Author Topic: Diamandis and Simonyi Planetary Resources Company Announcement and Notes  (Read 227307 times)

Offline Danderman

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Let me provide a synopsis of those links:

1 That PR will be orbiting hundreds of these small telescope.

2 That there is some really big market for Earth observations imagery, accessible to PR.

3 That the satellites can be handed over to customers at $2 million a pop

4 There are many customers for telescopes at $2 million a pop.

I don't want to get into the weeds here, but the above assertions are probably far from true.  For example, a big piece of the Earth resources market is for multispectral imagery in specific formats that PR is unlikely to be able to provide. If their little satellites are somehow configured to provide LandSat class sensors, they won't cost $2 million a pop.


Offline Danderman

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A lot of cheap space telescopes will enable disruption of satellite imaging and satellite data markets.

Please explain how a cheap space telescope provides LandSat class multi-spectral imagery.

Offline Danderman

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It would be great if someone here could compare and contrast the Arkyd telescopes with those used on ISS by the crew to image the Earth.

Online jongoff

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It would be great if someone here could compare and contrast the Arkyd telescopes with those used on ISS by the crew to image the Earth.

I think PR's competition is more with SkyBox imaging than with ISS or the bigger earth observation satellites.

~Jon

Offline rklaehn

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A lot of cheap space telescopes will enable disruption of satellite imaging and satellite data markets.

Please explain how a cheap space telescope provides LandSat class multi-spectral imagery.

Revisit time is also very important. There is an entire class of data analysis methods that are only viable with low revisit time.

One of the initial customers might be google. A fleet of LEO telescopes would enable them to completely reimage the earth once per week.

The real interesting question is how they intend to get all that data down. Reading between the lines I think they plan to use the telescope as a laser communications terminal. That would be the only method that would allow data downlink with the required rate given the design of the satellite (no prominent high-gain antenna). It would also be very useful for the second and third generation satellites that fly to actual asteroids.

I am working on the TerraSAR-X / TanDEM-X SAR earth observation project, and I can tell you that downlink bandwith is a major limiting factor for the amount of datatakes you can do.

Offline Danderman

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It would be great if someone here could compare and contrast the Arkyd telescopes with those used on ISS by the crew to image the Earth.

I think PR's competition is more with SkyBox imaging than with ISS or the bigger earth observation satellites.

~Jon

My point is that the focal lengths of the Arkyd telescopes seem to be similar to the ISS photography lenses. I could be wrong on that, but my recollection is that the ISS telescopes used by the crew are close to a meter in length.

One could argue that the PR telescopes will be operating in a very low orbit, and thus have greater resolution than the ISS telescopes, but this begs the question of how the PR telescopes get piggyback rides to very low orbits.

For that matter, exactly which current systems offer piggybag rides to LEO?  Which launch vehicles offer rides that would put the telescopes into "constellations" as described by others here?

« Last Edit: 04/27/2012 02:54 pm by Danderman »

Offline Danderman

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I am working on the TerraSAR-X / TanDEM-X SAR earth observation project, and I can tell you that downlink bandwith is a major limiting factor for the amount of datatakes you can do.

That's an interest point that most people miss; is this due to Tandem not being able to access a sufficient number of ground stations - is that a programatic or technical problem?

Offline rklaehn

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I am working on the TerraSAR-X / TanDEM-X SAR earth observation project, and I can tell you that downlink bandwith is a major limiting factor for the amount of datatakes you can do.

That's an interest point that most people miss; is this due to Tandem not being able to access a sufficient number of ground stations - is that a programatic or technical problem?


It's an economic problem. Of course you could get sufficient bandwidth by booking lots of ground stations. But that costs a lot of money.

During a LEOP (launch and early orbit phase), usually many ground stations all over the world are booked because you want to be in contact with your satellite as often as possible. But for an earth observation program with a duration of many years that would be prohibitively expensive. So DLR is using its own groundstations like Weilheim, or establish new ones like the one in inuvik http://en.wikipedia.org/wiki/Inuvik.

There is also the issue of how you get the data once it is on the ground. Some ground stations are so remote that the data has to be stored on tape and then transported via helicopter and ship, like this one: http://en.wikipedia.org/wiki/Base_General_Bernardo_O'Higgins_Riquelme

Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.

Offline go4mars

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Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.
Maybe it would be laser communication between these things.  Whichever ones happen to be near a cloudless ground receiver are the ones that communicate down for the ones that can't. 
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Offline Danderman

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I am working on the TerraSAR-X / TanDEM-X SAR earth observation project, and I can tell you that downlink bandwith is a major limiting factor for the amount of datatakes you can do.

