Could “live” video be transmitted from Mars?
up vote
10
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With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm wondering if the technology to broadcast live video actually exists, if there was a camcorder on one of the missions already at Mars. Could live video be transmitted (IE, is there a capability to get the required bandwidth at a distance of Mars)
If not, then what would it take to make this actually happen?
mars communication video bandwidth
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
add a comment |
up vote
10
down vote
favorite
With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm wondering if the technology to broadcast live video actually exists, if there was a camcorder on one of the missions already at Mars. Could live video be transmitted (IE, is there a capability to get the required bandwidth at a distance of Mars)
If not, then what would it take to make this actually happen?
mars communication video bandwidth
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
2
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
4
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
1
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago
add a comment |
up vote
10
down vote
favorite
up vote
10
down vote
favorite
With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm wondering if the technology to broadcast live video actually exists, if there was a camcorder on one of the missions already at Mars. Could live video be transmitted (IE, is there a capability to get the required bandwidth at a distance of Mars)
If not, then what would it take to make this actually happen?
mars communication video bandwidth
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm wondering if the technology to broadcast live video actually exists, if there was a camcorder on one of the missions already at Mars. Could live video be transmitted (IE, is there a capability to get the required bandwidth at a distance of Mars)
If not, then what would it take to make this actually happen?
mars communication video bandwidth
mars communication video bandwidth
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
edited 9 hours ago
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
asked 13 hours ago
PearsonArtPhoto♦
78.5k16220430
78.5k16220430
2
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
4
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
1
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago
add a comment |
2
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
4
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
1
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago
2
2
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
4
4
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
1
1
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago
add a comment |
3 Answers
3
active
oldest
votes
up vote
10
down vote
It turns out that for the closest that Mars is to Earth, MRO can transmit at 4.0 Megabits/ second on Ka band. That is enough for standard definition video. So something a bit bigger then MRO could easily transmit video, although only when the two planets are close to each other.
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
add a comment |
up vote
5
down vote
For example, this answer shows the math behind the Voyagers being noise limited with a ~1 kHz bandwidth at 20 billion kilometers. At 100 million km, a Voyager sized antenna with a few Watts would make a signal at earth 46 dB stronger, so you would be noise-limited around (40 MHz) with the 70m dish and receiver with a NEP of 20 Kelvin. These are handwavingly rough numbers, but some kind of reasonable video is possible with existing and not even new technology. But the logistics of making it happen is still a challenge.
The noise-limited bandwidth scales roughly linearly, so if you had 100 W to transmit for 7 minutes, in that case no problem!
answered 11 hours ago
uhoh
32.8k16112401
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
|
show 1 more comment
up vote
3
down vote
Worth mentioning that it takes 3 to 22 minutes for light to reach one of these planets from the other.
And no transmission can exceed light speed, barring a huge overhaul of Physics as we know it.
No equipment ever could have the signal here in less than three minutes.
Any affirmative answers are using a definition of "live" that allows for minutes-long delays.
answered 9 hours ago
Emilio M Bumachar
4451410
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
add a comment |
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
10
down vote
It turns out that for the closest that Mars is to Earth, MRO can transmit at 4.0 Megabits/ second on Ka band. That is enough for standard definition video. So something a bit bigger then MRO could easily transmit video, although only when the two planets are close to each other.
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
add a comment |
up vote
10
down vote
It turns out that for the closest that Mars is to Earth, MRO can transmit at 4.0 Megabits/ second on Ka band. That is enough for standard definition video. So something a bit bigger then MRO could easily transmit video, although only when the two planets are close to each other.
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
add a comment |
up vote
10
down vote
up vote
10
down vote
It turns out that for the closest that Mars is to Earth, MRO can transmit at 4.0 Megabits/ second on Ka band. That is enough for standard definition video. So something a bit bigger then MRO could easily transmit video, although only when the two planets are close to each other.
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
It turns out that for the closest that Mars is to Earth, MRO can transmit at 4.0 Megabits/ second on Ka band. That is enough for standard definition video. So something a bit bigger then MRO could easily transmit video, although only when the two planets are close to each other.
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
answered 10 hours ago
PearsonArtPhoto♦
78.5k16220430
78.5k16220430
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
add a comment |
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
Not sure which antenna they are using, but as NASA uses DSN, and that is either a 35m or 70m antenna, there simply isn't a lot of room for a larger antenna. It could be done, but...
