from the I-get-knocked-down-but-I-get-up-again dept.
NASA and SpaceX stand down on Dragon launch to study hydrazine issue:
NASA and SpaceX have delayed the launch of a Cargo Dragon spacecraft for at least a couple of weeks due to an issue during the prelaunch loading of hypergolic propellants.
The space agency had been planning to launch the spacecraft on June 12 but announced the delay in an email on Monday evening to reporters.
"During propellant loading of the Cargo Dragon spacecraft, elevated vapor readings of mono-methyl hydrazine were measured in an isolated region of the Draco thruster propulsion system," the space agency's statement said. "The propellant and oxidizer have been offloaded from that region to support further inspections and testing."
Draco thrusters provide on-orbit maneuvering propulsion for the Dragon spacecraft. NASA said that it is working with SpaceX to identify the source of the elevated readings and take any corrective actions. On Tuesday morning, astronauts on board the International Space Station were told by Mission Control in Houston that the launch date would slip until at least June 28.
This is not a new Dragon vehicle. Designated Dragon "C208," this vehicle has previously flown two supply missions, both in 2021. It is an upgraded version of the original Cargo Dragon spacecraft, known as "Cargo Dragon 2."
See also: Dragon Mission on Hold as Astronauts Conduct Eye Exams, Spacesuit Work
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A SpaceX cargo mission to the International Space Station has been pushed back to no earlier than July 11 after teams discovered elevated vapor levels of propellant. [...]
Following additional inspections and testing of the Dragon spacecraft, the investigators managed to identify the source of the leak as being a faulty Draco thruster valve inlet joint, which controls the flow of propellant. [...]
This marks the second delay for the cargo resupply mission, the first delay being announced on June 6. The first delay happened after ground teams detected elevated vapor readings of mono-methyl hydrazine while loading the propellant, forcing them to stand down from the launch attempt. [...]
The NASA and SpaceX partnership continues to be a strong one. The space agency recently bought five additional Crew Dragon flights to the ISS after NASA's other commercial partner, Boeing, failed to deliver its own crew vehicle on schedule. The recent glitch with Crew Dragon, it's fair to say, likely won't have much of a bearing on this fruitful working relationship.
Previously: NASA and SpaceX Stand Down on Dragon Launch to Study Hydrazine Issue
(Score: 2) by PiMuNu on Thursday June 09 2022, @11:18AM
more bugs mean more fixes...
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @11:26AM (1 child)
Seems unlikely, but does the Cape have a common hydrazine supply?
If so, all this on and off loading, could move contaminates between vehicles.
(Score: 2) by ElizabethGreene on Thursday June 09 2022, @03:45PM
(I am not an expert.) My understanding is that this would indicate a leak, not contamination.
My opinion doesn't matter a unicorn fart, but a hold seems appropriate. Hydrazine is both an explosion and toxicity hazard and the last failure in the SuperDracos caused a loss of vehicle in a pad test*.
*4/20/2019 That turned out not to be related to MMHZ. They discovered a previously unknown chemical reaction between Nitrogen Tetroxide and Titanium in a valve at high pressure.
(Score: -1, Offtopic) by Anonymous Coward on Thursday June 09 2022, @11:57AM (4 children)
Had to look that up.
The "go" in the word is from Greek, to work.
In this sense of the word it is an adjective to describe fuel that does not need ignition and reacts, (works on its own).
Now if AC could have hypergolic Moderation, that could be helpful in reducing the Troll or Flamebait mods for all the little piss ants on here that actually just Disagree.
(Score: 5, Informative) by ElizabethGreene on Thursday June 09 2022, @03:51PM (2 children)
Correct. Hypergolic means it burns without requiring a separate ignition source. That's good because it eliminates a whole bunch of fiddly bits required for spark or glow ignition. It's bad because it will ignite whenever the two compounds mix. Ideally that happens in the combustion chamber, but it can be super bad (aka "Rapid unscheduled disassembly" bad) if it happens in e.g. a valve, supply line, or in a tank because of a leak.
Another Hypergolic mixture is TEA (“triethylaluminum”) + TEB (“triethylboron”). This is what SpaceX uses as an ignition source to light (and relight) (usually) the engines on the Falcon 9 boosters. The first Falcon heavy center core was lost when it ran out of TEA/TEB and couldn't relight for its landing burn. That was a bummer. :/
(Score: 4, Informative) by Spamalope on Thursday June 09 2022, @04:06PM (1 child)
Yep. This indicates a leak, which is super duper bad for a hypergolic fuel.
You don't want that for the vehicle, and really don't want it once it reaches the station.
This is a 'must be 100% found and solved' problem.
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @06:20PM
On the up-side it shouldn't be too difficult to find the source. One of the advantages of designing for easy maintenance.
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @06:46PM
Can someone please explain the Offtopic Mod?
Cause I'm having trouble seeing how this is not what we are talking about here.
Christ, even the comments replied to it, are those not offtopic too then?
(Score: 3, Insightful) by DannyB on Thursday June 09 2022, @04:18PM
But SpaceX makes it look easy.
To transfer files: right-click on file, pick Copy. Unplug mouse, plug mouse into other computer. Right-click, paste.
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @06:51PM (3 children)
"The propellant and oxidizer have been offloaded from that region to support further inspections and testing."
One would think offloading the entire combustables payload is more prudent.
How do the sequester a "region" anyway?
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @07:26PM (2 children)
It all depends on how the valves are laid out. From the sound of it there is a leak in a thruster pack so they sealed it off and drained it for analysis. They don't suspect a problem with the main tanks or the other thruster packs so it's safer to leave them alone.
(Score: 0) by Anonymous Coward on Friday June 10 2022, @01:05PM (1 child)
not sure why no mod points for your excellent comment...ah...but this is Soylent, so to be expected as they scare the user base into hiding behind AC.
Sad.
(Score: 0) by Anonymous Coward on Friday June 10 2022, @05:56PM
Hiding behind AC as opposed to hiding behind anonymous named account? What's the difference?