Author Topic: Starship all weather launch capability  (Read 24593 times)

Online steveleach

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Starship all weather launch capability
« on: 03/23/2021 07:18 am »
If SpaceX are "aiming for three flights a day for a Starship" then they are presumably going to have to be able to launch in pretty much any weather.

I can imagine them having "weather pathfinder" launches where they deliberately launch tankers in slightly worse weather than their previous record in order to gather data, for example.

Nathan's article at https://www.nasaspaceflight.com/2020/05/why-weather-rules-exist/ is a good read on the reasons for current weather restrictions, but in the future world of Starship they are going to have to work around most of these things. The fact that a launch of some vehicle somewhere once failed due to a particular weather-related problem is no longer going to be allowed to get in the way.

What are the key challenges going to be, and what options are available to deal with them? What weather problems will Starship have to face that commercial airliners don't routinely deal with?

Offline Alberto-Girardi

Re: Starship all weather launch capability
« Reply #1 on: 03/23/2021 07:43 am »
If SpaceX are "aiming for three flights a day for a Starship" then they are presumably going to have to be able to launch in pretty much any weather.

I can imagine them having "weather pathfinder" launches where they deliberately launch tankers in slightly worse weather than their previous record in order to gather data, for example.
I think nobody has done this because why to risk a rocket anfìd a payload, and nobody wants to use a an expensive  only to test. Spacex could do this with starship
Quote


Nathan's article at https://www.nasaspaceflight.com/2020/05/why-weather-rules-exist/ is a good read on the reasons for current weather restrictions, but in the future world of Starship they are going to have to work around most of these things. The fact that a launch of some vehicle somewhere once failed due to a particular weather-related problem is no longer going to be allowed to get in the way.

What are the key challenges going to be, and what options are available to deal with them? What weather problems will Starship have to face that commercial airliners don't routinely deal with?

airliner can avoid the core of the storm, rockets can't.
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Offline Gooden

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Re: Starship all weather launch capability
« Reply #2 on: 03/23/2021 07:56 am »
If SpaceX are "aiming for three flights a day for a Starship" then they are presumably going to have to be able to launch in pretty much any weather.

I can imagine them having "weather pathfinder" launches where they deliberately launch tankers in slightly worse weather than their previous record in order to gather data, for example.
I think nobody has done this because why to risk a rocket anfìd a payload, and nobody wants to use a an expensive  only to test. Spacex could do this with starship
Quote


Nathan's article at https://www.nasaspaceflight.com/2020/05/why-weather-rules-exist/ is a good read on the reasons for current weather restrictions, but in the future world of Starship they are going to have to work around most of these things. The fact that a launch of some vehicle somewhere once failed due to a particular weather-related problem is no longer going to be allowed to get in the way.

What are the key challenges going to be, and what options are available to deal with them? What weather problems will Starship have to face that commercial airliners don't routinely deal with?

airliner can avoid the core of the storm, rockets can't.

Storm Ahead! Turn right!...
Yeep that would be a little dificult! xD maybe Elon will find a way to control weather and then problem solve!

Offline Alberto-Girardi

Re: Starship all weather launch capability
« Reply #3 on: 03/23/2021 08:12 am »
If SpaceX are "aiming for three flights a day for a Starship" then they are presumably going to have to be able to launch in pretty much any weather.

I can imagine them having "weather pathfinder" launches where they deliberately launch tankers in slightly worse weather than their previous record in order to gather data, for example.
Quote
I think nobody has done this because why to risk a rocket anfìd a payload, and nobody wants to use a an expensive  only to test. Spacex could do this with starship


I think this is son of the extreme reliability launch policy by companies. You don't want to lose a rocket, expecially when after a single failure nobody will  want to launch with you (or you will need to lower the cost), or at least will look you suspicius. Apollo 12 was launched in the middle of a storm, and survived. But it is always better to not risk. Scrubs are better than failures. (expecially if NASA is involved, if a f9 fails NASA will imediatly look if there is risk for future crew flights.


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Online steveleach

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Re: Starship all weather launch capability
« Reply #4 on: 03/23/2021 08:58 am »
But it is always better to not risk.
That was the old way, and SpaceX are going to have to find a new way if they are going to meet
their goals.

We have to bear in mind that the majority of Starship flights are going to be tankers, so the risk appetite is going to be very different to anything we've seen previously.
Quote
Scrubs are better than failures.
Yes, but how many scrubs are better than one failure? To argue in extremis, if you scrub every launch then you'll never have a failure. Clearly there has to be some level of risk acceptance.

Online steveleach

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Re: Starship all weather launch capability
« Reply #5 on: 03/23/2021 09:05 am »
airliner can avoid the core of the storm, rockets can't.
Good point there, though presumably there are multiple trajectories that could reach orbit, if you allow for a bit of payload reduction.

Something like launching tankers only 80% full so they can stay vertical longer and fly most of the trajectory at a greater altitude than normal to stay above the weather.