– PearsonArtPhoto♦
9 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
MRO high-gain antenna is 3m in diameter - mars.nasa.gov/mro/mission/spacecraft/parts/antennas
– Jacob Krall
7 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
With enough CPU power for video compression (h.264, h.265, or VP9), good quality 1280x720p30 is very possible at that bitrate. Or depending on how compressible the video is (jerky hand-held imagery with lots of detail in focus tends to be the most difficult), 1080p is also possible. The more CPU time you spend, the better the quality-per-bitrate tradeoff is. This can come at some cost in latency, but that's totally negligible vs. the speed-of-light delay. You could totally break live video up to encode 15-second chunks in parallel, encoding at 1/4 real-time on 4 computers for high quality.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
From a cubesat with a limited power / CPU budget, a fixed-function hardware video encoder like you find in modern video cards and cell phones could do a reasonable job at 4Mbps for 720p content. Presumably the scene would be fairly low motion (and/or consistent motion of everything, so motion vectors for one block predict motion for neighbouring block), so be easy-ish to encode (not take a lot of bitrate for good quality). Depending on the scene, 1Mb/s can be sufficient for youtube quality levels.
– Peter Cordes
2 hours ago
add a comment |
up vote
5
down vote
For example, this answer shows the math behind the Voyagers being noise limited with a ~1 kHz bandwidth at 20 billion kilometers. At 100 million km, a Voyager sized antenna with a few Watts would make a signal at earth 46 dB stronger, so you would be noise-limited around (40 MHz) with the 70m dish and receiver with a NEP of 20 Kelvin. These are handwavingly rough numbers, but some kind of reasonable video is possible with existing and not even new technology. But the logistics of making it happen is still a challenge.
The noise-limited bandwidth scales roughly linearly, so if you had 100 W to transmit for 7 minutes, in that case no problem!
answered 11 hours ago
uhoh
32.8k16112401
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
|
show 1 more comment
up vote
5
down vote
For example, this answer shows the math behind the Voyagers being noise limited with a ~1 kHz bandwidth at 20 billion kilometers. At 100 million km, a Voyager sized antenna with a few Watts would make a signal at earth 46 dB stronger, so you would be noise-limited around (40 MHz) with the 70m dish and receiver with a NEP of 20 Kelvin. These are handwavingly rough numbers, but some kind of reasonable video is possible with existing and not even new technology. But the logistics of making it happen is still a challenge.
The noise-limited bandwidth scales roughly linearly, so if you had 100 W to transmit for 7 minutes, in that case no problem!
answered 11 hours ago
uhoh
32.8k16112401
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
|
show 1 more comment
up vote
5
down vote
up vote
5
down vote
For example, this answer shows the math behind the Voyagers being noise limited with a ~1 kHz bandwidth at 20 billion kilometers. At 100 million km, a Voyager sized antenna with a few Watts would make a signal at earth 46 dB stronger, so you would be noise-limited around (40 MHz) with the 70m dish and receiver with a NEP of 20 Kelvin. These are handwavingly rough numbers, but some kind of reasonable video is possible with existing and not even new technology. But the logistics of making it happen is still a challenge.
The noise-limited bandwidth scales roughly linearly, so if you had 100 W to transmit for 7 minutes, in that case no problem!
answered 11 hours ago
uhoh
32.8k16112401
For example, this answer shows the math behind the Voyagers being noise limited with a ~1 kHz bandwidth at 20 billion kilometers. At 100 million km, a Voyager sized antenna with a few Watts would make a signal at earth 46 dB stronger, so you would be noise-limited around (40 MHz) with the 70m dish and receiver with a NEP of 20 Kelvin. These are handwavingly rough numbers, but some kind of reasonable video is possible with existing and not even new technology. But the logistics of making it happen is still a challenge.
The noise-limited bandwidth scales roughly linearly, so if you had 100 W to transmit for 7 minutes, in that case no problem!
answered 11 hours ago
uhoh
32.8k16112401
edited 10 hours ago
answered 11 hours ago
uhoh
32.8k16112401
answered 11 hours ago
uhoh
32.8k16112401
answered 11 hours ago
uhoh
32.8k16112401
32.8k16112401
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
|
show 1 more comment
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
Could laser based communication help in securing a wider bandwidth?
