-
#980
by
meekGee
on 16 Apr, 2023 14:42
-
Have the Karmens stopped fighting about orbital/suborbital?
Joking aside, there was some informative bits in the midst of it.
Good morning!
And, no.
21 hours to go.
-
#981
by
PM3
on 16 Apr, 2023 15:02
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
-
#982
by
rsdavis9
on 16 Apr, 2023 15:09
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Might they try an in orbit engine restart to test this?
-
#983
by
DanClemmensen
on 16 Apr, 2023 15:15
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working. The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.
-
#984
by
joek
on 16 Apr, 2023 15:16
-
Have the Karmens stopped fighting about orbital/suborbital?
...
They're still debating based on focus group feedback from recent appearances, and of course their personal opinions...
An orbital launch is like totally slaying the runway. When a rocket reaches orbit, it's going super fast, cruising around Earth without falling back. It's like rocking an outfit that's meant to keep all eyes on you, making a major statement.
On the flip side, a suborbital launch is like a quick flex. The rocket goes up into space but doesn't have enough speed to stay in orbit, so it comes back down to Earth after a hot minute. It's like wearing an outfit that's just meant for a brief strut on the runway, showing off your style and then dipping out.
So, basically, an orbital launch keeps the rocket orbiting Earth like a total boss, while a suborbital launch sends the rocket into space for a brief moment before it comes back down. Just like the vibes on the runway, the main difference is how long they're meant to stay in the limelight.
YMMV
-
#985
by
joek
on 16 Apr, 2023 15:21
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working. The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.
Worst case is much worse than that, which is why they may have deferred on any entry-landing gymnastics. Potentially a *lot* more review and approvals.
-
#986
by
meekGee
on 16 Apr, 2023 15:23
-
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
Why not just say "orbital velocity on a suborbital trajectory".
The European Space Agency had a (failed) launch some years back that in fact had orbital energy, but alas not quite the right trajectory, hence a crash. In what I think was a brilliant (and accurate) attempt at face saving, they said the craft had entered an Earth Intersecting Orbit (EIO) :-) I nominate 'Earth Intersecting Orbit' as our descriptor for the upcoming flight.
I vote for this.
-
#987
by
Herb Schaltegger
on 16 Apr, 2023 15:35
-
ICBMs dont fly more than half around the globe.
They do if you don't want the target to see them coming. For example a Eurasian nation that wants to hit something in North America could launch due south, over the South Pole, and the ICBM would approach the target from the south, a direction that is not being monitored for ICBMs.
Just correcting the misstatement. Back to the topic now.
Fractional Orbit Bombardment. IIRC, the Soviets were afraid the Shuttle was a first strike FOBS [size=78%]disguised as a white project, now the US is worried about China using hypersonic glide weapons doing the same thing.[/size]
Is China gliding toward a FOBS capability?
https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability
Please take this geopolitical stuff to the Policy Forum, not this thread. It's messy enough with all the pissing at each other regarding the definitions of "orbital" and "suborbital."
-
#988
by
robot_enthusiast
on 16 Apr, 2023 15:37
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
The Written Reevaluation to the PEA that was released alongside the license makes it clear that a significant amount of thought went into minimizing the environmental impact at the splashdown zone. Ensuring a full breakup of the vehicle and minimizing propellant load at the time of impact are both important for that. As soon as they have SECO they will be venting the tanks to ensure the propellant has time to fully boil off.
-
#989
by
alugobi
on 16 Apr, 2023 16:03
-
You orbit kung fu-ers, get a room. Nobody cares what you call it. The flight plan is what it is. stfu
-
#990
by
getitdoneinspace
on 16 Apr, 2023 16:10
-
I'm an avid NSF content consumer. But I don't think any other content provider will deliver what Ellie delivered in this video; an interview with the Brownsville mayor involved in the entire journey of SpaceX in Boca Chica. And the mayor has a heartfelt recognition of what Starship means to her community and to the world (and to her son :-) Very much worth a view.
-
#991
by
woods170
on 16 Apr, 2023 16:29
-
And there it is. Wonder if it was the elevator. Launch ain't happening this week. 
Best to cancel the whole program, butter fingers company obviously not going to hunt.
No but they will have to do a bunch of inspections to make sure nothing propellant, electrical, or hydraulic related was damaged. Kind of important, no? 
Already done.
The incident looked a lot more spectacular than it was because: night.
The incident also sounded a lot more spectacular than it was because: night (less activity, less background noise)
OHSA is not involved because: No people were harmed.
