Can they be re-purposed as PPE’s for health care workers in these desperate times?
The other two suits in the photo above show ports on the torso. I don’t see how the thigh is any less (or more) accessible than those locations. They’re all easily within range of both of the astronaut’s arms. Supposedly, the SpaceX suit has some kind of unified connector that combines all the life support functions into one port. That seems ideal from a disconnection perspective.
The panel is just for show. When the astronauts are in the capsule, they’ll already be hooked in. There’s never going to be a point where they’re scrambling to remove the cover in an emergency. They’ll press a button or pull a lever on the connector and it will pop off.
I agree that the oversight leaves much to be desired. However, It’s also clear that Boeing and SpaceX have been held to different standards. Boeing was not obligated to perform an in-flight abort, and they still seem to be trying to wriggle out of their failure to even perform a full demo flight. From the beginning, Boeing’s position has been that they are the safe option due to their long flight history. As it turned out, despite SpaceX being cheaper and having performed more rigorous tests, they’ve also been more successful. Their demo flight was virtually flawless, as was their in-flight abort test.
So while I’d certainly like to know a bit more about the details of their suit, I’m also willing to give them a bit of benefit of the doubt, especially because of their obvious success in the rest of their program. None of the pictured suits show “bellows” at the joints; while some kind of volume-compensating system is needed, whatever the mechanism is, it can be covered with loose fabric. The SpaceX suits do show pleating at the knees and elbows, clearly intended to allow bending at those points.
Flight suits don’t require the same degree of movement as EVA suits. The astronauts need to survive depressurization, allow some freedom of movement in a vacuum, and a larger degree of movement in an atmosphere (like trying to exit the capsule). I see nothing in the SpaceX design that prevents these things.
The Apollo/Skylab A7L spacesuit also had just a single rubber zipper seal between the pressurized interior and vacuum (there was a second, outer zipper for mechanical restraint). It seemed to work well enough, even for EVA purposes. They worked at 3.7 psi, which is sufficient in oxygen. I don’t know what the SpaceX suits are rated at.
In fact, you can see this in the video linked above. There’s a black and silver box attached to the thigh with a tether coming out of it–presumably with oxygen, coolant, and maybe power. There’s a button on the side of the box to disconnect it, which one of the techs does in a second or two without looking at it closely.
Boeing a safe option? Except for all the people who died on the 737Max . Maybe someday that plane will fly again.
video of Russian guy putting on a spacesuit
The ports are on the torso on the ACES and other suits because it is generally someone other than the wearer who connects the port. With the suit on you have essentially no tactile sense and can’t look down so someone else has to attached hoses and confirm that they are secure. Putting ports on the thigh means that whomever is attaching the hose has to go down in “blowjob position” to hook them up instead of doing this in a normal standing position. I hope to the gods that the attachment system doesn’t work the way you describe (“…press a button or pull a lever on the connector and it will pop off,”) because that would be a highly unsafe design for a connection that is literally a life-and-death single point of failure. Current systems use a positive locking ring to assure that the connector is properly seated and secured so that accidentally disconnecting the life support system does not occur.
The A7L had a set of overlapping and interlocking seals that used the positive pressure in the suit to compress and activate the seal, while gantlets were attached with locking ring seals to prevent any sort of leakage through flexure. From the video I can’t really see how the seal on the SpaceX suit is constructed but it doesn’t appear to be thick enough to have much sealing surface, and the location of the openings, going across the wrist, is essentially the worst possible place for the seal to be under flexure next to just putting them on the elbows or knees.
This appears to be a “Rule of Cool” pressure suit design, which works great in movies where space is simulated by a green screen and CGI, and dumber than a concrete balloon in real life.
Stranger
I would think that NASA would use NASA suits, even if someone else made the spacecraft.
The suits go with the ship, they are’t interchangeable. If you’re in Boeing’s ship you’re in a Boeing suit, if you’re in SpaceX ship you’re in SpaceX suit.
Also, the SpaceX suits are custom made/tailored per astronaut to fit better.
I didn’t say there wouldn’t be some system for preventing accidental disconnection. Many critical systems are “just a button”, but hidden by a panel or with an interlock of some kind. Whatever the case, it needs to be quick, able to be accomplished in a degraded environment, and unlikely to happen by accident. Buttons and levers can be designed to meet these goals.
