17
$\begingroup$

In my story, some personal effects get jettisoned from a spacecraft airlock. Some time later (months to years), other characters discover one of these items drifting in space. It holds information on it, but I'm not sure what format to use. I'm sure the obvious answer is an SSD or some form of flash storage, but there are reasons in the story for the technology to be outdated.

I initially wanted to use a VHS tape, but I don't know if the tape would degrade in the cold vacuum of space and/or with direct exposure to the sun. I'm sure text on paper would get bleached, but what if it was a notebook or folder that remained closed? Would a floppy disk or CD-ROM have any issues, or are all forms of digital storage equally fine in this scenario? Is this a silly question? Thanks in advance!

Edit: To be as specific as possible, I'm looking for the most viable form(s) of data storage, in widespread public use pre-2010, that would survive approximately one year orbiting the Earth at about 200,000 km/125,000 mi.

$\endgroup$
13
  • 2
    $\begingroup$ Not a silly question. I also think you should consider whether the jettisonning itself wouldn't be damaging as well. $\endgroup$ Oct 19, 2023 at 21:41
  • 4
    $\begingroup$ How close to what sort of star and/or planet were the items jettisonned? I'm interested in the answer too, but suspect that the answer will differ considerably if the items are in orbit around/near Mercury compared to, Jupiter (less sunlight but its own magnetic/radiation fields) or out in the Kuiper belt. $\endgroup$ Oct 19, 2023 at 21:48
  • 2
    $\begingroup$ Diligent research is required before asking a question. This site is not a free-of-charge research service. The question must show what research has already been done, and what difficulties could not be resolved. For example, how come you are sure that text on paper would be bleached? That will obviously depend on the ink. I am quite sure that many kinds of pigment ink won't get bleached all that easily. For example, Mitsubishi Pencil Company Limited's Uni-ball Uni-pin fineliners are cheap and very popular, and they work on Moleskine paper! $\endgroup$
    – AlexP
    Oct 19, 2023 at 21:55
  • 1
    $\begingroup$ I thought the canonical way is a gold disk but I see that you want it to be personal effects, so the gold disk is unlikely. $\endgroup$ Oct 20, 2023 at 10:42
  • 1
    $\begingroup$ It might be unreasonable to believe that a data storage device of any kind would find itself on (e.g.) a space station and not have been designed to be there. It's like suggesting someone would visit the Antarctic while carrying their water in plastic bags slung over their shoulders. On the other hand, Russia jettisoned a flash drive into space. The article doesn't say how long it's expected to last, other than NASA's claim that it will likely fall to Earth in a few weeks. $\endgroup$
    – JBH
    Oct 20, 2023 at 17:09

7 Answers 7

24
$\begingroup$

Paper should survive

There is not enough debris in space to consistently do damage over a year to exposed surfaces, so I assume that books, letters and the like should retain integrity. So your discoverers would at least discern information from anything written in a book or letter, provided it was etched, regardless of ink state. Etching is caused normally while writing with a ball point pen, as the process of ink transfer involves pressure to spin the ball while the pen slides over the paper. While the paint might mot survive the exposure due to sublimation or other reasons, the etching is not undone as quickly. Any debris hits would just make holes or splats, making a bit of text lost or unreadable, yet the whole might provide enough context to restore the missing letters.

Inks have troubles, but a year is not too long for them to completely degrade

The issues might hit anything printed, as both typographical print and laser print makes bits of paint adhere to surfaces rather than get embedded in them, making bits of paint less resistant to heat/cold strain and charged particles as a general exposure. Laser paint (toner) tends to get peeled off the sheets even on Earth over several years, even if the media was protected most of the time, in space this should worsen to a possibility of blotched space appearing all over a laser-printed media. Not sure if that media would stop being legible after just a single year, but give it ten, and it'll get almost blank.

Jet printed media resists heat/cold better but it might sublimate off the exposed media into vacuum, if the components of a paint were volatile enough, however that paint would leave traces in the paper for the researchers to still be able to discern the writings after several years of exposure. So count jet prints as legible with special measures.

