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SpaceX Launch Last Year Punched Huge, Temporary Hole In the Ionosphere (arstechnica.com)
The Falcon 9 rocket that launched last August reportedly ripped a temporary hole in the ionosphere due to its vertical launch, which Ars Technica notes as being rather unusual: Contrary to popular belief, most of the time when a rocket launches, it does not go straight up into outer space. Rather, shortly after launch, most rockets will begin to pitch over into the downrange direction, limiting gravity drag and stress on the vehicle. Often, by 80 or 100km, a rocket is traveling nearly parallel to the Earth's surface before releasing its payload into orbit. However, in August of last year, a SpaceX Falcon 9 rocket launch from California did not make such a pitch over maneuver. Rather, the Formosat-5 mission launched vertically and stayed that way for most of its ascent into space. The rocket could do this because the Taiwanese payload was light for the Falcon 9 rocket, weighing only 475kg and bound for an orbit 720km above the Earth's surface. As a result of this launch profile, the rocket maintained a nearly vertical trajectory all the way through much of the Earth's ionosphere, which ranges from about 60km above the planet to 1,000km up. In doing so, the Falcon 9 booster and its second stage created unique, circular shockwaves. The rocket launch also punched a temporary, 900-km-wide hole into the plasma of the ionosphere.
Why does a perpendicular penetration create a bigger hole than a (much longer) almost parallel traversal?
It does not matter whether it is perpendicular or parallel, the matter is Taiwan
The Ionosphere is allergic to everything that has any relationship with Taiwan, including that Taiwanese payload on Falcon 9 rocket
Huh!!??
... still they are damaging to our eco system. Time for the space elevator inventions? Back in the '60 they were already being a vision of modern surface to space freighters.
Bach says it all.
First we were destroying the ozone layer with aerosol, and now we're destroying the Ionosphere with rockets. And next we'll be destroying another layer with something else.
The 20th and 21st centuries have been best described by: let's innovate without worrying about the consequences; let's claim to be supporters of science, without applying its principles.
An application of modern philosophy that destroys our world. And a rejection of classical/medieval philosophy, which is the underpinning of true science.
Keep doing it and you will soon see a nice spike in skin cancers caused by extreme ultraviolet light getting through to the surface.
If you are testing a new rocket platform you want to expose the rocket to as much stress as possible! If you want to see how much stress your vehicle can take you push the envelope. Falcon 9 did just that, and it did it well.
When I test my 3d printed r/c aircrafts.. I push them to the limit. I want to see if the adhesive holds well. I want to see if my thin wall printing hold up. I also want to see if my landing gear is strong enough. I take my aircraft up to the r/c flight ceiling, power dive and pull back at 100% full throttle when I'm close 50ft elevation.
This is what you do to prove out a design. When you want to expose a rocket platform to stress you fly straight up into space.
The Falcon 9 Booster and Secondary stage is designed for this.
The light payload and vertical launch tell me that SpaceX was more interested in having a successful soft landing than anything else. That's one of the major trade-offs in the reusable rocket approach, you need to compromise what you can launch in order to have enough fuel to recover the rocket.
Contrary to popular belief, most of the time when a rocket launches, it does not go straight up into outer space.
I've never known anyone who thought that satellite launches went straight up. Did any Slashdot readers have that belief before reading this article, or know people who think that?
shortly after launch, most rockets will begin to pitch over into the downrange direction
It's called a gravity turn, and it starts just about the point where you hear "... has cleared the tower".
limiting gravity drag and stress on the vehicle
That's not why it's done. Going straight up would get you through the dense part of the atmosphere quicker and the gravity would balance out, both of which should reduce stress on the vehicle.
The gravity turn is done because the height (200+ km) is a tiny part of a rocket launch. You could go that distance in a couple of days on a bicycle (though not upwards of course). The important thing is the horizontal speed, around 8 km (5 miles) per SECOND. You could go straight up for 200 km, then do a 90 degree turn, and do another burn for the speed, but that uses a lot more fuel than a nice curve gaining speed and height at the same time.
