5 ms·

E.Deorbit (2016)

23 points by acqq 8y ago

acqq 8y ago
"The mission is being prepared for approval during the next ESA Council at Ministerial level in late 2016" Anybody knows what happened then? What's the current status?
- wlkr 8y ago
  A set of slides from a presentation given by Luisa Innocenti, head of the Clean Space program at ESA, seems to indicate ongoing testing and a 2024 launch date. I couldn't find anything more concrete, unfortunately. http://www.jsforum.or.jp/stableuse/pdf/26%20Innocenti_eDeorbit_CleanSpace.pdf http://www.jsforum.or.jp/stableuse/pdf/26%20Innocenti_eDeorb...
  - acqq 8y ago
    Thanks, very good presentation! There's also a link to the "cleanspace" blog there at the end: http://blogs.esa.int/cleanspace/ http://blogs.esa.int/cleanspace/ Last post July 6, 2018, the project lives. Then from there, "The Clean Space Industrial Days 2018" event https://indico.esa.int/event/234/ https://indico.esa.int/event/234/ will happen: "23-25 October 2018 ESTEC"
AllegedAlec 8y ago
Using nets or arms seems wasteful to me, to be honest; you'd need to bring a new satellite up there for every piece of debris you want to get rid of. Wouldn't it be a lot more convenient to use something like laser ablation to slow down the debris and make it burn up in the atmosphere on its own?
- msadowski 8y ago
  I don't know the process of laser ablation. How would you use it in the context of this mission?
  - AllegedAlec 8y ago
    With laser ablation you fire a high-wattage laser as something to turn a very small surface layer to plasma. The expanding plasma cloud imparts an impulse onto the surface it is ablating, which can be used to slow down debris. https://en.wikipedia.org/wiki/Laser_propulsion#Ablative_laser_propulsion https://en.wikipedia.org/wiki/Laser_propulsion#Ablative_lase...
- garmaine 8y ago
  Laser ablation would create debris, wouldn’t it?
  - AllegedAlec 8y ago
    Technically, yes. You would cause some plasma to be formed, but I don't think it would in any way worsen the Kessler Syndrome situation.
msadowski 8y ago
Surprised to see this posted here! As a student I had a chance to take part in e-deorbit symposium in 2014. Back then they were considering 3 methods for capturing satellites: a net, robotic arm and a harpoon of sorts. What struck me the most from this conference is realizing how big of an issue space junk can be. From back then I remember the was no rules on disposing of satellites, the owning body could decide for a nice approach and use the fuel to put the satellite in a higher orbit, or slow it down so that it burns in Earth atmosphere. Or they could not give a shit and use the remaining fuel for operations, maximizing the profit.
ur-whale 8y ago
Are we saying that in the last 70 years or so, we managed to litter space so bad that this is actually a problem? Help me understand here: aren't we talking about a volume of space with a radial cross section significantly larger than the surface of the earth? I find it hard to believe we've launched so many things that collisions have become likely. Any actual data out there on the number of objects in orbit and the likelihood of collision? What am I missing?
- proaralyst 8y ago
  The problem is that if a collision happens it produces a lot of debris on unpredictable orbits. This process can run away and lead to orbital denial: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
- DanBC 8y ago
  The best source is NASA. https://orbitaldebris.jsc.nasa.gov/ https://orbitaldebris.jsc.nasa.gov/ The faq says: > More than 21,000 orbital debris larger than 10 cm are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million. Don't forget that these tiny fragments can cause significant damage.
- acqq 8y ago
  You miss that the kinetic energy is proportional to the square of the speed. https://www.quora.com/Which-one-makes-a-bullet-dangerous-its-kinetic-energy-or-its-momentum https://www.quora.com/Which-one-makes-a-bullet-dangerous-its... The speeds at which even the smallest debris hit other satellites are immense, compared to what we are used to in our surroundings. International Space Station moves at the speed of 17 thousand (!) miles per hour. Even the small pieces of something else moving at the different speed or direction will be extremely destructive, see again the explanation about how the bullets "work." Then consider the number of the pieces there and the fact that their movements are "unstable" (as in not keeping the trajectories that are always at the same distance from the Earth). Only once you understand all that read about: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
deleted 8y ago
[deleted]
Zarathust 8y ago
China showed a few years ago that blasting satellites with missiles is neither subtle or sustainable. This kind of thing could be weaponized much more efficiently
bumholio 8y ago
Once the proof of concept is demonstrated, an interesting development is to use a robotic arm to disassemble the junk and grind it into fine dust that can be used as propellant for an electrostatic engine: https://arxiv.org/abs/1511.07246 https://arxiv.org/abs/1511.07246 This way, a single mission can hop from orbit to orbit bringing down hundreds of targets instead of a sole suicidal mission. Another way for serial junk cleanup is to have a number of electrodinamic tethers and attach one on each target after de-tumbling. Even a few hundred meters of conductor materials (carbon fibre) would drastically reduce time in orbit.
- acqq 8y ago
  “This paper has been withdrawn by the author due to a crucial sign error in figure 1”
  - bumholio 8y ago
    Sorry, here's a cached copy: http://erewhon.superkuh.com/library/Space/Spacecraft/Debris%20Engine_%20A%20Potential%20Thruster%20for%20Space%20Debris%20Removal_%20Lei%20Lan_%20Jingyang%20Li_%20Hexi%20Baoyin_%20arxiv151107246.pdf http://erewhon.superkuh.com/library/Space/Spacecraft/Debris%... Regardless of any redaction errors, the basic idea is sound. While the particle engine is not able to produce the large impulse of ion drives (low specific ionization), it turns out the optimal impulse for such an application is in the 100-200 range. Any higher and the thrust drops too much prolonging the mission duration, for a given amount of electric power available. For this application the opposite is true: you want maximize thrust and throw away the full mass of the previous target before reaching the next one to be consumed.
    - acqq 8y ago
      “Regardless of any redaction errors, the basic idea is sound.” As far as I know the basic physics, the whole energy for the movement would still NOT come from the crushed satellite pieces but from some energy source in the satellite destroyer.

