Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

NASA Creating Laser Communication System For Mars

samzenpus posted more than 3 years ago | from the mars-needs-lasers dept.

NASA 104

techtribune writes "NASA is in the process of developing a new technology under project Laser Communications Relay Demonstration or LCRD which will allow them to provide faster means of communications from Mars. The Mars Reconnaissance Orbiter (MRO) currently can only send at speeds of around 6 Mbps or about like a DSL modem here on Earth. At this rate, it can take upwards to 90 minutes to transmit a single high resolution image to Earth from Mars. With the MRO outfitted with the new technology it would be able to transmit the same high resolution image back to Earth at over 100 Mbps and only taking about 5 minutes to do so."

Sorry! There are no comments related to the filter you selected.

Just don't mis-aim! (1)

TWX (665546) | more than 3 years ago | (#37197556)

Just don't mis-aim the laser. I'd hate for my city to blow up like in Sim City 2000 when the orbiting solar plant's beam goes off-kilter...

Re:Just don't mis-aim! (1)

Anonymous Coward | more than 3 years ago | (#37197770)

Those mis-aimed beams in Sim City 2000 were microwave, actually. Which is what we use today for such interplanetary communications. So I daresay this will only make us safer!

Re:Just don't mis-aim! (1)

PPH (736903) | more than 3 years ago | (#37197980)

Think of the poor amateur astronomers looking at Mars through their backyard telescopes.

Re:Just don't mis-aim! (1)

Chris Burke (6130) | more than 2 years ago | (#37206700)

Hey, you need a solar filter to look at the sun, now you'll just have to buy a Mars-laser filter to safely look at Mars! It's a business opportunity!

But (1)

symes (835608) | more than 3 years ago | (#37197562)

What if it's cloudy?

Re:But (3, Funny)

decipher_saint (72686) | more than 3 years ago | (#37197634)

Well then I would suspect that the orbit is dangerously low and the last message would likely read: "Ack!"

Re:But (0)

Anonymous Coward | more than 3 years ago | (#37198170)

No, "NAK"

Re:But (0)

Anonymous Coward | more than 3 years ago | (#37198228)

No, the last message would be: "SYN"

but why? (2)

Lead Butthead (321013) | more than 3 years ago | (#37198092)

why would they want a probe orbiting Mars to communicate with sharks?

6 mbps on Mars? (2)

americamatrix (658742) | more than 3 years ago | (#37197598)

That's still faster than most connections in the US! That's not bad at all!

Re:6 mbps on Mars? (1)

Spy Handler (822350) | more than 3 years ago | (#37197682)

yeah but there's a big latency so WOW is gonna lag like hell...

Re:6 mbps on Mars? (1)

shugah (881805) | more than 3 years ago | (#37197752)

That's where the sharks come in.

Re:6 mbps on Mars? (0)

Anonymous Coward | more than 2 years ago | (#37201228)

You just have to play on the local servers.

Re:6 mbps on Mars? (2)

Wesley Felter (138342) | more than 3 years ago | (#37197720)

Yeah, but the whole planet has to share 6 Mbps.

Re:6 mbps on Mars? (0)

Anonymous Coward | more than 3 years ago | (#37199150)

still pretty good per person.

Re:6 mbps on Mars? (1)

Sinthet (2081954) | more than 2 years ago | (#37200396)

Technically it's undefined.

90 minutes: partially due to speed of light limit (1)

rwade (131726) | more than 3 years ago | (#37197756)

From the summary:

At this rate, it can take upwards to 90 minutes to transmit a single high resolution image to Earth from Mars

At least part of this 90 minute transmission time is due to the maximum speed of light, not the date rate. According to NASA, it takes 10 to 20 minutes [nasa.gov] to get a signal from Mars to Earth:

How long does it take for a signal to be sent from Earth to Mars?

Signals to/from Mars travel at the speed of light (186,000 miles per second, or 300,000 kilometers per second). It takes between 10 and 20 minutes for a signal to travel from Earth to Mars, depending on the relative position of the planets at that time.

Re:90 minutes: partially due to speed of light lim (1)

Anonymous Coward | more than 3 years ago | (#37197766)

Math is hard, please help me.
6Mbps ~ 600KBs
600KB/s * 60 seconds/min * 90 minutes == ~3.2GB

So if the image is a raw 32 bit TIFF we're looking at at image of 28k x 28k pixels. Me thinks someone should introduce them to JPG compression.

