3 ms·

Cost per delta-v is dropping, hopefully by an lot if/when we get reusable rockets. Given that near earth asteroids require dramatically less delta-v than Mars

Cost per delta-v is dropping, hopefully by an lot if/when we get reusable rockets. Given that near earth asteroids require dramatically less delta-v than Mars (because no gravity well) and some are high in platinum, iridium and other expensive things it sounds like mining asteroids could be cost effective soon. I'm not arguing with your numbers, but could you spell out your calculations a bit more? How are you calculating the cost of delta-v per kg?

PeterisP 12y ago
Cost is dropping, but even if/when we reduce the costs by 10-20 times (as expected by the rocket reusability plans) then it's still unprofitable. Even if Santa gave us a free colony of Mars and the rocket costs dropped as much as we hope and Mars was covered with bricks of platinum and iridium - even then it would be economical to simply leave it alone.
- dredmorbius 12y ago
  As I asked the other reply: do you have any substantiation of this? I do tend to agree with your conclusions. Just looking for solid sources / methods.
dredmorbius 12y ago
I've had similar discussions previously. I've yet to see anyone post any credible (or for the most part any) estimates of cost per kg. You'll find a list of delta-v budgets here: http://en.wikipedia.org/wiki/Delta-v_budget http://en.wikipedia.org/wiki/Delta-v_budget Hrm. Some low-cost references: LEO on the Cheap http://www.quarkweb.com/nqc/lib/gencoll/leocheap_ch9.htm http://www.quarkweb.com/nqc/lib/gencoll/leocheap_ch9.htm "Highly Reusable Space Transportation: Approaches for Reducing ETO Launch Costs to $100-200 per Pound of Payload" http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960007723.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1996000... (Pre-1995 paper). Both references are vastly lower than any extant launch system: Falcon 9 v 1.1- $4,109 DNEPR- $3,784 Ariane 5- $10,476 Delta IV- $13,072 Atlas V- $13,182 http://space.stackexchange.com/questions/1989/what-is-the-current-cost-per-pound-to-send-something-into-leo http://space.stackexchange.com/questions/1989/what-is-the-cu... (Cites a Wikipedia article which doesn't / no longer presents the data in $/kg). And more: http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/Space_Transportation_Costs_Trends_0902.pdf http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/S...
- JoeAltmaier 12y ago
  Confused: what relationship does the launch cost from earth have, to the weight of returned material from asteroids/mars?
  - dredmorbius 12y ago
    Rocket equation. There's presently no way of constructing or provisioning a rocket entirely in space without first lifting materials (or the entire craft) from Earth. Should there be, whatever costs are associated with that will shift the equation here. In the meantime, you're stuck with the reality that whatever mass you plan on transporting to the asteroid, and whatever mass is required to haul back your loot, needs to be boosted from Earth's surface to LEO. The tyranny of the rocket equation dictates what delta-v costs you. Trips with burns at both ends are vastly more expensive than those with burns at only one. So, yes, aerobraking (on return to Earth) is a highly cost-effective method, but that's going to require budgeting for the mass of your reentry shielding and landing mechanism (likely parachutes). Ultimately, you're looking at a high-speed, high-temperature reentry, atmospheric slowing, and an ultimate soft-ish landing of whatever you've recovered. While ion rockets have been proposed as vastly more mass-efficient than chemical rockets, existing designs based on xeon rely on an element whose prevalence in known space environments is quite low. The one exception is Jupiter, but that's the second deepest gravity well in the Solar System: Within the Solar System, the nucleon fraction of xenon is 1.56 × 10−8, for an abundance of approximately one part in 630 thousand of the total mass.[53] Xenon is relatively rare in the Sun's atmosphere, on Earth, and in asteroids and comets. The planet Jupiter has an unusually high abundance of xenon in its atmosphere; about 2.6 times as much as the Sun. http://en.wikipedia.org/wiki/Xenon#Occurrence_and_production http://en.wikipedia.org/wiki/Xenon#Occurrence_and_production
    - JoeAltmaier 12y ago
      Sure I get that. Landing via parachute remove almost all the return cost. Leaving the cost of a mechanism in space that can run for years, delivering asteroid metal to earth. Its disingenuous to claim a fixed startup cost prevents profiting from what essentially becomes an industrial infrastructure. It costs billions to create a new oil refinery, yet we do it all the time.
dredmorbius 12y ago
Oh, and per the reference I pulled up, cost per pound wasn't falling appreciably by 2000. Yes, we're another 14, call it 15 years further on. But as the chart on page 4 of the Futron report shows, aside from a big drop in 1992, there was effectively no movement during the 1990s. http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/Space_Transportation_Costs_Trends_0902.pdf http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/S...

