Deep Space Industries vs Planetary Resources

[Robotbeat]

mlinder: I believe it. But just /having/ a listed price is a pretty big improvement, IMHO, over regular spacecraft parts. The magnetic torquers definitely don't /have/ to cost that much (reaction wheels are a little tougher, though... harder to DIY).

[JohnFornaro]

You're equating mass and/or size with capability without understanding what drives the requirements for size.

No. 

I'm not seeing any propellant in it, and once the LV sends it from Earth to point A, I don't see it really ever getting to a possible point B.

That's the "capability" I keep harping on.

Hayabusa weighed 510kg wet, and 380kg dry.  That mission lasted for seven years.  True, it brought back a sample.

The cubesats from DSI and PRI are rather tiny, even if they're not scheduled to make a round trip.

I'm not believing what I hear yet.

They would use cubesat components and design philosophy.

Well of course, in general.

I'm still not believing in what I hear yet.  The cubesats are too small to have the broad capability that is necessary.

[JohnFornaro]

Having worked in development of some of the above, the listed prices are very inflated compared to the actual costs of production of those devices.

Apparently, SpaceX has found a similar inflation in the list price of a rocket launch.

[JohnFornaro]

Communication:
1 ) For the laser communication system what is the foot print size of the beam sent from Earth and received at Mars?

Mining:
2 ) Could they bag the NEA, heat it up ...

Reuse and refueling:
With the mind gas they should be able to ... deliver the raw material to the processors or customers.

1) How do they get the laser signal out of the Earth's atmosphere, and back thru it?  How do they accomodate the Earth's rotation?  Either that, or, where is the LEO or GEO comm system?  DSN doesn't use lasers, BTW.

2) Not with cubesats.

3) The gas is all in the mind, of course.  At least that part's easy.

[JohnFornaro]

The cubesat shop.

Totally excellent.

[JohnFornaro]

... just because larger spacecraft are usually used doesn't mean it is impossible to do it smaller.

Which is fine, but neither does it mean that it's possible either.

[JohnFornaro]

DSI, if they have 20 people for 3 years that build and operate their 3 cubesats then would be a cost of ~$12M.

You only need 2-3 people to operate a cubesat mission, their complexity is quite low.

That may be, but hea said, "build and operate".  The business plan which has them build a fleet of two sats, and then lay off the builders, is not really the plan of a sustainable company.

[douglas100]

1) How do they get the laser signal out of the Earth's atmosphere, and back thru it?  How do they accomodate the Earth's rotation?  Either that, or, where is the LEO or GEO comm system?  DSN doesn't use lasers, BTW.

The signal would come to what would be essentially an astronomical telescope. So you would not have com in daylight or if it's cloudy. This limits your options. You might have telescopes at several clear weather sites around the world to increase your chances.

As far as the Earth's rotation is concerned, that's almost trivial. The telescope (either altazimuth or polar mounted) would track the spacecraft as it would track any other object on the celestial sphere, turning to counteract the Earth's rotation. The DSN antennas do the same thing.

As you mention, you could get round the difficulties with the Earth's atmosphere by having the receiving telescope in space. Operationally the best place would probably be GSO. That would mean you would only need one ground station. The receiving telescope could point to any part of the celestial sphere that's not too close to the sun and get the laser signal unaffected by the atmosphere. The last part of the signal's journey would be by radio to the ground station.

That option would be expensive, of course, but technically doable.

[Robotbeat]

... just because larger spacecraft are usually used doesn't mean it is impossible to do it smaller.

Which is fine, but neither does it mean that it's possible either.

It IS possible to do recon with a cubesat, end of story. Whether they can do it cheaply and quickly is not a settled question.

You can do Earth observation from a cubesat. You can do it in infrared, you can even do spectroscopy from a cubesat. Simply being able to map out the asteroid would be quite useful, and there's no real good reason you couldn't do it from a cubesat platform (data rate may be an issue).

The big question is figuring out how to do deep space operations with a cubesat. They can already operate and maneuver in LEO, but deep space has higher communication issues.