Possible that JPEG compression too much to handle (1)

rwade (131726) | more than 3 years ago | (#37197880)

I'm just speculating, but a risk-averse JPL may be concerned about using a JPEG because the extra work of compressing the raw image to a JPEG would be one more failure item on already very-complicated space probes.

Like I said, that's just my theory -- a quick google of "space probe image compression" didn't turn up anything for me; maybe others would have luck.

Discrediting my theory is a note on the Galileo Wikipedia entry [wikipedia.org] regarding the use of data compression to improve throughput after the high-gain antenna was discovered as damaged:

Through implementation of sophisticated data compression techniques, arraying of several Deep Space Network antennas and sensitivity upgrades of receivers used to listen to Galileo's signal, data throughput was increased to a maximum of 160 bits per second.

Re:90 minutes: partially due to speed of light lim (5, Informative)

AndrewBuck (1120597) | more than 3 years ago | (#37197904)

Science images are NEVER EVER compressed in JPEG. In fact they probably don't even use the TIFF format either. Almost all science images in astronomy are done in the FITS [wikipedia.org] format which I think was developed by NASA. This is because not only does the image need to be lossless raw data in order to be used for proper scientific measurements, but also much metadata must be included with the frame for some kinds of science observations.

Common metadata will include the position of the camera (where the orbiter was when the picture was taken), the camera's orientation (which way it was looking at the time), the exact time when the image was taken, the image exposure time, the camera's CCD temperature, whether on-chip binning has been carried out, the camera's readout noise, the camera's gain, etc. All of this information is necessary for some kinds of science and therefore NASA doesn't want to lose any of this information.

-Buck

Re:90 minutes: partially due to speed of light lim (4, Informative)

serviscope_minor (664417) | more than 3 years ago | (#37198336)

. This is because not only does the image need to be lossless raw data in order to be used for proper scientific measurements, but also much metadata must be included with the frame for some kinds of science observations.

Pedantically speaking, TIFF also allows for arbitrary metadata. And all sorts of other bizarre crap. FITS is a much older format and part of the reason it is used is historical.

The main reason it is used is that it is a format specifically designed for archival use. It is a very simple format and one can easily write an image parser and writer from scratch which will happily accept and be accepted by most systems (so that ignores the more obscure non image options). I have done so.

NASA quite rightly expect FITS images to be readable in 100 years time. This is reasonable since you could probably write that parser in a couple of days without even having access to the spec. TIFF by comparison is not a simple file format.
t's also not a bad format. Lossless compression will get you at most 3x on a natural image with 8 bits per channel, but more like 1.5-2, and often is not worth the bother, especially as support for TIFF compression is somewhat spotty once it moves into more than 8 bits per channel.

one marginally irritating thing about FITS is that it is in column-major format (yay @ fortran) rather than row major, where as most capture hardware and other image formats are row-major. So, loaading/saving FITS images often requires a quadrupal for-loop (endian/channels/rows/cols) to rearrange the data.

But back on topic: 6mpbs over 400e6 km is amazing!

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 2 years ago | (#37200066)

Since a lot of the meta-data like photon lists, data-cubes, etc. stored inside of FITS images are usually not part of the original format specification and requires the original code in whatever language the creator chose to create it in I really doubt most of it will be readable in 100 years. The image, maybe.

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 3 years ago | (#37198452)

Well, that is not entirely true. Once thing is onboard data compression, and another data archival. There are lossy image coding standards specially targeted at spacecrafts (e.g. CCSDS 121 http://public.ccsds.org/sites/cwe/rids/Lists/1220R2/NASAUSOverview.aspx). While there is certainly a lossless data compression need, given the usual bandwidth constraints, having a larger, even if not perfect, image is a valid use case. In this last case, having a coding loss below the instrument tolerance often helps convince scientist.

Re:90 minutes: partially due to speed of light lim (1)

Nethemas the Great (909900) | more than 3 years ago | (#37199276)

There are plenty of lossless image compression techniques. There are even standardized file formats that could be used. For instance JPEG2000 can use CDF 5/3 wavelet compression (lossless) and supports user defined XML metadata boxes. In other words 100% reversible image compression plus whatever metadata payload they wanted to include.

Re:90 minutes: partially due to speed of light lim (1)

Gib7 (2445652) | more than 2 years ago | (#37200304)

Math looks good (although upper case "K" is Kelvin - you need lower case "k" for kilo...), but I suspect there's a large dose of redundancy and Error-correction information included in that 6Mbps. It's not like you can have an efficient retry protocol with a 20 minute ping time. So, there'd be less than 3.2GB of useful data sent. Probably between 50% and 70% would be actual image.

