Balloons Blog

SSI 52 Breaks World Record (Again)

On May 22nd, 2017, at about 9:00AM, we launched our two-time world record breaking, self-equilibrating latex balloon payload, called ValBal (since it uses a valve to vent helium gas to reduce lift, and drops ballast to reduce mass and rise).
SSI-52 Mission Patch
SSI-52 was our first launch of the spring quarter and our first test of a new generation of avionics, as well as a test of a new polycarbonate mechanical structure.

Though launches usually take multiple hours, we streamlined our operational procedures for this launch so well that we launched only 40 minutes after arriving on site at Brigantino Park, in Hollister, CA.  SSI-52 smoothly equilibrated at about 15 km, even higher than commercial airlines flight paths, and floated east as we all sat on the edges of our seats.
Balloon Team Co-lead Davy Ragland with ValBal Prior to Launch
We monitored ValBal over the course of several sleepless nights and cheered it on as it struggled through a rough storm in North Carolina. Eventually, it passed the point of no return and flew out over the Atlantic Ocean, becoming our second balloon payload ever to do so.

After just over 79 hours of flight, ValBal again broke the world record for the longest duration flight by a latex balloon.

As the days dragged on, ValBal began to run low on both power and ballast capacity, but neither of those ultimately ended the mission. After 3 days, 16 hours, and 40 minutes of flight, the balloon popped and ValBal proceeded to fall under the parachute for the descent, finally landing in the Atlantic Ocean half an hour later off the coast of Western Sahara. SSI-52 Flight Path

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SSI 47 Breaks World Record

On November 5th, 2016 Stanford Student Space Initiative's Balloons Team launched a High Altitude Balloon named ValBal, short for "Valve-Ballast" - a novel platform that utilizes a gas venting valve and a ballast dispenser to zero its ascent rate and maintain a nearly constant altitude.  Conceived in the winter of 2014, ValBal has been in development and testing for over a year and a half.  This November, ValBal broke the world record for the longest duration flight of a latex balloon, flying from Modesto, CA to the outskirts of Quebec City, Canada.
This flight of more than 79 hours adds almost 10 hours to the previous world record, also set by SSI with an earlier version of ValBal in June of 2016. The ValBal platform is capable of autonomous and dynamic altitude control, a significant improvement over the passive control employed by the previous record holders. This capability allows ValBal to carry kilogram-scale research payloads for extended periods in the upper atmosphere, which SSI hopes to begin flying next year. The team will be presenting their work at the 2017 IEEE Aerospace Conference in March, 2017.
A video detailing this launch can be found at

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Balloons 2016 Year in Review

9 Launches.
19 Balloons.
Countless hours of work sessions and launch prep.
1 World Record.

It’s been an exciting second year for the Balloons team.

We kicked off the beginning of fall quarter with new member onboarding launches. New members were split up into teams and given a variety of goals to aim for: some pertaining to ballooning basics, and other that the balloons team has yet to accomplish, yielding payloads that had a wide range of capabilities.

Onboarding launch: SSI-23, SSI-24, and SSI 25 prepare for launch!

The fast-paced, rudimentary projects allowed new members to gain valuable hands-on experience with the basics of high altitude ballooning, from avionics, to payload construction, to launch procedures.

Moving forward, the team focused on data collection and testing that would aid us in improving flight duration. One project group took on the issue of UV degradation of latex. The data we gathered allowed us to better characterize UV-A and UV-B dispersion by altitude, and some further steps were taken investigating the plausibility and effectiveness of coatings that would absorb and reflect UV light. Another group took on development of a solar-tracking apparatus that would reorient a solar panel array to face the direction of strongest sunlight and thus generate more consistent photocurrent.

Shortly after, we became intrigued with the idea of a modular payload platform – a way to standardize the balloon payload in a way that would facilitate launch prep and be advantageous down the line when flying research payloads.

Integral to the realization of this goal was Project SPACE: a project created last year dedicated to the mechanical modularization of the balloon payload. Inspired by last year’s Project SPACE Tesseract, we created HABHIVE. As a modular payload platform, HABHIVE is designed to expedite the payload construction process and facilitate the launching of new projects, including sensor packages, cameras, and so forth, with minimized mechanical production necessary prior to launches. The platform features interchangeable, customized walls that are switched out based upon the needs of different projects.

