SpaceX Falcon 9 : PAZ & Microsat 2a/2b : SLC-4E : Feb 22, 2018 : DISCUSSION

[rfoshaug]

I wonder if I observed one of the satellites from Northern Norway(!).

At 18:10 local time (173 minutes after the launch of the Falcon 9), I observed an object that appeared to be venting propellants or thrusting, moving from southwest to northwest. My brother also observed it from about 70 kilometers away. It was clearly in vacuum or near vacuum due to the pure arcing shape of the plumes. As it moved further north it seemed to change from plumes going straight up and down from the object to one big plume to the right of the object as it moved. So it looked almost like a plane change maneuvre.

Now, the reason why I ask if it might be Paz or one of the other payloads is the math. Wikipedia says 514 km altitude for Pez, which gives an orbital period of almost 95 minutes. So when I observed the object, it would be about 1,8 orbits into the flight.

I live at 69° northern latitude. Vandenberg is at 34°, and the launch headed south (at 97° inclination and not 90°, so forgive my naive calculation). So it headed south 34° to equator, 90° to the south pole, 90° north to equator again and 69° north to where I live. That's (34+90+90+69)=283° to travel around the world from Vandenberg to here. That equals (283/360)=0,79 orbits. So yes, the timing would match about 1,8 orbits into the mission, not accounting for the few minutes it takes for the rocket to reach orbital speed, although my observation at 18:10 was when it appeared south of me, not quite at my latitude yet.

My observation was after sunset with a not-quite dark sky, so the satellite I observed roughly followed the terminator with the sun on its left relative to its direction. Paz launched in the very early morning in California, following roughly the terminator with the Sun to its left.

Does anyone know if any of the satellites did a burn or venting of propellants about 173 minutes after launch time?

Edit: also, Vandenberg is 120° west. That means that in a naive calculation it would go up from antarctica at 60° east. But the Earth rotates, and 173 minutes is about 0,12 days. This means the Earth had time to rotate (360°*0,12)=43°, which means the satellite would be over (60-43)=17 degrees eastern longitude. And hey presto, I live at 18° eastern longitude and observed it fly by from southwest to northwest!

Edit 2: the exact directions were difficult to assess as I stopped my car in the middle of nowhere and so I am not positive that it was west of me. But the calculations are so rough that one should not interpret them as precise in any way, just a back-of-the-napkin ballpark calculation.

[Eagandale4114]

I wonder if I observed one of the satellites from Northern Norway(!).

At 18:10 local time (173 minutes after the launch of the Falcon 9), I observed an object that appeared to be venting propellants or thrusting, moving from southwest to northwest. My brother also observed it from about 70 kilometers away. It was clearly in vacuum or near vacuum due to the pure arcing shape of the plumes. As it moved further north it seemed to change from plumes going straight up and down from the object to one big plume to the right of the object as it moved. So it looked almost like a plane change maneuvre.

Now, the reason why I ask if it might be Paz or one of the other payloads is the math. Wikipedia says 514 km altitude for Pez, which gives an orbital period of almost 95 minutes. So when I observed the object, it would be about 1,8 orbits into the flight.

I live at 69° northern latitude. Vandenberg is at 34°, and the launch headed south (at 97° inclination and not 90°, so forgive my naive calculation). So it headed south 34° to equator, 90° to the south pole, 90° north to equator again and 69° north to where I live. That's (34+90+90+69)=283° to travel around the world from Vandenberg to here. That equals (283/360)=0,79 orbits. So yes, the timing would match about 1,8 orbits into the mission, not accounting for the few minutes it takes for the rocket to reach orbital speed, although my observation at 18:10 was when it appeared south of me, not quite at my latitude yet.

My observation was after sunset with a not-quite dark sky, so the satellite I observed roughly followed the terminator with the sun on its left relative to its direction. Paz launched in the very early morning in California, following roughly the terminator with the Sun to its left.

Does anyone know if any of the satellites did a burn or venting of propellants about 173 minutes after launch time?

Edit: also, Vandenberg is 120° west. That means that in a naive calculation it would go up from antarctica at 60° east. But the Earth rotates, and 173 minutes is about 0,12 days. This means the Earth had time to rotate (360°*0,12)=43°, which means the satellite would be over (60-43)=17 degrees eastern longitude. And hey presto, I live at 18° eastern longitude and observed it fly by from southwest to northwest!

That might be the S2 de orbit burn.

[rfoshaug]

Yes, I wondered why any of the satellites would do any major burns at that time. So the question becomes when the S2 deorbit burn took place? If it matches the timing, then that is probably it!

[rfoshaug]

Or if not the deorbit itself, maybe it was venting? But it did not appear to be rotating at all, as the plumes were very straight and had no spiral shape.

[biosehnsucht]

EXCELLENT pic of GO something at speed with nets deployed

https://www.instagram.com/p/BfgHKDNAplx/ (from Elon's tweet)

It's probably not at speed, based on how the water jets are being partially redirected foward by the reverser. My guess is maneuvering (apparently, because turn rate is based on flow rate and not speed in the water, engaging the reverser partially can let you crank up the flow rate for faster maneuvering), backing up (though reverser doesn't seem to be wholly engaged, some water is being jetted out the back normally it appears), or slowing down / transitioning from forward to reverse (or vice-versa).

