Chapter 3 of 8

A ramp, not yet a road

Airbag clearing and rover rollout on 5 July US time / 6 July UTC

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

CAPE CANAVERAL, Fla.
Pathfinder & SojournerAn airbag had helped us land. Now it needed to move out of the way.
NASA
01NASA's catalog records maneuvers to clear an airbag before rover deployment. The team checked the surroundings and prepared a usable ramp. A safe landing and a safe rollout were separate problems.
Sojourner stood up on six wheels before taking the slope to Mars.
02The rover deployed from its stowed position and backed down a ramp. The catalog gives July 6 around 05:40 UTC. NASA Science describes the night of July 5 in US time. Those descriptions do not require two different rollouts.
The twin rovers of NASAa Mars Exploration Rover Mission pose with their groundbreaking predecessor, the flight spare of the Sojourner rover from NASA 1997 Pathfinder mission.
Pathfinder & SojournerSmall wheels reached the ground. The lander stayed where it had landed.
NASA/JPL-Caltech
03Sojourner became the first wheeled vehicle operated on another planet. Pathfinder, renamed the Carl Sagan Memorial Station, remained the imaging, weather and communications station beside it.
The rover's next journey would still depend on the station behind it.
04Sojourner exchanged information with Pathfinder, and the lander relayed rover data to Earth. Moving out onto Mars did not give the rover an independent Earth communications link. That partnership matters all the way to the end of this story.

The big idea

Deployment and communications are part of mobility. A rover can move separately while still relying on another spacecraft to send its evidence home.

Think about it

Which part of a rover mission stops being visible from Earth if its relay station cannot communicate?

In this chapter: Retracting airbags, deployment ramps, six wheels and rover-to-lander radio

Sources: Main record · Mars Pathfinder · NASA Science · 25 Years Ago: Mars Pathfinder Launches to Mars to Deploy Sojourner · NASA

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

Chapter 3 of 8

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