I’d be curious to see the actual design. How much existing aluminum are they replacing with wood? Assuming the wood is purely structural, doesn’t that leave solar panels and internal propulsion/electronics as is which happen to make up the most of a satellite’s volume?
We get showered by meteors all the time, I don't see how satellites create unique pollution. Or do artificial satellites reenter earth in larger magnitudes than meteors?
I'm with you it seems a little silly but looking into the question:
NASA https://science.nasa.gov/solar-system/meteors-meteorites/ gives the figure 44,000 kg of material falls to the Earth each day and that "Almost all" is vaporized in the atmosphere. A satellite can range from micro (~100 kg) to intermediate (~3000 kg) to extra heavy (>7000 kg). For reference Starlink started ~250 kg and the v2 are ~1250 kg. On average there should be ~10 deorbits per day at the current point, so safe to say at least an additional 25% over normal already.
The confusion that's left is how much of the material that naturally falls to the earth each day is also consider "polluting" and whether tons of such material is noteworthy pollution to be concerned about in spaceflight (for comparison global CO2 emissions are ~36,820,000,000,000 kg per year and a liter different in rocket fuel usage probably a lot larger pollution difference).
What does this have to do with the pollution being referred to in the article:
> All the satellites which re-enter the Earth’s atmosphere burn and create tiny alumina particles, which will float in the upper atmosphere for many years,” Takao Doi, a Japanese astronaut and aerospace engineer with Kyoto University, warned recently. “Eventually, it will affect the environment of the Earth.”
Shards or no shards, if a satellite weighs 1,000 kg then that's a maximum of 1,000 kg of aluminum particles that can burn up in the atmosphere - regardless how they do it.
> Japan to launch first wooden satellite to combat space pollution
Is it April 1st already ? They use wood becsuse it is "renewable" ? Or is it because burns better than other materials ?
Off Topic Question: Doesn't Space pollution causes problem when we launch spacecraft with the risk of colliding with those debris?
Pollution free satellites = good
Forcing everyone to use wooden satellites = bad
Hopefully the policy makers will get it now...
Edit: spelling
Looking forward to the Matthias Wandel build video...
I like the idea that they care, but cellulose at 10,000km/h is just as deadly as steel
the article talks about the pollution of “aerosolized” aluminum particles in the atmosphere, not about the kinetic hazard.
I’d be curious to see the actual design. How much existing aluminum are they replacing with wood? Assuming the wood is purely structural, doesn’t that leave solar panels and internal propulsion/electronics as is which happen to make up the most of a satellite’s volume?
We get showered by meteors all the time, I don't see how satellites create unique pollution. Or do artificial satellites reenter earth in larger magnitudes than meteors?
I'm with you it seems a little silly but looking into the question:
NASA https://science.nasa.gov/solar-system/meteors-meteorites/ gives the figure 44,000 kg of material falls to the Earth each day and that "Almost all" is vaporized in the atmosphere. A satellite can range from micro (~100 kg) to intermediate (~3000 kg) to extra heavy (>7000 kg). For reference Starlink started ~250 kg and the v2 are ~1250 kg. On average there should be ~10 deorbits per day at the current point, so safe to say at least an additional 25% over normal already.
The confusion that's left is how much of the material that naturally falls to the earth each day is also consider "polluting" and whether tons of such material is noteworthy pollution to be concerned about in spaceflight (for comparison global CO2 emissions are ~36,820,000,000,000 kg per year and a liter different in rocket fuel usage probably a lot larger pollution difference).
Some satellites have thick-walled chambers for spectral analysis, thick enough to have >1/10,000 chance of surviving reentry.
We had to convince the FAA that our vacuum chamber could be made from steel and also would not survive reentry.
Satellites decompose into very small and sharp shards. The shards them obit earth at a very high speed.
I’m guessing meteors don’t decompose into very small and sharp shards that orbit earth at a very high speed.
What does this have to do with the pollution being referred to in the article:
> All the satellites which re-enter the Earth’s atmosphere burn and create tiny alumina particles, which will float in the upper atmosphere for many years,” Takao Doi, a Japanese astronaut and aerospace engineer with Kyoto University, warned recently. “Eventually, it will affect the environment of the Earth.”
Shards or no shards, if a satellite weighs 1,000 kg then that's a maximum of 1,000 kg of aluminum particles that can burn up in the atmosphere - regardless how they do it.
The article mentions alumina particles, which is not something I'm familiar with
Would it burn to ash at those speeds?
Doesn’t wood need oxygen to burn?
Not with friction from the atmosphere
https://en.wikipedia.org/wiki/Pyrolysis