Re:90 minutes: partially due to speed of light lim (1)

nospam007 (722110) | more than 2 years ago | (#37203844)

Yeah, let's decide a compression algorithm what's an important detail on extraterrestrial pictures.

Re:90 minutes: partially due to speed of light lim (1)

AndrewBuck (1120597) | more than 3 years ago | (#37197806)

Wrong. The 10 to 20 minutes you speak of is the latency, however this 90 minute figure is probably arrived at by taking the size of the image and dividing by the 6mbps transfer rate. It will take 10-20 minutes after the first bits leave Mars and arrive at Earth, however after Earth sees the first bit they will still have to wait 90 minutes to see the last bit.

-Buck

Don't you mean "probably wrong"? (1)

rwade (131726) | more than 3 years ago | (#37197972)

Wrong.

Hmm...okay, why?

however this 90 minute figure is probably arrived at by taking the size of the image and dividing by the 6mbps transfer rate.

So let me correct that for you:

Probably Wrong.

Re:90 minutes: partially due to speed of light lim (1)

geekoid (135745) | more than 3 years ago | (#37198352)

Delay, not latency.

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 3 years ago | (#37199298)

"Latency is a measure of time delay experienced in a system, the precise definition of which depends on the system and the time being measured."

From wikipedia.

Re:90 minutes: partially due to speed of light lim (1)

Co0Ps (1539395) | more than 3 years ago | (#37197960)

No TFS is right. You're talking about latency. The summary talks about bandwidth. Latency and bandwidth are two completely different things. The time it talks for the recipient to download the image from transfer start to end is 90 minutes, no matter if you send the image from mars, jupiter or alpha centauri. Unless you use TCP.

Re:90 minutes: partially due to speed of light lim (1)

gstrickler (920733) | more than 3 years ago | (#37198424)

6Mbps * 60 sec = 360 Mb/m = 45 MiB/min * 60min = 2.7GiB/hr. Are they saying they're transmitting images that exceed 2.7GiB per image? Assuming 8 bits per "color" and a 6 channel "color", that's a 450M-pixel image. Even at 12b/channel, it's a 300M-pixel image, or 20K x 15K (4:3 aspect ratio) resolution image. Call me skeptical, but I think there has been a mistake.

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 3 years ago | (#37198660)

Are they saying they're transmitting images that exceed 2.7GiB per image?

Yep. When I did remote sensing work we had to update the TIFF library to support the BigTIFF format (> 4GB). It's not that uncommon. 32 bits per channel is also not uncommon. Sometimes even a double per channel. Hyperspectral images also have way more than 6 channels.

Re:90 minutes: partially due to speed of light lim (2)

gstrickler (920733) | more than 3 years ago | (#37199448)

Your point is valid, except that the HIRISE imager on the MRO [wikipedia.org] only produces images of 16.4Gb (2.05 GB) before compression, 5Gb (630MB) after compression in red, and 1/5 of that for blue/green channels. It's only a 3 channel device. The CTX camera is lower resolution with only a single channel. MARCI operates in 7 channels, but it's also low resolution.

The MCS spectrometer operates in 9 channels, but is very low resolution.

That leaves the CRISM spectrometer as the only imager on MRO with a large number of channels. It can image 50 or 544 channels depending upon the mode. But again, it's comparatively low resolution (~ 1/40 that of HIRISE, which means about 1/1600th as many pixels in a given area), which more than offsets the increase in number of channels.

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 2 years ago | (#37202826)

There is an error in your calculation. It should be:

6Mbps = 6 000 000 bps = 750 000 B/s = 732.42 KiB/s

So, it is more like this:
732.42 KiB/s * 60 seconds = 42.91 MiB/s
42.91 MiB/min * 60 minutes = 2.51 GiB/hour

But, that is not taking any latency into account. A ping of 40 minutes round time is HORRIBLE, and if their protocol is anything like TCP, it would take 40 minutes to transmit a single round trip "packet" which is only about 1500 bytes big. I do realize that they're using something else which is a lot more asynchronous, but the lag is still gonna slow it down a lot regardless.

PS: Only realized halfway through my pedantic calculation that you have converted into bytes from bits...

Re:90 minutes: partially due to speed of light lim (1)

roc97007 (608802) | more than 3 years ago | (#37199690)

Um, Unless you were kidding, the transit time is a measure of LAG, not transfer speed. The original statement, that it can take 90 minutes to transmit an image to Earth, is a measure of the transfer speed, IE, when the message finishes leaving the orbiter. When Earth actually receives it is a different question. So the 10 to 20 minute speed of light lag would be in addition to the the 90 minute estimate.

