Author Topic: Air Force Identifies CCAFS southbound polar launch azimuth  (Read 15436 times)

Offline rpapo

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #20 on: 01/02/2018 02:30 PM »
Yes, I read the article.  It says that the second stage will be "high" by the time it passes over Cuba.  What it does not say is that it will only be "high" if everything works properly during the thrusting phase.  If something goes wrong, there will be a small probability that the second stage could crash onto Cuba.  The stage is still suborbital when the IIP passes over Cuba.
Which is what AFTS is all about.
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Online kenny008

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #21 on: 01/02/2018 04:49 PM »
Personally, I don't see this happening.  Flying over Cuba, with an IIP passing over the island during the thrusting phase, given the history of past flights on this corridor, presents too many opportunities for trouble.  If you think California is "hostile" to VAFB launches, what do you think Cuba is going to say?  Not to mention the more crowded sea lanes beneath such a launch track.  Liability would be an issue for a commercial contractor, etc.  That said, NASA apparently last used this corridor in 1965-66 to orbit TIROS satellites using Thor-Delta rockets.

 - Ed Kyle

To make sure I understand the article, it says that the southern launch corridor is "open."  It then says that Gen. Monteith is "confident" that they can launch in this direction.  It doesn't sound like they can offer this corridor yet, but what would they need to do to certify(?) this option?  Since the AF has done the calculations and the commander of the 45th Space Wing doesn't see any issues, seems pretty likely that they should be able to offer this to customers.

Offline woods170

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #22 on: 01/02/2018 05:01 PM »
Using NASA as a yardstick isn't always the way-to-go when dealing with USAF decisions.
Plus: did you bother to actually read the article?

Quote from: James Dean
“They crunched numbers for about eight months, and I am confident we can go south,” said Monteith (Brig. Gen. Wayne Monteith, commander of the 45th Space Wing)

Monteith did not detail the precise trajectory, but said it involved “a little jog shortly off the pad” to turn south once offshore, “and then we’d skirt Miami.”

The rocket’s first stage would drop safely before reaching Cuba, he said. The second stage would be so high up by the time it flew over the island that no special permissions would be required.
Yes, I read the article.  It says that the second stage will be "high" by the time it passes over Cuba.  What it does not say is that it will only be "high" if everything works properly during the thrusting phase.  If something goes wrong, there will be a small probability that the second stage could crash onto Cuba.  The stage is still suborbital when the IIP passes over Cuba.

 - Ed Kyle


And that is where AFTS comes in. All stages of a launcher must be equipped with it.

Offline deruch

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #23 on: 01/02/2018 08:12 PM »
I'm kind of surprised that James didn't contact the FAA for a comment.  For NSS launches, their input isn't involved.  But the discussion of potential benefits for commercial uses, most specifically by Blue Origin (potentially avoiding a VAFB pad), means that FAA approval of the launch path is also going to be necessary.  I think they use the same Ec numbers as the range as far as acceptiblilty is concerned, but I'm not sure whether they calculate them the same way.  Would have been nice to hear if they had seen the results of the USAF study and were preparing to consider future use.
« Last Edit: 01/02/2018 08:16 PM by deruch »
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Online Lars-J

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #24 on: 01/02/2018 09:07 PM »
I'm very skeptical of this... Here is a quick image showing the path. (from another thread) Note that it basically already overflies Bimini islands and edges Bahamas proper, not to mention all the disruption to shipping lanes and air traffic out of the Miami/Ft. Lauderdale area while also skimming the Florida coastline. There is a *LOT* of stuff to dodge.

It seems exceedingly optimistic. And that's not even getting into the Cuba overflight issues...
« Last Edit: 01/02/2018 09:09 PM by Lars-J »

Offline LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #25 on: 01/02/2018 11:21 PM »
I'm very skeptical of this... Here is a quick image showing the path. (from another thread) Note that it basically already overflies Bimini islands and edges Bahamas proper, not to mention all the disruption to shipping lanes and air traffic out of the Miami/Ft. Lauderdale area while also skimming the Florida coastline. There is a *LOT* of stuff to dodge.

It seems exceedingly optimistic. And that's not even getting into the Cuba overflight issues...
I'm not so skeptical.  Start on the line you drew (155 degrees), then as soon as possible make a right turn and head due south.  On the Atlas launch with TDRS-M, at 40 some miles out it was doing 4700 mph (=2100 m/s in rational units).  Doing a 25 degree turn at that point means the cost is 2100 * (1 - cos(25 degrees)) or about 200 m/s (actually somewhat less, since only the horizontal component needs fixing).   That's certainly not prohibitive.

