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

[Pulpstar]

Taken from updates as I wish to discuss the point contained, and my post isn't an update as such !

Here is the raw data sent to me: the ECEF frame is a rotating frame fixed in the Earth.

That C3 looks like an awfully nice round number (considering tracking and likely GNC accuracy) which makes me question the reports that the 2nd stage burned to depletion.

Can we get any clarification on this, was it a targeted delta-V burn or a depletion burn?

If it was a burn to depletion, how does that square with the payload to pluto of 3,500 Kg listed on the website ?

I know there are alot of optimisations (Block 5, more aggressive throttling..) and the 3,500 Kg is probably a fully expendable intentional FH mass throw but 12 -> 200 C3 (The minimum for pluto it seems (I'm assuming no planetary flybys in the number too) seems a stretch to me ^^;

Or am I missing something big ?

[hamerad]

Taken from updates as I wish to discuss the point contained, and my post isn't an update as such !

Here is the raw data sent to me: the ECEF frame is a rotating frame fixed in the Earth.

That C3 looks like an awfully nice round number (considering tracking and likely GNC accuracy) which makes me question the reports that the 2nd stage burned to depletion.

Can we get any clarification on this, was it a targeted delta-V burn or a depletion burn?

If it was a burn to depletion, how does that square with the payload to pluto of 3,500 Kg listed on the website ?

I know there are alot of optimisations (Block 5, more aggressive throttling..) and the 3,500 Kg is probably a fully expendable intentional FH mass throw but 12 -> 200 C3 (The minimum for pluto it seems (I'm assuming no planetary flybys in the number too) seems a stretch to me ^^;

Or am I missing something big ?

The 5-6 hour coast to demonstrate GEO insertion capability wouldn't have helped due to LOX boiloff

[ugordan]

Taken from updates as I wish to discuss the point contained, and my post isn't an update as such !

Here is the raw data sent to me: the ECEF frame is a rotating frame fixed in the Earth.

That C3 looks like an awfully nice round number (considering tracking and likely GNC accuracy) which makes me question the reports that the 2nd stage burned to depletion.

Can we get any clarification on this, was it a targeted delta-V burn or a depletion burn?

If it was a burn to depletion, how does that square with the payload to pluto of 3,500 Kg listed on the website ?

I know there are alot of optimisations (Block 5, more aggressive throttling..) and the 3,500 Kg is probably a fully expendable intentional FH mass throw but 12 -> 200 C3 (The minimum for pluto it seems (I'm assuming no planetary flybys in the number too) seems a stretch to me ^^;

Or am I missing something big ?

I said what I think of that Pluto number almost 2 years ago in this post.

[Johnnyhinbos]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

If the original post wasn't joking, then you just need to look at the video.  The driver side mount is visible in reflection there, as well IIRC as other structural bits on the car's undertray right near the edge of the frame.

edit- 11min into the video referenced here - https://forum.nasaspaceflight.com/index.php?topic=44778.msg1785601#msg1785601
Mods feel free to delete this post if I just missed the sarcasm, or something.

Not joking. Unfortunately the original context was lost because my post was moved from the Update thread. However Steven caught it (maybe his post was in Update as well).

This is the photo I am referring to / and the one Steven enhanced to show where the camera frame was photoshop’d out. Nice work with that BTW!

Again, this image was modified.

[Oersted]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

If the original post wasn't joking, then you just need to look at the video.  The driver side mount is visible in reflection there, as well IIRC as other structural bits on the car's undertray right near the edge of the frame.

edit- 11min into the video referenced here - https://forum.nasaspaceflight.com/index.php?topic=44778.msg1785601#msg1785601
Mods feel free to delete this post if I just missed the sarcasm, or something.

Not joking. Unfortunately the original context was lost because my post was moved from the Update thread. However Steven caught it (maybe his post was in Update as well).

This is the photo I am referring to / and the one Steven enhanced to show where the camera frame was photoshop’d out. Nice work with that BTW!

Again, this image was modified.

Also, SpaceX has updated the launch video with the correct footage from both side boosters.

I've just noticed this video has been removed and the edits folded back into the original stream. That is now at 14 million views and number 1 video on YouTube trending.

It has at least one more change - the flight milestone tracker is now opaque, in the first edit it was semi transparent and you could see the unedited video through it.

SpaceX should REALLY stop fiddling with their images and historical records. Trustworthiness is an essential asset of a company and SpaceX, so far, has lots of it. They shouldn't squander it away foolishly.

