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SpaceX (general discussion)

fredymac

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Is that what they were shooting for?
I'm sure they would have liked more but 8.5 Bar is the 1.4x safety margin over the nominal pressure strength required to meet "man rating" for rockets. I would guess they will continue iterating the design to remove weight without reducing weld strength. At a minimum, they have a weld process that lets them press ahead with Starship prototype integration.
 

sferrin

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Is that what they were shooting for?
I'm sure they would have liked more but 8.5 Bar is the 1.4x safety margin over the nominal pressure strength required to meet "man rating" for rockets. I would guess they will continue iterating the design to remove weight without reducing weld strength. At a minimum, they have a weld process that lets them press ahead with Starship prototype integration.
Makes sense that they would stop once they hit the requirement. There may be other testing they want to do before they do a test to failure.
 

NUSNA_Moebius

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Is that what they were shooting for?
I'm sure they would have liked more but 8.5 Bar is the 1.4x safety margin over the nominal pressure strength required to meet "man rating" for rockets. I would guess they will continue iterating the design to remove weight without reducing weld strength. At a minimum, they have a weld process that lets them press ahead with Starship prototype integration.
As a welder by trade, I'd be interested to know their specific weld process and cross sectional design. If engineered correctly, the welds should not be a point of failure.
 

sferrin

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Is that what they were shooting for?
I'm sure they would have liked more but 8.5 Bar is the 1.4x safety margin over the nominal pressure strength required to meet "man rating" for rockets. I would guess they will continue iterating the design to remove weight without reducing weld strength. At a minimum, they have a weld process that lets them press ahead with Starship prototype integration.
As a welder by trade, I'd be interested to know their specific weld process and cross sectional design. If engineered correctly, the welds should not be a point of failure.
Engineering is only part of it. Weld quality needs to meet the engineering requirements.
 

NUSNA_Moebius

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Is that what they were shooting for?
I'm sure they would have liked more but 8.5 Bar is the 1.4x safety margin over the nominal pressure strength required to meet "man rating" for rockets. I would guess they will continue iterating the design to remove weight without reducing weld strength. At a minimum, they have a weld process that lets them press ahead with Starship prototype integration.
As a welder by trade, I'd be interested to know their specific weld process and cross sectional design. If engineered correctly, the welds should not be a point of failure.
Engineering is only part of it. Weld quality needs to meet the engineering requirements.
Absolutely, though you're not going to reduce weld weight (assuming a very high quality automated process compatible with the scope of the product) without effecting the yield strength in alot of cases hence why I want to know the process and design for their various welds. I imagine alot of the manual welds for Starship will be automated in Mass production increasing quality while reducing excess reinforcement and cost due to the obvious reasons.
 
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kitnut617

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Being a steel fabricator/welder by trade myself, my thoughts are as soon as they get the manufacturing and welding under cover, the weld results will improve dramatically. Being out in the open is not good practice in my view, especially when you're dealing with these high pressure scenarios.
 

Dragon029

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Conventions however do get warped by pointless tradition, laziness and sometimes fiscally-selfish intent.

By going through this sort of process SpaceX is learning valuable data about how to build their vehicles, and they get to identify where convention has brushed over nuggets of gold (like the use of 301 stainless for its unique strength vs temperature properties vs conventional wisdom's 'lighter and stiffer' materials like composites and aluminum alloys).
 

TomcatViP

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Both of you are right IMOHO. Notice also that there is no apparent bracing (ribs and stringers), that would point toward a search for the lowest cost alternative (manufacturing & design) but leaving only, geometry, weld process and sheets thickness as the only variables to play with.
 

sferrin

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Orionblamblam

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A trio of astronomers have called for legal action against the FCC and SpaceX, whose StarLink project, a mega constellation of highly visible communication satellites, has drawn significant ire from astronomers around the globe.
And yet it'll be SpaceX that makes it so that astronomers can build as many telescopes as they want out in space where the seeing is perfect. These astronomers should be helping SpaceX so they can finally start building observatories on Farside.
 

