totm nov 2023 SpaceX Discussion Thread

[PB666]

45 minutes ago, Nightfury said:

Would be an idea, but if you want to have some scientific data coming from these later, it would be good if they make it into orbit

What about a satellite made of 1" thick titanium designed to survive an explosion and reentry that documents UDE it could have little tiny force wires attached to the payload fairing documenting the forces of take-off, the event, temperature sensors that document the heat, three dimensional accelerometer, a small gyroscope that allows it to orient itself during a fall. Of course it would have to have a very durable battery and a transponder to tell everyone where it landed.

[Nightfury]

6 minutes ago, PB666 said:

What about a satellite made of 1" thick titanium designed to survive an explosion and reentry that documents UDE it could have little tiny force wires attached to the payload fairing documenting the forces of take-off, the event, temperature sensors that document the heat, three dimensional accelerometer, a small gyroscope that allows it to orient itself during a fall. Of course it would have to have a very durable battery and a transponder to tell everyone where it landed.

Thats a awesome idea

[DAL59]

 

[Serpens Solidus]

Awesome footage of the launch including the entry burn.

[Nightfury]

Oh totally forgot:

R.I.P B1036

[Just Jim]

10 minutes ago, Serpens Solidus said:

Awesome footage of the launch including the entry burn.

I've been watching the news this morning, and it appears Los Angeles had quite a "War of the Worlds" moment when this went over... lmao.... 

Edited December 23, 2017 by Just Jim

[IncongruousGoat]

43 minutes ago, Serpens Solidus said:

Awesome footage of the launch including the entry burn.

That is really, really cool.

33 minutes ago, Just Jim said:

I've been watching the news this morning, and it appears Los Angeles had quite a "War of the Worlds" moment when this went over... lmao.... 

Do you have a link to an article about that?

[Just Jim]

4 minutes ago, IncongruousGoat said:

Do you have a link to an article about that?

Here's one of them... they don't actually use the words "War of the Worlds"... I was paraphrasing... But from the sounds of it, for a few minutes the Los Angeles 911 boards were lighting up with people reporting a huge UFO...

Orson Wells would have been so proud... 

https://www.yahoo.com/lifestyle/southern-california-thought-saw-ufo-035547261.html

[Green Baron]

The theme has been set to music as well.

"The chances of anything coming from Mars are a million to one, he said" could be reformulated as

"The chances of Elon Musk going to Mars ...."

[NSEP]

1 hour ago, Serpens Solidus said:

Awesome footage of the launch including the entry burn.

Some people even mistook it as a UFO.

Anyways heres a vid

 

[Starman4308]

17 minutes ago, Just Jim said:

Here's one of them... they don't actually use the words "War of the Worlds"... I was paraphrasing... But from the sounds of it, for a few minutes the Los Angeles 911 boards were lighting up with people reporting a huge UFO...

Orson Wells would have been so proud... 

https://www.yahoo.com/lifestyle/southern-california-thought-saw-ufo-035547261.html

The end of that Yahoo article says "we could use some warning next time".

People. Please. This was announced hugely in advance. You live close to Vandenburg. The only difference this time was that atmospheric and lighting conditions produced an unusually spectacular contrail. You have only yourselves to blame for not caring about launch schedules or checking if there was a launch from Vandenburg.

[_Augustus_]

1 hour ago, Just Jim said:

I've been watching the news this morning, and it appears Los Angeles had quite a "War of the Worlds" moment when this went over... lmao.... 

It boggles the mind how little most people look up or read about space exploration. I've met people that think that we've already discovered (unintelligent) aliens, gone to Mars, built a base on the Moon, etc. or that think that the Shuttle is still flying. Then they complain about how they weren't warned about this launch.

Edited December 23, 2017 by _Augustus_

[sevenperforce]

Tons of conspiracy theorists waxing eloquent, including a surprising number of celebrities. You always have this idea that celebrities ought to be a LITTLE more aware than the general public, but noooooo.

"Satellite?! I don't buy it. If it was a satellite they would have announced it ahead of time."