CDs would likely break apart, and get numerous read errors

Unless the CDFS format used in your universe allows for ECC everywhere, the data on an exposed CD-R/CD-RW might be counted as lost, however large parts of it could still be read in fragments (sectors) containing one to several dozen actual bit errors. This is due to the data layer of a CD-R/W being exposed to high-energy sunlight (UV and above) and charged particles which deteriorate the state of sensitive material used to store the data. Sunlight intensity is hard enough to penetrate plastics, and anyway data writing to a CD-R/W is done with a laser of visible light (early, DVDs IIRC have an UV laser, anyway too low energy to not get erased by exposure), so the sunlight could just write random data over what was on the CD-R/W.

CD-ROMs are made differently, the data is contained in bits of metal embedded in plastics instead of in a contiguous layer of something, so each individual bit has far greater chance of survival under the sunlight. Yet there is a debris problem, a CD-ROM hit by a piece of dust at cosmic speeds has a high chance to split in half, or produce a crack in plastics that would result in it breaking apart when spun up for reading. However, since you're speaking about personal data, CD-ROMs are out of scope, as a person is not able to produce CD-ROMs on their own. So, while a CD-ROM stored in the stuff might actually survive (with probability), its contents would not belong to a person whose stuff that originally was.

SSD and Flash would lose data quickly enough

In fact SSDs are best to not get exposed to sunlight even on Earth, with UV shielding and stuff, as data on an SSD is stored in pockets holding electric charge, and any possibility of excitation causes charge leaking, resulting in different charge level at read, thus different bit sets (hello TLC+QLC!), this damage would also make the SSD controller to fail by losing its operational data (there's a ton, not going into details). Flash NAND memory also stores charge in form of triggers' state, leaking that charge is also pretty expected from charged particles and ionizing photons.

HDD might also not survive, but the data is protected better

The 2010s HDDs used quite small magnetic domains as means to store data, and some older but still working drives even did not have extra Flash NAND onboard storage for controller data (instead it was read from tracks off the working range at drive startup), and controller ROM was usually wired. Also external hard drives are normally boxed in, offering additional protection to exposed electronics. A year in space would cause air in a HDD to leak away, but some precautions taken after the HDD is retrieved (and in case of an old enough device, its controller board replaced to increase chances of it starting up normally) could let your discoverers delve into the decently vast personal storage of downloaded memes and Temporary Internet Files.

The HDDs are built with a metallic case that actually gives the data layer excellent protection from hazards in the near space, up to and including charged particles. In case a HDD is hit by dust, a too small bit would not even dent the cover, a too big bit would blow a hole through the cover and probably several disk plates out of how many installed (say a 18-TB hard drive of current manufacture has 9 plates, an old 4-TB SAS server-grade drive had two or four depending on the manufacturer, 2.5" HDDs usually have one, and should they have a IBM-2311 or similar device for their PC among their belongings (plate wise), it might only leave a dent worth several kilobytes even not preventing the device from working normally. That is, the older is the HDD, the easier it would be to get the data off it after space exposure, provided they are able to get spare parts for it. But even an average HDD of 2010s should remain perfectly readable in a clean room with tools, with about 99% of data being intact, even after several actual debris collisions. If it was boxed, and the box isn't penetrated, there is a decent chance that it'll just start up normally after being exposed to atmosphere for a day, to fill the insides through a breather hole.

Flexible media would suffer down to unreadability

The reason is that flexible media is made of polymers which are prone to deterioration under sunlight exposure, the stronger the harder. The good thing for tapes is that they are folded over a spindle at least hundredfold, so should the tape in question be retrieved quickly enough, and be initially rewound to start, the inner (close to tape end) parts of the tape might retain integrity. Still, the tape in itself would be unusable by an ordinary person, and would require special tools to be read. The good thing is that VHS tapes are analog signal, so any bit rot involved would not destroy the data.

Flexible disks aka floppies would likely suffer the same fate as the exposed or close-to-exposed areas of tape, aka crumple up destroying data stored on them. The 3.5" floppy is actually boxed, alowing it to get exposed for longer while retaining usability (reading should anyway be done raw, but floppies have large magnetic domains compared to HDDs so a lot harder to lose data to exposure, if not for the underlying media), yet they hold too small amount of data to be usable. And the 1990s floppies were not enduring enough read/write cycles to bother with them here (80s were a LOT better, I have one 720-kb floppy that's still readable, yet nowhere to read XDDD), maybe your world suffered the same. So, count tapes as damaged and unreadable without tools, floppies damaged or destroyed, depending on whether they are hardcover or not (3.5" are hardcover, 5.25" and 8" were not).

