SETI bioastro: Pioneer 10 Status for May 3, 2001

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From: Larry Klaes (
Date: Thu May 03 2001 - 06:09:27 PDT


Pioneer 10 distance from Sun : 77.70 AU

Speed relative to the Sun: 12.24 km/sec (27,380 mph)

Distance from Earth: 11.75 billion kilometers (7.30 billion miles)

Round-trip Light Time: 21 hours 46 minutes

Good News!! Pioneer 10 lives on. At GMT 17:27:30, Saturday, 4/28/01, the signal from Pioneer 10 was received at station 63 in Madrid, the first time since August 5/6 of last year.

So it appears that Pioneer 10 has life, albeit in another mode - i.e., only in a two-way coherent mode. We have been listening for the Pioneer 10 signal in a one way downlink non-coherent transmission mode since last summer with no success.

We therefore conclude that in order [for Pioneer 10] to talk to us, we need to talk to it. This means from now on, we need two-way round-trip light time (RTLT) passes to allow the Deep Space Network (DSN) to send up a strong stable signal to lock up with a coherent downlink signal.

The status of the Geiger Tube Telescope instrument (James Van Allen, P.I.) is on. We have not reduced the data from this current contact yet, but believe that it has been received. Due to power considerations, this is the only instrument that has been powered on for the last 4 years.

Last month, we successfully processed tracks, previously thought null. The scientific data on the 5 and 6 August 2000 passes of Pioneer 10 were sent to Dr. Van Allen, who reported clean data. The cosmic ray intensity was identical within statistics to that on DOY 190 (7/9/00), the date of the last maneuver. There was no further decrease, indicating that the Solar wind boundaries have yet to be reached.

Larry Lasher, Pioneer Project Manager

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