Communications with Mars

[lamontagne]

What might be the requirements for communications with a large Mars colony?  And how quickly would they be required?  even if there is a time lag and comms are not in real time, would there be a lot of communications to transmit?  Perhaps a large number of high resolution video feeds, for example?

Illustrated here is a large installation in a Lagrange Point, communicating with Mars using a high bandwidth microwave antenna,  and back to Earth with a mid sized antenna.  A number of smaller antennas are tracking various missions.  The whole thing is solar powered, spiderfab build.  The main antenna is 80 m across, while the solar array provides 1 MW of power.  I expect the whole thing could be put in place with a single Spaceship, probably with some refuelling.  Is this reasonable in the context of SpaceX and Spaceship?  Way overkill?  Insufficient?

(Edit):
Here are links to similar threads that I failed to discover earlier.  Sorry.

Topic: SpX Mars Communication Constellation?
https://forum.nasaspaceflight.com/index.php?topic=45483.0

Topic: SpaceX and DSN
https://forum.nasaspaceflight.com/index.php?topic=45256.0

Topic: SpaceX's DSN plans
https://forum.nasaspaceflight.com/index.php?topic=41240.0

Topic: How does SpaceX communicate with their vehicles on orbit (and beyond)?
https://forum.nasaspaceflight.com/index.php?topic=44889

Topic: Martian Communication Networking
https://forum.nasaspaceflight.com/index.php?topic=43389


And a table from the last thread, referring previous threads worth reviewing:

Mars Telecom Orbiter redux
NASA Selects Five Mars Orbiter Concept Studies
Ramifications of a positioning and communications constellation in LMO or MMO

[vaporcobra]

What might be the requirements for communications with a large Mars colony?  And how quickly would they be required?  even if there is a time lag and comms are not in real time, would there be a lot of communications to transmit?  Perhaps a large number of high resolution video feeds, for example?

Illustrated here is a large installation in a Lagrange Point, communicating with Mars using a high bandwidth microwave antenna,  and back to Earth with a mid sized antenna.  A number of smaller antennas are tracking various missions.  The whole thing is solar powered, spiderfab build.  The main antenna is 80 m across, while the solar array provides 1 MW of power.  I expect the whole thing could be put in place with a single Spaceship, probably with some refuelling.  Is this reasonable in the context of SpaceX and Spaceship?  Way overkill?  Insufficient?

With Starlink definitively in SpaceX's R&D pipeline, I think modularity is gonna be both extremely desirable and the lowest-energy path for communications infrastructure. Optical communications will likely also play into any larger or monolithic space-based comms installations.

[lamontagne]

What might be the requirements for communications with a large Mars colony?  And how quickly would they be required?  even if there is a time lag and comms are not in real time, would there be a lot of communications to transmit?  Perhaps a large number of high resolution video feeds, for example?

Illustrated here is a large installation in a Lagrange Point, communicating with Mars using a high bandwidth microwave antenna,  and back to Earth with a mid sized antenna.  A number of smaller antennas are tracking various missions.  The whole thing is solar powered, spiderfab build.  The main antenna is 80 m across, while the solar array provides 1 MW of power.  I expect the whole thing could be put in place with a single Spaceship, probably with some refuelling.  Is this reasonable in the context of SpaceX and Spaceship?  Way overkill?  Insufficient?

With Starlink definitively in SpaceX's R&D pipeline, I think modularity is gonna be both extremely desirable and the lowest-energy path for communications infrastructure. Optical communications will likely also play into any larger or monolithic space-based comms installations.

So an array rather than a single large antenna?

[vaporcobra]

What might be the requirements for communications with a large Mars colony?  And how quickly would they be required?  even if there is a time lag and comms are not in real time, would there be a lot of communications to transmit?  Perhaps a large number of high resolution video feeds, for example?

Illustrated here is a large installation in a Lagrange Point, communicating with Mars using a high bandwidth microwave antenna,  and back to Earth with a mid sized antenna.  A number of smaller antennas are tracking various missions.  The whole thing is solar powered, spiderfab build.  The main antenna is 80 m across, while the solar array provides 1 MW of power.  I expect the whole thing could be put in place with a single Spaceship, probably with some refuelling.  Is this reasonable in the context of SpaceX and Spaceship?  Way overkill?  Insufficient?

