Hariven-class Free Trader

So, I got a request from a reader for a few specs on the Hariven-class free trader. Well, why not?

(Sadly, they were imagining something like Vaughan Ling’s Planetes-inspired debris collector with comparable dimensions, capacity, etc. Sorry to say it, but that ship? Had some style. The Hariven? Really doesn’t.)


Operated by: Desperate free traders, just starting-out bands on tour, your sketchy brother, refugees, space hobos, and anyone else who can’t afford a better ship.
Basic freighter.
Under open-source license; produced by multiple manufacturers, most of whom would prefer not to admit it, along with various backyard fab shops.

(And when I say “desperate free trader”, I don’t mean, say, the people who fly around in a Firefly-class in Firefly. Those people, in this verse, own something like a Kalantha-class. This is down from there at the true ass end of space travel.)

Length: 46m, of which 30m is the hold.
8m (not including radiators)

Gravity-well capable: No.

Personnel: 3, as follows:

Flight Commander
Flight Director
Flight Engineer

(This assumes you’re following the typical regulations which require – since the Hariven has no AI, and only dumb automation – that at least one qualified person be on watch at all times, hence a minimum of three. In practice, a Hariven can be flown by one and very often is, if they don’t mind violating the rules of navigation of every halfway sane polity in space.)

Drive (typical; may vary from build to build): Nucleodyne Thrust Applications “Putt-Putt” fusion pulse drive.
 Deuterium pellets.
Cruising (sustainable) thrust:
 0.6 standard gravities (0.56 g)
Peak (unsustainable) thrust:
 1.2 standard gravities (1.12 g)
Delta-v reserve:
 (Not yet calculated, but limited; if you’re flying a Hariven, you ain’t going brachy unless you devote a lot of your hold space to extra tanks. Be prepared to spend much of your voyage time on the float.)
Maximum velocity:
 0.02 c (based on particle shielding)


Not supplied as standard, but buy some. You’re gonna need ’em.


Orbital Positioning System sensors
Inertial tracking platform
Passive EM array
Short-range collision-avoidance and docking radar



Other systems:

Omnidirectional radio transceiver
Communications laser
Whipple shield (habitable area only)
Mechanical regenerative life support (atmosphere/water only)
Algiprote vat
2 x information furnace data systems
Sodium droplet radiators

Small craft:

Not supplied as standard, but a common as-supplied variant adds a partition to convert part of the forward hold into a bay with docking clamps suitable for many surface-to-orbit vehicles.


It’s a classic tail-lander layout of the crudest form: a 30m steel box welded on top of an 8m steel cylinder welded on top of a cheap fusion pulse drive, the latter two surrounded by pellet containers. It couldn’t look more brutalist/functional if it tried. At least most Hariven owners try to give it a bright paint job.

The hold is up front, a big steel box roughly the size of eight standard shipping containers. (Indeed, sometimes it’s made from eight standard shipping containers.) Putting it right for’ard has the advantage of simplifying construction greatly – all the machinery is at one end – and giving Hariven captains the assurance that if they ram their junker into anything accidentally, at least there’s 30m of other stuff between them and whatever they hit.

The hold opens up along its entire length on the port side to permit access. Responsible captains who convert their Hariven for passenger transport (the aforementioned touring bands, refugees, and space hobos, for example) by attaching deck partitions inside the hold and adding canned air have these welded shut. Less responsible captains simply pray for a lack of wiring faults.

The habitable section (the cylinder at the back) is wrapped in auxiliary engineering machinery and fuel storage, to the point that it’s only 4m in internal diameter. (If you need to fiddle with most of the engineering systems, you’re going to need a drone, or to take a walk outside.) It’s divided into four decks, from the bow down:

The bridge, which shares space with most of the avionics;

A small living area, which contains the food vat, a tiny galley, the inner door of the airlock, and any luxuries you see fit to squeeze in there. Like chairs;

The crew quarters, which means four vertically-mounted sleep pods, and maybe room for another luxury or two if they’re small;

And a tiny workshop, for any repairs that need doing.

That all sits right on top of the shadow shield and the business end of the drive. If you need to adjust anything below that – well, hope you brought a drone.

But enough of this. You buy this ship, treat her proper, she’ll be with you the rest of your life.

Ain’t sayin’ how long that’ll be, mind.