That's an interest point that most people miss; is this due to Tandem not being able to access a sufficient number of ground stations - is that a programatic or technical problem?


It's an economic problem. Of course you could get sufficient bandwidth by booking lots of ground stations. But that costs a lot of money.

I would like to translate this programmatic problem for a real life spacecraft project (Tandem) to the current question of PR making a lot of money off its proposed constellation of small telescopes. As you know, high resolution imagery requires extremely high bandwidth data rates. Quick return of the data requires a lot of ground stations.

High bandwidth + quick return = lots of ground stations.

On the other hand, returning images of NEOs is not time sensitive and probably not that data intensive.


Offline go4mars

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High bandwidth + quick return = lots of ground stations.

On the other hand, returning images of NEOs is not time sensitive and probably not that data intensive.
How expensive and complex are laser communication receivers?  Would the cost come down per unit a lot if they were mass-produced? 
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Danderman

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Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.
Maybe it would be laser communication between these things.  Whichever ones happen to be near a cloudless ground receiver are the ones that communicate down for the ones that can't. 

If you invoking intersatellite links for these "affordable" small satellites, you might as well suggest that each one will carry its own pony, too.


The ability to transmit laser signals is not the same as being able to receive laser signals. Sending down a laser signal to a ground station a few hundred miles away is different than sending a laser signal to another satellite that might be thousands of miles away.

Offline rklaehn

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Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.
Maybe it would be laser communication between these things.  Whichever ones happen to be near a cloudless ground receiver are the ones that communicate down for the ones that can't. 

You still need many laser communications groundstations to handle the raw amount of data. So you might as well have more on-board storage and downlink directly.

Earth has a land area of 148,940,000,000,000 m^2. Even if you image it in a relatively low resolution of 1m with 24 Bit/Pixel, and you want monthly updates, that is a constant data rate of ~1 GBit/s. But you don't get constant contact with low-flying satellites.

I am not saying that this is impossible. Far from it. But it requires a major infrastructure investment.

Offline Robotbeat

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It would be great if someone here could compare and contrast the Arkyd telescopes with those used on ISS by the crew to image the Earth.

I think PR's competition is more with SkyBox imaging than with ISS or the bigger earth observation satellites.

~Jon

My point is that the focal lengths of the Arkyd telescopes seem to be similar to the ISS photography lenses. I could be wrong on that, but my recollection is that the ISS telescopes used by the crew are close to a meter in length.

One could argue that the PR telescopes will be operating in a very low orbit, and thus have greater resolution than the ISS telescopes, but this begs the question of how the PR telescopes get piggyback rides to very low orbits.

For that matter, exactly which current systems offer piggybag rides to LEO?  Which launch vehicles offer rides that would put the telescopes into "constellations" as described by others here?


Aperture, not focal length, is the limiting factor for resolution.

I don't believe the ISS scopes have as large of aperture. Or rather, they're comparable. Besides, it's likely these will be cheaper.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Robotbeat

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Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.
Maybe it would be laser communication between these things.  Whichever ones happen to be near a cloudless ground receiver are the ones that communicate down for the ones that can't. 

If you invoking intersatellite links for these "affordable" small satellites, you might as well suggest that each one will carry its own pony, too.


The ability to transmit laser signals is not the same as being able to receive laser signals. Sending down a laser signal to a ground station a few hundred miles away is different than sending a laser signal to another satellite that might be thousands of miles away.

The ability to do both is one of their key innovations. They have a contract with NASA on the subject, actually.
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 Danderman

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It would be great if someone here could compare and contrast the Arkyd telescopes with those used on ISS by the crew to image the Earth.

I think PR's competition is more with SkyBox imaging than with ISS or the bigger earth observation satellites.

~Jon

My point is that the focal lengths of the Arkyd telescopes seem to be similar to the ISS photography lenses. I could be wrong on that, but my recollection is that the ISS telescopes used by the crew are close to a meter in length.

One could argue that the PR telescopes will be operating in a very low orbit, and thus have greater resolution than the ISS telescopes, but this begs the question of how the PR telescopes get piggyback rides to very low orbits.

For that matter, exactly which current systems offer piggybag rides to LEO?  Which launch vehicles offer rides that would put the telescopes into "constellations" as described by others here?


Aperture, not focal length, is the limiting factor for resolution.

I don't believe the ISS scopes have as large of aperture. Or rather, they're comparable. Besides, it's likely these will be cheaper.

You are correct. The ISS scopes do not have quite the aperture of the Arkyd scopes, using eyeball measurements. The Arkyrd telescopes have a 9 inch aperture, I believe, whereas the ISS scopes have maybe half that. By "ISS scopes" I mean the lenses used for cameras that the crew uses to image the ground.