Also, I suspect that commercial launch Starships will rarely launch with anything close to their maximum payload. Schedule delays will often cost more than payload efficiency.

Offline Dave G

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Re: Starship all weather launch capability
« Reply #6 on: 03/23/2021 10:28 am »
If SpaceX are "aiming for three flights a day for a Starship" then they are presumably going to have to be able to launch in pretty much any weather...

Excellent point, and interesting thread.

I'm starting to think about this from a different angle.  For example, what limits them to 3 flights a day?  Could they squeeze in 4 on a good day? The following quote from SpaceX could be interpreted that way, maybe...
Quote from: SpaceX lead manufacturing engineer Jessica Anderson
The design goal for Starship is 3 flights per day on average, which equates to roughly 1000 flights per year, at greater than 100 tons per flight. This means every 10 ships would yield 1 megaton per year to orbit.

But I suspect a better way to look at this quote is "roughly 1000 flights per year".
Running with that, 3 * 365 = 1095 possible flight opportunities per year,
so maybe around 10% of the time they plan not to launch due to poor weather or other issues.

Obviously, since we're talking about SpaceX goals here, they may be somewhat optimistic,
but we're hearing these sorts of numbers from multiple people within SpaceX,
so it's also obvious they've given this some thought, and I'm interested in their thinking.

So let's say they're willing to risk launching some payloads in "bad weather" but not "very bad weather",
where "very bad weather" only occurs 10% of the time.

For example, it seems like Mars missions will require 5 tanker launches for every crew or cargo launch.
In other words, 83% of launches for Mars missions will just be launching propellant, no payload.
Now couple that with SpaceX's goal of ramping up production to manufacture a Starship every 72 hours (link here).
In this light, maybe launching in bad weather isn't that much of a risk...

Offline Jim

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Re: Starship all weather launch capability
« Reply #7 on: 03/23/2021 11:11 am »
The fact that a launch of some vehicle somewhere once failed due to a particular weather-related problem is no longer going to be allowed to get in the way.


Not true.  They will always be susceptible to lightning, winds aloft and ground winds.

Offline Jim

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Re: Starship all weather launch capability
« Reply #8 on: 03/23/2021 11:15 am »

We have to bear in mind that the majority of Starship flights are going to be tankers, so the risk appetite is going to be very different to anything we've seen previously.


Not really.  This isn't a war, where there are acceptable losses.  There isn't going to be a readily available production replacements.  Also, delays are still cheaper than replacing hardware.  Tankers falling out of the sky or blowing up on the pad will still be frowned upon.

Risk "appetite" increases with tankers only when you use expendable vehicles. With reusable, the vehicle costs more than the cargo and the risk "appetite" decreases

« Last Edit: 03/23/2021 11:20 am by Jim »

Offline JamesH65

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Re: Starship all weather launch capability
« Reply #9 on: 03/23/2021 01:24 pm »
Although SX may aim for an average of 3 per day, I cannot see that meaning they will launch in unfavourable conditions. There seems not point at all in risking anything just to reach some arbitrary launch rate.

Of course, they may design such that they can launch in more difficult conditions than now, but as Jim says there are always going to be circumstances where you simply don't launch as the risk is not worth it. And I cannot see them wanting to change design too much just to allow them more launch opportunities. It would almost certainly involve a drop in payload.

Offline schuttle89

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Re: Starship all weather launch capability
« Reply #10 on: 03/23/2021 01:32 pm »
I would think that initially they will stay very conservative with launch parameters so they have as close to an impeccable record as possible and get as much data as possible. Eventually you might see some sightly risky launches then maybe after thousands of launches you'll see some that would scrub any other rocket but where they understand the parameters so well that it is actually very low risk. But they'll never launch during a hurricane or something very crazy as why risk your hardware.

Offline Barnalby

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Re: Starship all weather launch capability
« Reply #11 on: 03/23/2021 01:33 pm »
The Russians have no problem launching Soyuz in all manner of awful weather and it has a near-flawless safety record to show for it.  Surely it can't be impossible if they're doing it.

Offline chopsticks

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Re: Starship all weather launch capability
« Reply #12 on: 03/23/2021 01:42 pm »
It seems like landing actually might be more of a concern than launch, another factor that other launch providers don't have to worry about. It seems like Starship could be rather susceptible to wind on the way down, however, this is already known given that Elon has mentioned hot gas thrusters to compensate for high winds. I guess we'll see what happens.

Offline RonM

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Re: Starship all weather launch capability
« Reply #13 on: 03/23/2021 01:47 pm »
The Russians have no problem launching Soyuz in all manner of awful weather and it has a near-flawless safety record to show for it.  Surely it can't be impossible if they're doing it.

They don't have the thunderstorm and lightning issues that the Florida and Texas coasts have.

