Author Topic: Real-time earth-view satellite network  (Read 9679 times)

Offline PeterAlt

  • Full Member
  • ****
  • Posts: 720
  • West Palm Beach, FL
  • Liked: 8
  • Likes Given: 40
Real-time earth-view satellite network
« on: 02/20/2012 10:58 pm »
I remember the first time seeing Google Earth and wondering if there would ever be a time when we could get live satellite images and see ourselves waiving at the satellite. Then, when I considered how many satellites this would require, I gave up hope that this would ever happen in our lifetimes...

...until now. The key to making this work is to use ultra-small "micro
satellites" containing only very basic electronics. Each would contain an imaging camera with the ultra macro lensing system required, gyroscopes to keep its orbit from decaying, and wireless communication systems for communication with the satellites on either side of its orbit. It would simply be a small ball, in both shape and size. Its exterior shell would be covered with photovoltaic conducive material, effectively acting as a single solar energy cell. Each would carry a small rocket motor with enough fuel to make it to the "next" orbital position of the network in solar-synchronous orbit and for eventual deorbiting (or it could use electric propulsion).

The network could be launched in sections. A single launch could carry many multiples of these micro satellites. The satellites could launch chained together like a train. At the first orbital position for the first micro satellite, the first satellite is released. The propulsion on the next micro satellite propels the remaining satellites in the chain to the next orbital slot, where it would release the next satellite. This would continue until each micro satellite is released.

The satellites would pass data wirelessly to the next closest satellite on either side of the orbital network until the data reaches one of the few satellites in the network equipped with earth-relay communications systems. The system doesn't have to have continuous live service (in order to reduce costs by using fewer satellites), but spaced just enough to "feel" like it's live...
« Last Edit: 02/20/2012 11:25 pm by PeterAlt »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37441
  • Cape Canaveral Spaceport
  • Liked: 21451
  • Likes Given: 428
Re: Real-time earth-view satellite network
« Reply #1 on: 02/20/2012 11:08 pm »
I remember the first time seeing Google Earth and wondering if there would ever be a time when we could get live satellite images and see ourselves waiving at the satellite. Then, when I considered how many satellites this would require, I gave up hope that this would ever happen in our lifetimes...

...until now. The key to making this work is to use ultra-small "micro
satellites" containing only very basic electronics. Each would contain an imaging camera with the ultra macro lensing system required, gyroscopes to keep its orbit from decaying, and wireless communication systems for communication with the satellites on either side of its orbit. It would simply be a small ball, in both shape and size. Its

No, it is not now or ever

A.  gyroscopes don't  keep satellites in  orbit, they only point spacecraft

b.  they can't be small, there is a fixed aperture size to get the resolution to see a person.

c.  Same goes for the field of view, either more spacecraft or larger spacecraft

d.  Speaking of the number of spacecraft, it would be in the 1000's or more to get the instantaneous coverage

e.  Collecting the data from all these spacecraft would implausible and actually might be enough to overwhelm the internet

Offline PeterAlt

  • Full Member
  • ****
  • Posts: 720
  • West Palm Beach, FL
  • Liked: 8
  • Likes Given: 40
Re: Real-time earth-view satellite network
« Reply #2 on: 02/20/2012 11:27 pm »
Not that it would make your answer any different, but I accidentally uploaded the post as I was in the middle of typing it. I edited the post and replaced it with the completed version.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8823
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1318
  • Likes Given: 306
Re: Real-time earth-view satellite network
« Reply #3 on: 02/21/2012 05:30 pm »
Aaah, Gore-Sat reborn in LEO.

You might want to look at the history of Gore-Sat (... eeer Triana, now I believe is being reborn from the ashes like a phoenix, renamed DSCOVR being refurbished to monitor space weather, and set to possibly fly in 2014.) 
If you're happy and you know it,
It's your med's!