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
-
#992
by
Alberto-Girardi
on 16 Apr, 2023 17:00
-
And there it is. Wonder if it was the elevator. Launch ain't happening this week.
Best to cancel the whole program, butter fingers company obviously not going to hunt.
No but they will have to do a bunch of inspections to make sure nothing propellant, electrical, or hydraulic related was damaged. Kind of important, no?
Already done.
The incident looked a lot more spectacular than it was because: night.
The incident also sounded a lot more spectacular than it was because: night (less activity, less background noise)
OHSA is not involved because: No people were harmed.
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
Good to hear that, still it was pretty clear that everything was ok since they stacked.
Still it seems that the failure disbled in some way the elevator, since it doesn't seem to have been used.
https://twitter.com/VickiCocks15/status/1647377008077201410
-
#993
by
ZachS09
on 16 Apr, 2023 17:35
-
What time tomorrow morning will the official NSF webcast for the Starship IFT begin?
-
#994
by
alastairmayer
on 16 Apr, 2023 17:39
-
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working.The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.
(emphasis added)
You also need to rewrite the flip-and-land software to account for all the changes since SN15, which are considerable both in hardware and mission profile. All for a one-time attempt (because future hardware and mission profiles will be different again) that S24 may not even survive to try. SpaceX (wisely, IMHO) decided it wasn't worth the trouble.
-
#995
by
meekGee
on 16 Apr, 2023 18:04
-
ICBMs dont fly more than half around the globe.
They do if you don't want the target to see them coming. For example a Eurasian nation that wants to hit something in North America could launch due south, over the South Pole, and the ICBM would approach the target from the south, a direction that is not being monitored for ICBMs.
Just correcting the misstatement. Back to the topic now.
Fractional Orbit Bombardment. IIRC, the Soviets were afraid the Shuttle was a first strike FOBS [size=78%]disguised as a white project, now the US is worried about China using hypersonic glide weapons doing the same thing.[/size]
Is China gliding toward a FOBS capability?
https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability
Please take this geopolitical stuff to the Policy Forum, not this thread. It's messy enough with all the pissing at each other regarding the definitions of "orbital" and "suborbital."
Lighten up.. he was just offering another term (Fractional Orbit) and giving a tiny but of (otherwise) interesting context.
I still vote for EIO though. Exactly descriptive.
Oh and this subtopic won't die until they start fueling the beast...
(Which is when?)
I'm Pacific Time and will have a launch viewing party over an early breakfast
-
#996
by
oiorionsbelt
on 16 Apr, 2023 18:17
-
Looking at the SpaceX test flight timeline.
Anyone know why the ships fuel/methane load starts before the LOX load?
The boosters LOX loading and methane loading start at the same time.
-
#997
by
meekGee
on 16 Apr, 2023 18:38
-
Looking at the SpaceX test flight timeline.
Anyone know why the ships fuel/methane load starts before the LOX load?
The boosters LOX loading and methane loading start at the same time.
Just went to the SpaceX website to look at the timing. (Fueling is about 1 hour, if you want to watch the excitement build)
Why is the flight diagram so god awful?
Booster flies back, and only then performs the flip and then boost-back burn?
Then it flies back, changes its mind, flies forward again (so why not just fly forward to begin with?)
What's happening?
-
#998
by
jimvela
on 16 Apr, 2023 18:52
-
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
I've amplified the noise by believing an early and it turns out very unreliable source that it was elevator-related.
Apologies.
I'm still somewhat amazed that something can fall into or at least down the elevator shaft without grinding work to a halt, and am incredulous about the processing with man lifts and stair access.
There's a lot about this processing flow and the determination and pressure to proceed that makes an old dog like me see it as reckless.
I'll be watching the remaining processing and launch attempt with interest and an open mind.
I do hope that the launch attempt succeeds wildly, and if nothing else I hope that it clears the pad and at least gets down range far enough that the next attempt can be relatively quickly.
-
#999
by
sdfasdfasd
on 16 Apr, 2023 18:57
-
re. The timing.
spacex.com states that the broadcast will begin at 6:15am for a 6:15 + "45 minutes before" = 7am launch, which squares with the 7am "test window" text.
spacex.com also states that there is a Propellant Load Go poll at T-2:00
So we should start looking for the results of that poll at 5am ?
spacex.com also states that the test window will be open until 7:00 + 150 minutes = 9:30am.
So the Starship splashdown will occur at 7am + 1:30 = 8:30am at the earliest and 9:30am + 1:30 = 11am at the latest ?
All times CDT.
