SpaceX (general discussion)

BlueAbyssal said:
Correct. They’re quite large as LEO satellites go.

They don’t use buses in the sense that SpaceX buys a bus and modifies it to suit. They’re custom designs to maximize volume as well as mass; but yes, each version is a different design.
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So no serial builds at all - every unique sat is a boutique build? Really just asking for clarification of the underlying engineering philosophy.
 
martinbayer said:
So no serial builds at all - every unique sat is a boutique build? Really just asking for clarification of the underlying engineering philosophy.
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The opposite. Everything is made on a production line. When they change the type of satellite they are building, they make changes in the design, and change the line.

The overarching design philosophy of SpaceX in general is that line production with a high level of labor specialization produces superior quality and consistency than other production methods, and that things should be made on a line even when it is not economically maximally efficient. The first thing that SpaceX does when they design a new thing (whether it's a satellite or an engine) is to set up the production line, even before they have a design that can be produced. Development happens during line production, with the prototype design being pushed through the line, with necessary design changes made on the line. During design, they often intentionally make lots of defective product that is never intended to be functional, just to keep the line running and build experience for the workers working on the stages that are not going to be changed in the final product.

This is in contrast with many other companies in the business that do hand-crafted prototypes before, or even instead of line construction. The reason for this philosophy is that it keeps unit costs low.
 
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martinbayer said:
So no serial builds at all - every unique sat is a boutique build? Really just asking for clarification of the underlying engineering philosophy.
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Tuna’s explanation is an excellent one. I’m not sure how you got ‘every unique sat is a boutique build’ from my comment, but what I meant was that SpaceX didn’t reuse the V1 design for the V2 Mini, or the V2 Mini for the full-size V2. They’d never be able to afford building thousands if Starlink used boutique satellites.
 
BlueAbyssal said:
Tuna’s explanation is an excellent one. I’m not sure how you got ‘every unique sat is a boutique build’ from my comment, but what I meant was that SpaceX didn’t reuse the V1 design for the V2 Mini, or the V2 Mini for the full-size V2. They’d never be able to afford building thousands if Starlink used boutique satellites.
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Hell, SpaceX is trying to make Starship an assembly line product. To think they wouldn't do that with satellites, that they're making tens of thousands of, makes no sense.
 
I have a silly question if any of you guys know. How close are they layering these constellations to the space above or around Russia and China?
 
TMA1 said:
I have a silly question if any of you guys know. How close are they layering these constellations to the space above or around Russia and China?
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I’ve never looked at the orbital planes Starlink uses, but I do not see how they could not routinely fly over both countries. I think most any LEO orbit would cause that, and certainly thousands of satellites in a global network would have to pass over most every corner of the earth to provide coverage.
 
As much as some people complain about having to rely on a billionaire, it’s undeniable that SpaceX has been a lifesaver in the aftermath of Russia’s invasion. What would the space sector look like if Musk, Shotwell, Mueller et al. had started a taco company instead?
 
TMA1 said:
I have a silly question if any of you guys know. How close are they layering these constellations to the space above or around Russia and China?
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Check it out yourself: https://satellitemap.space/?constellation=starlink (might need a reasonably powerful computer)

Every white dot is an active Starlink satellite. You can click on them for additional information.
 
publiusr said:
On 4.) Buran --and even more so STS orbiters--didn't have much in the way of propellant compared with Starship.

On 3. SuperHeavy does not need to do a burn as Falcon does---let us suppose we lengthen this and incorporate a burn for retropropulsion.

I'm trying to find a way around needing tiles (or even Starship itself) at all. SuperHeavy as reusable Energiya.
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a. stop with the Energiya/Buran comparisons. They were unworkable as 100% reusable. Buran was nothing but a complex fairing. Already have reusable fairings. And can't make Superheavy into an Energiya, there are no side boosters (without side boosters, how can there be a comparison to Energiya?).
b. Can't get rid of tiles, some sort of thermal protection system is required to bring back the orbital stage
c. Can't get rid of Starship, it is the second stage.
d. You are trying to make it more complex. Just forget the orbiter concept that has no propellant for ascent.
4. You need to put more into words, instead of assuming we think like you. Are you saying that because Starship has a more propellant onboard, it is more of a potential orbital debris threat? If, not explains yourself. One of the main purposes of Starship is to deliver propellant to orbit.
 