Equally as important to the modular payload is the electrical design. That being said, the development of customized avionics has also made tremendous strides this year. Our unique PCB design is a highly flexible, feature-rich platform for standard profile high altitude balloon flights. It is responsible for all the basic functionalities of a balloon payload, including thermal regulation, data-logging, and—in the near future—RF communications. The HABHIVE team and the avionics development division often work together and have cross membership to ensure a seamless integration between the two parts to create a unified whole.

SSI-39 – the first flight of HABHIVE V2 and standardized avionics PCB
Conceived in the winter of 2014, ValBal has been in development and testing for over a year and a half. ValBal, short for "Valve-Ballast" is a novel platform that utilizes a gas venting valve and a ballast dispenser to stabilize altitude. The payload was recently awarded first place in the “Best Design” category of the Global Space Balloon Challenge. Shortly thereafter, ValBal Mk5.1 flew for a distance of over 3,500 miles, spanning the entire North American continent, for over 70 hours, breaking a world record for longest duration flight of a latex balloon! You can read more about the record breaking flight here.

Lastly, our web-based mission control suite, habmc, through launch-to-launch development and iteration, has proven an outstanding asset to the team. The suite handles satellite communications, provides data visualization, and illustrates restricted airspaces to name just a few of its capabilities. Through habmc, all of SSI and hundreds of other on-lookers can track payloads during flights. Stay tuned and visit to track our future launches in the upcoming year!

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SSI-41 Crosses Continental US & Breaks World Record

SSI is always proud to showcase our team's launches.

Today, we're especially proud of SSI-41.

SSI-41 is the flight of ValBal Mk 5.1, a slight revision to the ValBal Mk 5 vehicle flown just over a month ago. The Mk 5 vehicle, an enormous improvement over Mk 4, managed to fly its way to Mexico over the course of a 16 hour journey, and landed due to power anomalies.

The response to the power anomalies and other imperfections in the Mk 5 vehicle came in the form of Mk 5.1 — a vehicle that would fly for a distance of over 3,500 miles, spanning the entire North American continent, for over 70 hours, to bravely adventure where no latex high altitude balloon has ever gone before.


ValBal, short for "Valve-Ballast" is a novel platform developed by the SSI Balloons team that utilizes a gas venting valve and a ballast dispenser to zero its ascent rate and maintain a nearly constant altitude. Conceived in the winter of 2014, ValBal has been in development and testing for over a year and a half. ValBal first equilibrated at altitude in SSI-18, traversed state lines in SSI-21, flew to Canada in SSI-22, and landed in Mexico in SSI-38. 

The motivation for the development of such a platform is simple. In the realm of high-altitude ballooning, latex balloons are by far the most affordable, starting at tens of dollars and costing at most a few hundred dollars. However, latex balloons, by their very nature, are designed for short term flights -- most often, to fly a payload to near-space altitudes, followed by the burst and descent of the balloon. This class of flight typically lasts no more than three hours and travels less than 100 miles. By contrast, more expensive balloon technology, such as Zero Pressure and Super Pressure balloons, are capable of flying for long durations of time, but at the cost of thousands to millions of dollars per flight. Thus, ValBal was developed to provide research payloads with affordable access to long-duration flights in a near-space environment.

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The Launch

SSI-41 was scheduled for launch on the evening of Tuesday, June 14th. The team arrived at the launch site (Laird Park, near Modesto CA) at approximately 9:45 PM PDT. After setting up all of the necessary equipment, the team began the process of vehicle pre-flight verification. After preliminary testing of vehicle sub-systems, including valve, ballast, and flight controls, the system passed pre-flight verification. The team spent considerable time verifying satellite communications -- a crucial vehicle system. Satellite communications allow the team to receive data from the payload over the Iridium satellite constellation, and also uplink commands to the payload for altitude controller adjustments, power distribution management, and other performance alterations.

