A kerosene-fueled X-33 as a single stage to orbit vehicle.
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From: J. Clarke on 30 Mar 2010 10:11 On 3/30/2010 9:52 AM, hallerb(a)aol.com wrote: > >>> your a small business owner who owns a van for deliveries but when it >>> breaks down you use your car, its not convenient or efficent but it >>> gets the job done........ >> >> As a small business owner I don't pay millions of dollars for a car when >> I need a truck either. >> > > You would if it were profitable enough Nope. I might pay millions of dollars for a car too but I wouldn't delude myself that it was a truck.
From: J. Clarke on 30 Mar 2010 10:11 On 3/30/2010 9:49 AM, hallerb(a)aol.com wrote: > On Mar 30, 9:25�am, "J. Clarke"<jclarke.use...(a)cox.net> wrote: >> On 3/30/2010 7:55 AM, hall...(a)aol.com wrote: >> >> >> >> >> >>> On Mar 30, 1:28 am, "J. Clarke"<jclarke.use...(a)cox.net> �wrote: >>>> On 3/29/2010 11:22 PM, Pat Flannery wrote: >> >>>>> On 3/29/2010 2:04 PM, J. Clarke wrote: >> >>>>>> So is there a "generic" set of requirements published anywhere for a >>>>>> satellite? If it was practical to mass-produce generic satellites that >>>>>> will satisfy all customers don't you think someone would be doing it by >>>>>> now? >> >>>>> That's how commercial comsats are designed. >>>>> Individual countries purchase satellites of the same design: >>>>> http://www.ssloral.com/html/satexp/intelsat.html >> >>>> So let's see, a company makes 30 satellites for Intelsat Corporation, >>>> and from that you conclude that "different countries purchase satellites >>>> of the same design". >> >>>> There are approximately 300 active geostationary satellites which means >>>> that approximately 270 of them are _not_ of the "generic" design that >>>> you linked. And then there are all the non geostationary >>>> satellites--Inmarsat and Iridium and GPS and providers of numerous other >>>> services. >> >>>> So how are you going to make a one size fits all generic satellite that >>>> does all those jobs and doesn't require an Orion to put it up? >> >>> The companies who NEED the back up capacity join together to build >>> back up sats. >> >> And of course they all agree on a feature set and all are willing to pay >> the cost to launch the features they don't want or need. >> >>> Now the backu may not be optimized for wherever it ends up but will be >>> far better than nothing. >> >> How is something that doesn't do the required job "better than nothing"? >> >>> Plus once a actual replacement arrives the fast fill in can be sold or >>> leased and �moved to a new location. >> >> Moving satellites isn't like moving cars in a parking lot. �You act like >> it's a trivial task. �And where are you going to move it to? >> >>> your a small business owner who owns a van for deliveries but when it >>> breaks down you use your car, its not convenient or efficent but it >>> gets the job done........ >> >> As a small business owner I don't pay millions of dollars for a car when >> I need a truck either. >> >>> there was a whole story about this some years ago, KSC was to get a >>> dedicated facility with generic sats in storage >> >> What do you mean "was to get"? �Are you saying that it got as far as >> NASA requesting funding from Congress or are you saying that somebody >> was talking about it in a bar one night and Avleak decided to run with >> the story?- Hide quoted text - >> >> - Show quoted text - > > Florida talked about putting up bucks for the facility. To get more > jobs at KSC. > Actually moving clark belt birds is pretty easy, companies like dish > network do it all the time. If that's where they are. How about moving an Iridium? > Either quit stationkeeping and they begin moving with minimal fuel > use, or go the other direction burning fuel They begin drifting you mean. > This sort of fast replacement would be for emergency use. So how much more does it cost to have a big enough booster to put up a generic one size fits all satellite than to put a smaller spare on orbit to begin with? > Now just IMAGINE if a satellite TV provider suddenly had a major sat > loss. He'd bring in one of his on orbit purpose-designed spares and be back online more quickly than launching some one-size-fits-all generic. > They could lose a substantial amount of business plus with 11 million > subscribers they cant just go repointing dishes. No, they bring in an on-orbit spare. Lot quicker than boosting from the ground and it's cheaper to keep it there than to keep it in a silo. You don't need to run utilities or pay security or anything else for something on orbit and the cost of putting it there is the same if you do it today as if you did it a year ago. > I will look around for a reference, it was on the old florida today > website years ago It sounds like the kind of thing a state legislator would come up with, present, and after they quit laughing at him go home to his constituents and tell them all about the bill he proposed that's going to bring new jobs to the area and how the EEEEEEEVVVVVVVIIIIIIILLLLLLL republicrats or demicans or whoever the opposing party is blocked it and ruined their lives.
From: Craig Bingman on 3 Apr 2010 21:17 In article <d_WdnZhAS9rnDzrWnZ2dnUVZ_jKdnZ2d(a)posted.northdakotatelephone>, Pat Flannery <flanner(a)daktel.com> wrote: (quoting someone else) >Fluorine-deuterium? Oh, that will be cheap to use as fuel. ;-) > >Pat Hi Pat, I don't understand how deuterium would help at all. It weighs twice as much, it has no more enthalpy of combustion, and i would think that the increased mass of deuterium would hurt specific impulse by increasing the effective molecular weight of the exhaust. Can you or someone else give me a reality check on that one? (Or was it an April Fools thing that I missed?) Craig -- -- cbingman(a)panix.com
From: Pat Flannery on 4 Apr 2010 03:45 On 4/3/2010 5:17 PM, Craig Bingman wrote: > > Hi Pat, > > I don't understand how deuterium would help at all. It weighs twice as much, > it has no more enthalpy of combustion, and i would think that the increased > mass of deuterium would hurt specific impulse by increasing the effective > molecular weight of the exhaust. > > Can you or someone else give me a reality check on that one? Here's the article where that combo is mentioned, that came out well before April 1st: http://www.thespacereview.com/article/1591/1 The part before that mentions the problems with fluorine: http://www.thespacereview.com/article/1580/1 According to one poster to this thread, the advantage liquid deuterium gives you is that it's a lot more dense by volume than standard liquid hydrogen, so you can decrease the size of your fuel tanks for the same amount of energy content. Pat
From: Marvin the Martian on 4 Apr 2010 03:57
On Sun, 04 Apr 2010 01:17:38 +0000, Craig Bingman wrote: > In article > <d_WdnZhAS9rnDzrWnZ2dnUVZ_jKdnZ2d(a)posted.northdakotatelephone>, Pat > Flannery <flanner(a)daktel.com> wrote: (quoting someone else) >>Fluorine-deuterium? Oh, that will be cheap to use as fuel. ;-) >> >>Pat > > Hi Pat, > > I don't understand how deuterium would help at all. It weighs twice as > much, it has no more enthalpy of combustion, and i would think that the > increased mass of deuterium would hurt specific impulse by increasing > the effective molecular weight of the exhaust. > > Can you or someone else give me a reality check on that one? You're exactly right. You noticed that Pat doesn't know what he's talking about. He doesn't understand the rocket equation or rocket physics at all. > (Or was it an April Fools thing that I missed?) > > Craig > -- |