– karthikeyan
11 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan I'm not sure if the "existing technology" requirement applies there. X-band microwaves get to the Earth just fine, day or night, clear or cloudy. Optical needs good night-time weather or a receiver in orbit. These things need to be built, but in principle it could work. How is long-distance optical communications coming along in space? and also Are there plans or a program for an optical relay pathfinder for deep space?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
@karthikeyan Something more recent, but not for deep space yet: Yet another OSIRIS! Has the DLR/GOM Space test of the cubesat optical communications link happened yet?
– uhoh
10 hours ago
1
1
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
@karthikeyan My answer is based on X-band and that's that. If you like, you are welcome to add an additional optical answer. Don't forget to include a discussion of how it uses existing technology, not just existing knowledge.
– uhoh
10 hours ago
1
1
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
I'll consider adding some, if I could find authoritative references
– karthikeyan
10 hours ago
|
show 1 more comment
up vote
3
down vote
Worth mentioning that it takes 3 to 22 minutes for light to reach one of these planets from the other.
And no transmission can exceed light speed, barring a huge overhaul of Physics as we know it.
No equipment ever could have the signal here in less than three minutes.
Any affirmative answers are using a definition of "live" that allows for minutes-long delays.
answered 9 hours ago
Emilio M Bumachar
4451410
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
add a comment |
up vote
3
down vote
Worth mentioning that it takes 3 to 22 minutes for light to reach one of these planets from the other.
And no transmission can exceed light speed, barring a huge overhaul of Physics as we know it.
No equipment ever could have the signal here in less than three minutes.
Any affirmative answers are using a definition of "live" that allows for minutes-long delays.
answered 9 hours ago
Emilio M Bumachar
4451410
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
add a comment |
up vote
3
down vote
up vote
3
down vote
Worth mentioning that it takes 3 to 22 minutes for light to reach one of these planets from the other.
And no transmission can exceed light speed, barring a huge overhaul of Physics as we know it.
No equipment ever could have the signal here in less than three minutes.
Any affirmative answers are using a definition of "live" that allows for minutes-long delays.
answered 9 hours ago
Emilio M Bumachar
4451410
Worth mentioning that it takes 3 to 22 minutes for light to reach one of these planets from the other.
And no transmission can exceed light speed, barring a huge overhaul of Physics as we know it.
No equipment ever could have the signal here in less than three minutes.
Any affirmative answers are using a definition of "live" that allows for minutes-long delays.
answered 9 hours ago
Emilio M Bumachar
4451410
answered 9 hours ago
Emilio M Bumachar
4451410
answered 9 hours ago
Emilio M Bumachar
4451410
answered 9 hours ago
Emilio M Bumachar
4451410
4451410
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
add a comment |
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
4
4
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
This is true, I didn't mean to include speed of light delay to preventing live. I meant video that is sent in real time from the spacecraft, of course it can't be received in real time.
– PearsonArtPhoto♦
9 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
Or a coordinate system in which light travels from Mars to Earth instantaneously.
– Acccumulation
6 hours ago
3
3
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
Using this answer, to be pedantic, there's no such thing as "live" anything, as it takes a finite amount of time for a photon to travel so much as one plank length.
– Phil
5 hours ago
add a comment |
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2
It depends on what the meaning of "exists" is. By exists, do you mean you'll allow for a few years to put it into a new satellite and put it in orbit around Mars or on the surface, or that it would have to use the satellites and landers already present at Mars?
– uhoh
11 hours ago
4
What do you mean? Are you asking about bandwidth? Speed of light? Power? Nyquist–Shannon? Compression? -1 for asking an extremely unclear question then answering it yourself with the answer you were looking for without give others clear direction as to what you were looking for.
– Sam
9 hours ago
Mostly the bandwidth.
– PearsonArtPhoto♦
9 hours ago
1
The two cubesats allow for live telemetry relay, not video. Useful, especially if something were to go wrong during descent. (Without the cubesats, InSight would've had to save its telemetry and upload after a successful landing.)
– ceejayoz
6 hours ago
Agree with @Sam. I can't even guess what information you might possibly be looking for just from reading. Youd don't clarify what limitations you have in mind, you don't clarify what you expect to happen, you don't clarify what research you've done on the issue. There's just nothing in the question that gives anyone context to answer. Would happily downvote if I could and have flagged for closure as Unclear.
– jpmc26
2 hours ago