[HN Gopher] NASA's new sleeping bags could prevent eyeball 'squa...
___________________________________________________________________
NASA's new sleeping bags could prevent eyeball 'squashing' on the
ISS
Author : CapitalistCartr
Score : 101 points
Date : 2021-12-13 12:46 UTC (1 days ago)
(HTM) web link (www.engadget.com)
(TXT) w3m dump (www.engadget.com)
| Pxtl wrote:
| > Dr. Levine discovered SANS by flying cancer patients aboard
| zero-G parabolic flights. They still had ports in their heads to
| receive chemotherapy, which gave researchers an access point to
| measure pressure within their brains
|
| what
| avs733 wrote:
| I would have loved to be on whatever panel read and approved
| that grant. Obviously this is a brilliant methodology and a
| wonderful science hack, but how stoned did someone get that
| 'zero G cancer patients to tap their brain fluids' came out.
| supperburg wrote:
| >by the time NASA is ready to go to Mars
|
| Don't hold your breath.
| germinalphrase wrote:
| Technical issues aside, why would they even want to?
| rtkwe wrote:
| Humans are still generally better than just having a robot
| there because they're both more flexible and capable of
| problem solving. Maybe for the same money you could get
| enough robots there to make up the gap but sending humans to
| Mars is sexier and attracts more money than you could get for
| the robot missions. Then even if we never actually go
| 'preparing' to go to Mars attracts ongoing money for studies
| on the ISS and for sending robotics missions.
| jzig wrote:
| I guess you could say staying in space long enough gives you SANS
| vision.
| AcerbicZero wrote:
| This is endemic of the problems at NASA. The concept is likely
| sound, and the problem likely needs to be solved, but doing it in
| such a tiny and insignificant way.....spin the spaceship, dont
| vacuum the space people.
| jimkleiber wrote:
| How would one dock with a rapidly spinning spaceship?
| T-A wrote:
| Elegantly
|
| https://www.youtube.com/watch?v=0ZoSYsNADtY
|
| or heroically:
|
| https://www.youtube.com/watch?v=a3lcGnMhvsA
| whoisburbansky wrote:
| One would dock to the axis of rotation, I would think,
| spinning up your spaceship to match station spin?
| HPsquared wrote:
| The docking port would need to be coaxial with the axis of
| rotation.
| nofunphil wrote:
| a docking station at the central point that the ship rotates
| around
| srdev wrote:
| Spinning the spaceship is a pretty hard problem. There's all
| sorts of constraints on how fast you can spin it for a given
| radius, and you have to spin it fast enough to be useful. The
| end result is that you're looking at a pretty huge spaceship
| that will take a lot of power to start spinning. Its not
| unreasonable to look at a smaller-scale solution given a world
| of limited budgets.
| samwillis wrote:
| Scott Manley did a video looking at this, it's a good and
| informative watch:
|
| https://youtu.be/nxeMoaxUpWk
|
| The gist is that is actually doable at the same(ish) scale as
| the ISS. Bigger is better but we can do it at a radius as
| little at 40m.
| frosted-flakes wrote:
| The whole point of the ISS is that it provides a stable zero-G
| environment for experiments. Spinning it would be counter-
| productive.
| dredmorbius wrote:
| It's possible to spin on section and not another. Vibration
| would likely be an issue, but already is.
| garaetjjte wrote:
| How to walk from fixed to rotating section then?
| dredmorbius wrote:
| Via the hub.
|
| https://yewtu.be/watch?v=0iiXUeil5fQ
|
| https://yewtu.be/watch?v=nxeMoaxUpWk&t=11m6s
| thatguy0900 wrote:
| Is the problems of nasa that they don't have an unlimited
| budget? Why make a experimental rotating artificial gravity
| spacecraft when a fancy sleeping bag will do the trick?
| Valgrim wrote:
| We should experiment on rotating artificial gravity anyway,
| if only to expand our knowledge of space colonization:
|
| https://www.nasa.gov/careers/our-mission-and-values
|
| > Mission: Lead an innovative and sustainable program of
| exploration with commercial and international partners to
| enable human expansion across the solar system and bring new
| knowledge and opportunities back to Earth. Support growth of
| the nation's economy in space and aeronautics, increase
| understanding of the universe and our place in it, work with
| industry to improve America's aerospace technologies and
| advance American leadership.
