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42

Scott Manley of the YouTube has a great video that addresses the extra level of the tower, located at the seven minute mark of a recent posting. Verbatim transcript from the video: So pad 39A is where they launched from. An historic pad... saw the launches of Apollo, Space Shuttle, but SpaceX took control of it in 2014 and they began modifying it for ...


23

While this seems lightly ill conceived, it actually makes sense. Super Heavy is going to be very large, as these things go. 70m tall, 9m wide, and while not very dense, still quite heavy. Not very easy to move around. The plan is to land close by to make moving it back to the launch pad easier. Original plan was notionally to land back on the launch ...


17

It's a radar intended to observe nearby boats. Sources: tweet by NASA Spaceflight Reporter Michael Baylor: SpaceX has asked the FCC for permission to operate a Garmin radar on top of a water tower in Boca Chica. The "water tower" looks familiar. FCC filing: Space Exploration Technologies Corp. 0459-EX-CN-2020: ...d) List any natural formations ...


12

The orbital mechanics of satellites are independent from the mass of the satellite. As long as the sats mass is tiny compared to the mass of Earth. The total mass of the ISS is much larger than the mass of the dragon capsule itself, the same is true for the volume and surface of both. So the atmospheric drag of both changes only very little after docking.


12

In order to transmit from a country, one must have a license to do so, with the exception of some spaces without specific owners, like WiFi's 2.4 GHz that allows small narrow transition can work. It is common to have to pay for the bandwidth for each country. Some countries are pickier than others. All that being said, it is perfectly normal and reasonable ...


11

The answer is No, largely based on the fact that India is a signatory to the 1967 Outer Space Treaty. If you pick a country that didn’t sign any of the patchwork of treaties covering space, it could be a slightly different answer. Still, a government can ask, but they might never get paid. But, to India: https://digitalcommons.unl.edu/cgi/viewcontent.cgi?...


9

TL;DR Precise throttling Falcon 9 first stage booster has a tare weight of around 20 tons (IIRC; keep some buffer though) while landing, so it is heavy enough to not perturb due to minor reflected waves from the landing ground provided that it has shed off enough velocity to avoid hard impact. Also, it is a long slender cylinder and not a typical lift ...


8

I don't think there are any papers about it, but here's what I've gleamed from my studies on it. As you mentioned, they use information from the DOD, specifically Space-Track, or C-SPOC, or J-SPOC. They are all really the same thing... Space Track will send out updates when predicted close approaches may happen to the satellite operator. SpaceX somewhere ...


7

It seems NASA likes having two different options for flying humans in space. That's probably why they still have flights booked from Roskosmos. Competition is good. Boeing can probably still engineer the price down.


7

Without the mesh network SpaceX cannot provide global service as originally assumed. A potential (but unsourced) model for what they have is similar to terrestrial mobile internet with ground stations in locations that have good internet access and provide service to a catchment area that reliably has satellites with line of sight to the ground station and ...


7

You are correctly parsing the information. There are two categories of duration. Running on its own power (solar) and other supplies, it can handle a week of free flight as your source indicates. Not sure what the specific limiting factors are. Possibly the solar arrays are not large enough for a complete charge, but are enough in combination with the ...


7

Well, an approach to this is to try and calculate how much power might be needed, and you can make a hack at this. Since I don't know how large the flaps are or various other critical parameters (and I am not sure this information is public) I can't actually calculate what the real power requirements are: rather this answer gives you the expression you need ...


6

What are they? Interstage Umbilical Guillotines I believe they are housings for pyrotechnic separation connections between the falcon 9 second stage and the dragon trunk. I found this NASA document describing the explosive devices on Apollo and the connections you describe look very close to one of the guillotines used on the Lunar Module. Why are there ...


6

http://www.circleid.com/posts/20191230_starlink_simulation_low_latency_without_intersatellite_laser_links/ This study claims that even without the inter satellite laser system, the latency is comparable to land fiber, which often take non-nominal paths. Light travels 31% more slowly in fiber compared to air.


6

Space-X has a completely radical design and testing philosophy. NASA can't ignore it, because it produces results very quickly and costs much less than the traditional model. However, NASA also cannot fully commit to an untested paradigm. More generally, it's smart to diversify your portfolio if you don't know enough to pick the winners. There's also a ...


