NASA Pushes Laser-Based Broadband Forward Moving From 6Mbps to 100 Mbps Thursday Sep 01 2011 12:28 EDT Back in 2004 I remember reading a New Scientist article that explored how NASA was developing Laser technology that would let Earth communicate with spacecraft at 30 million bits per second -- compared to the top speed of 128,000 bits per second at the time. Many years later and NASA is announcing that they're finally pushing their laser-based broadband plans forward, with a new deployment of the technology they say should result in increased speeds from the now-6Mbps they see currently -- to 100 Mbps. From the NASA press release: quote:
Data rates 10-100 times more capable than current RF systems will allow greatly improved connectivity and enable a new generation of remote scientific investigations as well as provide the satellite communication’s industry with disruptive technology not available today. Space laser communications will enable missions to use bandwidth-hungry instruments, such as hyperspectral imagers, synthetic aperture radar (SAR), and other instruments with high definition in spectral, spatial, or temporal modes. Laser communication will also make it possible to establish a “virtual presence” at a remote planet or other solar system body, enabling the high-rate communications required by future explorers.
As an example, NASA notes that at current speeds the Mars Reconnaissance Orbiter (MRO), needs around 90 minutes to transmit a single HiRISE high resolution image back to earth. With a laser-based connection, NASA says that same transmission would take roughly five minutes. |
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Interesting....Very impressive speeds. This technology would also do wonders for future space missions and it may even have some applications here on Earth as well. | |
| mikefxu
join:2004-10-05
Titusville, FL |
LatencyYou can fatten the pipe but you can't beat the speed of light (latency). | |
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Re: LatencySure, Latency is always going to be a problem with satellite and long distance communications, but this technology could still greatly help speeds. For example, I have hughesnet internet. On a satellite like what you'd find with them, you have many people all connecting to the same place (in this case, northeast US). If they were to implement this technology on the connection between the NOC (network operations center) and the satellite, the bottleneck on that leg of the journey would I think be greatly reduced, which means either better speeds for the end-user or the ability to pack more users on the same satellite. This plan also wouldn't require them to change the modems of consumers, though they would have to launch new satellites, which means it might not happen anytime soon.  | |
| | | mikefxu
join:2004-10-05
Titusville, FL
1 recommendation |
Re: LatencyWe have used satellite for 7+ years, both WildBlue and HughesNet/DirectWay at our remote job sites and have watched as latency has gotten worse as they pack more subscribers on. There would be a honeymoon period then they would eventually pack it full. | |
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 rchandraStargate Universe fan
Premium Member
join:2000-11-09
14225-2105
EnGenius EAP1250
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rchandra
Premium Member
2011-Sep-1 1:05 pm
line of sight, right?I mean, they did mention lasers, right? Seems to me trying to keep a laser pointed at Mars might be quite challenging. And...you think rain fade is bad for today's TV satellite dishes...last I checked, light is either dispersed or absorbed fairly well by any overhead clouds. How are enough photons going to get through on a cloudy day? hmmmmmm.....dunno about this... | |
| |  coldmoon
Premium Member
join:2002-02-04
Fulton, NY |
coldmoon
Premium Member
2011-Sep-1 1:29 pm
Re: line of sight, right?said by rchandra:I mean, they did mention lasers, right? Seems to me trying to keep a laser pointed at Mars might be quite challenging. And...you think rain fade is bad for today's TV satellite dishes...last I checked, light is either dispersed or absorbed fairly well by any overhead clouds. How are enough photons going to get through on a cloudy day? hmmmmmm.....dunno about this...
Well if you set it up with the laser originating from an orbital satellite and then place relays out at different locations around the solar system, wouldn't that take care of the line of sight issue? It would take some serious investment in infrastructure, but it would also be a good way to beat the atmospheric issues here on the ground; at least eliminate the absorption and scattering issues if you use RF out to the orbiting laser base stations... | |
| |  jmn1207
Premium Member
join:2000-07-19
Sterling, VA |
to rchandra
said by rchandra:I mean, they did mention lasers, right? Seems to me trying to keep a laser pointed at Mars might be quite challenging. And...you think rain fade is bad for today's TV satellite dishes...last I checked, light is either dispersed or absorbed fairly well by any overhead clouds. How are enough photons going to get through on a cloudy day? hmmmmmm.....dunno about this...