PeterisP 12y ago

Cost is dropping, but even if/when we reduce the costs by 10-20 times (as expected by the rocket reusability plans) then it's still unprofitable. Even if Santa gave us a free colony of Mars and the rocket costs dropped as much as we hope and Mars was covered with bricks of platinum and iridium - even then it would be economical to simply leave it alone.

dredmorbius 12y ago
As I asked the other reply: do you have any substantiation of this? I do tend to agree with your conclusions. Just looking for solid sources / methods.

dredmorbius 12y ago

I've had similar discussions previously. I've yet to see anyone post any credible (or for the most part any) estimates of cost per kg. You'll find a list of delta-v budgets here: http://en.wikipedia.org/wiki/Delta-v_budget http://en.wikipedia.org/wiki/Delta-v_budget Hrm. Some low-cost references: LEO on the Cheap http://www.quarkweb.com/nqc/lib/gencoll/leocheap_ch9.htm http://www.quarkweb.com/nqc/lib/gencoll/leocheap_ch9.htm "Highly Reusable Space Transportation: Approaches for Reducing ETO Launch Costs to $100-200 per Pound of Payload" http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960007723.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1996000... (Pre-1995 paper). Both references are vastly lower than any extant launch system: Falcon 9 v 1.1- $4,109 DNEPR- $3,784 Ariane 5- $10,476 Delta IV- $13,072 Atlas V- $13,182 http://space.stackexchange.com/questions/1989/what-is-the-current-cost-per-pound-to-send-something-into-leo http://space.stackexchange.com/questions/1989/what-is-the-cu... (Cites a Wikipedia article which doesn't / no longer presents the data in $/kg). And more: http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/Space_Transportation_Costs_Trends_0902.pdf http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/S...

JoeAltmaier 12y ago
Confused: what relationship does the launch cost from earth have, to the weight of returned material from asteroids/mars?
- dredmorbius 12y ago
  Rocket equation. There's presently no way of constructing or provisioning a rocket entirely in space without first lifting materials (or the entire craft) from Earth. Should there be, whatever costs are associated with that will shift the equation here. In the meantime, you're stuck with the reality that whatever mass you plan on transporting to the asteroid, and whatever mass is required to haul back your loot, needs to be boosted from Earth's surface to LEO. The tyranny of the rocket equation dictates what delta-v costs you. Trips with burns at both ends are vastly more expensive than those with burns at only one. So, yes, aerobraking (on return to Earth) is a highly cost-effective method, but that's going to require budgeting for the mass of your reentry shielding and landing mechanism (likely parachutes). Ultimately, you're looking at a high-speed, high-temperature reentry, atmospheric slowing, and an ultimate soft-ish landing of whatever you've recovered. While ion rockets have been proposed as vastly more mass-efficient than chemical rockets, existing designs based on xeon rely on an element whose prevalence in known space environments is quite low. The one exception is Jupiter, but that's the second deepest gravity well in the Solar System: Within the Solar System, the nucleon fraction of xenon is 1.56 × 10−8, for an abundance of approximately one part in 630 thousand of the total mass.[53] Xenon is relatively rare in the Sun's atmosphere, on Earth, and in asteroids and comets. The planet Jupiter has an unusually high abundance of xenon in its atmosphere; about 2.6 times as much as the Sun. http://en.wikipedia.org/wiki/Xenon#Occurrence_and_production http://en.wikipedia.org/wiki/Xenon#Occurrence_and_production
  - JoeAltmaier 12y ago
    Sure I get that. Landing via parachute remove almost all the return cost. Leaving the cost of a mechanism in space that can run for years, delivering asteroid metal to earth. Its disingenuous to claim a fixed startup cost prevents profiting from what essentially becomes an industrial infrastructure. It costs billions to create a new oil refinery, yet we do it all the time.

dredmorbius 12y ago

Oh, and per the reference I pulled up, cost per pound wasn't falling appreciably by 2000. Yes, we're another 14, call it 15 years further on. But as the chart on page 4 of the Futron report shows, aside from a big drop in 1992, there was effectively no movement during the 1990s. http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/Space_Transportation_Costs_Trends_0902.pdf http://www.futron.com/upload/wysiwyg/Resources/Whitepapers/S...