Quote from: antonioe on 12/27/2008 01:34 am200 tons a year!!!??? Wow! that would warrant development of a Taurus IV, or a Falcon 27!!! And a x5 scale Cygnus Service Module!!! (although why would anyone put a fuel depot in LEO, vs. simply assembling already fueled tanks on orbit, I can't fathom).I guess you could construct a situation where a tug that remains in orbit (but has in-orbit refueling capability) and is refueled by the same tanks it carries to the "rendezvous point" (depot or spacecraft under assembly) may be more efficient than launching a suitably-sized single-use SM (with just enough fuel for the rendezvous) with each tank.Without going into the Propellant Depot (PD) discussionhttp://forum.nasaspaceflight.com/index.php?topic=12338.0the 200 tons sounds like the fuel for the manned Mars mission. That spacecraft may prefer to carry a single large fuel tank instead of 10 off 20 tonne fuel tanks with associated plumbing. The fuel being lifted on EELV and CRS LV.The PD operator would be looking to fuel the 2 (or with luck 4) Moon missions per year. That is the Earth Departure Stage LEO to TLI and the Altair lunar lander. (NASA's willingness to buy the propellant is a different but related matter.)As for the tug - one idea is to make the tanker rockets as simple and cheap as possible, anything complex being performed by the tug and depot. Automated docking with the depot counts as complex; this is likely to be the same order of complexity as docking with the ISS. By using a tug the tankers would not need a RCS for instance. The LV simply lift the tanks to LEO and the tug comes to collect and dock the tanks.A cost saving comes from only a single set of navigation rockets on the tug being needed as against a set of rockets per tanker, eliminating say 50 sets of RCS rockets. The tug could also manoeuvre the Moon/GEO/Mars/beyond spacecraft being fuelled when they dock with the depot.
200 tons a year!!!??? Wow! that would warrant development of a Taurus IV, or a Falcon 27!!! And a x5 scale Cygnus Service Module!!! (although why would anyone put a fuel depot in LEO, vs. simply assembling already fueled tanks on orbit, I can't fathom).I guess you could construct a situation where a tug that remains in orbit (but has in-orbit refueling capability) and is refueled by the same tanks it carries to the "rendezvous point" (depot or spacecraft under assembly) may be more efficient than launching a suitably-sized single-use SM (with just enough fuel for the rendezvous) with each tank.
1. I wonder if OSC ever plans on recovering the first stage of Taurus II like spacex is going to with Falcon 9?2. Doing so might go a long way in bringing up the flight rates.
Quote from: Patchouli on 12/29/2008 12:28 am1. I wonder if OSC ever plans on recovering the first stage of Taurus II like spacex is going to with Falcon 9?2. Doing so might go a long way in bringing up the flight rates.1. No, it has be stated over and over by antonioe that it is not worth the effort for the low flight rates2. Reusability does not increase flight rates
I'm pretty sure the number of launches you contract has something to do with your flight rate, especially if you can accommodate those extra launches without having to manufacture everything from scratch.
Spacex hopes to cut 50% off the launch price if reusability pans out.
And what the amount of time refurbishment takes has to do with anything is a bit of a mystery too. It would obviously not be done at expense of new engine production.{snip}
How Jim can claim that the amount of business you have doesn't affect your flight rate is beyond me. And what the amount of time refurbishment takes has to do with anything is a bit of a mystery too.
. Not everybody will need 100% of the capacity.
Quote from: nomadd22 on 12/29/2008 06:18 am How Jim can claim that the amount of business you have doesn't affect your flight rate is beyond me. And what the amount of time refurbishment takes has to do with anything is a bit of a mystery too.Obviously you don't understand flight hardware processing.It doesn't matter how many flights you have on contract because the hardware and facilities have a throughput limit. Prices affect the number of contracts you get, not the flight rateYes, you can increase flight rate by having multiple production lines and multiple launch pads and crews. But we are not talking about those kind of flight rates
Quote from: nomadd22 on 12/29/2008 01:03 amI'm pretty sure the number of launches you contract has something to do with your flight rate, especially if you can accommodate those extra launches without having to manufacture everything from scratch.Incorrect. Contracted launches and reusability are independent of launch processing and the flight rate derived from it.Refurbishment may take longer than production. Launch processing may be longer than production rate
How much of "launch processing" can be attribute to "payload processing," on average? I was wondering if there would ever be any benefit to designing an LV to be handled more like a V-2 (or in more modern terms, a road-mobile ICBM). Integrate everything onto the back of a big truck in a hangar, then send the truck (and trucks of fuel. oxydizer) to an otherwise fairly primitive launch site.
Quote from: William Barton on 12/29/2008 12:03 pmHow much of "launch processing" can be attribute to "payload processing," on average? I was wondering if there would ever be any benefit to designing an LV to be handled more like a V-2 (or in more modern terms, a road-mobile ICBM). Integrate everything onto the back of a big truck in a hangar, then send the truck (and trucks of fuel. oxydizer) to an otherwise fairly primitive launch site.For Atlas V and Delta II, the payload is mated to the LV less than 2 weeks before launch. Delta IV is a little longer but was be to shorterWhat was the success rate of the V-2?
What was the success rate of the V-2?
http://www.theotherside.co.uk/tm-heritage/background/v1v2.htmFwiw, Astroautix has this discussion:http://www.astronautix.com/lvs/v2.htmDiscounting the 12% rejected by the combat units as "unsuitable for firing," (which one hopes wouldn't happen with a commercial satellit LV manufacturer), that leaves the 10% that failed within sight of the launch team, and another 10% that didn't get where they were supposed to gofor whatever reason. It doesn't sound like the field launch conditions contributed much to the failure rate.
Quote from: William Barton on 12/29/2008 12:29 pmhttp://www.theotherside.co.uk/tm-heritage/background/v1v2.htmFwiw, Astroautix has this discussion:http://www.astronautix.com/lvs/v2.htmDiscounting the 12% rejected by the combat units as "unsuitable for firing," (which one hopes wouldn't happen with a commercial satellit LV manufacturer), that leaves the 10% that failed within sight of the launch team, and another 10% that didn't get where they were supposed to gofor whatever reason. It doesn't sound like the field launch conditions contributed much to the failure rate.As I understand it, having a slave workforce of Jews whose families were being exterminated may have been a contributing factor to the high failure rate (i.e. intentional sabotage)