Now the only island that gets passed over is Cuba, and the rocket is high and fast by then.
« Last Edit: 01/03/2018 12:31 AM by LouScheffer »

Offline kevin-rf

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #26 on: 01/03/2018 02:31 PM »
If this option had been available a few years ago, I wonder if we would have seen a west coast SpaceX pad.

So, it sounds like the only launches you won't be able to do from CCAFS are retrograde. With the only reasonable payloads for such an orbit being radar satellites that gain an resolution advantage from the higher ground speed. USA-234 and USA-247 being recent examples.
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Offline SWGlassPit

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #27 on: 01/03/2018 04:30 PM »
Quote
Beyond satellite launches, the corridor could open opportunities to rendezvous with the International Space Station as it flew to the north or south.

???

No citation given, does this mean anything besides "the writer/editor misunderstands orbital mechanics"?

It's one of those newfangled high velocity rendezvous.

Online Lars-J

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #28 on: 01/03/2018 06:59 PM »
I'm very skeptical of this... Here is a quick image showing the path. (from another thread) Note that it basically already overflies Bimini islands and edges Bahamas proper, not to mention all the disruption to shipping lanes and air traffic out of the Miami/Ft. Lauderdale area while also skimming the Florida coastline. There is a *LOT* of stuff to dodge.

It seems exceedingly optimistic. And that's not even getting into the Cuba overflight issues...
I'm not so skeptical.  Start on the line you drew (155 degrees), then as soon as possible make a right turn and head due south.  On the Atlas launch with TDRS-M, at 40 some miles out it was doing 4700 mph (=2100 m/s in rational units).  Doing a 25 degree turn at that point means the cost is 2100 * (1 - cos(25 degrees)) or about 200 m/s (actually somewhat less, since only the horizontal component needs fixing).   That's certainly not prohibitive.

Now the only island that gets passed over is Cuba, and the rocket is high and fast by then.

Then you might as well go slightly north instead, and then turn left over South/North Carolina and head north right over the continental US. Use that as a litmus test for whether or not you think it would be safe for Cuba.  Because surely if it is safe for Cuba, it would be safe for us?  :)

Offline deruch

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #29 on: 01/03/2018 07:46 PM »
Now the only island that gets passed over is Cuba, and the rocket is high and fast by then.

Then you might as well go slightly north instead, and then turn left over South/North Carolina and head north right over the continental US. Use that as a litmus test for whether or not you think it would be safe for Cuba.  Because surely if it is safe for Cuba, it would be safe for us?  :)
That totally misses the point.  Cuba is narrow in the North/South direction and, of course, population density isn't uniform.  Additionally, there are paths over the island in that direction, and at relevant longitudes, which significantly limit overflight of densely populous areas for most of the distance.  But the most significant part of Lou's statement was that the rocket is going "fast by then".  Meaning that for a failure to drop debris on Cuba it would have to occur during a narrow time band during the mission.  Certainly, this remains a possibility.  History has shown that.  But, for a northbound trajectory over the continental US, this doesn't apply.  Any failure after the point where the IIP crosses onto land would result in debris falling on either US or Canadian territory.  Plus the overflight would be over many more areas of higher population density in the eastern US.

http://sedac.ciesin.columbia.edu/data/set/grump-v1-population-density/maps?facets=region:north%20america
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Offline LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #30 on: 01/03/2018 07:58 PM »
Then you might as well go slightly north instead, and then turn left over South/North Carolina and head north right over the continental US. Use that as a litmus test for whether or not you think it would be safe for Cuba.  Because surely if it is safe for Cuba, it would be safe for us?  :)

Precisely this has been done.  See STS-36, which reached 62 degrees where 57 is the normal maximum.  Take off as north as possible, make a left turn, go over North Carolina, then Cape Cod, then Canada.

Offline envy887

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #31 on: 01/03/2018 08:53 PM »
Then you might as well go slightly north instead, and then turn left over South/North Carolina and head north right over the continental US. Use that as a litmus test for whether or not you think it would be safe for Cuba.  Because surely if it is safe for Cuba, it would be safe for us?  :)

Precisely this has been done.  See STS-36, which reached 62 degrees where 57 is the normal maximum.  Take off as north as possible, make a left turn, go over North Carolina, then Cape Cod, then Canada.

