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Astronomy Picture of the Day -- Skylab Over Earth
NASA ^ | August 18, 2013 | (see photo credit)

Posted on 08/18/2013 5:52:51 AM PDT by SunkenCiv

Explanation: Skylab was an orbiting laboratory launched by a Saturn V rocket in May 1973. Skylab, pictured above, was visited three times by NASA astronauts who sometimes stayed as long as two and a half months. Many scientific tests were performed on Skylab, including astronomical observations in ultraviolet and X-ray light. Some of these observations yielded valuable information about Comet Kohoutek, our Sun and about the mysterious X-ray background -- radiation that comes from all over the sky. Skylab fell back to earth on 1979 July 11.

August 18, 2013

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; astronomy; cometkohoutek; nasa; saturnv; science; skylab; xraybackground
[Credit: Skylab, NASA]

1 posted on 08/18/2013 5:52:51 AM PDT by SunkenCiv
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...

Highlights of the 2013 Perseids Meteor Shower
The Big One

2 posted on 08/18/2013 5:54:03 AM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: SunkenCiv

In retrospect I think we should have gone to the moon instead.


3 posted on 08/18/2013 5:57:09 AM PDT by cripplecreek (REMEMBER THE RIVER RAISIN!)
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To: SunkenCiv

I remember SkyLab. It was SO cool at the time...the first orbiting Space Station.

Those were great years, weren’t they!


4 posted on 08/18/2013 6:09:14 AM PDT by left that other site (You Shall Know the Truth, and the Truth Shall Set You Free...John 8:32)
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To: SunkenCiv

I saw Skylab pass over one night. Very neat.


5 posted on 08/18/2013 6:36:18 AM PDT by bigheadfred (INFIDEL)
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To: SunkenCiv

looking at that picture, thats a long way to fall back to earth.

where did it land? anywhere? or did it just incinerate?


6 posted on 08/18/2013 6:48:03 AM PDT by beebuster2000
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To: beebuster2000
Some pieces ended up in Australia if ?I recall correctly
7 posted on 08/18/2013 7:07:54 AM PDT by Conspiracy Guy (To stay calm during these tumultuous times, I take Damitol. Ask your Doctor if it's right for you.)
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To: SunkenCiv

Did Skylab fall out of orbit on its own or did they help it, like by firing retrorockets or something?

I think it would have been cool if it had stayed up there as a historical relic. Imagine boarding it fifty or a hundred years later.


8 posted on 08/18/2013 7:17:18 AM PDT by Yardstick
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To: Yardstick

i dont think it could stay up forever because eventually it runs out of helium so it sinks.


9 posted on 08/18/2013 7:31:38 AM PDT by beebuster2000
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To: Yardstick; beebuster2000

It would descend due to drag. There’s still a thin atmosphere at that altitude. It would need propellant to maintain speed and orbit.


10 posted on 08/18/2013 7:40:16 AM PDT by Moonman62 (The US has become a government with a country, rather than a country with a government.)
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To: beebuster2000

Satellites and space stations stay aloft by orbiting the earth at escape velocity. They are moving so fast that the curved earth literally falls away beneath them faster than gravity can pull them down. It has nothing to do with helium. (Or were you kidding about that?)


11 posted on 08/18/2013 7:46:51 AM PDT by Yardstick
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To: Moonman62

That makes sense. I wish they had given it a nudge to keep it up there.


12 posted on 08/18/2013 7:47:56 AM PDT by Yardstick
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To: Yardstick
-- Satellites and space stations stay aloft by orbiting the earth at escape velocity. They are moving so fast that the curved earth literally falls away beneath them faster than gravity can pull them down. --

A nitpick (but I did like the helium line, somebody has to fall for it), if they were going that fast, they would escape. They are going fast enough so that the earth falls away (due to curvature) at the same rate the satellite would be falling.

I think the international space station (ISS) orbits at about 17,000 MPH, and escape velocity is about 25,000 MPH.