40 thoughts on “Hariven-class Free Trader

  1. You’re right: the Hariven isn’t like Ling’s collector…she’s better (I know, she ain’t much, but she appeals greatly to my minimalist, space hobo, aesthetically primitive, sensibilities).

    If I were meandering ’round your universe (hauling other people’s crap from A to Z) it would be in a Hariven.

    Thanks for the quick and thorough response…you did me a solid and I owe you one. -Henry

  2. Here’s some advert from Abner Munson, owner/operator of the Hariven-class, ‘Make Do’…

    “Yeah, she ain’t pretty, but she’s soild; she ain’t fast, but she’s reliable: I’ll get your crap from ‘here’ to ‘there’, no worries.”


    “When you gotta make do with what you got (little currency) and your crap has to get there (eventually), let Munson’s Hauling be your go-to solution. Moving crap is what I do. Moving crap is ALL I do. Let me move your crap.”


    “Have Hariven; will haul (your crap).”

  3. Why am I imagining this thing is built by Kerbals? Just out of curiosity, are there any freight haulers built along the lines of the Venture Star from Avatar?

    • There are ships that are more along her school of design, but they’re not regular freighters, they’re relativistic freighters – or lighthugger luggers, as they’re called. And those often include things like on-board factories and so forth, because when your time of flight is measured in years, you might as well haul your industrial capacity along with you.

      (They’re kinda big.)

  4. Kerbals: I currently don’t have the joy of flinging J. Kerman around in dicey, duct tape, vehicles, but I follow what other folks do in K-space from time to time. The Hariven reminds me of a Cygnus-type container ship I once saw. It was essentially a steel box with a fat thruster on its keister-end, trundling from Ghod knows where to Ghod knows where. Unlike the flashier K-craft (which leave me cold and shrugging) that crappy vehicle had me all ‘yep, there she is!’.

    I got a crappy space ship fetish.

    Venture Star: that would be a nice hauler (too flashy for me, though).

    • Ah, so you belong to the “What a piece of junk!” school of aesthetics. 😀

      Not really judging. I like ships of all kinds as long as they are interesting. To be honest, one of the things I dislike most about the Honorverse is the sameness of all the ships. I understand that part of that’s the “physics” involved, but they could at least give them a better paint job considering that mass isn’t exactly a major concern.

      As for the Venture Star, I never thought of it as flashy. It seemed like a perfectly utilitarian design to me, but then again, we may have “flashy” at different values.

      • “Ah, so you belong to the “What a piece of junk!” school of aesthetics.”

        Yeah, I guess so, though mebbe the *’brutalist/functional’ school works better.

        Don’t need to be pretty if it runs right (defined, by me, as gettin’ you were you wanna be, in reasonable safely, in a reasonable amount of time [like my old Ford Focus]).

        *as assessed by Mr. Young

        • ‘Twas only jest, but yeah, the Functional School does sound more respectable. I’ve been in love with Homeworld’s design aesthetic for a while now. It helps that you can very easily render it in Lego.

          As they say, though, beauty is in the eye of the beholder, and it doesn’t have to sleek to be cool. 🙂

          • Last night, me and the ten year old were fartin’ around with his Legos. He, being shiny new, mind, body, and soul, jumps in and builds elaborate thingamabobs. Me, bein’ on the decrepit side (my mind’s eye has a cataract), I stick two bricks together and marvel at my genius.

            I went a little further and built a Hariven. I used gray, black, and brown bricks and pieces (with a splash of yellow and a sliver of white and dark green). Rather proudly, I showed the ten year old the Hariven. He was unimpressed.

            I told him, ‘Poop on you! This here is a Hariven! Respect it!’

            He gave me that look children reserve for adults with degraded minds.

            Later, I showed him a shot of the Drake…he said, ‘That’s a spaceship!’

            I think I’ll sell him to the Gypsies.

