Comments on Rocketpunk Manifesto: Spaceship Design 102: Life Support

Now that you mention it, yes. This was stressed. &...

2010-02-09T21:14:26.858-08:00

Now that you mention it, yes. This was stressed. "Breathe normally" was repeated a lot.

I've read about 'don't hold your breat...

2010-02-09T20:52:25.312-08:00

I've read about 'don't hold your breath' with respect to escaping from crippled subs, but it stands to reason it would apply to SCUBA as well.

I was wondering about if they told you to never ho...

2010-02-09T18:50:28.890-08:00

I was wondering about if they told you to never hold your breath. Because if you hold your breath and ascend, the air in your lungs will expand and blow them up. And this can happen from as deep as three (3) feet…

This is the reason why you cannot get SCUBA gear unless you are suitably certified.

Well it wasn't in a spacesuit, sadly, just a s...

2010-02-04T22:05:29.470-08:00

Well it wasn't in a spacesuit, sadly, just a standard wetsuit and tank/rebreather apparatus. Also the dive tank was fairly shallow (say deep enough for an Olympic diving competition) so there was no decompression issues.

However we did go in slow, with pressure equalizing pauses every four or five rungs. I actually had to climb back up a little at one point because of pressure in my ears that wouldn't clear. Went up four rungs, cleared it, and did the rest of the descent fine.

That's all the specifics I really remember. It was...

... Oh crap 18 years ago... thanks for making me feel old!

Anyways I do remember a pretty long lecture on precautions, and there always an instructor hovering at my shoulders. Once in there we had to perform a few simple "repair" tasks on a mock-up satellite. It was pretty fun, and over too soon.

Jean: (I always wanted to dive in a zero-G tank - ...

2010-02-04T21:57:01.043-08:00

Jean: (I always wanted to dive in a zero-G tank - in a spacesuit)...

Just curious: before you put that tank on, what instructions did they gave you? Because there are extremely important precautions one must take before breathing compressed air under water (very unobvious precautions, I might add)...

Windows in the deck might by too unnatural and win...

2010-02-04T20:49:45.420-08:00

Windows in the deck might by too unnatural and windows facing along the spin axis might cause dizziness. I would have an observation blister in the non-rotational section, however. Another possibility would be false windows. The cabins could have PC's with a flat screen display, screensaver could be a feed from an axis-mounted camera.

Thanks for the breathing mix information! On slee...

2010-02-04T20:42:29.980-08:00

Thanks for the breathing mix information!

On sleeping accommodations, I am thinking in terms of missions lasting weeks or months. I would greatly prefer ample viewports, even if there's not much to see during transfer missions, but I don't know whether viewports in a spin habitat are psychologically helpful.

I hope I put all my ducks in a three-dimensional g...

2010-02-04T12:26:15.939-08:00

I hope I put all my ducks in a three-dimensional grid.

emdx let me add my welcome. Absolutely priceless ...

2010-02-04T12:25:02.253-08:00

emdx let me add my welcome.

Absolutely priceless data. The only time I ever put on SCUBA gear was in the micro-g simulation tank at Hunstville's Space Academy. All this information is absolutely fascinating, especially the fact that hydrogen weakens metals over time.

On the subject of sleeping arrangements I don't think a closet is going to be very satisfactory. It would feel too "closed in" for one, and secondly it is not enough private space for an extended trip. There's a fine line between space economy and keeping the crew sane and not homicidal. However since the "bed" is just a sleeping bag starpped to the wall when needed and stashed away when not, and because in micro-g any space becomes a lot larger (a lot more volume is usable once gravity is not an issue) the cabins don't need to be all that much larger. The walls won't be bulkheads and the doors won't be hatches, I'm thinking thin curtain-like plastic sheets. As far as sound insulation there have bee some pretty good experiments with sound cancellation technology: emit a sound wave that is the exact opposite and they cancel out.