|
| But I agree that it should be a completely different mission
| than the International Space Station.
| Out_of_Characte wrote:
| using centrifugal force would require a complete redesign and
| billions of dollars. Whereas the ISS space station is for a few
| people for a few months and mostly for research.
|
| sophisticated space stations would have to wait untill a
| turning point in profitability is reached. Space elevators are
| still in the realm of science fiction and are on the edge of
| theoretical feasability
| samwillis wrote:
| Agree this is a sound solution for now however the the ISS is
| currently only approved for service until 2024 (this will
| clearly be extended) and plans need to be made for its
| replacement.
|
| With the (moderately) high probability that the SpaceX Star
| Ship will succeed and go into active service in the next few
| years the cost to orbit is going to drop significantly. There
| is an opitunity soon to rethink what a space station is.
| Realistically the internal area of a Star Ship could make a
| space station in the same vain as ISS, and would be "cheap".
| But we could also feasibly construct a rotating station with
| the use of Star Ship.
|
| Space is about to undergo a transformative change in how
| people approach building in it.
| starlust2 wrote:
| Sierra, Axiom, and Blue Origin are all working on
| commercial successors to the ISS.
|
| Axiom's first modules will launch 2024ish and initially be
| connected to the ISS.
| Out_of_Characte wrote:
| So far, most space endeavours are related to science in
| some way. which is problematic because there is little to
| no return on investment. also, everything we have and
| consume is on earth. I can't think of many products which
| are low in mass but extremely high in value and could
| benefit from the only properties of space we control right
| now; weightlessness and orbits.
|
| To me, cheaper rockets could only help building a future
| space elevator which would reduce costs significantly but
| we would still need something to do in space.
|
| So what do you think the first economic incentive will be
| to enrich society?
| tokai wrote:
| I know space is at a premium on a space craft. But wouldn't it
| still be simpler just to have a sleepingbag that rotates around a
| center by the upper torso? Seems overengineered to sleep in a
| vacumbag.
| rtkwe wrote:
| That would push some down into the feet but also accelerate
| some up to the head. In addition that's a lot of space in a
| pretty cramped area. Then you have to mount it so it doesn't
| induce vibrations on the space craft which is an issue they
| already fight with the existing exercise equipment. On top of
| all of that you're creating pretty sizable gyroscopes that you
| need to spin up and down requiring a counter force from
| somewhere.
| eminence32 wrote:
| Maybe I've misunderstood your idea, but it seems to me that a
| vacuum sleeping bag is _less_ complicated than a sleepingbag
| /bed that constantly rotates its occupant
| tokai wrote:
| well a vacum sleeping bag is a motor plus more (and the bed).
| A rotating bed is just a motor (and also the bed). But yeah
| it's probs not any better.
| errcorrectcode wrote:
| I'm curious about nocturnal cerebral edema and its potential
| relation to Alzheimer's and dementia. IIRC, some of the brain's
| cells may change size to accommodate what could be considered a
| "flushing" routine to remove detritus but tangles of tau and/or
| ABeta don't want to go. Perhaps exercise and/or spaceflight could
| dislodge them.
| penisverse wrote:
| Maybe related
| https://alzheimersnewstoday.com/2021/10/05/hyperbaric-oxygen...
| TheCoreh wrote:
| Why can't we tether the spaceship that carries the astronauts
| with a separate spaceship that carries the cargo (that will be
| only needed on mars) via a set of long, thin cables (to act as a
| counterweight) and spin the two around their joint center of
| mass? That solves the problem of needing a really large ship to
| make the rotation not uncomfortable, and allows for artificial
| gravity
| rbanffy wrote:
| We could also use an inflatable module with a centrifuge inside
| it. The smaller diameter would make coriolis forces worse and
| walking would be tricky, but, at least, your body would spend
| some time under some gravity.
|
| Putting it inside a large inflatable makes it easier to pack
| and solves a problem with rotating seals and the need to stop
| rotation when a spaceship is docked (because an internal part
| is rotating, but the rest of the craft is static). One issue
| that it doesn't solve is that it'll doubtlessly pass some
| vibrations and some oscillations to the rest of the craft, so
| any microgravity experiments will need to account for that.