  5. Not that long ago, I spent quite some time running the numbers on fusion-pulse torch drives, and working out various performance figures and limitations. It was all quite informative and interesting. You haven’t given nearly enough information about the ship (eg. dry mass) or the engine (exhaust velocity ranges, reaction mass) for me to hazard a guess at its parameters, so it’ll be interesting to see what else you have for us…

    There’s a lot of steel mention in its design. Sounds pretty heavy. Also, metal shells plus charge particle radiation equals bremmstrahlung delight (and it makes for a poor neutron shield, which this sort of drive badly needs). Carbon is probably easier to come by, and much easier to push around.
    You don’t mention reaction mass, but with those performance figures you won’t be using pure fusion for peak acceleration. Presumably the drive expends additional deuterium for that purpose (though lithium might be a better choice).
    You’re using pure deuterium fusion, but that’s a terrible choice for spacecraft fuel, really. For flights much less than the halflife of tritium, D-T offers easier ignition, lower neutron flux and more charged particles to thrust against. D-He3 would be the fuel of choice, but if you want stable and conveniently mineable fuel p-Li6 or p-B11 would be a much better choice than pure deuterium.
    Delta-V reserves for even a fairly conservative fusion spacecraft design are pretty generous. You might not be tooling around at cruising speed for long, but it should be able to sustain a centigee for weeks (or even months if the drive is good enough) at a time with a 3 or 4:1 wet to dry mass ratio.

    • (on reflection, I am of course wrong that D-T offers a lower neutron flux or a higher proportion of charged reaction products than D-D, but it does offer a significantly lower x-ray output and a higher exhaust velocity)

    • Ah, but you’ve got to bear in mind the target market, and therefore the design paradigm. If this were higher up the scale of starships, it’d have all the fancy carbon-composite hulls, high-efficiency fuel blends, etc., etc., one could possibly desire.

      It’s steel, though, because it’s designed to be repaired – and in some cases, even built – by a monkey with a wrench, a backyard welding kit, and duct tape, not by professional yard dogs with all the nanowhatsits in the catalog.

      (Same reason the neutron protection is a slug of paraffin in the lower hull space rather than proper formed HICAP.)

      Likewise, it uses D pellets to power an old-style fusion pulse drive rather than D-He3 slush to power a new-style fusion torch because that drive needs much less maintenance, any backplanet schmuck can separate deuterium from water, and the calibration is rough enough that in a pinch, you can stuff just about anything that’ll fuse in there and it’ll mostly work for a while.

      (Basically, you want to picture the spacegoing equivalent of the beat-to-hell jalopy that’s been driven around the rainforest for forty years, being fixed with banana peels and duct tape and occasionally run on rough home-cooked rum when gas was short. It’s a shitbox, but it’s a shitbox that’s hard to kill by design.)

      • I wonder about the economics there. I Am Not An Astrogeologist, but I think that carbon is Quite Common in space, probably many orders of magnitude more common than metal. The actual difference in value might be difficult to quantify, given that most planetary systems have Quite A Lot of stuff floating around, but there may be all sorts of other things that want ferrous metals as feedstock or for components. Anyway, that aside… you could probably brew up a resin capable of holding air in (but probably not vacuum stable) out of ice and grit and sunlight.

        WIth regards to the drive: pulsed ICF is a pretty good drive technology. Potentially better in some ways than a continuous burn fusion engine, as once you’ve cracked the ignition problem you can build a pretty minimal reaction chamber than vastly reduces shielding and cooling requirements. This also makes it much easier to create a very high power pulsed ICF drive, of the sort that could make journeys across star systems in non-totally-unreasonable times. Its no beam-core antimatter, but neither is other kind of fusion drive.

        As for fuel: D-D might be easy to come by, but it is hard to ignite and kicks out a lot of x-rays as well as neutrons. Those x-rays need dense, heavy metals to shield them, and dense heavy metals exposed to high neutron flux turn pretty radioactive. So your D-D ship will likely end up more radioactive than a D-T ship, require heavier, more expensive shielding, more inconvenient disposal, more complex maintenance requirements and all that for something with lower exhaust velocity that requires a more complex and more powerful beam array to ignite (a beam array which, incidentally, could make for a more powerful weapon system if rejiggled correctly… local authorities may or may not care about this). For flight times of <1 year, D-T is pretty much better in every possible way.

        I’m also fairly certain that if you have an ICF system capable of burning D-D, you could feed it D-T by cranking the drive beam power levels right down and it would Just Work. Probably. It should also work for D-He3, too, as that also needs a much lower plasma temperature than D-D fusion.