After unfortunately long delays in communications intervals, the vehicle was cleared for launch. The team began filling of the 1500g Kaymont Latex balloon, and, once filled, attached the ValBal Mk 5.1 vehicle to the neck of the balloon and filled the payload with ballast. The payload was finally released at 4:18 AM PDT, June 15th.

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The Flight

Upon release, the payload registered a nearly 5 m/s ascent rate. The first step in flight is a successful equilibration at altitude, making the initial ascent of the vehicle one of the most crucial windows of the mission. As several lifting-gas releases were reported over satellite communications, the payload continuously decreased its ascent rate, equilibrating at 6:37 AM PDT at approximately 12,500 m. 

ValBal operates around a designated setpoint altitude. About this altitude, it is allowed to oscillate within specified flight ceiling and floor bounds. As it approaches either the ceiling or the floor, it is incentivized to either vent gas or dispense ballast to compensate its rate of ascent and return to setpoint altitude. Although the system actively controls the valve and ballast sub-systems to maintain altitude, there are in fact long periods of inactivity when the system is able to reach nearly neutral buoyancy. During SSI-41, ValBal experienced extremely long windows of system stability, not needing to vent or ballast significantly to maintain altitude. 

The payload continued a nominal flight, beginning with a north-east heading and flying through Nevada, Idaho, Wyoming, and Montana before entering Canadian airspace at 6:23 PM PDT on June 16th. The payload continued its flight through the Saskatchewan, Manitoba, Ontario, and Quebec provinces until a return to United States airspace at 1:21 PM PDT on June 17th. At this point, the payload had surpassed 57 hours and 2 minutes aloft, the previous world record for latex balloon fight time, set by the California Near Space Project's CNSP-11 launch. ValBal flew over 3,000 miles and continued on a south-east trajectory through New York state, crossing the continental United States.
At 2:28 AM PDT, June 18th, the payload landed in the northern Atlantic Ocean. It flew for a final total distance of 3565 miles, setting a new latex balloon record flight time of 70 hours, 10 minutes.
Altitude Over Time

Custom Built Hardware

All iterations of ValBal have been built around custom-made avionics and mechanical systems. The v5.1 avionics suite consists of two printed circuit boards, a battery pack and main flight computer, designed by SSI team members using Altium Designer, which was graciously provided to SSI by our platinum-tier sponsor, Altium Ltd. The balloon's mechanical systems consist primarily of a laser cut acrylic structure, with the avionics, batteries, and recovery GPS housed in a styrofoam enclosure further insulated with fiberglass-aerogel composite. The valve and ballaster are actuated by two external motors, which SSI modified and qualified for cold operation.
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Mission Control Suite (HABMC)

The flight of SSI-41 would have been tremendously harder to visualize and control without the aid of habmc, an SSI-internal mission control suite developed by SSI Balloons team member Kai Marshland. habmc processes all satellite communication data, handles parsing, data visualization, mapping, airspace and weather overlays, and tremendously more. The suite is new in 2015 and has allowed all of SSI and hundreds of on-lookers to track the payload during its flight. For those interested in tracking the payload as it flies, as well as tracking future payloads, visit
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The flight of SSI-41 is an exemplary case of the capabilities of the ValBal system for long duration missions. The entire system comes at a low cost of only hundreds of dollars for the mechanics, electronics, and flight balloon. By comparison, zero pressure balloons typically cost no less than $1,000 and do not include avionics, power, communications, or gas. ValBal is also significantly more capable than a zero pressure balloon, as it can equilibrate at virtually any altitude between 10 and 25km as required by an onboard experiment or to catch favorable winds. The vehicle can fly for multiple days continuously at a specified altitude, collecting data over time.

In the future, the ValBal vehicle will continue to be pushed for increasing levels of endurance, and be more readily equipped to carry research payloads in an on-board payload bay. Targetting payload masses on the order of 1 kg, the team has envisioned atmospheric research, weather tracking, near-space biological experiments, and other payloads, and is interested in collaborating with researchers seeking to conduct high altitude studies.

An additional future goal of the team, as a display of system capability, is to fly ValBal in a journey to circumnavigate the planet, launching from California and recovering on the western coast of North America. 

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