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Interplanetary Network (IPN) Tested
CETS writes "Slim on detail but...USA Today reports of the first test of an Interplanetary Network. 'In a sign of cosmic communications to come, last week mission controllers sent signals to a Mars-orbiting European spacecraft, which relayed the instructions to NASA's Spirit rover on the surface, and a signal was returned to Earth back along the same path.'" NASA also has a press release.
Go ahead - mod this troll... :-)
I mean, good intentions, and kudos to NASA to get that infrastructure up and running, but it will probably take some more years before this really starts to make sense.
I guess it won't be used for routing traffic to gameservers...
-- Power corrupts, but PowerPoint corrupts absolutely.
Does that come before or after pinging the Mons Venus?
I'm looking forward to the day we can slashdot a website on another planet.
SIG: TAKE OFF EVERY 'CAPTAIN'!!
they just MUST use IPv6
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
Wouldn't it be much faster to use a subspace frequency?
zWhat would an EWOULDBLOCK block, if an EWOULDBLOCK could block would? -- me
let's see, we already have:
PAN: Personal Area Network
LAN: Local Area Network
SAN: Storage Area Network
WLAN: Wireless Local Area Network
WAN: Wide Area Network
MAN: Metro-something Area Network
and now:
IPN: Interplanetary Network
can anyone add any more?
get people excited about space exploration. I for one am overwellmed by the string of success. Heck .. I even have NASA TV constantly running on my computer just so I don't miss a press release and to lean more about the rovers. Previously we were limited to bot's being in a "Direct line of sight" with Earth to transmit data. Now with the IPN we can get data faster and more often. KUDO's to NASA and the ESA for great job !
...that they haven't implemented some form of relay satellite over Mars already. I'd think that one satellite in space would remain viable longer than a ground craft, and since it's in space it wouldn't have the dust-on-the-solar-panels problem, the atmospheric barrier problem, or the temperature variance problem. The ground craft wouldn't need to be built to transmit to Earth, just to an orbiting Mars satellite, which would handle the rest, so the landing craft could have engineering to make it more suited to its task rather than concentrate on radioing home.
Do not look into laser with remaining eye.
The bulk of data coming back from the Mars Exploration Rovers comes back through relay sessions through the Mars Odyssey and the Mars Global Surveyor satellites. The orbiters are simply much closer to the rovers than Earth is, the path loss is less, and so the data rates are much higher... and the satellites have direct visibility of earth for much longer and much higher EIRPs to talk to earth with.
A couple of weeks ago they tried the first "interplanetary network" where the sessions were up "live", rather than store and forward.
The really big advantage of this is they'll be able to command the rovers in near-realtime and get answers back right away for much more of the day than direct to earth communications is possible. And with 3 communications satellites above Mars, they are likely to have quite a few communications windows. Expect them to be fairly risk adverse, though, and for it to be several weeks before this is included in their operations.
USA Today, is right, though. The lag time between Earth and Mars is anywhere between 3 and 22 minutes when Earth and Mars are clostest and farthest away from each other in their orbits.
And I think NASA has had plans to incorporate signal relay satellites for some time. Of course, NASA plans to build many more probes/satellites than actually get launched, so we're just now seeing satellites with relay capabilities. There were plans as far back as 1997 to launch a series of satellites whose only purpose was to relay signals from other spacecraft. Interplanetary routers, if you will. However, due to budget cuts, the capability was instead built into satellites with otherwise scientific payloads.
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The IPN and the Internet are two different things.
The IPN does not use TCP or another transmission control protocol because it is simply not possible to acknowledge data/rerequest data if the latency is that big (minutes to days in the solar system).
Martian Email Scam ("my recently deposed president Marvin...")
Movie hax0rz routing their connection "through Mars" to avoid detection
RIAA supoenas Spirit rover
You know, to prevent a Little Green Man-in-the-Middle Attack?
--Leo
The lag time between Earth and Mars is anywhere between 3 and 22 minutes when Earth and Mars are clostest and farthest away from each other in their orbits
And just to make matters worse, you've got to deal with some serious high-gain amplification to "dial them up". Beaming cable over a satellite's easy -- sending it millions of miles away means a lot more power (a scarce commodity on a satellite to begin with) or a much more sensitive antenna on the recieving end. I don't know what the current data transmission rates with the things we sent to Mars, but for reference, the Magellan probe back in the 90's had a transmission rate of 115 - 268.9 kilobits/sec.
It is really amazing to consider that we now have a "spy" satellite orbitting Mars relaying images of the surface back to us on Earth, and that it's sensors are good enough to show us photos of the landing of the rover on the surface. Just incredible. But this technology is still in its infancy -- we've still got decades before we land a man on the planet. This is an amazing page about the Soviet exploration of Venus that may also be of interest.
A phased array is composed of a large number of simple antennas in a regular pattern. Each of the simple antennas is connected to a phase controlling element, usually controlled by a computer. By adjusting the phase of each simple antenna, the array's radiation pattern can be manipulated to form one or more directional beams, without having to move any mechanical parts.
For NASA's application on TDRS, it allows them to simultaneously track and communicate with multiple satellites in low-Earth orbit, with a single electronically steered antenna system.
The trick NASA pulled with the phased array antenna on TDRS was to take the phase controllers off the spacecraft and put them at the TDRS ground station. The TDRS spacecraft takes the output of all the simple antenna elements and retransmits each one to the ground station. The ground station has a magic phasing/combiner box that takes the outputs of all the simple antennas and adjusts the phase of each signal and combines them under computer control. This splits the phased array into two parts, with part in space (simple antenna array) and part on the ground (phasing/combiner/control computer). This removes a big chunk of hardware and complexity from the spacecraft and relocates it to the ground station.
Looking at the TDRS web page, the latest series of TDRS spacecraft (TDRS-H, I, J) have the beam-forming hardware on board the spacecraft, instead of doing it on the ground.
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