Even solar thermal engines need a throat and nozzle. A weird shaped combustion chamber can lead to instabilities. So just heating a rock is unlikely to work very well.Having a drill convert the asteroid into a powder that is feed into the engine may work. This can be tested on Earth.
New thread, you guys.
Quote from: Robotbeat on 07/03/2013 06:51 pmNew thread, you guys. I believe my above response is relevant to the ARM in that it gives context. ISRU is the best reason to retrieve an asteroid so using a simpler cheaper much more robust system that uses it from the start is a better way to go (and this is especially true for planetary defense) IMO. YMMV
QuoteDoes any one have an estimate on how much Xenon costs per KG?About $1200. Google is your friend, if you use it. 12,000 kg X $1200 / kg is $14.4 million. Fuel (or in this case, reaction mass) is cheap compared to the other costs of a space mission. Still, using Argon would save a few million dollars. At $5.00 per kg, 12,000 kg of Ar comes in at $60,000.
Does any one have an estimate on how much Xenon costs per KG?
According to Wikipedia Xenon production is 5-7,000m3 per year, which equates to about 35 tons. A single order for 12 tons might push up the price by a lot given production rates are determined by the much bigger market of oxygen/nitrogen distillation.
According to Wikipedia Xenon production is 5-7,000m3 per year, which equates to about 35 tons. A single order for 12 tons might push up the price by a lot given production rates are determined by the much bigger market of oxygen/nitrogen distillation. Any more news on this mission?
Quote from: Solman on 07/03/2013 06:57 pmQuote from: Robotbeat on 07/03/2013 06:51 pmNew thread, you guys. I believe my above response is relevant to the ARM in that it gives context. ISRU is the best reason to retrieve an asteroid so using a simpler cheaper much more robust system that uses it from the start is a better way to go (and this is especially true for planetary defense) IMO. YMMVNo, it's not because the concept is near-term (have to start building it very, very soon). Yours is more of an advanced concepts idea. Electric propulsion is quite mature right now, even if the exact thruster make may not have flown yet.
The actual Keck spacecraft asteroid capture mechanism has not even been built much less tested on orbit.
Assumes all technologies are at TRL Level 6 -- the estimate does not include any cost for technology development up to TRL 6.
Quote from: Solman on 07/07/2013 08:31 pmThe actual Keck spacecraft asteroid capture mechanism has not even been built much less tested on orbit.The bag is assumed to be at TRL-6.Quote from: the Keck PaperAssumes all technologies are at TRL Level 6 -- the estimate does not include any cost for technology development up to TRL 6.The experts wouldn't make these assumptions if they were unwarranted. Please let the experts do their work.
Quote from: alexterrell on 07/05/2013 12:50 pmAccording to Wikipedia Xenon production is 5-7,000m3 per year, which equates to about 35 tons. A single order for 12 tons might push up the price by a lot given production rates are determined by the much bigger market of oxygen/nitrogen distillation. Any more news on this mission?Man, that's a large portion of the Xenon market! Any ideas on who NASA is buying from? They should start stockpiling!
Quote from: ClaytonBirchenough on 07/07/2013 12:58 amQuote from: alexterrell on 07/05/2013 12:50 pmAccording to Wikipedia Xenon production is 5-7,000m3 per year, which equates to about 35 tons. A single order for 12 tons might push up the price by a lot given production rates are determined by the much bigger market of oxygen/nitrogen distillation. Any more news on this mission?Man, that's a large portion of the Xenon market! Any ideas on who NASA is buying from? They should start stockpiling!You are correct. We were told it will take about 1/3 of the world's supply of Xenon to fully load the spacecraft. It'll take two years to produce, transport, and stored in a refrigerated tank at KSC. It is a US company, but I can't say who.
It was mentioned that this is more of a technology demonstration than exploration. As such it would be the largest such tech demo NASA has ever done, to my knowledge. But as a demonstration it has the potential to lay the foundation for true commercial space mining. The rewards are huge.
Retrieving an object of random composition based solely upon the convenience of its delta-vee and its orbital characteristics is not how mining is done, or will be done.