Summary

So, your best bet of recovering information from a personal media starts with books or written paper, followed by jet printed paper, followed by an external HDD, followed by a VHS tape, followed by a hardcover floppy disk. The biggest storage would be the HDD, followed by a VHS tape (with restrictions), followed by a written notebook, followed by a hardcover floppy (a notebook can hold a lot of more useful data than a floppy), followed by sheets of printed paper. Everything else you should consider being unreadable either completely or without very special tools, with a serious exception being HDD, that one depends on technology used - it might fall into both categories, depending on what happened to it over the year in space.

$\endgroup$
5
  • 1
    $\begingroup$ This is a great answer. To add to it: the OP can use any device he/she wants so long as the goods were jettisoned "in a standard XM-25 cargo container, which are designed to be shielded from radiation and heat so they can be stored temporarily in space during loading/unloading procedures." Bring some tinfoil-thin shielding to bear in the story and any technology can be rationalized for a year. $\endgroup$
    – JBH
    Oct 20, 2023 at 16:58
  • $\begingroup$ Great answer - you seem very knowledgeable, so I'd love to know what you think of engraved plates of metal or stone. They would presumably survive very well, but suffer from lack of information density? How about very small engravings? I don't need huge detail - and I realize it's somewhat off topic - so fair enough to tell me to write my own question, I guess ;) $\endgroup$
    – bytepusher
    Oct 21, 2023 at 16:04
  • 1
    $\begingroup$ @bytepusher those plates should be more durable versions of paper sheets with etched writings, with less erosion caused by light exposure and comparable chance of resisting micro-collisions (molecules), but greater chance of getting split apart with a macro-collision with a piece of dust. Depending on where such a plate is left in space, these might survive millions of years together with information, if not being hit by something relativey heavy. Not sure though if the metadata on the plate's engravings, as in, how to read that QR code, would survive for this long. $\endgroup$
    – Vesper
    Oct 22, 2023 at 5:22
  • $\begingroup$ good point about the collision: funnily enough, paper might survive this better! ISTR Voyager had plates in it... $\endgroup$
    – bytepusher
    Oct 22, 2023 at 10:43
  • $\begingroup$ As for flash memory--note that the long ago ancestor of modern flash was designed to erase by UV light. The chips had a window on them, uncover it and put it under a UV lamp and it would erase. The erase system has gotten a lot better and the durability a lot better (the originals were severely cycle-limited) but I would be surprised if it wasn't still vulnerable. $\endgroup$ Oct 22, 2023 at 16:51
6
$\begingroup$

The problem of space is not vacuum, but all the rest:

  • magnetic fields: these would damage any storage medium based on magnetism, like a VHS tape
  • charged particles: these would damage solid state memories, magnetic storage, film
  • (dust) particles: these would damage the surfaces of anything exposed to them, so writings, carvings etc. Think of sandblasting a surface
  • radiation: it would break down complex molecules, affecting inks, colors, plastic and so on
  • thermal cycles: close enough to a star, anything going from dark to light would go from few K to several 100s K, resulting in mechanical damages

The overall effect depends on the conditions of the exposure, in terms of time and energy.

$\endgroup$
3
  • $\begingroup$ How many windows of the ISS have needed replacing after two decades in space? $\endgroup$
    – AlexP
    Oct 20, 2023 at 8:13
  • 1
    $\begingroup$ "A few K" is a high overestimation, as it takes quite a lot to cool down an object that deep with radiation only. Perhaps "100 K" would be a better estimation for a freely floating object in space, and should it rotate faster than 1/minute, even cooling to 250K would prove difficult. "Jettisoned out of an airlock" might also mean that there was some atmosphere in the airlock when it got open, this causes all sorts of rotation to whatever floats outside. $\endgroup$
    – Vesper
    Oct 20, 2023 at 8:35
  • 1
    $\begingroup$ I like this answer because there's a difference between what will happen to something that wasn't designed to float free in space and something that is designed to do so. Comparing (e.g.) a terrestrial thumb drive to the ISS is silly. The ISS was designed to be in space, the thumb drive wasn't. $\endgroup$
    – JBH
    Oct 20, 2023 at 17:00
5
$\begingroup$

My vote would be for something that's somehow ended up being retro-futuristic: minidiscs.

