Spacex Dec 23 twilight launch, "looked horizontal"

Leifer

Senior Member.
The Spacex Falcon launch on Dec 23rd, 2017 was spectacular, mainly because it happened soon after twilight. The sky was dark, but the rocket's plume was lit by sunlight, high above.

But several NASA skeptics are claiming "It didn't go very high" and "It was flying horizontally not upward" (paraphrased)

The rocket flew North-to-South over the Pacific ocean, and the spent first-stage booster was deployed and ditched off the coast of Baja, Mexico.
Here is the general NOTAM, NOTMAR map area for the booster ocean ditch.... (M1340 Iridium-4 water landing).
https://www.google.com/maps/d/viewe...&ll=31.06553227915776,-119.73669807854498&z=6
M1304_iridium_spacex.jpg
Although I understand it (visually in my head), trying to explain "why" the launch seemed to be going "horizontal" is difficult because.... trying to explain overhead perspective on a sphere is complicated in words.

Can someone find a Google Earth trajectory image (track) of the rocket path ?
 
I did try to explain that, because it was over the Pacific, and people in Arizona were able to see it, it must have been very high.
 
https://en.m.wikipedia.org/wiki/Gravity_turn

Most of the delta-V for an orbital launch is horizontal, not vertical. Shortly after launch a short pitch over maneuver is performed, after which gravity slowly makes it rotate towards horizontal.

In some cases this goes all the way to orbit, with the burn ending completely horizontal to circularize the orbit. In others this will stop when the desired apogee is achieved, and followed by a horizontal circularization burn to establish orbit.
 
Launches don't go straight up though do they? After the initial ascent they pitch over into a more horizontal flight
Excatly. To enter low-earth orbit they need to be travelling at a horizontal speed of about 17,500mph. You don't get that by launching vertically!
 
Yes, the most efficient way to enter an orbit is to leave gravity and head towards an orbit, at the same time. (in an arc) Speed (semi-hoizontally) is needed to reach/gain orbital velocity.

The people who don't understand this are not stupid, they just haven't thought about it very much.
 
Yes, the most efficient way to enter an orbit is to leave gravity and head towards an orbit, at the same time. (in an arc)

The people who don't understand this are not stupid, they just haven't thought about it very much.

I think it's the idea that outer space is a long way away and you have to travel straight up for ages to get there. In fact, "outer space" starts at 100km (a little over 60 miles) above the Earth. As Fred Hoyle said, you could drive there in less than an hour, if your car went straight up.

LEO is a little higher than that: typically about 500-1,000 miles up, but with a rocket it really doesn't take that long to reach that height - and you don't want to go any higher than that, so of course you angle over towards the horizontal pretty quickly.
 

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I tried to explain it to some NASA antagonists... this very thing.
But most people don't quite understand perspective, and when they see the rocket going almost horizontal, they don't understand the perspective part of it.
If the rocket was really going horizontal (and not very high), it would quickly dip over the horizon because of perspective.. just like a long contrail dips toward the ocean, even though it's at level flight.

But people in Arizona saw it too, which means it was indeed very high.
 
Thanks Mick.
I searched online for a trajectory of the recent launch, but could not find anything (yet).
But records of other launches would work or help.
Even the Apollo missions needed to orbit the earth first, before a slingshot to the moon.
(it gets difficult to use the Apollo missions as an example online, because of so much suspicion)
 
I tried to explain it to some NASA antagonists... this very thing.
But most people don't quite understand perspective, and when they see the rocket going almost horizontal, they don't understand the perspective part of it.
If the rocket was really going horizontal (and not very high), it would quickly dip over the horizon because of perspective.. just like a long contrail dips toward the ocean, even though it's at level flight.

But people in Arizona saw it too, which means it was indeed very high.

The thing is, even though it is really high, it is still roughly horizontal (by the time it reaches that height) and therefore does dip over the horizon. It's a nice illustration of the Earth's curvature, and yet Flat Earthers claim it shows the rockets ditching in the sea, using memes like this!



But I digress...
 
It's a nice illustration of the Earth's curvature

And it's a good illustration of the curvature of the earth, .... that anything circling the globe will eventually dip toward (over) the horizon.
But FE belief in "no satellites possible" corners them into saying "it just crashed into the ocean".
 
Disclosure... I have been working in Elon Musk's principle home as a "decorative painter" and artist for months now, and I have yet to find his "secret underground tunnel" per online rumors.
I met him once, but have not sat down with him to discuss these things. ;)
Evidently he is aware of online conspiracy game-playing, as he mockingly tweeted about the launch, "Nuclear alien UFO from North Korea" as well as commenting with other CT jests over the years.
.
 
