Get ready before the weekend

1. Make your accounts

1. Create a free account at Earthdata Login. 21 datasets on this site need it for downloads.
2. Get a free key at api.nasa.gov. Do not build on DEMO_KEY: everyone on your network shares its limit, which was 10 requests when checked on October 18, 2026.
3. Save the key in an environment variable, such as NASA_API_KEY. Never commit it to your repository.
4. For rainfall, weather or carbon data (GPM IMERG, MERRA-2, OCO-2), open your Earthdata Login profile and approve the NASA GESDISC DATA ARCHIVE application.

2. Run one test

1. Install the tools: pip install earthaccess requests xarray. Or skip this step and use Colab.
2. Run the test below. It logs in, finds one elevation tile and downloads it.
3. Check that it prints a file path. If it shows an error, look it up in step 3.

import earthaccess

# Asks for your Earthdata Login once, then saves it to ~/.netrc
earthaccess.login(persist=True)

# Find and download one small elevation tile (New York City)
results = earthaccess.search_data(short_name="SRTMGL1",
                                  bounding_box=(-74.3, 40.5, -73.7, 40.95), count=1)
files = earthaccess.download(results, "./test")
print("Downloaded:", files)

3. Fix common errors

401 Unauthorized when downloading

Check your Earthdata username and password. For GES DISC data, approve the NASA GESDISC DATA ARCHIVE application in your profile, then try again.

The search returns 0 results

Write the bounding box as west, south, east, north. Check that your dates fall inside the product's range. Some products arrive months late: final GPM IMERG rainfall lags by about a year.

OVER_RATE_LIMIT or 429 from api.nasa.gov

Replace DEMO_KEY with your own free key.

Downloads are slow on venue Wi-Fi

Download one file first and build with it. Use a small area and a short date range. Fetch larger files before you arrive.

4. Before you leave home

1. Download the files your demo needs.
2. Record a short screen capture of your demo, in case the network fails.
3. Bookmark your challenge page on this site.