Re:90 minutes: partially due to speed of light lim (1)

f()rK()_Bomb (612162) | more than 2 years ago | (#37200310)

they clearly aren't including the limit considering the new one takes 5 mins instead of 90.

Re:90 minutes: partially due to speed of light lim (0)

Anonymous Coward | more than 2 years ago | (#37200682)

Speed of light has nothing to do with it. It's not transmitted with an Ack/Nak protocol from Mars. It's just the few Mbps in a solid stream of transfer frames.

From Wikipedia for HiRise (the MRO camera) A single uncompressed image uses up to 28 Gb. However, these images are transmitted compressed,with a typical max size of 11.2 Gigabits. These images are released to the general public on the HiRISE website via a new format called JPEG 2000.

I note that JPEG2000 can be run in a lossless form, just like TIFF.

At 2 Mbps, that's about 90 minutes.

They probably can't do 6Mbps when Mars is farthest from Earth, but when it's only 0.5 AU away at closest approach, that's reasonable.

Not speed, latency. (1)

Guspaz (556486) | more than 3 years ago | (#37197772)

The speed isn't the issue. A sufficiently well focused and powerful laser (or multiple lasers) could probably push as much bandwidth as you need. The problem is the latency.

The distance between Earth and Mars varies from between roughly 56 and 399 million kilometres. That's a minimum round-trip time of ~374,000ms and a maximum round trip time of ~2,600,000ms, ignoring the speed of light in atmosphere. Somebody's going to make a killing selling Squid boxes when we get around to colonizing the place.

Re:Not speed, latency. (2)

JoshuaZ (1134087) | more than 3 years ago | (#37197804)

No. The issue here is not the latency. Latency is a problem (it is a major issue with the rovers. Trying to direct them where to go and then waiting to see if they run into problems is a big nuisance). But here the total problem is bandwith. The total bandwith is low, so it takes a very long time to send data from Mars to Earth. We get far more data on Mars than we can even send back to the Earth. Even with this new system that will still be the case but if it works it won't be nearly as bad. This will improve the total bandwith a lot.

Re:Not speed, latency. (1)

jtownatpunk.net (245670) | more than 3 years ago | (#37197840)

Actually, I think the bandwidth is pretty darn high. 6mbps is pretty impressive given the distance. I had no idea they could pump data that fast between planets.

Re:Not speed, latency. (0)

Anonymous Coward | more than 3 years ago | (#37197944)

Yeh that actually is impressive bandwidth. I can understand why they would want to improve upon that though, so that they can transmit more photos/data and get their moneys worth out of that rover that probably cost a boat load to get to mars.

Re:Not speed, latency. (1)

JoshuaZ (1134087) | more than 3 years ago | (#37198068)

Well yes, it is high for most purposes. It is very low compared to how much data is being produced.

Re:Not speed, latency. (0)

Anonymous Coward | more than 2 years ago | (#37206480)

Spot on.

MRO has a big ol' 3-meter dish. It blows every other deep-space orbiter ever made out of the water -- almost 140Tb of downlink volume to date, more than all of them combined. But it, and every other mission, can take wayyyyy more data than it can transmit back.

Like you said, it's not a latency issue. Light time is what it is, and we deal with it in very well-defined ways. It's about bandwidth, not latency.

Re:Not speed, latency. (1)

Guspaz (556486) | more than 2 years ago | (#37205560)

I meant that while the new system makes a big improvement in bandwidth, it can't do anything about the latency due to the speed of light.

Re:Not speed, latency. (1)

Nyeerrmm (940927) | more than 3 years ago | (#37199342)

Bandwidth is an issue. Telemetry is extremely tightly budgeted on a mission like this, and being able to get more back would vastly increase the available science data as well as simplify operations.

And a high-powered laser is not a trivial task. First, all the power comes from solar cells, which are themselves heavy and they try to keep them minimized. Second, when you're pumping a lot of energy through a laser, you end up with a lot of heat that is difficult to discard. You can't bleed it off through convection or conduction, so you have to rely on radiators for everything and those get big and heavy too. This tech development project is incredibly important for trying to work out these kinds of issues.

Now, if you can find a way around the latency issues I'm all ears.

Re:Not speed, latency. (0)

Anonymous Coward | more than 2 years ago | (#37201916)

How about beam down via radio to the martian surface then back to Earth via lasers? Should be easier to land lots of solar panels.

