6 ms·

Really cool to think about it. I didn't think they'd just drop 2 tonnes worth of batteries like that.

m4rtink 3y ago
I recently saw in person a non-flight part of a Vega satellite dispenser - rather solid looking 80+ kg aluminum ring like shape, that during a normal flight profile burns up about 100 minutes after lunch via controlled re-entry of the upper stage. Apparently, very little of that is expected to come down, courtesy of the 8 km/s of kinetic energy it has turning into heat in a very short amount of time. I image it will be the same for the battery pallet, aided with parts being thin skinned & pressurized.
bagels 3y ago
Not much else you can do with them. They won't stay in that low orbit without boosts, and pose a danger if they stay on orbit.
- bigfatfrock 3y ago
  Is it prohibitively expensive to just boost them into the sun or elsewhere, while in low orbit?
  - JumpCrisscross 3y ago
    > prohibitively expensive to just boost them into the sun or elsewhere, while in low orbit? It’s easier to exit the Solar System than it is to boost mass into the Sun from any Earth orbit [1][2]. The atmosphere providing braking for “free” is a huge propellant saver. [1] https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_map.svg https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_ma... [2] https://space.stackexchange.com/questions/3612/calculating-solar-system-escape-and-and-sun-dive-delta-v-from-lower-earth-orbit https://space.stackexchange.com/questions/3612/calculating-s...
    - o11c 3y ago
      That's commonly cited, but actually a wrong implication of delta-v. It's expensive to get close to the Sun at low speeds (e.g. if you could land on it, or if you want a close orbit). It's trivial to slingshot around the moon and impact the Sun at high speed.
      - JumpCrisscross 3y ago
        > actually a wrong implication of delta-v Could you share a sample pair of trajectories that demonstrates this claim?
      - mnw21cam 3y ago
        The Earth's orbital velocity around the Sun is ~30km/s. You need to cancel almost all of that out in order to shift to a trajectory that intersects the Sun, and that trajectory still has you impacting the Sun at quite some speed. The Moon's orbital velocity around the Earth is ~1km/s. A slingshot manoeuvre around the Moon isn't going to help nearly enough here. One of the most efficient ways to get to the Sun is to leave Earth in the same direction it is going (and yes you can use a Moon slingshot to help here if you want) which will result in your rocket going further away from the Sun than the Earth. Once you're out in the region of the outer planets, you'll be travelling a lot slower and won't need to cancel out nearly as much velocity. Neptune's orbital velocity is ~5.5km/s, and if your rocket has an apohelion around there and a perihelion around Earth then you'll be travelling slower than that. However, it still takes a huge amount of delta-v to get out to the region of Neptune and then cancel out your velocity relative to the Sun. Compare that to the amount of delta-v required to de-orbit an object from low Earth orbit. The object's velocity around the Earth is going to be about 7.9km/s, but it only requires a delta-v of around 100m/s to put it into a nice predictable atmospheric entry. That's comparatively nothing.
      - JKCalhoun 3y ago
        Not so trivial though to slingshot around the Moon? (Though ISS is in orbit, I believe there is some ways still to climb from ISS to get to the Moon.)
      - perihelions 3y ago
  - deleted 3y ago
    [deleted]
  - lmm 3y ago
    Yes. LEO is "halfway to anywhere" but only halfway, boosting up to a high earth orbit requires significant amounts of fuel, getting all the way out of earth's gravity well takes more, and to get to the sun would take even more than boosting all the way out of the solar system. If they put them in an orbit "next to" the ISS then atmospheric drag would eventually carry them down until they burned up (even the ISS itself needs to be regularly boosted or it would eventually fall down) but that way it's unpredictable and uncontrolled (and there's always the risk of them hitting a satellite or something), a planned re-entry burnup is generally thought to be safer.