[webdan]

My friend received an email with pictures back from the folks we met while waiting watching the launch.

I know they're reduced in size/resolution, but I thought a few were interesting enough to post. Additionally reduced by me.

@Rocket Science: Sorry, no luck finding the ring

PS: Also my card reader has been located. Same place where I let someone borrow a shovel 3 years ago. I'll be getting both back today.

Edit: Wording etc

[JamesH65]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

If the original post wasn't joking, then you just need to look at the video.  The driver side mount is visible in reflection there, as well IIRC as other structural bits on the car's undertray right near the edge of the frame.

edit- 11min into the video referenced here - https://forum.nasaspaceflight.com/index.php?topic=44778.msg1785601#msg1785601
Mods feel free to delete this post if I just missed the sarcasm, or something.

Not joking. Unfortunately the original context was lost because my post was moved from the Update thread. However Steven caught it (maybe his post was in Update as well).

This is the photo I am referring to / and the one Steven enhanced to show where the camera frame was photoshop’d out. Nice work with that BTW!

Again, this image was modified.

Also, SpaceX has updated the launch video with the correct footage from both side boosters.

I've just noticed this video has been removed and the edits folded back into the original stream. That is now at 14 million views and number 1 video on YouTube trending.

It has at least one more change - the flight milestone tracker is now opaque, in the first edit it was semi transparent and you could see the unedited video through it.

SpaceX should REALLY stop fiddling with their images and historical records. Trustworthiness is an essential asset of a company and SpaceX, so far, has lots of it. They shouldn't squander it away foolishly.

Their historical records are presumably intact. The public facing videos are being made more user friendly. They are not changing the historical record, it's all sitting in their office in raw form.

[speedevil]

Their historical records are presumably intact. The public facing videos are being made more user friendly. They are not changing the historical record, it's all sitting in their office in raw form.

Down the stairs, past the sign saying 'beware of the leopard'.

[Apollo-phill]

Nearly 48 hours on from launch  and , from Starman's thoughts ".... here I am sitting in my ' tin can ', far, far away, planet Earth is blue and there is nothing I can do......" 😁

Phill
UK

[.Scott]

I would like to hear other peoples thoughts on what the likely duration of this trip.
A couple of estimates have been "a million year" and "a hundred million years".  But I am not so sure.

The roadster is in an orbit with a period of about 1.6 years.  So every 1.6 years, it will be in the vicinity of Earth's orbit.  Given the relative speed of the Earth and the roadster, it would seem that it has to be within a 12 hour segment of Earth's orbit to be significantly affected.  So, once every 1.6 years it has about a 0.5/365 chance of closing in the right segment of Earth's orbit.  The next factor I will have to guess at.  I would imaging that its orbital plane does not match that of Earths.  So most of the time, it will meet the Earth orbit only in 2 of the 3 dimensions.  So I will guess that the orbital planes are fairly close and it will match well enough in the 3rd dimension about 2% of the time.

So that's one significant interaction every 1.6*365/(0.5*0.02) = about 1 interaction every 60,000 years, about 17 every million years.

That seems to me more like a million year trip than a 100 million year trip.  And if it happens to loose energy relative to the Earth orbit on the first interaction - perhaps a lot less than that.

[LouScheffer]

Taken from updates as I wish to discuss the point contained, and my post isn't an update as such !
[...]

If it was a burn to depletion, how does that square with the payload to pluto of 3,500 Kg listed on the website ?

I know there are alot of optimisations (Block 5, more aggressive throttling..) and the 3,500 Kg is probably a fully expendable intentional FH mass throw but 12 -> 200 C3 (The minimum for pluto it seems (I'm assuming no planetary flybys in the number too) seems a stretch to me ^^;

Or am I missing something big ?

Seemed low to me too, and the total burn time was short.  On SES-16, the previous mission, stage 2 fired for 7:02 (5:54 ascent + 1:08 injection).  On this mission, from the press kit, stage 2 fired for 5:16 ascent + 30 sec (injection), plus a reported 53 second injection, so only 6:39.   Is it possible that a third of the LOX evaporated during the coast?   Seems like a lot.

