The aim is to slow down the growth of space debris
On June 23, 2022, the Long March-2D Y-64 carrier rocket was successfully launched from Xichang SLC. On June 26, the de-orbit sail on the Long March 2D payload module was successfully deployed in orbit, and the telemetry signal was normal. With the piloting of this “big kite”, the launch vehicle's payload module, which weighs about 300 kg, will re-enter the atmosphere within 2 years, releasing valuable orbital resources.
This mission is equipped with a very large area off-orbit sail, a more complex structure, and more advanced technology.
The sail surface is extremely thin, less than one-tenth of the diameter of a hair, and through precise folding design and high-density compression, the sail surface can be stowed into a very small volume, and with the advanced elastic unfolding mechanism, the sail surface area in the fully unfolded state reaches 25 m².
This lightweight and high spread ratio allow the de-orbiting sail to be retrofitted to various mature spacecraft without taking up the platform's own envelope.
This is the largest off-orbit sail product in China at present, and it is also the first time in the world that off-orbit sail is applied to the cabin of a launch vehicle, aiming to slow down the growth of space debris.
In February 2021, the first international standard ISO20893 “Space Systems – Space Debris Mitigation for Launch Vehicle Orbital Stages” was developed under the leadership of the 8th Academy. Detailed Requirements for Space Debris Mitigation of Launch Vehicle Orbital Stages were officially released, becoming the first aerospace international standard developed by China and approved in the 14th Five-Year Plan.
This mission is a breakthrough attempt to further develop new markets and generate new benefits by realizing mature products with new technologies.
With the mature application of the tandem configuration of the Long March-2D rocket, the payload module, as the “exclusive room” of the satellite, will stay in orbit for a long time after separation into orbit, becoming a high priority for the rocket designers.
To this end, the overall design team of the Long March-2D Model gave full play to the advantages of the 8th Institute in several fields and innovative proposed a general scheme of "upper stage sub-stage application system + large area deorbiting sail" for the accelerated de-orbiting and long-term status monitoring of the launch vehicle payload bay.
In other words, the successful practice of accelerating satellite de-orbiting with the help of de-orbiting sails is applied to the rocket payload module, i.e., “satellite capsule”, so that it will not continue to wander.
Making a satellite's entrance graceful
A de-orbiting sail is a film structure on a satellite (or spacecraft) that can be deployed in space autonomously. In simple terms, it acts as a "kite" in space, allowing the satellite to gradually slow down in orbit by increasing its windward area.
When the satellite is launched into orbit, the de-orbiting sail is stowed, and at the end of the satellite's life, the sail unlocking command is activated, and the film sail is unfolded.
Without de-orbiting measures, the satellite will occupy orbit for 12 decades or more at the end of its life; with a 2m² de-orbiting sail, the time in orbit can be reduced to less than 10 years.
It is worth mentioning that the use of thin-film to implement de-orbiting, no fuel consumption, even in the case of spacecraft failure out of control, only a small amount of current to achieve the film sail deployment, effectively solves the need for de-orbiting out of control spacecraft.
As one of the frontier technologies in today's international space field, the space ultralight thin-film expandable structure technology is a powerful practice of the Space Structure and Mechanism Technology Laboratory, which has been working deeply for more than ten years to realize the transformation from pre-research results to engineering applications.
As early as September 2019, the Space Structure and Mechanism Technology Laboratory (SSMTL) jointly developed China's first case of standard off-orbit sail for micro-nano-satellites, "Taurus", with EYES. At that time, the sail deployment area was only 2.25m², but it achieved a remarkable de-orbiting effect; later, it was used for "Qilu 4", "Foshan 1", "Tianshu 1" and "Jinzhu 1". "Golden Bauhinia II" and many other commercial satellites have been equipped with de-orbiting sails to realize the application of thin-film system.
In this mission, the model development team further broke through a number of key technologies on the basis of "Taurus" deorbiting sail, and achieved a technical leap of more than ten times in the area of deorbiting sail deployment, which filled the gap with increasing resistance to the deorbiting capability of domestic medium and large spacecraft and launch vehicle entry module.