Falcon Heavy Test Flight

[Apollo 957]

Congratulations to SpaceX and their FH, recovering both boosters and the center core, then delivering the paid spacecraft into geo stationary orbit.

This.

Seriously impressed. The FH test flight was still a creditable "two out of three ain't bad", though...

[bknight]

Congratulations to SpaceX and their FH, recovering both boosters and the center core, then delivering the paid spacecraft into geo stationary orbit.

This.

Seriously impressed. The FH test flight was still a creditable "two out of three ain't bad", though...

I heard on CQ that they also recovered both fairing halves, but I can't confirm that SpaceX web site isn't too helpful.

[Zakalwe]

Congratulations to SpaceX and their FH, recovering both boosters and the center core, then delivering the paid spacecraft into geo stationary orbit.

This.

Seriously impressed. The FH test flight was still a creditable "two out of three ain't bad", though...

I heard on CQ that they also recovered both fairing halves, but I can't confirm that SpaceX web site isn't too helpful.

It was on Teslarati.com earlier. They didn't use the Mr. Steven boat, but let them land in the sea. Looks like SpaceX have found a way to protect against saltwater exposure. They'll reuse the fairings in a Starling launch later.

[bknight]

Congratulations to SpaceX and their FH, recovering both boosters and the center core, then delivering the paid spacecraft into geo stationary orbit.

This.

Seriously impressed. The FH test flight was still a creditable "two out of three ain't bad", though...

I heard on CQ that they also recovered both fairing halves, but I can't confirm that SpaceX web site isn't too helpful.

The person CQ, admits it was a mistake.  No recovery was attempted as Zakalwe posted.

[smartcooky]

Here are the two fairing halves on the recovery boat.

Note the silvery material on the tip. I've never seen that before.... heat shielding?

[bknight]

Here are the two fairing halves on the recovery boat.

Note the silvery material on the tip. I've never seen that before.... heat shielding?

Don't know what the silvery stuff is, but you are correct.
https://www.universetoday.com/141972/spacex-does-it-again-with-second-retrieval-of-falcon-heavy-rocket/
See Tweet fron Elan about half way down.

[smartcooky]

OK, so back to one of my original questions.

SpaceX say that the landing of the centre core is more "challenging" than a normal F9 downrange landing.

The only thing I can think of that would make this so, is that because it continues to burn for a minute two more, it attains a higher velocity, so in order to land, its re-entry energy will be higher. The side boosters effectively reverse direction with the boostback burn (well actually, they continue to climb and perform a 3/4 loop), but as far as I could tell, there were no additional burns for the centre core. It thumps along at whatever velocity it was doing at MECO, and gathers speed as it falls back to earth, and only performed the single entry burn,

Is this all there is to it, or are there other factors that make it more challenging?

ETA: I just found some interesting figures on a reddit post

https://www.reddit.com/r/spacex/comments/bcdss4/some_meco_and_beco_speeds/

FH Block 5 Arabsat 6A
Booster Engine Cutoff (BECO) 5,800 km/h
Main Engine Cutoof (MECO) 10,730 km/h

Holy Crapola - and it would only get faster as it falls back to earth

I think this probably answers my question.

[ka9q]

It loses a lot to the atmosphere; an empty, light rocket booster apparently makes a good parachute.

But there are limits. I think of the entry burn as a "landing on the atmosphere", necessary to keep the stage from breaking apart as the air gets exponentially thicker. I'm sure this has been analyzed to death, as you don't want to spend any more delta-V on this than absolutely necessary to keep the stage intact.

[Peter B]

ETA: I just found some interesting figures on a reddit post

https://www.reddit.com/r/spacex/comments/bcdss4/some_meco_and_beco_speeds/

FH Block 5 Arabsat 6A
Booster Engine Cutoff (BECO) 5,800 km/h
Main Engine Cutoof (MECO) 10,730 km/h

Holy Crapola - and it would only get faster as it falls back to earth

I think this probably answers my question.

Just for comparison, on the FH Test Flight in 2018, the comparative figures were:

BECO: roughly 6850 km/h
MECO: roughly 9500 km/h

That means the core booster remained throttled up for longer while the boosters were attached (compared to the latest launch), doesn't it? Or the boosters were throttled down for longer?

[JayUtah]

Yeah, typically an unfilled, unpressurized stage fuselage is fairly susceptible to bending moments, but I haven't seen any figures for the F9.  And I don't know what precise aerodynamic loads SpaceX is most worried about.

[ka9q]

I assume the stage is kept fully pressurized, since it still has to perform an landing burn. But even with the entry burn, you do see a lot of shaking as the stage falls into the lower atmosphere.

[Peter B]

For an interesting comparison, I just watched a couple of videos of the launch and landing of the side boosters simultaneously. One was the official SpaceX broadcast while the other was a video recorded by a visitor at the Cape, who was able to keep the boosters in view for their entire flight (search with "Falcon Heavy Launch and Landing - Nikon P1000"). With my amateur efforts I had the two videos synched to within about a second.

Fascinating to compare the views from the boosters with the view of the boosters from the ground.

[Peter B]

A quick question about the booster separation, please.

How are the boosters connected to the core stage, and how does separation occur? The reason I ask is that, watching the video, the separation process seems to take about two seconds. Initially the boosters seemed to push upwards relative to the core stage for about a second, pause, and then peel away.

Is that what happened or did my eyes deceive me?

[Dalhousie]

Unlike this stunt, Apollo 13 was actually inspiring

A stunt? Really?

Its sad that you feel that way.

Would you have preferred they launch a slab of concrete instead, or perhaps risk someone's multi-million dollar satellite on a test flight that could have blown up on the launch pad?

Yes, because it would have actually done something useful. SpaceX/Musk had at least years to develop a useful payload.  There are many possibilities.  Is launching a car really the best they could have come with?

There have been 20 first launches in the past 30 years.  Only one (Angara) carried a mass simulator.  The rest, with the exception of the car stunt, carried useful functioning - satellites (Delta 2, Pegasus,  PLSV, Minotaur C, H-2, Ariane 5, GLSV, Delta IV,  KZ 1, F-1,  Long March 5, Electron, ZQ-1, OS-1B ), boilerplate spacecraft (F-5), or both (Antares, LM-5).  Even the previous first SpaceX launches carried useful payloads.

Of the 20 launches seven (35%) were failures.  This did not stop the launching entities maximising the launch opportunities

[Dalhousie]

Unlike this stunt, Apollo 13 was actually inspiring

A stunt? Really?

Its sad that you feel that way.

It's more sad that people idolise point less stunts

Plus, the huge amount of publicity has helped inspire a lot of young people to think about their futures as being in space, science and technology, which is definitely a good outcome, whatever you might think about the "stunt" aspect of launching a car.

It seems to have worn off.  People are more inspired by actual achievements.

(Anyway, I thought it was cool and fun  )

You can think what you like of it, but when a rich narcissist builds the world's largest rocket and then, after 13 years or more to prepare for it, all he puts into orbit is a surplus car then yes, I call it a stunt.