Flyaway

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A trio of astronomers have called for legal action against the FCC and SpaceX, whose StarLink project, a mega constellation of highly visible communication satellites, has drawn significant ire from astronomers around the globe.
And yet it'll be SpaceX that makes it so that astronomers can build as many telescopes as they want out in space where the seeing is perfect. These astronomers should be helping SpaceX so they can finally start building observatories on Farside.
That’s not an equivalent. Anyway what about all the amateur astronomers on the ground, should they be denied the night skies. In my view the night skies are everyone’s right, bad enough we ruin them with light pollution but now this as well.
 

sferrin

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A trio of astronomers have called for legal action against the FCC and SpaceX, whose StarLink project, a mega constellation of highly visible communication satellites, has drawn significant ire from astronomers around the globe.
And yet it'll be SpaceX that makes it so that astronomers can build as many telescopes as they want out in space where the seeing is perfect. These astronomers should be helping SpaceX so they can finally start building observatories on Farside.
That’s not an equivalent. Anyway what about all the amateur astronomers on the ground, should they be denied the night skies. In my view the night skies are everyone’s right, bad enough we ruin them with light pollution but now this as well.
They're not denied. They can still look.

If you want to talk about "rights"? What about my right to keep my money? What about my right to drive without idiots on the road? What about my right to look at the internet without ads? What about my right not to receive spam and junk mail? What about my right to food without having to pay for it? What about my right to not have to deal with dumb people? What about my right not to bombarded by reality shows when I watch TV? Etc., etc. etc.
 

Arjen

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SpaceX regards it as its right to deprive astronomers of a clear view of the stars.
As far as I'm concerned, they might as well consider setting up a 24/7 open air disco next to a hospital.
 
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sferrin

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SpaceX regards it as its right to deprive astronomers of a clear view of the stars.
Not true at all. SpaceX asked for permission to put the satellites up. Permission was given. End of story. (And SpaceX is only one of many to do so.)
 

Arjen

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Permission granted by...? Astronomers all over the world are affected.
 

Orionblamblam

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SpaceX regards it as its right to deprive astronomers of a clear view of the stars.
Where are your complaints about jetliners and city lights and every satellite launched before this? Damn those dirty rotten sailors of five centuries past, spreading western civ across the world! If only they'd stayed home, and the Enlightnenment and the Industrial Revolution had never happened, and the planetary population had stayed in the dark and below a hundred million or so, the night skies would have been *fantastic.*

Bah. SpaceX regards as its right to grant the *universe* to *everyone.* If a clear night sky is your top priority, then get your ass to Mars.
 

Dilandu

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SpaceX regards it as its right to deprive astronomers of a clear view of the stars.
And hunters regard wheat fields as a violation of their rights to hunt wild animals, so what? Who is more important - farmers or hunters? I think it is obvious...

P.S. SpaceX already took some measures to mitigate the effect, like making satellites less reflective.
 

Dilandu

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Permission granted by...? Astronomers all over the world are affected.
1st: And who said that astronomers own the sky?

2nd: What is more valuable: a hobby of some dozen of thousand mens around the globe (because major observatories aren't exactly affected much), or free access to global data, education, entertainment for literally hundreds of millions peoples living outside the First World?
 

Arjen

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@ 1st: Who said SpaceX owns the sky?
@ 2nd: Access cannot be achieved in another way? It's not just amateur astronomers that are affected, professional astronomers are affected as well.

We are looking at competing interests, and I think astronomers are getting a raw deal.
A new paper to be published later this year in the Vanderbilt Journal of Entertainment and Technology Law argues that the Federal Communications Commission—the agency responsible for licensing the operation of these constellations in the U.S.—should have considered the impact these satellites would have on the night sky. In ignoring a key piece of federal environmental legislation, the FCC could be sued in a court of law—and lose—potentially halting further launches of mega constellations until a proper review is carried out.

“Astronomers are having these issues [and think] there’s nothing they can do legally,” says the paper’s author Ramon Ryan, a second-year law student at Vanderbilt University. “[But] there is this law, the National Environmental Policy Act [NEPA, pronounced ‘Nee-pah’], which requires federal agencies to take a hard look at their actions. The FCC’s lack of review of these commercial satellite projects violates [NEPA], so in the most basic sense, it would be unlawful.”


Enacted in 1970, NEPA obligates all federal agencies to consider the environmental impacts of any projects they approve. Such impacts cover a variety of issues, from the effects of casino barges on rivers to any project’s contributions to climate change—the latter has been a recent target of the Trump administration’s regulatory rollbacks. The reviews can take multiple years, producing anywhere from hundreds to thousands of pages of paperwork. Federal agencies can circumvent NEPA, however, if they are granted a “categorical exclusion” for some or all of their activities—usually by arguing that such activities do not impact the environment and thus do not require review. The FCC has had a sweeping categorical exclusion since 1986 across almost all of its activities—including its approval of space projects—despite other agencies involved in space—most notably NASA—being required to conduct NEPA reviews.