Re:Not speed, latency. (1)

Anonymous Coward | more than 3 years ago | (#37199658)

Somebody's going to make a killing selling Squid boxes when we get around to colonizing the place.

Not Squid on Linux - net/ipv4/tcp_timer.c

/* Increase the timeout each time we retransmit. Note that
* we do not increase the rtt estimate. rto is initialized
* from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
* that doubling rto each time is the least we can get away with.
* In KA9Q, Karn uses this for the first few times, and then
* goes to quadratic. netBSD doubles, but only goes up to *64,
* and clamps at 1 to 64 sec afterwards. Note that 120 sec is
* defined in the protocol as the maximum possible RTT. I guess
* we'll have to use something other than TCP to talk to the
* University of Mars.
*
* PAWS allows us longer timeouts and large windows, so once
* implemented ftp to mars will work nicely. We will have to fix
* the 120 second clamps though!
*/

Re:Not speed, latency. (1)

vadim_t (324782) | more than 2 years ago | (#37202084)

FTP would be a bad protocol for file transfer to Mars with so much talk back and forth.

I figure they'd use HTTP POST or something similar.

Perpetual Funding (1)

retroworks (652802) | more than 3 years ago | (#37197786)

If Comcast or a cell phone company manages it, they could pay for the space station from the profits on bandwith!

What about dropped packets? (1)

AvderTheTerrible (1960234) | more than 3 years ago | (#37197802)

At those speeds, I cant imagine that there isnt some lost/corrupted data. Does retransmission factor into the 90 minute time, or are they using so many redundant signals that theres no need for a TCP-like packed received ack? Whenever communication between Earth and Mars comes up I just have to wonder how long it's going to be until we find a way to communicate faster than light using something like quantum nonlocality. Otherwise were going to need two internets once we finally colonize that rusted out wasteland. (No really, it is all rusted out...that orange color comes from iron oxide, aka rust)

Re:What about dropped packets? (1)

gestalt_n_pepper (991155) | more than 3 years ago | (#37197898)

I think it's safe to use UDP on this one. They're pictures. Mostly. A bit lost here. A bit lost there. No worse than a few dropped pixels. Sorta like Rick Perry or Palin. Just a little fuzzy around the edges.

Re:What about dropped packets? (2)

grumling (94709) | more than 3 years ago | (#37199180)

Lose a bit here, a few dropped pixels there and you end up with the "Face On Mars." [sciencemaster.com]

I'd like us to get as much non-corrupted data as possible. Helps keep the kookie insane theory folks from getting any traction.

Re:What about dropped packets? (1)

Chris Burke (6130) | more than 2 years ago | (#37207046)

Helps keep the kookie insane theory folks from getting any traction.

Ha ha ha! Yeah right! Okay, maybe a little bit, but it's kinda like dropping a single sandbag of rationality on your front porch as the tsunami of crazy comes barreling towards shore.

At least that's how I felt once I saw that there were some theories going around that the SDO had proven that there were alien spaceships shootin' lazors at the sun, and Jupiter-sized comets in the inner solar system, based on the noise in single images.

Re:What about dropped packets? (1)

MarcQuadra (129430) | more than 2 years ago | (#37200352)

Well there's no point is using IP at all, IP is designed to allow for four billion addresses. What you need in this case is a point-to-point, like a serial cable, not a network stack. Having a network stack would seriously add to the overhead.

And you certainly don't need UDP, or FTP running inside it. Dropped data is a no-no, I believe, but there's no reason you can't just send commands and return data in the raw, then ask for corrupted blocks from the data to be sent again.

It would look like this:

E: Send me file 102.
M: Sends file....
E: Thanks, now send me sections x, y, and z of that file again because I missed it.
M: X, Y, Z...
E: Thanks, now delete the file, point the camera ten degrees left, and take another picture.

How do you know if the data is corrupt? Well you do CRC checking on the wire, and you split all file transfers into chunks and include hashes with them. The chunks need to be right-sized so there aren't too many retransmissions, but big enough not to incur massive latency and overhead.

Re:What about dropped packets? (1)

kvezach (1199717) | more than 2 years ago | (#37202598)

Given their rather long latencies from speed-of-light delays, they might be using forward error correction to fix errors ahead of time. This works more or less like PAR files in that if less than a given fraction of the bits are corrupted, the data can still be recovered without problem, and that would seem to be much quicker than having to do a SYN/ACK type "Hey, these don't CRC out right, give me them again" scheme.