With Starlink definitively in SpaceX's R&D pipeline, I think modularity is gonna be both extremely desirable and the lowest-energy path for communications infrastructure. Optical communications will likely also play into any larger or monolithic space-based comms installations.

So an array rather than a single large antenna?

Yeah. If not a constellation with Starlink-class disaggregation, then a sort of dramatically expanded iteration on the Starlink bus to allow for the addition of something like a 50-100 kW Tbps-class satellite whenever new capacity is needed.

I can absolutely see the value of large monolithic stations and in-space infrastructure like what you've visualized, but only decades down the road when a given Mars colony is pushing 1000 colonists and a dozen or more crewed ships per synod.

Just as a tangential example, the most capable GEO communications satellites (Viasat 3) in development will weigh around 7000 kg and should have a throughput of more than 1000 Gbps each. A single satellite (with 1000 Gbps) could easily service 10,000-100,000 extremely heavy users (10-100 Mbps per user, 24/7).

The tech would of course be radically different when you're talking about tens of millions of km vs ~35,000, but < 5-10 satellites with even a ten or hundredfold reduction in bandwidth per kg would more than satisfy SpaceX's deep space comms needs for at least a decade or two.

[guckyfan]

I expect them to use Starlink satellites as a base for development. Mostly replace one of the laser com units of 15cm diameter with one of ~1.5m diameter and probably a higher powered laser.

[lamontagne]

What might be the requirements for communications with a large Mars colony?  And how quickly would they be required?  even if there is a time lag and comms are not in real time, would there be a lot of communications to transmit?  Perhaps a large number of high resolution video feeds, for example?

Illustrated here is a large installation in a Lagrange Point, communicating with Mars using a high bandwidth microwave antenna,  and back to Earth with a mid sized antenna.  A number of smaller antennas are tracking various missions.  The whole thing is solar powered, spiderfab build.  The main antenna is 80 m across, while the solar array provides 1 MW of power.  I expect the whole thing could be put in place with a single Spaceship, probably with some refuelling.  Is this reasonable in the context of SpaceX and Spaceship?  Way overkill?  Insufficient?

With Starlink definitively in SpaceX's R&D pipeline, I think modularity is gonna be both extremely desirable and the lowest-energy path for communications infrastructure. Optical communications will likely also play into any larger or monolithic space-based comms installations.

So an array rather than a single large antenna?

Yeah. If not a constellation with Starlink-class disaggregation, then a sort of dramatically expanded iteration on the Starlink bus to allow for the addition of something like a 50-100 kW Tbps-class satellite whenever new capacity is needed.

I can absolutely see the value of large monolithic stations and in-space infrastructure like what you've visualized, but only decades down the road when a given Mars colony is pushing 1000 colonists and a dozen or more crewed ships per synod.

Just as a tangential example, the most capable GEO communications satellites (Viasat 3) in development will weigh around 7000 kg and should have a throughput of more than 1000 Gbps each. A single satellite (with 1000 Gbps) could easily service 10,000-100,000 extremely heavy users (10-100 Mbps per user, 24/7).

The tech would of course be radically different when you're talking about tens of millions of km vs ~35,000, but < 5-10 satellites with even a ten or hundredfold reduction in bandwidth per kg would more than satisfy SpaceX's deep space comms needs for at least a decade or two.

Oh good, that's exactly the time frame I was thinking about.  10 to fifteen years after the beginning of the colony.
My main antenna is perhaps overkill?  Do communication satellites still use parabolic antennas?  Viasat seems to have a different configuration. 
I guess Mars at 3000 to 6000 times the distance might have very different configuration needs? 

[CuddlyRocket]

First you have to decide what your communication needs will be - present and anticipated - and then you design the communication system to meet those needs in as efficient manner as possible, in relation to financial and other inputs (remembering that manpower and resources will be limited on Mars).

Communications needs are two-fold: on and around Mars and between Mars and Earth.

Considering the latter (as it's the title of the thread!), I think there are two basic questions: Do we need 24/365 communications? Do we need the highest bandwidth at all times?

I don't think there will be many people who will answer 'no' to the first question. And IMO the answer to the second question is also 'no' (most communications will not be time sensitive and most of the crew/colonists will be asleep at night).