“There are other agencies that use categorical exclusions, but I don’t think there is one that’s as broad as this,” says Kevin Bell, staff counsel at Public Employees for Environmental Responsibility (PEER), a nonprofit organization that works with government whistle-blowers on environmental issues. “It is a policy that was designed for another time, before large scale space exploration.”


In light of the concerns about the impacts of satellites on the night sky, Ryan says, this categorical exclusion would be unlikely to stand up in a court of law. SpaceX alone has been licensed by the FCC to launch 12,000 satellites in its Starlink constellation in the coming years, dwarfing the current number of approximately 1,500 active satellites in orbit—and the company has plans for 30,000 more. It has already launched about 180 Starlink satellites, with another 1,500 scheduled for 2020. Following the first launch of 60 satellites in May 2019, many observers were surprised by their brightness at dawn and dusk—popular times for both astronomy and simple stargazing. “That’s the time that most people enjoy the sky,” Hartley says. “These new satellites are brighter than 99 percent of [those] in orbit at the moment. And really, that’s the root of this concern.”
Which, by the way, still leaves the issue of a US institution's decision affecting astronomers outside the USA.
 
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sferrin

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@ 1st: Who said SpaceX owns the sky?
@ 2nd: Access cannot be achieved in another way? It's not just amateur astronomers that are affected, professional astronomers are affected as well.

We are looking at competing interests, and I think astronomers are getting a raw deal.
A new paper to be published later this year in the Vanderbilt Journal of Entertainment and Technology Law argues that the Federal Communications Commission—the agency responsible for licensing the operation of these constellations in the U.S.—should have considered the impact these satellites would have on the night sky. In ignoring a key piece of federal environmental legislation, the FCC could be sued in a court of law—and lose—potentially halting further launches of mega constellations until a proper review is carried out.

“Astronomers are having these issues [and think] there’s nothing they can do legally,” says the paper’s author Ramon Ryan, a second-year law student at Vanderbilt University. “[But] there is this law, the National Environmental Policy Act [NEPA, pronounced ‘Nee-pah’], which requires federal agencies to take a hard look at their actions. The FCC’s lack of review of these commercial satellite projects violates [NEPA], so in the most basic sense, it would be unlawful.”


Enacted in 1970, NEPA obligates all federal agencies to consider the environmental impacts of any projects they approve. Such impacts cover a variety of issues, from the effects of casino barges on rivers to any project’s contributions to climate change—the latter has been a recent target of the Trump administration’s regulatory rollbacks. The reviews can take multiple years, producing anywhere from hundreds to thousands of pages of paperwork. Federal agencies can circumvent NEPA, however, if they are granted a “categorical exclusion” for some or all of their activities—usually by arguing that such activities do not impact the environment and thus do not require review. The FCC has had a sweeping categorical exclusion since 1986 across almost all of its activities—including its approval of space projects—despite other agencies involved in space—most notably NASA—being required to conduct NEPA reviews.


“There are other agencies that use categorical exclusions, but I don’t think there is one that’s as broad as this,” says Kevin Bell, staff counsel at Public Employees for Environmental Responsibility (PEER), a nonprofit organization that works with government whistle-blowers on environmental issues. “It is a policy that was designed for another time, before large scale space exploration.”


In light of the concerns about the impacts of satellites on the night sky, Ryan says, this categorical exclusion would be unlikely to stand up in a court of law. SpaceX alone has been licensed by the FCC to launch 12,000 satellites in its Starlink constellation in the coming years, dwarfing the current number of approximately 1,500 active satellites in orbit—and the company has plans for 30,000 more. It has already launched about 180 Starlink satellites, with another 1,500 scheduled for 2020. Following the first launch of 60 satellites in May 2019, many observers were surprised by their brightness at dawn and dusk—popular times for both astronomy and simple stargazing. “That’s the time that most people enjoy the sky,” Hartley says. “These new satellites are brighter than 99 percent of [those] in orbit at the moment. And really, that’s the root of this concern.”
Which, by the way, still leaves the issue of a US institution's decision affecting astronomers outside the USA.
1. Follow the money.
2. The US isn't the only country putting up large constellations of satellites. The EU is and China almost certainly will. SpaceX just happens to be the first (sortof). Nobody complained about Iridium (not enough to matter anyway).
 

