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

[Ictogan]

For all of the "fun" the roadster might as well be any inert mass. A ground car is helpless in space. Nothing will work on it and this includes the radio. I would of been more impressed if a dragon capsule would of been launched. As soon as the 2nd stage battery packs are spent it is all over. As for Heavy Metal is is a cartoon from the 70's.

Dragon would have been more expensive. A payload for a test launch like this should be something that could go up in flames without causing a big loss to anyone.

[Norm38]

So the center core ran out of igniter or prop?  The former is surprising given the number of landings. The later means they pushed the envelope just a bit too far.

[AUricle]

You can actually spot a part of the center core landing leg going into the drink at 38h:34m into the web cast. I'm quite sure.

How did you get that shot? No matter what playback speed I use, and trying to advance frames at the smallest increments possible, I don't see that through the steam/smoke. When I try to advance it looks like I'm moving 5 frames at a time forwards or backwards. Is there a way to advance just 1 frame at a time?

Furiously pressing the space bar worked flawlessly, as I was quite sure I noticed something. No fancy software or downloading required.

Ok. I see that toggles the start / stop. I found frame by frame is controlled by the "."(forward) and "," (back)

Interesting thing is a couple frames before your dark object shows to the right it is a very brightly lit object in the upper left of the frame! Flys across from L to R

[ginahoy]

Musk quote from the presser: "Nose cone causes loss of control authority." (referring to FH development challenges)

Can someone say more about this?

[drnscr]

For all of the "fun" the roadster might as well be any inert mass. A ground car is helpless in space. Nothing will work on it and this includes the radio. I would of been more impressed if a dragon capsule would of been launched. As soon as the 2nd stage battery packs are spent it is all over. As for Heavy Metal is is a cartoon from the 70's.

They needed to demo the fairing for the Air Force.  Can’t do that with a Dragon on top.

[PeterAlt]

For all of the "fun" the roadster might as well be any inert mass. A ground car is helpless in space. Nothing will work on it and this includes the radio. I would of been more impressed if a dragon capsule would of been launched. As soon as the 2nd stage battery packs are spent it is all over. As for Heavy Metal is is a cartoon from the 70's.

So, how long will it stay attached to the second stage? If it’s not attached when it makes the first Mars flyby, we won’t have any of the cool pics of the Roadster against the backdrop of the Martian atmosphere, or will we?

[abaddon]

So, how long will it stay attached to the second stage? If it’s not attached when it makes the first Mars flyby, we won’t have any of the cool pics of the Roadster against the backdrop of the Martian atmosphere, or will we?

It's not flying by Mars and the stage will be long dead by then.

[kevinof]

So the center core ran out of igniter or prop?  The former is surprising given the number of landings. The later means they pushed the envelope just a bit too far.

He said fuel so I guess that's prop.

[Jeff Lerner]

How does the core run out of igniter ??...there are only so many engines to be restarted and they only restart so many times...Spacex has done this many time before and they hadn't run out of igniter...


Does this imply they had a problem restarting a couple of the engnes a number of times on this flight and ran out of,igniter,??

I'm just speculating on how this could happen ??

[1]

Doesn't matter. Now I'm looking forward to the next blooper reel.

[Kabloona]

How does the core run out of igniter ??...there are only so many engines to be restarted and they only restart so many times...Spacex has done this many time before and they hadn't run out of igniter...


Does this imply they had a problem restarting a couple of the engnes a number of times on this flight and ran out of,igniter,??

I'm just speculating on how this could happen ??

It's unlikely, for the reasons you stated. Each restart uses a known quantity of TEA/TEB.

We have, however, seen stages run out of propellant during the landing burn.

[envy887]

Does anyone know if the Tesla Roadster will make a lunar flyby (or at least a closer approach)?

No, nowhere near it.

The Roadster should be flying almost directly at the Moon during the 3rd burn. Unfortunately Earth's gravity will cause about a 90 turn after that burn, and it will go wide left.

[Nomadd]

Musk quote from the presser: "Nose cone causes loss of control authority." (referring to FH development challenges)

Can someone say more about this?

The way the nose cone affects air flow compared to an interstage on an F9 causes the grid fins to be less effective, so they used the newer, bigger fins on the side boosters.

[envy887]

Musk quote from the presser: "Nose cone causes loss of control authority." (referring to FH development challenges)

Can someone say more about this?

That's when flying the boosters backwards after separation.

The nose cone doesn't allow the air flow to separate cleanly off the tail of the booster - the flow hugs that smooth shape, and when it finally does separate it sheds in vortices. This causes sudden changed in pressure on the side of the nose cone, which makes the booster hard to steer. Thus the bigger fins.

The interstage has a sharp corner which allows clean flow separation when flying the center core (or a F9 booster) backwards.

[Kabloona]

Could it be that the vehicle flew "hotter" than expected (simulations only tell you so much, the wind was blowing at altitude, etc.) during the booster/core phase, requiring the core to use up more propellant than expected while trying to aim for OCISLY?  Just a thought.

 - Ed Kyle

Quite possibly. Musk said they were 0.3 sigma off on propellant usage, which might have been enough to run out of props on the landing burn.

[RanulfC]

As for Heavy Metal is is a cartoon from the 70's.

Yep:
http://www.imdb.com/title/tt0082509/

Opening is a Corvette reentry and landing sequence

For all of the "fun" the roadster might as well be any inert mass. A ground car is helpless in space. Nothing will work on it and this includes the radio. I would of been more impressed if a dragon capsule would of been launched. As soon as the 2nd stage battery packs are spent it is all over.

Would have been nice to have a longer-lasting "package" (A "Green Dragon" to Venus for example ) but as noted they needed to demo the fairing among other things which pretty much limited the options available. Really a couple of solar panels and some experiments, (missed an opportunity to get kids involved which I am a bit mad at Elon for) would have been great but on the gripping hand the off-gassing and other issues of the car itself would have precluded some if not most 'useful' stuff.

Good stuff anyway

Randy

[PeterAlt]

So, how long will it stay attached to the second stage? If it’s not attached when it makes the first Mars flyby, we won’t have any of the cool pics of the Roadster against the backdrop of the Martian atmosphere, or will we?

It's not flying by Mars and the stage will be long dead by then.

So, the backdrops of Earth and the sun are the best (and only) celestial backdrops we’ll get?

[Metalskin]

So, how long will it stay attached to the second stage? If it’s not attached when it makes the first Mars flyby, we won’t have any of the cool pics of the Roadster against the backdrop of the Martian atmosphere, or will we?

It's not flying by Mars and the stage will be long dead by then.

So, the backdrops of Earth and the sun are the best (and only) celestial backdrops we’ll get?

I'm pretty sure that in the news conference, Musk said that the batteries are only good for six hours (maybe it was eight). After that, it will be inert. So no ability to take photos with other backdrops, regardless of it;s location.

[CorvusCorax]

Seems to be some kind of fog building up at the base of the windscreen.

Something's condensing on the (likely) cold glass, but if its water, where does it come from? Could be some chemicals gassing out from the dashboard plastics. This stuff isn't space rated, so it likely contaminates the local environment. And without gravity or wind, it stays in the vicinity of where it came from.

Good thing it has the wind screen to condense on instead of the camera lenses

[RanulfC]

The sequence in question, song is "Radar Rider" btw


Randy