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Questions tagged [spacex]

Space Exploration Technologies Corporation, or SpaceX, is a private space exploration company. It was the world's first privately held company to successfully launch a cargo mission into space.

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Starman/Roadster in a=1.795 AU orbit, now what's the method to this madness?

The question SpaceX's 4,425 satellite constellation - what's the method to the madness? received an excellent answer explaining the rationality behind the madness plan. Elon Musk's tweet (spotted ...
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SpaceX's 4,425 satellite constellation - what's the method to the madness?

The BBC article SpaceX aims to launch internet from space discusses the SpaceX proposal for a dense array of over 4,000 LEO satellites for global internet coverage, and links to SpaceX non-...
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Is it possible to track an object as small as the Tesla Roadster around the Solar System

I have heard that we will soon lose track of the Tesla Roadster launched with the Falcon Heavy test launch. Yet, we know where Voyager is out beyond the Solar System and we followed other satellites ...
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Why would SpaceX not use parachutes for the final descent of the first stage?

According to what I've read, SpaceX tried to use parachutes to recover the first stage of the Falcon 9, but it did not survive reentry. Now they plan to use 2 separate rocket burns to land: Reentry ...
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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 ...
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1answer
867 views

How strong and “hot” is the wind on the payload after the fairing is deployed at ~110km?

In the question What makes 21st century fairings so valuable that they'd potentially be recovered and re-used? I said: 21st century fairings are much more than passive rooftop boxes to "keep the ...
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6answers
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Can I drive Elon Musk's Tesla after it's been in space for 100 Years?

We know that the the payload of the maiden Falcon Heavy flight will be... Elon Musks's Tesla Which will be placed in "Mars Orbit" Assuming it is serviced and road ready when launched with the keys in ...
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What are the towers around the SpaceX launch pad used for?

I noticed four(?) towers around the SpaceX launch pad during yesterday's aborted launch Image credit NBC News What are the towers used for? Tracking? Radio communications?
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Current speed of Tesla Roadster which is moving toward the Asteroid Belt?

I am just wondering at what speed does Tesla Roadster is currently travelling toward the Asteroid Belt (Relative to Earth)?
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Is it normal for thrusters to “ice up”?

Towards the end of the JSSAT-14 webcast (around T+32:58), we see a thruster firing. Over the space of around 20 seconds, you can see it "icing up": What is this that's forming? Is this a normal ...
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Will the Tesla Roadster return any telemetry?

Is there any equipment fitted to the Tesla Roadster to send signals back to Earth, even for a short time after launch?
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754 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 ...
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Can five refillings of the BFR second stage be useful to get to the Moon? To Mars? All five in Earth orbit?

EDIT: Here are some BF numbers from the video: ...
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1answer
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Cause of apparent plume deflection on SES-10?

While watching the SES-10 flight, starting a little after T+1:30, I noticed that the direction of the first-stage exhaust plume started to diverge from the alignment of the rocket body. The ...
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2answers
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If not constrained by underpasses, etc., would Falcon 9 have been less of a flying noodle?

This excellent answer to the question Why is Falcon 9's shape so tall and skinny? mentions California, Florida, Texas and Alabama, within and between-which there must be at least a few limiting ...
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SpaceX CRS-5 Launch: What is the footage that appears to contain bubbles?

I'm currently watching the live stream of the CRS-5 launch. They've been cycling through several different camera angles including one which looks a lot like bubbles in water, or perhaps blobs of ...
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What makes 21st century fairings so valuable that they'd potentially be recovered and re-used?

I've read in @geoff's answer that SpaceX is doing some experimentation that may lead to fairing recovery capability. In fact I remember hearing Elon Musk mentioning a few years ago that it was being ...
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1answer
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Rocket Engine Plumbing: Still don't understand the Full Flow Staged Combustion Cycle

I just found this incredible video KSP Doesn't Teach: Rocket Engine Plumbing and ran through it a few times. It's very helpful in the way it outlines the various issues first, and then designs the ...
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1answer
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What is the cause of the blue light from LH2/LOX rocket engines?

