totm nov 2023 SpaceX Discussion Thread

[sh1pman]

8 minutes ago, CatastrophicFailure said:

Holey mother of Kessler... 

Maybe Starlink is a prototype for Dyson Swarm. 

[CatastrophicFailure]

38 minutes ago, sh1pman said:

Maybe Starlink is a prototype for Dyson Swarm. 

Forget Starship, they keep this up and pretty soon one could simply walk to space... 

cue Stairway to Heaven...

[Delay]

R.I.P. Space travel. 42,000 in LEO?

 

That's around one satellite per kilometer on the equator!

Edited October 16, 2019 by Delay

[Xd the great]

6 minutes ago, Delay said:

R.I.P. Space travel. 42,000 in LEO?

 

That's around one satellite per kilometer on the equator!

Not all 42000 satellites are on the equator.

[Delay]

Just now, Xd the great said:

Not all 42000 satellites are on the equator.

Even the most inclined orbit crosses the equator twice.

[Raven Industries]

I sort of think that so many satellites might be a long term positive. If we're to keep up with the whole space thing, eventually we need to learn how to deal with debris, space junk, and high traffic in orbit. Maybe Starlink will give projects to deal with that sort of thing a good kick towards becoming more viable. 

[zolotiyeruki]

My understanding is that Starlink satellites will be low enough that without occasional boosts, their orbits will decay relatively quickly, so the risk of Wall-E isn't as great as it might initially appear.

[Raven Industries]

Although a WALL-E situation would lead to the fascinating if strange combination of rocketry and snowplow technology. 

[kerbiloid]

Looks like under the "link" they mean a "strut".

4 hours ago, CatastrophicFailure said:

Forget Starship, they keep this up and pretty soon one could simply walk to space... 

Starship will break holes in the net. Then it will self-repair.

P.S.
Should we now return the separated thread about Starlink Kessler back to the main thread merge this thread to the main thread about the Starlink Kesselr?

P.P.S.
Are Musk Borg?

Edited October 16, 2019 by kerbiloid

[magnemoe]

9 hours ago, Xd the great said:

Not all 42000 satellites are on the equator.

Surface area if earth is around 5*10^9 km^2, 42.000 gives each 120.000 km^2 or an 346 km sized square. 
Yes that would be an decent coverage  

 

[Rakaydos]

4 hours ago, magnemoe said:

Surface area if earth is around 5*10^9 km^2, 42.000 gives each 120.000 km^2 or an 346 km sized square. 
Yes that would be an decent coverage  

 

AS far as kesseler effects are concerned, they are also in multiple shells, with a total thickness hundreds of KM deep. That's a lot of volume to miss another satellite in.

[Elthy]

We have a thread for that specific topic:

 

Edited October 16, 2019 by Elthy

[CatastrophicFailure]

 

[mikegarrison]

Falcon Heavy is not human-rated, though.

[sevenperforce]

19 minutes ago, mikegarrison said:

Falcon Heavy is not human-rated, though.

The Artemis program does not require launching humans on commercial LVs. Duties for commercial vehicles in Artemis are limited to component lift only.

[RealKerbal3x]

19 minutes ago, mikegarrison said:

Falcon Heavy is not human-rated, though.

It doesn't need to be. FH's role in Artemis would probably be to deliver the lunar lander (or elements of it) to the Moon.

[tater]

FH isn't human rated, but it has flown 3 flights more than SLS.

Wonder how many it would have to fly to be as "man rated" as Soyuz is? (since NASA has none of the data on that that they'd require if it was a US LV).

[magnemoe]

38 minutes ago, tater said:

FH isn't human rated, but it has flown 3 flights more than SLS.

Wonder how many it would have to fly to be as "man rated" as Soyuz is? (since NASA has none of the data on that that they'd require if it was a US LV).

Good point especially since falcon 9 and heavy is very similar from the dragon capsule point of view. 
The most dangerous event for an dragon capsule is an upper stage RUD. (outside of the dragon blowing up obviously :)) but none are affected by first stage or boosters much. 
One issue I see is if one booster shut down but second booster continue to trust this would jaw the rocket and make it break up because of air resistance. 
However this is more an KSP issue, in real life you cut engines and abort if parts loose connection to each others. You have both redundant data links and also break wires who detect hull breach. 
This was activated during an Apollo launch abort test who ended up being an real abort so an very good test even if an fail  
 

[tater]

3 minutes ago, magnemoe said:

Good point especially since falcon 9 and heavy is very similar from the dragon capsule point of view. 

Assuming they get their act together regarding commercial crew, it seems like FH should be as man-rated as F9, as the components are all the same. Wonder how maxq differs?

[.50calBMG]

Just now, tater said:

Assuming they get their act together regarding commercial crew, it seems like FH should be as man-rated as F9, as the components are all the same. Wonder how maxq differs?

Presumably it starts sooner because IIRC Falcon Heavy has a TWR of close to 2 at liftoff, and it is going faster through a denser part of the atmosphere.

[magnemoe]

Just now, tater said:

Assuming they get their act together regarding commercial crew, it seems like FH should be as man-rated as F9, as the components are all the same. Wonder how maxq differs?

They can cut engines on core to reduce it, this would require restart capability of more engines who is not an major issue. 
Now one issue might be that you need an hypergolic 3rd stage to replace the trunk for an moon mission. Now you could solve this multiple ways like having that part as an separate core who stay in second stage or was dropped 0.1 second after abort but probably my main issue here. 

[sevenperforce]

3 minutes ago, tater said:

Assuming they get their act together regarding commercial crew, it seems like FH should be as man-rated as F9, as the components are all the same. Wonder how maxq differs?

Abort works almost exactly the same way (higher MaxQ probably isn't an issue) so it would be a question of abort odds rather than abort risk.

Abort is not a low-risk scenario; even in an abort, there are potential problems. If we suppose that 95% of aborts will be successful, then the booster needs to be 93% reliable in order to put LOCV risk at better than 1/270. If 98% of aborts will be successful, then the booster needs to be 82% reliable to meet the same standard.

Man-rating Falcon Heavy would require a showing that it is at least as reliable as Falcon 9, or in any event close enough that LOCV risk remains acceptable.

[tater]

1 minute ago, magnemoe said:

They can cut engines on core to reduce it, this would require restart capability of more engines who is not an major issue. 
Now one issue might be that you need an hypergolic 3rd stage to replace the trunk for an moon mission. Now you could solve this multiple ways like having that part as an separate core who stay in second stage or was dropped 0.1 second after abort but probably my main issue here. 

Lunar use with Crew Dragon would be... yeah, a lot more complex. Needs a SM, etc.

[Thor Wotansen]

It would be easier to launch a separate service module on the FH and then launch a Dragon on a F9 to dock in LEO before going on to the Moon.  The 30ish tons of payload should be enough for a service module to put a Dragon around the moon and back.

[sevenperforce]

3 minutes ago, Thor Wotansen said:

It would be easier to launch a separate service module on the FH and then launch a Dragon on a F9 to dock in LEO before going on to the Moon.  The 30ish tons of payload should be enough for a service module to put a Dragon around the moon and back.

Arguably even more efficient to give Dragon a 10-tonne service module (maybe docked to an IDA inside the trunk?) and use FHUS residuals to do the TLI.

Dragon 2 is not really great for lunar ops though. Not enough space or capability to really do anything other than go and return. Would be fine if you had LOP-G though.