Pure oxygen spacecraft atmospheres are not a solut...

2010-02-04T06:59:05.130-08:00

Pure oxygen spacecraft atmospheres are not a solution. Recall the Apollo 1 fire. Pre-breathing O² to scrub one's nitrogen will remain for a long time.

As of putting-on skintight spacesuit, it's not really a problem; we put wetsuits on all the time, and have developped plenty of methods to do so, like using talcum powder or shampoo (as a joke, for a while, I was using K-Y jelly after I stumbled upon a big stash of it); but there is nothing that precludes having zippers or belts that can be closed/adjusted to help easing-into the suit.

* * *

The reasons why not using helium in a breathable spaceship atmosphere are many:

* Helium seeps out through anything. After a while, helium atoms sneak between metal atoms; so does hydrogen. Worse, hydrogen will alter the crystalline matrix of metals, weakening them. You don't want your pressure hull to dissolve, no? (and this is why the much-touted "hydrogen economy" will never take-off, given the enormous problems of transporting and storing hydrogen. In reality, it's just a big racket to keep the oil companies' stakes in everyone's transportation by having them buy hydrogen from gas stations rather than plug their electric cars at home - but I disgress).

* Helium is a tremenduous heat-sink. Astro-nuts breathing helium will get cold very quick, and they'll need to wear special insulating suits made of non-breathable foam in order to not freeze to death. Wearing a wetsuit - which does not breathe at all - on land gets uncomfortable very quick - no matter how big is the fetish value. Helium breathing atmospheres are a big problem for deep-sea divers; they lose so much heat trough their lungs that they have to use open-circuit hot-water heated wetsuits that are fed a continuous stream of hot water piped-in from the surface; if the stream stop, they have minutes to get back to their diving bell before freezing. The US Navy has experimented with portable plutonium heaters, but the sailors are understandably a little bit weary of strapping those to themselves...

* If someone suggests using hydrogen instead of helium, well, there goes your proverbial cigarette break...

* And lastly, helium (and hydrogen) are much less dense than nitrogen, hence the "donald duck" voice effect that, so far, no one has been able to solve. Cue the "ducks in space" jokes.

Thanks for the welcomes. Regarding "trains i...

2010-02-04T06:58:39.608-08:00

Thanks for the welcomes.

Regarding "trains in space", I recall the Apollo spacecraft, while being en route to the moon, being described as the "space train" on french-canadian TV... And why not? After all, the SM+CM+LEM ascent stage+LEM descent stage combination was coupled and uncoupled all the time during the mission... :)

Concerning accommodations, do we need huge staterooms? In zero-G, we can sleep "standing up" (recall the Skylab "bedrooms"), so one can effectively sleep in a closet; I suppose that 3 m³ will suffice for everyone and have room for luggage too. Compared to this, a duplex roomette is sumptuous accommodation...

But initially, I am sure the exitement will be so much that people won't mind spending a long time in an aircraft seat/couch with a good entertainment system screen (the "roomette window"), especially if zero-G will make it easy to go about the cramped quarters. Curtains could provide for privacy, and a white-noise generator close to the ears will easily muff-out ambient noise and help to sleep.

* * *

Regarding helium/oxygen mixes, helium is used in deep-sea diving because, unlike nitrogen, it does not induce narcosis (I SCUBA dive, too). With air, you can become impaired as "shallow" as 120 feet down. Whereas adding helium to your air (which becomes "trimix") can boost your unimpaired depth to about 250-300 feet. Helium alone can allow to go to about 500-600 ft, and with hydrogen (yup, breathing 95% H² and 95% O²), depth below 1000 feet have been attained. But in those cases, decompression times is measured in days if not weeks.

Gases won't stratify. Brownian motion will make sure that the lighter gas will diffuse and remain so. We always make fun of newbies who shake their tanks when they add oxygen to make "nitrox"...

Welcome to the comments threads! I believe that wh...

