Author Topic: Could we visualize the Blue Origin and SpaceX payload trajectories TO SCALE?  (Read 38476 times)

Offline Oersted

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It annoys me slightly to hear Jeff Bezos compare the recent Blue Origin test flight 2 with the SpaceX Orbcomm-2 mission. I wonder if somebody could use their Photoshop-fu to make a visualization of the trajectory of the BO capsule to scale with those of the Orbcomm satellites. The challenge of course is that the trajectories don't really compare, but that's also exactly why it would be very telling  to see them together.

Offline Nilof

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Here's one from another thread:
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline NovaSilisko

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I don't know how accurate that one is. It looks very disproportionate, and the boostback burn seems to start *very* late. Plus it says the second stage trajectory isn't to scale, but what does that even mean?
« Last Edit: 12/23/2015 08:46 pm by NovaSilisko »

Offline oiorionsbelt

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They have corrected that graphic with this one.

Offline Oersted

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Ah, the corrected graphic is nice, thanks for posting it.

That one is a graphic of the booster trajectories, though. What I'm looking for is a visualization of the payload trajectories. The boosters are just the means, the payloads are the purpose. Looking at booster trajectories we don't really get an idea of the huge difference between the two launch systems. Comparing the tiny pop above 100km. of BO test flight 2 with the orbital trajectories of the Orbcomm satellites would really drive the message home.

Offline savuporo

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The graphic would get even better with a visual cue of speed on the trajectory. Color coded mach number gradient or such

Also making this into an animation with proportionally reduced timescales wouldn't be too difficult
« Last Edit: 12/23/2015 09:12 pm by savuporo »
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Offline Oersted

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Good ideas. Going totally ambitious it would of course also be great to see all eleven Orbcomm trajectories weaving a web around the Earth, just to  underline the difficulty of actually placing all those satellites in their correct orbit. Maybe simpler is better, though....
« Last Edit: 12/23/2015 09:28 pm by Oersted »

Offline whitelancer64

The comparative graphic should portray the trajectories more like thus:

No, that's wrong. Even to an observer at the launch site, the Falcon 9 still goes higher than the New Shepard. The difference in the upward distance the Falcon 9 travels is greater than the curvature of the Earth at ~95 km downrange.
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Offline Robotbeat

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The comparative graphic should portray the trajectories more like thus:

No, that's wrong. Even to an observer at the launch site, the Falcon 9 still goes higher than the New Shepard. The difference in the upward distance the Falcon 9 travels is greater than the curvature of the Earth at ~95 km downrange.
That is just your opinion.
No, it's not.
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Offline llanitedave

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The resistance to humor is strong in this one.
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Offline meekGee

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New Shepard reached 100+ km (same as Space Ship One) and fell right back down.  Same as what SS1 did over 10 years ago.

SpaceX's F9 crossed that altitude doing almost 6000 km/h, and carrying a second stage that weighs more than the entire New Shepard...

It then released that second stage which rocketed on to orbit, continued on inertia to 200 km while also using its engines to reverse the horizontal velocity and aim for the landing site.

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Offline strangequark

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The resistance to humor is strong in this one.

The amazing peoplem in this thread is strong.
Can we stop with the "rocket" measuring contest already? Each team is to be congratulated for accomplishing an amazing feat, but Blue takes the ring for first vertical, powered landing from space. The rest is just juvenile nitpicking, and until someone recovers a second stage, that part is totally irrelevant.

Offline QuantumG

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until someone recovers a second stage, that part is totally irrelevant.

I was going to say, until someone actually lowers the cost of launch by reuse it's all irrelevant.. but it's actually more than that. Recovering the booster actually tells you things that you can use to make your engines and structures more reliable, even if you never refly it.
Human spaceflight is basically just LARPing now.

Offline meekGee

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The resistance to humor is strong in this one.

The amazing peoplem in this thread is strong.
Can we stop with the "rocket" measuring contest already? Each team is to be congratulated for accomplishing an amazing feat, but Blue takes the ring for first vertical, powered landing from space. The rest is just juvenile nitpicking, and until someone recovers a second stage, that part is totally irrelevant.

You had it there right up till the ring part...

The "Karman line" is an arbitrary line that was pulled from obscurity and pushed into our collective consciousness by the good people of the marketing department of Virgin Galactic...   Orbital people are really embarrassed to even bring up the Karman line in conversation relating to space...  If you're going to give rings for arbitrary goals, you'll need a lot of them... 