I think we can take for granted that communciations will be available at all times of day at full capability from the Earth end. On Mars, I think most of the communications will be handled by a powerful antenna at the base/colony. This will be in operation whenever Earth is in line-of-sight, even at night (NASA's DSN dishes seem to have 20 kW transmitters - which I suspect would be overkill! - so transmitting over a full night would require 240 kWh storage absent nuclear power; and a single Tesla powerpack has 210 kWh).

That leaves the situation when the base/colony is not in line of sight, either because of the planets' rotations or because they're on opposite sides of the Sun. Relay satellites are the obvious solution (the only one for the opposition scenario). Size and capability depends on an assessment of how much time-sensitive communication you actually need, even in an emergency (remembering Apollo 13 was basically dealt with by a single voice channel). In the long term, I expect they'll have additional antennas on Mars - you'd need at least three in total, set 7,000 km apart! (Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

[lamontagne]

First you have to decide what your communication needs will be - present and anticipated - and then you design the communication system to meet those needs in as efficient manner as possible, in relation to financial and other inputs (remembering that manpower and resources will be limited on Mars).

Communications needs are two-fold: on and around Mars and between Mars and Earth.

Considering the latter (as it's the title of the thread!), I think there are two basic questions: Do we need 24/365 communications? Do we need the highest bandwidth at all times?

I don't think there will be many people who will answer 'no' to the first question. And IMO the answer to the second question is also 'no' (most communications will not be time sensitive and most of the crew/colonists will be asleep at night).

I think we can take for granted that communciations will be available at all times of day at full capability from the Earth end. On Mars, I think most of the communications will be handled by a powerful antenna at the base/colony. This will be in operation whenever Earth is in line-of-sight, even at night (NASA's DSN dishes seem to have 20 kW transmitters - which I suspect would be overkill! - so transmitting over a full night would require 240 kWh storage absent nuclear power; and a single Tesla powerpack has 210 kWh).

That leaves the situation when the base/colony is not in line of sight, either because of the planets' rotations or because they're on opposite sides of the Sun. Relay satellites are the obvious solution (the only one for the opposition scenario). Size and capability depends on an assessment of how much time-sensitive communication you actually need, even in an emergency (remembering Apollo 13 was basically dealt with by a single voice channel). In the long term, I expect they'll have additional antennas on Mars - you'd need at least three in total, set 7,000 km apart! (Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?
If we have a single geostationary antenna at Mars, and another one at the Earth,  we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?  This should be fairly simple to do with solar power and an electric thruster?
And weigh about 19 970 tonnes less?

So what are the communication needs?  In the case of a rapidly growing colony of at least 1000 people.  Perhaps that should go in the title of the thread.

From Mars:
-There will be thousands of colonists and their phones, communicating locally, but also sending clips and video feeds home.
-There will be data collecting stations.
-There will be dozens of high resolution video feeds from the surface, Mars weather satellites, exploration teams
-Medical imagery, health monitoring, plus a load of sensor data.
-General Internet traffic.
Towards Mars:
-There will be updates to news feeds.  Wikipedia feeds, Netflix feeds, channel feeds, sports feeds.
-Synchronisation of databases

I have no knowledge in the communication field, but it seems like a lot to me.   And it seems like a lot of data to store and to send in bursts if it can be spread out over the day instead.  Hence the illustrated geostationary antenna.
Is there such a thing as a communication needs calculator?

[Lampyridae]

First you have to decide what your communication needs will be - present and anticipated - and then you design the communication system to meet those needs in as efficient manner as possible, in relation to financial and other inputs (remembering that manpower and resources will be limited on Mars).

Communications needs are two-fold: on and around Mars and between Mars and Earth.

Considering the latter (as it's the title of the thread!), I think there are two basic questions: Do we need 24/365 communications? Do we need the highest bandwidth at all times?

I don't think there will be many people who will answer 'no' to the first question. And IMO the answer to the second question is also 'no' (most communications will not be time sensitive and most of the crew/colonists will be asleep at night).