| jerf wrote:
| This is one of several things I hope to see if SpaceX succeeds
| in crashing the cost/kg to orbit. I think it's difficult to
| overestimate how hamstrung our space program has been by the
| sheer expense of mass. New technology was certainly always
| going to be necessary, but there is so much that would be
| easier and/or _possible_ if we could just get mass to orbit and
| weren 't counting every gram.
|
| At current prices, it's hard to justify lifting dead weight
| just to spin.
| 6gvONxR4sf7o wrote:
| The issue is probably the strength of the structures involved.
| kamray23 wrote:
| Starship weighs 1300+ metric tonnes. Accelerating to earth
| gravity, the cable will have a tension of 1.3 MN. On the
| other end the counterweight has to be of roughly equal mass
| by way of not being able to launch anything heavier (so prob.
| another starship), meaing that the barycentre will be roughly
| in the middle, and the counterweight applies a second 1.3 MN.
| The total tension the cable is under is going to be 2.6 MN,
| well outside any single cable today. Taking a comfortable
| velocity of 1 rpm, and calculating a radius, we get a cable
| 894 meters long. This is right in the comfort zone as far as
| difference in force over your body and disorientation from
| spinning are concerned. Our strongest cables, made of Aramid
| (which degrades too quickly because of radiation, but
| ignoring that) is going to be 58 cm and have a weight of 2.2
| metric tonnes. Since we actually need twice the cable, it's
| actually 4.4 tonnes. A similar cable made of carbon fibre or
| another such element will give us a launch weight of 430+
| tonnes (close to the mass of the ISS), which rules basically
| anything but polymer fibres out. The R&D funding that would
| have to go into developing the cabling and methods of
| shielding it and preventing MMOD, solar, or GCR degradation
| is astronomical. It's way cheaper to just make a special
| sleeping bag or two.
| hexane360 wrote:
| I agree it's impractical, but I believe you're double
| counting the force on the cable. Each end of the cable
| pulls with 1.3 MN, which means that the cable itself can be
| in static equilibrium (in the rotating frame of reference).
| The same is true if you hang a 1.3 MN space station from
| the ceiling. The space station pulls down with a force of
| 1.3 MN, while the ceiling pulls up with a force of 1.3 MN.
| Aerroon wrote:
| Can't we use multiple cables then? There are ships that can
| lift over 10,000 tons with their cranes. Some of these are
| decades old.
| 3pt14159 wrote:
| We can. It's been written about for decades. It's just
| expensive.
| londons_explore wrote:
| But _why_ is it hard or expensive. These spacecraft can
| already withstand earth gravity, because we built them here
| on earth and they didn 't collapse during construction. They
| typically already have lifting points to lift them with a
| crane too.
|
| Cable is cheap and light.
|
| Getting the whole lot spinning can be done very slowly over
| many days with the same ion thrusters that are used for
| stationkeeping. Total delta-V isn't very high. Total fuel
| used isn't very high either.
|
| The only disadvantage really is that you lose most of the
| benefits of zero-G. for example, long running experiments
| requiring zero G. You also start to need walkways and paths.
| The ceiling of rooms becomes dead unusable space. etc.
| Docking new spacecraft requires stopping the spinning, which
| takes many days. Comms antennas and solar arrays get more
| expensive.
| throwaway0a5e wrote:
| >The only disadvantage really is that you lose most of the
| benefits of zero-G. for example, long running experiments
| requiring zero G. You also start to need walkways and
| paths. The ceiling of rooms becomes dead unusable space.
| etc. Docking new spacecraft requires stopping the spinning,
| which takes many days.
|
| For a one way trip to "elsewhere" none of that matters
| much.
|
| We'll probably see this approach investigated more fully
| when a one way trip to elsewhere seems more likely.
| JoeAltmaier wrote:
| TO dock you have to spin down and then spin back up again?
| It's a hard problem.
| 3pt14159 wrote:
| I actually agree with your underlying urge: space travel
| should be pleasant! But what separates out engineering from
| science is essentially economics. In science we don't know
| the scale a discovery will make until we've made it. Before
| nuclear weapons how could we know that studying these tiny
| atoms would essentially end total war between major powers.
| With engineering smart people looked at the costs and said
| something like:
|
| > We're 99.9% sure this is going to be >2x the alternative
| and it's not worth it.
