Which ablative surfaces?
I guess the intent is that nothing ablates except water.
If there were anything else ablating, I expect it would be surfaces of the launch mount or the flame deflection system that get exposed to flame blast without adequate water protection. But I would assume that would be “nothing” unless we begin to see evidence of surface erosion after a hot-fire test or a launch.
If the rockets are meant (Eventually) to launch multiple times, not much is abating from the rocket engines themselves. The idea of the wate deluge is to prevent the flames from having significant effects on anything else.
There is one thing that ablates (or has ablated) on launch: the paint on the stand. Maybe some cleaning residue or lubricant left on launch mount parts would join the water, but it would be miniscule amounts.
The only thing I can think of that could have an environmental effect is the rapid runoff of the water, if it’s draining into the ocean. But fresh water runoff happens after every rain, so…
I personally doubt F&WS will find anything of note, but evidently it’s a mandatory box to check in the process.
It’s not the findings SpaceX particularly has to worry about. It’s the schedule.
All of them? Any surface of the launch mount hit by the exhaust of a raptor engine in close proximity will begin to vaporize. I doubt they are using exotic materials that would be immune to that.
That seems unlikely. SpaceX is discharging a large amount of fresh water into a protected area. Such discharges are not natural and will certainly have environmental effects. While imagine one could hope that the Fish and Wildlife service would just guess that it won’t be that bad, a prudent person would not make such an assumption. Filing an environmental study 135 days ago would have been a reasonable precaution to take. Even if the study would have had to cover several possibilities.
By not natural I mean the water will come from a small source and flow quickly through drain patterns that don’t exist naturally. Certainly a heavy rain introduces a lot of water, but not in the same pattern as an industrial discharge.
And now we have a looming government shutdown almost certainly forcing a day-for-day slip of that deadline.
A nice X/Twitter thread on the pad failure:
I got word today that our research into the Starship launch pad anomaly is being forwarded uphill to NASA HQ. They are focusing on what we learned about launch/landing pad failure modes and how we can make lunar landings safer. /1
2/ What we found is that the pressure that built up beneath the launch pad was comparable to a volcanic eruption when the buildup of hot gas that evolves from the magma busts apart the caprock and expels it. (Pic: Fagents & Wilson, Geophys J Int 113(2): 359.)
3/ The theory on these volcanic eruptions predicts a range of velocities that matches what was measured for the ejected chunks of concrete from the Starship launch pad — about 90 m/s.
4/ But to explain the mass of gas needed to expel at this velocity, we had to conclude that groundwater under the pad was vaporizing. We estimated the water based on crater volume and permeability of the sand under the pad. It is in the range that agrees with theory.
5/ This raises the question about ice in lunar polar soil under a launch pad. If the pad cracks and hot gas is pushed through (like we think happened for Starship) then vaporization of the ice may create a similar situation. Ice can be as much as 5%wt (actually higher), which…
6/…predicts that ejection velocity of a lunar launch pad could be even faster than what happened for Starship. 5 wt % vs 1 wt % on this plot.
7/ So we need to develop methods to prevent this. It shouldn’t be hard to do. Examples: make the pad thicker. Measure the ice before construction. Put vents under the pad. In fact…
8/…we are already collaborating with Cislune on a project to develop these technologies. “Deflector cone and vented launch pad” — read more here:
9/9 So that’s how the Starship launch pad anomaly, while not desired ofc, turned out to produce insights for engineering lunar landing technology. This is the message that got attention and is being sent up to NASA HQ.
That it took one of the top experts on rocket/soil interaction several months to work out what happened, which included insights that apparently hadn’t been considered before, suggests that the earlier attempt wasn’t quite as dumb as some have made it out to be.
It really was a novel failure mode, and the knowledge gained may prove crucial for future lunar missions. Hopefully the full paper shows up on the NASA servers soon.
Interesting. It’s an ill wind indeed that blows no good. Provided of course you look hard enough to find that good. As these folks did.
Aside
Thank you for quoting the relevant parts of that. Lotta Dopers just post links to X/twitter that some of have completely blocked. The sooner all decent people block that company, the sooner it dies. But that’s politics, not rocket science. Hence the hiding.
Lesson: soil hydrology matters. Especially if your high temperature launch surface is just above the water table less within rock-throwing distance of the sea.
was this never an issue with Cape Canaveral? Or is that subsurface bone dry? Or was it the lack of flame deflection mechanisms in Texas?