[John Alan]

EXCELLENT pic of GO something at speed with nets deployed

https://www.instagram.com/p/BfgHKDNAplx/ (from Elon's tweet)

It's probably not at speed, based on how the water jets are being partially redirected foward by the reverser. My guess is maneuvering (apparently, because turn rate is based on flow rate and not speed in the water, engaging the reverser partially can let you crank up the flow rate for faster maneuvering), backing up (though reverser doesn't seem to be wholly engaged, some water is being jetted out the back normally it appears), or slowing down / transitioning from forward to reverse (or vice-versa).

One nice thing about having four water jets on a boat...
IS you can burn a lot of diesel and go nowhere in a hurry... 
I agree that looks staged... Outside jet pair in reverse and inside pair in forward... 

On edit... and yes I know the reverse buckets are fully variable F to R... and maybe in play here...
Bottom line is 4 big CATS tied to 4 decent waterjets can make lots of foam, and not go anywhere if you want them to... 

[cscott]

You're forgetting that somebody had to take the picture.

Most likely they launched the SpaceX drone and Mr. Steven engaged dynamic positioning to hold in place while the drone went out, snapped its pics, and was recovered.

Both the drone and Mr. Steven are capable of navigating to/holding at a fixed GPS position.

In fact, you can see the drone operator on deck, dressed in black.

[Helodriver]

Here are a few still shots from Oxnard this morning.  Some nice plumes at staging and later on some steering jets on the fairings.  At 15 minutes before local sunrise, the sky was already bright enough to wash out an attempted time exposure.

That last photo seems to show both fairing halves manuveuring!

EDIT: Helodriver agrees:

Puffing jets could be seen from BOTH fairing halves, but more from one than the other.

My video of the launch: https://forum.nasaspaceflight.com/downloads/l2/PAZ%20Launch.mp4

Fairing RCS jets start at 3:20 in the video both halves can be seen jetting.

2nd stage at left, fairings middle, 1st stage at right.

[RocketLover0119]

From facts given, I would say the testing put on the S1 post sep was to see if and how long it could survive re entry without burning the engines.

[sevenperforce]

From facts given, I would say the testing put on the S1 post sep was to see if and how long it could survive re entry without burning the engines.

That was my initial guess as well.

Or they just said "to hell with it; we're not reusing these grid fins anyway so there's no reason to expend the labor cost of pulling them off".

If they were, in fact, the originals. Does anyone have a closeup showing whether they were new fins or pre-toasted ones?

[sevenperforce]

If you look at 19:49 in the hosted webcast, you can spot S1 puffing with cold gas thrusters, just for a split second before the view switches. So it clearly was reorienting for entry.

Didn't get many good closeups of S1 during the webcast but from what I could see, they did look like new fins.

[Lostmojo]

Maybe it was observed before, but to me it was the first time to see that the launch control screen behind the host has octaweb engine status indicator turning from green(ahead of launch) to grey(after stage sep).

[Flying Beaver]

Whoopsies posted this in the Cassiope thread originally  .

Was looking at the official SpaceX pictures (among public ones) and noticed a slight dog-leg early in the ascent. Would this of been to avoid a overflight of SLC-6? Seems like a logical explanation.

[Lars-J]

Whoopsies posted this in the Cassiope thread originally  .

Was looking at the official SpaceX pictures (among public ones) and noticed a slight dog-leg early in the ascent. Would this of been to avoid a overflight of SLC-6? Seems like a logical explanation.

It does look like a slight dog-leg, but shouldn't it be in the other direction then? SLC-6 is to the left (not right) in the image.

[webdan]

Don't know if this was posted... too much news today:

https://www.reddit.com/r/space/comments/7zh4l4/i_got_to_see_spacex_falcon9_launch_with_the/

Edit: Typos

[Flying Beaver]

Whoopsies posted this in the Cassiope thread originally  .

Was looking at the official SpaceX pictures (among public ones) and noticed a slight dog-leg early in the ascent. Would this of been to avoid a overflight of SLC-6? Seems like a logical explanation.

It does look like a slight dog-leg, but shouldn't it be in the other direction then? SLC-6 is to the left (not right) in the image.

SLC-4E on right, closer, SLC-6 to left.

Edit: Added a annotated Google Earth overly from the perspective of the photographer.

[overby]

I'm curious: why a sun-synchronous orbit for a RADAR satellite?

Glen

[wannamoonbase]

Don't know if this was posted... too much news today:

https://www.reddit.com/r/space/comments/7zh4l4/i_got_to_see_spacex_falcon9_launch_with_the/

Edit: Typos

That is a fantastic video.  Thank you.

[Machdiamond]

I'm curious: why a sun-synchronous orbit for a RADAR satellite?

It is synchronous on the dawn-dusk boundary, so the solar panels are continuously exposed to sunlight and batteries are not needed to power the radar.

[georgegassaway]

How did the fairing recovery go?

Just sit right back and you'll hear a tale, a tale of a fateful trip....



photoshopped by me

Admittedly, Gilligan is way out of proportion to the size of the fairing. The fairing is about three Gilligans across  (Bob Denver was 5' 8"). But if his image was THAT small, he'd not be as recognizable. Artistic license.     Also the fairing is longer, and probably wider, than the "S.S. Minnow".