2010-01-23T07:18:28.228-08:00

Welcome to the comments threads! I believe that what you are suggesting is much like the cycler stations mentioned upthread.

There is no particular saving for rugged cargo, but potentially a big saving for passengers. They can make the short transfer hops in airliner type seating, minus all the bulky and heavy cabins and fittings, not to mention life support and shielding.

For fixed interplanetary routes, once the traffic ...

2010-01-22T11:05:17.645-08:00

For fixed interplanetary routes, once the traffic allows for it, it could be convenient configuring a "orbital convoy". What I means is, if we build a big habitat, with plenty of shielding, cargo-space, ample permanent life-support etc. etc, and we put it in an orbital permanent route between 2 or more destinations, you still have to expend plenty of delta-v for loading passenger and cargo, but you've only to expend a little for all the infrastructure.

Welcome to the comment boards! I first thought of ...

2009-12-26T10:39:22.957-08:00

Welcome to the comment boards! I first thought of the railroading analogy with respect to modular spacecraft - how cool to use the term 'consist' for the assemblage of a mission.

People may not consider rail sleeping accommodations as an example because the cultural association is not 'compact' but 'luxurious.' If you're thinking of utilitarian accommodations, as for a space crew, Pullman cars are not what comes to mind!

But in fact sleeping car accommodations are a good deal more compact than even the junior enlisted accommodations aboard a late 1960s vintage Newport News class LST, certainly more compact than JO accommodations.

Though one consideration is that you don't spend more than 2-3 days aboard a transcontinental train, compared to months at sea / in space. Also, a roomette feels a LOT less cramped because of the window!

I am impressed. This is the first space page I see...

2009-12-25T22:49:42.312-08:00

I am impressed. This is the first space page I see who mentions passenger rail accommodations.

People always overlook railroads for technological solutions; yet they have solved many important technological problems a century ago (distributed operations, communication protocols, ressource-sharing management). After all, 100 years ago, railroading was the high-technology of the day... And they had pretty acute problems to solve; like packing the maximum horsepower possible into a machine that could pass through a hole 10 feet wide by 15 feet high at speeds as high as 100 mph... (I am as interested by space as I am by railroads).

Regarding accommodations, for example, it is hard to beat the efficiency of a slumbercoach room. In single-passenger configuration, it packs a bed, a seat, a table, a toilet and a sink in less than 3m³ (yes, it's cramped); for a double passenger, make that 5m³ (but still cramped, and if one passenger wants to use the bathroom, the other has to go out in the corridor). Then you have duplex roomettes, where a single passenger has all the amenities in about 6m³, and so on, all the way to the double bedroom en-suite with two private bathrooms in about 20m³. All those were in widespread use 50 years ago.

One can also look at small sailboat configuration for examples of cramming accommodation in wierd spaces, but large ship accommodations can be deceiving. (I was actually very disappointed the last time I had a cabin on a tramp cargo; the space was very inefficiently used. In 50% more space than a double bedroom, there was no sofa/chairs at all; only two berths and a toilet that would have had a shower were it on a train).

I don't know enough about teleoperator technol...

2009-11-08T11:36:07.213-08:00

I don't know enough about teleoperator technology to have an informed opinion on waldo versus direct manipulation.

But even with cumbersome space suits, I have to say that EVA has worked out pretty well in terms of our capabilities. Even more than the ISS, the Hubble repairs are indicative, because it was never intended for on-orbit servicing.

It need not be an either/or. (Unless hard suits turn out to offer the best of both worlds.) Pods for convenient egress without complications like prebreathing a special mix, soft suits when real hands-on manipulation is called for.

And yes, hardsuit tech does lead somewhat inevitably to speculation about power armor!

I refute your torque wrench with the notion that y...

2009-11-05T11:38:59.249-08:00

I refute your torque wrench with the notion that you can't use it in zero gees anyway. The tools used in space grab on to the part and then twist and you don't get the sensation of a locked up part anyway.