Arjen

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Follow the money - that bypasses all rights discussions. The other bit - two wrongs don't make a right; the issue of launching tens of thousands of satellites is several orders of magnitude bigger than other issues thus far.
 

fredymac

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Sky free of airplanes, land free of roads, ocean free of ships. Just the wrong time to be born if you don't like seeing them. Of course, rain and clouds probably shut down more astronomy observing time than anything else. Winds also muck up the imagery as turbulence smears the light.

In the end the choice comes down to how many people want the services provided by those satellites vs how many would prefer clear skies. If it is an important issue, this will be decided politically and I'm inclined to think the clear skies people won't be happy.
 

Orionblamblam

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@ 1st: Who said SpaceX owns the sky?
Who says amateur astronomers do? If they do, then they should have the right to shut down city, road and car lights at night.

"Ownership" is determined by who can not only lay claim to something, but enforce said claim. I can claim to own Jupiter and demand a $5 royalty fee every time someone looks at it, but I can't enforce that claim... thus it is generally accepted that I don't own Jupiter. SpaceX can go to LEO. Amateur astronomers can't... unless they pay SpaceX to do so. Which they should. Imagine if amateur astronomers, rather than bitching about satellites, were to each buy their own Starlink-sized space observatory. Little space telescopes, maybe 30 cm in diameter, launched into, say 500 km orbits. Controlled via momentum wheels and magnetic stabilization, good for at least 20 years, with terms for easy replacement when the time comes. Instead of complaining, they'd be advancing. Soon such complaints as we're seeing here would be as quaint as people complaining that airplanes making the clouds smell of gasoline.
 

Grey Havoc

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I thought there was a dedicated thread for OneWeb but apparently not. I'll park this here for the moment, since it does impact SpaceX, and set up an OneWeb thread later.

 

Flyaway

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A trio of astronomers have called for legal action against the FCC and SpaceX, whose StarLink project, a mega constellation of highly visible communication satellites, has drawn significant ire from astronomers around the globe.
And yet it'll be SpaceX that makes it so that astronomers can build as many telescopes as they want out in space where the seeing is perfect. These astronomers should be helping SpaceX so they can finally start building observatories on Farside.
That’s not an equivalent. Anyway what about all the amateur astronomers on the ground, should they be denied the night skies. In my view the night skies are everyone’s right, bad enough we ruin them with light pollution but now this as well.
They're not denied. They can still look.

If you want to talk about "rights"? What about my right to keep my money? What about my right to drive without idiots on the road? What about my right to look at the internet without ads? What about my right not to receive spam and junk mail? What about my right to food without having to pay for it? What about my right to not have to deal with dumb people? What about my right not to bombarded by reality shows when I watch TV? Etc., etc. etc.
All of the above are false equivalents as the sky is a free natural resource. Nothing you’ve listed there is an equivalent to that.
 

Flyaway

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@ 1st: Who said SpaceX owns the sky?
Who says amateur astronomers do? If they do, then they should have the right to shut down city, road and car lights at night.

"Ownership" is determined by who can not only lay claim to something, but enforce said claim. I can claim to own Jupiter and demand a $5 royalty fee every time someone looks at it, but I can't enforce that claim... thus it is generally accepted that I don't own Jupiter. SpaceX can go to LEO. Amateur astronomers can't... unless they pay SpaceX to do so. Which they should. Imagine if amateur astronomers, rather than bitching about satellites, were to each buy their own Starlink-sized space observatory. Little space telescopes, maybe 30 cm in diameter, launched into, say 500 km orbits. Controlled via momentum wheels and magnetic stabilization, good for at least 20 years, with terms for easy replacement when the time comes. Instead of complaining, they'd be advancing. Soon such complaints as we're seeing here would be as quaint as people complaining that airplanes making the clouds smell of gasoline.
Well maybe astronomers should have some say in city lighting. It’s not just them that bad lighting impacts but also many animals including humans. Light pollution is an unrealised general menace.
 

Grey Havoc

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We would know street lights as lampposts or light poles here in Ireland. One of the justifications given for replacing traditional street lights (e.g. Low-pressure sodium & HID lamps, the former having been most common in Ireland) with LEDs here & elsewhere during the recent international fad for such was that they would help reduce light pollution. Unfortunately, not only did that ultimately prove not to be the case, but LED street lights in general proved to be far inferior in practice to traditional ones, causing a rise in pedestrian and vehicular accidents, as well as proving a boon for criminal activity. (They also unexpectedly proved more expensive to maintain, wiping out any projected cost savings in procurement [which proved to be a mirage anyway] and power usage.) The law of unintended consequences in action.
 
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