A memorex minidisc with transparent casing

(image credit Evan-Amos via Wikimedia)

The MD Data format has been about since the '90s, and in its 2004-era form it could store 1GB of data. It has definitely been widely available, and though perhaps it was never that popular in the real world (and got discontinued in ~2012), we haven't had much crewed spaceflight beyond LEO for a few decades either so I think your fictional setting can stretch to it.

Minidiscs are a magneto-optical storage medium. Amongst other things, they require local heating (generally provided via a laser) and a strong local magnetic field in order to write data to them, which means they're much more robust to ambient non-ionising radiation and magnetic fields than purely magnetic or optical re-writeable medium. They have a plastic casing around the disc that can protect against a certain amount of environmental stress such as UV and some kinds of impact.

The major threat would seem to be micrometeorite damage, and that's hard to quantify as you've not given us much information about the orbit the objects would be in. 200000km is halfway to the moon, but that's an odd place to have a spacecraft in a circular orbit. A Hohmann transfer orbit between the Earth and the Moon would likely have a periapse in low-orbit around the world the spacecraft was departing from, and that low orbit is likely to have a reasonable amount of human-made debris. Further out, impacts are likely to be much rarer.

The JWST's mirror, all the way out at Earth-Sun L2 was expected to get struck about once a month, but the mirror segments do have a total area of >22m2... more than 4500x that of a minidisc seen face on, so a free-floating disc in space might reasonably not be hit at all in a year. LEO is a much dirtier place though.

Average cross sectional flux vs area chart, using ORDEM2000 data

This chart was taken from Sensitivity analysis of spacecraft in micrometeoroids and orbital debris environment based on panel method, and was derived from the ORDEM2000 dataset. There are newer datasets, but the ORDEM2000 set is fairly pessimistic and makes for a good worst-case, so I'll use it here. This assumes ~1000 strikes per square metre per year of 10μm debris. Now, if your disc had a large side facing the direction of travel for its whole orbit, that's a risk of 5 hypervelocity dust impacts per year. However:

  • That's a worst case scenario, and difficult to engineer... it would need to be entirely in LEO, and spinning at precisely one revolution per orbit in order to maintain the face-on orientation.
  • ORDEM2000 is fairly pessimistic, and other models like SDEEM2015 predict a 10-fold lower incidence of fine dust, enough to let your disc escape unscathed.
  • You probably wouldn't store minidiscs loose in your pocket.. A tough storage case for the disc will actually do a pretty good job of protecting against fine dust impacts... we're not talking about sand-grain sized things here, and objects larger than dust might not actually hit during that year in space.
  • There are areas of the casing that can be struck without risk to the disc inside.
  • It is possible to still read some of the disc even in the event of a certain amount of damage.
  • If it were edge-on to its orbit, it might reasonably not be struck at all.

So there you have it. Whilst not necessarily as long-term or easy to read as paper, minidiscs might well work OK for your needs, and have a significant storage capacity and existing technology base to handle them.


Also, honorable mention: M-Disc, a write-once DVD/blu-ray storage system that came out in ~2010. It is chemically and thermally very stable, and assuming it avoided too much physical damage it might well survive OK. Whilst it came out a bit late for your timescale, the technology to read it was very readily available, and your setting is already deviating from the real world so it isn't too big of a stretch.

$\endgroup$
1
  • 2
    $\begingroup$ Thinking about this, it's a perfect tech to retain data while exposed to space environment. Strong magnetic fields are uncommon away from celestial bodies, and should the MO-disk for systems used in their world be initially designed to have a metallic case, it would be protected well enough from charged particles and targeted radiation. The only thing that would break this disk, apart from getting hit, would be general overheat beyond Tc of whatever they used as storage media. (Hello HAMR, BTW should they also have a HAMR-based HDD, betcha data on it would also be safe enough) $\endgroup$
    – Vesper
    Oct 20, 2023 at 13:16
2
$\begingroup$

Clay tablets

This quite far pre-2010, pre-2010BCE even. It seems unlikely that a modern person would be in possession of clay tablets, but perhaps they are an archeologist or Luddite. Maybe they just had some engraved periodic table tchotchke on their space station desk.

enter image description here

$\endgroup$
0
$\begingroup$

Digital Magnetic Tape

Before modern computers, early spacecraft use magnetic tape for all their data storage needs. Early Mars lander missions (Viking 1 and Viking 2) are good examples.