Peripheral vision and feedback from whatever you're doing is important though. I would recommend a picture in picture arrangement and a screen significantly larger than the visor on your helmet. Cameras can be tuned to IR or UV spectrums with visible light overlays so you can see a lot better through the camera. There are touch/pressure sensitive robotic arms being tested now. They also have a voting system control scheme in autopilots whereby if the pilot does something stupid, the autopilot can outvote him. Applied to grabbing stuff, the arm would stop at a predetermined pressure and ask "You are about to crush object. Continue?"

Waldos may not even be necessary in the future. Project NATAL uses cameras to recognize actions by the user and then translate them into game commands. A room, a little over 2 meters in diameter could house a harness for an operator plus projectors and a feedback suit (like the rumble packs in game controllers). The robotic avatar could then pipe back data to give the operator full surround sensations.

Follow this argument to its logical conclusion and...

2009-11-05T11:09:19.533-08:00

Follow this argument to its logical conclusion and you wouldn't need a suit or a pod at all, just remotely-operated robots. However I think that, like an air force made entirely of drone, a space workforce made entirely of robots is likewise unlikely, maybe even unfeasible, for many reasons.

1/ Communication delay: as indicated in the paper linked previously (sorry for broken link, just copy-paste URL it should work) there is a latency between command input and remote manipulator execution. The further removed the operator is from the robot, the more the latency is pronounced, and the greater the errors.

2/ Feedback: It is one thing to try and use a torque wrench and feel resistance in your arm as something locks up, and other to have a control pane beep a warning at you. A remote operator has to do things almost solely by sight, when the human mind is very much conditioned to react to physical rather than optical stimuli (space sickness is a conflict between vision and inner ear, for example. That's not even mentioning what a fixed camera would miss when our constantly roving eyes are naturally drawn to motion and unexpected sights. That cracked bolt flying away? a camera focused on a task will miss it, an astronaut will see it through peripheral vision and clue in right away to a problem.

While perhaps the US Air Force is too reticent to use drones, let's not get into an opposite mindset of excessive automation. Even robotic factories employ human workers to monitor the process, intervene in emergencies, and do the delicate work that requires a human touch and difficult to program. There's probably a good compromise, and I think that the hardsuit fits into that compromise a lot more nicely than a pod, which indeed could be completely replaced by a robot since it removes a lot of the reason you'd want a human on-site by isolating him in a cabin. At this point, does it matter the control cabin for the arm is in the pod or back on station?

There is an assumption that you will need some sor...

2009-11-05T09:24:08.018-08:00

There is an assumption that you will need some sort of mechanical assistance with the hard suit limbs. If you stick your arm inside, that mechanical assistance has to be exterior. That makes the arm much more bulky. If you don't put the arm in there, then you can fill the arm with the mechanical stuff and have utility beyond that of the human arm (like a spinning wrist.

Barring the full waldo, a glove, with tactile pickups, could transmit the hand's intents to a robotic hand, which may have a built in camera for close up inspections.

I think that the complaints about waldos and robotics are the same complaints that the Air Force has about unmanned recon vehicles. It is taking jobs away from officers and putting it in the hands of enlisted men with minimal training. With a little more progress in feedback, VR simulation and some robotics, the whole issue of tele-operations can be solved.

As far as sphere and waldos: that's essentiall...

2009-11-05T08:34:43.168-08:00

As far as sphere and waldos: that's essentially what Rick was talking about when he said a 2001-type pod. They were spherical. And had Waldo arms... so yeah.