        I still stand by my p-Li6/p-B11 suggestion though. Stable fuel with reasonable availability, much reduced shielding requirements making for a lighter and more easily maintainable drive with much less radioactive waste and no massive lasers or particle beams required. In an emergency, you can probably tweak your fusor to take D, T or He3, too, but you can’t make an ICF system take Li or B fuel.

        • You’re right on the details, there, but again, it’s the context.

          Materials availability-wise: yes, carbon is more abundant. On the other hand, iron is post-post-scarcity anywhere asteroids are mined, as the process of extracting the interesting and actually scarce metals generates gigatons of the damn stuff as a side product, to the point that in the ‘verse mining companies will basically give you the stuff for the cost of hauling it away.

          But that’s not why they use steel, although it being dirt cheap doesn’t hurt: they use steel ’cause it’s easy to work with compared to other reasonable structural materials. Aluminum requires special welding techniques. Don’t even ask about what a pita titanium is to work with. Even plain old carbon fiber – leaving aside spinning it in the first place – requires specialized skills and equipment to work with, never mind fancy carbon composites or anything with nanostructure. But cutting and welding a steel hull can be done by pretty much any minimally trained tech with equipment that even a lot of people on Earth-now have in the shed.

          And that’s very important, since the sort of people who fly this class of ship don’t have any kind of high-falutin’ engineering qualification. Hopefully, they have a base-level Master’s Certificate and Nuclear Engineering competence certification, and if you’re lucky, those weren’t actually issued to Captain Harbatkin by Space Liberia, then picked off his corpse after a bar brawl, cleaned, and resold.

          Likewise, the deuterium. That’s because anyone who can pass chemistry class can separate deuterium from water – and because the stuff is found everywhere there’s hydrogen, which is everywhere – it’s easy to handle, it doesn’t decay, and when you do D-D fusion, it’s a monopropellant.

          (The designers would probably have used protium if they could, but that’s too hard to build a cheap-ass drive to run on.)

          It’s about as easy to deal with as starship fuel gets, and can be obtained anywhere in space, even on some backwater rim colony or technically undeveloped world where the locals look at you funny if you ask them for isotopically pure lithium.

          Bear in mind, too, that this class of owner cares a lot more about running costs than final costs. Purified 6Li, say, costs a lot more than nigh-ubiquitous water, and that’s assuming that you can’t just drop your Cheap-Ass Separator ™ on the nearest ice asteroid.

          This, incidentally, also explains a lot about disposal, because the captain-owners (look at the list of likely examples again) mostly don’t care about disposal. The average Hariven gets run until it catoes, gets sold at scrap prices to Shady Bob’s Wreckyard for what Shady Bob loosely calls “reconditioning”, or dumped on some environmentally-uncaring garbage heap like Brak Tífel. If one makes it to a reputable ship-breaker that disposes of radioactives conscientiously and appropriately, it’s time to throw a damn parade.

          • If I were working metals in space and had a relaxed attitude to radiation I’d be using electron beams. They’re useful items to have for mining and for reasonably high thrust engines (that can run on almost whatever you can throw into the reaction chamber) so I’d expect them to be readily available in a range of colors and sizes.

            Lithium purification might not be quite as hard as you suggest; there’s a poor man’s enrichment process which uses vacuum distillation, a mechanism readily available to anyone in space with a decent power reactor and some time to spare. On earth, at least, it is helped by the generous Li-6 to Li-7 ratio in natural sources, though I don’t know if that generalise to the solar system or elsewhere. The remaining depleted lithium probably makes for a good coolant. Poorly enriched lithium might not be much good as a fusion fuel, but it makes for a good combined coolant and neutron shield for your drive coils, or a good reaction mass for dirty neutron producing fusion reactions (eg. D-D or D-T)

            when you do D-D fusion, it’s a monopropellant.

            It’ll be adequate for high-Isp, low-thust regimes (and by low thrust I mean centigees at best) but deuterium is a poor choice for heating via neutrons (and that’s where most of your fusion energy is going after all) so you’ll have serious problems reaching a thrust of ~0.5g, let alone sustaining it. Incidentally, don’t discount low-thrust, long-burn flight regimes. A few centigees of sustained thrust could get you from Earth to Jupiter in a month or two

            If you let me know the loaded mass of a typical loaded Hariven, I could run some numbers for you, if you like. (unless you’ve already done that yourself, of course!)