I think we can take for granted that communciations will be available at all times of day at full capability from the Earth end. On Mars, I think most of the communications will be handled by a powerful antenna at the base/colony. This will be in operation whenever Earth is in line-of-sight, even at night (NASA's DSN dishes seem to have 20 kW transmitters - which I suspect would be overkill! - so transmitting over a full night would require 240 kWh storage absent nuclear power; and a single Tesla powerpack has 210 kWh).

That leaves the situation when the base/colony is not in line of sight, either because of the planets' rotations or because they're on opposite sides of the Sun. Relay satellites are the obvious solution (the only one for the opposition scenario). Size and capability depends on an assessment of how much time-sensitive communication you actually need, even in an emergency (remembering Apollo 13 was basically dealt with by a single voice channel). In the long term, I expect they'll have additional antennas on Mars - you'd need at least three in total, set 7,000 km apart! (Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?
If we have a single geostationary antenna at Mars, and another one at the Earth,  we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?  This should be fairly simple to do with solar power and an electric thruster?
And weigh about 19 970 tonnes less?

So what are the communication needs?  In the case of a rapidly growing colony of at least 1000 people.  Perhaps that should go in the title of the thread.

From Mars:
-There will be thousands of colonists and their phones, communicating locally, but also sending clips and video feeds home.
-There will be data collecting stations.
-There will be dozens of high resolution video feeds from the surface, Mars weather satellites, exploration teams
-Medical imagery, health monitoring, plus a load of sensor data.
-General Internet traffic.
Towards Mars:
-There will be updates to news feeds.  Wikipedia feeds, Netflix feeds, channel feeds, sports feeds.
-Synchronisation of databases

I have no knowledge in the communication field, but it seems like a lot to me.   And it seems like a lot of data to store and to send in bursts if it can be spread out over the day instead.  Hence the illustrated geostationary antenna.
Is there such a thing as a communication needs calculator?

It's pointless to look at present-day needs, but games give us an idea of what's going on with file sizes. In 10 years' time when (hopefully) we'll be printing the first marscrete domes for the Mars colony, games will probably weigh in at a terabyte for a AAA title. Forza Motorsport is already 100GB. 1080p is looking clunky now, so we're moving on to 4K. 10, 20 years from now, you'll be looking at VR games that have 16K textures - 1GB for a single texture panel. That's insane. Developers are also exceedingly lazy at trimming data - games nowadays are chock full of unused artwork, have 10 languages installed even though you'll only ever use one etc etc.

For video, one hour of raw 8K footage weighs in at 7.3TB. That's not just the extra pixels - these file formats are being packed with all sorts of metadata, extra colour range etc.

If you want eye-perfect resolution to completely fill your field of view at >160px per degree, that's about 28K resolution. That's 90TB for an hour's raw video, 180TB to make it 3D. That would be upload for an immersive documentary or something from Mars.

Obviously data will be compressed, cached etc. and the Martians probably will spend a lot less time Netflixing and chilling. But for a daily bandwidth, I think you're looking at several gigabytes per colonist at the very least.

[lamontagne]

First you have to decide what your communication needs will be - present and anticipated - and then you design the communication system to meet those needs in as efficient manner as possible, in relation to financial and other inputs (remembering that manpower and resources will be limited on Mars).

Communications needs are two-fold: on and around Mars and between Mars and Earth.

Considering the latter (as it's the title of the thread!), I think there are two basic questions: Do we need 24/365 communications? Do we need the highest bandwidth at all times?

I don't think there will be many people who will answer 'no' to the first question. And IMO the answer to the second question is also 'no' (most communications will not be time sensitive and most of the crew/colonists will be asleep at night).

I think we can take for granted that communciations will be available at all times of day at full capability from the Earth end. On Mars, I think most of the communications will be handled by a powerful antenna at the base/colony. This will be in operation whenever Earth is in line-of-sight, even at night (NASA's DSN dishes seem to have 20 kW transmitters - which I suspect would be overkill! - so transmitting over a full night would require 240 kWh storage absent nuclear power; and a single Tesla powerpack has 210 kWh).

That leaves the situation when the base/colony is not in line of sight, either because of the planets' rotations or because they're on opposite sides of the Sun. Relay satellites are the obvious solution (the only one for the opposition scenario). Size and capability depends on an assessment of how much time-sensitive communication you actually need, even in an emergency (remembering Apollo 13 was basically dealt with by a single voice channel). In the long term, I expect they'll have additional antennas on Mars - you'd need at least three in total, set 7,000 km apart! (Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?
If we have a single geostationary antenna at Mars, and another one at the Earth,  we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?  This should be fairly simple to do with solar power and an electric thruster?
And weigh about 19 970 tonnes less?

