SCoPEx Statements

SCoPEx was cancelled in March 2024. Click here for more information.

March 31, 2021

Update from the SCoPEx Advisory Committee

The SCoPEx research team fully supports the Advisory Committee’s recommendation that any equipment test flights in Sweden need to be suspended until the committee can make a final recommendation about those flights based on robust public engagement in Sweden that is broadly inclusive of indigenous populations. Our research team intends to listen closely to this public engagement process to inform the experiment moving forward. We also appreciate the close technical collaboration with the Swedish Space Corporation (SSC) and the thoughtful way SSC has approached this topic.

December 15, 2020

Press Release

The SCoPEx research team has asked the independent SCoPEx Advisory Committee to review our plans for a proposed platform test in Sweden in June 2021. This test would not be the experiment itself, but rather a test of the SCoPEx platform without the release of any particles. 

This balloon flight would be managed by Swedish Space Corporation (SSC), flying out of Esrange Space Center in Kiruna, Sweden. As mentioned, the goal of this flight is to test the SCoPEx platform. Specifically, we would like to test the gondola’s horizontal and vertical control using the winch system and propellers as well as the power, data, navigation, and communication systems. We would not release any aerosols, nor fly an aerosol injection/release system. Still, we will not proceed with this flight without a formal recommendation authorizing the flight from the Advisory Committee to Harvard management. We have asked the Advisory Committee if they can complete their review and reach a decision—be it positive or negative—about this platform test by February 15, 2021, of course, contingent on the experiment team providing them with timely access to materials needed for the review. (As a reminder, the independent Advisory Committee was established to provide advice on the research and governance of SCoPEx. They have already begun to carry out important work. For more information about the Advisory Committee, please visit their website or contact Sally Klimp (

A platform test is needed before the science experiment because SCoPEx will use a new flight platform that has not flown before. In other words, there are significant technical challenges in developing it as an operational vehicle independent of the challenges of the actual solar geoengineering experiment. For example, only a few propelled balloon systems have flown in the stratosphere to date. Balloon operators have told us about a few other simple gondolas with propellers that are analogous to SCoPEx, but we do not have access to the details of those systems. We therefore need to test the new platform and concept of operations before conducting the science flight so we can examine its novel capabilities, e.g., verify its operation, controls, and communications. Yet, this platform will not carry systems for releasing particles.

The timing of the science flights will be contingent on the results from this proposed platform test. It’s possible that we will need additional platform flights if we do not resolve sufficient engineering issues on this flight, which might occur if we have a major equipment or concept of operations failure. The timing of the science flights will also depend, of course, on the Advisory Committee’s review and authorization and on other relevant regulatory bodies. Additionally, the location of the science flights is undetermined at this time because it will depend on the evolving balloon launch industry, scientific objectives, and input from the Advisory Committee and other stakeholders.

Because this is not the science flight, it is a rather standard stratospheric balloon flight when viewed in the context of other balloon flights. In 2019, for example, estimates suggest there were more than 300 stratospheric balloon flights over the course of the year. This platform test is interesting to us as engineers and scientists because we are hoping it will provide information about our equipment for the science flight, but stratospheric balloons are flown regularly, from Google’s Loon program, which launched at least 35 balloons this year as it seeks to build a new layer of connectivity technology in the stratosphere to expand internet access worldwide, to NASA’s scientific ballooning work, which usually launches 10 or more balloons each year as it carries out scientific and technological investigations, including fundamental scientific discoveries that contribute to our understanding of the Earth, the solar system, and the universe. Swedish Space Corporation, for example, has flown balloons in partnership with NASA, CNES (the French space agency), and STRATOS (the Canadian space agency balloon program).

