SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[zubenelgenubi]

Could we turn this thread back into updates, please?  Snip, snip? 

I think the horse pony already left the barn. 

(gif animation attached)

[lrk]

Usually when it takes this long to get word the landing was not successful. 

They very clearly called out "we lost the center core" on the stream, if you listen carefully to just after the side cores land. 

[cscott]

Even if the center core is floating in pieces, they can probably fish out enough for an interesting postmortem of welds, etc.

[TomH]

Could also be that the beefing up of the structure was insufficient, or that it altered some characteristics...

Those mods were so it could carry the load stresses. It wass successful from that POV, but yea, wonder if it affected EDL.

[Kabloona]

LZ pic from Elon:

https://www.instagram.com/p/Be3sOnEA0DK/

Aerial ballet.

[spacetraveler]

If the center core didnīt make it (as some people are reporting) it actually just underlines that this was HARD! Too bad about the data they could have gotten from it, but... not important in the big picture.

Really too bad, lost all that wear data on the center core. I wonder why it didn't land, I would've thought that after the entry burn its descent is the same as any GTO mission.

Just because the landing was not successful does not mean all data was lost. It was likely returning telemetry for most of the flight.

[Kabloona]

Second burn was successful. Elon tweeted that apogee was raised to 7000 km, lower than expected for a 6-hour orbit. Is that a 3-hour orbit, and they orbit twice before restart?

[Jeramiah Johnson]

IF the center core did not make it to the ship, my initial stake in the ground is going to be fuel or what ever is used to "steer" the core in. Looking at the still frame, it would suggest the core is slightly off from the ship and that would imply a navigational error. Hence my initial stake in the ground.

[david1971]

Odd thought: We have no idea of the current status of the last two cores headed to the drink.

[Kabloona]

So Elon Musk reports a good second burn, but he said that the apogee was 7,000 km, which I believe is much different that we were expecting/guessing.  Now there will be, Elon says, a 5-hour coast before restart.  Interesting.  I'm not sure yet what that all means.

 - Ed Kyle

Yes, it sounds like multiple orbits before restart.

[spacetraveler]

Elon just tweeted that the 2nd burn was to 7000km apogee, a significant raise but much less than GTO.

Now we wait for the final burn to heliocentric orbit.

[toruonu]

Could this be due to the late in the window launch? That they had to trim the orbit and the coast time?

[Kabloona]

Elon just tweeted that the 2nd burn was to 7000km apogee, a significant raise but much less than GTO.

We didn't expect an actual GTO orbit, rather a 20,000 km apogee that would give a 6-hour orbit, with restart at perigee. But obviously not.

[Nascent Ascent]

Thanks all for answering re D4H.

So....

Take that N1! 3 x 9 = no problem.

[BunkerTheHusky]

My wild speculation is the hush hush on the center core is that it took out the ASDS. Wonder what it would take to sink one if a landing goes awry.

[Space Ghost 1962]

So Elon Musk reports a good second burn, but he said that the apogee was 7,000 km, which I believe is much different that we were expecting/guessing.  Now there will be, Elon says, a 5-hour coast before restart.  Interesting.  I'm not sure yet what that all means.

 - Ed Kyle

Yes, it sounds like multiple orbits before restart.

It also launched later.

If they are keeping with the same target orbit, they'll have to change burns/attitude  to compensate. Perhaps less with second burn to reduce time to next one, as well as a different line of apsides due to earth's rotation.

Then perhaps a longer third burn.

[Kabloona]

My wild speculation is the hush hush on the center core is that it took out the ASDS. Wonder what it would take to sink one if a landing goes awry.

Oh ye of little faith. OCISLY has taken many beatings and kept on ticking.

[Comga]

So Elon Musk reports a good second burn, but he said that the apogee was 7,000 km, which I believe is much different that we were expecting/guessing.  Now there will be, Elon says, a 5-hour coast before restart.  Interesting.  I'm not sure yet what that all means.

 - Ed Kyle

That puts the earth escape burn at perigee, where it is most efficient due to the Oberth effect, but at the end of a coast that's equal to the LEO to Geo coast of a GTO launch.  This demonstrates the extended coast time the Air Force needs to see for direct injection into Geo without putting the escape burn beyond the capabilities of the stage.

This was surmised by JCM many hours ago on the update thread. (Good luck finding it.  Everything is buried in posts.)

[Oersted]

So Elon Musk reports a good second burn, but he said that the apogee was 7,000 km, which I believe is much different that we were expecting/guessing.  Now there will be, Elon says, a 5-hour coast before restart.  Interesting.  I'm not sure yet what that all means.

 - Ed Kyle

Yes, it sounds like multiple orbits before restart.

It also launched later.

If they are keeping with the same target orbit, they'll have to change burns/attitude  to compensate. Perhaps less with second burn to reduce time to next one, as well as a different line of apsides due to earth's rotation.

Then perhaps a longer third burn.

Musk tweeted "upper stage restart nominal" so clearly everything is going according to plan.

[Rocket Science]

Usually when it takes this long to get word the landing was not successful. 

They very clearly called out "we lost the center core" on the stream, if you listen carefully to just after the side cores land.

I only heard they lost the signal, but I was screaming at the time...