So what are the communication needs?  In the case of a rapidly growing colony of at least 1000 people.  Perhaps that should go in the title of the thread.

From Mars:
-There will be thousands of colonists and their phones, communicating locally, but also sending clips and video feeds home.
-There will be data collecting stations.
-There will be dozens of high resolution video feeds from the surface, Mars weather satellites, exploration teams
-Medical imagery, health monitoring, plus a load of sensor data.
-General Internet traffic.
Towards Mars:
-There will be updates to news feeds.  Wikipedia feeds, Netflix feeds, channel feeds, sports feeds.
-Synchronisation of databases

I have no knowledge in the communication field, but it seems like a lot to me.   And it seems like a lot of data to store and to send in bursts if it can be spread out over the day instead.  Hence the illustrated geostationary antenna.
Is there such a thing as a communication needs calculator?

It's pointless to look at present-day needs, but games give us an idea of what's going on with file sizes. In 10 years' time when (hopefully) we'll be printing the first marscrete domes for the Mars colony, games will probably weigh in at a terabyte for a AAA title. Forza Motorsport is already 100GB. 1080p is looking clunky now, so we're moving on to 4K. 10, 20 years from now, you'll be looking at VR games that have 16K textures - 1GB for a single texture panel. That's insane. Developers are also exceedingly lazy at trimming data - games nowadays are chock full of unused artwork, have 10 languages installed even though you'll only ever use one etc etc.

For video, one hour of raw 8K footage weighs in at 7.3TB. That's not just the extra pixels - these file formats are being packed with all sorts of metadata, extra colour range etc.

If you want eye-perfect resolution to completely fill your field of view at >160px per degree, that's about 28K resolution. That's 90TB for an hour's raw video, 180TB to make it 3D. That would be upload for an immersive documentary or something from Mars.

Obviously data will be compressed, cached etc. and the Martians probably will spend a lot less time Netflixing and chilling. But for a daily bandwidth, I think you're looking at several gigabytes per colonist at the very least.

100 TB per hour is 30 Gbps.  I've joined a spreadsheet developed by one of my friends for another project,  that gives me 10 Gbps for a 80m antenna.
Hum, do I need more power?

[glennfish]

First you have to decide what your communication needs will be - present and anticipated - and then you design the communication system to meet those needs in as efficient manner as possible, in relation to financial and other inputs (remembering that manpower and resources will be limited on Mars).

Communications needs are two-fold: on and around Mars and between Mars and Earth.

Considering the latter (as it's the title of the thread!), I think there are two basic questions: Do we need 24/365 communications? Do we need the highest bandwidth at all times?

I don't think there will be many people who will answer 'no' to the first question. And IMO the answer to the second question is also 'no' (most communications will not be time sensitive and most of the crew/colonists will be asleep at night).

I think we can take for granted that communciations will be available at all times of day at full capability from the Earth end. On Mars, I think most of the communications will be handled by a powerful antenna at the base/colony. This will be in operation whenever Earth is in line-of-sight, even at night (NASA's DSN dishes seem to have 20 kW transmitters - which I suspect would be overkill! - so transmitting over a full night would require 240 kWh storage absent nuclear power; and a single Tesla powerpack has 210 kWh).

That leaves the situation when the base/colony is not in line of sight, either because of the planets' rotations or because they're on opposite sides of the Sun. Relay satellites are the obvious solution (the only one for the opposition scenario). Size and capability depends on an assessment of how much time-sensitive communication you actually need, even in an emergency (remembering Apollo 13 was basically dealt with by a single voice channel). In the long term, I expect they'll have additional antennas on Mars - you'd need at least three in total, set 7,000 km apart! (Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?
If we have a single geostationary antenna at Mars, and another one at the Earth,  we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?  This should be fairly simple to do with solar power and an electric thruster?
And weigh about 19 970 tonnes less?

So what are the communication needs?  In the case of a rapidly growing colony of at least 1000 people.  Perhaps that should go in the title of the thread.

