Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

Post your random pics!

Gabe

Well-known member
Joined
Jan 10, 2015
Messages
1,189
Likes
301
Points
83
Too cool thx LC Always wondered and yes im going to get drilled for this question but is it the earths rotation that makes the shuttle travel at 17,500 mph or the shuttles engines once in orbit?:yabbem:
Once the station/shuttle takes off, the trajectory curves more and more horizontally, until all of that thrust is directed into travelling parallel to the earths surface. Eventually it's moving so fast that the earths curvature makes the ground fall away from the craft just as fast as the craft falls down towards the surface, this means it's in orbit. Since its's so high up, there is hardly any atmosphere to slow its movement down, there's practically no wind resistance to slow its velocity. So the station maintains the speed it had gained from those rockets at the very beginning, for a very long time. There still is some wind resistance, so there are small boosters on the space station that point directly downwards, so when the station slows and its altitude falls, the boosters are turned on and it pushes it back up into a higher orbit. Those boosters also help the station avoid space debris every now and then.
 

Laser Chick

Well-known member
Joined
Jan 26, 2015
Messages
1,266
Likes
181
Points
63
Good Lord. I keep trying to give out Rep+ to about 10 different members and it keeps telling me I have to spread the love around first. Exactly how much do I have to spread myself around?!? Geesh!!! :wtf:
 

micheal rosen

Active member
Joined
Mar 22, 2015
Messages
578
Likes
104
Points
43
Too cool thx LC Always wondered and yes im going to get drilled for this question but is it the earths rotation that makes the shuttle travel at 17,500 mph or the shuttles engines once in orbit?:yabbem:
Part of it is the earth's rotation. The shuttle goes up, and it bascically "falls over" while going up, and then keeps accelerating and turning to the horizon until it is horizontal, then it uses the thrusters to push it until it reaches orbital velocity. The earth's rotation helps, and supplies a couple hundred m/s but the engines provide about 80-90% of the orbital velocity.
 
Last edited:

Gabe

Well-known member
Joined
Jan 10, 2015
Messages
1,189
Likes
301
Points
83
Good Lord. I keep trying to give out Rep+ to about 10 different members and it keeps telling me I have to spread the love around first. Exactly how much do I have to spread myself around?!? Geesh!!! :wtf:
Ikr?i don't think I've repped you in a long while but it still says I need to sprinkle the rep dust around some more! I've had to keep up a rep-owing list for a while. Might be time to change the limit now that fewer people are active here.
 

Laser Chick

Well-known member
Joined
Jan 26, 2015
Messages
1,266
Likes
181
Points
63
I hear ya. I have tried to Rep+ at least 10 to 12 good posts in the last several days and it has been a no go. I guess I will have to spread the love even more so that when a real good post pops up I can jump on it and give it some love <3
 

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,484
Likes
1,335
Points
113
Micheal, Gabe, LC, Thx for explanations I can imagine with just about zero wind resistance once propelled into it would just keep going. Only the few "for now" have only experienced it.
Yes its really hard to give some rep to some really good posts but we can thank them verbally as that makes me feel a bit better.
 

diachi

Well-known member
Joined
Feb 22, 2008
Messages
9,447
Likes
1,322
Points
113
Here's a cool graph showing the altitude of the ISS over the course of a year. You can see where it gradually slows down, thus lowering in altitude, then where it boosts back up to a higher orbit.

 

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,484
Likes
1,335
Points
113
Im guessing the ISS is mostly stationary other than boosting it up from time to time so how fast is the earths rotation in terms of speed. Diachi Do you know why its orbit is 350km or around 220 miles up?
 
Joined
May 14, 2013
Messages
3,798
Likes
505
Points
0
Ok just to clarify some details here, the ISS doesn't have any booster rockets, it's orbit decays about 50 to 100 meters a day, this will increase in the future because it's orbit will probably not be maintained beyond 2020. When it drops below 200 miles it will be abandoned for safety reasons. They used to use the space shuttles and the European Space Agency Automated Transfer Vehicle (ATV) and the Russian Progress vehicles that resupply the ISS. The space shuttles and the ATV are no longer in service, currently the ISS is only boosted by the Russians.