  6. I can see a market for after-market upgrade parts for Harivens, especially by owners that want something a bit better for their flying scrap heap (i.e. if I can make this next run, I can upgrade the shadow shield and torch, which gives me more delta-V, which means I can make the longer runs which means I can upgrade the sensors…).

    • And tying back into the “inconspicuous espionage vehicle” thread mentioned above: I imagine that superficially beat-up but internally-turbocharged Harivens do make for great spy-craft if you’re a higher-tech agent wanting to look like he’s “slumming it” — especially if you can afford the processing power to have a virtual rec-center you can plug your brain into to compensate for the lack of physical leg-room.

      Picture a convoy of inconspicuous Hariven traders trawling their way through a down-market system — except beneath that beat-up exterior, instead of the usual trader stock, they’re actually packed to the gills with high-tech surveillance and communications equipment and piloted by savant AIs fine-tuned for a very specific set of skills.

      The only question remaining, of course, is what they’d be listening for in such a “down-market” location of space in the first place…

      • I’m not sayin’ it doesn’t happen, any more than other fun tricks like packing her hold full of mini-missiles and naming her Sweet Transvestite, but I’ll go so far as to say that it’s a lot more difficult than it looks to get away with, ’cause it’s real hard to hide all those antennae and the thermal and EM signatures of a holdful of active surveillance equipment in a manner that doesn’t scream “I am using a shit-ton of signature-baffling materials in here”.

        (This difficulty is why I profiled the typical job of a recon destroyer not to be stealth or misdirection, in the manner of the old Soviet spy trawlers, but rather making your way across the system on such a trajectory that they can’t catch you doing what they know perfectly well you’re doing.)

        • I can also see some quiet justifications for a “better than average” ship with the right history and the right log book.

          “You’ve got a pretty capable PDC array there.”
          “Lot of our early runs went through the Sillvea Belt, and I got sick and tired of getting suited up every two cycles to weld patches on from micrometeorites.”
          “And the better torch?”
          “Spent the money from my first really big run after paying off the mortgage to get a more modern torch and shadow shield. Gave me quite a few more meters-per-second of delta-V. Faster runs and less time on the float means I make more money.”
          “Love the sensors, almost entirely milspec.”
          “Won those as a bar bet.”

  7. Like a dog with a bone, I can’t put the Hariven down. Been thinkin’ about a variant based on this…

    “Indeed, sometimes it’s made from eight standard shipping containers.”

    Seems to me, some backyard mechanic/finagler might get the idea to leave off the 30 meter long cargo box, then install dust shielding and clamps on top the habitat section instead. That way the owner/operator might mount three, or five, or eight shipping containers in place, based on the run, worrying less about filling a hold and more about gettin’ high value/low volume cargo. Haulin’ one shipping container of self-sealing stem bolts might net a being more than a 30 meter long box (silo) filled with quadrotriticale (depending on the target market).

     Alternately, the Hariven-variant might allow for a cage-like attachment on top, creating a secure space for vacuum-indifferent break bulk, or raw ore if the owner/operator were a quixotic asteroid prospector.

    Shorn of the hold’s bulk, and runnin’ cargo-less, the Hariven-variant might be a bit quicker as well, makin’ it a kind of cut-rate courier.

    And, not worrying about the steel box in the initial construction might free up some capital to begin with, allowing for more D-pellet storage.

    I keep this up, I might very well turn the Hariven respectable.

  8. Hariven names

    steel box with a pulse drive


    what the hell are you starin’ at?!

    a piece of ship

    cold, hard, dry

    hand to mouth

    cost of livin’

    first, best property

    my business


    crate ‘o goods

    make do

    makin’ do



    makin’ a buck

    nope, not gonna

    bare minimum

    low overhead

    spare and cramped

    take it easy


    mind your own damn business!

    odds & ends

    slow ‘n steady


    square peg

    weed in the garden

    rusty nail

    rim job

  9. As I say up-thread, my mind’s eye has a cataract, so, as I can, I look for artwork of vehicles similar to the Hariven. I haven’t had much success other than the shuttle external tank (If you close one eye, squint with other, and forget about the cylindrical shape, the external tank makes for a half-assed Hariven analog as both share (mostly) the same dimensions…a poor substitute).