From Mars:
-There will be thousands of colonists and their phones, communicating locally, but also sending clips and video feeds home.
-There will be data collecting stations.
-There will be dozens of high resolution video feeds from the surface, Mars weather satellites, exploration teams
-Medical imagery, health monitoring, plus a load of sensor data.
-General Internet traffic.
Towards Mars:
-There will be updates to news feeds.  Wikipedia feeds, Netflix feeds, channel feeds, sports feeds.
-Synchronisation of databases

I have no knowledge in the communication field, but it seems like a lot to me.   And it seems like a lot of data to store and to send in bursts if it can be spread out over the day instead.  Hence the illustrated geostationary antenna.
Is there such a thing as a communication needs calculator?

It's pointless to look at present-day needs, but games give us an idea of what's going on with file sizes. In 10 years' time when (hopefully) we'll be printing the first marscrete domes for the Mars colony, games will probably weigh in at a terabyte for a AAA title. Forza Motorsport is already 100GB. 1080p is looking clunky now, so we're moving on to 4K. 10, 20 years from now, you'll be looking at VR games that have 16K textures - 1GB for a single texture panel. That's insane. Developers are also exceedingly lazy at trimming data - games nowadays are chock full of unused artwork, have 10 languages installed even though you'll only ever use one etc etc.

For video, one hour of raw 8K footage weighs in at 7.3TB. That's not just the extra pixels - these file formats are being packed with all sorts of metadata, extra colour range etc.

If you want eye-perfect resolution to completely fill your field of view at >160px per degree, that's about 28K resolution. That's 90TB for an hour's raw video, 180TB to make it 3D. That would be upload for an immersive documentary or something from Mars.

Obviously data will be compressed, cached etc. and the Martians probably will spend a lot less time Netflixing and chilling. But for a daily bandwidth, I think you're looking at several gigabytes per colonist at the very least.

100 TB per hour is 30 Gbps.  I've joined a spreadsheet developed by one of my friends for another project,  that gives me 10 Gbps for a 80m antenna.
Hum, do I need more power?

IMHO video density is going to plateau in much the same way CPU clock speeds plateaued about 8 years ago.  It get's more difficult over time to go faster without a breakthrough or advanced need.  Display resolutions requiring such high density at some point can be measured by their waste rather than resolution.

I can picture surcharges for high resolution video in the next few years and definitely if you have small pipes like for interplanetary traffic.

No one really needs the 8k plus resolution.  see: https://carltonbale.com/home-theater/home-theater-calculator/

[Robotbeat]

VR does.

VR content definitely benefits from 8K resolution.

[launchwatcher]

(Deep sea fibre optic cable masses 1.4 tons/km, so you'd need ~20,000 tons of such cable - very long term!)

I think you can do a lot better than that mass-wise.   

On the surface you don't need to resist the pressure of miles of water overhead, and you don't need to carry power from the ends of the cable for optical amplifiers - periodic relay stations with local solar power and batteries should do the trick.

First spec I found for armored cable for surface use was a mere 10% of the weight -- 144kg/km for up to 72 fibers, and you could undoubtedly go below that if you don't need as many fibers.

Even terrestrial direct-burial cable may be overengineered for Mars -- one of the main reasons for armored fiber optic cable on earth is to resist rodent damage.

[lamontagne]

So here is a little article about 8K UHDTV.

https://www.extremetech.com/extreme/130238-8k-uhdtv-how-do-you-send-a-48gbps-tv-signal-over-terrestrial-airwaves

I'm taking from it that a single  8K signal, once compressed, is 500 Mbps, so my 10 Gbps would be good for 20 channels or so.
Somehow I feel 10 Gbps is, possibly, a little tight. 

[CuddlyRocket]

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?

Why do we have three DSN stations when we can have relay satellites in Earth orbit? Basically, size and power. Though I was thinking long-term at that point at which future time I assumed there'd be bases or colonies around the planet. This wouldn't be the communications structure for a small single colony.

If we have a single geostationary antenna at Mars, and another one at the Earth, we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?

Single geostationary satellites wouldn't allow for 24/365 communications as they'd be out of line-of-sight at certain times, though not for as long as ground-based antennas. I'd also be reluctant to rely on single satellites - redundancy is comforting!