Offline Zond

  • Member
  • Full Member
  • **
  • Posts: 228
  • Liked: 56
  • Likes Given: 1
Re: Real-time earth-view satellite network
« Reply #4 on: 02/21/2012 06:55 pm »
Quote
By delivering the first live, continuous, true color image stream of Earth from space, AstroVision will revolutionize the delivery of weather, news, and environmental information.
http://www.astrovision.com/ourbus.html

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 39270
  • Minnesota
  • Liked: 25240
  • Likes Given: 12115
Re: Real-time earth-view satellite network
« Reply #5 on: 02/21/2012 07:02 pm »
*shrug* I'm not so sure this is that difficult in a less ambitious form. A cubesat with an aperture of 10cm in diameter could possibly get up to around 2-5 meters resolution, depending on the altitude and wavelength. You wouldn't get real-time, but you might be able to get hourly with a constellation...

Though the best way to do this would probably be a constellation of large satellites in MEO. GSO satellites with very large apertures could get essentially real-time views of an entire region, though you're really probably going to run into bandwidth limitations at that point (30 Gigabytes for a single 24-bit color image of a 1000km by 1000km region taken by a ~5m aperture at GSO with ~5m of resolution... 35 Terabytes per image of the entire disc of the Earth taken at ~3m resolution...a lot less compressed, obviously).

You're talking around a Petabyte per second of uncompressed data if you are looking at the whole surface of the Earth in real-time at 3m resolution (less near the poles) at 10 frames per second in color, taken from 3 different satellites in GSO.

EDIT: And I doubt that 8 bits per channel would be nearly good enough because of the enormous dynamic range of the Earth, so multiply the above data rate figures by 2 to get 16 bits per channel.
« Last Edit: 02/21/2012 07:04 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 10390
  • Lansing MI
  • Liked: 1415
  • Likes Given: 171
Re: Real-time earth-view satellite network
« Reply #6 on: 02/21/2012 07:03 pm »
That's great - "live" weather? Sheez...

Offline ugordan

  • Senior Member
  • *****
  • Posts: 8520
    • My mainly Cassini image gallery
  • Liked: 3543
  • Likes Given: 759
Re: Real-time earth-view satellite network
« Reply #7 on: 02/21/2012 07:12 pm »
EDIT: And I doubt that 8 bits per channel would be nearly good enough because of the enormous dynamic range of the Earth, so multiply the above data rate figures by 2 to get 16 bits per channel.

8 bits can be adequate if you use lookup tables to encode more bits (usually 12).

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 39270
  • Minnesota
  • Liked: 25240
  • Likes Given: 12115
Re: Real-time earth-view satellite network
« Reply #8 on: 02/21/2012 07:36 pm »
EDIT: And I doubt that 8 bits per channel would be nearly good enough because of the enormous dynamic range of the Earth, so multiply the above data rate figures by 2 to get 16 bits per channel.

8 bits can be adequate if you use lookup tables to encode more bits (usually 12).
Agree. It can be argued that's a form of lossy compression, though (so is everything, I suppose!).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15391
    • Space Launch Report
  • Liked: 8566
  • Likes Given: 1356
Re: Real-time earth-view satellite network
« Reply #9 on: 02/21/2012 08:24 pm »
Why a new satellite network?  Here's a complete image of our hemisphere taken by GOES East less than an hour ago.
http://wwwghcc.msfc.nasa.gov/GOES/goeseastfull.html

 - Ed Kyle

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 10390
  • Lansing MI
  • Liked: 1415
  • Likes Given: 171
Re: Real-time earth-view satellite network
« Reply #10 on: 02/21/2012 08:42 pm »
Check the website - that's not live :)

Offline DarkenedOne

  • Full Member
  • ****
  • Posts: 955
  • Liked: 58
  • Likes Given: 9
Re: Real-time earth-view satellite network
« Reply #11 on: 02/21/2012 08:50 pm »
I remember the first time seeing Google Earth and wondering if there would ever be a time when we could get live satellite images and see ourselves waiving at the satellite. Then, when I considered how many satellites this would require, I gave up hope that this would ever happen in our lifetimes...

