The thermal control approach of the Solar Orbiter ESA (European Space Agency) Spacecraft is based on the use of a heatshield to protect the platform from the extreme 14 Solar Constants exposure at 0.28 Astronomical Unit from the Sun. However, some subsystems like the High Gain Antenna cannot be accommodated fully behind the Heatshield. It was originally planned to use the BepiColombo High Temperature Multi Layer Insulation technology for Solar Orbiter needs but some stringent cleanliness and electromagnetic requirements have forced the development of a new thermal protection system able to guarantee the antenna performance at temperatures up to 600°C. This paper details the stages of the development of the TPS from scratch until Proto Flight Model manufacturing. All environmental aspects of the project are considered and discussed: First, the Design and analysis phase including the first requirements identification and thermal performance benchmark. Several lay-ups considering aluminium and titanium layers have been studied and their insulation performance modelled and estimated. Then, a Breadboarding phase including thermal testing at high temperature and vibration testing at qualification levels has been performed. The lessons learned from this hardware testing phase have been used to optimize the design in terms of cleanliness and contamination control, thermo-mechanical behavior and accommodation. The final TPS design considers an ensemble of bended thin titanium sheets, coated with Astroblack coating, supported by flexible standoffs compensating thermo-elastic deformations on the Antenna support structure to guarantee the RF performance. The constraints of the Assembly, Integration and Testing on the Manufacturing including bending and coating technology are described as well in this paper. The reader will consequently follow the full development of a new original thermal protection system and face the complexity of the different environmental constraints of such a high temperature challenging science mission at the edge of the technology.