NASA always built ginormous flame trenches at Cape Canaveral. Those took the rocket exhaust and redirected it sideways.
Basically an enormous below-ground concrete trench, and a water-cooled thrust redirection plate.
But as they say: any idiot can build a bridge that stands. It takes an engineer to build a bridge that just barely stands.
In other words, was the flame trench overkill? NASA isn’t known for cost optimization, but for SpaceX it’s a core part of their strategy.
And it looks like a full trench is overkill, while a plain concrete pad is insufficient. So they have an intermediate approach of a flat pad–no trench or redirector–but with a large amount of water cooling.
SpaceX could have spent $1B or whatever to have something guaranteed to work, and which probably would have added another year or two of construction and approval time. Not their style, though.
SpaceX is not happy about how fast the FAA moves:
Mainly, they’re complaining about the FAA being understaffed:
During the hearing on Wednesday, Gerstenmaier will recommend that the FAA double the staff in the licensing division of its Office of Commercial Space Transportation, which is known as AST. In addition, the FAA should be given “accelerated hiring authority” to draw from the best pool of candidates.
The company also believes that license applicants should be able to opt-in to help fund independent third-party technical support to assist the FAA surge in the near term while the agency goes through the hiring process.
Doesn’t seem unreasonable. Of course, there’s always the problem that third parties hired by the original company might have an incentive to overlook some issues, but I don’t think that’s impossible to overcome. AFAIK, drug companies do the same with the FDA.
They cite some examples of where they are holding back on their own projects because they’re competing with themselves for FAA resources. And it will only get worse with the new rocket projects on the horizon.
Also, it seems that November (or later) is likely now:
As the consultation with FAA and US Fish and Wildlife over the Starship mishap will likely push into November, further delaying a second launch attempt, SpaceX is calling on Congress to push FAA to issue launch licenses faster - The Washington Post
This problem is all over FAA. The industry is growing and FAA isn’t. Congress won’t allocate more budget even when they’re being fully functional. Which as we know they are not being recently, as in last 5-10 years.
There’s also a very loud drumbeat of retirements. They really need the newbies in for a few years to learn before all the expertise retires. But that ain’t happening either.
Then you add what occurred with certification of the MAX, where at least arguably the Boeing employees deputized to act as FAA regulatory reps were somewhere between asleep at the switch and actively suborned by Boeing management. In response to that, or at least the perception of that, Congress mandated that vast amounts of work be moved from the applicants back into the agency. Yet provided zero allowance for more headcount to do that newly mandated work. And also made it clear the FAA needed to require far more stringent analyses of everything, and redo those analyses for themselves rather than taking the applicant’s engineers’ word for it. Vastly increasing the FAA workload again with no additional man-hours to do that work either.
The net result is approvals that used to take a month of FAA work now take 6 months of FAA work. And are waay back in a queue of other delayed and slow-moving work whose back end is moving out at the horrendous rate.
Whatever SpaceX wants, getting the right to do their own approvals is almost certainly not on the cards. neither is getting anything approved quickly.
The alternative to Congress spending more money is regulators being paid for by user fees–and it sounded like SpaceX might be receptive to that.
Quite right. But Congress would have to write the laws allowing this change. Them the FAA or OPM would have to write the regs. then the industry lobbyists would get involved. It’d be 5 yeas before the first fee was collected or the first worker hired.
As I’ve said, D D Harriman would not have put up with this shit. He’d have built a launch site outside the FAA jurisdiction and damn the torpedos. Exporting technology? Hell no, all our engineers are from the local country. The engineering and physics are all public domain.
This is understandable given the Boeing situation, but there is such a thing as too much in-housing. The article gives this example:
For example, when SpaceX sought to move its tank farm at Launch Complex 39A in Florida, it submitted paperwork and received approval from both the US Space Force and NASA’s Kennedy Space Center. The company was not seeking to move the fueling operations outside the fence line, but rather just to reposition them inside.
However, it also had to get approval from the FAA, and this, again, diverted resources away from reviewing Starship activity. Was this the best use of FAA resources when the Space Force and NASA had already signed off on the plans?
The FAA doesn’t have to trust the applicant’s word here–but they could have trusted NASA and the Space Force, especially for ground infrastructure within the fence line. It seems like needless redundancy.
Everybody at FAA is running scared. That doesn’t help.
Nobody wants to to be the middle manager or the senior executive who has the next “If you’d have looked harder at [whatever] this wouldn’t have happened” scandal occur under their charge.