Below are some screen shots from circa June 2016 launch (or re-launch) videos by Blue Origin (video link) and SpaceX (video link). The New Shepard burns $\text{H}_2$/$\text{O}_2$, while the Falcon 9 ...
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1answer
762 views

Merlin Engine Stoichiometry

As evidenced by the bright exhaust plume at launch, the billowing black smoke rolling out of the flame trench during static tests, the wispy grey effluent from the Merlin Vacuum engine, and the layer ...
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How stable would a Falcon 9 first stage be after it has landed on a drone ship?

Presumably, the booster would be a very light, very tall tube (Most of the fuel spent) standing on 4 fairly small legs on a ship in the middle of the ocean. It would also still contain some LOX and ...
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Why would a mission to Sun-Earth L1 have an instantaneous launch window?

I was watching the webcast for Falcon 9 Flight 15 (launching DSCOVR) when they scrubbed their first launch attempt due to some issues during the terminal countdown. Before the scrub, the narrator ...
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Can Falcon 9 first stage landing final burn using one, two, and three engines? Tradeoffs?

This question is about the final burn in the landing sequence of the Falcon 9 first stage return to Earth tests. If I understand correctly, there is usually far more thrust than there is weight at ...
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How are the SpaceX Falcon 9 Mod 3 and Mod 4 grid fins different?

Elon Musk tweeted "Flying with larger & significantly upgraded hypersonic grid fins. Single piece cast & cut titanium. Can take reentry heat with no shielding." These have been commonly known ...
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How is SpaceX going to land their Falcon first stage?

SpaceX's attempt at a reusable first stage rocket sounds amazing, but how they're going to get it to land back on the launchpad is beyond me. Assuming that the first stage will separate with a speed ...
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Why were three engines used for the F9 1st stage landing burn (BulgariaSat-1)?

As pointed out in the question What is the “emergency crush core”?, an Elon Musk tweet about the Falcon 9 1st stage landing following the BulgariaSat-1 launch says: Rocket is extra toasty and hit ...
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2answers
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On the Falcon Heavy, why are the side boosters using Ti Grid fins, but not the center core?

Elon Musk showed a picture of the almost ready to fly Falcon Heavy in the HIF (Horizontal Integration Facility, aka rocket barn). You can see the darker, larger grid fins on the side cores, and the ...
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1answer
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What is it that SpaceX is editing out of their videos after posting them on YouTube?

Here are two cases where links to a specific time code in SpaceX YouTube videos stop showing the intended moment because apparently SpaceX has gone in within hours or perhaps a day and shortened the ...
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1answer
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Ballpark comparison of a hypothetical Falcon 'Quad' Heavy with cross feeds

This engineering question got me wondering. If cross feed technology were sufficiently developed, and stresses could be managed (these are big if's, and there are more I'm sure), how would these ...
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3answers
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What happens to the Falcon 9 second stage after payload separation?

In a Falcon 9 launch, the second stage looks like it achieves orbit along with the payload. But is that impression accurate? Does SpaceX need to do anything to deorbit the stage? I can see a few ...
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2answers
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How does the Falcon 9 first stage avoid burning up on re-entry?

Now that a Falcon 9 first stage has successfully landed after a launch mission, I want to know how the first stage can avoid burning up when coming back down to earth. There doesn't appear to be any ...
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6answers
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Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?

Yesterday SpaceX succeeded in the first Falcon Heavy launch, but the payload, a Tesla car has no real useful purpose (except for company prestige). Thus, can it be considered as space junk ? How long ...
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Why was AMOS-6 mounted on the rocket for a test fire?

I understand that the static test is a general test of pre-launch procedures, but risking a multi-million dollar payload for a test seems remarkable. Couldn't they use a mass simulator or something? ...
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1answer
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What was the distant bright light in the SpaceX webcast of Orbcomm OG2 deployment?

As I was watching the SpaceX launch today on YouTube, I have noticed a bright distant light as the satellites were being deployed. What was that light? Also, after each deployment there was something ...
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1answer
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How does SpaceX ignite their engines?

