101955 Bennu is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and tied for the highest cumulative rating on the Palermo Technical Impact Hazard Scale. It has a cumulative 1-in-1,800 chance of impacting Earth between 2178 and 2290 with the greatest risk being on 24 September 2182. It is named after the Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth.

101955 Bennu has a mean diameter of 490 m (1,610 ft; 0.30 mi) and has been observed extensively with the Arecibo Observatory planetary radar and the Goldstone Deep Space Network. Bennu was the target of the OSIRIS-REx mission which is intended to return its samples to Earth in 2023 for further study. On 3 December 2018, the OSIRIS-REx spacecraft arrived at Bennu after a two-year journey. It orbited the asteroid and mapped out Bennu's surface in detail, seeking potential sample collection sites. Analysis of the orbits allowed calculation of Bennu's mass and its distribution.

On 18 June 2019, NASA announced that the OSIRIS-REx spacecraft had closed in and captured an image from a distance of 600 metres (2,000 ft) from Bennu's surface. In October 2020, OSIRIS-REx successfully touched down on the surface of Bennu, collected a sample using an extendable arm, secured the sample and prepared for a return trip to Earth. On 10 May 2021, OSIRIS-REx successfully completed its departure from the Bennu asteroid while still carrying the sample of the asteroid rubble.

Astrometric observations between 1999 and 2013 have demonstrated that 101955 Bennu is influenced by the Yarkovsky effect, causing the semimajor axis of its orbit to drift on average by 284±1.5 meters/year. Analysis of the gravitational and thermal effects has given a bulk density of ρ = 1190±13 kg/m3, which is only slightly denser than water. Therefore, the predicted macroporosity is 40±10%, suggesting the interior has a rubble pile structure or even hollows. The estimated mass is (7.329±0.009)×1010 kg.

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  • ZachWilsonGOAT [he/him]
    ·
    edit-2
    3 years ago

    ok, it gave me this

    NTFS signature is missing.
    Failed to mount '/dev/sda2': Invalid argument
    The device '/dev/sda2' doesn't seem to have a valid NTFS.
    Maybe the wrong device is used? Or the whole disk instead of a
    partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?

    this is how the disk and the partition show in the Ubuntu 'Disks' program., not sure if that helps or not. i don't know much but it does look odd.

    • PorkrollPosadist [he/him, they/them]
      ·
      edit-2
      3 years ago

      Fascinating. It looks like you're doing everything right, but that message isn't a great sign.

      I suppose we should review the facts. The computer boots the Ubuntu LiveUSB, so we can probably toss out the SecureBoot theory. If that wasn't enough, it is capable of detecting the disk and reading the partition table from it. Ubuntu is demonstrably capable of reading the disk, so this isn't the reason it isn't able to mount the filesystem.

      The ntfs-3g driver is present, so it isn't due to the lack of a driver. The driver is erroring out and saying it doesn't recognize the NTFS signature. This indicates that something is wrong. This is supported by the fact that Windows barely runs, though the fact that Windows runs at all is kind of surprising.

      As for the root cause, it could be a number of things. I would treat the disk itself with suspicion, but it could also be a power failure at a bad time, an extremely uncommon software bug, cosmic rays, who knows.

      I've never used it, but there is a tool called ntfsfix which might help. To quote the manual:

      ntfsfix is a utility that fixes some common NTFS problems. ntfsfix is NOT a Linux version of chkdsk. It only repairs some fundamental NTFS inconsistencies, resets the NTFS journal file and schedules an NTFS consistency check for the first boot into Windows.

      You may run ntfsfix on an NTFS volume if you think it was damaged by Windows or some other way and it cannot be mounted.

      I'd give sudo ntfsfix /dev/sda2 a shot, but be aware that this will make changes to the filesystem. I'm sure the tool errs on the side of caution, but from a data forensics best practices standpoint it's best to have a backup image before messing around with it. Anyway, the tool is probably present on the liveUSB already, since it is a part of the ntfs-3g project.

      After running it, try booting Windows again and see if it can complete the consistency check. Or try mounting the filesystem again.

      There's also the option of running chkdsk directly on Windows, but that seems like it would be quite a challenge under the circumstances. It could be done though if you have a second Windows computer which you can plug this hard drive into.

      • ZachWilsonGOAT [he/him]
        ·
        edit-2
        3 years ago

        Mounting volume... NTFS signature is missing.
        FAILED
        Attempting to correct errors... NTFS signature is missing.
        FAILED
        Failed to startup volume: Invalid argument
        NTFS signature is missing.
        Trying the alternate boot sector
        The alternate bootsector is usable
        Set sector count to 1953259519 instead of 1953488895
        Rewriting the bootsector
        The boot sector has been rewritten
        ntfs_mst_post_read_fixup_warn: magic: 0xaaaaaaad size: 1024 usa_ofs: 21846 usa_count: 21845: Invalid argument
        Record 0 has no FILE magic (0xaaaaaaad)
        Failed to load $MFT: Input/output error
        Volume is corrupt. You should run chkdsk.

        i'm guessing the last time windows crashed my broken SSD also corrupted my HD? nothing to be done other than trying a fresh install of another OS and hope it works, right?

        i'm actually kind of wondering if it's actually my hard drive that's bunk and not my SSD, but that'd be odd. as i mentioned earlier i can mount the ssd and check files. at the same time i don't think Windows wouldn't load because a secondary drive is corrupt. guess i'll unplug the hard drive later and report back what happens.

        thank you so much for your help thus far! if you could PM me with a paypal or something i'd love to buy you a coffee as a thanks for the time you put into this. i really do appreciate it a lot.

        • PorkrollPosadist [he/him, they/them]
          ·
          3 years ago

          i’m guessing the last time windows crashed my broken SSD also corrupted my HD?

          I hadn't thought about this at all, but if the OS is crashing regularly and it's messing around with additional disks, this is possible. Normally the main disk is going to be doing most of the work though and a secondary disk used for storing music/games/whatever will be remain mostly idle unless you try accessing things from it. It should be doing very little writing unless you're actually doing something with it at the moment. And still, journaled filesystems are a lot more resilient than shit like FAT and ext2 we used in the 90s which would shatter like glass. I think you would still have to be particularly unlucky for this to happen.

          at the same time i don’t think Windows wouldn’t load because a secondary drive is corrupt. guess i’ll unplug the hard drive later and report back what happens.

          Right. I won't say it's impossible, but it would be very strange. Unplugging the drive and giving it a shot couldn't do any harm though.

          if you could PM me with a paypal or something i’d love to buy you a coffee as a thanks for the time you put into this.

          No need. o7