1 Game Letter

To: Zero Robotics Competitors

Greetings, Space Engineers! As part of an extended research campaign on the International Space Station (ISS), NASA and the Zero Robotics team are calling on your advanced coding and robotics skills. The ISS crew relies on Astrobee—an autonomous, free-flying robotic platform—to support critical operations in microgravity. This year, your challenge is to program Astrobee to manage a sustainable vegetable-growth system aboard the station.

Your robot must navigate in microgravity, execute precise maneuvering, and coordinate a full agricultural workflow: planting seeds, watering them on schedule, harvesting mature crops, and clearing failed plants. Astrobee must also allocate time efficiently, prioritize tasks dynamically, and respond to real-time mission updates from the crew.

Astronauts will specify which crop type they need using hand gestures. Your robot may visit the Astronaut Zone to detect this gesture—however, only one robot may enter the zone at any given time. Successfully identifying and fulfilling these requests can earn valuable bonus points.

Key Mission Considerations

The team that earns the most points wins. This is your opportunity to prove your engineering skills and claim the title of Best Space Robotics Team!

2 Background

Welcome to the Zero Robotics Game Manual for the 2026 High School Tournament: Galactic Garden! This guide will equip you with the essential knowledge and rules to participate. 

As a participant, you're joining a community that directly contributes to research conducted on the International Space Station (ISS). Your involvement not only enhances your programming and robotics skills but also supports real-world space science initiatives. To provide you with a solid foundation, this manual includes background information on the history and current advancements in key topics relevant to the Galactic Garden challenge.

We encourage you to delve into this manual thoroughly to maximize your understanding and performance in the competition. Your journey in Zero Robotics is not just about coding; it's about pushing the boundaries of what's possible in space exploration.

Human Space Exploration

With the development of space technology in the 20th century, we had the opportunity to send machines, animals, and humans to outer space and explore the universe. The first human in space was Yuri Gagarin from the Soviet Union in 1961. Since then, over 600 people from 43 nations have traveled to space. As of December 2025, 10 people are currently living and working in space. Human space exploration helps us understand the universe's history and provides a platform for us to grow, experiment, and improve our lives.

The International Space Station (ISS) is the largest human-made object that orbits Earth. Since 2000, it has evolved from an outpost into a competent microgravity laboratory that hosts scientific investigations and demonstrations in various fields. The ISS has orbited Earth for 25 years, and as of December 2025, over 290 astronauts have visited it. 

Growing Plants in Space

Plants are essential for sustaining human life during space missions! On extended journeys, farming plants provide astronauts with fresh, nutritious food and a comforting connection to Earth. NASA has initiated several innovative projects aboard the International Space Station (ISS) to study and enhance plant growth in microgravity.

Middle and high school students have played a pivotal role in advancing space plant research through the Growing Beyond Earth program. Launched in 2015, this classroom-based citizen science project, developed by Fairchild Tropical Botanic Garden in partnership with NASA, involves conducting experiments that simulate conditions aboard the ISS. By cultivating various plant species and collecting data on their growth, students provide valuable insights that help NASA scientists select crops suitable for space cultivation. To date, over 10,000 students across the United States have participated, contributing to NASA's research on growing plants in space. 

One of NASA's notable projects is the Vegetable Production System, affectionately known as "Veggie". Established in 2014, Veggie is a plant growth unit that enables astronauts to cultivate various crops, including lettuce and zinnias, directly on the ISS. This system not only supplies fresh produce, but also serves as a platform to study plant growth in space.

Building upon Veggie's success, the Advanced Plant Habitat (APH) was introduced in 2017. The APH is a fully automated growth chamber equipped with a series of sensors and LED lights to control environmental conditions. This setup enables scientists to conduct detailed experiments on plant behavior in space, advancing our understanding of how plants adapt to microgravity. 

Researchers have identified that light plays a crucial role in plant development. Experiments have shown that many plants thrive under red and blue light, prompting the use of specialized LED lighting systems in space-based plant growth chambers to optimize photosynthesis. Gravity, or the lack thereof, significantly influences plant growth. In microgravity, plants experience changes in leaf development and cellular structure. For instance, experiments have shown that microgravity affects the distribution of calcium within plant cells, a vital element for growth. Fortunately, these calcium fluctuations did not hinder overall plant growth.

Through these collaborative efforts and ongoing research, NASA continues to explore and overcome the challenges of growing plants in space, paving the way for sustainable long-term human missions beyond Earth!

Robotics in Space

Robotics in space will not only help overcome challenges humans may face, such as the lack of an atmosphere, but also make the best use of human time by having robots assist with various tasks. Two main areas of interest for space robotics are microgravity and planetary robotics. Microgravity robotics is the manipulation and mobility in microgravity environments, such as the International Space Station. Planetary robotics is robotics manipulation and mobility on or near the surface of a planet, such as Mars and the Lunar surface.

Astrobee Robot

Astrobee is a new generation of free-flying robots designed to assist astronauts aboard the International Space Station (ISS). It replaces the SPHERES robots, which served as robotic test platforms on the ISS for over a decade, with significant hardware and software upgrades. The three Astrobee robots—Bumble, Queen, and Honey—were developed by NASA to reduce the time astronauts spend on routine tasks, allowing them to focus on activities that require human expertise.

Astrobee robots can operate autonomously or be remotely controlled by astronauts, flight controllers, or researchers on the ground. They can perform tasks such as taking inventory, documenting experiments with built-in cameras, and collaboratively moving cargo. Additionally, the system serves as a research platform, enabling scientists to conduct experiments and develop new technologies for future space missions. Robots like Astrobee are expected to play a critical role in future deep-space missions, acting as caretakers for spacecraft when humans are away.

Learn more about Astrobee here! 

Legacy and Future Applications

Astrobee builds on the legacy of the SPHERES robots, incorporating lessons learned to create a more advanced system. It is modular and can be customized to carry experimental payloads, enabling diverse scientific research. Since the system can be upgraded over time, it provides a versatile platform for advancing space robotics.

As NASA prepares for future missions to the Moon and beyond, robots like Astrobee will play a vital role. They have the potential to act as autonomous caretakers, monitoring spacecraft systems and ensuring smooth operations during crew absences.

Ground Robotics Demo

This year, the Zero Robotics Competition Finals will be run and tested through simulation and a ground-robotics demonstration. On February 21st, instead of a purely virtual championship, we'll be running a ground robotics analog, and you'll have the chance to deploy your code onto real hardware, including drones and underwater robots.

That's right: your algorithms won't be stuck inside a simulator. They'll be navigating physical space, reacting to real-world conditions, and carrying out your strategies live. Few student robotics competitions offer something this hands-on, and it's your moment to shine.

We're also excited to continue a tradition from previous years. In the past, we've partnered with the Critical Matters group at the MIT Media Lab to run the Finals using new robotics platforms. 

3 Game Introduction 

Guide Astrobee to manage crops across 6 plots, respond to astronaut requests, and compete against another robot.

Game Duration: 240 seconds (4 minutes)

4 Gameplay Concepts

Garden Layout

Click to see an overview of the game setup in 3D space

Movement

Coordinate system: X = Left/Right, Y = Forward/Back, Z = Up/Down

game.MoveTo(x, y, z);
game.MovePlot(id);           // id = 1-6
game.MoveAstronaut();
game.LeaveAstronaut();
game.MoveWatering();
game.MoveToHome();

Scoring System

Your total score combines multiple components—active robots score better!

Diminishing Returns System

Strategic crop diversity is rewarded! Each time you harvest the same crop type, subsequent harvests of that crop yield fewer points:

Crop Types

Planting Crops

Each robot can plant crops at any of the six garden plots using:

game.PlantCrop(plotID, cropID);

Where:

• plotID is 1, 2, 3, 4, 5, or 6
• cropID is 1-6 (see Crop Types table above)

The robot must move to the correct plot using game.MovePlot() and be physically at that location before calling game.PlantCrop().

Watering Crops

To water a crop, the robot must first move to the Watering Zone. Note that only one robot may use the Watering Zone at a time—if the other robot is already there, your robot will not complete the move.

game.MoveWatering();
game.FillWateringCan();  // fills 6 units of water

To water a planted crop, use:

game.WaterCrop(plotID);

Crop Growth and Harvesting

Crops follow a strict care timeline. Use this sequence to maximize harvest success:

• Watering can be done immediately after planting
• Both waterings must happen within 60 seconds of planting or the crop will fail
• Water #2 and Harvesting can only happen after the growth times have passed

Crop Cycle Timing Examples

Min Cycle Time = Plant + Water#1 + GrowthTime + Water#2 + GrowthTime + Harvest (plus movement)

After the growth time has passed, harvest using:

game.HarvestCrop(plotID);

If a crop is harvested too early, no points are earned and the crop disappears. To prevent this, make sure enough time has passed since the last watering.

Crop Failures and Shovel Use

If a plant is not watered twice within 60 seconds of planting, it fails and must be removed. Steps to remove a failed crop:

game.MoveToHome();        // Go to your home position
game.GrabShovel();        // Pick up the shovel
game.MovePlot(plotID);   // Go to the failed crop
game.RemoveCrop(plotID); // Remove the dead plant
game.MoveToHome();
game.DropShovel();        // Return the shovel

You must be holding the shovel to remove a crop.

Movement and Exploration Stats

Track your robot's activity with these functions:

Battery and Movement Efficiency

Every movement uses battery power. Battery is not explicitly limited in gameplay; the remaining battery percentage affects your final score. Avoid unnecessary movements to conserve energy, and refrain from carrying heavy objects, such as the shovel!

End of Match

Each match lasts 240 seconds (4 minutes). When time expires, robots must stop all actions. The final score is computed based on crops harvested, bonus crop points, movement/exploration bonuses, and remaining battery.

Astronaut Bonus Sequence System

The astronaut is your best friend! Visit frequently to:

1. Get +5 points per bonus crop assignment (max 3 times total)
2. Receive a bonus crop assignment (+50% on harvests of that crop)

How It Works

• The astronaut offers a sequence of 3 different bonus crops
• Each bonus crop allows 1 harvest at +50% bonus, then advances to the next
• This promotes crop diversity—you harvest 3 different bonus crops!
• Visit astronaut again after harvesting to confirm each new bonus and get another +5 points!
• Complete all 3 bonus crops to earn an additional +10 points!

Example Sequence

Visit 1: "Your bonus crop is Tomato!" (+5 points for assignment)
   -> Harvest Tomato x1 (+50% bonus)
   -> Bonus advances to next crop

Visit 2: "Your new bonus crop is Melon!" (+5 points for assignment)
   -> Harvest Melon x1 (+50% bonus)
   -> Bonus advances to final crop

Visit 3: "Your final bonus crop is Blueberry!" (+5 points for assignment)
   -> Harvest Blueberry x1 (+50% bonus)
   -> ALL BONUS CROPS COMPLETED! +10 bonus points!

Astronaut API Functions

game.MoveAstronaut();              // Move to astronaut zone
int bonus = game.GetBonusCrop();  // Returns crop ID 1-6, awards +5 pts
game.LeaveAstronaut();             // Exit astronaut zone

5 Advanced Features

Sprinkler System

Sprinklers provide automated watering at a plot, freeing your robot to do other tasks. Once deployed at a plot, the sprinkler will automatically water any crop planted there at a set interval. Each sprinkler is stationary—it stays at the plot where you deploy it.

Sprinkler Example

// Buy and deploy a sprinkler at plot 1
game.BuySprinkler();           // -10 pts
game.MovePlot(1);
game.DeploySprinkler(1, 1);    // Deploy sprinkler #1 at plot 1
game.SetSprinklerInterval(1, 10);  // Water every 10 seconds
game.EnableSprinkler(1);

// Now plant a crop - the sprinkler will water it automatically!
game.PlantCrop(1, 5);  // Blueberry at plot 1
// Robot can now leave - sprinkler handles watering!

Space Tractor System

The Space Tractor is a modular upgrade system that enhances your robot's farming capabilities. You must first unlock the base tractor, then you can purchase attachments that provide special abilities. Attachments are add-ons to your robot—they travel with you, not stationed at plots.

Tractor API Functions

Tractor Example

// Unlock tractor and fertilizer attachment
game.UnlockTractor();       // -25 pts
game.UnlockFertilizer();    // -20 pts, gives 5 uses

// Plant a melon and speed up growth with fertilizer
game.MovePlot(1);
game.PlantCrop(1, 6);       // Melon (normally 12s growth)
game.WaterCrop(1);
game.ApplyFertilizer(1);    // Now only 6s growth time!

6 API Reference

Movement

Basic Operations

Sprinkler System

Space Tractor System

Getters

Movement & Exploration Stats

7 Strategy & Scoring

The goal of Galactic Garden is to earn the highest total score by planting, watering, and harvesting crops effectively while staying active. Each student programs one Astrobee robot and competes head-to-head against another student's code. The robot with the highest total score at the end of the match wins.

Final Score Formula

Scoring Summary

Costs Summary

Tips for Success

1. Visit astronaut early & often — +5 pts per visit + bonus crops
2. Keep moving — 0.5 pts/meter adds up
3. Explore all 6 plots — 12 pts exploration bonus
4. Diversify crops — Avoid diminishing returns
5. Fast crops early — Blueberry (3s), Strawberry (5s)
6. Complete all 3 bonus crops — +10 completion bonus

Sample Strategy Code

void loop() {
    // PRIORITY 1: Visit astronaut early for bonus crop and +5 points!
    game.MoveAstronaut();
    int bonus = game.GetBonusCrop();  // +5 points just for visiting!
    game.LeaveAstronaut();

    // PRIORITY 2: Explore all plots for exploration bonus
    // Plant diverse crops for diminishing returns strategy
    game.MovePlot(1);
    game.PlantCrop(1, bonus);  // Plant the bonus crop!
    game.WaterCrop(1);

    game.MovePlot(2);
    game.PlantCrop(2, 5);  // Blueberry (fast!)
    game.WaterCrop(2);

    // Explore more plots!
    game.MovePlot(3);
    game.PlantCrop(3, 3);  // Strawberry
    game.WaterCrop(3);

    // Refill water
    game.MoveWatering();
    game.FillWateringCan();

    // Continue farming cycle - keep moving!
    game.SetWait(3);  // Wait for blueberry to grow
    game.MovePlot(2);
    game.WaterCrop(2);  // Second watering

    game.SetWait(3);  // Wait for harvest
    game.HarvestCrop(2);

    // Visit astronaut again after harvesting bonus crop!
    // Get the next bonus crop in sequence and another +5 points
    game.MoveAstronaut();
    bonus = game.GetBonusCrop();
    game.LeaveAstronaut();

    // Check stats
    float dist = game.GetDistanceTraveled();  // Movement bonus!
    int plots = game.GetPlotsExplored();      // Exploration bonus!
}

Gameplay Summary

• Objective: Plant, water, and harvest crops while maximizing movement, exploration, and strategic astronaut visits.
• Competition: Only one robot (per match) is active and competes head-to-head against another student's robot code.
• Astronaut Zone: Visit (only one robot at a time) to receive +5 points and detect the bonus crop sequence.
• Watering Zone: Shared resource—only one robot may be in the Watering Zone at a time.
• Battery Score: Remaining battery at the end of the match is multiplied by 0.05 and added to your total score.

8 Code Submission

9 Resources & Guidelines

Key Dates

Piazza

AI Usage

ChatGPT and AI tools are allowed. Please document how you used them in your code write-up.

10 Tournament Rules

• MIT/ZR can use/publish submitted code
• Report bugs immediately
• No manipulating scoring or accessing restricted info
• Code must be written by students only
• No exploiting bugs or unintended features

11 Quick Reference

Blueberry:  3s / 3pts   Strawberry: 5s / 5pts
Tomato:     6s / 6pts   Cabbage:    8s / 7pts
Potato:     9s / 8pts   Melon:     12s / 11pts

Harvest:     Base × (0.75)^count
Bonus crop:  +50%
All 3 bonus: +10 pts
Astronaut:   +5 pts × 3 max
Movement:    +0.5 pts/meter
Exploration: +2 pts/plot (max 12)

game.MovePlot(id)     game.PlantCrop(plot, crop)
game.WaterCrop(plot)  game.HarvestCrop(plot)
game.MoveAstronaut()  game.GetBonusCrop()
game.MoveWatering()   game.FillWateringCan()

12 IDE Patches

This section documents bug fixes and patches applied to the game simulation environment. These fixes are applied server-side and do not require any changes to your code.

13 Change Log