Author Topic: SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2 (Read 597989 times)

andylander · « **Reply #320 on:** 02/05/2018 07:43 pm »

Quote from: ChrisC on 02/05/2018 06:52 pm

Quote from: andylander on 02/05/2018 06:20 pm
Quote from: Chris Bergin on 02/05/2018 05:51 pm
Elon to hold a media event at 3:30 p.m. EST - per an e-mail from SpaceX.

Is there a link to where we can watch or listen to this media event?

Probably not. It'll be for media onsite at KSC. NSF's Chris Gebhardt is there so we'll hear about any new news right way, right here. And all those reporters will then immediately file stories, so you'll read about it within an hour or two. Don't know if reporters are allowed to stream live from the media event.

Thanks for the info and for moving this to the right thread. Sorry for posting a question in the update thread.

It would be awesome if a reporter could Periscope the event, assuming they could clear it with SpaceX.

tvg98 · « **Reply #321 on:** 02/05/2018 07:49 pm »

Quote

Musk: We are doing a six-hour coast to demonstrate to the Air Force the capability to do direct-to-GEO missions. Risk is that the Roadster ends up in LEO.

https://twitter.com/SciGuySpace/status/960615490803634176

Quote

Musk: If the third burn goes as we hope, the Tesla will get as far away as 380 to 450 million km from Earth.

https://twitter.com/SciGuySpace/status/960616514708758529

AC in NC · « **Reply #322 on:** 02/05/2018 07:56 pm »

Quote from: geza on 02/05/2018 07:53 pm

Third burn in what sense?

Sounds like in addition to a profile somewhat analogous to the 1st SECO and 2nd SECO for the GTO orbit, the 3rd burn would be to Mars but would have demonstrated the ability to coast to the point of a 3rd Burn to circularize to GSO.

cebri · « **Reply #323 on:** 02/05/2018 07:58 pm »

Makes sense. Showing important FH capabilities, direct GEO insertion and the ability to perform deep space missions.

envy887 · « **Reply #324 on:** 02/05/2018 07:58 pm »

6 hours in LEO! That puts TMI at 19:30 EST if they launch at the opening of the window, or 4 orbits after launch.

Jarnis · « **Reply #325 on:** 02/05/2018 08:03 pm »

Quote from: envy887 on 02/05/2018 07:58 pm

6 hours in LEO! That puts TMI at 19:30 EST if they launch at the opening of the window, or 4 orbits after launch.

Speculation: Maybe they do a GEO profile and then just burn longer? I know its inefficient, but the mission has hilarious amounts of margin anyway? Ie. Launch, coast to equator, 2nd burn to GTO, 3rd burn at GEO height that just goes way longer than a GEO insertion?

rsdavis9 · « **Reply #326 on:** 02/05/2018 08:04 pm »

Quote from: envy887 on 02/05/2018 07:58 pm

6 hours in LEO! That puts TMI at 19:30 EST if they launch at the opening of the window, or 4 orbits after launch.

I think the 6 hour coast is between 2nd and 3rd burns.

Space Ghost 1962 · « **Reply #327 on:** 02/05/2018 08:05 pm »

Quote from: launchwatcher on 02/05/2018 06:28 pm

Quote from: lrk on 02/05/2018 06:17 pm
There are so many things wrong in that video...

* No FSS?
Musk borrowed some hardware from the Romulans. It stays cloaked until the vehicle clears the tower. See around 0:53 in the video for its first appearance.

It's not the FSS. It's a triangular pylon replacement for it, with a crane on top (can't see a crew access arm).

add:
Or maybe the crane is the crew access arm, hard to tell.

You know, the shape/size/cross-section ... looks like the lower part of the BFR/BFS pylon. As if you'd be able to convert 39A in place to BFR operations by stacking more sections on top ... hmm.

Leave it Musk to hide the beginnings of BFR pad migration ... right in front of our noses ...

toruonu · « **Reply #328 on:** 02/05/2018 08:06 pm »

Any orbit paraneter speculations? If the TMI burn is followed 6h later by 3rd burn how much can they shift the plane to move the final orbit away from earth orbit intersection allowing it millions of years of lifetime...

IanThePineapple · « **Reply #329 on:** 02/05/2018 08:10 pm »

Quote from: toruonu on 02/05/2018 08:06 pm

Any orbit paraneter speculations? If the TMI burn is followed 6h later by 3rd burn how much can they shift the plane to move the final orbit away from earth orbit intersection allowing it millions of years of lifetime...

We might find out soon, there's a press call going on right now or soon

macpacheco · « **Reply #330 on:** 02/05/2018 08:13 pm »

Quote from: Johnnyhinbos on 02/05/2018 07:49 pm

Quote
Musk: We are doing a six-hour coast to demonstrate to the Air Force the capability to do direct-to-GEO missions. Risk is that the Roadster ends up in LEO.

https://twitter.com/SciGuySpace/status/960615490803634176

Quote from: macpacheco on 01/30/2018 07:29 pm

One argument against the direct insertion.
What capability SpaceX would like to demonstrate to customers ?
Long coast.
This is an upper stage feature (common to F9 and FH). So if SpaceX knows it can coast for 3 hours (just a guess), then why not demonstrate it ?
I think people are too obsessed with the Roadster and Mars and missing the big picture.
SpaceX is showing NASA, USAF, NRO, ... what the Falcon family of rockets can do. Its the first opportunity in a long time to show them off.
I'm suggesting this from a strictly business/marking view, technically I have no idea how it would impact the launch window and resulting orbit.