[speedevil]

Seemed low to me too, and the total burn time was short.  On SES-16, the previous mission, stage 2 fired for 7:02 (5:54 ascent + 1:08 injection).  On this mission, from the press kit, stage 2 fired for 5:16 ascent + 30 sec (injection), plus a reported 53 second injection, so only 6:39.   Is it possible that a third of the LOX evaporated during the coast?   Seems like a lot.

There were a lot of flakes.

First cut.
Assuming average radiative outside temperature of 273K - this is somewhat low for the LEO parts, and high for the parts in darkness at altitude. Assuming barbecue roll means this is reasonable.
The LOX tank is something like 64m^2 in area, and assuming it is at 90K, and neglecting insulation.

Assuming emissivity of '1', we get 20kW in, 230W out, so 20kW goes into boiling the LOX.

The first source I find says 51 calories per gram is needed to boil LOX, which google misinforms me is 200kJ.
(gotta love unit confusion!)
Using 200kJ/kg, as correct, that's a kilo every ten seconds, or over 6 hours, or two tons of LOX.

Warming the LOX up to maybe 108K, with 4 bar in the tanks, does not help appreciably.

So, it's at least of the same order of magnitude as 'a third'.

[IRobot]

I would like to hear other peoples thoughts on what the likely duration of this trip.
A couple of estimates have been "a million year" and "a hundred million years".  But I am not so sure.

The roadster is in an orbit with a period of about 1.6 years.  So every 1.6 years, it will be in the vicinity of Earth's orbit.  Given the relative speed of the Earth and the roadster, it would seem that it has to be within a 12 hour segment of Earth's orbit to be significantly affected.  So, once every 1.6 years it has about a 0.5/365 chance of closing in the right segment of Earth's orbit.  The next factor I will have to guess at.  I would imaging that its orbital plane does not match that of Earths.  So most of the time, it will meet the Earth orbit only in 2 of the 3 dimensions.  So I will guess that the orbital planes are fairly close and it will match well enough in the 3rd dimension about 2% of the time.

So that's one significant interaction every 1.6*365/(0.5*0.02) = about 1 interaction every 60,000 years, about 17 every million years.

That seems to me more like a million year trip than a 100 million year trip.  And if it happens to loose energy relative to the Earth orbit on the first interaction - perhaps a lot less than that.

Depends on orbit inclination. I guess the chance of interaction is much lower than that.
Also Jupiter's disturbance will have an impact, making it less likely to intersect Earth's path.

[Rocket Science]

Anyone catch any comments from the other industry players?

[crandles57]

https://twitter.com/elonmusk/status/961083704230674438



shows Mars on right of track, but is that Mars's current position or position when FH reaches Mars' orbital distance or something else like position at closest approach?

If it is on right of track that would tend to make the orbit more eliptical and be sure of being Earth orbit distance crossing. Seems a bad idea.

If Mars is on left of track when FH reaches Mars's orbital distance, that would tend to alter track to make orbit less eliptical and maybe stop from being Earth crossing orbit?

Does perihelion 0.98 AU refer to current heliocentric orbit excluding any Mars gravity effect or will this be included or is it going to be completely negligible?

Presumably any asteroid belt effect will be negligible?

Perihelion 0.98 AU doesn't seem ideal for stable orbit for hundreds of millions of years or am I missing something?


Edit: looks like it is current planet positions per http://www.theplanetstoday.com/
So how long to mars closest approach?
Is latest still 1.71AU at apohelion and 1.57 year orbital period?
1.71 AU at perihelion is not much more than Mars's 1.66 so nearly half of 1.57 year orbital period? Sounds like Mars will be a long way off by then. Seemed rather different considering Apohelion of 2.61 AU

[LouScheffer]

Seemed low to me too, and the total burn time was short.  On SES-16, the previous mission, stage 2 fired for 7:02 (5:54 ascent + 1:08 injection).  On this mission, from the press kit, stage 2 fired for 5:16 ascent + 30 sec (injection), plus a reported 53 second injection, so only 6:39.   Is it possible that a third of the LOX evaporated during the coast?   Seems like a lot.

First cut.
Assuming average radiative outside temperature of 273K - this is somewhat low for the LEO parts, and high for the parts in darkness at altitude. Assuming barbecue roll means this is reasonable.
The LOX tank is something like 64m^2 in area, and assuming it is at 90K, and neglecting insulation.

Assuming emissivity of '1', we get 20kW in, 230W out, so 20kW goes into boiling the LOX.