Re:What about dropped packets? (1)

Co0Ps (1539395) | more than 3 years ago | (#37198106)

You calculated the expected noice and simply add enough error correcting redundancy to deal with it. You can use this for example:

https://secure.wikimedia.org/wikipedia/en/wiki/Reed%E2%80%93Solomon_error_correction

Re:What about dropped packets? (3, Interesting)

serviscope_minor (664417) | more than 3 years ago | (#37198420)

eeek.

I expect that they use LDPCC, not Reed-Solomon error correction these days. Good LPCCCs get amazingly close to the shannon limit. Just crank down the rate a bit and watch the BER disappear.

GigE and greater also use LDPCC.

YMMV (2)

ThatsNotPudding (1045640) | more than 2 years ago | (#37203650)

I expect that they use LDPCC, not Reed-Solomon error correction these days. Good LPCCCs get amazingly close to the shannon limit. Just crank down the rate a bit and watch the BER disappear. GigE and greater also use LDPCC.

LOLOMGWTFBBQ

Re:What about dropped packets? (1)

WindBourne (631190) | more than 3 years ago | (#37199676)

While I do not recall all that was done, TCP was re-written slightly to handle that. It really proves the power of abstraction thinking.

Re:What about dropped packets? (0)

Anonymous Coward | more than 2 years ago | (#37210556)

A NAK-based RLP?

http://en.wikipedia.org/wiki/Radio_Link_Protocol

Not "faster" but "higher data volume per second." (1)

gestalt_n_pepper (991155) | more than 3 years ago | (#37197836)

If they can make it faster, I'd be pretty impressed. That dang light speed limit really bugs me.

Chicken meets egg.Y (3)

tetrahedrassface (675645) | more than 3 years ago | (#37197920)

Nice planning on the communication system. Nice to see good solid planning, development and R&D. It's what NASA is good at. They also design pretty good rockets, rockets that used to take us places. Now that we have a better network, lets build the SLS and quit relying vaporcraft to get us there. Let,s quit cutting funding, and make it a priority to travel to are causing a brai Mars. We put a human on the moon and can do it again. The SLS can get us there.. we still have the brain power to go to Mars, but our politicians and misguided and overly hopeful privatization plans.... Less than one tenth of one percent of our budget is spent on space... For all of you wanting to save money, if privatizing space makes sense, why not privatize our national security, epa, and social security?? We need a heavy lifter!

Re:Chicken meets egg.Y (1)

tetrahedrassface (675645) | more than 3 years ago | (#37198154)

Pecked this out on a motorola android with a broken screen.. sue me for the errors.

Re:Chicken meets egg.Y (1)

fotoguzzi (230256) | more than 2 years ago | (#37200344)

I would have had more sympathy if you were connected from Mars over dialup.

Re:Chicken meets egg.Y (0)

Anonymous Coward | more than 2 years ago | (#37201616)

I like it all, except the idea of setting foot on Mars. Colonizing in Mars' orbit would be cool, but once we're out of the gravity well, we'd do well to stay there.

Faster speeds through space than here in US (0)

Anonymous Coward | more than 3 years ago | (#37198114)

As the US internet speeds lag, leave it to NASA to show that they can communicate faster with other planets.

Re:Faster speeds through space than here in US (1)

flimflammer (956759) | more than 3 years ago | (#37198628)

At least we don't have to deal with1,200,000ms latency.

SETI implications (1)

seyfarth (323827) | more than 3 years ago | (#37198138)

So we have finally realized that lasers make sense for long-distance communications. Isn't this likely to have been realized by aliens a long time ago? I think this is why SETI hasn't found alien signals. The aliens use laser or possibly something better. We are unlikely to detect any civilizations more advanced than our own over radio.

Re:SETI implications (1)

Dr. Eggman (932300) | more than 3 years ago | (#37198422)

You can't take back what you broadcast. Radio wave communication is sufficiently simple that it's not all together unlikely other civilizations wouldn't have at least used it at some point. Sure, eventually they may move beyond it. However, if we're receiving their radio signals just now, it's quite plausible they are now far more advanced than us. But, at the same time, in the time it takes for the signals to reach us (assuming they're even powerful enough to not get lost in the background) they could have easily wipe themselves out.

Not faster (1)

geekoid (135745) | more than 3 years ago | (#37198144)

Higher bandwidth doesn't mean faster, it means more data over the same time. Both means are still limited by the speed of light.