The X-15 was the first to cross the 50 mile line with a reusable rocket (which re-flew)
VG was the first private company to cross the 100 km line with a reusable rocket (which re-flew)
SpaceX was the first private company to cross the 100 km line with a reusably-planned vertical rocket and slow down to below 100 km/h
BO was the first private company to cross the 100 km line with a reusably-planned vertical rocket and soft land
Nobody yet crossed the 100 km line with a reusable vertical rocket that actually got reused.
EDIT: I forgot: SpaceX was the first private company to cross the 200 km line with a reusably-planned vertical rocket and soft land...


In short - everyone gets rings.  And when everyone's special - nobody's special.

Only one company is doing its stuff though with real, commercial, revenue generating orbital vehicles - and so while you're handing out the rings, us amazing people will continue to feel that the BO and SpaceX achievements are not even on the same scale...

Peace!
« Last Edit: 12/24/2015 02:53 am by meekGee »
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Offline savuporo

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The comparative graphic should portray the trajectories more like thus:
You misspelled 'egocentric'
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Offline CuddlyRocket

The "Karman line" is an arbitrary line that was pulled from obscurity and pushed into our collective consciousness by the good people of the marketing department of Virgin Galactic...

The Karman line is not arbitrary; it is based on physical principles. Nor is it obscure; it's used by the Fédération Aéronautique Internationale to define the boundary between aeronautics and astronautics for record setting purposes. Also by NASA for the purpose of giving out civilian astronaut wings. And SpaceShipOne won (in 2004) the Ansari X-Prize (established in 1996), which used the Karman line as its criteria; it wasn't dreamed up by Virgin's marketing department!

Quote
Orbital people are really embarrassed to even bring up the Karman line in conversation relating to space...

Weird thing to be embarrassed about! Sounds more like oneupmanship to me; reminds me of those yachtsmen who say you haven't really been out on the ocean on a yacht if you're still over the continental shelf!

Quote
If you're going to give rings for arbitrary goals, you'll need a lot of them... 

The X-15 was the first to cross the 50 mile line with a reusable rocket (which re-flew)
VG was the first private company to cross the 100 km line with a reusable rocket (which re-flew)
SpaceX was the first private company to cross the 100 km line with a reusably-planned vertical rocket and slow down to below 100 km/h
BO was the first private company to cross the 100 km line with a reusably-planned vertical rocket and soft land
Nobody yet crossed the 100 km line with a reusable vertical rocket that actually got reused.
EDIT: I forgot: SpaceX was the first private company to cross the 200 km line with a reusably-planned vertical rocket and soft land...

The X-15 reached 100 km. But you forgot the Space Shuttle, which was a vertically launched rocket that reached and returned from orbit and soft-landed - and then did it again! I suppose the operative distinction here is 'under its own power'?

The F9 1st stage is a greater engineering achievement than the Blue Origin booster; but the fact remains that the latter was the first to launch under its own power, get to space and return to a soft-landing. Though the F9 1st stage could certainly claim the altitude record for such a rocket!

Quote
Only one company is doing its stuff though with real, commercial, revenue generating orbital vehicles - and so while you're handing out the rings, us amazing people will continue to feel that the BO and SpaceX achievements are not even on the same scale...

That's undoubtedly true. But in 'firsts' and other records, scale is not a relevant criteria. No-one says the Wright brothers weren't the first to achieve powered flight because it wasn't a commercial, revenue generating flight and it only carried one man for 120 ft.

Elon would have been well advised to just congratulate Blue Origin; chuckle in chagrin at being technically pipped at the post for this particular milestone, and let the differences in scale and significance etc speak for themselves. Same goes for us SpaceX amazing people! :)

Offline meekGee

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It would be a lot more convincing if it were, for example, 112.4, or 96.5 km.
Further, the Navy, which worked in miles, happened to use 50.  Not 53.2, or 48.2 or even 62.1371 (which is 100 km in miles...) 

You see what I'm saying, right? 

The fact that it is used by people doesn't argue that it has any physical significance.  Somewhere, someone, had to draw a line.  Karman stepped up.

It's like the line between, oh, childhood and adulthood. Lots of people use 18, some use 21.  But nothing of note happens on that day other than a change in legal status.

--

In the "race to space", hitting 100 km altitude at 0 velocity is meaningless.  It is not an achievement of note.  For Virgin Galactic and other companies selling suborbital rides, it's a marketing feature.  Otherwise, what would they sell?   

What if BO's rocket had gone up to 98 km and soft landed.  Would it have been a fundamentally different achievement?


The "Karman line" is an arbitrary line that was pulled from obscurity and pushed into our collective consciousness by the good people of the marketing department of Virgin Galactic...