[lamontagne]

Why do we need more than one ground station on Mars if we can, and need, to have relay satellites in orbit?

Why do we have three DSN stations when we can have relay satellites in Earth orbit? Basically, size and power. Though I was thinking long-term at that point at which future time I assumed there'd be bases or colonies around the planet. This wouldn't be the communications structure for a small single colony.

If we have a single geostationary antenna at Mars, and another one at the Earth, we probably need a single other relay satellite somewhere in a solar orbit, either in a lead or lag position?

Single geostationary satellites wouldn't allow for 24/365 communications as they'd be out of line-of-sight at certain times, though not for as long as ground-based antennas. I'd also be reluctant to rely on single satellites - redundancy is comforting!

Yes, so redundant ground bases and redundant satellites? 
With SpaceX capabilities, wouldn't a  few large orbital satellites in Mars orbit be cheaper than a few large ground stations?  And avoid transmission losses through Mars atmosphere (although that may be a non issue)
And won't solar power be more available in Mars orbit anyway, so if the solar arrays come from Earth, kJ of communications for kJ of communication at MArs an orbital station is better than a ground station?  guess this falls through if we have nuclear power on the ground though.

And what about launching the satellite in Earth orbit and using its large solar arrays to power an electric engine, so it can drive itself to Mars?  And to any other required way stations?

I am supposing something like spiderfabs from Tethers Unlimited to manufacture a very light and large antenna.  This could only be done in space.  The technology would be useful for communications towards Earth as well, perhaps?  Or for space based radio telescopes.

[biosehnsucht]

Somewhere back in the Starlink threads there was discussion about using nearly "off the shelf" starlink satellites (minimal modification) creatively to solve the Earth-Mars communication issue.

I don't recall the math but someone determined that you could essentially use multiple lasers (via multiple starlink sats) in parallel in both directions rather than RF for some tremendous bandwidth. One of the gotchas was that these planet to planet satellites would need to be visually far enough away from their respective planets that the laser receivers could easily detect the inbound lasers without being swamped with the reflected light of the planets they're orbiting (so only satellites on the periphery as seen by the other planet could be used to send, but any facing the planet could be used to receive).

At the interplanetary distances involved the laser beam widths would spread to be quite large, which would make acquisition of signal easier than one might first assume.

TL;DR "phased array" style laser comms using many starlink sats as elements in a virtual "antenna" instead of a single RF antenna with many elements

[ThereIWas3]

I am not sure that "phased array" techniques at optical frequencies over large distances with moving platforms is at a technical readiness level at all feasible.

[Cinder]

I am not sure that "phased array" techniques at optical frequencies over large distances with moving platforms is at a technical readiness level at all feasible.

(Naive question)  would a long string of repeaters on a cycler pattern work? 
Would solar be good enough to keep them alive for some preliminary period (<10yrs of first Mars ops)?
Does the expense of most sats idling till they're between Earth and Mars again make it unfeasible?

[lamontagne]

Somewhere back in the Starlink threads there was discussion about using nearly "off the shelf" starlink satellites (minimal modification) creatively to solve the Earth-Mars communication issue.

I don't recall the math but someone determined that you could essentially use multiple lasers (via multiple starlink sats) in parallel in both directions rather than RF for some tremendous bandwidth. One of the gotchas was that these planet to planet satellites would need to be visually far enough away from their respective planets that the laser receivers could easily detect the inbound lasers without being swamped with the reflected light of the planets they're orbiting (so only satellites on the periphery as seen by the other planet could be used to send, but any facing the planet could be used to receive).

At the interplanetary distances involved the laser beam widths would spread to be quite large, which would make acquisition of signal easier than one might first assume.

TL;DR "phased array" style laser comms using many starlink sats as elements in a virtual "antenna" instead of a single RF antenna with many elements

I think you mean microwave phased array and not laser?  Everything else works.  Perhaps starlink got crossed with Starshot, that is a phased array laser design?
Formation flying might be required for this and I'm not certain it's simpler than a large antenna.  Moving the starlink satellites to a higher orbit may be just as complex as a single large antenna.  The phased array is fun because it's electronic aiming and doesn't need mechanical parts (I think) but are there communication gains?

Tethers Unlimited would be so happy to have a 80m antenna to build!