Launcher Antenna Discharge Test

To keep a launcher connected to the ground during flight is an incredibly challenging task for an antenna. Dealing with high temperatures, vibrations, and atmospheric slipstream is difficult enough, but adding shifting atmospheric pressure levels as the launcher enters the vacuum of space (and potentially returns) can pose a risk of dangerous electrical discharges known as corona. These discharges are being tested for in the image above, provided by Anteral.

The antenna design being tested at ESA’s High Power Radio Frequency Laboratory in Valencia, Spain is one of four that will be used on Spain’s Miura 1 sub-orbital micro-launcher, which was developed by the PLD Space company. However, these four antennas are also undergoing a separate test campaign to qualify them for future use in broader applications.

“There are four different types of antennas in total, each flown in pairs aboard Miura 1,” explains Victoria Iza, an ESA antenna engineer.

“One is a Global Navigation Satellite Signal antenna, used to track the position of the launcher. Another is an S-band antenna that transmits telemetry. Additionally, there are C-band and UHF antennas that serve the security system, which ensures a safe ending to the flight in case of malfunction. These antennas operate redundantly.”

Manufactured by Spain’s Anteral company, this quartet of conformal dielectric antennas, roughly the size of smartphones and designed to fit around the upper stage hull, has already been qualified as part of the avionics bay of the Miura 1. However, with the increasing number of European small launchers and the support provided by ESA’s Boost! program, these antennas have the potential for wider applications. Therefore, they are undergoing a separate qualification program.

Currently, the antennas are undergoing environmental testing, including thermal vacuum and vibration tests. These tests are essential as the antennas must withstand harsh thermomechanical conditions during launch, orbital flight, and eventual return to Earth.

To ensure the antennas’ robustness and functionality, the team used a combination of computer simulations and on-ground test facilities such as electro-magnetic shakers, pyro-shock tables, and thermal-vacuum chambers.

Corona discharge testing was performed at ESA’s High Power Radio Frequency Lab. When a radio frequency antenna is surrounded by a small amount of atmosphere, such as when a launcher enters or exits a planetary atmosphere, there is a potential risk of ionization and damaging discharge. The antennas were placed in a glass container, allowing for changes in the surrounding air levels while the antennas remain operational.

The antenna development project is crucial for Anteral’s positioning in the small launcher market. The support from ESA has enabled Anteral to fully qualify the antennas that will be used on Miura-1 and potentially on many other launchers and varied applications where reliability is essential.