceX retire Falcon 1?

Why did SpaceX retire Falcon 1? Wouldn't it have been more cost effective then Falcon 9 for lighter missions?
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Is there any flutter analysis available regarding Falcon's grid fins?

I have never come across any papers which talks about flutter analysis of gridded fins in general, does it not under go flutter behavior or is it technically incorrect to talk about flutter for ...
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1answer
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Why are Falcon 9 main engines throttled down and up shortly after launch?

On the official webcast of SpaceX's Iridium-4 mission a "throttle down and throttle back up of the Falcon 9 first stage engines" is mentioned. Why would one throttle down at a crucial time during ...
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SpaceX's Iridium 4: Explanation of Trail Footage

There is a lot of footage of SpaceX's Iridium 4 mission of 22 Dec 2017. The rocket's vapor trails look very different from those of airplanes, since it gains a lot of height. Anyhow, the result looks ...
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Why are the new Titanium Grid fins not used on all Falcon 9 landings?

With the Block 4 version of the Falcon 9, one of the new features is the Titanium Grid fins, vs the previously used Aluminium fins. However, not all Block 4 flights have used the Ti vs Al fins. Is ...
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Why does one leg open slower than others on Falcon 9 landings?

I had noticed this before, but when landing, the legs do not open at exactly the same time or speed. For the CRS-13 mission, it was really obvious in this video around 50 seconds into the video. ...
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Why are CCD cameras still used, not CMOS for live view from the rocket?

I watched the start of the CRS-13 and the view of the engine and other elements of the rocket are shown from CCD cameras in sd. The resolution ok, does not have to be large but why is it still used ...
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What fuel is used in the second stage of orbital launch vehicles?

What types of propellant are used in the second stage of multi-stage rockets? For example, the Falcon 9. Is it the same combination as the first stage? I've found plenty of information about the first ...
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1answer
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Why is LC39A's TEL enclosed, but the newer SLC40 TEL is not?

After the AMOS-6 explosion on the pad at SLC-40 in September 2015, SpaceX spent a lot of time rebuilding SLC-40, including a very big update on the TEL (Transporter/Erector/Launcher). Whenever they ...
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Could a Falcon 9 booster return to Earth with its payload safely in an emergency? [duplicate]

Suppose that during the boost phase a Falcon 9 lost enough engines that it could not deploy its payload into a useful orbit or trajectory. Are there some scenarios where it could conceivably return ...
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1answer
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Falcon 9 Merlin engine thrust vectoring

One of the ways that the Falcon 9's attitude is controlled is through thrust vectoring of the main Merlin engine(s?). In images of older thrusters i've seen hydraulic or electric linear actuators to ...
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2answers
390 views

How does SpaceX phased array system work to keep track on the rocket

I have heard that SpaceX uses some kind of phased array system. I guess, this is reasonable because the speed of the rocket makes usage of any movable parts impossible. However, I am not an engineer ...
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How does the Falcon 9 achieves horizontal flight control [duplicate]

Landing of a rocket seems impossible with vertical flight control only. How the rocket achieves horizontal flight control with engines in line with the booster?
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1answer
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Falcon 9 design: Why is the cargo fairing so much wider than the lower parts?

Why does the cargo fairing have a much larger diameter than the lower part of the rocket? Of course a larger diameter lets thicker payloads fit. But then the first, inter, and second stage could have ...
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1answer
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?
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1answer
530 views

What's this chunk that fell off Falcon 9 second stage?

Just after T+3 minutes during today's SES-11 launch I noticed a small chunk fall off the end of a "boom" on the Falcon 9 second stage. What's the boom and what came ...