...until now. The key to making this work is to use ultra-small "micro
satellites" containing only very basic electronics. Each would contain an imaging camera with the ultra macro lensing system required, gyroscopes to keep its orbit from decaying, and wireless communication systems for communication with the satellites on either side of its orbit. It would simply be a small ball, in both shape and size. Its

No, it is not now or ever

A.  gyroscopes don't  keep satellites in  orbit, they only point spacecraft

b.  they can't be small, there is a fixed aperture size to get the resolution to see a person.

c.  Same goes for the field of view, either more spacecraft or larger spacecraft

d.  Speaking of the number of spacecraft, it would be in the 1000's or more to get the instantaneous coverage

e.  Collecting the data from all these spacecraft would implausible and actually might be enough to overwhelm the internet

Jim is pretty much right as usual.  However there are a few things.

b.  Dawes limit does impose resolution restrictions on a single telescope for a given size, however that does not apply to arrays of telescopes, aka. an interferometer. 

e.  You cannot overwhelm the internet.  The internet is a network of networks.  It is limited by the connection speed between networks and computers. 
 

Offline DarkenedOne

  • Full Member
  • ****
  • Posts: 955
  • Liked: 58
  • Likes Given: 9
Re: Real-time earth-view satellite network
« Reply #12 on: 02/21/2012 08:59 pm »
Also to make it more realistic live coverage of certain regions would be very useful, but the vast majority of Earth's surface is not worth it.  Remember 70% of the globe is ocean.  Going beyond that humans inhabit only a small part.

Offline PeterAlt

  • Full Member
  • ****
  • Posts: 720
  • West Palm Beach, FL
  • Liked: 8
  • Likes Given: 40
Re: Real-time earth-view satellite network
« Reply #13 on: 02/22/2012 12:46 am »
Also to make it more realistic live coverage of certain regions would be very useful, but the vast majority of Earth's surface is not worth it.  Remember 70% of the globe is ocean.  Going beyond that humans inhabit only a small part.

Yes, good point. The system could begin by covering major metropolitan areas at first and expand to more areas over time...

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15391
    • Space Launch Report
  • Liked: 8566
  • Likes Given: 1356
Re: Real-time earth-view satellite network
« Reply #14 on: 02/22/2012 12:50 am »
Check the website - that's not live :)

Not live of course, but fresh images every three hours.  That's "live-enough", isn't it, to show cloud movements and day/night terminators?  What else is there to see from space, that can be reasonably seen, that needs to be "live"?

 - Ed Kyle

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37441
  • Cape Canaveral Spaceport
  • Liked: 21451
  • Likes Given: 428
Re: Real-time earth-view satellite network
« Reply #15 on: 02/22/2012 02:17 am »
Also to make it more realistic live coverage of certain regions would be very useful, but the vast majority of Earth's surface is not worth it.  Remember 70% of the globe is ocean.  Going beyond that humans inhabit only a small part.

Yes, good point. The system could begin by covering major metropolitan areas at first and expand to more areas over time...

Huh?  The idea is not viable so there are no changes to improve it.  Anyways, it doesn't reduce the number spacecraft needed,  it only reduces the amount of data being downlinked.  Example, the 24 spacecraft GPS constellation was based on always having 3-4 spacecraft in view for most of the earth's surface.  Even if the oceans were eliminated, the constellation would stay the same. 

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 10390
  • Lansing MI
  • Liked: 1415
  • Likes Given: 171
Re: Real-time earth-view satellite network
« Reply #16 on: 02/22/2012 02:58 am »
Check the website - that's not live :)

Not live of course, but fresh images every three hours. 

The US is updated every 15 minutes (5 during active weather.) My point was that the website says it offers "live weather" as a major selling point for that commercial venture. All it would show you is clouds. And at that range, you aren't going to know the difference in what it shows "live" versus a 15 minute old GOES image.

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 10974
  • Delta-t is an important metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 1257
  • Likes Given: 724
Re: Real-time earth-view satellite network
« Reply #17 on: 02/23/2012 01:28 pm »
In a way, it's a cool idea, but it immediately brings to mind Big Brother spying on everyone who is outdoors.
Sometimes I just flat out don't get it.

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0