Forest Green said:
www.twz.com

If SpaceX's Secret Constellation Is What We Think It Is, It's Game Changing (Updated)

A constellation of hundreds of sensor-equipped satellites would offer unprecedented strategic and tactical surveillance around the globe.
www.twz.com www.twz.com
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Wow. Very impressive. Since 1974 when the Soviets first put in service mobile ICBMs (SS-16, SS-24 and SS-25 in the next decade) tracking such rail or road mobile missiles for destruction has been a nightmare. In Cold War days a partial capability was created out of Lacrosse satellites, E-8 JSTAR, plus the cancelled AARS or QUARTZ drone.
35 years later the advent of reusable rockets allowing mega constellations seems to have been a game-changer. After Starlink breakthrough it is no surprise than some NRO core missions are reviewed in the light of large satellite constellations. Same for some airborne missions like E-3 and E-8.
 
Archibald said:
Wow. Very impressive. Since 1974 when the Soviets first put in service mobile ICBMs (SS-16, SS-24 and SS-25 in the next decade) tracking such rail or road mobile missiles for destruction has been a nightmare. In Cold War days a partial capability was created out of Lacrosse satellites, E-8 JSTAR, plus the cancelled AARS or QUARTZ drone.
35 years later the advent of reusable rockets allowing mega constellations seems to have been a game-changer. After Starlink breakthrough it is no surprise than some NRO core missions are reviewed in the light of large satellite constellations. Same for some airborne missions like E-3 and E-8.
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Next step is a constellation of laser-armed satellites to plug said launchers if their angle looks wrong.
 
Tuna said:
The opposite. Everything is made on a production line. When they change the type of satellite they are building, they make changes in the design, and change the line.

The overarching design philosophy of SpaceX in general is that line production with a high level of labor specialization produces superior quality and consistency than other production methods, and that things should be made on a line even when it is not economically maximally efficient. The first thing that SpaceX does when they design a new thing (whether it's a satellite or an engine) is to set up the production line, even before they have a design that can be produced. Development happens during line production, with the prototype design being pushed through the line, with necessary design changes made on the line. During design, they often intentionally make lots of defective product that is never intended to be functional, just to keep the line running and build experience for the workers working on the stages that are not going to be changed in the final product.

This is in contrast with many other companies in the business that do hand-crafted prototypes before, or even instead of line construction. The reason for this philosophy is that it keeps unit costs low.
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Av Week had an article about SpaceX offering to sell laser communications systems developed for its Starlink broadband satellites to third-party satellite manufacturers. Goes along with what you described.

Enjoy the Day! Mark
 
I still think the satellites are possible though, either laser or NPB. It will make a mockery of hypersonics when it finally comes to fruition.
 
Archibald said:
Or space sharks with lasers on their heads !
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Dr.-Evil.jpg
 
Today was 310th launch of Falcon 9.
Bring the 30th Dragon mission to ISS.
and 26th launch this year.

This year Falcon 9 will past the launch numbers of Titan rocket of 368 !
After that is Soyuz with 2000th launches.
SpaceX need 17 years to reach that number (100th/year).
i guess that will be the task of Starship/Superheavy to get those launch number

Estimated date for IFT-4 is May 4, 2024.
 
Fraser Crane posted a few days ago a video where he does an analysis with what happened with IFT-3 with Scott Manley and Marcus House:


Another Test of SpaceX Starship Superheavy combo, another analysis of the flight with Scott Manley and Marcus House!
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00:00 Intro
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00:44 The plan for IFT-3
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02:18 Liftoff and hot staging
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04:34 Booster return
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10:38 Starship in orbit
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17:26 Starship's re-entry
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28:22 More interesting stuff
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33:25 What's next
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36:58 Artemis 3 plans
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43:18 Scott and Marcus
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45:11 Final thoughts
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www.linkedin.com

STARSHIP HEAT SHIELD CONCERNS PERSIST

Perched on top of the Starship rocket prior to IFT3 launch, heat shield tiles are clearly missing in this SpaceX released photo above. This raised serious initial concerns about the integrity of the heat shields contributing to the reentry failure of SpaceX Starship Launch 3 (IFT3) nearly two weeks
www.linkedin.com www.linkedin.com
 
This is the reason I like Columbia type orbiters--yes it had problems too ---I would imagine having TPS on high-volume, flexing tankage is more of an issue
 
publiusr said:
This is the reason I like Columbia type orbiters--yes it had problems too ---I would imagine having TPS on high-volume, flexing tankage is more of an issue
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What says this can't be fixed? Development isn't finished. This is not like the shuttle program where it was persistent.
 