They would probably use stationary laser signal transmitters/receivers that were located in orbits that were synchronized and positioned to be facing each other and in a near constant pairing between Earth and Mars. These stationary devices would be pointed at each other, using lasers to send the signals back and forth. Then a more typical radio signal could be used from each planet to the stationary laser transmitter/receiver. | |
| | | rradina
join:2000-08-08
Chesterfield, MO |
Re: line of sight, right?That's also my guess. I don't think it's feasible to use this as an up/down link from Earth stations to satellites. This would only work in outer space. Even devoid of clouds, temperature variations in our atmosphere wreak havoc with light waves.
I'm thinking RF links between Earth and satellites aren't the bottleneck. A long time ago when I had Dish/DirecTV services, I think I read that a single DBS (small dish) transponder frequency was capable of 35Mbit/second and satellites have multiple transponder frequencies (like 20 or 30 or more).
I would guess an up/down link with a BIG dish could transmit many gigabits per second regardless of rain/snow/hail. | |
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| | | |  Matt3All noise, no signal.
Premium Member
join:2003-07-20
Jamestown, NC |
Matt3
Premium Member
2011-Sep-1 2:57 pm
Re: line of sight, right?said by myokitis:Two words: Rain. Clouds.
There are none in space. The ground to satellite link can utilize RF and/or optical. | |
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Re: line of sight, right?said by Matt3:said by myokitis:Two words: Rain. Clouds.
There are none in space. True, none in space, but if a dark cloud or rain could passes between either earth statation and satellite, wouldn't it block or disperse the laser light? In the diagram attached to the article, if a dark cloud somes between the ground station in Hawaii and the Space Terminal, I can't see how communications could remain intact. I expect that weather-based reliability would depend on the climate . . . If you're in a desert you'd be OK, but otherwise you would have weather-related issues. | |
| | | | | Matt3All noise, no signal.
Premium Member
join:2003-07-20
Jamestown, NC |
Matt3
Premium Member
2011-Sep-1 5:05 pm
Re: line of sight, right?said by myokitis:said by Matt3:said by myokitis:Two words: Rain. Clouds.
There are none in space. True, none in space, but if a dark cloud or rain could passes between either earth statation and satellite, wouldn't it block or disperse the laser light? In the diagram attached to the article, if a dark cloud somes between the ground station in Hawaii and the Space Terminal, I can't see how communications could remain intact. I expect that weather-based reliability would depend on the climate . . . If you're in a desert you'd be OK, but otherwise you would have weather-related issues. As I noted, that is why the ground to satellite link can also use RF in addition to optical. You can easily shove 100Mbps via RF to a satellite. Most current generation satellite uplinks are in the Gbps range. If a single ground station is only using optical, then you are absolutely correct, a visual obstruction may be a problem, but there are wavelengths they can use that wouldn't be absorbed by the cloud or rather, what typically compromises the cloud. | |
| | | | | |  firefox
Premium Member
join:2000-12-03
Sunnyvale, CA |
firefox
Premium Member
2011-Sep-2 2:20 am
Re: line of sight, right?The dollar cost for setting up 1Gbps (or greater) satellite bandwidth as well as the maintenance and power requirements would be out of this world.  | |
| | | | | | | Matt3All noise, no signal.
Premium Member
join:2003-07-20
Jamestown, NC |
Matt3
Premium Member
2011-Sep-2 10:42 am
Re: line of sight, right?said by firefox:The dollar cost for setting up 1Gbps (or greater) satellite bandwidth as well as the maintenance and power requirements would be out of this world.
Hey, if you shoot for the moon and miss, you still wind up among the stars. | |
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|  jslikThat just happened
Premium Member
join:2006-03-17 |
to rchandra
From the 2004 article: quote:
The new Mars laser project will use two different sites to detect the laser on Earth - the 5-metre Hale Telescope in southern California and an array of four 0.8-metre telescopes whose location has yet to be determined. If the weather is overcast at one location, astronomers can try the next. Future projects are likely to have a dozen telescopes spaced around the world.
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 MalibuMaxx
Premium Member
join:2007-02-06
Chesterton, IN |
hmn...I'm not saying its impossible just very difficult... heck we have a hard enough time getting 100 meg to our homes...
I'd have to say its line of sight... and if thats the case... it think it will be a joke to say the least... | |
| |  NOCTech75
Premium Member
join:2009-06-29
Marietta, GA |
Re: hmn...said by MalibuMaxx:I'm not saying its impossible just very difficult... heck we have a hard enough time getting 100 meg to our homes...
I'd have to say its line of sight... and if thats the case... it think it will be a joke to say the least...