E.Deorbit (2016)

23 points by acqq 8y ago

acqq 8y ago

"The mission is being prepared for approval during the next ESA Council at Ministerial level in late 2016" Anybody knows what happened then? What's the current status?

wlkr 8y ago
A set of slides from a presentation given by Luisa Innocenti, head of the Clean Space program at ESA, seems to indicate ongoing testing and a 2024 launch date. I couldn't find anything more concrete, unfortunately. http://www.jsforum.or.jp/stableuse/pdf/26%20Innocenti_eDeorbit_CleanSpace.pdf http://www.jsforum.or.jp/stableuse/pdf/26%20Innocenti_eDeorb...
- acqq 8y ago
  Thanks, very good presentation! There's also a link to the "cleanspace" blog there at the end: http://blogs.esa.int/cleanspace/ http://blogs.esa.int/cleanspace/ Last post July 6, 2018, the project lives. Then from there, "The Clean Space Industrial Days 2018" event https://indico.esa.int/event/234/ https://indico.esa.int/event/234/ will happen: "23-25 October 2018 ESTEC"

AllegedAlec 8y ago

Using nets or arms seems wasteful to me, to be honest; you'd need to bring a new satellite up there for every piece of debris you want to get rid of. Wouldn't it be a lot more convenient to use something like laser ablation to slow down the debris and make it burn up in the atmosphere on its own?

msadowski 8y ago
I don't know the process of laser ablation. How would you use it in the context of this mission?
- AllegedAlec 8y ago
  With laser ablation you fire a high-wattage laser as something to turn a very small surface layer to plasma. The expanding plasma cloud imparts an impulse onto the surface it is ablating, which can be used to slow down debris. https://en.wikipedia.org/wiki/Laser_propulsion#Ablative_laser_propulsion https://en.wikipedia.org/wiki/Laser_propulsion#Ablative_lase...
garmaine 8y ago
Laser ablation would create debris, wouldn’t it?
- AllegedAlec 8y ago
  Technically, yes. You would cause some plasma to be formed, but I don't think it would in any way worsen the Kessler Syndrome situation.