We have chosen to partner with Swedish Space Corporation and fly in Sweden because of their availability for summer 2021, promising flight trajectories, and significant experience launching scientific balloons. We also looked at several US balloon operators, but because of COVID-19 and other logistical and scheduling challenges, there were no US based options that could provide a 2021 early-summer launch with a landing on land, and that had already secured launch equipment. (Landing on land is important because we need to recover and reuse our platform equipment. And launch equipment, such as a crane or bucket loader and balloon spool, is needed to safely get the payload off the ground. Indeed, US based Raven Aerostar had to cancel our prior agreement many months ago because they could no longer obtain launch services, as we noted on our website at the time.) 

We also needed to make sure we identified a partner who could successfully manage the needs of the SCoPEx balloon, as flight safety is of utmost importance to us. The experimental design for future SCoPEx science flights requires a balloon that will fly a 600 kg payload near an altitude of 20 km. This is a lower altitude than many other stratospheric balloon missions, and launch equipment for this weight class and balloon size is not readily available. We also required that the launch site have relatively low winds, the ability to fly a 4-6 hour flight, and the capability to land on land, as noted above. Swedish Space Corporation performed a trajectory analysis based on wind data from 2018 and 2019 and showed favorable trajectories with suitable landings for the entire summer season (April 15-September 15). For example, these projected landings are in extremely low population areas, which is important from a flight safety perspective. 

Swedish Space Corporation is a global provider of advanced space services and has been launching scientific balloons for over 40 years. They have been launching balloons out of Esrange Space Center in Kiruna, Sweden since 1974 and they have also provided launches from outside Esrange since 2018. They will be an exceptional partner for SCoPEx. And we hope that the significant partnerships between Swedish Space Corporations and various US balloon operations could lead to enhanced international collaboration and future launches both from Esrange and within the US. Moreover, and perhaps most importantly, working in Sweden will enable us to increase international scientific collaboration around the SCoPEx experiment, which is critical to us. We have already begun to reach out to Swedish scientists, and we are in discussion with German scientists who have now expressed some interest in collaborating on this flight. We are looking forward to forming new partnerships that will enhance the diversity of perspectives studying SCoPEx and improve the science.

August 3, 2020

Statement from Frank Keutsch, Principal Investigator of SCoPEx and Stonington Professor of Engineering and Atmospheric Science, Harvard John A. Paulson School of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology and Department of Earth and Planetary Sciences:

"We understand that there are complex societal and governance issues surrounding solar geoengineering and SCoPEx. It's why we have taken extraordinary steps to try to perform the experiment in a manner that exemplifies good governance, implementing an unprecedented level of transparency and recruiting a highly qualified, independent, external committee to provide advice that we have and will continue to take very seriously.

We all realize this is a great learning process, so we and the Committee are doing everything possible to make sure there are opportunities for people to provide comments and constructive criticism. Such input will help the Committee be in the best position possible to weigh whether or not we should proceed with the experiment. We therefore encourage you to provide feedback on their proposed Societal Engagement Process.

I want to thank the SCoPEx Advisory Committee for all of their work thus far. It's exciting to see their new Societal Engagement Process released.

I am also incredibly thankful for the time, energy, wisdom, and dedication that Dr. Louise Bedsworth volunteered as Chair of the SCoPEx Advisory Committee. She has played an invaluable role in our governance process and has helped advance critical pieces of work. Their newly proposed Societal Engagement Process is one recent example, and I very much appreciate their advice on this front. The governance of SCoPEx has always been as central as the science, and we are very fortunate to have had Dr. Bedsworth's leadership and thoughtful approach in this process. I look forward to our continuing work with the Committee, and I sincerely thank all of the members for their important engagement."

Statement from Rick McCullough, Harvard Vice Provost for Research:

"I would like to sincerely thank Louise Bedsworth for leading the SCoPEx Advisory Committee. From the beginning, I have appreciated her thoughtfulness and unwavering commitment as she has worked to develop a governance process that will not only be valuable to SCoPEx, but will also be a model for others. We are grateful for her service, and are excited about the foundation that she and the Committee have already helped build. I look forward to our continuing work with the Committee, and I sincerely thank all of the members for their important engagement."