Author Topic: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION  (Read 219216 times)

Offline spacenut

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #220 on: 04/27/2017 06:00 PM »
Got my days mixed up, thought Saturday was the 30th.  Yes, Sunday Morning.  So the live feed should be on by 7AM Eastern Sunday morning or a little earlier.

Offline BabaORileyUSA

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #221 on: 04/27/2017 06:01 PM »
The inclination of the second stage NOTAM should indicate a dogleg during launch. Can someone check that?

A dog-leg would be a rather silly waste of fuel, since the vehicle *could* launch directly into an orbit with an inclination between 57 and 62 degrees, if a higher inclination were desired.

Offline Jarnis

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #222 on: 04/27/2017 06:05 PM »
Got my days mixed up, thought Saturday was the 30th.  Yes, Sunday Morning.  So the live feed should be on by 7AM Eastern Sunday morning or a little earlier.

20 min prior, and usually launches aim to the beginning of the window.

Of course they may retarget the T-0 Sunday morning and that may cause webcast to start later. Follow the mission update thread here after 6:40 AM local if the webcast is not up then.

Offline Newton_V

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #223 on: 04/27/2017 06:05 PM »
The inclination of the second stage NOTAM should indicate a dogleg during launch. Can someone check that?

A dog-leg would be a rather silly waste of fuel, since the vehicle *could* launch directly into an orbit with an inclination between 57 and 62 degrees, if a higher inclination were desired.

There could be issues with the IIP trace going over Newfoundland.   It can (has) been done, but makes Flight Safety issues easier to avoid to just fly a dogleg, especially if you have a lot of excess performance.

Offline satwatcher

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #224 on: 04/27/2017 08:34 PM »
Note that both the launch and de-orbit hazard areas are consistent with an orbit inclined at 50 degrees. This argues against the use of a dogleg maneuver to target higher inclinations.

Offline kevin-rf

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #225 on: 04/27/2017 09:11 PM »
Besides GPS, what goes to 50 degrees?



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Offline sevenperforce

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #226 on: 04/27/2017 09:15 PM »
I wonder if they will wipe the speed indicators from webcast. The speedometer readily provides acceleration, which in turn provides a pretty good estimate of payload mass.

Offline Newton_V

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #227 on: 04/27/2017 09:25 PM »
I wonder if they will wipe the speed indicators from webcast. The speedometer readily provides acceleration, which in turn provides a pretty good estimate of payload mass.

Only if you know the second stage dry mass, and fluid masses at engine cutoff.  There are way too many unknowns to back out payload mass.  Nevertheless, all data will be cutoff before PLF jettison.

Offline ZachS09

Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #228 on: 04/27/2017 09:28 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.
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Online IanThePineapple

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #229 on: 04/27/2017 09:38 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

This HAS to be LEO, or they're messing with us.
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Online André Carmel

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #230 on: 04/27/2017 09:48 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

Max-Q also happens sooner than ever, maybe this is the first block 4 core, with higher trust. If I remember correctly this core did a full duration burn at Mcgregor. I don't recall if anyone ever gave a good explanation for the longer burn.
« Last Edit: 04/27/2017 09:49 PM by André Carmel »

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #231 on: 04/27/2017 09:52 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

Max-Q also happens sooner than ever, maybe this is the first block 4 core, with higher trust. If I remember correctly this core did a full duration burn at Mcgregor. I don't recall if anyone ever gave a good explanation for the longer burn.

Or the sat could be extremely light, or maybe even both.
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Offline Comga

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #232 on: 04/27/2017 11:18 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

Max-Q also happens sooner than ever, maybe this is the first block 4 core, with higher trust. If I remember correctly this core did a full duration burn at Mcgregor. I don't recall if anyone ever gave a good explanation for the longer burn.

Or the sat could be extremely light, or maybe even both.

The impact of spacecraft mass on the tie of Max-Q has to be very small, while a change in total thrust has a very large impact.  Higher thrust means higher acceleration means higher velocity at a given altitude and going supersonic in denser air. 
Our skilled contributors can verify this or dispute it quantitatively.
« Last Edit: 04/27/2017 11:19 PM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Skyrocket

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #233 on: 04/27/2017 11:40 PM »
This all (inclusive the the Lewis and Clark logo) makes me think of a pretty small area surveillance payload, perhaps something comparable to FORMOSAT-5. Although i would expect a sunsynchronous orbit for this. Or a small SAR area surveillance satellite.