Planetary believes they can solve the issue by using the telescope to do laser comms. This isn't unreasonable. They can do laser-comms between LEO Arkyds and deep space Arkyds, communicating between LEO and the ground either through gaps in the clouds (data rate would be very high) or simply through radio.

[mlindner]

Communication:
1 ) For the laser communication system what is the foot print size of the beam sent from Earth and received at Mars?

Mining:
2 ) Could they bag the NEA, heat it up ...

Reuse and refueling:
With the mind gas they should be able to ... deliver the raw material to the processors or customers.

1) How do they get the laser signal out of the Earth's atmosphere, and back thru it?  How do they accomodate the Earth's rotation?  Either that, or, where is the LEO or GEO comm system?  DSN doesn't use lasers, BTW.

2) Not with cubesats.

3) The gas is all in the mind, of course.  At least that part's easy.

1) Lasers have constant angular beam diameter set by the dispersion rate of the beam (assuming a vacuum). I would guess that the diameter of the beam from earth to Mars even at closest approach would be greater than the diameter of the entire planet. Hitting the target isn't so much of an issue IMO than getting the dispersion low enough to have high enough power density at the receiving point.

[JohnFornaro]

As far as the Earth's rotation is concerned, that's almost trivial.

You misunderstand me.  I quite realize that telescopes can track objects.  The Earth's rotation will determine the number of probably tracking stations.  Neither of these companies has made any public statements as to how they will pragmatically communicate with their cubesats.

To date, most terrestrial telescopes are passive receivers of information and observations, not transmitters thereof.

That option [GSO or GEO comm station] would be expensive, of course, but technically doable.

Think it thru a mite longer.  All they are stressing is that they can make cheap cubesats from OTS components, and that they have a "secret sauce" that enables more capabilities than hitherto demonstrated for communicating with those sats.

... just because larger spacecraft are usually used doesn't mean it is impossible to do it smaller.

Which is fine, but neither does it mean that it's possible either.

It IS possible to do recon with a cubesat, end of story. Whether they can do it cheaply and quickly is not a settled question.

You can do Earth observation from a cubesat....

Of course it's possible to observe the Earth.  That is not their main objective.

The big question is figuring out how to do deep space operations with a cubesat. They can already operate and maneuver in LEO, but deep space has higher communication issues.

What they've said so far doesn't sound like it's possible to me.  Are you on their board?  You keep banging the drum that what they assert is "technically" possible.

Planetary believes they can solve the issue by using the telescope to do laser comms. This isn't unreasonable. They can do laser-comms between LEO Arkyds and deep space Arkyds, communicating between LEO and the ground either through gaps in the clouds (data rate would be very high) or simply through radio.

Of course they have what you and they assert; not unreasonable assertions.  Now I gotta channel QuantumG:

There is no true Scotsman.

[JohnFornaro]

Communication:
1 ) For the laser communication system what is the foot print size of the beam sent from Earth and received at Mars?

1) How do they get the laser signal out of the Earth's atmosphere, and back thru it?  How do they accomodate the Earth's rotation?  Either that, or, where is the LEO or GEO comm system?  DSN doesn't use lasers, BTW.

1) Lasers have constant angular beam diameter set by the dispersion rate of the beam (assuming a vacuum). I would guess that the diameter of the beam from earth to Mars even at closest approach would be greater than the diameter of the entire planet. Hitting the target isn't so much of an issue IMO than getting the dispersion low enough to have high enough power density at the receiving point.

The relationship between dispersion and power density is exactly the issue I was getting at.  The solar array that is illustrated for the cubesat looks pretty small to be powering and flying the sat, and having enough "oomf" to get a decent signal back to Earth.

Even tho the beam is as wide as the Earth, that angle of dispersion is pretty darn small when you're looking from that sat back to the pinprick of light that is the Earth.  You, or they, will have to aim pretty darn accurately.  Which I assume is "technically" doable, even tho no such demonstration mission has taken place at the present time.

They appear to be asserting that they will solve this communications challenge on the first try.  An investor is supposed to believe that assertion.

[Robotbeat]

Communication:
1 ) For the laser communication system what is the foot print size of the beam sent from Earth and received at Mars?