|
| Just off the top of my head costs that go up:
|
| - Instruments (lol, our cameras now need faster f-stops)
|
| - _Every_ need now needs to be met during the spinning
| state and the non-spinning state. (lol, Frank you used the
| gravity toilet in the middle of the night but we stopped
| the spinning state yesterday)
|
| - Harder to maintain, since crew needs to lose angular
| momentum as they travel along the bridge and they can't
| toss things around as easily.
| kamray23 wrote:
| Depends on the situation, though usually because of the force.
|
| Spinning a spaceship around a point with a long cable, you
| obviously produce a (fictitious if you're pedantic) outward
| force, that's kind of the point. For that fictitious force to
| exist though, that very force acting on the spaceship must be
| counteracted by an equal and opposite reaction force provided
| by your cable, creating the action-reaction pair required for
| tension. This much is obvious. The problem arises when you
| think about how large that force is.
|
| To generate an apparent artificial apparent gravitational
| acceleration of 1 G for the occupants, the entire ship must
| experience the same spin and thus the same acceleration. That's
| the source of the problem, the force you're counteracting is
| the same as the weight of the ship on Earth. What is being
| asked here is to hang a loaded spaceship from a building with
| cables. That might work for smaller spacecraft, whose mass is
| measured in metric tonnes, but it won't work for anything
| larger. You can get incredibly strong and light cables out
| there, but one capable of functioning in the space environment,
| light enough to launch, and strong enough to counter the tens
| of meganewtons of force required from it is going to be more
| difficult to find.
|
| Not only that, but you need to consider the counterweight as
| well. Because of the cable, the tension force total is also
| dependent on the acceleration of the counterweight. Since
| launching a heavier counterweight than an entire habitable ship
| is probably out of the question, you'll probably need twice as
| long a cable and experience roughly twice the force required
| just to lift the ship on earth. Needless to say, that's getting
| a bit out of the realm of current space capability. Not to
| mention the immense size you'd need to make a ship like this
| for the situation to not cause immense discomfort.
| iso1631 wrote:
| Even 0.1G would do wonders with things like stopping blood
| pooling and moving co2
|
| Two starships at 200t each linked by 10 cables would need
| 40kN each, a 5cm diameter cable, at 2.5kg/m a 1km cable,
| you'd need need 25 tons of cable, about 10% of the cargo
| capacity. You'd be well under 1rpm
|
| https://www.engineeringtoolbox.com/wire-rope-strength-
| d_1518...
| throwaway0a5e wrote:
| >That's the source of the problem, the force you're
| counteracting is the same as the weight of the ship on Earth.
| What is being asked here is to hang a loaded spaceship from a
| building with cables.
|
| We're talking about 10,000-100,000lb (i.e. just the crew
| module) depending on mission profile and the craft in
| question. You can handle that and more with commodity wire
| rope and hardware. Whoever we're sending to Mars will
| probably appreciate having a useful tow rope on Mars anyway
| so it's probably wise to just use a boring old steel cable
| rather than something that weighs 3lb but isn't up to the
| rigors of surface use. Remember, we're using "needs to go
| into space" margins here, not "overhead lifting on earth in a
| jurisdiction where OSHA matters" or "what makes Redditors
| sleep at night" margins here so you're not going to need a
| behemoth of a cable. Furthermore, you don't even need to
| generate 1g, just enough to not cause health problems and
| greatly simplify craft design.
| kamray23 wrote:
| Yeah something that small is going to be fine. But the ISS
| will _not_ be. It 's 440 metric tons, generating 4.4 MN of
| force on a cable. That's not going to spin.
|
| And you're sending something to Mars here. In the ideal
| case we'll be sending six worth of supplies at the same
| time per person per ship. The amount of people permitted by
| NASA's guidelines on long-term habitation on a ship based
| purely on volume range from 1 for smaller ships to 30 for
| something the size of Starship. Hauling everything they
| need is not going to be below 50 metric tonnes by any
| means. We can probably spin as much as we like here, near
| the Earth, but anything further away is going to have ropes
| the breaking strength of which is again measured in
| meganewtons and the width of which is going to be around
| half a meter. Making that out of steel for the kind of
| cable you'd need for comfortable spinning (~1 rpm, 1.6 km
| of cable) is not going to space any time soon.
