Author Topic: SpaceX Falcon 9 : GPS III SV04 : SLC-40 : November 5, 2020 (Read 164505 times)

Ken the Bin · « **Reply #60 on:** 09/30/2020 05:03 am »

I just received an NGA update for this launch. (Nothing yet for NROL-44 and I'm about to head off to bed.)

Launch windows apparently start five minutes after the beginning of the warning period and run for 15 minutes.

Quote from: NGA

300449Z SEP 20
NAVAREA IV 936/20(11,12,26).
WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
030138Z TO 030251Z OCT ALTERNATE
040134Z TO 040247Z OCT
IN AREAS BOUND BY:
A. 28-36-24N 080-35-32W, 28-56-00N 080-13-00W,
28-54-00N 080-10-00W, 28-41-00N 080-20-00W,
28-35-00N 080-26-00W, 28-30-34N 080-33-04W.
B. 32-03-00N 077-00-00W, 34-00-00N 075-28-00W,
34-09-00N 074-38-00W, 33-42-00N 074-03-00W,
33-07-00N 074-31-00W, 31-53-00N 076-48-00W.
2. CANCEL NAVAREA IV 931/20.
3. CANCEL THIS MSG 040347Z OCT 20.

Referenced:

Quote from: NGA

290119Z SEP 20
NAVAREA IV 931/20(11,12,26) CORRECTED COPY.
WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
010146Z TO 010259Z OCT ALTERNATE
020142Z TO 020255Z OCT
IN AREAS BOUND BY:
A. 28-36-24N 080-35-32W, 28-56-00N 080-13-00W,
28-54-00N 080-10-00W, 28-41-00N 080-20-00W,
28-35-00N 080-26-00W, 28-30-34N 080-33-04W.
B. 32-03-00N 077-00-00W, 34-00-00N 075-28-00W,
34-09-00N 074-38-00W, 33-42-00N 074-03-00W,
33-07-00N 074-31-00W, 31-53-00N 076-48-00W.
2. CANCEL NAVAREA IV 914/20, 922/20.
3. CANCEL THIS MSG 020355Z OCT 20.

LouScheffer · « **Reply #61 on:** 09/30/2020 01:04 pm »

Quote from: the_other_Doug on 09/30/2020 02:15 am

I know we're 20 years into the 21st century, but I don't think the range can handle a four-hour turnaround, correct?

A *four hour* turnaround?? Are you crazy? Even commercial airplane flights can't do that! Oh, wait....

Big airports launch more than one plane per minute, from multiple runways. The military routinely does salvo take-offs at more than one per second, from a single runway (watch the Blue Angels formation takeoff, for example).

Musk likes to ask "What's the physical limit?" In this case it would be rockets flying in each other's turbulence. Given the speed of sound, this would allow simultaneous takeoffs from pads a few km apart. Or more extremely, you could launch them closer together and have one fly in the other's wake, reducing drag losses. Anyway, at the current rate of one launch per day, we are more than a factor of 100,000 from the physical limits. There is room for improvement here.

drnscr · « **Reply #62 on:** 09/30/2020 01:31 pm »

What has changed from the days of Gemini when the Atlas-Agena would launch ahead of the Titan II-Gemini on the same day, within hours of each other?

sferrin · « **Reply #63 on:** 09/30/2020 02:03 pm »

Quote from: drnscr on 09/30/2020 01:31 pm

What has changed from the days of Gemini when the Atlas-Agena would launch ahead of the Titan II-Gemini on the same day, within hours of each other?

Risk aversion has gone up by several orders of magnitude.

Alexphysics · « **Reply #64 on:** 09/30/2020 02:03 pm »

Back then tracking systems and range safety destruction was far more simple and rules were more loose. All of that made it possible back then to be able to launch rockets faster but as technology has evolved there are now thousands of sensors transmitting telemetry back to the range and a more improved tracking system that now needs more work and things like that. You would think technology would have made things easier but quite the opposite and mainly because of the many things that technology has allowed rockets to do and measure and all that kind of techy stuff. Now with AFTS and some other ground hardware changes technology is finally allowing them a faster cadence.

Lee Jay · « **Reply #65 on:** 09/30/2020 02:05 pm »

Quote from: LouScheffer on 09/30/2020 01:04 pm

Or more extremely, you could launch them closer together and have one fly in the other's wake, reducing drag losses.

I don't think that works on a rocket.

Jansen · « **Reply #66 on:** 09/30/2020 02:27 pm »

Quote from: klod on 09/30/2020 03:15 am

Minimum time between 2 different LV - 17 hours.

New time between NROL-44 and Starlink launches is approximately 9 hours. So it looks like things have improved.

LouScheffer · « **Reply #67 on:** 09/30/2020 02:30 pm »

Quote from: Lee Jay on 09/30/2020 02:05 pm

Quote from: LouScheffer on 09/30/2020 01:04 pm
Or more extremely, you could launch them closer together and have one fly in the other's wake, reducing drag losses.
I don't think that works on a rocket.