The Launch Entry Suit also used zippered-on gloves. NASA considers the ACES wrist design to be superior but this appears to be more for ease of donning and increased range of movement. Notably, the ABORT MODE control on the Shuttle was a knob, which presumably requires a decent range of wrist mobility. Crew Dragon doesn’t have that problem.
The zipper design is different on the SpaceX suits than the LES, but maybe the entire wrist/forearm area is designed to become rigid under pressure and avoid the flexure problem. The Crew Dragon controls are entirely button/touchscreen based, AFAIK, and wouldn’t need the same level of mobility.
Without any technical details being available, it’s hard to say if they sacrificed function in favor of form. But SpaceX’s track record so far is pretty darn good, so it seems reasonable to give them some benefit of the doubt and wait until we get some details and data from actual usage.
That was a ground test. It’s expected that tests will go wrong from time to time. This particular one uncovered an unusual interaction between titanium and nitrogen tetroxide. SpaceX redesigned their valve system after this failure, switching from check valves to burst disks to eliminate any chance at backflow. SpaceX also had some parachute failures (which uncovered an interesting deficiency in NASA parachute models), and they redesigned that system as well.
It’s less forgivable when a *demo *goes wrong. They are supposed to demonstrate that what should be the final product is actually working as intended. Although for some reason Boeing called their demo flight the “Orbital Flight Test”, these flights are supposed to show the complete operational system. The SpaceX flight was entirely successful; the Boeing flight did not even reach the space station.
Yeah, nobody would ever expect titanium to react and combust in the presence of a strong oxidizer. Except anyone educated in materials science as related to liquid propellant systems.
Recall that SpaceX’s first catastrophic failure was due to the selection of a fastener prone to stress corrosion cracking, using a material explicitly recommended against in MSFC-STD-309 “GUIDELINES FOR THE SELECTION OF METALLIC MATERIALS FOR STRESS CORROSION CRACKING RESISTANCE IN SODIUM CHLORIDE ENVIRONMENTS MATERIALS, PROCESSES, AND MANUFACTURING DEPARTMENT METALLIC MATERIALS AND PROCESSES GROUP”.
Tell me again how “SpaceX’s track record so far is pretty darn good,” such that we should not question whether they are making good design decisions?
Stranger
I don’t recall this particular interaction being mentioned in Ignition!. This isn’t just some general-purpose bad interaction between titanium and a strong oxidizers; it’s the fact that it becomes downright explosive under the right high velocity impact conditions.
I did run across a reference from the 60s that noted the interaction, but unfortunately I can’t find it right now. And as I recall, the result was not nearly as catastrophic as what happened in the SpaceX test. I did find this NASA Technical Note from 1963 (testing oxidizer/metal reactions under which velocity impacts), which could not reproduce any interaction between titanium and NTO–from the summary: “No chemical reaction between titanium specimens and unsymmetrical dimethylhydrazine or nitrogen tetroxide was obtained”. Liquid oxygen was a very different story.
I’m not sure if SpaceX has moved away from titanium components–but they have moved away from a design that allows the helium pressurant and feedlines to act as a light-gas gun firing frozen slugs of NTO into valve assemblies.
Musk himself admits that they were idiots in the early days. They could not find experienced rocket designers, basically because the good ones aren’t going to work for some ridiculous startup. One might think they’ve learned something in the past 14 years.
Still not quite the reference I was looking for, but:
LIQUID ROCKET METAL TANKS AND TANK COMPONENTS
(page 39) The susceptibility of titanium to potentially catastrophic ignition under conditions of impact or other instances of localized high-energy pulses in the presence of strong oxidizers now is widely known. This phenomenon was first observed in red fuming nitric acid (RFNA) and liquid oxygen (LOX). Reactions also have been observed in liquid lluorine and in mixtures of liquid fluorine and liquid oxygen (FLOX), and in pure gaseous oxygen at pressures on tile order of four atnlospheres and greater. Nitrogen tetroxide (N2O4) has also shown a tendency toward such ignition reactions with titanium, but such reactions have been nonpropagating in nature.
The NTO/titanium interaction that caused the Crew Dragon explosion was certainly not “nonpropagating in nature”. Under the circumstances, some degree of ignition might be expected, but what happened went well beyond that.
FLOX? I shudder to think. Go full on crazy and break out FOOF. Even concrete burns.
Or ClF[sub]3[/sub]. It’s hypergolic with asbestos.
So you think SpaceX has not been successful?
Successful doesn’t mean perfect.
I’m thinking of a broken switch lever where Armstrong or Aldrin used a pen to switch it.