ecarfan
Well-Known Member
I think if the solution was that simple, SpaceX would have implemented it. But they did not. They are actual rocket scientists.
snort
Member
They probably do to some degree. An ordinary vacuum pump (e.g. used by an air conditioner repair tech) can pull about 14 psi of vacuum at sea level. call it 95%. I'm sure spacex can do better than that, but maintaining a real, space level, hard vacuum is hard to do and probably not cost effective. But if there's air inside, that fairing is going to try to come off when internal pressure exceeds outside, and they definitely don't want premature release. So my guess is they depressurize it has far as they can to some reasonable cost/benefit point, and then at some sufficiently high altitude, open a port to let out the little air that's left. The port can be pretty small since there's not as much air inside as if they were working from sea level pressure. Simply carrying the vacuum pump and leaving it running might work too.
-Snortybartfast
That’s exactly how fairings work.
To my knowledge there's no such thing as active (de)pressurization. It doesn't make sense from a KISS perspective--you'd just make bigger holes instead. I suspect its actually the fairing separation system that's having the pressurization problem...Vents come in different flavors--check out the repeated features around the circumference of these various fairings. F9's are kind of outties (the blue circles on the roadster photo), Ariane's are kind of oval, Atlas's are circular (its been a while but I think the payload vents are the many circles just above the boattail and the [rocket] avionics vents are the bigger circles on the boattail).
Mike1080i
Member
I'm more familiar with the Shuttle orbiters and that's not the case. Vent doors were used to manage the purge flow on the pad and opened on ascent to equalize pressure in the payload bay on the ride up hill. I would think most launch vehicles with unpressurized payloads do basically the same thing. Here's a link about the Orbiter Purge, Vent and Drain System. But I don't think the purge system is the pressurization system they are looking at, I agree with @bxr140 it might be the pneumatic system used for fairing separation.
The article I saw said that launch time is 16 hours before ULA, but SpaceX is not yet approved (due to ULA being on 41 already).
ggr
Expert in Dunning-Kruger Effect!
That's, like, tonight on the west coast... why is there no mention on spacex.com, no webcast, etc...
Mike1080i
Member
Hmm... Latest positions show Go Pursuit and Go Searcher are in port and Go Quest looks like it's on the way back. Probably resupplying before heading back out, but tonight might be a little too early.
Yes. Looks like it will be pushed out to next week. ULA is forcing the issue. Basically ULA has priority of the range due to SpaceX's delays. ULA is not confirming enough to allow SpaceX to set their time. So SpaceX is forced to push theirs out past ULA's full launch window.
Nikxice
Active Member
I think ULA had a lock on the March 1st launch date. SpaceX likely didn't seriously consider trying for an after midnight launch on March 2nd. The Atlas 5 that launched this afternoon from SLC-41 is only a couple of miles away from SLC-40. Although unlikely, there is always the possibility of collateral damage from an Atlas explosion. To use the common refrain "out of an abundance of caution", today the Falcon 9 was probably safely tucked away in the hangar.
Mike1080i
Member
It maybe expendable, but it is a new booster with legs and grid fins, possibly titanium. They may be planning to try another high energy recovery test while keeping expectations low. With grid fins and legs, might as well try and see what happens!
This was originally thought to be an expendable launch. SpaceX must have learned enough from their recent water landing experiments that they are confident to give it a try.
The tell for this is that they would put titanium grid fins on. If they're aluminum then they will consider the fins expendable.
ecarfan
Well-Known Member
Seems unlikely that SpaceX would install titanium grid fins on a core that was going to be expended.
favo
P3D+ owner
Weather is 90% go for tonight. If it slips then tomorrow is only 70%.
The webcast might be up by now.
Great article with details on this launch. It seems this author is willing to count the Amos 6 anomaly rocket as a launch.
The Falcon 9 rocket may reach 50 launches on Tuesday – Ars Technica
The webcast might be up by now.
Great article with details on this launch. It seems this author is willing to count the Amos 6 anomaly rocket as a launch.
The Falcon 9 rocket may reach 50 launches on Tuesday – Ars Technica