|
| At the very least 6 months of food is required for the crew
| module, or some complex procedure of periodic de-spin &
| rendezvous with a cargo vessel. The kinds of missions NASA
| has been planning are 30 months in overall length if
| everything goes well, though 24 of that is not required to
| be accessible during transit. Spinning again in low martian
| orbit is going to be quite feasible, once you jettison all
| of your life support and such and instead do very frequent
| cargo stops.
| panick21_ wrote:
| Most people are giving technical explanations. But actually its
| very non-technical and deliberate. For some historical reason
| astronaut office space biology gained primacy in the NASA after
| Apollo. The reason they never seriously considered artificial
| gravity is because THEY WANT TO STUDY MICROGRAVITY. The whole
| goal of station is to solve micro-gravity research and human
| medical research is the most important of those.
|
| Its not a goal of the station to figure out how to most
| efficiently keep humans alive in space. Its simply a great
| reason to stay in LEO and do research for 50-100 years.
|
| There is a reason many space advocates since the 60s have
| pushed for artificial gravity research and almost nothing has
| been done. Its political. The technical problems are
| approachable and solvable but it has not political base
| unfortunately.
| mstank wrote:
| Is there a good list of major health issues associated with space
| flight?
|
| Would be interesting to see what still needs to be solved for
| multi-year stays.
| toomuchtodo wrote:
| https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_h...
| thedudeabides5 wrote:
| Not comprehensive, but link between radiation - viruses -
| cancer here
|
| https://www.ted.com/talks/madison_campbell_viruses_in_space_.
| ..
| ComputerGuru wrote:
| ISS doesn't have much radiation. It's not the moon.
| viburnum wrote:
| Yeah, the ISS is barely even in space. You can go that
| far on a train before lunch.
| xwdv wrote:
| IMO the problems of living in space are so numerous that unless
| we can seriously come up with a good general solution for
| artificial gravity we probably shouldn't even bother with the
| idea of being in space for anything longer than a flight to some
| celestial body. Why has it taken so long?
| euroderf wrote:
| Sleeping in zero G. Another issue is that CO2 won't disperse.
| IIRC from a discussion on Henry Spencer's sci.space, there is a
| fan at every sleep station.
| tzs wrote:
| Why won't CO2 disperse there? I'd expect diffusion to be
| sufficient to keep the CO2 concentration fairly uniform
| throughout the station.
| ComputerGuru wrote:
| I think it's more about local pockets over temporally short
| periods of time. Gravity probably plays a role in kicking off
| the dispersion process by moving them from their initial
| place of production (where you exhale) so it doesn't just
| cluster there.
| labster wrote:
| Gravity _definitely_ plays a role in convection, which is
| the main form of dispersion. The air one exhales has
| different composition -- more CO2, more water -- which
| means it has different buoyancy. Usually, this means the
| parcel of air rises here on Earth, but falling of your face
| is fine too. No gravity means no convection. Without wind
| to cause turbulence, mixing is really slow, leaving
| molecular diffusion as the only process. Remember, that's
| random, and CO2 will still accumulate near the point source
| with a Gaussian distribution.
| sephamorr wrote:
| Diffusion is definitely not sufficient--natural convection is
| usually sufficient to do this on earth, but gravity is a
| requirement for most natural air convection. Interestingly, a
| surprisingly large percentage of a spacecraft's power draw is
| spent just on air circulation (other conditioning adds as
| well).
| blockwriter wrote:
| I'll go to space when there are mattresses and the ice cream
| isn't plaster.
| DarthNebo wrote:
| The solution that sprung in my mind was akin to an artificial
| gravity simulator ring, slowly spinning beds arranged like a
| flower petal.
| LeifCarrotson wrote:
| That works, but the necessary radius is larger than anything we
| have in space right now.
|
| The vestibular system would be so confused you'd quickly
| develop motion sickness. Kids with low-viscosity fluid find the
| Scrambler at the carnival fun, adults can have fun for a
| while...but nobody I know of falls asleep on it.
|
| Here's a cool page discussing appropriate radii and spin
| velocities for artificial gravity:
|
| https://www.artificial-gravity.com/sw/SpinCalc/
|
| TLDR: A space habitat with artificial gravity should have the
| rotating section on a cable or truss at a radius on the order
| of 100m or more!