Mining:
2 ) Could they bag the NEA, heat it up ...

Reuse and refueling:
With the mind gas they should be able to ... deliver the raw material to the processors or customers.

1) How do they get the laser signal out of the Earth's atmosphere, and back thru it?  How do they accomodate the Earth's rotation?  Either that, or, where is the LEO or GEO comm system?  DSN doesn't use lasers, BTW.

2) Not with cubesats.

3) The gas is all in the mind, of course.  At least that part's easy.

1) Lasers have constant angular beam diameter set by the dispersion rate of the beam (assuming a vacuum). I would guess that the diameter of the beam from earth to Mars even at closest approach would be greater than the diameter of the entire planet. Hitting the target isn't so much of an issue IMO than getting the dispersion low enough to have high enough power density at the receiving point.

The beam size is essentially the same size as the smallest discernible feature in a telescope the same aperture. You can see features on Mars from Earth on a telescope smaller than the one Planetary Resources is using, so they should be able to do pretty well.

(Note: this is just because I'm too lazy to do the Rayleigh criterion equation which is basically: half-angle-in-radians-of-beam=1.22*aperturediameter/(wavelengthoflightused) )

[douglas100]

From John Fornaro:

To date, most terrestrial telescopes are passive receivers of information and observations, not transmitters thereof.

(my bold)
Bear in mind that it's the downlink where a high rate is an advantage. The uplink would be mostly command files and the like. It doesn't need an optical transmitter. Ordinary radio should do just fine.

[mlindner]

The relationship between dispersion and power density is exactly the issue I was getting at.  The solar array that is illustrated for the cubesat looks pretty small to be powering and flying the sat, and having enough "oomf" to get a decent signal back to Earth.

Even tho the beam is as wide as the Earth, that angle of dispersion is pretty darn small when you're looking from that sat back to the pinprick of light that is the Earth.  You, or they, will have to aim pretty darn accurately.  Which I assume is "technically" doable, even tho no such demonstration mission has taken place at the present time.

They appear to be asserting that they will solve this communications challenge on the first try.  An investor is supposed to believe that assertion.

Cubesats run quite power negative when transmitting even at very low power with radios so this is no surprise. This is what batteries are for. I haven't seen numbers for laser data transmission, but I would assume it's significantly better.

They already have their investors, so they're currently believing them or at least believing their credentials (which are quite good).

I should note as well no telescope is needed on the ground for data transmission to an LEO satellite. Granted some better equipment and higher flash and modulation rates are needed, but this was done with a tiny off the shelf consumer laser pointer and a standard consumer camera.
See http://www.universetoday.com/93987/amateur-astronomers-flash-the-space-station/
"When the spotlights were off, he said he could still see the [1 Watt] blue laser, which was shone steadily,"

[Robotbeat]

The relationship between dispersion and power density is exactly the issue I was getting at.  The solar array that is illustrated for the cubesat looks pretty small to be powering and flying the sat, and having enough "oomf" to get a decent signal back to Earth.

Even tho the beam is as wide as the Earth, that angle of dispersion is pretty darn small when you're looking from that sat back to the pinprick of light that is the Earth.  You, or they, will have to aim pretty darn accurately.  Which I assume is "technically" doable, even tho no such demonstration mission has taken place at the present time.

They appear to be asserting that they will solve this communications challenge on the first try.  An investor is supposed to believe that assertion.

Cubesats run quite power negative when transmitting even at very low power with radios so this is no surprise. This is what batteries are for. I haven't seen numbers for laser data transmission, but I would assume it's significantly better.

They already have their investors, so they're currently believing them or at least believing their credentials (which are quite good).

I should note as well no telescope is needed on the ground for data transmission to an LEO satellite. Granted some better equipment and higher flash and modulation rates are needed, but this was done with a tiny off the shelf consumer laser pointer and a standard consumer camera.
See http://www.universetoday.com/93987/amateur-astronomers-flash-the-space-station/
"When the spotlights were off, he said he could still see the [1 Watt] blue laser, which was shone steadily,"

This video is great for showing the sort of thing Planetary Resources is thinking about:

[A_M_Swallow]

From John Fornaro:

To date, most terrestrial telescopes are passive receivers of information and observations, not transmitters thereof.