msadowski 8y ago

Surprised to see this posted here! As a student I had a chance to take part in e-deorbit symposium in 2014. Back then they were considering 3 methods for capturing satellites: a net, robotic arm and a harpoon of sorts. What struck me the most from this conference is realizing how big of an issue space junk can be. From back then I remember the was no rules on disposing of satellites, the owning body could decide for a nice approach and use the fuel to put the satellite in a higher orbit, or slow it down so that it burns in Earth atmosphere. Or they could not give a shit and use the remaining fuel for operations, maximizing the profit.

ur-whale 8y ago

Are we saying that in the last 70 years or so, we managed to litter space so bad that this is actually a problem? Help me understand here: aren't we talking about a volume of space with a radial cross section significantly larger than the surface of the earth? I find it hard to believe we've launched so many things that collisions have become likely. Any actual data out there on the number of objects in orbit and the likelihood of collision? What am I missing?

proaralyst 8y ago
The problem is that if a collision happens it produces a lot of debris on unpredictable orbits. This process can run away and lead to orbital denial: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
DanBC 8y ago
The best source is NASA. https://orbitaldebris.jsc.nasa.gov/ https://orbitaldebris.jsc.nasa.gov/ The faq says: > More than 21,000 orbital debris larger than 10 cm are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million. Don't forget that these tiny fragments can cause significant damage.
acqq 8y ago
You miss that the kinetic energy is proportional to the square of the speed. https://www.quora.com/Which-one-makes-a-bullet-dangerous-its-kinetic-energy-or-its-momentum https://www.quora.com/Which-one-makes-a-bullet-dangerous-its... The speeds at which even the smallest debris hit other satellites are immense, compared to what we are used to in our surroundings. International Space Station moves at the speed of 17 thousand (!) miles per hour. Even the small pieces of something else moving at the different speed or direction will be extremely destructive, see again the explanation about how the bullets "work." Then consider the number of the pieces there and the fact that their movements are "unstable" (as in not keeping the trajectories that are always at the same distance from the Earth). Only once you understand all that read about: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome

deleted 8y ago

[deleted]

Zarathust 8y ago

China showed a few years ago that blasting satellites with missiles is neither subtle or sustainable. This kind of thing could be weaponized much more efficiently

bumholio 8y ago

Once the proof of concept is demonstrated, an interesting development is to use a robotic arm to disassemble the junk and grind it into fine dust that can be used as propellant for an electrostatic engine: https://arxiv.org/abs/1511.07246 https://arxiv.org/abs/1511.07246 This way, a single mission can hop from orbit to orbit bringing down hundreds of targets instead of a sole suicidal mission. Another way for serial junk cleanup is to have a number of electrodinamic tethers and attach one on each target after de-tumbling. Even a few hundred meters of conductor materials (carbon fibre) would drastically reduce time in orbit.

acqq 8y ago
“This paper has been withdrawn by the author due to a crucial sign error in figure 1”
- bumholio 8y ago
  Sorry, here's a cached copy: http://erewhon.superkuh.com/library/Space/Spacecraft/Debris%20Engine_%20A%20Potential%20Thruster%20for%20Space%20Debris%20Removal_%20Lei%20Lan_%20Jingyang%20Li_%20Hexi%20Baoyin_%20arxiv151107246.pdf http://erewhon.superkuh.com/library/Space/Spacecraft/Debris%... Regardless of any redaction errors, the basic idea is sound. While the particle engine is not able to produce the large impulse of ion drives (low specific ionization), it turns out the optimal impulse for such an application is in the 100-200 range. Any higher and the thrust drops too much prolonging the mission duration, for a given amount of electric power available. For this application the opposite is true: you want maximize thrust and throw away the full mass of the previous target before reaching the next one to be consumed.
  - acqq 8y ago
    “Regardless of any redaction errors, the basic idea is sound.” As far as I know the basic physics, the whole energy for the movement would still NOT come from the crushed satellite pieces but from some energy source in the satellite destroyer.