You are not logged in.
bump
Offline
Starship: Elon musk calls world's heaviest rocket too light to reach orbit
"Flight 2 actually almost made it to orbit. In fact, ironically, if it had a payload it would have made it to orbit. Because the reason that it actually didn't quite make it to orbit was we vented the oxygen, and liquid oxygen ultimately led to fire and an explosion. Because we wanted to vent the liquid oxygen because we normally wouldn't have that liquid oxygen if we had payload. So, ironically, if it had a payload it would have reached orbit," Musk said.
So, the ship is going to need to have even more fuel to be able to get all payload to orbit and if the tanks were at capacity that will be a problem.
Musk, however, was still being determined by the loss of hardware and said that he was willing to sacrifice more rockets if it meant that Starship would be operational sooner. "It is always better to sacrifice hardware than sacrifice time. Like, time is the one true currency," he said.
He also outlined the new goals for the third integrated test flight, scheduled for February, pending approval from the Federal Aviation Administration (FAA). These include performing an in-space engine burn from a header tank, a smaller propellant tank that feeds the engines during landing, and safely deorbiting the spacecraft.
Offline
Now we know why Starship's second flight test failed
Elon Musk explained how a fuel venting near the end of the burn was responsible but entirely avoidable next time. lack of a payload meant that it needed to vent some of the liquid oxygen propellant. The booster almost made it to orbit and would have succeeded if it had had a payload.
So knowing cargo mass determines fuel loading with little margin for error
Offline
I think I already addressed this in another thread.
The mistake was venting while the engines were burning. The vehicle is still accelerating, so anything you vent anywhere laterally, effectively moves at the vehicle acceleration rate to the rear of the vehicle, where it can get entrained into the gases between and among the engines in the engine bay.
Had they waited to vent until the engines shut down, laterally vented oxygen would have continued its lateral location and motions, far from the hot stuff in the engine bay.
This is elementary fire triangle stuff. It should have been foreseen.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Starship v3 just grew to stack of 150M making the ship even larger
Offline
image from next big thing page of startships timeline
The 2030 build up for first flights to the 2050 timeframe that is the intense period of man build up from exploration to settlement building.
The future mining to get nanorods to cause heating will require to many launches to achieve the goal.
Like all things with an aggressive time schedule there is bound to be problems with safety of personnel.
Musk's SpaceX sued for negligence in accident that led to worker's coma
Was trying to make posts when 60 plus guests were on the site which seem to be causing delay of page movement and all forms of web activity.
Offline
Offline
NASA hire SpaceX for its Mars trip? I wondered when that might happen! Especially since NASA has been doing none of the things necessary to send humans to Mars. $4B-a-launch SLS's sure as hell aren't the vehicle.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
SpaceX boss Elon Musk predicts date of next Starship test flight expects the third Starship test flight to launch “in about three weeks.”
Elon Musk hints Starship to soon break NASA's human spaceflight record by reaching the moon within five years, pave the way for a private space station, and even pique the interest of the Pentagon for sensitive missions.
Offline
SpaceX announces date of next test flight: March 14
SpaceX: Starship's Third Test Flight
They're continuing to use hot staging. Will open & close the cargo door, and demonstrate propellant transfer. I don't know what they will transfer to. A payload deployed from the cargo bay? Splashdown in the Indian Ocean.
Offline
The key words in the SpaceX press release are "pending regulatory approval". They do still have to satisfy the FAA that they addressed all the shortfall list objectives well enough, from the last one.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
SpaceX's livestream of the launch attempt is set to begin on Thursday at 7:30 a.m. ET, broadcasting on X. However, it will likely start 30 minutes before the intended liftoff time, as SpaceX loads the rocket's boosters with fuel.
https://twitter.com/i/broadcasts/1LyxBnOvzvOxN
If all goes according to plan, Starship will separate from its Super Heavy booster high above Earth and fire its own Raptor engines to enter orbit. The giant spaceship should fly roughly halfway around the planet, then enter a freefall to splash down into the Indian Ocean near Australia.
If that works, it will be a major event in spaceflight history. Starship's heft could revolutionize spaceflight. SpaceX says Starship will be able to carry up to 250 metric tons (275 tons) of stuff to space.
For comparison, the most powerful rocket in operation right now is SpaceX's Falcon Heavy, which carries up to 70 tons.
Offline
Launch license has been granted. Launch scheduled for 7:00am Central Time, coverage starts 6:30am CT.
Offline
Today's launch view is different from previous ones...
Elon is now using X to deliver the video, and when I first connected I got a persistent message that "Something went wrong - Please try again".
Then I wondered if we have to log into X to see the video. I wouldn't be surprised. This is an opportunity to increase the use of X.
I logged in using my Google account, and checked the "Follow" box ... The start time is now given as 8:37 AM Eastern time. and the status is "Following".
It is now 8:26. Not much is happening. There is a Chat button but it is not active.
There is a [Say Something] window but it is grayed out.
update: The X feed reports that fueling is starting but there is a concern about winds. New estimate for launch is 8:29 Central Time.
Update: Thanks to RobertDyck for YouTube tip .... YouTube is working ... I closed the X connection.