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GTX said:
www.linkedin.com

STARSHIP HEAT SHIELD CONCERNS PERSIST

Perched on top of the Starship rocket prior to IFT3 launch, heat shield tiles are clearly missing in this SpaceX released photo above. This raised serious initial concerns about the integrity of the heat shields contributing to the reentry failure of SpaceX Starship Launch 3 (IFT3) nearly two weeks
www.linkedin.com www.linkedin.com
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"Observers are concerned." *YAWN* Okay. How about we give them a chance to fix the stuff?
 
The tiles here do have some mechanical attachments.....many worried about RTLS aborts of shuttle---how violent they were expected to be.

Yet this is to be expected in EVERY SS/SH flight. That bears remembering.

Could vortices spilling off SS nose fins be the cause of things spalling off?

Could the tiles have the current tesselation but each one have Ford Tri-motor ridges to smooth flow?

Starship is a de facto shuttle replacement (except LS)... perhaps SH could have separate internal tanks on shocks and/or flexible propellant lines like how the shuttle orbiter was fed---lines being exterior to the tanks.

Narrow cores like Falcon might have less concerns with fluid behavior being of thinner construction.

This is why I like stage-and-a-half flight profiles---more gentle on the equipment.
 
publiusr said:
The tiles here do have some mechanical attachments.....many worried about RTLS aborts of shuttle---how violent they were expected to be.

Yet this is to be expected in EVERY SS/SH flight. That bears remembering.
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Wrong. Shuttle RTLS aborts were not "violent". They were just "stressful" for the stack during the flip maneuver.
RTLS was benign for the tile. Less heat load and no different q than a normal mission

publiusr said:
Starship is a de facto shuttle replacement (except LS)... perhaps SH could have separate internal tanks on shocks and/or flexible propellant lines like how the shuttle orbiter was fed---lines being exterior to the tanks.
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No. Too much mass. Ruins mass fraction. No current launch vehicle has tanks separate from outer skin, Propellant lines on the exterior doesn't mean more flexible and it doesn't mean interior ones aren't flexible.

publiusr said:
This is why I like stage-and-a-half flight profiles---more gentle on the equipment.
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Unsupported claim and wrong.

Stage-and-a-half flight profiles don't aid in reusability.

Your priorities are wrong.
Cost is the most important parameter and every trade is done to lower it. Absolute ISP isn't important as cost of ISP. Reusability is a must.
 
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I heard about that. Eric Berger has talked about it and only says it's uncertain what it means so far. Hopefully the flight still happens, but I could also see Maezawa not wanting to wait and canceling it. Alternatively, perhaps he had to put money elsewhere and needed to withdraw for financial reasons.
 
Byeman said:
Your priorities are wrong.
Cost is the most important parameter and every trade is done to lower it. Absolute ISP isn't important as cost of ISP. Reusability is a must.
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Reusability of the SH/SS kind might be its own enemy. As you yourself have said as I recall--rockets are not airplanes.

I just consider stage-and-a-half_to_wet workshop a less stressful form of reusability.

Fly once--retire.

Now you see that as a waste--but if I were to put a voice in the materials, they might prefer the Gene Meyers approach over the Elon Musk approach.

Remember Uri Geller?

He made a name as a mental spoon-bender because he first pre-weakened the spoons by working them back and forth. I am just worried SS/SH aggressive flight profiles will do exactly the same. A century from now? Maybe less a factor as new materials can be had.


Now Uri was thwarted by Carson, who had NEW spoons that hadn't been weakened.

That is what Stage-and-a-half_to_wet-workshop gives you.

Now I have been wrong before--I worried SpaceX would never get all those SH engines to work together--but I was glad to be proved wrong.

Still, just because Falcon has been dialed in doesn't mean SH/SS will work as described.

Unlike Gary Church--I do root for Elon...I just have this gnawing dread something really bad may be about to happen.
 

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