  - bagels 3y ago
    Yes. Dropping in to the atmosphere is safer and infinitely cheaper than any other choice but not sending things to orbit in the first place.
- thorum 3y ago
  Is it not possible (yet) to return them to the surface in a controlled manner via a SpaceX capsule of some kind? (Or just not seen as worth the expense?)
  - duskwuff 3y ago
    The only such capsules available are already being used to return astronauts. There isn't enough spare capacity for returning much else -- and certainly not 2.6 metric tons of batteries.
  - mandevil 3y ago
    The Space Shuttle was weird and unusual in that it was the only spacecraft ever capable of bringing significant payload back down to Earth. It cost a whole lot of payload up mass to get that capability (every flight had to carry the reentry protection for that huge payload bay, even if you didn't actually need it) and it was used on several occasions- things like Palapa and Westar (STS-51A), Solar Max, and all the SpaceLab missions- but on many other flights the payload bay came home ~empty and all that protection weight could have had better uses. All that comes home in current spacecraft (Dragon, CST, Soyuz, Shenzhou) is the small compartment with the people in it, and each of them even leaves the "orbital module"- all the fuel etc. behind to be burned up in the atmosphere. (Progress cargo flights burn up, but Cargo Dragon is actually recovered so some amount of cargo can be returned fully to Earth, but its mostly scientific stuff that is coming back in there right now as I understand it.)
    - KennyBlanken 3y ago
      That's because the Space Shuttle was designed to be a spy-agency space cargo van (with parts from nearly every congressional district to guarantee it would sail through congressional approval despite being hideously expensive and impractical.) Make everyone go "ooo, lookie at the science teacher doing experiments to see how [plant/animal] acts in space, everybody!" so they pay no attention to the spy satellite in the cargo bay (or the different spy satellite, or other equipment, being brought back.)
  - bagels 3y ago
- sdenton4 3y ago
  I would imagine that breaking them up instead of dropping as a single unit could be beneficial - higher surface to volume ratio, leading to more thorough burn up in the atmosphere.
  - JumpCrisscross 3y ago
    The trade-off is a less-predictable trajectory. (I don’t know the margin of error for this splashdown. Breaking it up might have been the safer move.)
    - eru 3y ago
      I guess it also depends on how small you break them down.
krallja 3y ago
“The uncontrolled disposal of the pallet, however, was not part of the original plan. It was made necessary by a disrupted spacewalking schedule following the failed launch of a Soyuz rocket in 2018, which forced NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin to make an emergency landing in the Kazakh steppe. This event led to a backlog in the disposal of such equipment. Normally, old batteries would be placed inside an HTV and jettisoned from the ISS to burn up on re-entry.” https://gizmodo.com/massive-iss-cargo-pallet-reentry-earth-march-2024-1851317508 https://gizmodo.com/massive-iss-cargo-pallet-reentry-earth-m...
- jauntywundrkind 3y ago
  Would that be different? Is there any benefit to burning up the batteries in a HTV vs letting them drop?
  - geerlingguy 3y ago
    Control - the HTV is automated to descend with a preset profile, so it would not just come down at random after a bunch of orbits.
  - dotancohen 3y ago
    The current tragedy has the batteries just minutes away from hitting London or Berlin. A controlled reentry would be much further from large population centres.
    - sokoloff 3y ago
      Is the current event a tragedy? It seems maybe a tragedy in the literary genre sense of the word more than in the disastrous event sense of the word.
      - dotancohen 3y ago
        That's what I get for typing on a phone with autocorrect. The word should have been "trajectory" though I concede that I may have spelled that incorrectly enough for the autocorrect to mistake the word.