13 posted on 08/18/2013 7:58:36 AM PDT by Cboldt
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To: SunkenCiv

http://www.youtube.com/watch?v=qLoNQNK376E


14 posted on 08/18/2013 8:07:15 AM PDT by Toddsterpatriot (Science is hard. Harder if you're stupid.)
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To: Cboldt

I left out that detail for simplicity’s sake but thanks for filling it in. So I guess that pretty much everything up there, unless it’s moving at precisely the velocity that would keep it in perfect orbit, is either spiraling towards or away from earth, and therefore doomed to become either Skylab or Major Tom eventually.


15 posted on 08/18/2013 8:37:28 AM PDT by Yardstick
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To: Yardstick
-- I guess that pretty much everything up there, unless it's moving at precisely the velocity that would keep it in perfect orbit, is either spiraling towards or away from earth ... --

I think an object can spiral away but not escape (not moving fast enough), so after spiraling away for awhile, it reverses and spirals toward. Either it's moving fast enough, or it's Skylab. Might take a few hundred thousand years ;-)

16 posted on 08/18/2013 9:18:56 AM PDT by Cboldt
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To: Cboldt

Hmm, maybe an object can only spiral away if it’s accelerating — i.e. gaining kinetic energy. Which would mean an unpowered object like a satellite or space station could only spiral inward, though perhaps losing altitude at a very slow rate. The presence of any drag at all, even from a few air molecules here and there, would keep the case of maintaining a fixed orbit from being possible. Does this geekery sound legit to you? :-)


17 posted on 08/18/2013 10:21:33 AM PDT by Yardstick
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To: Yardstick
-- Which would mean an unpowered object like a satellite or space station could only spiral inward ... Does this geekery sound legit to you? --

Yep. Spiraling out takes energy. While higher orbits require lower orbital velocity, it takes quite a bit of energy to elevate.

I'm sure I've misled as to escape velocity though. That 25,000 MPH is if the object is launched from the earth's surface, then loses propulsion (at low altitude). The farther away the object is from the earth, the lower the escape velocity, gravity is weaker as distance increases. I don;t know the relationship between escape velocity and orbital velocity ... maybe they are very close to the same value.

18 posted on 08/18/2013 11:02:27 AM PDT by Cboldt
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To: Yardstick
-- Which would mean an unpowered object like a satellite or space station could only spiral inward ... Does this geekery sound legit to you? --

Yep. Spiraling out takes energy. While higher orbits require lower orbital velocity, it takes quite a bit of energy to elevate.

I'm sure I've misled as to escape velocity though. That 25,000 MPH is if the object is launched from the earth's surface, then loses propulsion (at low altitude). The farther away the object is from the earth, the lower the escape velocity, gravity is weaker as distance increases. I don;t know the relationship between escape velocity and orbital velocity ... maybe they are very close to the same value.

19 posted on 08/18/2013 11:02:31 AM PDT by Cboldt
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To: SunkenCiv

When taking tennis lessons at the time, the instructor liked to employ the “Skylob” ...


20 posted on 08/18/2013 11:36:58 AM PDT by mikrofon (Passing shot ;)
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To: beebuster2000; Yardstick

Part of it landed in my mailbox — I got a poster around here (somewhere) with a photo of Skylab in orbit, and attached is a plastic pouch containing a sliver of the fiberglas (?) tank that managed to survive reentry and land in the the Outback I think it was. Most of the rest of it burned up.

After it had been basically derelict for a few years, NASA’s plan to resume using it via trips aboard the Space Shuttle fell apart because the Shuttle was years behind schedule. NATURALLY (and it’s just like is going on now) the previous orbital technology had been discontinued first.

That’s part of the gubmint manual, under the heading, “Not Learning From Our Mistakes” with some citations of the “Who Gives a Damn What We Do Around Here As Long as the Check Clears” appendix.

The communications technology was from the Gemini program, because both Skylab and Gemini were orbital vehicles. The Gemini comm network was purpose-built, whereas the Mercury comm network had been ad hoc (as quite realistically portrayed in “The Right Stuff”).

One person was put in charge of keeping the Skylab aloft until the the Shuttle was ready. He found out that the Skylab didn’t respond to transmissions, and it was reasonable to assume that the automated systems had failed to (or been unable to) maintain the onboard batteries.

