Speaker
Description
Development of generic MLI flap for spacecraft interface ring
The launch vehicle adapter (LVA) is used to connect spacecraft to the launch vehicle. The spacecraft interface ring, which connects the S/C to the LVA, remains exposed after separation, when the spacecraft is released to its target orbit. The unprotected and exposed interface ring on the spacecraft represents thus a significant heat sink, depending on the orientation of the spacecraft. Additionally, this ring often has restrictive temperature limits, requiring heaters and/or careful orientation of the spacecraft in order to remain within these defined ranges. Unfortunately, due to the mechanical requirements of the LVA, coatings, in order to improve the thermo-optical properties, usually represent only a very limited option.
The goal of the ESA project “Development of generic MLI flap for spacecraft interface ring” is to overcome these challenges by developing a system that can cover the interface ring after spacecraft separation. Apart from covering the I/F ring with insulation, the main goals of the design are to be simple, passive, and scalable to different LVA ring diameters.
The design was also focusing on easy and late implementation of the flap system as well as minimum volume consumption to generate the least impact on S/C design. Different solutions were investigated over the course of the project, and a trade-off was done, ranking the options regarding their viability. In the end, a system mounted on the inside of the S/C interface ring was selected, with individual, pre-tensioned flaps which are retracted initially to not disturb spacecraft mating operations and launch. During separation, these flaps close passively and guided in alternating sequence once the spacecraft is separated. The flaps are equipped with MLI, which forms closed overlaps in the final position, offering a significant improvement in thermal performance when compared to the bare exposed I/F ring. The type of insulation needed can be adapted for a wide temperature and performance range allowing the MLI flap to be used for practically every spacecraft, if seen needed.
According to the design, a representative segment of the system has been built and tested regarding mechanical functionality, MLI coverage of the S/C I/F ring, compatibility with launch as well as shock loads and influence of thermal cycling on the system.
The selected design and current state of the testing campaign will be subject of this talk.
