What's up with the techs getting right up to the Dragon capsule?

August 2, 2020 4:28 PM

I noticed, skimming through the Dragon splashdown today, that the techs on the boat seemed to just walk up and start working on the capsule right after they plucked it from the briny deep. That seems weird. What's up with that?

On google it uses the same horrible hypergolics as the shuttle orbiters did, so I would have thought it was another "In the name of all that is holy stay FAR AWAY until that shit is safed" situation. So:

(1) Did I just miss them safing the systems because I was admittedly scrubbing through and asking y'all is more interesting than watching several minutes of low-bitrate video?
(2) Or is their tech legit better-enough than the orbiter tech that they could reasonably be confident that they won't die in nasty dimethylhydrazine ways?
(3) Or is this is another instance of Elon "LIFE IS CHEAP" Musk?
(4) Or, least likely, has their been some kind of re-evaluation of the precautions you need around hypergolics?

posted by GCU Sweet and Full of Grace to Travel & Transportation (6 answers total)

Best answer: I remember it! At around 4:48 in the YouTube video, they mention that the fast boats were waiting for permission to go in and begin the hypergolic sniffs.
posted by kimberussell at 4:50 PM on August 2, 2020

Response by poster: Thanks for saving me from the eternal heartbreak of... watching it again!
posted by GCU Sweet and Full of Grace at 4:58 PM on August 2, 2020 [1 favorite]

Response by poster: (erm... that's sincere; I just recognize that there was a lot of "I don't wanna spend a minute doing this myself" to the question)
posted by GCU Sweet and Full of Grace at 4:59 PM on August 2, 2020

There was a second incident beyond the one linked above. After the Dragon capsule was lifted aboard the recovery ship, they had readings above acceptable exposure limits at about 5:21:55. The webcast initially misreports which chemicals were being recorded but clarifies it later on.

As described by the Washington Post:

Technicians aboard the Go Navigator also briefly delayed opening the hatch because of a build-up of harmful fumes around the capsule. Mission controllers detected higher-than-appropriate amounts of “hypergolic fumes,” or fumes that could explode when coming in contact with one another. Tests found no toxic fumes inside the capsule.

posted by JackBurden at 5:39 PM on August 2, 2020

So, I don't know exactly what "safing" they did, but at at 4:44:10 in this video, at an altitude of around 600 meters, the commentator says that "so at this point dragon has safed all propulsion systems on board."

Then later on the fast recovery boats wait for a go ahead to approach the capsule in the water to sniff for hypergolic fumes.
posted by Salvor Hardin at 5:45 PM on August 2, 2020

Yeah, the first boat did a general air-safety check before allowing the other boat to come around and attach the lifting harness. Then once on board when they went to open the door... after removing a little hatch an alarm went off with some levels of the bad stuff at about 2x acceptable limits. They then spent the next 30 minutes or so purging the service-section of the craft (the part that's not the pressurized cabin) to get the levels down to safe. About halfway through they had the crew inside break out some test devices and check the interior cabin and found it clean. The telemetry from the capsule showed no leaks or loss of pressure sort of thing from those nasty rockets. They even asked the crew if they wanted/needed to come out anyway or were content to sit around for another fifteen minutes or so while they did some more purging of the service-section. They finished purging, tested below hazardous and the proceeded with opening the door. They may have just even been over cautious over trace amounts of fumes.
posted by zengargoyle at 6:49 AM on August 3, 2020 [2 favorites]