Based on the aborted launch on Thanksgiving 2013 of the first Falcon 9 v1.1 from Florida, we know that an issue occurred where oxygen got into the ground based TEA-TEB sources. I understand that TEA-...
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2answers
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Falcon 9 fairings cost and reusability

I read that SpaceX is starting to work on fairings reusability. I couldn't find any information, so I would like to know more about them. In particular, I remember a quote from Musk saying that ...
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Why is Falcon 9's shape so tall and skinny?

Compared to most rockets I know of, Space X's Falcon 9 seems unusually tall and skinny. The v1.1 version is nearly 70m tall, yet only 3.6m thick. For comparison, Atlas V is 58m tall and 3.8m thick, ...
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1answer
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How effective are Falcon 9 1st stage grid fins in the last few seconds before landing?

This answer discusses the three methods that the Falcon 9 1st stage uses for attitude control during re-entry and landing. They are: cold nitrogen jets, "hypersonic" grid fins, and thrust vectoring of ...
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GSLV MK2 vs Falcon 9 - Reasons for Huge performance difference

Yesterday ISRO operated the GSLV MK2 launch vehicle, which is a medium lift launch vehicle with a capability to lift 5 tonnes to LEO. I just compared Falcon 9 with GSLV MK2. Falcon 9 capability to ...
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What would the challenges be in developing a Falcon Heavy with three or four strap-on boosters?

Falcon Heavy has a standard Falcon 9 Full Thrust (FT) rocket core with two strap-on boosters derived from the Falcon 9 FT first stage. What about a heavier Falcon Heavy with four strap-on boosters (or ...
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2answers
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Do 'size of a bus' sized F9 fairings ever float after impact? Are they navigation hazards?

This and this answer describe the Falcon 9 fairings as being quite large, with the payload volume being roughly "the size of a bus" or simply REALLY REALLY big. 13 meters by 4.6 meters and being ...
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1answer
608 views

Is this explanation for the SpaceX 1-Sept-2016 anomaly plausible?

Question: Is this explanation for the SpaceX 1-Sept-2016 anomaly plausible? Or most of it at least (sans LHe)? In the recent New Atlas article SpaceX fingers helium as cause of Falcon 9 rocket ...
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6answers
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Why doesn't Tesla's Roadster melt in space?

Tesla's Roadster is somewhere above us taking sunlight directly part of the time, then very cold on the next half of the orbit. Or when it rolls, one side gets hot, the other is cold. Why don't the ...
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1answer
856 views

How will Sherpa and Formosat-5 be configured as payload and launched?

I was reading the comments in this Reddit and I'm confused. How will Sherpa and Formosat-5 be configured inside the Fairing, and then deployed. One comment seems to suggest that Formosat-5 is one of ...
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2answers
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What computer and software is used by the Falcon 9?

I don't know if this would be public, but what CPU / Microcontrollers are used and what software do they run on the Falcon 9? Do they use an OS or is it just bare metal programming? I found some ...
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Why is SpaceX considering Methane as fuel for their next engine, the Raptor?

Currently, SpaceX has developed the Merlin 1 family (1B (Falcon 1), 1C (Falcon 9 v1.0), 1D (Falcon 9 v1.1/F9-R/Falcon Heavy), vacuum versions and sealevel versions) which are LOX/RP1 based. (75-...
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2answers
10k views

How does the SpaceX Falcon 9 first-stage straighten for landing?

I just saw this video of supposed "SpaceX Rocket Camera Landing Footage Fakery" with over a million views. The narrator repeatedly says it's complete garbage because he doesn't understand and would ...
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2answers
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What is the cost breakdown for a Falcon 9 launch?

I don't know if this was already asked, but I'm very curious about the cost breakdown of a Falcon 9 launch.
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Why did SpaceX attempt to land the booster on a barge instead of somewhere on land?

I understand the benefits of reusability for the rocket booster. But I don't understand why they're landing it on a barge. I've read tons of articles about this but not one has even hinted at an ...
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2answers
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What limits the number of times that a liquid fueled rocket can restart?

I know the upper stage of the Falcon 9 can be restarted once, thus allowing an additional thrust for some circumstances that might require it. However, I don't really understand the mechanism that ...