Author Topic: Air Force Identifies CCAFS southbound polar launch azimuth  (Read 8590 times)

Offline woods170

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #20 on: 01/02/2018 12:30 PM »
Also: why do you think this is only being considered for vehicles with autonomous flight termination systems?

I thought that's because range isn't set up to track a southbound rocket to do Old School ground-controlled FTS and adding support to that would be Expensive and kinda silly now that AFTS is the state of the art.

Ground-based FTS is a set of personnel monitoring vehicle health by means of telemetry. Only when those folks have clear indications from telemetry that the vehicle is "going south" (pun intended) will they "hit the self-destruct button". But, in most vehicle anomalies this means the vehicle has already begun to disintegrate all by itself before it actually receives the FTS signal.

One of the quoted advantages of AFTS is that it reacts to vehicle anomalies orders of magnitude faster than ground-based FTS.

So, the clear advantage of AFTS is that it is much more likely the vehicle will end up in lotsa small pieces upon hitting an anomaly whereas in the case of ground-based FTS it is much more likely that large pieces of the vehicle will reach the surface intact.
And that is a particularly important aspect when one considers overflying land, such as overflying Cuba on a south-bound trajectory.

Online edkyle99

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #21 on: 01/02/2018 01:58 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
« Last Edit: 01/02/2018 01:58 PM by edkyle99 »

Offline rpapo

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #22 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.
An Apollo fanboy . . . fifty years ago.

Online edkyle99

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #23 on: 01/02/2018 04:17 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.
AFTS would simply break the rocket into pieces if a failure happened when the IIP was over Cuba, which would result in many pieces, some of them heavy, falling onto Cuba.  Obviously, the Air Force has come up with very low odds that any such debris would hit someone, but I bet they shaped the ground track away from more populated areas to make it happen.   

We know parts would land on Cuba under these circumstances, because it has happened before.*

 - Ed Kyle

* (From my L2 Thor images post https://forum.nasaspaceflight.com/index.php?topic=31405.msg1158028#msg1158028):  Thor 283 and Able Star stage AB006 launched from LC 17B with Transit 3A and GRAB 2/SolRad 2/Greb 2 on November 20, 1960.  Things went awry when the main engine shut down early at T+151 seconds, only a few seconds short of its planned cutoff time. The second stage presumably separated and fired, but Range Safety sent a destruct command at T+325 seconds. 

This was one of several early high inclination Cape Canaveral launches with ground tracks that crossed the eastern tip of Cuba.  The practice created an international embarrassment during this launch.  Debris from the second stage fell on eastern Cuba, with one fragment reportedly falling on a farm near Holguin and killing a cow.  Castro called it part of a U.S. plot against Cuba.  Protesters paraded six cows in front of the U.S. Embassy in Havana, paying tribute to the cow as a "victim of an imperialist rocket".  The U.S. Government paid Cuba $2 million compensation for the incident, after demanding return of pieces of the then-secret rocket.  There's an unconfirmed story that after the incident crews painted a cow on the LC 17 blockhouse wall next to the usual Thor images. 
« Last Edit: 01/02/2018 04:30 PM by edkyle99 »

Offline kenny008

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #24 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 #25 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.

Online edkyle99

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #26 on: 01/02/2018 05:19 PM »
And that is where AFTS comes in. All stages of a launcher must be equipped with it.
Parts still fall.  See.
https://forum.nasaspaceflight.com/index.php?topic=44578.msg1766759#msg1766759
« Last Edit: 01/02/2018 05:20 PM by edkyle99 »

Offline deruch

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #27 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 #28 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 »

Online LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #29 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 #30 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 #31 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 #32 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 #33 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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Online LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #34 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 #35 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.

Online LouScheffer

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #36 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 #37 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.
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Offline RDoc

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Re: Air Force Identifies CCAFS southbound polar launch azimuth
« Reply #38 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 #39 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.

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