(Apologies for cross-posting, but please forward to colleagues/redistribute) ** *PITHIA-NRF Trans-National Access (TNA) 2^nd Call* PITHIA-NRF (Plasmasphere Ionosphere Thermosphere Integrated Research Environment and Access services: a Network of Research Facilities) invites applications for access to a variety of research facilities for studies and modelling of physical processes acting in the Earth’s upper atmosphere, with support from experts within the field. There are twelve nodes within PITHIA-NRF all dedicated to investigating the plasmasphere, ionosphere and/or thermosphere. The access can be *physical access* (one-week visit with travel and accommodation included) or *remote access* (one-month remote access with weekly support). The available services or resources are limited, and a competitive process is required following a defined procedure and criteria for the selection of users. *Project opportunities:* Information of project opportunities and description of the nodes are available at https://pithia-nrf.eu/tna/tna-calls/second-tna-call. We encourage any potential applicants to discuss with the relevant node about the project before submitting their proposals. The TNA Support Centre (tna(a)pithia-nrf.eu) at PITHIA-NRF can help establishing contact points with the nodes. *When?* The call is open from *1 J**anuary**202**2* until the deadline *15 March**202**2*. The application can be submitted at any time between these dates. *Who?* Access is provided for science projects to users from Academia, Small and Medium Enterprises, Industry, and Public Organisations. *How?* The application should be filled in and submitted using the online form (https://pithia-nrf.eu/forms/tna-application-form- <https://pithia-nrf.eu/forms/tna-application-form-2>2 <https://pithia-nrf.eu/forms/tna-application-form-2>). After submission, eligibility and feasibility checks will be performed followed by the scientific evaluation. Follow the instructions at https://pithia-nrf.eu/tna/tna-calls/second-tna-call. *Contact:* TNA Support Centre: tna(a)pithia-nrf.eu /EU Horizon 2020 Research and Innovation Programme Grant Agreement No 101007599/ -- Dr. Ingemar Häggström Leader of WP7: PITHIA-NRF Trans-national access