Skylon

SpaceX Discussion Thread

Recommended Posts

8 minutes ago, CatastrophicFailure said:

Holey mother of Kessler... :blink:

Maybe Starlink is a prototype for Dyson Swarm. 

Share this post


Link to post
Share on other sites
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... :wacko:

cue Stairway to Heaven...

Share this post


Link to post
Share on other sites

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

 

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

Edited by Delay

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
Just now, Xd the great said:

Not all 42000 satellites are on the equator.

Even the most inclined orbit crosses the equator twice.

Share this post


Link to post
Share on other sites

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. 

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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 by kerbiloid

Share this post


Link to post
Share on other sites
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 :) 

 

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

We have a thread for that specific topic:

 

Edited by Elthy

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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).

Share this post


Link to post
Share on other sites
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 :) 
 

Share this post


Link to post
Share on other sites
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?

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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. 

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.