Update: Viewer count is estimated at 144K. The feed is breaking up ...
The Chat window is moving fast.
The feed appears to be Everyday Astronaut ...
Update: Cleared the tower .... >> Starship reached orbit.
The booster appears to have performed hot staging and the loop to return properly.
However, only one engine lit is the last kilometer before impact, so I assume it landed in the Gulf.
(th)
Offline
Watching official SpaceX YouTube channel. Was excellent coverage but changes to a recording of Elon pitching crypto.
Offline
X redirects to SpaceX website. But that shows all black when I try to view with my smartphone: Android 10 with the latest Firefox browser for Android. Using my girlfriend's iPad to watch the NASA Spaceflight channel on YouTube. It says targeting for 8:25am CT launch.
Was originally scheduled for 7:00am launch with 110 minute window.
Offline
I just watched the video posted on SpaceX's website.
They did achieve a large amount of success on this test flight. Congrats are certainly due. The ascent looked great, including hot staging and booster turnaround. As near as I could tell, all the on-orbit objectives were accomplished.
The booster apparently was able to execute its boost-back burn just fine. It's not clear to me whether there was an entry burn at all, which the Falcon cores have to execute. Looked like only one engine lit for the landing burn, out of 3 intended. There's a relight issue there, despite the propellant settling effect of the grid fins.
The ship looked pretty good into entry. The video coverage was spectacularly and unbelievably good!
They didn't seem to know they had lost the ship during entry until it should have come out of hypersonics, but still there was no signal. But, I saw way too many tiles coming off as the heating built up and the gees began increasing, while still approaching peak heating!
They should be losing signal just before the peak pulse of heating, due to the intensifying plasma sheath, with the peak deceleration gees several seconds after that. And then shortly afterward the glowing plasma should be all dissipated, allowing signal again.
My guess is that it broke up due to multiple (many?) burn-throughs between peak heating and peak gees, around 55-60 km up, and a speed still in the 7-8 km/s range. The effective plasma temperatures would fall in the 7000-8000 K range at that point. You simply cannot afford burn-throughs. The tiles simply have to stay on it!
And the tiles-coming-loose issue will likely be the very toughest issue (of several) they still have to face and solve.
All in all, a spectacular test! And very informative. Great progress. Just don't forget that there is still a very long way to go.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
I am disappointed. They appear to require re-learning all the lessons of Falcon 9. Why?
Commentator for the channel I watched said Superheavy was supposed to ignite the middle ring of engines for re-entry burn. That never happened. And 3 engines were supposed to ignite for landing burn. Only one did. Result was a hard landing.
Starship rolled a lot after closing the cargo door, before atmospheric entry. That looked like loss of control. And view inside the cargo bay showed light with each roll, implying the cargo door was not fully closed.
Offline
Very impressive. The launch seemed to go perfectly. The booster appeared to be doing 1000kph when it reached 0km, so I guess it broke up on the ocean surface.
I was never quite clear why reentry shields were made from thousands of individual tiles, any one of which is a failure point. It would appear wiser to plaster a fibre reinforced ceramic in layers.
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
Offline
Update from SpaceX. The booster experienced a RUD after the landing relight before contacting the water:
"Super Heavy successfully lit several engines for its first ever landing burn before the vehicle experienced a RUD (that’s SpaceX-speak for “rapid unscheduled disassembly”). The booster’s flight concluded at approximately 462 meters in altitude and just under seven minutes into the mission.“
https://www.spacex.com/launches/mission … p-flight-3
So SpaceX still has not demonstrated the Raptor can relight reliably in flight. In fact, all the Starship landing tests and actual flight tests have shown it is not reliable after relight in flight.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
Offline
Analysis by Scott Manley
YouTube: SpaceX Orbit Largest Spacecraft In History also SpaceX Destroy Largest Spacecraft In History.
Offline
Some miscellaneous observations regarding what I saw in the video SpaceX posted on its website:
1. I saw normal-looking and some abnormal-looking views of the glowing plasma as re-entry began. Bear in mind that the video ended before peak heating, and so well before peak deceleration gee, so the speed throughout the video was nearly orbital: something in the 7-8 km/s range. The most striking abnormal view was a sort of radial "flaring" of orange streamers, looking aft alongside the vehicle. I suggest that for those seconds, that was evidence of flying tail-first directly into the wind. There were some other abnormal-looking views, suggesting improper directions of flow. Remember, it is supposed to enter belly-first at 60-degree angle of attack. Nothing else is survivable. Therefore, I have to ask whether the ship lost attitude control and tumbled, before it broke up.
2. I did see many hexagonal dark objects departing over several seconds of video, which I took to be heat shield tiles coming from forward out of the camera view. That alone would have led to burnt-throughs which would have caused a breakup. That failure mode does not require a loss-of-control tumble, although such will occur during the actual breakup, which would have occurred after loss of signal, because of the plasma being opaque to radio. However in hindsight, I think we actually saw evidence of both tile loss and loss of attitude control, almost but not exactly simultaneously.