My argument for the hardsuit over the pod is it would be smaller than a pod, since it is form fitting to the astronaut rather than a big sphere, two, that ergonomically it would feel more natural to the user, since there is not interface to speak of: you'd move more naturally, and though constrained, less so that in a pod.

http://www.osti.gov/bridge/servlets
/purl/459340-C0yAX0/webviewable/459340.pdf

This document illustrates some of the issues with remote manipulators, the first one being that it takes a lot of room to set up waldo systems. In case of a hardsuit there is no separation between the controller, the controls, and the manipulators. As I stated, it is a lot more compact. Since it is also fitted to form, it is probably more natural for a human operator. In a pod, he will have to worry about piloting the craft *and* using the waldo controls. Or you need a pilot and mechanic, which causes the pod's size to increase even further. In the suit, the astronauts movements can control both piloting and manipulation in a more natural manner.

Sorry for the misunderstanding: no, Russians use s...

2009-11-05T08:21:52.065-08:00

Sorry for the misunderstanding: no, Russians use standard suits, but rather than American suits which have to be assembled on the astronaut, they get into theirs by going in through the backpack. It's still a low pressure soft suit. It was merely arguing their way of getting the suit on would apply to a hardsuit.

Once you get into hard suits, is there a good reas...

2009-11-05T08:17:36.410-08:00

Once you get into hard suits, is there a good reason to actually have your arm inside the suit's apparent arm? Wouldn't it be easier and more functional to have a robotic arm controlled by a waldo attached to your own arm? Then you just need sort of a spherical pod with life support and not have to worry about sealing joints.

"Going in another direction, I think there...

2009-11-04T22:43:19.596-08:00
"Going in another direction, I think there will be a place for what I call space taxis: small, simple pressurized 'short range' transfer vehicles for a few passengers." - Rick

Which probably would lead to the age old Sci-Fi story of the stranded Lifepod which is effectively the Life Boat IN SPACE!.

And from Jean Remy's apparent favoring of Hardsuits, I admit I was kind of surprised. I was thinking of a powered Hardsuit that utilized an exoskeleton-like frame to help with the movements since traditional hardsuit designs are rather difficult to move using human strength alone. I had figured that there would be strong arguments against such an idea. And to be honest, even though it is as scientifically correct as any Star Trek or Space Ghost episode, the Mech nut within me can't help but wonder and hope if such powered hardsuits would lead to some interesting combat machine designs.

Anyway, getting back to the original blog post topic, one could potentially predict that like Propulsion Drives, Reaction Mass and Fuel storage, and on board Power Generation, reducing the overall mass of the various life support systems to increase overall payload allowance is going to be extremely difficult to perform in the near or even mid-future. Especially considering how delicate its possible primary cargo (i.e. crew and passengers) are when traveling in between planets and orbit trajectories, let alone interstellar.

- Sabersonic
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The Russians use hardsuits? I just realized that I...

2009-11-04T20:50:26.221-08:00
The Russians use hardsuits? I just realized that I don't know the first thing about Russian EVA practice. I'm familiar with Soyuz images, but I don't recall ever seeing an image of a cosmonaut doing a spacewalk.

Going in another direction, I think there will be a place for what I call space taxis: small, simple pressurized 'short range' transfer vehicles for a few passengers.

The problem with normal suits is the ballooning. T...

2009-11-04T11:59:55.310-08:00
The problem with normal suits is the ballooning. The problem with skinsuits is they will be a pain to put on. You'll need to dab your negative spaces (underarms etc) with some putty to avoid the skin to balloon out in the interstitial space.

Hardsuits are actually a good compromise between 2001 pods and normal suits or skinsuits. I'm thinking of suits like deep undersea workers use, perhaps coupled with exoskeletons. There are already a lot of exoskeleton suits being tested and prototyped. They would be smaller than the pods, and more natural for human operators to use. They would be easier to shield against radiation than a suit, and able to go in places a bigger pod might not get to. You wouldn't put it on like an american suit, as much as enter it.

The Russian and European suit designs generally have the backpack build like a hinged door, and you slide into it from the back. You can even store the suits "outside" with the backpack fitted to an airlock. Because it is a hardsuit, you can use the same mix (whether O2-N or O2-He) as the station/ship.