SpaceX F9 - 5th Reuse - Iridium Next 31-40 - SLC-4E

[Grendal]

Ah... I misinterpreted your comments to mean fins on the second stage for a recovery experiment there. Thanks.

That is what I was thinking was going on. Once I learned that the grids were not smaller then I had to reevaluate my reasoning. I still think SpaceX is doing something. What that something is, is still unknown. Hopefully we learn something on the webcast.

 

[ecarfan]

Thanks for posting that photo. Very interesting. Why is the interstage a dark color? I thought it was always white like the rest of the rocket. I think SpaceX is trying something new with the 2nd stage. We know that there will be no 1st stage recovery attempt. So those grid fins are there for another purpose. If they weren’t going to use them, they would have been removed, in my opinion, just like the 1st stage legs were removed because they aren’t going to be needed for this mission.

It looks like SpaceX will be doing an experiment on second stage recovery. That is probably why they aren't trying to recover the booster this time. Here is a picture of the rocket at Vandenberg on the pad. You can see the little mini grid fins.
View attachment 268116

 

[ecarfan]

I think the interstage is a different color because it is a different design than in the past.

 

[mongo]

I read that the legs get removed after every flight. Removing fins would leave a hole, and take extra effort.

From reddit, apparently this first stage had titanium grid fins during its last flight, so they purposely changed to aluminum...
So much for that idea...

 

[Grendal]

From reddit, apparently this first stage had titanium grid fins during its last flight, so they purposely changed to aluminum...
So much for that idea...

Good point. There is lots of evidence that SpaceX is trying to do something. What that something is may or may not be explained to us.

Here is the webcast on this page of comments so people can find it easier:

 

[nwdiver]

Why did they leave the gridfins on if they're not going to attempt a recovery?

 

[e-FTW]

Why did they leave the gridfins on if they're not going to attempt a recovery?

Also, why did we hear, at T+7 that the first stage was doing an entry burn?
You can't bouncy castle a first stage....

 

[PV-EV]

Why was I hearing mention of the first stage ‘entry burn’ etc around T+7:30 in the background of the commentary??

 

[Electroman]

I was wondering the same thing and you could actually see the first stage doing boost back from a camera angle from 2nd stage a few seconds after separation

 

[nwdiver]

Also, why did we hear, at T+7 that the first stage was doing an entry burn?
You can't bouncy castle a first stage....

Yeah... that was odd... it DID do a boost back burn... maybe they're doing testing?

 

[Grendal]

Yeah... that was odd... it DID do a boost back burn... maybe they're doing testing?

Definitely doing some sort of testing. What it is seems to be a secret. Some sort of experiment where they did a water landing as if the ASDS was there.

 

[e-FTW]

Yup, most definitely did a boost back burn, as everyone in SoCal saw it clearly...
Leandro Perez on Twitter

 

[mongo]

Definitely doing some sort of testing. What it is seems to be a secret. Some sort of experiment where they did a water landing as if the ASDS was there.

Could be using the standard controlled descent to the water, possibly at/ outside the normal control limits. Testing an engine failure during landing?

It would be more environmentally friendly to land at zero velocity after using all available fuel. Take the engines below the normal minimum thrust to hover followed by turbopump fuel starvation test?

 

[Cosmacelf]

Right at the beginning of the webcast, the guy said they were going to do a first stage controlled ocean landing since there was no drone ship in position.

 

[Grendal]

Could be using the standard controlled descent to the water, possibly at/ outside the normal control limits. Testing an engine failure during landing?

It would be more environmentally friendly to land at zero velocity after using all available fuel. Take the engines below the normal minimum thrust to hover followed by turbopump fuel starvation test?

Exactly. Something like this has happened. Those are some good ideas. You could hear the 1st stage maneuvering commentary in the background of the launch webcast. We could see the boostback burn happen at stage separation.

 

[e-FTW]

Man, that was one short second burn of the second stage engine!

 

[SMAlset]

Nice launch. Enjoyed the liftoff and wish I could have seen it in person. CameronB did you make it down there? Look forward to the photos being posted from people down there. Always nice to see those golden satellites float away. Very successful year for SpaceX.

 

[Grendal]

100% success. I hope SpaceX gets lots of advertising from all the news of UFO's over LA. I expect lots of LA news articles and TV segments explaining.

Lots of "UFO" videos hitting Youtube already:

 

[anticitizen13.7]

John Insprucker always seems to host the “holiday weekend” launch events, haha.

I like his matter-of-fact news anchor style, although I can understand why SpaceX features younger employees on higher profile launch events. These webcasts must make a decent recruiting tool.

 

[e-FTW]

Elon Musk on Twitter