Right....

Anyway, I was thinking...in a way, the notion of dumping a booster into the ocean on its second flight, even when it COULD be recovered, validates the economics of reuse. It's one thing to develop a massive system for recovering boosters, but recovery alone doesn't mean reuse is economical -- just look at the Space Shuttle. However, if reuse has progressed to the point that a business can make a profit-and-loss assessment where they decide to expend a reused booster, then OBVIOUSLY reuse is working, because those kinds of profit-and-loss decisions wouldn't be made if the goal was reuse for reuse's sake.

Any news on the fairing recovery?

[kerbiloid]

Are they going to sterilize the whole car? With all rubber details, cracks, meshes?

Or this is a secret plan of the Earth life expansion?

[sevenperforce]

2 minutes ago, kerbiloid said:

Are they going to sterilize the whole car? With all rubber details, cracks, meshes?

Or this is a secret plan of the Earth life expansion?

The Roadster is not going to intersect anything for a billion years or so.

[kerbiloid]

3 minutes ago, sevenperforce said:

if reuse has progressed to the point that a business can make a profit-and-loss assessment where they decide to expend a reused booster, then OBVIOUSLY reuse is working, because those kinds of profit-and-loss decisions wouldn't be made if the goal was reuse for reuse's sake.

Unless the reusability begins making sense only for very huge rockets.

[cubinator]

2 minutes ago, kerbiloid said:

Are they going to sterilize the whole car? With all rubber details, cracks, meshes?

Or this is a secret plan of the Earth life expansion?

I think they find it unlikely enough that the car will hit any planets (~1,000,000,000 y) before we go out and spread ourselves anyway (~50-100 y) that it's ok.

Edited December 23, 2017 by cubinator

[kerbiloid]

2 minutes ago, sevenperforce said:

The Roadster is not going to intersect anything for a billion years or so.

 

1 minute ago, cubinator said:

I think they find it unlikely enough that the car will hit any planets before we go out and spread ourselves anyway that it's ok.

Then I suggest to put a sandwich in its glove box.

Edited December 23, 2017 by kerbiloid

[sevenperforce]

4 minutes ago, kerbiloid said:

Unless the reusability begins making sense only for very huge rockets.

The key is that they chose to expend a reused booster.

The main thing detractors say about SpaceX's reuse program is that it's all a gimmick: that Elon is just obsessed with reuse, that it's all a big waste of resources, that expendable rockets will always be more capable, more reliable, and ultimately more economical.

Simply recovering a booster doesn't combat this idea, because you haven't shown that you can reuse it. Continuing to occasionally expend new rockets on high-energy missions doesn't, either. Even reflying used rockets could still be said to be just the pursuit of an idea, more trouble than it's worth, that sort of thing. But once the program has progressed so far that SpaceX decides to expend a reused booster, then it's obvious that A) reuse is working, and B) their decisions are being driven by business acumen and not just a crazy idea.

 

[Jaff]

I kind of see what you’re saying.

 

i didn’t think of the expense of the logistics of recovering the booster. It’s costly to recover using drone ship, crane, truck etc. Just to get it back and strip it down because the block 3 isn’t meant to be reused more than once. 

 

Still doesnt answer why they had fins on it unless they wanted to bin it in a specific place. In which case it makes sense that they used a dirty old interstage with crappy alu fins.

id have imagined the engines would be worth recovering no matter what though 

[tater]

They likely did some sort of testing we are not meant to be aware of on the return flight. Not everything needs to be telegraphed to competitors, after all.

[zolotiyeruki]

I don't know if this is the right thread to post this, but...

 

So they deployed 10 satellites, and all separated from Stage 2 at very low speeds.  So that means all the satellites will basically be orbiting as a group, at least in the near term.  Or are there some sort of thrusters/engines on the satellites so they can push themselves into different orbits?  How does it work to launch a constellation of satellites?

Edited December 23, 2017 by zolotiyeruki

[cubinator]

1 minute ago, zolotiyeruki said:

I don't know if this is the right thread to post this, but...