3. I have to wonder if one of the forward flaps departed from the vehicle because of tile loss burn-throughs at or near its mounting. Based on the narration, the camera was mounted on one of the forward flaps. As it moved, the camera view moved, in a deceiving manner. You have to allow for that, watching. But such an event (loss of one forward flap leading to end-over-end and rolling tumbling) may well have occurred. It would have been the one the camera was not riding on, and we would not have seen it depart in the camera view, with the vehicle body obstructing that view. Such a loss would have imparted overwhelming pitch and roll disturbances, which I think we saw in the abnormal-looking plasma flow directions.
4. A guess: entry was normal until tiles were lost near the forward flap attachment, on the side opposite the camera, leading to its departure from the airframe, and a complex tumble in both pitch and roll, leading to the abnormal-looking plasma flow directions right before signal was lost. Such caused breakup of the vehicle, only seconds after the signal was lost, and entering peak heating.
4. I would suggest to SpaceX that they fly some entry articles on their Falcon Starlink launches. These would be for a whole lot more testing of ways and means to retain tiles better, between the actual Starship/Superheavy flights. Tile loss really is the long pole in their tent! They can always add thruster forces to aid the flaps for better attitude control during the hypersonics. Shuttle did. It works.
I know there are SpaceX people that read these forums. I hope the recognize likely-good advice when they see it, and not fall prey to "not invented here" thinking.
GW
Last edited by GW Johnson (2024-03-15 10:43:16)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Tile loss is a great concern. I notice they use steel pins to secure tiles. Shuttle used felt glued to the aluminum skin, and tiles glued to the felt. Heat is sufficient to cause tiles to expand more than the aluminum skin so felt was a flexible means of allowing that expansion ithout snapping off tiles. SpaceX uses steel pins with an air gap between stainless steel skin and tiles. But those pins do not appear good enough. Yes, the Shuttle method was a pain in the ass to maintain, but at least tiles stayed in until hit by chunks of ice. Shuttle's worst problem was condensation freezing to ic inside the open cell foam, resulting in a block here the foam acted as reinforcement like rebar within concrete. Starship doesn't have foam so ice is thinner and not reinforced, but debris we saw coming off lead me to suspect ice under the tiles that broke loose during entry.
Offline
After posting I had another thought. In Canada foundations are dug below the frost line; if moist soil under the foundation freezes, expansion as water freezes to ice pushes up the foundation. That never occurres evenly, twisting the house and causing cracks in walls. Could condensation under SpaceX tiles freeze, pushing the tiles and snapping pin attachment?
Offline
Some miscellaneous observations regarding what I saw in the video SpaceX posted on its website:
1. I saw normal-looking and some abnormal-looking views of the glowing plasma as re-entry began. Bear in mind that the video ended before peak heating, and so well before peak deceleration gee, so the speed throughout the video was nearly orbital: something in the 7-8 km/s range. The most striking abnormal view was a sort of radial "flaring" of orange streamers, looking aft alongside the vehicle. I suggest that for those seconds, that was evidence of flying tail-first directly into the wind. There were some other abnormal-looking views, suggesting improper directions of flow. Remember, it is supposed to enter belly-first at 60-degree angle of attack. Nothing else is survivable. Therefore, I have to ask whether the ship lost attitude control and tumbled, before it broke up.
2. I did see many hexagonal dark objects departing over several seconds of video, which I took to be heat shield tiles coming from forward out of the camera view. That alone would have led to burnt-throughs which would have caused a breakup. That failure mode does not require a loss-of-control tumble, although such will occur during the actual breakup, which would have occurred after loss of signal, because of the plasma being opaque to radio. However in hindsight, I think we actually saw evidence of both tile loss and loss of attitude control, almost but not exactly simultaneously.
3. I have to wonder if one of the forward flaps departed from the vehicle because of tile loss burn-throughs at or near its mounting. Based on the narration, the camera was mounted on one of the forward flaps. As it moved, the camera view moved, in a deceiving manner. You have to allow for that, watching. But such an event (loss of one forward flap leading to end-over-end and rolling tumbling) may well have occurred. It would have been the one the camera was not riding on, and we would not have seen it depart in the camera view, with the vehicle body obstructing that view. Such a loss would have imparted overwhelming pitch and roll disturbances, which I think we saw in the abnormal-looking plasma flow directions.
4. A guess: entry was normal until tiles were lost near the forward flap attachment, on the side opposite the camera, leading to its departure from the airframe, and a complex tumble in both pitch and roll, leading to the abnormal-looking plasma flow directions right before signal was lost. Such caused breakup of the vehicle, only seconds after the signal was lost, and entering peak heating.
4. I would suggest to SpaceX that they fly some entry articles on their Falcon Starlink launches. These would be for a whole lot more testing of ways and means to retain tiles better, between the actual Starship/Superheavy flights. Tile loss really is the long pole in their tent! They can always add thruster forces to aid the flaps for better attitude control during the hypersonics. Shuttle did. It works.
I know there are SpaceX people that read these forums. I hope the recognize likely-good advice when they see it, and not fall prey to "not invented here" thinking.
GW
Hi, GW,
So the main issue is about fixing the tails to the fuselage and to the flaps?
Last edited by Quaoar (2024-03-15 15:16:48)
Offline
