Flight W-2162: The Odyssey of a WindBorne Global Sounding Balloon

Introduction

On January 18, 2025, one of WindBorne’s AI-enabled, long-duration Global Sounding Balloons (GSBs), launched from Palo Alto, California and embarked on an extraordinary journey, including a near circumnavigation around the globe. Although this was not the first time one of our GSBs has traveled around the world, this flight was particularly notable: before landing, the balloon successfully deployed a dropsonde. This made Flight W-2162 one of our first standard operation flights to do so, and marked a significant step forward in increasing the capabilities of our global GSB constellation.

At WindBorne, we are reshaping the future of atmospheric sensing. Currently, there exists a devastating gap in critical in-situ weather observations—merely 15% of the world is adequately observed for weather forecasting, according to the Weather Meteorological Organization (WMO). Traditional weather balloons cannot close this gap, as they are limited by their stagnant navigation and short lifespans, during which they can only collect data over a brief, single vertical path. These limitations have created “data deserts” over crucial regions, including over oceans and in remote places, whose in-situ observations are key to improving weather forecasting.

At the nexus of WindBorne’s mission to close this gap is Atlas: the world’s first, only, and largest constellation of concurrently aloft weather balloons. At full scale, Atlas will comprise 10,000 GSBs, providing unprecedented and persistent in-situ atmospheric insights, including pressure, temperature, humidity, wind speed and direction.

What is a Dropsonde?

Dropsondes are in-situ measurement packages designed to capture atmospheric data in storm systems, including tropical cyclones or hurricanes. Traditionally, dropsondes require a dedicated aircraft to deploy them directly over their target storm system—a costly and dangerous endeavor.

With partial funding from NOAA’s Weather Program Offie (WPO), the Research & Development (R&D) team at WindBorne is developing dropsondes for use in our global atmospheric sensing constellation. Each dropsonde attaches easily to a “host” GSB unit and is outfitted with sensors to collect wind speed, temperature, humidity, and geopotential height.

Why Dropsondes?

Given that WindBorne’s GSBs already provide the capability to capture in-situ atmospheric soundings anywhere in the world, why invest in dropsonde capabilities?  Well, some of the most impactful atmospheric data for forecasting occurs around different weather phenomena—think atmospheric rivers, hurricanes, and severe weather.

The downside? These storm systems are volatile, bringing turbulent winds, potentially extreme temperatures, and heavy precipitation. Collecting data in such harsh conditions are costly and potentially dangerous to human life via traditional methods—and while our GSBs are quite resilient to a broad range of temperatures and conditions (our sensors are custom calibrated to withstand temperatures as low as -80C), even they prefer to stay out of extreme storms. The ability to release a dropsonde from a GSB that passes above a storm system enables us to gather this valuable data at a fraction of the cost, and with no risk to human life.

Prior R&D flights and our operational work with Hurricane Milton proved dropsondes could provide this capability. At the time, however, these flights required dedicated navigation, radio hardware R&D, and temporary launch sites.

We’ve now developed this integral technology to the point that it’s ready to come out of R&D and into our standard operation pipeline.

The Global Journey of Flight W-2162

Currently, WindBorne has seven permanent launch locations, including at our headquarters in Palo Alto, CA. From here, we launch our GSBs equipped with operational  dropsondes—and on January 17, 2025 at 3:51 PM PST, Flight W-2162 began its mission. The directive? Collect as many soundings as possible…and deploy a dropsonde over the data scarce Pacific.

Utilizing WindBorne’s proprietary ground and on-board flight navigation system, W-2162 flew over the United States, passed a chilly journey over the North Atlantic, warmed up above the Mediterranean, and coasted along the Asian continent before reaching the North Pacific Ocean, well on its way to a circumnavigation. By relying on a suite of dynamic forecasts, including Windborne’s own WeatherMesh forecasts, our GSB safely avoided tempestuous weather while maximizing soundings collected around the globe.

Time to Drop!

10 days after launch, GSB W-2162 had reached the edge of a system over the eastern Pacific Ocean. This system was brewing with the potential to contribute to a major atmospheric river across the Pacific.  Atmospheric rivers are a phenomenon whereby concentrated moisture moves in a relatively narrow band across the atmosphere. With the term coined in the 90s, only relatively recently have scientists conducted deep studies to better understand these systems. The Scripps Institute of Oceanography at the University of San Diego is one such institution, and conducts yearly studies, which WindBorne now supports with in-situ data from our GSBs.

Flight W-2161 was in an excellent position to gather valuable data about this system via dropsonde.  Our Mission Control Center greenlit dropsonde release—and with a few commands sent via satellite link, the GSB released its dropsonde payload:

This dropsonde collected readings of wind speed, temperature, humidity, and geopotential height all the way down to 30 m above sea level, relaying data back to W-2162 via radio link. W-2162 then beamed the data to our ground-side servers via satellite link, completing the data acquisition cycle in minutes.

With W-2162’s payload successfully deployed and data successfully retrieved, our GSB continued on its way, continuing to collect soundings across the Pacific Ocean until it completed its mission. Thirteen days after it first launched out of Palo Alto, W-2162 had traveled 480 km of vertical distance, collected 55 atmospheric soundings, successfully deployed a dropsonde, and nearly completed circumnavigation around the globe.

During that time, the system over which W-2162 deployed its dropsonde became part of a large atmospheric river that would drench the California coastline the first week of February.

Onwards and Upwards

Where do we go from here? Flight W-2162 proved GSBs can incorporate dropsondes successfully as part of normal mission execution. This gives WindBorne the incredible capability to monitor extreme and interesting weather systems across the globe.

Here at Windborne, we are continuing to quickly scale up our GSB constellation to reach full Atlas scale (10,000 balloons).  At Atlas’ full scale nearby GSBs can deploy or reroute quickly to sample atmospheric conditions around and within these systems as they occur. In this way, future GSBs equipped with dropsondes like W-2162 will close the global in-situ data gap and push us further towards decoding the workings of our planet’s nervous system.