62 degrees is a long ways away from sun-sync or polar, neither of which are realistically achievable by launching north. Even if they fly far enough east before the dogleg that the main stage falls in the ocean, there would be several minutes of flight where a failure would drop on populated areas, vs a few seconds at most to the south.

Flying to sun-sunc to the south, the IIP trace crosses only ~70 miles of Cuba and another ~55 miles of Panama, the rest is ocean.

Offline LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #32 on: 01/03/2018 09:10 PM »
Then you might as well go slightly north instead, and then turn left over South/North Carolina and head north right over the continental US. Use that as a litmus test for whether or not you think it would be safe for Cuba.  Because surely if it is safe for Cuba, it would be safe for us?  :)
Precisely this has been done.  See STS-36, which reached 62 degrees where 57 is the normal maximum.  Take off as north as possible, make a left turn, go over North Carolina, then Cape Cod, then Canada.
62 degrees is a long ways away from sun-sync or polar, neither of which are realistically achievable by launching north. Even if they fly far enough east before the dogleg that the main stage falls in the ocean, there would be several minutes of flight where a failure would drop on populated areas, vs a few seconds at most to the south.

Flying to sun-sunc to the south, the IIP trace crosses only ~70 miles of Cuba and another ~55 miles of Panama, the rest is ocean.
I was not suggesting to get to sun-sync by flying North, which is indeed much worse by going North than going South.   I was just noting that to get to orbits that are not "natural" for CCAFS, historically it's been OK to fly over at least some land.  Cape Hatteras, Cape Cod, and eastern Canada are not heavily populated, so the impact odds, times the population density,  gives a small enough number of people killed on the average.

Offline mrhuggy

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #33 on: 01/03/2018 09:36 PM »
I would see as this track would be a non starter, however there is another east coast luanch site which would be more sutible for south bound tracks and thats Wallops. However a overflight of Cape Hatteress would be needed but theres only population in small parts of the track.

Offline RDoc

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #34 on: 01/03/2018 10:09 PM »
Isn't this analogous to N Korea overflying Japan? Tokyo has talked about attempting to shoot down overflying rockets.


Offline woods170

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #35 on: 01/04/2018 06:29 AM »
Isn't this analogous to N Korea overflying Japan? Tokyo has talked about attempting to shoot down overflying rockets.


Major difference between rockets carrying non-weapon payloads and rockets capable of carrying nuclear warheads.
The former is the subject of this thread. The latter is what North Korea has been doing.

Offline kevin-rf

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #36 on: 01/04/2018 01:59 PM »
Isn't this analogous to N Korea overflying Japan? Tokyo has talked about attempting to shoot down overflying rockets.

Well, if the next North Carolina budget has funds for a THAAD system, we will know Polar from Wallops is a non-starter ;)
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Offline nacnud

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #37 on: 01/04/2018 02:30 PM »
Missiles being tested don't carry live warheads.

True, well hopefully true. But how do you tell the difference between an unannounced missile test and an attack?

I think that in the case of overflying Cuba then there will be at least some dialogue between the various parties.

Online Comga

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #38 on: 01/04/2018 04:58 PM »
Quote from: James Dean
“They crunched numbers for about eight months, and I am confident we can go south,” said Monteith (Brig. Gen. Wayne Monteith, commander of the 45th Space Wing)

Monteith did not detail the precise trajectory, but said it involved “a little jog shortly off the pad” to turn south once offshore, “and then we’d skirt Miami.”

The rocket’s first stage would drop safely before reaching Cuba, he said. The second stage would be so high up by the time it flew over the island that no special permissions would be required.

Here's a possible interpretation of his description of the trajectory including "we'd skirt Miami."
It flies over the center of Cuba and might require briefly shutting down Miami, Ft Lauderdale, and West Palm Beach Airports.
But it would be a great show from the Gold Coast, including Mar a Lago ;) 
Actually flying this would really surprise me.

edit:  That path looks a lot like the one Ed Kyle found, but with an earlier turn.
« Last Edit: 01/04/2018 05:08 PM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Newton_V

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #39 on: 01/04/2018 05:21 PM »
The IIP trace can be "easily" steered to fly over sparsely populated areas of west/central Cuba and western Panama.  The dwell time is not long.  Location of jettisoned items like SRBs, stages, and PLF can also be controlled by lofting and/or timing of dogleg maneuver.

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