I recently saw in person a non-flight part of a Vega satellite dispenser - rather solid looking 80+ kg aluminum ring like shape, that during a normal flight profile burns up about 100 minutes after lunch via controlled re-entry of the upper stage. Apparently, very little of that is expected to come down, courtesy of the 8 km/s of kinetic energy it has turning into heat in a very short amount of time. I image it will be the same for the battery pallet, aided with parts being thin skinned & pressurized.

bagels 3y ago

Not much else you can do with them. They won't stay in that low orbit without boosts, and pose a danger if they stay on orbit.

bigfatfrock 3y ago
Is it prohibitively expensive to just boost them into the sun or elsewhere, while in low orbit?
- JumpCrisscross 3y ago
  > prohibitively expensive to just boost them into the sun or elsewhere, while in low orbit? It’s easier to exit the Solar System than it is to boost mass into the Sun from any Earth orbit [1][2]. The atmosphere providing braking for “free” is a huge propellant saver. [1] https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_map.svg https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_ma... [2] https://space.stackexchange.com/questions/3612/calculating-solar-system-escape-and-and-sun-dive-delta-v-from-lower-earth-orbit https://space.stackexchange.com/questions/3612/calculating-s...
  - o11c 3y ago
    That's commonly cited, but actually a wrong implication of delta-v. It's expensive to get close to the Sun at low speeds (e.g. if you could land on it, or if you want a close orbit). It's trivial to slingshot around the moon and impact the Sun at high speed.
    - JumpCrisscross 3y ago
      > actually a wrong implication of delta-v Could you share a sample pair of trajectories that demonstrates this claim?
    - mnw21cam 3y ago
      The Earth's orbital velocity around the Sun is ~30km/s. You need to cancel almost all of that out in order to shift to a trajectory that intersects the Sun, and that trajectory still has you impacting the Sun at quite some speed. The Moon's orbital velocity around the Earth is ~1km/s. A slingshot manoeuvre around the Moon isn't going to help nearly enough here. One of the most efficient ways to get to the Sun is to leave Earth in the same direction it is going (and yes you can use a Moon slingshot to help here if you want) which will result in your rocket going further away from the Sun than the Earth. Once you're out in the region of the outer planets, you'll be travelling a lot slower and won't need to cancel out nearly as much velocity. Neptune's orbital velocity is ~5.5km/s, and if your rocket has an apohelion around there and a perihelion around Earth then you'll be travelling slower than that. However, it still takes a huge amount of delta-v to get out to the region of Neptune and then cancel out your velocity relative to the Sun. Compare that to the amount of delta-v required to de-orbit an object from low Earth orbit. The object's velocity around the Earth is going to be about 7.9km/s, but it only requires a delta-v of around 100m/s to put it into a nice predictable atmospheric entry. That's comparatively nothing.
    - JKCalhoun 3y ago
      Not so trivial though to slingshot around the Moon? (Though ISS is in orbit, I believe there is some ways still to climb from ISS to get to the Moon.)
    - perihelions 3y ago
- deleted 3y ago
  [deleted]
- lmm 3y ago
  Yes. LEO is "halfway to anywhere" but only halfway, boosting up to a high earth orbit requires significant amounts of fuel, getting all the way out of earth's gravity well takes more, and to get to the sun would take even more than boosting all the way out of the solar system. If they put them in an orbit "next to" the ISS then atmospheric drag would eventually carry them down until they burned up (even the ISS itself needs to be regularly boosted or it would eventually fall down) but that way it's unpredictable and uncontrolled (and there's always the risk of them hitting a satellite or something), a planned re-entry burnup is generally thought to be safer.
- bagels 3y ago
  Yes. Dropping in to the atmosphere is safer and infinitely cheaper than any other choice but not sending things to orbit in the first place.
thorum 3y ago
Is it not possible (yet) to return them to the surface in a controlled manner via a SpaceX capsule of some kind? (Or just not seen as worth the expense?)
- duskwuff 3y ago
  The only such capsules available are already being used to return astronauts. There isn't enough spare capacity for returning much else -- and certainly not 2.6 metric tons of batteries.
- mandevil 3y ago
  The Space Shuttle was weird and unusual in that it was the only spacecraft ever capable of bringing significant payload back down to Earth. It cost a whole lot of payload up mass to get that capability (every flight had to carry the reentry protection for that huge payload bay, even if you didn't actually need it) and it was used on several occasions- things like Palapa and Westar (STS-51A), Solar Max, and all the SpaceLab missions- but on many other flights the payload bay came home ~empty and all that protection weight could have had better uses. All that comes home in current spacecraft (Dragon, CST, Soyuz, Shenzhou) is the small compartment with the people in it, and each of them even leaves the "orbital module"- all the fuel etc. behind to be burned up in the atmosphere. (Progress cargo flights burn up, but Cargo Dragon is actually recovered so some amount of cargo can be returned fully to Earth, but its mostly scientific stuff that is coming back in there right now as I understand it.)
  - KennyBlanken 3y ago
    That's because the Space Shuttle was designed to be a spy-agency space cargo van (with parts from nearly every congressional district to guarantee it would sail through congressional approval despite being hideously expensive and impractical.) Make everyone go "ooo, lookie at the science teacher doing experiments to see how [plant/animal] acts in space, everybody!" so they pay no attention to the spy satellite in the cargo bay (or the different spy satellite, or other equipment, being brought back.)
- bagels 3y ago
sdenton4 3y ago
I would imagine that breaking them up instead of dropping as a single unit could be beneficial - higher surface to volume ratio, leading to more thorough burn up in the atmosphere.
- JumpCrisscross 3y ago
  The trade-off is a less-predictable trajectory. (I don’t know the margin of error for this splashdown. Breaking it up might have been the safer move.)
  - eru 3y ago
    I guess it also depends on how small you break them down.

krallja 3y ago

“The uncontrolled disposal of the pallet, however, was not part of the original plan. It was made necessary by a disrupted spacewalking schedule following the failed launch of a Soyuz rocket in 2018, which forced NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin to make an emergency landing in the Kazakh steppe. This event led to a backlog in the disposal of such equipment. Normally, old batteries would be placed inside an HTV and jettisoned from the ISS to burn up on re-entry.” https://gizmodo.com/massive-iss-cargo-pallet-reentry-earth-march-2024-1851317508 https://gizmodo.com/massive-iss-cargo-pallet-reentry-earth-m...

jauntywundrkind 3y ago
Would that be different? Is there any benefit to burning up the batteries in a HTV vs letting them drop?
- geerlingguy 3y ago
  Control - the HTV is automated to descend with a preset profile, so it would not just come down at random after a bunch of orbits.
- dotancohen 3y ago
  The current tragedy has the batteries just minutes away from hitting London or Berlin. A controlled reentry would be much further from large population centres.
  - sokoloff 3y ago
    Is the current event a tragedy? It seems maybe a tragedy in the literary genre sense of the word more than in the disastrous event sense of the word.
    - dotancohen 3y ago
      That's what I get for typing on a phone with autocorrect. The word should have been "trajectory" though I concede that I may have spelled that incorrectly enough for the autocorrect to mistake the word.