A_M_Swallow - 23/2/2008 11:25 PMAircraft normally fly with the airline's symbol on their tails, not the manufactures. NASA will be paying for the COTS II launches.
Jim - 24/2/2008 8:48 AMQuoteA_M_Swallow - 23/2/2008 11:25 PMAircraft normally fly with the airline's symbol on their tails, not the manufactures. NASA will be paying for the COTS II launches.Airline analogy is not applicable. NASA is not an operator like the airlines. The manufacturer is the operator. There will be both symbols
kevin-rf - 23/2/2008 8:27 PM (blah, blah...) if politics dictated a cape launch?
"politics will dictate the location" can be interpreted in different ways. One way in which it will not dictate the location is politicians putting pressure on NASA; NASA is contributing $170M, advice on how to approach ISS safely, and, of course, ultimate authority to approach ISS with all that entails. But not terms and conditions on how and where to launch.
That said, we will choose the location that makes it easiest for us to acheive a successful demo. Cost control being one of the key ingredients of success, the decision will be heavily tilted in favor of the location that requires the least amount of nonrecurring cost (to facilitize) without absolutely killing the recurring (operating) cost. If one of the spaceport authorities (Florida or MARS) somehow manages to obtain the funding to fully equip a suitable launch pad, assembly building, etc., so all we have to do is rent it rather than build it, we'll go there.
In that sense ($'s) "politics" could "dictate" the launch site... maybe that's what you meant...
Comga - 23/2/2008 7:19 PM I was speaking of the AA SMD, Alan Stern.
Ah! You're right! I missed the scientist part: Alan is a card-carrying scientist, while MDG and I are mere engineers.
"An engineer is always looking for solutions for his problems; a scientist is always looking for problems for his solutions" (anonymous)
Jim - 23/2/2008 9:10 PMQuotekevin-rf - 23/2/2008 9:27 PMQuoteantonioe - 23/2/2008 4:45 PMI would bet a chocolate milkshake that you go out on the street and five out of ten people would answer "yes", but the thought of winning that bet is too depressing...Sadly I fear it would be somewhere north of nine out of ten....On a more serious note, how much of a cargo mass to ISS hit would Orbital's COTS proposal take if politics dictated a cape launch?Hit? It should increase
kevin-rf - 23/2/2008 9:27 PMQuoteantonioe - 23/2/2008 4:45 PMI would bet a chocolate milkshake that you go out on the street and five out of ten people would answer "yes", but the thought of winning that bet is too depressing...Sadly I fear it would be somewhere north of nine out of ten....On a more serious note, how much of a cargo mass to ISS hit would Orbital's COTS proposal take if politics dictated a cape launch?
antonioe - 23/2/2008 4:45 PMI would bet a chocolate milkshake that you go out on the street and five out of ten people would answer "yes", but the thought of winning that bet is too depressing...
I would bet a chocolate milkshake that you go out on the street and five out of ten people would answer "yes", but the thought of winning that bet is too depressing...
Jim - 24/2/2008 2:48 AMQuoteA_M_Swallow - 23/2/2008 11:25 PMAircraft normally fly with the airline's symbol on their tails, not the manufactures. NASA will be paying for the COTS II launches.Airline analogy is not applicable. NASA is not an operator like the airlines. The manufacturer is the operator. There will be both symbols
antonioe - 24/2/2008 8:58 PM"An engineer is always looking for solutions for his problems; a scientist is always looking for problems for his solutions" (anonymous)
edkyle99 - 24/2/2008 12:13 AMIt is 1:30 AM where I am right now, but my watch says 11:00 PM. I'm from Chicago. Can anyone guess where I might be? - Ed Kyle
edkyle99 - 24/2/2008 11:13 PMIt is 1:30 AM where I am right now, but my watch says 11:00 PM. I'm from Chicago. Can anyone guess where I might be? - Ed Kyle
edkyle99 - 24/2/2008 11:13 PM The Cape provides a bit more earth-rotation velocity than Wallops, but a 51.6 degree inclination launch would use less of the Cape's earth-rotation velocity than a Wallops launch would use of its own earth-rotation velocity. I'm too tired to do the math right now, so I have no idea which one is the better site for an ISS launch.
