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What are the two bright objects separating from the Falcon 9?
On the recent Iridium 1 launch the separation of the first and second stages can be seen at T+3:50. In the following screenshot we see the second stage burning at the lower left of the frame and the first stage dropping away at the upper right.
What…
Happy Phantom
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Is atmospheric skimming for propellant feasible?
A recent comment in a discussion of satellite refueling mentioned the
possiblity of a spacecraft dipping into the atmosphere from LEO to
obtain oxygen. Similarly, the science fiction RPG Traveller proposes
scooping hydrogen from gas giant…
Russell Borogove
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How much of a problem is space junk, and how can we clean it up?
A lot is heard about space junk these days, but how much of a problem is it really to orbiting satellites? Are there many cases of spacecraft being damaged by it, or is it a bit overhyped?
Following on from that, if it is an issue then what measures…
berry120
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Why does the video feed always fail during Falcon 9 landings?
I'm in love with SpaceX and Falcon 9, I watch every live stream and the most special, most amazing, most thrilling part of each launch is the 1st stage landing. Seeing the smoke (or vapor) clear and seeing that 33m tall rocket landed safely within 2…
Coomie
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What defines the radius of a ball of gas like Jupiter?
I've seen statements to the effect of: "the gravity on the surface of Jupiter is about 2.5 times that of Earth". The problem with such a statement is that as essentially a ball of gas, Jupiter is not believed to have a solid surface. Behind the…
Anthony X
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How long does it take for a signal to travel between Earth, and Juno at Jupiter?
How long would it take for Juno's communication to reach the Earth? In other words: what is the time delay between perception by Juno and perception by NASA researchers?
Andras Hirschler
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Is the ideal transfer between two arbitrary planar orbits always a bi-tangential ellipse?
I was reading Hollister David's short paper on bi-tangential transfers. The example he uses is a transfer between a planar circular and an elliptical orbit. I am wondering: Is an ideal, that is, the lowest $\Delta v$ cost, transfer between two…
SE - stop firing the good guys
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Why does the Soyuz parachute pulsate?
During the recent return of Expedition 47 from the ISS, I noticed the main parachute of their Soyuz capsule pulsating. You can see it in this video:
"Flat":
"Domed":
My wife noted that it looks a little like a jellyfish, moments later I saw this…
James Thorpe
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What are the end-of-life options for large classified satellites?
The Delta IV Heavy recently launched NORL-65 to a low Earth orbit. Some of these missions will be in the range of 390 km altitude with circular orbits. Plus, the Delta IV Heavy is a big rocket, with a LEO payload of 22 tons.
Considering that it's…
AlanSE
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Why was Titan the first celestial body beyond Mars to be landed on?
If my memories are accurate, then there's only one celestial body beyond Mars, on which any man-made device was landed. Pictures made there are, in fact, quite popular among space fans.
But why Titan?
One would assume Europa is much more of an…
Zoltán Schmidt
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How does a single rocket place multiple satellites into orbit?
Nowadays, many rockets transport more than one satellite in orbit. But how does a single rocket place multiple satellites into their orbits?
Do all rockets which place multiple satellites into orbit follow the same mechanism? What is the mechanism…
Hash
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Why is TEA-TEB chemical ignition used instead of spark ignition?
Both the Saturn V and the Falcon 9 use TEA-TEB to ignite their kerosene-fueled engines. TEA-TEB is pyrophoric, igniting spontaneously on contact with air. This poses handling issues; it must be stored in nitrogen.
It's also an expendable resource…
Russell Borogove
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Would the blast clearing technique used in snorkeling work in an EVA situation?
Luca Parmitano wrote about his experience with water filling his helmet during EVA on the International Space Station. It's a harrowing account and he explains part of his thought process:
I force myself to stay calm and, patiently locating the…
Jon Ericson
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Can spacecraft be made invisible to stations on Earth?
Can spacecraft be made invisible to ground stations? For example, are spy satellites perhaps equipped with stealth technology to prevent radar tracking? Or is it pointless as they can always be optically tracked?
coleopterist
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Which operating systems is the International Space Station running?
I've seen some of the articles mention that ISS switched from Windows to Linux. But that's just considering the laptops. What OS are the other computers present on ISS running? I would think that e.g. life support isn't running on a laptop and isn't…
Radek Liska
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