Chapter 4 of 5

A patient weather watcher

Long-lived power made repeated measurements possible

Told in Viking 1’s imagined voice · the events are real · source

First Color Image From Viking Lander 1
Viking 1I could keep working without waiting for sunlight on a solar panel.
NASA/JPL
01Two radioisotope thermoelectric generators supplied electricity from heat released by plutonium's natural decay. Rechargeable batteries helped with higher power demands. My energy budget still mattered: useful power did not mean every instrument could run at once forever.
Staying in one place let me notice Mars changing around me.
02My weather instruments measured temperature, wind and pressure. Repeating observations through changing seasons and dust storms helped scientists study an atmosphere in motion. A single exciting landing-day picture could not provide that long record.
This is the first photograph ever taken on the surface of the planet Mars.
Viking 1Even a radio message could become a science instrument.
NASA/JPL
03During the November 1976 solar conjunction, Viking radio links helped test a prediction of general relativity: a signal passing near the Sun has extra travel time. Carefully timed communications could investigate physics as well as carry photographs home.
My short planned visit became a long watch.
04NASA History reports 2,245 Martian sols of Viking 1 surface operations—more than six Earth years. I outlasted the other Viking spacecraft and continued returning weather and imaging data in the monitor mission. I also became known as the Thomas Mutch Memorial Station, honoring the imaging team's leader.

The big idea

Reliable power and repeated observations turn a snapshot into a record. Communications hardware can also make precise scientific measurements.

Think about it

What can a year of weather measurements tell us that one photograph cannot?

Fact file

Surface endurance
2,245 Martian sols
NASA History's reported duration. More than six Earth years; no exact Earth-day conversion or four-Martian-year claim is added.
Source ↗
Power
Two RTGs plus rechargeable batteries
Heat from natural plutonium-238 decay supplies electricity. The catalog's nominal 70 W total and 30 W-per-unit prose are retained as differing descriptions, not a constant-output guarantee.
Source ↗
Radio experiment
November 1976 / solar conjunction
Viking radio links tested the predicted additional travel time near the Sun. Not a proof of every aspect of relativity.
Source ↗

In this chapter: Two plutonium-238 RTGs, rechargeable batteries, weather sensors and radio links

Sources: Main record · Viking 1 Lander · NSSDCA Master Catalog · Viking Spacecraft and Science · NASA Science · 45 Years Ago: Viking 1 and 2 off to Mars · NASA History · Mars: The Viking Discoveries · NASA EP-146 (1977) · The Viking Lander Monitor Mission · JPL Publication 82-107

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

Chapter 4 of 5

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