Yes, the most efficient way to enter an orbit is to leave gravity and head towards an orbit, at the same time. (in an arc) Speed (semi-hoizontally) is needed to reach/gain orbital velocity.

The people who don't understand this are not stupid, they just haven't thought about it very much.
Come on, its not exactly rocket science....

...err hold on, it IS rocket science ;)
 
Here's a reasonable description of the launch, of what people saw.....


Edit by the video maker,...
"Apologies: I made a huge Mistake - The gap in the trail is the staging event."
 
Here's SpaceFlightInsider's recollection, for reference....


http://www.spaceflightinsider.com/o...sky-iridium-launch-closes-banner-year-spacex/

The countdown proceeded smoothly. A few seconds before the planned liftoff, the nine first stage Merlin 1D engines ignited and powered up to full power. Once the onboard computer confirmed all of the engines were healthy, the launch latches were commanded to be released, letting loose the full might of the Falcon 9.

Together, the first stage produces some 1.7 million pounds-force (7,600 kilonewtons) of sea-level thrust at liftoff. In just five seconds, the rocket cleared the transporter erector before beginning its pitch-over south toward its designated orbit.

About 1 minute, 14 seconds into the flight, the vehicle reached maximum dynamic pressure (max Q), which is the point where the stresses on the vehicle are at its maximum.

Two minutes, 33 seconds after liftoff, the first stage consumed its liquid oxygen and rocket-grade kerosene fuel and separated from the second stage, as planned.

Falcon 9’s second stage is powered by a lone Merlin 1D Vacuum engine. It produces about 210,000 pounds-force (934 kilonewtons) of thrust and burns for an additional six minutes before cutting off at about 9 minutes after leaving California.

During the second stage’s flight uphill, the payload fairing was jettisoned. It was protecting the 10 Iridium NEXT satellites from the friction of the atmosphere in the early part of the flight, but after about 3 minutes, 11 seconds, it was no longer required.

After a 43-minute coast phase, the Falcon 9 second stage engine ignited for a second time – this time for a brief 11 seconds – to circularize its polar orbit.

Less than an hour after leaving the launch pad (57 minutes and five seconds), the 10 Iridium NEXT satellites began deploying. Each deployment consisted of pairs of satellites being released. The final set was deployed at mission elapsed time of 1 hour, 12 minutes.
Content from External Source
I believe the "fairings" could be seen after shedding - as tiny white-ish dots, in higher res videos or better cameras.

Here is an official Spacex launch video, for reference also. (it's long, but here it starts at launch...)


@ 24:32 there is a trajectory Earth map shown. This may be a simulation, I think so.
You can scroll forward to view progress and snapshots of the circular navigation over the South Pole..
 
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Yes, the most efficient way to enter an orbit is to leave gravity and head towards an orbit, at the same time. (in an arc) Speed (semi-hoizontally) is needed to reach/gain orbital velocity.

The people who don't understand this are not stupid, they just haven't thought about it very much.

So you can agree with them then. It looks horizontal because it is. It has to be to achieve orbit. Maybe with a simple diagram
 
What the
So you can agree with them then. It looks horizontal because it is. It has to be to achieve orbit. Maybe with a simple diagram

James Oberg covered exactly this issue in an article about the Sputnik I launch, apparently many people on the ground thought the rocket was going to crash back to Earth when it changed trajectory to allow it to enter orbit, the key point being that at the time, they were more used to missile tests which used a different trajectory.

The first Sputnik presented an entirely different visual apparition to those who witnessed it actually taking off. Workers at the launch site near the Aral Sea in central Asia watched it soar into space during its near-midnight launch. For orbital mechanical reasons that only later became “obvious,” what these observers saw convinced them for several desperate minutes that the launch was failing.

During the previous months’ test flights of the R-7 (“Semyorka”) intercontinental ballistic missile, ground observers had seen the multi-flamed rocket soar high into the sky, then arc to the northeast as it continued to climb. The trajectory was “lofted,” thrown at a high angle to peak about 1,000 kilometers high, halfway to its impact point.

On later flights, which worked, the engines faded with growing distance while still high in the sky, probably halfway to the zenith. But for earlier flights, seared into the fresh memories of the witnesses, the light in the sky flared and then fell back toward the horizon as the engines exploded and burned. Just as with shot-down warplanes of the still-recent “Great Patriotic War” (aka World War 2), of which most space workers were veterans, a flame falling toward the horizon was a doomed craft.
Content from External Source
http://www.thespacereview.com/article/971/1
 
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