ZBO:
ZBO:
Development of a cryogenic propellant depot
CNES R&D Challenge
CNES R&D Challenge
Over the past year, Absolut System has been working on the development of a cryogenic propellant depot, as part of the CNES R&D Challenge for the reuse of the upper stage.
The use of depots and on-orbit refueling are essential for long-term lunar and Mars missions, as they enable multiple launch missions and reusable tugs in space. The use of smaller depots and refueling missions targeting more specific orbits could also help improve the sustainability of space operations.
The objective: to design a system capable of storing and transferring cryogenic propellants in orbit, with a view to being launched (filled) as a payload on a possible evolution of the Ariane launcher.
This development included an in-depth analysis of mission scenarios. Our cryogenic expertise was used for thermal modeling to optimize the ZBO (zero-boil off) system and to model the cryogenic propellant transfer process in microgravity.
Cryogenic innovations have long been essential to the space industry for a variety of applications: imaging, propulsion, etc.
For missions in a geostationary orbit, following a rendezvous in a geostationary transfer orbit (GTO), the launcher can deliver cryogenic propellants to a reusable fuel tug, which will then transport them to GEO to refuel satellites.
The system has been designed for two configurations: LOX/LCH4 and LAr. These were chosen for their compatibility with future Mars missions and their likelihood of use in future systems. However, these cryogenic propellants present several additional challenges which Absolut System will address in further studies:
- The tanks will require a combination of passive insulation and active cooling using a Turbo-Brayton cryocooler, to achieve long-term ZBO storage.
- To be able to refuel vessels with ventless filling in microgravity, the tanks and transfer system must be carefully thermally conditioned.
- The system developed is designed to be scalable upwards for larger depots, and downwards for use on supply tugs.
Detailed study
Detailed study
Two main scenarios were selected for this engineering study carried out by the space design office:
- Refueling debris collection missions on an 800 km sun-synchronous orbit (SSO) - increasing the amount of debris each collector can deorbit in its lifetime, to offer a more sustainable and cost-effective option for cleaning up space.
- Refuelling satellites in geostationary orbit (GEO) - with the aim of extending the life of satellites with a functional payload, but which do not have enough fuel to continue maintaining their position, thus reducing the number of satellites launched and then placed in graveyard orbits.
For the first scenario of SSO missions, Absolut System assumed that the debris collectors would refuel from a large SSO depot. Calculations showed that it was particularly advantageous to place small depots in specific orbits located close to the regions where debris is concentrated, in order to minimize the mass of propellant required for orbital maneuvering by the collectors.
CNES R&D Challenge
CNES R&D Challenge
Over the past year, Absolut System has been working on the development of a cryogenic propellant depot, as part of the CNES R&D Challenge for the reuse of the upper stage.
The use of depots and on-orbit refueling are essential for long-term lunar and Mars missions, as they enable multiple launch missions and reusable tugs in space. The use of smaller depots and refueling missions targeting more specific orbits could also help improve the sustainability of space operations.
The objective: to design a system capable of storing and transferring cryogenic propellants in orbit, with a view to being launched (filled) as a payload on a possible evolution of the Ariane launcher.
This development included an in-depth analysis of mission scenarios. Our cryogenic expertise was used for thermal modeling to optimize the ZBO (zero-boil off) system and to model the cryogenic propellant transfer process in microgravity.
Cryogenic innovations have long been essential to the space industry for a wide range of applications: imaging, propulsion, etc.
Detailed study
Detailed study
Two main scenarios were selected for the engineering study carried out by the space design office:
- Refueling debris collection missions on an 800km sun-synchronous orbit (SSO) - increasing the amount of debris each collector can deorbit in its lifetime, to offer a more sustainable and cost-effective option for cleaning up space.
- Refuelling satellites in geostationary orbit (GEO) - with the aim of extending the life of satellites with a functional payload, but which do not have enough fuel to continue maintaining their position, thus reducing the number of satellites launched and then placed in graveyard orbits.
For the first scenario of SSO missions, Absolut System assumed that the debris collectors would refuel from a large SSO depot. Calculations showed that it was particularly advantageous to place small depots in specific orbits located close to the regions where debris is concentrated, in order to minimize the mass of propellant required for orbital maneuvering by the collectors.
For missions in geostationary orbit, following a rendezvous in geostationary transfer orbit (GTO), the launcher can deliver cryogenic propellants to a reusable fuel tug, which will then transport them to GEO to refuel the satellites.
The system has been designed for two configurations: LOX/LCH4 and LAr. These were chosen for their compatibility with future Mars missions and their likelihood of use in future systems. However, these cryogenic propellants present several additional challenges which Absolut System will address in further studies:
- The tanks will require a combination of passive insulation and active cooling using a Turbo-Brayton cryocooler, to achieve long-term ZBO-type storage.
- To be able to refuel vessels with ventless filling in microgravity, the thruster and transfer system must be carefully thermally conditioned.
- The system developed is designed to be upgradable for larger depots, and downwards for use on supply tugs.
