Isar outlines what caused the failure on the first launch of its Spectrum rocket

Spectrum falling seconds after launch
According to officials of the German rocket startup Isar Aerospace, its Spectrum rocket failed during its first launch in March 2025 because of a loss of attitude control, which then caused the rocket to self-destruct.
Alexandre Dalloneau, vice president of mission and launch operations at Isar, said that the company had not properly characterized bending modes of the vehicle at liftoff. “The controllability has to be tuned in order to counter such behavior,” he said. That environment was not fully modeled and incorporated into the vehicle’s control system. “We were outside the environment that we expected, so that the controllability does not succeed.”
That loss of attitude control caused the vehicle to go outside the safety zone at the launch site. That, in turn, triggered the flight termination system on the rocket. He said the company has revised its modeling of vehicle modes at liftoff to correct the problem.
The company is now working towards a second launch from Norway’s Andoya spaceport, which it hopes to attempt either late this year or early next year. Afterward it hopes to launch eight-plus times a year, based on the demand it is presently seeing for its rocket.
Spectrum falling seconds after launch
According to officials of the German rocket startup Isar Aerospace, its Spectrum rocket failed during its first launch in March 2025 because of a loss of attitude control, which then caused the rocket to self-destruct.
Alexandre Dalloneau, vice president of mission and launch operations at Isar, said that the company had not properly characterized bending modes of the vehicle at liftoff. “The controllability has to be tuned in order to counter such behavior,” he said. That environment was not fully modeled and incorporated into the vehicle’s control system. “We were outside the environment that we expected, so that the controllability does not succeed.”
That loss of attitude control caused the vehicle to go outside the safety zone at the launch site. That, in turn, triggered the flight termination system on the rocket. He said the company has revised its modeling of vehicle modes at liftoff to correct the problem.
The company is now working towards a second launch from Norway’s Andoya spaceport, which it hopes to attempt either late this year or early next year. Afterward it hopes to launch eight-plus times a year, based on the demand it is presently seeing for its rocket.