TOLD YA ! 6 hour coast. I said 3 hours, because I had no clue how long a coast it could do.
The key technical goals of this missions aren't to put a cool car on a Mars orbit but to show NASA and USAF that the FH can do as much as DIVH can, that except for payload to Pluto or Jupiter, it actually beats anything ULA can do.
Jim will correct me with something D4H can do better than FH in 10 seconds !

Apollo-phill · « **Reply #331 on:** 02/05/2018 08:15 pm »

Really a double whammy tomorrow evening ( UTC/GMT Time) since not only first Falcon Heavy launch but at 19:58 UTC ,a newly discovered Apollo type asteroid , 2018 CC, will flyby Earth at about half the distance between Earth-Moon. Its estimated size is anywhere from 9 to 30 metres and was only discovered on the 4 February 2018. Its inclination is about 8.6 degrees and its velocity is around 6 km/sec with respect to Earth.

Maybe should call asteroid the " Tesla Roadster Chaser " ?

Wishing Spacex team and its staff all success with first Falcon Heavy launch, hopefully, due tomorrow.

I've waited and watched astronautics since the 50s era and have encouraged our species since that time to explore and utilize space for the benefit of humanity.

I think tomorrow will mark the start of the " coming of age" of spaceflight after the pioneering programs of Russia ( Vostok/MIR/ISS/Luna/Venera) and USA ( Gemini /Apollo /Shuttle /ISS/MER/MSL/Voyager/Cassini,et al).

Are you " ..looking down ." Mr Goddard, Mr Tsiolkovsky, Mr von Braun , Mr Mueller , Mr Clarke , Mr Korolev and all those other dreamers and pioneers to see your aspirations start to mature ? I hope so !

Phill

envy887 · « **Reply #332 on:** 02/05/2018 08:27 pm »

Quote from: Jarnis on 02/05/2018 08:03 pm

Quote from: envy887 on 02/05/2018 07:58 pm
6 hours in LEO! That puts TMI at 19:30 EST if they launch at the opening of the window, or 4 orbits after launch.

Speculation: Maybe they do a GEO profile and then just burn longer? I know its inefficient, but the mission has hilarious amounts of margin anyway? Ie. Launch, coast to equator, 2nd burn to GTO, 3rd burn at GEO height that just goes way longer than a GEO insertion?

There is no risk of remaining in LEO after coast, if the coast is after GTO insertion. See Eric Berger's quote of Musk. Eric knows the difference between LEO and GTO, so the 6 hour coast must be 4 orbits in LEO.

To do a 6 hour coast in LEO and then a burn at GEO distance would require 12+ hours of total endurance, which seems unlikly. More likely Musk is calling S1 ascent the 1st burn, S2 ascent the 2nd burn, and TMI after coast the 3rd burn.

https://twitter.com/SciGuySpace/status/960615490803634176

JonathanD · « **Reply #333 on:** 02/05/2018 08:29 pm »

Does anyone know if the primary concern is RP-1 temp, or battery life? Or both?

Basto · « **Reply #334 on:** 02/05/2018 08:31 pm »

LOX boiloff and batteries.

flyright · « **Reply #335 on:** 02/05/2018 08:32 pm »

Would 6 hour coast mean LOX is no longer densified?

Space Ghost 1962 · « **Reply #336 on:** 02/05/2018 08:38 pm »

Quote from: flyright on 02/05/2018 08:32 pm

Would 6 hour coast mean LOX is no longer densified?

Doesn't matter.

The other two burns (ascent, circularization/plane adjustment/phase/apsides) will consume volume.

Thermal management of the stage, needed for the long life/coast will keep prop temps within the restart "box" of parameters.

envy887 · « **Reply #337 on:** 02/05/2018 08:42 pm »

Quote from: flyright on 02/05/2018 08:32 pm

Would 6 hour coast mean LOX is no longer densified?

If it's boiling off, it's no longer subcooled unless the are venting to vacuum to depress the boiling point and using that to cool the remainder of the propellant. With some assumptions about heat load in LEO that would make an interesting BOTE calc.

flyright · « **Reply #338 on:** 02/05/2018 08:42 pm »

Quote from: Space Ghost 1962 on 02/05/2018 08:38 pm

Quote from: flyright on 02/05/2018 08:32 pm
Would 6 hour coast mean LOX is no longer densified?
Doesn't matter.

The other two burns (ascent, circularization/plane adjustment/phase/apsides) will consume volume.

Thermal management of the stage, needed for the long life/coast will keep prop temps within the restart "box" of parameters.

That was going to be my next question.

Thanks!

speedevil · « **Reply #339 on:** 02/05/2018 08:45 pm »

Quote from: Basto on 02/05/2018 08:31 pm

LOX boiloff and batteries.

I question batteries being an issue if you've got tons of margin, and a ton gets you 200kWh of battery. (yes, it's not quite this simple, and you'd need thermal managment for the battery).

Is the issue not actually LOX boiloff depleting LOX, but LOX warming and autogenously pressurising the tanks to the point it needs vented, meaning it's now just vented a lot of helium and can't properly maintain pressure as the burn goes on?

Wouldn't LOX boiloff on a coast to GEO be worse than LOX boiloff in LEO?