Proposal of New Triggered Lightning Launch Commit Criteria for Japan's rocket launch

Triggered lightning for rocket launch cause the fail. In fact, Atlas rocket of 1987 failed by the triggered lightining. About the triggered lightining, the threshold of electric field totake insulation breakdown is lower than natural lightning to increase the field with the flying rocket. But the level to increase is difficult to decide and there is 3kV/m as safety level of E-field threshold, which is discussed in NASA.

In addition, to define the launch commit criteria, the correlation between 3kV/m and remote sensing parameter (ex: Thickness of cloud, ground E-field, Radar). So, NASA took many research and revise the criteria with professionals of atomosphic electricity, which are Radar, Airborn filed mill and ground base field mill network.

But JAXA don't have enough in-cloud data of our rocket range to revise. Modern main criteria to slip the launch opportunity is the thickness of cloud 1.8km with 0~-20degree Celsius. It have caused over half of our rocket launch. But we looked some case, when we thank no lightning risk.

So, we started the research of Triggered Lightning Launch Commit Criteria, last year. In this presentation, we explain the overall activity with the RAIJIN campain in this Feb, which are airborn field mill, X-band dual poralization radar, ground based field mill and Videosonde.. Also, propose the new criteria.