Offline go4mars

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If you invoking intersatellite links for these "affordable" small satellites, you might as well suggest that each one will carry its own pony, too.
I have a disproportionate reaction when pony and unicorn types of comparisons get made on here.  I prefer statements like, "that's currently unlikely because X" or "that is against the laws of physics".  Comparison to a little kids desires for a pony or a unicorn is at best rude and discourages further conversation or education.

The ability to transmit laser signals is not the same as being able to receive laser signals. Sending down a laser signal to a ground station a few hundred miles away is different than sending a laser signal to another satellite that might be thousands of miles away.
Perhaps the earlier systems would always have another satellite within an appropriate communication range.  What are the limitations on intersatellite links?  How would more distant "interceptor" versions that go to NEO's be assumed to communicate their findings and photos?   I need to do some reading on laser communication receivers.  Any recommended sources?  Or should I just google?
« Last Edit: 04/27/2012 03:46 pm by go4mars »
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Offline rklaehn

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If you invoking intersatellite links for these "affordable" small satellites, you might as well suggest that each one will carry its own pony, too.
I have a disproportionate reaction when pony and unicorn types of comparisons get made on here.  I prefer statements like, "that's currently unlikely because X" or "that is against the laws of physics".  Comparison to a little kids desires for a pony or a unicorn is at best rude and discourages further conversation or education.

The ability to transmit laser signals is not the same as being able to receive laser signals. Sending down a laser signal to a ground station a few hundred miles away is different than sending a laser signal to another satellite that might be thousands of miles away.
Perhaps the earlier systems would always have another satellite within an appropriate communication range.  What are the limitations on intersatellite links?  How would more distant "interceptor" versions that go to NEO's be assumed to communicate their findings and photos?   I need to do some reading on laser communication receivers.  Any recommended sources?  Or should I just google?

Well, nothing regarding laser communication is physically impossible. TanDEM-X and TerraSAR-X both have a laser communications terminal which is both sender and receiver. The european artemis experimental communications satellite also has a LCT, so they did some experiments with transmitting data from TerraSAR-X to Artemis via Laser and then to the ground using a traditional Ku-Band(?) transmission.

A future european relay satellite constellation called EDRS (like TDRS, just for europe :-) ) is going to have LCTs as well.

The thing is that laser communications is not as commercial off the shelf as Ku- or Ka-Band communications. You can get an entire Ka-Band groundstation by just clicking a few boxes on a website and forking over a seven-figure amount of euros.

Laser communication on the other hand is still kind of experimental. The closest you can get to commercial off the shelf is a german company called tesat-spacecom http://www.tesat.de/ , which builds both satellite terminals and groundstations.
http://www.tesat.de/index.php?option=com_content&view=article&id=64&Itemid=60&lang=en

But for a company like planetary resources that does not have the pressure to make a buck in the next decade or more, bidirectional laser communication is definitely the way to go, especially if cheap communication over interplanetary distances is the long-term goal.
« Last Edit: 04/27/2012 04:02 pm by rklaehn »

Offline Robotbeat

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Laser groundstations would be a good way to get sufficient downstream bandwidth, but you do need many of them spread over a large area because obviously they are useless if you have cloud cover.
Maybe it would be laser communication between these things.  Whichever ones happen to be near a cloudless ground receiver are the ones that communicate down for the ones that can't. 

You still need many laser communications groundstations to handle the raw amount of data. So you might as well have more on-board storage and downlink directly.

Earth has a land area of 148,940,000,000,000 m^2. Even if you image it in a relatively low resolution of 1m with 24 Bit/Pixel, and you want monthly updates, that is a constant data rate of ~1 GBit/s. But you don't get constant contact with low-flying satellites.

I am not saying that this is impossible. Far from it. But it requires a major infrastructure investment.
They're not likely to get full resolution of the whole land area. But perhaps the entire US or Europe.

1Gbit/s isn't necessarily the limit, either. There are already commercial solutions for 2Gbit/s or perhaps even 10Gbit/s open-air laser communication. Remember, the whole point of the laser communication method is very high bandwidth. And after all, you'd have a fleet of these satellites, each capable of high speed communication of around a Gigabit/s. Plus, compression can help as well.

If you were to cover the whole US once every month, that's only an average bandwidth of 10Mbps. All of Europe would be another ~10Mbps. Two orders of magnitude less than a plausible first-generation data rate for free space laser communications.
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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 savuporo

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All right, you need a pretty good pointing accuracy on the sender side for sat to sat laser comms. Which is harder if both the sender and receiver are whizzing about ~8km/s on differing orbits.
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