 

So they deployed 10 satellites, and all separated from Stage 2 at very low speeds.  So that means all the satellites will basically be orbiting as a group, at least in the near term.  Or are there some sort of thrusters/engines on the satellites so they can push themselves into different orbits?  How does it work to launch a constellation of satellites?

Each satellite gives itself a tiny push in the appropriate direction, and slowly they spread out within the orbital plane. 

[sevenperforce]

10 minutes ago, zolotiyeruki said:

I don't know if this is the right thread to post this, but...

So they deployed 10 satellites, and all separated from Stage 2 at very low speeds.  So that means all the satellites will basically be orbiting as a group, at least in the near term.  Or are there some sort of thrusters/engines on the satellites so they can push themselves into different orbits?  How does it work to launch a constellation of satellites?

Stage 2 wasn't in a perfectly circular orbit, so each satellite was nudged in a slightly different direction, at a slightly different release speed. Thus, even though all the sats have essentially the same orbital period, they will slowly drift apart.

And yes, they each have thrusters (hydrazine, probably) for station-keeping. All commercial sats have to be able to control themselves. These thrusters will be used to fix their orbits once they've all drifted into an essentially even distribution around the planet. In theory, they could have all been released simultaneously and used their thrusters to navigate to where they needed to be, but this would have increased the risk of collisions, and it would have meant that some of the sats used more fuel (and thus had lower orbital lifespans) than others. This way, they all reach their proper locations at about the same time, each with about the same expenditure of fuel.

Note that while GEO comsats typically need very little station-keeping fuel, they still need an engine to circularize from GTO to GEO, and they also need enough dV to remove themselves into a high graveyard orbit at the end of their lives. In contrast, LEO comsats don't really need to circularize, and they don't need fuel for a terminal graveyard orbit insertion, but they do have a lot more station-keeping needs because of the higher drag in low orbit. 

2 hours ago, Jaff said:

i didn’t think of the expense of the logistics of recovering the booster. It’s costly to recover using drone ship, crane, truck etc. Just to get it back and strip it down because the block 3 isn’t meant to be reused more than once. 

Still doesnt answer why they had fins on it unless they wanted to bin it in a specific place. In which case it makes sense that they used a dirty old interstage with crappy alu fins.

It wasn't a different interstage; it was the same interstage as the one used on the first flight. They don't take the interstage off between flights.

The simplest reason why they'd have fins on it was to guide it down precisely so that there was no risk to the fairing recovery boats/crews. They also probably used the opportunity to do some end-of-life destructive testing for varying entry regimes. They might have tried testing various failure modes, like landing on two engines instead of three and using gimbaling to compensate for thrust asymmetry.

2 hours ago, Jaff said:

id have imagined the engines would be worth recovering no matter what though 

SpaceX is intentionally trying to avoid the Shuttle-style "recover and rebuild" approach to reusability. Elon believes that reuse isn't profitable unless it can be rapid, and recovering old engines to be rebuilt and installed elsewhere doesn't fit. Plus, then you'd end up with a booster that had a mixture of new engines and reused engines, meaning the lifetime of that booster would be tied to those engines rather than all the other brand-new hardware. And you'd potentially have engines with different thrust ratings.

I can see them swapping reused engines in and out in future expendable launches, if a particular engine showed anomalies during the static fire. But they've recovered 20 boosters at this point so that's a stock of 180 engines they could choose from...

[CatastrophicFailure]

4 hours ago, PB666 said:

What about a satellite made of 1" thick titanium designed to survive an explosion and reentry that documents UDE it could have little tiny force wires attached to the payload fairing documenting the forces of take-off, the event, temperature sensors that document the heat, three dimensional accelerometer, a small gyroscope that allows it to orient itself during a fall. Of course it would have to have a very durable battery and a transponder to tell everyone where it landed.

It’s a good bet they’ll be measuring most/all those things anyway, if in slightly more mundane ways. 

3 hours ago, Just Jim said:

Orson Wells would have been so proud... 

 

This remains his greatest UFO ever... and would have been far more terrifying in the sky.