SpaceX Falcon 9 : GovSat-1 (SES-16) : Jan 31. 2018 - Discussion

[LouScheffer]

SpaceTrack has not released the transfer orbit, presumably since this is a military mission.  However, using data from the Webcast, we can make a reasonable guess.

From the webcast, we know the delta-V from the parking to transfer orbit was 2636 m/s (26489 km/hr at beginning, 35980 at end).

Next, using the final velocity, then adding in the roughly 400 m/s for the Cape's eastward rotation (we know this is not included, since the velocity is 0 at takeoff) we can figure an apogee of 52000 km.

Now, using the delta-V from parking orbit, we can find the inclination.  As it turns out, they need all 2636 m/s to get from a 250x250 parking orbit to 250x52000.   If they used any of the delta-V for inclination reduction, the final absolute velocity, and the perigee, would be lower.   For example, if they reduced the inclination to 24^o (which would actually be slightly helpful) then the apogee would be lower at 44,000 km, and the final velocity would be 85 km/sec less than shown on the webcast.

So it seems very likely the transfer orbit was 250 x 52000 x 27^o, leaving about 1690 m/s to go to GEO.

[envy887]

Confirmed.  It was destroyed.  There was no safe way to tow it back without risk to land, sea, and people.

Does the Range Officer pressing the FTS terminate button count as the "Air Force carrying out a strike"?

Assuming the AFTS has a manual terminate option, and that it works over the horizon via relay or something.

there is no manual option

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

[whitelancer64]

Confirmed.  It was destroyed.  There was no safe way to tow it back without risk to land, sea, and people.

Does the Range Officer pressing the FTS terminate button count as the "Air Force carrying out a strike"?

Assuming the AFTS has a manual terminate option, and that it works over the horizon via relay or something.

there is no manual option

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

They operate the range equipment - tracking cameras, radars, telemetry receivers, etc.

[Jim]

Confirmed.  It was destroyed.  There was no safe way to tow it back without risk to land, sea, and people.

Does the Range Officer pressing the FTS terminate button count as the "Air Force carrying out a strike"?

Assuming the AFTS has a manual terminate option, and that it works over the horizon via relay or something.

there is no manual option

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

Sea and airspace clearance, Telemetry receiving, launch danger area road blocks, comm, weather, etc

[speedevil]

We now have to hunt for the fighter with a F9 silhouette on it.

Or FOIA for the gun-cam.

[Zed_Noir]

We now have to hunt for the fighter with a F9 silhouette on it.

Not necessary. A jet fighter is not the ideal tool for the job.

My money is on a Spec Ops AC-130 gunship at night. Look for the F9 silhouette on a Spooky.

[Zed_Noir]

IMHO an A-10 sortie would do the trick just fine.  Don’t believe me?  Ask an Iraqi tank crew if you can find one alive.

Not likely. The A-10 is not design for maritime missions.

[ppb]

I would bet a strafing run with the 20mm cannon most Air Force tactical combat aircraft are equipped with would do the job easily and relatively inexpensively, and would still qualify as an “air strike.”

Would have to get pretty low for a strafing run. Seems a risk of frag damage.  A JDAM, Hellfire or some other standoff guided missile would be a safer, albeit more expensive option.

No, it is going to be guns and not missile or bomb.  And no, there is no risk of frag damage, what you do think they are shooting at on a battlefield?

So those exploding boosters on the deck of the ASDS would have posed no risk to low overflying aircraft. OK, if you say so.

[drnscr]

IMHO an A-10 sortie would do the trick just fine.  Don’t believe me?  Ask an Iraqi tank crew if you can find one alive.

Not likely. The A-10 is not design for maritime missions.

A former A-10 pilot friend of mine would beg to differ.  But, in the big picture scheme of things, it doesn’t matter.

Feel the BRRRRRRRRRRRRRRRTTTTTTTT

[deruch]

Likely used helicopter, not fixed wing.

[ugordan]

This thread has really taken a strange turn.

[Nehkara]

SpaceX finally just put up the video for the launch:

[matthewkantar]

Or FOIA for the gun-cam.

I wonder how far away the workboats had to be? They may have footage from a distance.

Matthew

[abaddon]

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

Flipping it around, what's the point of AFTS if the range has to be responsible for it still?

[Paul_G]

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

Flipping it around, what's the point of AFTS if the range has to be responsible for it still?

But the AFTS was 'safed' during landing. Can it be 'unsafed' - especially once it is bobbing around in the sea? You obviously want the safing process to be reliable, and not want the risk of it triggering unintentionally, so once it is 'saved' it is probably safe for good.

Paul

[mn]

What does the range do then, once it launches? What's the point of tracking it if they can't terminate?

Flipping it around, what's the point of AFTS if the range has to be responsible for it still?

Regardless of whether that was possible here (certainly not possible), but as to your question: I would have assumed that AFTS still allowed the range to manually trigger a destruct (in addition to the automatic function). so Jim's assertion that there is no manual control is a surprise to me.

[Grandpa to Two]

I would think the Coast Guard will take care of it. Just tell a Skipper it’s full of drugs, make it go away.

[macpacheco]

I doubt that the Air Force can just shoot at something on behalf of a commercial company, especially in a shipping lane, etc.  The Navy has a testing range off the west coast of Florida, where any such live-fire exercise event is tightly controlled.

On the other hand, which DoD entity is in charge of clearing the shipping lanes of hazards?  Could this be a Coast Guard matter?  Then again, since it is in international waters, maybe no one is really in charge.

I could be wrong.

 - Ed Kyle

The military must operate in due regard to others. Shipping lanes aren't civilian only zones. Its not like dropping a bomb on a freeway. That would be big trouble.
You can blow things in the Ocean surface safety as long as there's no civilian traffic within 10nm or so. And 10nm is a big safety margin. Any tactical fighter has radar capable of distinguishing anything larger than a tiny buoy from ocean. An F16 carrying just 2 500lb bombs is very nimble and able to look around doing 4g turns at low altitude. The dumb bomb is actually quite cheap, but the F16 per hour costs a lot...

The cheapest solution would be SpaceX drags it as near as it safely can to the coast. The NAVY sends one of those little rubber boats with a mini gun. Cheap fuel, cheap ammo. The kind of boat that destroyers carry a bunch of.

But if you really care about ITAR, you don't just want to sink it. You want to blow it to as many pieces as you can. Make the wreckage in the bottom truly useless. Typically uncontrolled re-entry takes care of that and then some. So either use a cannon that has an explosive shell, stick some explosives to the stage or actually drop a bomb on it.

[sewebster]

So... do they go looking for any booster they soft land in the water, just in case? Or are they close enough in the ships to see the explosions or lack thereof?

[aero]

Wouldn't it still have had oxygen in the lox tank? I can't guess how explosive the RP1 and oxygen mixture would have been, I guess it depends on whether or not the lox was vented after touchdown. Anyway, what's the chance of setting it off with just a few explosive shells? Of course with those guns, it's hard to fire just a few rounds. And under the circumstances, what pilot would stop at just a few?