Description
The objective of the activity is to develop high fidelity models to allow the mission design of satcom constellations in VLEO. An in-orbit experiment will be designed and manufactured to measure key geographically and time dependent atmospheric parameters (density, radiation, ionospheric, chemical composition etc..) as well as satellite flight parameters (including drag, solar cells efficiency, etc..). These measurements will enable the precise modelling of VLEO systems (incl. orbital mechanics, budgets, system sizing, etc.). Targeted Improvements: Enable precise VLEO orbital mechanics modelling and system sizing.Description: Due to the variability of the atmospheric conditions, the knowledge of environmental and atmospheric data (density, radiation level, chemical composition) is challenging to get, however in-situ measurements are critical to properly design attitude control processing chain. Previous in-orbit experiments have been attempted in the past but have met with limited mission success. Future VLEO satcom constellations are needed to operate for extended periods of time and will need to be resilient to highly variable environments yet providing viable system architecture. The precise orbital mechanics modelling is then crucial for the sizing of the telecommunication systems in VLEO. This in-orbit experiment will gather the relevant data of the orbital space environment in order to generate the flight dynamics modelling required for the AOCS control loop. This will benefit satellites in orbits ranging from 200km-400km, covering VLEO applications. To provide the needed measurements for the atmospheric models, a payload will be designed, including all the necessary sensing instruments. The spacecraft will be launched to a relevant orbit and in situ measurements will be gathered and communicated to ground over the operational lifetime. The key parameters to acquire and process will be: neutral atmosphere density, radiation, chemical composition and ionospheric parameters. In addition to these primary goals, secondary goals suggested by the bidders are invited (e.g. materials resistance to VLEO environment, solar cell ageing, etc.). In designing the experiment, the activity will consider important trade-offs such as:- Single vs multi spacecraft mission profiles- Life extension via on board propulsion- Co- or multi-orbit ISL to improve data latency and data recovery for very low orbits.The activity will allow design, develop or adapt existing payloads,select a host platform, integrate, launch and operate the payloads for the required time, analyse the acquired data, improve the current models and report on the next steps. In addition to the experimental campaign, the activity will include the review and improvement of current available atmospheric models, allowing for modelling improvements through correlation from the gathered in-orbit data. The minimum duration of the flight experiment will be 1 year in order to characterise and measure the atmospheric conditions in VLEO including seasonal atmospheric variability. Footnote: On Delegation Request activities will only be initiated on the explicit request of at least one National Delegation.