Chapter 3 of 5

Peanuts and a steering burn

Ranger 7 launches, cruises to the Moon and fires its midcourse engine

Told in Ranger 7’s imagined voice · the events are real · source

Ranger 7 took this image, the first picture of the Moon by aU.S.
Ranger 7On 28 July 1964, my Atlas-Agena rocket lifted off from Cape Canaveral.
NASA/JPL
01The launch came after a one-day delay. My rocket first placed me in Earth orbit, then sent me onto a path toward the Moon.
In the control room, the team shared a bag of peanuts.
02After six Ranger failures, the mission team was anxious. Trajectory engineer Dick Wallace brought peanuts into the JPL control room. The small tradition continued after Ranger 7 succeeded.
Guericke Crater as seen by Ranger 7
Ranger 7In space, I turned my solar panels toward the Sun and my antenna toward Earth.
NASA/JPL
03Small cold-gas jets helped adjust my orientation. My solar arrays made electricity, and my high-gain antenna gave me a way to talk with stations on Earth.
A small engine fired for 50 seconds and nudged me toward my target.
04On 29 July, my hydrazine engine made a midcourse correction. A small change in speed and direction far from the Moon could shift my arrival point by many kilometers.

The big idea

A long journey can be steered by small, carefully timed changes, and a team's shared ritual can carry a story of its own.

Think about it

Why does a tiny engine burn far from the Moon change where the spacecraft arrives?

Fact file

Launch
28 July 1964 · 16:50:07 UTC
Atlas LV-3 Agena-B from Launch Complex 12 at Cape Canaveral. A faulty telemetry battery and a ground-guidance problem had delayed the first attempt by a day.
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Earth orbit
192 km parking orbit
The Atlas and Agena first placed Ranger in low Earth orbit. Half an hour after launch, a second Agena burn sent it toward the Moon.
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Midcourse correction
29 July 1964 · 50-second burn
A 224-N monopropellant hydrazine engine made the course correction. The exact burn time and thrust are NSSDCA values; contemporary descriptions sometimes round them.
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Attitude control
12 nitrogen jets · 3 gyros · Sun and Earth sensors
Small cold-gas jets turned the spacecraft so the solar panels could face the Sun and the antenna could face Earth.
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In this chapter: Atlas LV-3 Agena-B, solar arrays, cold-gas jets and a hydrazine engine

Sources: Main record · NSSDCA · Ranger 7 launch and mission profile · NASA Science · Ranger 7 mission overview · NASA History · Lunar Impact (NASA SP-4210)

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

Chapter 3 of 5

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