5

The structure in the picture is the pressure vessel of the Dragon (blue in the picture below). What you have labelled A is the forward section, containing the crew couches. The part labelled B is the aft equipment bay, which stores equipment and supplies (green in the picture below) which are accessible within the cabin. The Crew Dragon is a truncated ...


5

‘Autonomous’ is misleading. The ASDS ships are towed into position by an ocean going tug, and are supported by the Go Quest support ship. Once in landing position, the ASDS operates independently for the landings but then the support ships come in, and the fleet returns to port. It does not appear the ASDS ships are designed to be left at sea unattended ...


4

Not entirely sure of his source, but Scott Manley seems to assume these are portable timers. Timestamp of 5:00 at this Youtube Link.


4

They are hydraulics which initially used an open loop, using kerosene as the working fluid. Some of the initial landing attempt failures were because they ran out of fluid. Closed loop would keep the fluid in the system, open loop dumps it after it is used. When they land, the hydraulics also retract the fins so you can see it is under active control. ...


4

Up to this day, SpaceX stores Falcon 9 rockets horizontally and there are two fundamental reasons for that. First of all, it is much easier to work on lower objects (horizontal rocket) as they test and check each booster before taking it to the launchpad. The second reason is that lower buildings are cheaper and easier to build as their gravity center is ...


4

There are two considerations I would guess motivate the hydrophobic properties of the thermal protection system: The first is protection against the wear of use to increase the lifetime of the material. Falcon 9 encounters high exposure to water from the sea-journey return but also from the Merlin exhaust during re-entry and landing burns. The exhaust of ...


3

An excellent albeit somewhat dated resource for information on rocket engine components is NASA's series of Chemical Propulsion Design Criteria monographs. Here is a (possibly incomplete) list of the monographs related to liquid engine components. All are available on NTRS AFAIK. SP-8048 Liquid Rocket Engine Turbopump Bearings SP-8052 Liquid Rocket Engine ...


3

For starters, no Falcon 9 first stage has flown more than 5 times as of today. It seems that the number of 10 flights (or 11 flights if actually 10 "reuses" are meant, as stated in the question) was a parameter at least in the pre-design phase that for some reasons had to be compromised. I am unaware of any official information about the bottleneck for ...


3

Try SpaceXtract on github. It captures telemetry data directly from the spacex's webcast video feed. From the same author (shahar603), there is also a Telemetry-Data repository containing a collection of telemetry data from spacex past flights.


3

Just wondering, at what level this question is asked? Stability in rockets is an old problem that goes back to the pre-WWII days of Goddard, Oberth, von Braun, and the like. Goddard tried putting the engine at the top, and it didn't help. Rockets need active control. That means: 1) Sensors that tell you how far off you are from the desired state. For ...


3

It would have had been definitely a value to possess some other human rated rocket while Space Shuttle was grounded or later unavailable. This may happen for any rocket.


3

They simply haven't needed it for the testing they've been doing so far. They've been doing single-engine tests and working toward 3-engine tests, and have a lot more work to do before constructing a complete launch pad in Boca Chica. Their planned additions to LC-39A in Florida give some idea of what they will have to build at some point in the future. From ...


3

On a usual aircraft the wings which are redirecting the airflow (and carrying the weight of the aircraft) are mounted firmly to the body. Most control surfaces are already in the direction of the airflow and just redirect it a little. If I understand the proposed Starship landing behavior correctly, those flaps can be almost perpendicular to the flow, so ...


2

Actually it is the opposite. MECO for crew dragon took place sooner as it was lighter. Starlink missions are usually on the edge of the capabilities of Falcon 9 rockets. Each Starlink satellite has a mass of about 260 kg1. Reusable Falcon 9 has a payload limit of 15600 kg. At each Starlink mission, they launch 60 satellites. 60sats*260kg = 15600kg As we can ...


2

Once line of sight is established to the selected docking port, the International Docking System Standard (https://www.internationaldockingstandard.com/) in section 3.5 defines three visual targets that can be used to measure the relative orientation between the spacecraft and the port. There are 3 perimeter reflector targets (PRT) which are retro-...


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