Offline rakaydos

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Re: Starship all weather launch capability
« Reply #14 on: 03/23/2021 02:04 pm »
The fact that a launch of some vehicle somewhere once failed due to a particular weather-related problem is no longer going to be allowed to get in the way.


Not true.  They will always be susceptible to lightning, winds aloft and ground winds.
I would think the stainless hull would provide some faraday protection from lightning strikes, at least for important systems.

Offline Barnalby

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Re: Starship all weather launch capability
« Reply #15 on: 03/23/2021 02:07 pm »
They launch in those conditions as well.  It mostly has to do with the fact that the Soyuz family of boosters has its origins in the R-7 ICBM and it's, uhhh, "not really acceptable" to have an ICBM system that can be scrubbed because of bad weather.  Real "screen door on a submarine" energy.

Lack of all-weather launches in the west is mostly a function of the pathological risk-aversiveness that permeates NASA and western spaceflight in general and it's that pathological risk-aversiveness that has so hindered our expansion into the cosmos that SpaceX is trying so hard to move away from.

Soyuz can night launch astronauts to the ISS in whiteout blizzard conditions while NASA scrubs due to high altitude wind shear on otherwise clear days.  If SpaceX wants to hit their launch cadence targets for Starship, it's going to need to be able to safely launch during snowfall and tropical storms, etc.

Offline butters

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Re: Starship all weather launch capability
« Reply #16 on: 03/23/2021 02:11 pm »
The capability to launch multiple times a day will make the tanker campaigns more resilient to weather constraints because they'll be able to squeeze more launches in to the acceptable weather windows.

Offline Lars-J

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Re: Starship all weather launch capability
« Reply #17 on: 03/23/2021 02:47 pm »
Why do people transform "aiming for three flights a day for a Starship" into "aiming for three flights a day for a Starship WEATHER BE DAMNED!"? It makes no sense.

It doesn't make sense. Envelopes will be expanded eventually, but bad weather can still ground commercial aircraft, even though they are designed to spend the majority of the time in the air.

Nobody (including SpaceX) will risk a reusable craft in this way just because someone way back said that we should be able to fly three flights per day.
« Last Edit: 03/23/2021 02:49 pm by Lars-J »

Offline Jim

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Re: Starship all weather launch capability
« Reply #18 on: 03/23/2021 02:58 pm »
1.  They launch in those conditions as well.  It mostly has to do with the fact that the Soyuz family of boosters has its origins in the R-7 ICBM and it's, uhhh, "not really acceptable" to have an ICBM system that can be scrubbed because of bad weather.  Real "screen door on a submarine" energy.

2.  Lack of all-weather launches in the west is mostly a function of the pathological risk-aversiveness that permeates NASA and western spaceflight in general and it's that pathological risk-aversiveness that has so hindered our expansion into the cosmos that SpaceX is trying so hard to move away from.

Soyuz can night launch astronauts to the ISS in whiteout blizzard conditions while NASA scrubs due to high altitude wind shear on otherwise clear days.  If SpaceX wants to hit their launch cadence targets for Starship, it's going to need to be able to safely launch during snowfall and tropical storms, etc.

not true

1.  Atlas and Titan were ICBMs and still had those constraints.   Soyuz doesn't not launch in the thunder storms like in Florida.  Soyuz in Kourou doesn't launch in them.

2. just an inane comment.  The constraints haven't changed in decades.  It has nothing to do with " pathological risk-aversiveness".  Nor has it hindered "our expansion into the cosmos "

3.   High altitude wind shear is only happens on clear days.  It is the reason for clear days.   

Launch probability (wind shear) and launch vehicle performance is a trade.  It is one or the other.


 Airliners don't fly in tropical storms.   Airliners aren't serviced in lightning storms.  Airliners can't even taxi to gates in lightning storms since ground crews are not allowed outside.

« Last Edit: 03/23/2021 03:12 pm by Jim »

Offline Zardar

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Re: Starship all weather launch capability
« Reply #19 on: 03/23/2021 03:26 pm »
In the future, when "Mission Success" involves launching a Deep Space Transport (starship) into LEO, followed by ~10 tankers (plus a few spares) in rapid succession into the same plane, expecting the weather (and GSE!) to cooperate for a dozen opportunities (possibly over a week or two in real-time), is probably an excessive amount of mission risk.

Perhaps instead of overengineering the Rockets and Launch Infrastructure to rapidly return, restack and refly a small number of craft from the same pad, a better option to assure success might be to set up a "Rocket Row", with shared cranes/service towers, and launch them all over a couple of successive launch windows once the weather is favourable.

On this scale of things, concrete and rebar (for SpaceX style launch pads) is cheap, and their in-house GSE tankage is cheap too. At least compared to deep space missions repeatably scrubbed or aborted due to weather or GSE delays.

Although I do acknowledge that getting control and permission of multiple miles of coastline to setup and use such a Rocket Row might be an issue, one that would require Government support to overcome.

Tags: Starship weather 
 

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