I don't think Dawn and Cassini are what you were talking about, right? While both are great missions, I wouldn't classify them as "deep space probes."
Other than Voyagers, is there anything currently out there?? Any plans for such a mission?? (Not that I could see) Seeing as they would be relatively economical, I'm curious as to why we aren't sending them out. Perhaps one every 3 to 5 years (10 years?) so they could effectively form a "relay chain" for data transmission?? Be nice to be doing something while we're waiting for new launch vehicles......
Does anyone know what sort of data transfer rates do we get from Voyagers?
By the way, Buck Rodgers according to TV when I was a kid was launched in 1997 on "America's last deep space probe". So he should be on ice out there somewhere.
The Voyagers are still amazing in terms of data rates.
1) What controls the data transfer rates on the Voyager side? Is it just programming from Earth? I mean how does it "know" to slow down? Is it as simple as a command from Earth "from now on your downlink speed it X kbps?2) Also, I've heard when Earth uplinks the commands to Voyagers we send these packets multiple times each time slightly changing the frequency. Is it still the case? Do we have to cover broader frequency ranges since the spacecrafts are further away?
Speaking of deep space... the IBEX is launching on Sunday to study the heliosphere/termination shock/bow shock ect.... Very interesting stuff.Would there be any value what so ever in launching a few simple probes, maybe 3 or 4, on different trajectories out of the solar system to study the heliosphere at different positions?
Quote from: amaturespacecase on 10/18/2008 05:44 amSpeaking of deep space... the IBEX is launching on Sunday to study the heliosphere/termination shock/bow shock ect.... Very interesting stuff.Would there be any value what so ever in launching a few simple probes, maybe 3 or 4, on different trajectories out of the solar system to study the heliosphere at different positions? IBEX is basically remote sensing--looking at it from very far away. The Interstellar Probe mission that I linked to above is a proposal to send a spacecraft there.To answer your question, yes and no. The heliophysics community ranks a mission to the heliosphere very highly. So there is indeed scientific value. But they would settle for one spacecraft and don't require 3-4. More than one would be great, but they are already asking for a lot simply by asking for one.That said, this is not an easy mission. The flight times to the target distance (200 A.U.) are very long, ranging upwards of 25 years. How do you flight qualify a spacecraft for 25+ years of operation? And of course you have to power it with RTGs. That requires a fair amount of power (because it needs to work at 25+ years). So there is no such thing as a "simple" probe to such a distance. The instruments are relatively simple, but getting out that distance and having everything still work is not.
How do you flight qualify a spacecraft for 25+ years of operation?
Quote from: Blackstar on 10/08/2008 01:45 pmI'm still not quite sure what kind of mission you are referring to, but you should take a look at this:http://interstellar.jpl.nasa.gov/interstellar/probe/index.htmlThanks Blackstar. Amasing... 25bps (bit/sec) data transfer rate... not much at all. No video feeds for us then :-/Does anyone know what sort of data transfer rates do we get from Voyagers?
I'm still not quite sure what kind of mission you are referring to, but you should take a look at this:http://interstellar.jpl.nasa.gov/interstellar/probe/index.html
1) Why not have a chain of probes? The outer does not communicate directly with Earth but with a chaser?2) It's mechanical things that fail. The redundancy comes from having multiple units.
Quote from: Blackstar on 10/18/2008 09:31 pm How do you flight qualify a spacecraft for 25+ years of operation?I guess some RTG's would be flight-qualified now (having served on Pioneer 10/11 or Voyager 1/2. But for most components, I doubt it makes sense to speak of flight-qualifying them. Technology is changing to fast for us to do that. Actually testing a system for a significant length of time means you'd be using systems much older than the current state of the art. It might take a extraordinary effort to keep in production a proven, old system.
2) Redundancy is nice. But no budget is the reality. Last time we had more than one probe: MER 2003. Last time before: Voyager 1977. You get the idea.Analyst
True. New Horizons would've been the latest with New Horizons 2 (which would've went to Uranus), but the lack of an available RTG in time for a 2008-09 launch--from what I read 3 years ago--was what prevented the NH2 mission from ever taking place.