The first source I find says 51 calories per gram is needed to boil LOX, which google misinforms me is 200kJ.
(gotta love unit confusion!)
Using 200kJ/kg, as correct, that's a kilo every ten seconds, or over 6 hours, or two tons of LOX.

Warming the LOX up to maybe 108K, with 4 bar in the tanks, does not help appreciably.

So, it's at least of the same order of magnitude as 'a third'.

On the other hand, it looks like it was spinning end-over-end.  I think this makes sense, as it scrunches the LOX down to one end of the tank, much better than spreading it over the surface in a spit-roll.  Also, this will keep the LOX and kerosene apart, so the kerosene does not freeze.   Furthermore, the booster is painted white, and most of the sun's energy is in the visible.

Also, Apollo did not seem to have a huge amount of boiloff during coast, and I think the LOX tank was also just painted aluminum.  From Apollo lunar landing launch window: The controlling factors and constraints:

The parking orbit duration was defined by space vehicle system considerations. The minimum was set at 1.4 hours with a maximum duration is 4.5 hours from earth orbit insertion to the beginning of the trans lunar injection (TLI) and was limited by the launch vehicle capability to provide attitude control and by the launch vehicles battery lifetime (approximately 13 hours).

It goes on to list propellant boiloff as only a minor consideration.

So overall, a third lost to boiloff seems like a lot.

[meekGee]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

If the original post wasn't joking, then you just need to look at the video.  The driver side mount is visible in reflection there, as well IIRC as other structural bits on the car's undertray right near the edge of the frame.

edit- 11min into the video referenced here - https://forum.nasaspaceflight.com/index.php?topic=44778.msg1785601#msg1785601
Mods feel free to delete this post if I just missed the sarcasm, or something.

Not joking. Unfortunately the original context was lost because my post was moved from the Update thread. However Steven caught it (maybe his post was in Update as well).

This is the photo I am referring to / and the one Steven enhanced to show where the camera frame was photoshop’d out. Nice work with that BTW!

Again, this image was modified.

Here's a screen grab from the four-hour "starman views" youTube.

The side camera mount continuously appears and disappears as the lighting changes.

No photoshop necessary.

(And same goes to the people who claimed that the wheels in the pre-launch Roadster pictures were "clearly photoshopped in")

[Mongo62]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

If the original post wasn't joking, then you just need to look at the video.  The driver side mount is visible in reflection there, as well IIRC as other structural bits on the car's undertray right near the edge of the frame.

edit- 11min into the video referenced here - https://forum.nasaspaceflight.com/index.php?topic=44778.msg1785601#msg1785601
Mods feel free to delete this post if I just missed the sarcasm, or something.

Not joking. Unfortunately the original context was lost because my post was moved from the Update thread. However Steven caught it (maybe his post was in Update as well).

This is the photo I am referring to / and the one Steven enhanced to show where the camera frame was photoshop’d out. Nice work with that BTW!

Again, this image was modified.

Here's a screen grab from the four-hour "starman views" youTube.

The side camera mount continuously appears and disappears as the lighting changes.

No photoshop necessary.

Thank you. I was not comfortable with the accusations being leveled at SpaceX that they deliberately Photoshopped the image. It seems clear that at the correct sun angle, the camera mount would be in shadow and hence invisible.

[Kansan52]

Yep. Similar to "Why no stars showing". The camera's iris adjusts to the brightest source. A bright source means the iris closes and very little light comes in or the bright source will damage the pick-up (usually a CCD device these days).

If memory serves, Apollo lost one of the video cameras on the moon because accidentally pointing it at the Sun destroyed the Vidicon.

[Johnnyhinbos]

And photoshop’d. In the very least the driver side camera bracket was airbrushed out. Wished they just left it real. Now I look at it and wonder just how touched up it is...

Here's an enhanced image. There is a lighter area to the right (R,G,B) = (2,2,4) and (2,1,6). Looks like the right camera has been rubbed out. They should have used the same dark pixels as in deep space of (2,0,3). You can also see where the shadow of the car crosses diagonally at the bottom of the lighter area. Also see some darker (2,0,1) imaging artefacts possibly from an imperfect CCD chip. Maybe its a secret message! :-)

See Steven’s post quoted, along with his enhanced image. It’s not an accusation, rather an observation. To me it’s not a desecration of a historical image, rather there’s artistic license taken to enhance the visual. As has been mentioned, original exists somewhere - and yes, it’s possible that the camera frame is there but in shadows, though I doubt it.