Offline speedevil

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #234 on: 04/27/2017 11:47 PM »
...but per NRO request, live commentary and tracking of 2nd stage will cutoff at payload fairing jettison.  Live feed will then transition to discuss only the first stage as it attempts an RTLS landing back at CCAFS.

Is there going to be a post-launch press conference, with someone from spacex, and a sheet of paper saying 'no comment' on the NRO side?

Offline Jcc

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #235 on: 04/27/2017 11:52 PM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

Max-Q also happens sooner than ever, maybe this is the first block 4 core, with higher trust. If I remember correctly this core did a full duration burn at Mcgregor. I don't recall if anyone ever gave a good explanation for the longer burn.

Or the sat could be extremely light, or maybe even both.

The impact of spacecraft mass on the tie of Max-Q has to be very small, while a change in total thrust has a very large impact.  Higher thrust means higher acceleration means higher velocity at a given altitude and going supersonic in denser air. 
Our skilled contributors can verify this or dispute it quantitatively.

Faster acceleration and earlier MECO means less gravity loss, sooner boost back and less downrange distance to make up. The fuel saving should more than make up for higher friction at Max-Q.

Offline envy887

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #236 on: 04/28/2017 01:29 AM »
Just looked at the NROL-76 press kit.

The MECO time is, to my knowledge, the earliest for a Falcon 9 mission. 2 minutes and 17 seconds after launch. This gives the first stage more fuel than the CRS-9, CRS-10, and Orbcomm-2 flights.

Max-Q also happens sooner than ever, maybe this is the first block 4 core, with higher trust. If I remember correctly this core did a full duration burn at Mcgregor. I don't recall if anyone ever gave a good explanation for the longer burn.

Or the sat could be extremely light, or maybe even both.

The impact of spacecraft mass on the tie of Max-Q has to be very small, while a change in total thrust has a very large impact.  Higher thrust means higher acceleration means higher velocity at a given altitude and going supersonic in denser air. 
Our skilled contributors can verify this or dispute it quantitatively.

Faster acceleration and earlier MECO means less gravity loss, sooner boost back and less downrange distance to make up. The fuel saving should more than make up for higher friction at Max-Q.

Aerodynamic drag has a fairly small effect on fuel burn, but earlier Max-Q could have higher dynamic structural loads. The altitude and velocity data from previous flights show clear throttling through transsonic - but not at Max-Q, so it seems Falcon 9 has some structural margins to allow for more acceleration.

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #237 on: 04/28/2017 06:17 AM »
Could this be a NRO validation flight? So no real payload but some dummy satellite. The purpose would be to establish and validate all the NRO requirements on SpaceX. Can SpaceX actually guarantee the secrecy required for an NRO mission or is there some leak?

Offline Jarnis

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #238 on: 04/28/2017 07:03 AM »
Could this be a NRO validation flight? So no real payload but some dummy satellite. The purpose would be to establish and validate all the NRO requirements on SpaceX. Can SpaceX actually guarantee the secrecy required for an NRO mission or is there some leak?

I doubt even NRO has the money to just send up a dummy payload.

An experimental payload - high risk, low price - is far more likely. So, a real payload but something that doesn't matter that much if something goes wrong (or leaks). Checking out SpaceX procedures "for reals" in preparation of future missions? Maybe a secondary objective.


Offline Star One

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Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #239 on: 04/28/2017 07:30 AM »
Could this be a NRO validation flight? So no real payload but some dummy satellite. The purpose would be to establish and validate all the NRO requirements on SpaceX. Can SpaceX actually guarantee the secrecy required for an NRO mission or is there some leak?

I doubt even NRO has the money to just send up a dummy payload.

An experimental payload - high risk, low price - is far more likely. So, a real payload but something that doesn't matter that much if something goes wrong (or leaks). Checking out SpaceX procedures "for reals" in preparation of future missions? Maybe a secondary objective.
I very much doubt that leaks on even an experimental payload would be tolerated.

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