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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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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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1answer
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How will SpaceX Starship deploy its payload?

Most modern orbital launchers like the SpaceX Falcon9 have their payload at the front covered by a fairing which splits in half, ejecting the fairings and exposing the payload for deployment. With ...
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How much fuel would the Starship need to LAND 100,000kg on Earth?

The SpaceX's Starship is in orbit, empty payload. Magically, 100,000kg of payload appears inside the ship, setting aside all the logistical questions of how it got there. Now it needs to deorbit and ...
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Why doesn't the Merlin 1-D use higher LOX to RP-1 mixture ratios?

So I've been screwing around with CEARUN (https://cearun.grc.nasa.gov/), which is the chemical equilibrium with applications program created by NASA. I've been using it to calculate theoretical ISP's ...
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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?
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1answer
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How does SpaceX's Dragon get to the ISS?

How does SpaceX's Dragon capsule get to the ISS? Does Dragon use the onboard Draco thrusters in order to raise its orbit to the station or does the second stage of the Falcon 9 perform the majority of ...
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1answer
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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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1answer
407 views

Why has SpaceX changed Starship from carbon fiber composite to stainless steel?

Recently, there was news that SpaceX changed the material used for the BFS/Starship (upper stage of the BFR) from initially planned carbon fiber to metal which seems quite counter-intuitive as carbon ...
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3answers
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Why is SpaceX not creating its own launch vehicle for small satellites?

With a (predicted) $5.5 Billion dollar market, why isn't SpaceX trying to build its own 'mini launch vehicles'? With the brand and the technology they have, they can easily capture a huge chunk of the ...
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314 views

Why can't SpaceX Starship perform the same landing procedure as the Falcon 9 does?

I know... Elon Musk calls the redesign of the BFR "unintuitive". I'm just trying to get ahead of the Starship introduction and hop test presumably in March/April timeline. But isn't it better to use ...
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1answer
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How does this fast-slewing dish track moving spacecraft?

Very nice video of the antenna, but now some of the interesting bits are covered. At least the music is enjoyable! Elon Musk's recent tweet shows a video clip of a ...
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Where can I find the TLE of ExseedSat 1, India's first ever private LEO satellite?

On 3rd December 2018, a private Indian company Exseed Space launched it's first ever satellite into space called ExseedSat 1. But I couldn't find the TLE for this satellite. I looked it up on n2yo ...
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should spacex have 2 versions of the BFS (sub-orbital city and orbital BFR)? [closed]

The Big Falcon Ship (BFS) has been renamed to Starship. The Big Falcon Booster (BFB) has been renamed to Heavy Booster. Will the sub-orbital version of BFS Starship for Earth to Earth missions, be ...
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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 ...
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Does the 90 million cost for the Falcon Heavy include everything?

SpaceX says that it costs them 90 million each time to launch a Falcon Heavy, does this include fuel? If I where to purchase a Falcon Heavy launch, how much would it cost me to launch it, buying my ...
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1answer
2k views

How much fuel does the Falcon Heavy use? What is the price RP-1?

Does anyone know how much fuel the Falcon Heavy can hold, the RP-1 fuel and liquid oxygen as oxidizer, and how much of that will it use to get to a certain point? I don't know how i would calculate ...
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1answer
87 views

What is the maxium weight the falcon heavy can take to mars

I am doing a project on asteroid mining and I was wondering how much the falcon heavy can take into space, I have seen the Wikipedia page. it says it can take a max of 16.8 metric ton. but at what ...
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Could SpaceX's grid fins be controlled by electric motors instead of hydraulics?

There have been a few instances of landing failures related to the grid fins and their hydraulic control - one where the hydraulic fluid ran out, and the latest one where a hydraulic pump stalled. ...
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1answer
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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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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 ...
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2answers
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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. ...
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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 ...
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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, ...
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What are some drawbacks of Automated Flight Termination Systems (AFTS) sometimes called Automated Flight Safety Systems (AFSS)?

I often read about how AFSS is the the next big part of the range of the future, and how it is a tremendous improvement upon the current system. But I never really read about the drawbacks. No ...
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1answer
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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 ...
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How composite materials used in space tech? [closed]

guys, my name is Muhamed-Kanapiya. Now I am studying at Eurasian National University in Astana, and my specialization is Space vehicles and technologies. My master`s work about using composite ...
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1answer
97 views

Do launch vehicle companies like SpaceX and RocketLab use magnetometers in their IMU units? If not, why?

