Monday

The greenhouse at the crew's Moon outpost hums under its grow lights. Rows of tomatoes, lettuce and beans stretch toward the glass.

Comet bursts in, sketch notebook under her arm. "Mission control wants an app that watches these plants," she says. "Let's build it today!"

Wren kneels beside a drooping lettuce leaf. "Build what, exactly? What do you notice about this row?"

"It looks thirsty," Comet admits. "So the app should water it?"

Nova glides down from the rafters, her cyan lights glowing. "Would you like a hint?" she asks. "Ask the people who tend these plants before you build anything."

Comet turns to you. "You are our developer. Where do we start?"

Beacon is the crew's running project for the next twelve weeks.

Beacon will watch the greenhouse plants and relay readings, photos and messages back to mission control.

It is a paper prototype. You will design it, write it in pseudocode, test it and review it, all on paper.

The Moon greenhouse and its relay network are story fiction. The computer science you learn along the way is real.

This course is unplugged. You never need an app, a website or an account.

A computing innovation includes a program as a key part of how it works.

It can be physical, like a self-driving car. It can be software, like a picture editing program.

It can also be an idea, such as shopping online.

The purpose of a computing innovation is to solve a problem, or to let people pursue interests through creative expression.

A program is a collection of statements that does a specific task when a computer runs it. People also call a program software.

A code segment is a collection of statements that is part of a program.

A program needs to work for a variety of inputs and situations, not just one.

Beacon must work when the water is low, when it is high, and everywhere in between.

Strong start, developer. Tomorrow the crew interviews the greenhouse team.