Well, i *JUST* happen to have two Visual Basic macros for Excel that help a bit. The first one estimates (geometrically) the launch azimuth required to hit a desired inclination from a certain latitude, given the target orbital altitude (it's an estimation - accurate results depend on the particulars of the trajectory, e.g., slow liquid Ariane 5 style vs. fast, solid, taurus style; but, hey, it's a lot better than guessing!)
The second function calculates - also geometrically - the inertial velocity due to earth rotation in the direction of the launch azimuth at a given latitude. Like the other function, this is an approximation to the performance impact, but, again, it's better than a guess...
And the results are:
WFF
CCAFS
Although these are approximations, I'd say the result is a tie. Downrange issues (stage imnpacts, overflights, etc) probably have more of an impact, and I can't evaluate them without a more detailed analysis, which we have not done yet. Even then I expect nearly a wash.
meiza - 25/2/2008 1:57 PM I find the result very counterintuitive. edit: It must be due to direction of the orbit over the launch site?
Well, from a northern latitude, you shoot closer to East to get to the desired inclination than from a southern latitude, and that helps in getting more of the Eastwards Earth Rotational Velocity (EERV) in the direction of launch, but on the other hand the amount of EERV up north is lower than further south. I guess one effect cancels the other.
Also note that the launch azimuth numbers I gave in the table are the ascending ones; you get the same results if you mirror image them w.r.t. East, i.e. 129.9 deg from WFF and 137.2 deg from CCAFS (the approximate rotational velocity help being the same for both the ascending and descending cases.) From CCAFS, range limits may preclude use of the the ascending azimuth (anybody knows for sure?)
BTW, from a latitude of 51.6 deg, my Excel calculations show a launch azimuth of 90 deg (duh...) and a net contribution of rotational velocity in the direction of launch of 289 m/s. Not a big difference from 278 (CCAFS) or 282 (WFF). What's at 51.6 deg north latitude?
dmc6960 - 25/2/2008 10:57 AMQuoteedkyle99 - 24/2/2008 11:13 PMIt is 1:30 AM where I am right now, but my watch says 11:00 PM. I'm from Chicago. Can anyone guess where I might be? - Ed KyleNewfoundland, Canada.
Curious, do you work for PlanetSpace?
antonioe - 25/2/2008 1:23 PM What's at 51.6 deg north latitude?
antonioe - 25/2/2008 2:23 PM What's at 51.6 deg north latitude?
I mean it tongue in cheek as an alternate COTS launch site to either CCAFS or WFF, in view of the furor that the WFF idea has caused...
By the way, the New Mexico congressional delegation wants to have a word with us.
antonioe - 25/2/2008 12:23 PM BTW, from a latitude of 51.6 deg, my Excel calculations show a launch azimuth of 90 deg (duh...) and a net contribution of rotational velocity in the direction of launch of 289 m/s. Not a big difference from 278 (CCAFS) or 282 (WFF). What's at 51.6 deg north latitude?
Vostokny, the proposed new Russian launch site, is about 50 deg N.
antonioe - 25/2/2008 2:23 PMFrom CCAFS, range limits may preclude use of the the ascending azimuth (anybody knows for sure?)
Antares - 25/2/2008 10:36 PM Quoteantonioe - 25/2/2008 2:23 PM From CCAFS, range limits may preclude use of the the ascending azimuth (anybody knows for sure?) IIUC the terminology and I'm 98% sure I do, ETR limits actually preclude descending azimuth from the Cape to the ISS. The Shuttle always launches to the north now.
antonioe - 25/2/2008 2:23 PM From CCAFS, range limits may preclude use of the the ascending azimuth (anybody knows for sure?)
Uhh... are you sure that's not a Shuttle-unique situation due to the STS transatlantic abort sites (Rota, Zaragoza)? Somehow I remember that ELV's going to 51.6 are sent descending due to excessive Pc's over Europe... lower Pc's over Africa (stages are faster by the time the IIP's transit Africa). STS may not have suitable TAL's when going descending to 51.6... maybe Dakar?
I really should stop speculating about things I don't know... I apologize.
Danderman - 25/2/2008 8:58 PM Vostokny, the proposed new Russian launch site, is about 50 deg N.
Do they have a clear shot Eastwards? Unlike Baikonur, where the Big Eastern Country prevents them from shooting due east..?
