Chapter 7 of 8

A carrier is not a conversation

Final successful data on 27 September and later carrier detections in October 1997

Told in Pathfinder & Sojourner’s imagined voice · the events are real · source

Sojourner Rover Near The
Pathfinder & SojournerOn September 27, the last successful data cycle reached Earth.
NASA/JPL
01The November JPL report identifies that final transmission cycle. Its review of the rover's last science describes an APXS study of a rock called Chimp. We do not invent an acquisition time for that study.
The team kept listening—and detected a carrier again.
02Signals from the auxiliary transmitter were detected on October 1 and October 6. But the team could not recover lander health data. Detecting the radio carrier was not the same as receiving a new picture, a science result or a complete status report.
NASA's Sojourner rover and undeployed ramps onboard the Mars Pathfinder spacecraft can be seen in this image, by the Imager for Mars Pathfinder (IMP) on July 4 (Sol 1).
Pathfinder & SojournerWithout the lander link, Earth could not keep following the little rover.
NASA/JPL
03Battery depletion and deeper day-night thermal cycling were considered probable explanations for the outage. JPL explicitly kept the true cause uncertain. The lander problem also left Sojourner's status unknown.
Did the rover move afterward? The record does not let us watch that ending.
04The team discussed probable backup behavior, but had no observed post-outage rover movement. This story does not turn a prediction about circling into a witnessed final drive. Sometimes the authentic ending contains a question.

The big idea

A radio signal, usable data and a known spacecraft condition are different levels of evidence. Losing a relay can also hide the condition of another machine.

Think about it

Why is hearing a carrier signal not enough to tell whether a rover is still driving?

In this chapter: Main and auxiliary transmitters, lander battery and the rover's relay dependency

Sources: Main record · Mars Pathfinder · NSSDCA Master Catalog

Machine illustration: AI-made. Photos: NASA Image and Video Library, credited on each picture.

Chapter 7 of 8

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