Chapter 2 of 8

The landing that bounced

Atmospheric entry and airbag landing on 4 July 1997

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

Large boulders are visible in this enlargement of pictures taken by the Imager for Mars Pathfinder (IMP) lander camera on July 4, 1997.
Pathfinder & SojournerOn July 4, our arrival began with a heat shield—not with wheels.
NASA/JPL
01Pathfinder entered the Martian atmosphere directly from its approach trajectory. The shield reduced speed and protected the vehicle. The lander's instruments also recorded information about the atmosphere during descent.
A parachute slowed us. Rockets helped. Airbags took the final impacts.
02The descent sequence handed work from one system to the next. After parachute deployment, the lander hung below the backshell on a tether. Radar measurements helped time the airbags and retrorockets before release near the surface.
The Mars Pathfinder began the journey to Mars with liftoff atop a Delta II expendable launch vehicle from launch Complex 17B on Cape Canaveral Air Station.
Pathfinder & SojournerWe bounced and rolled before becoming a place where science could begin.
NASA/MSFC
03The inflated airbags cushioned the landing loads. NASA summaries differ in their detailed bounce counts and heights, so this illustration is not an exact replay. The documented outcome is clear: the lander came to rest and could operate.
The airbags deflated. The petals opened. A rover was still waiting inside.
04Pathfinder opened its three triangular petals after landing. Solar cells, the camera and other instruments could begin their surface tasks. The airbags had protected the spacecraft—but one of them would now be in the rover's way.

The big idea

Landing is a sequence of different engineering jobs. Protecting a payload during arrival does not automatically make it ready to deploy.

Think about it

Why can't a parachute or an airbag do every part of a Mars landing on its own?

In this chapter: Heat shield, parachute, tether, radar, retrorockets and multi-lobed airbags

Sources: Main record · Mars Pathfinder · NASA Science

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

Chapter 2 of 8

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