"Derp dis why your not lowed have nice thing m'kay. You can do something we just made up m'kay"
Surely a straight launch puts much less stress on a vehicle, since it spends less time/distance in the atmosphere. Also, the Falcon 9 is far from a new rocket.
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This has happened before. If you google 'skylab ionosphere' you'll find that a large hole was made in the ionosphere during the launch of the Skylab space habitat. After a bit if study it was decided that this was due to the injection of water and other materials into the ionosphere which caused the sudden large decrease in ionization. Basically, this injection changed the electron loss rate in the area to the point where it was much greater than the solar EUV-driven electron production rate. The shock wave can create the ripples, but not the large hole. This will happen any time the main boosters are running when the rocket passes through the main part of the ionosphere (roughly 300-400 km up).
There are so many physics problems with this story I don't even now how it got published.
most rockets will begin to pitch over into the downrange direction, limiting gravity drag and stress on the vehicle
Gravity drag??? No stress on the vehicle is caused by friction with the air in the atmosphere. The sooner you can get out of the atmosphere (roughly 100km altitude), the sooner you can limit that drag get the vehicle to final orbital speed. Rockets pitch over because the whole point is to get to 'orbital speed' which is the velocity 'parallel' to the earth's surface, not perpendicular to it. A rocket can't fly straight up and make a 180 turn any more than you can drive your car around a hairpin turn at 200 km/h. Rockets launch in a gentle arc from vertical to parallel. They would skip the initial vertical portion if they could. The most efficient launch would be horizontal in a perfect atmosphere free world. Lunar satellites launched from the moon (if we ever get there) will not launch vertically. But atmospheric drag is huge and has to be limited at all costs.
the rocket maintained a nearly vertical trajectory all the way through much of the Earth's ionosphere, which ranges from about 60km above the planet to 1,000km up
No, it surely did not. The final orbit of the satellite is 720Km. The orbital velocity for an object at an altitude of 720K is 7,496m/s (http://www.softschools.com/formulas/physics/orbital_velocity_formula/76/). That's 26,988 km/h. Think about that speed for a moment. 27 'thousand' km/h. That's how fast the satellite has to be going 'around' the earth, not vertically up but around, to maintain an orbit at 720km. At about 100KM altitude into this launch, the first stage quits and the rocket has already achieved a velocity of 6,500km/h. It's still short of orbital velocity by more than 20,000km/h. With only 520 km of altitude to go. It's not travelling anywhere near 'vertical' any more. The next phase of the launch is all about gaining orbital speed. And it's less than a 10th of the way into the ionosphere.
I have no doubt that every rocket launch has some effect on the ionosphere. But this launch was no different than any other launch, which makes me wonder why it was even targeted for a news story. But there it is in TFA
When it comes to self-driving systems, in which GPS navigation results are integrated into the system, the impacts of these errors can become much more important, Lin said
So there you go. Rocket launches 'can' affect GPS accuracy, which in turn 'can' affect self driving systems, which well, 'can result in a top news story', because - self driving car accident.
The last safe haven of pure science, rocket science, dragged into the muck of media hyperbole. Just shoot me now.
Correct. That said, SpaceX still does (on other launches) the sort of stress testing that the previous AC was describing; they've increasingly pushed returning stages through more and more aggressive entry profiles. Obviously they haven't been as aggressive on ascent since you have a customer's payload then, but...
Is your job to sit under bridges and jump out at unsuspecting travellers?
Yeah! Stoopid F$%^!
Why doesn't he build an electric Rocket?
I thought raw altitude got it there, but 'rotational velocity' kept it there.. why doesn't it fall out of the sky?
But it's fighting gravity more intensely - when it leans over it starts getting some aerodynamic lift as well.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Here's the link to the actual paper:
https://agupubs.onlinelibrary....