| anarchy8 wrote:
| NASA spends a lot of money trying to negate the health impacts of
| zero gravity, one wonders whether or not that money / science
| would be best spent in outfitting the next space station with a
| rotating section? Then we could prove that that solves the
| problem.
| conaclos wrote:
| Remind me of Misha who goes practically blind during his trip to
| Mars in series Away.
| viburnum wrote:
| Really the solution is to just send robots.
| gruez wrote:
| > vacuum cleaner-like suction device is then activated that draws
| fluid toward the feet, preventing it from accumulating in the
| head.
|
| How does that even work? The liquid is accumulating inside the
| head. How would pulling a vacuum (presumably outside the body, in
| the sleeping bag) help? If anything the vacuum would force liquid
| to the head by squeezing liquid from the body.
| supperburg wrote:
| Create low pressure around the legs, they puff up with blood
| which means less blood in other parts of the body. If you need
| a demonstration then google "penis pump"
| lumost wrote:
| Iirc there is a lot of debate on the minimum g level required
| to avoid negative effects. Spinning people tends to make them
| uncomfortable and nautious.
|
| However, I'd be quite curious if the g level is actually very
| low. You could have a small gently rotating section of a
| station.
| dotancohen wrote:
| > small gently rotating section of a station
|
| A small rotating section near the center would have
| extremely uncomfortable tidal effects. You want to be as
| far as possible from the fulcrum to reduce the tidal
| effects.
| rbanffy wrote:
| You can probably just lie down and sleep though. The
| tidal effects would be interesting, but I'm not sure
| they'd be uncomfortable. Walking would be more difficult,
| as you'd feel you are about to fall on your face (or
| back) but I don't think it's something one wouldn't be
| able to get used to.
|
| Wouldn't work with the 4.5 m size limit of the current
| ISS modules, it's barely doable with a Starship-wide
| module, but seems totally doable with inflatables.
| Bigelow was designing 12m+ wide modules and that was a
| limitation of the rocket fairing that was launching it.
| With, say, Starship, the module could be much wider.
| lumost wrote:
| How fast does it really need to spin? I'm not sure there
| have been any studies on 1/128g or less. In a 4.5 meter
| section 1/128g would only be 1 rotation per 30 seconds.
| dogma1138 wrote:
| The issue is that at the average height of the astronaut
| the rotation speed at their head would be half of that at
| their feet given the 4-5m modules we can launch.
|
| I don't know what is the maximum difference that would be
| tolerable but it's not 2x for sure.
|
| So to get it down to single digit % you are looking at
| 200M+ or so in diameter.
|
| If it's just for sleeping and liquid pooling at the back
| won't pose a health risk then if they are lying down the
| diameter can be much lower but you are still probably
| looking at 15-20M which might be possible with inflatable
| modules I think 3.5-4X expansion would be quite possible
| with the existing inflatable modules we have.
| rtkwe wrote:
| The tough part with making it small is the smaller the
| torus or device the larger the gradient of forces along a
| riders body which can be disorienting. Any useful G level
| and comfortable size would likely be larger than any
| existing module.
| e12e wrote:
| I guess it sucks on the "skin balloon" by creating low pressure
| around the lower body, thus "inflating" the legs (think swollen
| feet).
|
| But I'm a little surprised that would work. Another way to look
| at it, would be that the higher pressure on the head and torso
| "squeezes" fluids down, like a water balloon - squeeze one end,
| and liquid goes to the other end?
| xuhu wrote:
| There are veins for other liquids, just like there are for
| blood. The liquids don't lie around everywhere under the skin.
| michael1999 wrote:
| Think iron lung, not shrink-wrap.
| rtkwe wrote:
| They've been experimenting with this on the Russian side of the
| station for years. Their version is semi rigid and creates low
| pressure around the astronaut's legs so the natural pressure in
| the body and the air pressure of the ISS on the upper body and
| face squeeze the blood into their lower extremities away from
| where it pools naturally in micro gravity.
|
| http://www.astronautix.com/c/chibis.html
|
| https://blogs.nasa.gov/ISS_Science_Blog/2015/06/02/rubber-va...
| samizdis wrote:
| Archive link for anyone irritated by engadget's cookie settings
| nightmare:
|
| https://archive.md/z4czx
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