The prime examples are the two Voyager Spacecraft. They still work and have been using 8-track digital magnetic tape since 1977. Granted, they are rather far away from the sun, but it's still insane to think that somewhere in deep space a tape-based computing system is still operating and has been doing so continuously for almost half a century.

Here is an image of the tape deck in the Voyager Spacecraft and you can read more about this here, on space.se

Voyager Tape deck prototype

Because of this, I think your best bet for slightly retro media would be a tape of some sort. There are lots of form-factors to choose from, and provided the tape isn't directly exposed to the sun but has some sort of case, I think even consumer-grade tape cassettes (audio, VHS) would be fine for at least a year.

$\endgroup$
2
  • 2
    $\begingroup$ Well, a built for space magnetic tape drive is designed to sustained flux and stuff, at least it should be sealed within a metallic case. Here we have a random civilian that had some of his stuff jettisoned off a space ship, I really doubt there could be one of these in operation. And exposed, tape goes as tape goes, deteriorating under sunlight. $\endgroup$
    – Vesper
    Oct 20, 2023 at 13:11
  • $\begingroup$ @Vesper Eh, in a setting/scenario where a regular person can have their stuff end up in space and that regular stuff includes a VHS tape, I don't think it's unreasonable that the individual would've splurged for the $4 more "space grade" VHS case that's made of metal. That aside, even a paper sleeve could provide adequate shielding. $\endgroup$
    – Dragongeek
    Oct 20, 2023 at 14:42
0
$\begingroup$

You want a personal effect that will survive.

Various answers have addressed the vulnerability of pretty much anything in common use. However, I can think of one item in modern use that I would expect the information to be retrievable from: a diary. Pen on paper in a notebook with a closure. It's closed so virtually all the abuse will be taken by the cover and the edges of the paper (and people usually don't write to the very edge), the actual written area is decently protected. It doesn't matter if the ink came off, a pen will etch the paper anyway.

$\endgroup$
-1
$\begingroup$

Astronauts were constantly being hit by micro-meteoroids on their moon trip which was just a few days each way. They're smaller than a grain of sand, but travel at an average of 22,500mph and would be constantly impacting.

So unshielded I doubt any conventional data storage will be much good after a year.

$\endgroup$
14
  • $\begingroup$ As far as I know no astronaut has ever been hit by anything, let alone "constantly". The ISS has been up for a long time. How many observable micrometeoroid hits has it experienced per square meter per day? $\endgroup$
    – AlexP
    Oct 20, 2023 at 8:10
  • $\begingroup$ @AlexP makes you wonder why they bother with the Wipple shields (ISS has this shield BTW). I watched a doco a long time ago where they deduced the astronauts were being hit and upon microscopic examination of the helmets found that they had indeed been hit. But look at the link in my answer it has lots of info. $\endgroup$
    – Kilisi
    Oct 20, 2023 at 8:17
  • $\begingroup$ Oh, yes, but those were not "smaller than a grain of sand", which implies some sort of small but still visible size. Those were really microscopic. As a quick and dirty calculation: Earth, with an area of 500 million square kilometers, receives about 5 thousand to 20 thousand (depending of whom you ask) tonnes of space dust per year, or about 0.01 milligrams to 0.04 milligrams of space dust per year per square meter. $\endgroup$
    – AlexP
    Oct 20, 2023 at 8:25
  • 1
    $\begingroup$ The point is that it is less than a milligram per year per square meter, even if we accept 100,000 tonnes. And the question is about one small device surviving one year. As a practical example, cubesats are launched routinely with no shielding to speak of, and operate just fine for significant lengths of time. Yes, you need shielding for large objects which are intended to stay up there for decades. $\endgroup$
    – AlexP
    Oct 20, 2023 at 8:28
  • 1
    $\begingroup$ @Kilisi: (If you are interested.) Those flashes of light are formally known as cosmic-ray visual phenomena. While we don't know with absolute certitude what produces them, the leading hypothesis is that they are caused by high-energy cosmic rays, either by emitting Cherenkov radiaton while crossing the transparent media of the eye, or by directly crashing in a neuron. Nothing to do with micrometeoroids. $\endgroup$
    – AlexP
    Oct 20, 2023 at 14:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .