Mars landscape

LabelMars: Machine Learning Paints a New Portrait of the Red Planet

How AI is unlocking the secrets of Mars by labeling millions of images.

August 8, 2025

Imagine gazing at millions of photographs of Mars – vast deserts, towering volcanoes, ancient riverbeds, and mysterious gullies. Now, imagine meticulously drawing outlines around every boulder, dune, crater, and rock layer in each of those images. This monumental, eye-straining task is the reality for planetary scientists seeking to understand Mars' geology and history. But a groundbreaking project called LabelMars is revolutionizing this process. Using the power of machine learning (ML), it's creating the largest, most detailed labeled dataset of Martian surface images ever assembled, opening unprecedented windows into the Red Planet's past and present.

The Martian Data Deluge and the Labeling Bottleneck

Mars is the most intensely studied planet beyond Earth. Orbiters like NASA's Mars Reconnaissance Orbiter (MRO), equipped with cameras like the High-Resolution Imaging Science Experiment (HiRISE) and the Context Camera (CTX), have snapped millions of high-resolution images over nearly two decades. Rovers add ground-level perspectives. This treasure trove holds clues to water history, climate change, volcanic activity, and potential habitability.

HiRISE Camera

Provides stunning detail (~25 cm/pixel) but covers tiny swaths of Mars.

CTX Camera

Covers vastly more area (~6 m/pixel) but lacks the fine detail of HiRISE.

However, raw images aren't enough. To extract scientific meaning – like mapping the distribution of specific rock types, measuring dune migration, or counting craters to date surfaces – scientists need labeled data. This means identifying and delineating specific features within the images: "This polygon is a crater," "This area is bedrock," "These lines are fractures." Traditionally, this labeling (annotation) is done painstakingly by hand by experts. It's slow, labor-intensive, and limits the scale of analysis possible. This bottleneck hinders our ability to see the "big picture" across the entire planet.

Enter Machine Learning: Teaching Computers to "See" Mars

LabelMars tackles this bottleneck head-on by leveraging computer vision, a field of artificial intelligence (AI) focused on enabling machines to interpret visual information. The core idea is:

Train the AI

Feed an ML algorithm a smaller set of images that have been expertly hand-labeled.

Predict and Scale

The algorithm analyzes new, unlabeled images much faster than a human.

Refine and Expand

Incorporate human feedback to improve the model iteratively.

LabelMars incorporates strategies like "active learning," where the model flags images it's least confident about for human review. Experts correct these, and the improved data is fed back to the model, making it smarter. This iterative loop allows the dataset to grow exponentially while maintaining quality.

The LabelMars Breakthrough Experiment: Scaling HiRISE Labels to the Globe

While LabelMars is an ongoing, large-scale initiative, a pivotal experiment demonstrating its core methodology and power involved bridging the resolution gap between Martian imagers.

Methodology:

  1. Curate Training Data
    Selected regions where both HiRISE and CTX imagery overlapped.
  2. Train the HiRISE Model
    A U-Net deep learning model was trained exclusively on labeled HiRISE images.
  3. Resolution Adaptation
    Used Transfer Learning to adapt the model to CTX's resolution.
  4. Global CTX Labeling
    Processed over 110,000 CTX images covering a massive portion of Mars.
  5. Validation & Active Learning
    Expert-reviewed subset of predictions to refine the model.

Results and Analysis:

Scale Achieved

This single experiment generated labeled data for over 1.5 million square kilometers of Martian surface in the CTX dataset – an area equivalent to Mongolia, achieved orders of magnitude faster than manual labeling.

Accuracy

While not perfect, the model achieved significant accuracy (e.g., >85% for broad classes like bedrock and sand in validation tests). Crucially, it captured spatial patterns and distributions impossible to map manually at this scale.

Scientific Impact
  • Map the global distribution of bedrock exposures vs. sand cover
  • Identify regions rich in specific features for targeted studies
  • Study feature correlations across the planet
  • Quantify changes over time by comparing labels from different times
Martian Imagers Powering LabelMars
Imager Resolution Role
HiRISE ~25-50 cm Provides high-quality training labels
CTX ~6 m Primary target for scaling labels
MRO MARCI ~1-10 km Context for atmospheric effects
Scale of the LabelMars CTX Experiment
Metric Value
CTX Images Processed >110,000
Area Covered >1.5 million sq km
Approx. Model Accuracy 85-92%
Time Savings >100x

Unlocking Mars' Secrets, One Pixel at a Time

LabelMars represents a paradigm shift in planetary science. By automating the laborious task of image labeling, it frees scientists to focus on interpretation and discovery. The resulting massive, searchable datasets empower researchers to:

Conduct Global Surveys

Systematically map geological features across the entire planet for the first time.

Detect Rare Features

Identify small or unusual formations that might be missed in manual searches.

Quantify Changes

Track shifts in dunes, new impacts, or seasonal processes over time.

Train Better Models

The dataset becomes a resource for training more sophisticated ML models.

Enable Citizen Science

Filtered datasets can empower enthusiasts to contribute to discovery.

"LabelMars is more than just a dataset; it's a powerful new lens through which we view Mars. By harnessing machine learning to decode the visual language of the Red Planet, scientists are painting a richer, more detailed, and dynamic portrait of our enigmatic neighbor than ever before."

The dusty vistas captured by orbiting cameras are being transformed into a meticulously annotated atlas, paving the way for the next generation of discoveries about Mars' ancient waters, its dramatic climate shifts, and its potential to have harbored life. The machine learning revolution has truly landed on Mars.

Essential Tools for LabelMars
Tool Category Examples
Martian Imagers HiRISE, CTX, HRSC
Annotation Software QGIS, ArcGIS, LabelMe
ML Frameworks TensorFlow, PyTorch
Core ML Model U-Net (CNN)
Computing Power HPC Clusters, GPUs
Geospatial Tools GDAL, QGIS, geopandas
Key Features Labeled
Bedrock Sand Craters Dunes Fractures Rock Layers
Model Performance

Validation accuracy for major feature classes in the LabelMars CTX experiment.