The Karman line is not arbitrary; it is based on physical principles. Nor is it obscure; it's used by the Fédération Aéronautique Internationale to define the boundary between aeronautics and astronautics for record setting purposes. Also by NASA for the purpose of giving out civilian astronaut wings. And SpaceShipOne won (in 2004) the Ansari X-Prize (established in 1996), which used the Karman line as its criteria; it wasn't dreamed up by Virgin's marketing department!

Quote
Orbital people are really embarrassed to even bring up the Karman line in conversation relating to space...

Weird thing to be embarrassed about! Sounds more like oneupmanship to me; reminds me of those yachtsmen who say you haven't really been out on the ocean on a yacht if you're still over the continental shelf!

Quote
If you're going to give rings for arbitrary goals, you'll need a lot of them... 

The X-15 was the first to cross the 50 mile line with a reusable rocket (which re-flew)
VG was the first private company to cross the 100 km line with a reusable rocket (which re-flew)
SpaceX was the first private company to cross the 100 km line with a reusably-planned vertical rocket and slow down to below 100 km/h
BO was the first private company to cross the 100 km line with a reusably-planned vertical rocket and soft land
Nobody yet crossed the 100 km line with a reusable vertical rocket that actually got reused.
EDIT: I forgot: SpaceX was the first private company to cross the 200 km line with a reusably-planned vertical rocket and soft land...

The X-15 reached 100 km. But you forgot the Space Shuttle, which was a vertically launched rocket that reached and returned from orbit and soft-landed - and then did it again! I suppose the operative distinction here is 'under its own power'?

The F9 1st stage is a greater engineering achievement than the Blue Origin booster; but the fact remains that the latter was the first to launch under its own power, get to space and return to a soft-landing. Though the F9 1st stage could certainly claim the altitude record for such a rocket!

Quote
Only one company is doing its stuff though with real, commercial, revenue generating orbital vehicles - and so while you're handing out the rings, us amazing people will continue to feel that the BO and SpaceX achievements are not even on the same scale...

That's undoubtedly true. But in 'firsts' and other records, scale is not a relevant criteria. No-one says the Wright brothers weren't the first to achieve powered flight because it wasn't a commercial, revenue generating flight and it only carried one man for 120 ft.

Elon would have been well advised to just congratulate Blue Origin; chuckle in chagrin at being technically pipped at the post for this particular milestone, and let the differences in scale and significance etc speak for themselves. Same goes for us SpaceX amazing people! :)
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Offline sdsds

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It would be a lot more convincing if it were, for example, 112.4, or 96.5 km.

Theodore von Kármán was like a god. Are you dissing my religion? ;-)

Seriously, though: the STS entry interface was defined as 400,000 feet (121.92 kilometers) for essentially the same reason von Kármán chose 100 km. They're both nice round numbers near the value important for flight control. EI is higher because the Shuttle was coming down and they wanted to err on the safe side. Von Kármán was thinking about ascent, so the safe side to err on was in the other direction....
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Offline obi-wan

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It would be a lot more convincing if it were, for example, 112.4, or 96.5 km.

Theodore von Kármán was like a god. Are you dissing my religion? ;-)

Seriously, though: the STS entry interface was defined as 400,000 feet (121.92 kilometers) for essentially the same reason von Kármán chose 100 km. They're both nice round numbers near the value important for flight control. EI is higher because the Shuttle was coming down and they wanted to err on the safe side. Von Kármán was thinking about ascent, so the safe side to err on was in the other direction....

While 400,000 feet is a nice round number, "entry interface" has a specific definition of the altitude at which aerodynamic forces become discernable in an orbital entry - where the "0.05 g" indicator on the panel lights up. 400Kft is appropriate for most orbital spacecraft with typical ballistic coefficients. A truly equivalent value for launch would be where the aerodynamic forces become insignificant - in practical terms, at fairing jettison, which is really a function of dynamic pressure more than just altitude. 100 km was set by the FAI to define "space" (as opposed to "aviation") records.

Offline meekGee

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:)

Exactly - 400,000' is equally valid.   And also depends on the vehicle.   And reaching it a 0 m/s make it not very "EIy"...

But we're digressing - we can take that to the BO or VG threads. 

I'm off, about 3 posts too late...   :)

I'll go read about Theodore von Kármán now.


It would be a lot more convincing if it were, for example, 112.4, or 96.5 km.

Theodore von Kármán was like a god. Are you dissing my religion? ;-)

Seriously, though: the STS entry interface was defined as 400,000 feet (121.92 kilometers) for essentially the same reason von Kármán chose 100 km. They're both nice round numbers near the value important for flight control. EI is higher because the Shuttle was coming down and they wanted to err on the safe side. Von Kármán was thinking about ascent, so the safe side to err on was in the other direction....
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