I am aware that most launch vehicle companies use strapdown IMU systems, consisting of gyros and accelerometers. I was thinking if one could use a magnetometer and accelerometer to get data (like they ...
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1answer
66 views

Actuators for gimbaling of engine in rockets and launch vehicles

For controlling the rockets to stay on course, continuous engine control is require which is done by using gimbal actuators. What type of gimbal actuators have been used on SSME, Rocketlab's ...
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1answer
142 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 ...
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155 views

What is SpaceX's parachute problem that NASA is concerned about in the NASA ASAP report?

The Washington Post's NASA to launch safety review of SpaceX and Boeing after video of Elon Musk smoking pot rankled agency leaders says: Earlier this year, Boeing had a propellant leak during a ...
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109 views

Details about the BFR abort procedures?

What kind of emergency procedures will the BFR have during landings? I can see an abort to an alternate landing zone but what about when you have a an emergency ten seconds after engine shutdown?
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How much noise would the BFR make at launch?

In addition to multi-planetary travel, SpaceX has plans to use the BFR for intercontinental travel. However, would the sound generated by the BFR's launch disrupt local communities and therefore make ...
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Will it be possible to see BFR approaching the moon from earth, with naked eye?

The title pretty much sums it up. I'm not old enough to have experienced any of the previous manned moon landings. Given that Big Falcon Rocket will go around the moon in 2023, I'm wondering if one ...
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1answer
156 views

How low is VLEO? (FCC's newest approval for SpaceX)

Engaget's SpaceX gets FCC approval to deploy thousands more internet satellites says SpaceX's plan to build a global, high-speed wireless internet network using satellites has taken another step ...
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1answer
206 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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69 views

Purging process of a rocket engine

Does spacex purge Falcon 9 engines after landing ? If so, which gas is used for purging?
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175 views

Shape of Dragon Crew capsule affecting ballistic descent?

\ I I don't think anyone has the seen the actual dimensions of dragon version 2, but assuming it is what SpaceX will be using to take people to space, I think it will have issues regarding stability ...
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1answer
228 views

How does falcon-9 engine survive while re-entry burn without chilling ?

I've often seen that in launch sequence, "engine chilldown". I've learnt that chilling is done to avoid thermal cracking in plumbing lines and also to avoid cavitation. While re-entry, do they ...
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Chilling during restart of Spacex first stage engine [duplicate]

As I know that all the liquid rocket engines go through chilling process for different components (like pipes, engine, injector plate, etc.) before starting the ignition. At the time of launch the ...
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2answers
385 views

How does SpaceX plan to make money with StarLink Broadband?

To me, it seems obvious that ground based optical fibres will be cheaper than a space based system by an order of magnitude. So unless say, everyone starts sea-steading and a space based broadband is ...
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1answer
63 views

Can VTVL rockets use dampers like high rise buildings to provide stability?

VTVL with long and thin body have a difficult time in obtaining stability during landing. Watch this failed SpaceX rocket landing for example: Why can't they use "...
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Temperature indicators/labels on space debris?

There was a picture in this question about space debris on shore. Seems to be a part of a Falcon 9. The round stickers are used for temperature control. Similar labels are sold by some companies, for ...
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1answer
148 views

Analytical approximations for the shapes of these plots of ISP vs nozzle diameter? (Raptor engine)

A comment on the currently unanswered question Is there an authoritative catalog for rocket launch identifiers? led me to this Github page which links to r/spacexlounge on which currently appears a ...
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1answer
408 views

Why Elon chose the rocket-launching part of the space market?

The projected future value of the entire market related to spaceflight is Astronomical! I've seen USD 280 billion mentioned for example. The rocket-launching part of that is a small fraction, perhaps ...
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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 ...
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1answer
81 views

Does a retrograde launch impact the return booster propellant requirements, as compared to prograde?

Space-X's latest launch, of SAOCOM-1A, was a retrograde launch from Vandenberg, with a landing back at Landing Zone 4 - at Vandenberg. A retrograde launch requires more energy (to counteract the ...
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1answer
245 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 ...
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1answer
638 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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1answer
240 views

Will SpX-DM1 (Crew Dragon demo mission) carry any useful cargo (supplies)?

To adequately simulate crew transport, the Dragon 2 should at least carry mass simulators of mass equivalent to that of the astronauts. Will it? Will it be dummies or some useful cargo? Would be a ...
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Fuel carried by current Crew Dragon

How much fuel weight will the current Crew Dragon carry? Will it be just enough for launch abort, or the full load (over 3000 lbs) needed for propulsive landing as a back-up to the parachutes? I ...