    Been thinkin’ of getting a commissioned piece done. There’s a lot of decent artists out there, but each and every one wants to get paid (as each and every one should), and I ain’t wealthy. So before I commit to artwork: anyone got any Hariven analogs to direct me to?

      • Well, leavin’ aside the torch drive, the non-droplet radiators, and the airlock door that’s spun around 90 degrees 🙂 But, hey, there are lots of fascinating retrofits out there. (Although if you try and retrofit a torch drive onto a stock Hariven without significantly upgrading the shadow shield, you’re going to need a few pairs of lead BVDs.)

        That said – I call too pretty! She’s running in open space with naught but a Whipple shield! We need dents, scuffs, dings, scratches, micrometeoroid punctures, and all the other stigmata of a ship that works for a livin’ without any of that space magic or fancy self-healing nanowhatsits.

        • Yeah, it’s not a perfect interpretation (too pretty, too small [I think], oriented wrong, etc.), but, as I say: my mind’s eye has a cataract, so I take what I can get.

          • Hey, this is Munson. Young, you’re right, it’s too pretty, but that’s not all. It’s also missin’ detail.

            Take my Make Do: along with all the justified, honorable signs of wear and tear and work you mention, she also has all kinds of practical detail. Her attitude control thrusters are a good example. Make Do has eight big honkin’ *Hydrazine RC clusters, one mounted to each corner of the cargo box’s bow, the other four mounted just in front of the edge of the pulse drive radiation shield. You can’t miss ’em: big ass tank/pipe/nozzle assemblies welded and bolted directly to the box.

            The artist (Andy So’nSo) neglected to include that kinda detail.

            Make Do also has all manner of insulated cable mounted to its **exterior: power/control lines runnin’ from them RC clusters upfront, back to the cockpit, along with lines for the EM receivers, radar, comm laser, and radio bundle, all of which are affixed directly to the cargo box at various points.

            So, yeah, it’s too pretty and not strictly accurate (a Hariven with a fancy torch ain’t a Hariven, way I see it), but as it’s probably the only piece of art dedicated to the best kind of ship there is, I have to agree with Quirk: gotta take what you can get.

            *yeah, we use Hydrazine…old school

            **gotta minimize breaks in the box…function over form, always…and, with that in mind, there’s one thing the artist got absolutely right…far out in the Rim, where we Golgothan barbarians (‘mind your own damned business and keep your friggin’ hands to yourself…or else’) thrive, we don’t dress our mules in Sunday-go-to-meetin’ finery…in the Civillized innards ‘style’ is valued higher and differently, we get that…we got a different sensibility about the subject, is all

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  12. I mebbe need to explain the post above…

    Some time back, I contacted the Solcommander. I pointed out the Hariven as a rough and ready lil freighter that just begged to be rendered (cuz, after all this time, the Hariven is still my all-time favorite).

    As you all can see: the Solcommander was kind enough to put sumthin’ together. Here’s the text that accompanying the renders he sent me by email…

    Hey there Henry.
    Sorry for the late reply, I’ve been crazy busy lately but don’t worry I didn’t forget your request. I had a look over the info you have on the ship and made something based on it tho I took the liberty of adding some of my own edits/ideas.
    The container has about 33 meters, the crew part has 12 meters and the engine has 11.
    I made the container with it’s own set of landing legs, main engine and all directions thrusters so that the container can fly solo and land on asteroids/planets the way the SpaceX boosters do and then it can fly back out in space, accelerate and maneuver and meet up with the ship, this way the ship doesn’t need to stop to pick up containers, thus conserving fuel.

    The ship also has up on top a scaffolding where it keeps smaller containers with spare parts and whatever other things fit there. It has a magnetic clamping arm down below, for picking up non-standard sized containers or other unfinished/damaged ships that need transporting. And a bunch of sensors all over the place. On the side it has the docking area with an extendable ring. I also added engines to stop/slow the ship and several sets of small all-directions thrusters.

    Solcommander’s interpretation is fine work. Lovely. But it’s not a Hariven. No, the lil cartoon version Andiferous(sic) put together (the one I linked to up-thread) is far closer.

    Yeah, I’m an ungrateful bastid: Solcommander did me a solid (sumthin’ I greatly appreciate) but it’s just not ‘right’.

    And the search continues…

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