Re:Not faster (1)

danlip (737336) | more than 2 years ago | (#37210724)

So you don't say that your network is "faster" or "slower" when it has more or less bandwidth? Most people do. Faster means it takes less time to communicate the same amount of data. Lag/ping time is important to, and you are right that this doesn't help those numbers, but I think it can still be called faster.

Yeah, just my luck (0)

Anonymous Coward | more than 3 years ago | (#37198152)

The most rural american internet connection gets a bandwidth upgrade, how come we can't get 100Mbps in the states.

A little premature, don't you think? (1)

Jay L (74152) | more than 3 years ago | (#37198174)

We don't even know if the Martians use big-endian encodings yet.

What's new here? (1)

Nightwraith (180411) | more than 3 years ago | (#37198314)

I'm not sure what the big deal is. I've seen this decades ago.
Granted the end points were stationary relative to each other and the distances were slightly shorter.

But all you'd really need is a 50MW laser and a phase-conjugate tracking system.

Re:What's new here? (1)

GumphMaster (772693) | more than 2 years ago | (#37200188)

When you work out where to get 50MW from when you are solar powered and in orbit around Mars let me know. I'd love some of that action for my roof :)

Re:What's new here? (1)

danlip (737336) | more than 2 years ago | (#37210788)

Tsk tsk, it was a 5 MW laser. And the energy comes in chemical form, but it's a one shot thing. Put simply, in deference to you, it's like lasing a stick of dynamite.

Re:What's new here? (0)

Anonymous Coward | more than 2 years ago | (#37201328)

"And the trees across the Quad!"

Re:What's new here? (1)

Nyeerrmm (940927) | more than 2 years ago | (#37201462)

The thing about space (besides that its big) is that it makes almost everything harder. Every spacecraft is power starved, so simply adding power is not usually a possibility -- the key is going to be getting a higher data rate for the same amount of energy, mass and operational complexity compared to radio comm.

Even more importantly: high powered lasers put off a lot of heat. On Earth, we've gotten pretty good at disposing of heat -- convection or conduction work great. Unfortunately, in space, you can only radiate the heat away -- thermal management of a spacecraft is a surprisingly difficult proposition. A high-powered laser makes thermal management all the more difficult, and you'll notice that lasers in space are in fact quite rare for that reason.

This is why an engineering demonstration is important -- it helps us work out these issues without risking a $400M Mars mission. I'm working on the next orbiter (MAVEN) right now, and our job would be much easier if we had laser comms to transmit back a lot of the telemetry we'd like to get.

Money-making opportunity? (2)

istartedi (132515) | more than 3 years ago | (#37198468)

Any possibility of licensing spectrum to the Russians, the Chinese, or other countries that want to send probes to Mars? Fractional T-1 to Mars in exchange for a Soyuz ride or something...

Re:Money-making opportunity? (1)

ThePeices (635180) | more than 3 years ago | (#37199060)

You dont need a license to transmit laser light for data transmission.

Re:Money-making opportunity? (1)

istartedi (132515) | more than 2 years ago | (#37200422)

You dont need a license to transmit laser light for data transmission

You do need a license to relay weaker signals from the surface of the planet up to an orbital platform controlled by a 3rd party.

If your probe can send signals up to an orbital platform you don't need as much power (lasers do attenuate over distance). There might be a significant weight penalty for a direct Earth-Mars laser with each probe. If you save the weight, you can send more probes to different locations instead of launching your own BFLaser with each probe.

If we had an orbital relay station with excess bandwidth, it would make sense to sell it to somebody. From their PoV, it would make sense to buy the bandwidth because they could launch more probes or concentrate on something other than the communication infrastructure (comparative advantage, etc.).

IANACost analyst for space agencies, so maybe the math doesn't work. It's just an idea. Hopefully I've fleshed it out to the point where it makes sense now.

Re:Money-making opportunity? (0)

Anonymous Coward | more than 2 years ago | (#37203714)

I'd put money on laser light coming from Mars diverging quite a bit over a few million miles. Maybe so much that the beam width at earth would be greater than the angular diameter of Mars itself.

_that being said_, if anyone else wants to put up a similar network, they'd just use a different color laser.

Re:Money-making opportunity? (1)

Shatrat (855151) | more than 2 years ago | (#37204902)

I believe he means to lease a dedicated circuit. Too many wireless stories have confused Slashdot readers about how telecom works.

Re:Money-making opportunity? (1)

Sockatume (732728) | more than 2 years ago | (#37203788)

That's not a bad idea, actually. Put one transmitter on Earth and one relay around Mars* and pool the resources of the transmitting nations on improving bandwidth and reliability. Then the Mars relay switches to high-bandwidth (relatively) short-range radio for the last leg.

