Communications Strategies, How can the Deep-Space Network be improved on? |
Communications Strategies, How can the Deep-Space Network be improved on? |
![]()
Post
#1
|
|
Senior Member ![]() ![]() ![]() ![]() Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 ![]() |
Given the recent news that Cassini will lose some data during the Phoenix landing due to contention for DNS access:
http://www.unmannedspaceflight.com/index.p...ic=4831&hl= It seemed reasonable to create a topic to discuss where the DNS might be going. Jasedm suggested a relay station at the Earth-Sun L2 point, which I think might be discussing (despite the expense) assuming the relay station could use laser communication with space probes, while beaming data to Earth via microwaves. I know that experiments with laser communications were part of the now-abandoned Mars Telecommunications Orbiter, and I know that there was even a recent laser experiment involving Mercury Messenger. http://www.space.com/missionlaunches/060104_laser_comm.html These seem intended to support laser communications with ground-based receivers, though -- something that seems much too risky if remote space probes can't store days of data allowing for multiple retries. Obviously a relay station would have its own risks -- you'd probably need two for redundancy -- and it'd be fabulously expensive, but it might also include quite a few savings as well. I've looked for figures for what the DSN costs to run, but I haven't found them yet. Not sure how large a part of a given mission (if any) is charged to the DSN, but it seems to me that a relay satellite ought to be a good bit cheaper to operate, and for far higher bandwidth. Also, a laser transmitter ought to be lighter and consume less power than an equivalent microwave transmitter. That alone could result in huge savings for outer-system missions. The only time I saw a serious proposal for a laser-to-satellite communications system was in a description of options for the "Grand Tour" that later became Voyager. (Assuming that counts as serious.) :-) With DSN needing more and more maintenance, I wonder if anyone is seriously considering laser for the future. --Greg |
|
|
![]() |
![]()
Post
#2
|
|
![]() Merciless Robot ![]() ![]() ![]() ![]() Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 ![]() |
I proposed relay sats at the Earth-Sun L2 & L4 points here a couple of years back, Greg, but don't want to dig back that far. Turns out that somebody found that the idea dates from at least 1935(!) or thereabouts. Also, lasercomm from the outer solar system rapidly demands inordinate amounts of power due to inverse-exponential losses, so we're not quite there in terms of vehicle capabilities yet.
Not that I'm trying to shoot you down at all. I still really like the idea, think that even good old RF relay spacecraft at the Lagrange points would be immensely useful. The really nice part is that if you also set up a set of geosynchronous intermediate relay sats with crosslinks then you never need to care if the rain in Spain is falling mainly on the plain (to say nothing of the 70m dish)... ![]() -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 19th June 2024 - 07:52 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |
![]() |