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Re: Determination of c: Pioneer 10 Speaks.



At 12:47 PM 3/3/02, you wrote:
>Here's a useful experimental determination of c for those who have access
>to a big-dish high-power well-steered spatially diverse uplink that can
>pick out a signal that's 2^-71 watts at 16 baud.
>
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Sat, 2 Mar 2002
> From Larry Lasher, Pioneer Project Manager
>Subject: Pioneer-10 30 Year Launch Anniversary Track
>
>Pioneer-10 was successfully contacted today. Yesterday, about 3pm PST a
>200 Kw uplink transmission from Goldstone California, the 70 meter DSN
>antenna DSS-14, was sent to Pioneer-10 and 22 hours later in Madrid Spain
>at the DSN 70 meter antenna DSS-63 the confirmation of contact was
>received. From a distance of 79.7 AU DSS-63 acquired the signal on time at
>about -183 dbm. They spent an hour peaking the signal (-178.5 dbm) and
>then they were able to lock up telemetry at 16 bps at an SNR of -0.5
>db. Tracking continued until the elevation was about 20 degrees but enough
>telemetry was received to verify the state of Pioneer-10. Incidentally,
>the SETI institute also saw the signal from Arecibo in Puerto Rico. For
>years they have used Pioneer-10 as a reference for their investigations.
>
>The spacecraft is still healthy. The power is still sufficient to support
>the loads with the bus voltage at about 26 volts (nominal is 28). The
>uplink from DSS-14 was received by the spacecraft at -131.7 dbm. The
>spacecraft is extremely cold, with many of the temperature readings at the
>bottom of their scales. Two commands were sent yesterday from Goldstone
>and both were confirmed to have been executed by the spacecraft. One
>scientific instrument is still on, the Geiger Tube Telescope, and Dr. James
>Van Allen, the PI, will be happy to hear he has some more data to look at.
>
>Thirty years ago the first mission to explore the outer planets,
>specifically the planet Jupiter, was launched from KSC. Many of the people
>who designed, built and flew the spacecraft have passed on but Pioneer-10
>continues. From ARC and the Pioneer Project we send our thanks to the
>many people at the DSN (Goldstone and Madrid) and JPL who made it possible
>to hear the spacecraft signal again.
>
>Dave Lozier, Pioneer Flight Director
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Brian Whatcott
> Altus OK Eureka!

Howdy,

I have a feeling that the value of c was used to determine the 79.7
AU distance to the Pioneer-10. Therefore you can't turn it around
and find c from this data.

Good Luck,
--
Herb Schulz
(herbs@interaccess.com)


Ah....Herb is probably thinking of round trip transmission time on the data
link.
But time of arrival studies of XRay flares into the Geiger telescope
from mutually perpendicular sources allow position finding, don't they?


Brian Whatcott
Altus OK Eureka!