John Stoffel wrote:"This was a great help, but now that we have more
and more deep space probes, and with the DSN network starting to get
overloaded, how would you make it easier to send probes so that they
can do more of their own navigation work?
Would it help to put some sort of navigation beacon on the surface of
the target planet/moon? Something that the approaching probe could use
for it's own orbital insertion maneuvers?
It seems that MCO could have used some way of measuring it's distance
from Mars more accurately, not just the measurement of it's vector in
comparision to Earth.
Now that we have a bunch of orbiters, would it be cost effective to
have some sort of small beacon put onto them so that they can help
other approaches? John"


With respect to youre last question, the Deep space 1spacecraft had the
small deep-space transponder SDST on board, which advanced transponder
technology in an effort to reduce the demand on the deep space network
from traveling space probes.


http://nmp.nasa.gov/ds1/index.html
"Deep Space 1 launched from Cape Canaveral on October 24, 1998.
During a highly successful primary mission, it tested 12 advanced,
high-risk technologies in space. In an extremely successful extended
mission, it encountered Comet Borrelly and returned the best images and
other science data ever from a comet. During its fully successful
hyperextended mission, it conducted further technology tests. The
spacecraft was retired on December 18, 2001.
...ADVANCED TECHNOLOGIES..
http://nmp.nasa.gov/ds1/tech/transponder.html
SMALL DEEP SPACE TRANSPONDER
DS1 validated a small deep-space transponder (SDST), built by Motorola
that combines the receiver, command detector, telemetry modulator,
exciters, beacon tone generator, and control functions into one 3-kg
package. The SDST allows X-band uplink and X-band and Ka-band downlink.
To achieve the SDST's functionality without a new technology
development would require over twice the mass and 4 or 5 individual
subassemblies.
The SDST generates the tones needed for beacon monitor operations,
conceived to reduce the large demand that would be expected on the Deep
Space Network if many missions were in flight simultaneously, as
envisioned by NASA. The SDST continues to operate as planned."

tom