His solution was to send the same commands over and over at the same rate that the onboard computer ran through its check to see if there was sufficient battery power to maintain the comm connection (this isn’t remotely anything they’d planned for). This way the cycle was keeping the charging process going by continuously sending the command to do that. The system would start charging, the computer would look at the batteries, see that they were too low, and shut down the circuitry that was doing the charging.

Yes, it is a gov’t operation, why do you ask?

The guy kept this up whenever the Skylab was both in comm range and in such a place that the solar panels were pumping out juice.

After *that* process, the computer would be turned on and would use the still-operational rockets on board to push the Skylab up into a higher orbit.

Then the orbital path would spend a few days or so out of comm range, the batteries would run down, and the whole process would start again.

Anyway, this heroic improvisation kept the Skylab aloft an extra few years, until the fuel nearly ran out and the Shuttle was still not ready. So his last task was to get the batteries charged again and do the controlled deorbit over the Indian Ocean where least chance of damage was.


21 posted on 08/18/2013 4:10:16 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: left that other site; bigheadfred

They were, and those were just the tail-end of the great years. It puts things into perspective, for example, that the 150 ton Skylab was put into orbit (LEO) in one shot, aboard the last of the Saturn V’s ever launched. The modules for the ISS (what a stupid name) are about 20 tons each, what a joke.

I remember watching Skylab go over a few times, and how enormous the dot was.


22 posted on 08/18/2013 4:14:11 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: SunkenCiv

I remember the Gemini program with great fondness. How many kids today even KNOW what that was?


23 posted on 08/18/2013 4:16:14 PM PDT by left that other site (You Shall Know the Truth, and the Truth Shall Set You Free...John 8:32)
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To: cripplecreek

“Been there, done that.” :’) I think we should have put a base on the Moon, right at the far edge of the near side, and maintained crews there; ultimately we should have a far side observation station (it could be 100 percent automated now, with a cable across the landscape to the link station on the near side) where there’s zero interference from the Earth.

Also, Von Braun’s plan was to use multiple launches of the Saturn V to assemble a Mars mission in orbit (he thought it would take about 12 launches for each Mars mission), and to go by 1986. That would have been a hell of a lot better than blowing up and burning up people with the STS, and accomplishing nothing in orbit that can’t already be done robotically.


24 posted on 08/18/2013 4:18:57 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: Toddsterpatriot

;’)


25 posted on 08/18/2013 4:19:04 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: left that other site

That was the program that a lot of the early astronauts liked the best, as the craft was designed to the requirements of the men who were going to fly it. I’ve read that Grissom in particular had a lot to say about it, and those who flew it could tell it was a pilot’s machine.

That superb design philosophy survived in some fashion into the Apollo design, y’know, other than that little mishap where the shitty Apollo 1 ignited inside and burned those three astronauts to death.

Von Braun was a fanatic about safety; the Mercury missions were a gamble because the boosters were pretty iffy. But Gemini was used to provide practical experience in rendezvous and docking — both needed for the Apollo missions still on the drawing board — and reentry (ditto).

The first three Apollo missions were more of the same; Apollo 8 took a similar weighted chunk of ballast to simulate the lunar module; 9 went only to Earth orbit, but practiced with the actual lunar module; 10 took the module to the Moon, and practiced everything including descent but then just dropped the legs and went back up to the Command Module. They practiced the maneuvers needed for the later missions, to test both the hardware and the execution.

Space walks were practiced by the Soviet cosmonauts because their lunar missions involved nearly simultaneous launches of two vehicles — one would have taken two cosmonauts into lunar orbit, where they’d rendezvous with the unmanned lander vehicle sent by the other launch. Since they didn’t have room in their mass budget for a docking module, the lucky solo cosmonaut would leave the craft, make a space walk over to the lander, get in, turn on, drop down, get out, plant the flag, make a broadcast, get back in the craft, take off from the surface, rendezvous, make another space walk, get back into the return vehicle, and return to Earth with the other cosmonaut.

