4 ms·

Even if we break it up and capture a chunk it would be both a huge wealth of knowledge and if the chunks was big enough it could be extremely useful construct m

Even if we break it up and capture a chunk it would be both a huge wealth of knowledge and if the chunks was big enough it could be extremely useful construct material

eesmith 4y ago
I don't think you have an idea of the delta-V issue. https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20DW https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20D... says its speed will be roughly 11 km/s (were Earth not present) and an impact velocity of 15km/s (were Earth in the way; Earth's gravity speeds things up). If we do that with rocket power, and not some complicated gravity-assist path, then we can look at New Horizons. That used an Atlas V rocket at around 570 tons to get the 478 kg payload up to 16 km/s. That's a 1:1000 mass ratio. Once you've caught up, you've got to turn things around and slow down. But you're talking about another 1:1000 or more mass ratio, leaving you with a few grams of material. This is all hand-waving to give a rough idea of the problem. We've had a few asteroid sample-return mission. Hayabusa2 returned a few grams of material from 162173 Ryugu. The hope is that OSIRIS-REx will return 60 grams from 101955 Bennu this fall. These used ion thrusters (more efficient than chemical rockets) and atmospheric braking to help slow down. Still, none of this is anywhere near being useful as construction material. It would be far cheaper to bring it up from Earth.
- hd95489 4y ago
  I was thinking gravity and atmospheric assists to get delta v required. You have to do something complex to pull this off. Or blow off a small piece to deflect the main bit and capture a small artifact
  - eesmith 4y ago
    Yes, that's what the current asteroid return missions already do, just to return tens of grams of material. That's not enough to use as building materials.

4 ms·

Even if we break it up and capture a chunk it would be both a huge wealth of knowledge and if the chunks was big enough it could be extremely useful construct m

by hd95489 4y ago

Even if we break it up and capture a chunk it would be both a huge wealth of knowledge and if the chunks was big enough it could be extremely useful construct material

eesmith 4y ago
I don't think you have an idea of the delta-V issue. https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20DW https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20D... says its speed will be roughly 11 km/s (were Earth not present) and an impact velocity of 15km/s (were Earth in the way; Earth's gravity speeds things up). If we do that with rocket power, and not some complicated gravity-assist path, then we can look at New Horizons. That used an Atlas V rocket at around 570 tons to get the 478 kg payload up to 16 km/s. That's a 1:1000 mass ratio. Once you've caught up, you've got to turn things around and slow down. But you're talking about another 1:1000 or more mass ratio, leaving you with a few grams of material. This is all hand-waving to give a rough idea of the problem. We've had a few asteroid sample-return mission. Hayabusa2 returned a few grams of material from 162173 Ryugu. The hope is that OSIRIS-REx will return 60 grams from 101955 Bennu this fall. These used ion thrusters (more efficient than chemical rockets) and atmospheric braking to help slow down. Still, none of this is anywhere near being useful as construction material. It would be far cheaper to bring it up from Earth.
- hd95489 4y ago
  I was thinking gravity and atmospheric assists to get delta v required. You have to do something complex to pull this off. Or blow off a small piece to deflect the main bit and capture a small artifact
  - eesmith 4y ago
    Yes, that's what the current asteroid return missions already do, just to return tens of grams of material. That's not enough to use as building materials.