(my bold)
Bear in mind that it's the downlink where a high rate is an advantage. The uplink would be mostly command files and the like. It doesn't need an optical transmitter. Ordinary radio should do just fine.

Using lasers to give orders to the satellite is inadvisable because the sun will frequently be behind the Earth.  Pointing ordinary telescopes at the sun tends to damage light detectors.

[JohnFornaro]

...The solar array that is illustrated for the cubesat looks pretty small to be powering and flying the sat, and having enough "oomf" to get a decent signal back to Earth.

Even tho the beam is as wide as the Earth, ... they will have to aim pretty darn accurately.  Which I assume is "technically" doable, even tho no such demonstration mission has taken place at the present time.

They appear to be asserting that they will solve this communications challenge on the first try.  An investor is supposed to believe that assertion.

Cubesats run quite power negative when transmitting even at very low power with radios so this is no surprise. This is what batteries are for. I haven't seen numbers for laser data transmission, but I would assume it's significantly better.

What comes as no surprise?  That they're going to do it right the first time?  Also, what does "power negative" mean in this context?  The only thing generating electricity up there is the solar panels.

As to laser data transmission rates, I don't know the specifics of their system, since it appears to be proprietary.  I do know that high rates of data transmission across the laboratory do not translate into the same rates of data transmission between the asteroid belt and Earth, particularly when the two are in opposition.  Even so, the video that Chris posted was pretty cool.

They already have their investors, so they're currently believing them or at least believing their credentials (which are quite good).

That's true, they have said that they "already have investors".  They did not say that they don't need any more.  It should be clear, with a bit of reflection, that I was referring to the investors that they'd like to convince.  Right now, I would hold on to my million dollar investment, based on their public statements, and my assessment of their success based on those statements.

I should note as well no telescope is needed on the ground for data transmission to an LEO satellite. ...

Another reminder that I am discussing the communication power cababilities of the cubesat, particularly when it is at opposition.

[Rugoz]

Bringing 1 kilogram from an asteroid back to earth (landing incl.) must already cost more than 50k, right? (50k is the price of 1kg of platinum)

Then you still haven't done any mining, which probably would require tons of equipment for extracting precious metals, unless there are asteroids made of pure platinum floating around in space.

Regarding water mining. Well that certainly sounds easier, however it would require a significant human presence in space in the forseeable future. That could be due to some utterly expensive government program (like the ISS), which would be good for business, however if a massive reduction in launch costs is behind it, bringing in water from asteroids could become less attractive.

[mlindner]

What comes as no surprise?  That they're going to do it right the first time?  Also, what does "power negative" mean in this context?  The only thing generating electricity up there is the solar panels.

In spacecraft mission ops, missions have various "modes" of operation and each has an associated power use rate. This is all labeled out in the power budget during the design phase of the mission (and refined as construction/testing proceeds). Several modes are often "power negative" in the sense that if you leave your spacecraft in that mode over a given orbit (averaged across the orbit eclipse/non-eclipse periods) then you will have a net drain on your battery.

In this sense whenever they are transmitting they will be very power negative. Basically aggregated over all your orbits, this just constrains your maximum average data transmission rate, even though in brief bursts you will have much higher data transmission rates. You are only limited by the short circuit current of your battery (although in reality you want to be significantly below this as it burns out your battery).

This may be the same for full size spacecraft as well, but in well designed cubesats almost all the subsystems are completely powered down when they are not active and they often have several super low power modes beyond that.

As to laser data transmission rates, I don't know the specifics of their system, since it appears to be proprietary.  I do know that high rates of data transmission across the laboratory do not translate into the same rates of data transmission between the asteroid belt and Earth, particularly when the two are in opposition.  Even so, the video that Chris posted was pretty cool.

I agree, lab rates do not correlate to reality. That is what testbed spacecraft are for though, which is what they are working on currently.

The video is from the page I linked in the post above which has a lot more info about how it was done and some of the specifics. So I suggest you take a look at that as well.