Joke for who? The only thing that is funny is slamming the agency for a pretty impressive feat that could have later uses down the road for the civilian world. | |
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jfmezei
Premium Member
join:2007-01-03
Pointe-Claire, QC |
jfmezei
Premium Member
2011-Sep-1 1:19 pm
Orbiting bodies are a challengePrecise tracking of an orbiting satellite/space station is hard since the object is constantly moving relative to a fixed position on earth.
I know they did some tests with the space shuttle, a ground based laser aimed at a shuttle window. And it seemed to work. However, they'll need to develop sensors that are large enough to realistically capture a laser beam. You can't hope to aim a laser from the ground to a moving object if the target is a pinhole sized sensor. | |
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cruz1
Anon
2011-Sep-1 1:26 pm
I would think radio is better ...I would think radio is better at penetrating small obstacles. With a tiny laser, all you need is a bird (on earth) or tiny rocks (space) to block the transmission. They could always use a bigger chunk of bandwidth ...
But ... One possibility is having a satellite in space using the laser to communicate with Mars rover, etc, then beam to earth via high speed shorter distance microwaves to eliminate line of sight issues.. Either way, they need to have at least one RF backup... | |
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Fire the laserFire the laser.
Target destroyed, sir.
I meant the communications laser! | |
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Re: Fire the laserThey could have RF and laser for a residential subscriber where it would convert over to RF in case of rain/clouds. The service could at least be utilized in areas that do not get much rain/clouds. | |
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|  Rogue WolfAn Easy Draw of a Sad Few
join:2003-08-12
Troy, NY |
to cruz1
Re: I would think radio is better ...That would probably be the best way to go about it: Laser communication between orbiting stations, and then RF/microwave relay to any planetside recipients.
The difference between the speeds of light and sound is fairly insignificant when it comes to satellites, but when you're dealing with (literally) interplanetary distances, it seriously adds up. | |
| | | rradina
join:2000-08-08
Chesterfield, MO |
Re: I would think radio is better ...What's that you say? The difference between the speed of light and sound doesn't make a difference when it comes to satellites...
Geosync satellites are in orbit at ~25,000 miles from Earth's equator. Light travels at 186,000 miles per second. This means a PING to a satellite (up and back) takes 286ms. By comparison, the speed of sound is a paltry ~750mph or about 1 mile every five seconds. At this rate, it would take almost 70 hours to PING to a geosync satellite.
At their closest distance, Earth and Mars are about 56 million miles apart. If we used the speed of sound to get there, it would take over 8 years, one way.
In my opinion, the difference between the speed of sound and the speed of light makes a difference over almost ANY distance. | |
| | | | Rogue WolfAn Easy Draw of a Sad Few
join:2003-08-12
Troy, NY |
Re: I would think radio is better ...I don't think you read my post correctly. I said using lasers over long distances and then radio or MW waves from orbit to planetside. As for using laser planetside, then you have to worry about atmospheric scattering, obstructions, any sort of inaccuracy in targeting, etc. At what point do you trade speed for dependability? | |
| | | | | rradina
join:2000-08-08
Chesterfield, MO |
Re: I would think radio is better ...Agreed about using RF for Earth to satellite link but what does the word "sound" mean in your post? Are you equating sound with RF/electromagnetic transmission methods? Light and RF travel at the same super fast speed. I'm really confused. | |
| | | | | | Rogue WolfAn Easy Draw of a Sad Few
join:2003-08-12
Troy, NY |
Re: I would think radio is better ...Well, I feel silly about this one because I thought that radio frequencies moved slower in atmosphere than outside of it.  So disregard that brain fart of mine. But I still hold to the previous idea that laser isn't the best idea in atomspheric conditions. | |
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100 megabits.. AWESOME!But I bet latency is a bitch... LOL. | |
|  a333A hot cup of integrals please
join:2007-06-12
Rego Park, NY |
a333
Member
2011-Sep-2 11:09 am
awesome techThis is actually fairly awesome tech.... I've lost track of the number of deep-space missions where lack of bandwidth is simply frustrating... we're talking about RF links on the order of BITS per second here...
A laser-based system might be the solution in those cases, where obstructions are expected once in a while, but not nearly as common as those encountered in low-earth comms. Also, NASA probably plans on combining this tech with the research they have already been doing on DTN (Disruption-tolerant networking, basically a space-based alternative to our terrestrial TCP/IP protocols that tend to expect somewhat reliable links impossible when communicating between planets). I must say though, the attitude control system required to keep a laser pointed at some point on Earth from millions of miles away will have to have extreme accuracy (probably implemented through a combo of a very highly accurate gyro and some kind of sun-sensor).
--a333 | |
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