Why not? Drag reduction by formation flying offers two ways to reduce drag. One is reduced frontal area, like drafting in bicycles or cars, the other is by using the wing vortex to provide lift and hence reduce induced drag. The second won't work for rockets, but the first should still be available. Supersonic the physics is different, but formation flying can still offer a drag advantage. See Design Space Exploration of Supersonic Formation Flying Focusing on Drag Minimization . Clearly additional study would be warranted once the flight rates get high enough.

EDIT: Returning Falcon heavy side boosters would be a great experimental system for this.

Vettedrmr · « **Reply #68 on:** 09/30/2020 02:54 pm »

It's a purchase item so couldn't read the entire text, but to capture any kind of wave-riding effect the two rockets would have to actually be flying in formation, not just one a few minutes behind the other. You would literally have to launch them simultaneously, have one maneuver into the other's wake, etc. Not to mention different flight paths for different payloads, etc.

Now, as far as quick launches go, I think it's more of a combination of old FTS technology, old procedures, new AFTS tech, new procedures, all trying to work together. I think turnaround times will continue to shrink, but honestly, flight rates aren't anywhere near really needing it. We just have a collision of flights right now.

Have a good one,
Mike

abaddon · « **Reply #69 on:** 09/30/2020 02:56 pm »

Quote from: Alexphysics on 09/30/2020 02:03 pm

Back then tracking systems and range safety destruction was far more simple

Actually, with AFTS, the reverse is arguably true. Unfortunately ULA launchers don't have AFTS yet...

This and the "rocket wake" discussions are fascinating, but have nothing to do with GPS III...

Ken the Bin · « **Reply #70 on:** 09/30/2020 03:06 pm »

L-2 weather forecast:

IntoTheVoid · « **Reply #71 on:** 09/30/2020 04:16 pm »

Quote from: LouScheffer on 09/30/2020 02:30 pm

Quote from: Lee Jay on 09/30/2020 02:05 pm
Quote from: LouScheffer on 09/30/2020 01:04 pm
Or more extremely, you could launch them closer together and have one fly in the other's wake, reducing drag losses.
I don't think that works on a rocket.
Why not? Drag reduction by formation flying offers two ways to reduce drag. One is reduced frontal area, like drafting in bicycles or cars, the other is by using the wing vortex to provide lift and hence reduce induced drag. The second won't work for rockets, but the first should still be available. Supersonic the physics is different, but formation flying can still offer a drag advantage. See Design Space Exploration of Supersonic Formation Flying Focusing on Drag Minimization . Clearly additional study would be warranted once the flight rates get high enough.

EDIT: Returning Falcon heavy side boosters would be a great experimental system for this.

What wake? For and auto or bicycle, and even for a boat, the motive force is not directly behind the vehicle. As the vehicle leaves a location in space a local low pressure area is created that draws air (and possibly drafting vehicles) in. Rockets for the most part, but especially F9, don't do this. They leave an underexpanded (high pressure) volume of exhaust products moving opposite the direction of travel. Traveling in this wake would be harder, not easier.

Even jets don't fly nose to tail. They fly off the wings where there can be favorable aerodynamics. And F9 doesn't have wings.

Jansen · « **Reply #72 on:** 09/30/2020 07:14 pm »

Quote from: Vettedrmr on 09/30/2020 02:54 pm

I think turnaround times will continue to shrink, but honestly, flight rates aren't anywhere near really needing it. We just have a collision of flights right now.

Quick turnaround times are a stated goal of KSC. There are sometimes limited launch opportunities due to weather, mechanical issues, and instantaneous launch windows.

Having a scrubbed launch has a cascade effect on the entire schedule. This will only get worse as the launch tempo increases over the next couple of years.

I am impressed though that turnaround has gone from 36 hours to 9 hours with NRO-44 and Starlink 12. If they hadn’t been making such efforts the GPS launch could’ve possibly been delayed another week.

capoman · « **Reply #73 on:** 09/30/2020 08:28 pm »

Quote from: Jansen on 09/30/2020 07:14 pm

Quote from: Vettedrmr on 09/30/2020 02:54 pm
I think turnaround times will continue to shrink, but honestly, flight rates aren't anywhere near really needing it. We just have a collision of flights right now.

Quick turnaround times are a stated goal of KSC. There are sometimes limited launch opportunities due to weather, mechanical issues, and instantaneous launch windows.

Having a scrubbed launch has a cascade effect on the entire schedule. This will only get worse as the launch tempo increases over the next couple of years.

I am impressed though that turnaround has gone from 36 hours to 9 hours with NRO-44 and Starlink 12. If they hadn’t been making such efforts the GPS launch could’ve possibly been delayed another week.

Yes, these range conflicts appear to be getting much more common this year, especially with the added Starlink flights. Looks like other payloads are picking up as well, so I agree, that launch tempo looks like it will pick up and the range needs to continue to up their game.