The N1 boosters to be used for this never had a successful flight test, and actually never had their engine clusters systematically tested either — the clusters were built and shipped, then installed. The first N1 test destroyed the entire launchpad, one of the two needed for the lunar mission, and due to budget shifts (part of Korolev’s budget was shifted to Gluschko) it was never rebuilt.


26 posted on 08/18/2013 4:35:12 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: SunkenCiv
John Belushi gave a great presentation regarding the crash of Skylab.


27 posted on 08/18/2013 4:38:53 PM PDT by Larry Lucido
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To: SunkenCiv

A polar station on the moon would have been a good place to start. If we could man a station on the moon for 20 or 30 years, we could damn sure do a permanent major Martian station.

Getting to Mars is hard but staying should be technically easier. Mars isn’t a hard vacuum. Temperatures fluctuate widely but not nearly as wide as the moon. The day night cycle of mars isn’t two weeks long. Radiation levels on Mars are elevated but not incredibly high and sheltering underground is likely anyway. Tougher to get off the surface of mars than the moon but easier than earth.

Get a couple thousand people on the moon and maybe 10,000 the mars working toward building heavy lift vehicles that will then work on carrying parts to Martian orbit for serious ships to mine asteroids etc. Then then the surface of mars would become primarily a habitat.

If I had the world’s resources at my disposal I would like to put a transparent dome over one of those stadium sized Martian craters as a big ass greenhouse.


28 posted on 08/18/2013 4:39:33 PM PDT by cripplecreek (REMEMBER THE RIVER RAISIN!)
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To: SunkenCiv

The first “Docking” was an amazing event. I’ll never forget how exciting it was for me.

The first spacewalk by an American was Astronaut Edward White. Which was EXTREMELY cool because that was my little brother’s name too.


29 posted on 08/18/2013 4:53:31 PM PDT by left that other site (You Shall Know the Truth, and the Truth Shall Set You Free...John 8:32)
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To: Yardstick

Even in orbit, there is some air, even though it’s so thin it’s virtually non-existent. However, it’s enough to provide the drag that eventually caused Skylab to fall out of orbit. It was uncontrolled, and crashed somewhere off New Zealand, I believe. It was quite an event, and there were warnings along the crash line. There have been other notable dangerous deorbits.

An important lesson was learned: If a satellite is inserted into orbit, a means must be provided to fire engines to slow it down and crash in a controlled manner, into an ocean somewhere. In fact, for private ventures, the companies that fly the birds have to have the money in escrow at launch time, in addition to the propellant on board the crafts, to properly deorbit them.

I worked for the company that put the Iridium system into orbit to service world-wide telephones (call ‘em satellite phones). The system when belly up, so the plan to deorbit was put into play. It was already paid for. I don’t know what eventually happened to Iridium, because my section of the company left that section. It might have been sold before they crashed the birds, I don’t know. There were dozens or satellites, IIRC.


30 posted on 08/18/2013 5:10:02 PM PDT by Cyber Liberty (It wasn't the Rodeo Clown's act, it was the crowd reaction they could't take.)
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To: cripplecreek
I would like to put a transparent dome over one of those stadium sized Martian craters as a big ass greenhouse.

Better start saving those beer cans.

31 posted on 08/18/2013 6:20:20 PM PDT by bigheadfred (INFIDEL)
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To: SunkenCiv

Wow, very interesting...and talk about a kluge to keep it running. I still think they should have found a way to keep it up there. Somehow the thought of a disco-era derelict being boarded a hundred years from now just seems incredibly eery and cool.

When you say he did a controlled deorbit, how controlled was it? Did they fire retrorockets to bring it down or did they just go with its natural descent and fire side rockets (or whatever they’re called) to steer it?


32 posted on 08/22/2013 9:24:50 PM PDT by Yardstick
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To: SunkenCiv

It was like a trailer in the sky, with a tarp.

Thank goodness no space tornado or sharknado came around


33 posted on 08/22/2013 9:26:21 PM PDT by GeronL
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To: Cyber Liberty

Thanks for the comment, Cyber Liberty. Very interesting.


34 posted on 08/22/2013 9:27:20 PM PDT by Yardstick
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