*Realistically, a redundant set

Sounds fast! (1)

gregthebunny (1502041) | more than 3 years ago | (#37198964)

My home Internet connection is still only 4 Mbps. I'm totally jealous of those Martians right now. Also, "in about like"? Seriously, who edits these summaries? A twelve-ye... never mind.

Link to the Engineering? (1)

grumling (94709) | more than 3 years ago | (#37199260)

Anyone have a link to the details? I'd love to see how they solved problems like atmospheric disturbances and dispersion. A cartoon of a satellite doesn't tell us jack shit about how it works.

Re:Link to the Engineering? (1)

Anonymous Coward | more than 2 years ago | (#37201114)

The details in the proposal are probably
a) still proprietary, until the task order is issued
b) probably, to a certain extent, subject to export controls

But, in general, Space Laser Comm has been around quite a while (Lincoln Labs at MIT has done a lot of work for USAF on this).

They use pulse position modulation and avalanche/single photon kinds of detectors. It doesn't take a very big telescope on either end (and especially for Dave's project, where they're in LEO)

Think of the astronauts! (2)

teddaman (854135) | more than 3 years ago | (#37199452)

Is this bi-directional? If I'm going to spend a year going out there I'm sure as hell going to download some "images" from earth!

Nuts (1)

WindBourne (631190) | more than 3 years ago | (#37199618)

My mod points just expired. You are SOOOOOO right on the money. If we are going to the moon, asteroids, Mars, etc, we really need big 2-way comm (will not be fast, but pipe can be big).

Misconception (0)

Anonymous Coward | more than 3 years ago | (#37199818)

Faster != bandwidth++;

Radio communications in the frequency ranges that are currently used are pretty nigh on close to the speed of light. Sure there will be a slight increase in "speed" but it will unlikely be more than a few seconds difference at such a short distance in light travel.

TFA is referring to bandwidth.

The line should read "which will allow them to provide greater means of communications from Mars"

Ansible (0)

Anonymous Coward | more than 2 years ago | (#37201230)

First this, next, an Ansible.

MRO misinformation (0)

Anonymous Coward | more than 2 years ago | (#37201584)

There's some misinformation here. MRO will provide downlink rates of as high as 2Mbps peak to MSL, for two short comm passes a Sol on the order of 20 minutes, cutting in at as low as 32kbps at 10 degrees elevation using ADR keyed to at or below a given SNR. And an image takes nowhere near 90 minutes to downlink, not even close, not even single HiRise images. The highest def images on MSL are 1600x1200 and clock in at under 2MByte, 1 byte to a pixel. I'm not sure where these inflated figures come from.

ping (1)

jlebrech (810586) | more than 2 years ago | (#37202634)

latency will suck though

Relativity (1)

rdnetto (955205) | more than 2 years ago | (#37202922)

I haven't read the article, but I'm pretty sure the 5 minutes only refers to how long it will take the data to be be sent, not received. Latency on interplanetary communications is a bitch.

Average distance between Earth and Mars: 230 * 10^6 km (from Wikipedia)
230 * 10^6 km / c = 12.78 minutes (via Google)

The jargon already shows the suits have taken over (1)

D4C5CE (578304) | more than 2 years ago | (#37203178)

These crosscutting flight demonstrations were selected because of their potential to provide tangible, near-term products and infuse high-impact capabilities into NASA's future space exploration and science missions. By investing in high payoff, disruptive technologies that industry does not have in-hand today, NASA matures the technologies required for its future missions while proving the capabilities and lowering the cost for other government agency and commercial space activities.

OIC, they've hired an MBA... ;-)

just a thought... (0)

Anonymous Coward | more than 2 years ago | (#37207732)

Wouldn't a disruption in the integrity of the laser beam disrupt all communications?

So anything that got in the way of the laser would get in the way of communications?

Mars' Internet (1)

Bearded Frog (1562519) | more than 2 years ago | (#37209018)

Great Mars has internets that are four times faster than my home connection now. I wish I was martian.

asteroids! (1)

recharged95 (782975) | more than 2 years ago | (#37209548)

Who would have figured that packet collisions will likely be caused by asteroids and meteorites.

12x faster than my home ADSL... (0)

Anonymous Coward | more than 2 years ago | (#37211930)

...and I live a few miles from the nearest telephone exchange

Welcome to 21st Century rural Britain...broadband officially slower than interplanetary communications!

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?