Russia will stop its ISS activities in 2020 in response to U.S. sanctions over Russia's annexation of Crimea. They have also forbidden the ISS from flying over Ukraine after 2020. They were planning to keep it operational until 2024, but now it will likely be abandoned in 2020 and they will attempt a controlled deorbit. The Chinese Tiangong Space Station will probably launch in 2020, and that will be the only place for astronauts to go.

Alan
 

diachi

Well-known member
Joined
Feb 22, 2008
Messages
9,447
Likes
1,322
Points
113
Im guessing the ISS is mostly stationary other than boosting it up from time to time so how fast is the earths rotation in terms of speed. Diachi Do you know why its orbit is 350km or around 220 miles up?
The ISS moves at 7.66kms - or roughly 17,000MPH, it completes an orbit of the earth every 90 minutes or so. The Earth rotates at just over 1,000MPH. So the ISS definitely isn't stationary. It's relatively stationary if you are looking at it vertically, it only moves downwards by around 100m a day - as Alan said.

The altitude chosen is most likely to do with what the space shuttle was capable of. Going higher reduces how large your payload can be and makes the orbit generally harder to reach. I imagine they picked that altitude for the ISS because the orbit decays relatively slowly compared to a lower orbit, and it's also an easier altitude to reach (Than one higher up) with a decent sized payload. The highest the shuttle ever went was a little over 600km on the mission that deployed the Hubble telescope. That said, this is all a guess - I'm not a rocket scientist! :D
 

RB astro

Super Moderator
Staff member
Joined
Apr 6, 2014
Messages
2,453
Likes
1,312
Points
113
Great discussion on the ISS guys !
Thought I'd share a couple of my early attempts at capturing the fly-overs.
These were back in 2008 when I wanted to try out my new Fisheye lens.

The first one took place in late twilight while the moon was bright so as I was doing this long exposure I got a lovely washed out sky scene.




The second was during a "no moon" clear night.
This is a 194 sec exp (3.2 min) capturing the complete horizon to horizon event.

To the right of the ISS flight path you can see our galaxy's (Milky Way) galactic plane stretching from top to bottom, hence the name.

Notice those two little 'fluffy white cloudy patches" in the upper left.
Those are two whole other galaxies outside our own called the Large Magellanic Cloud (LMC) and The Small Magellanic Cloud (SMC) and they stand out so beautifully in my area, even to the naked eye.
Named after the famous explorer Ferdinand Magellan, when he sighted the LMC and SMC on his Southern voyage in 1519 from The Northern Hemisphere.
The galaxies now bear his name although they were know prior to his voyage, as far back as 964 AD.





Hope you enjoy.

RB
:beer:
 

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,484
Likes
1,335
Points
113
RB, diachi, Pi, anybody? I saw the ISS by the naked eye roughly 4 years ago and it wasn,t a fly by. It was dark early morning around 6:00AM, the moon was bright. It just looked like a stationary light well below the stars. It maby took about an hour til I lost sight of it but it was more or less a stationary light. The local news that I saw later that morning did mention it was over are area.:whistle:
 

micheal rosen

Active member
Joined
Mar 22, 2015
Messages
578
Likes
104
Points
43
RB, diachi, Pi, anybody? I saw the ISS by the naked eye roughly 4 years ago and it wasn,t a fly by. It was dark early morning around 6:00AM, the moon was bright. It just looked like a stationary light well below the stars. It maby took about an hour til I lost sight of it but it was more or less a stationary light. The local news that I saw later that morning did mention it was over are area.:whistle:
Then you didn't see the ISS. It moves across the sky quite quickly.
 

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,484
Likes
1,335
Points
113
Then you didn't see the ISS. It moves across the sky quite quickly.
I dont know what else to say or think, I had pointed it out to few people and they saw it but im the one who said that I believed it was the ISS. No flashy lights just a kinda rectangular white light that hovered with a tiny movement of the clouds passing below. It was like I mentioned 4 or so years ago and thats just about how I remember it. Maby it was more like 15 or 20 minutes than an hour before I lost track of it but it was definitely not moving quickly.
 




Top