Dear Physics of the Cosmos Community,

At the PhysPAG Executive Committee (EC) retreat May 20-21, the EC and SIG chairs discussed feedback and questions received so far from all of you regarding the ASTRA Initiative, and so we are writing to you to provide some clarification and to announce a PhysPAG Community Webinar on the ASTRA Initiative on Tuesday, 02 June at 2p-3p Eastern / 11a-12p Pacific.

The ASTRA Initiative will develop selected mission concept studies to Concept Maturity Level (CML) 3 and Manufacturing Readiness Level (MRL) of ~3 to 4, will identify tall-pole and long-lead technologies that the Astrophysics Division should prioritize and invest in, and will highlight science priorities, including those that have changed since Astro2020.

The ASTRA Initiative charged the PAGs with collecting concepts but deliberately left the process to the PAGs to define, with the expectation that it might look different for each community. In PhysPAG, we have asked each Science Interest Group (SIG), through their chairs and EC members, to collect and synthesize community input on science drivers, capabilities, and technologies that will motivate consideration of potential large (>~$1B) mission concepts for implementation in the next decade or two. Some SIGs have set up Science Analysis Groups (SAGs) to steer this process. There is a short window to build a community consensus before the Ad ASTRA workshop 1-3 September 2026. We are requesting help from the community to summarize the status of space-based instrumental capabilities and describe how these can be deployed to address compelling science questions of broad interest within astrophysics. Your SIG chairs can be found on the web pages for each SIG and are working closely with the EC to collect your input, answer your questions, and provide feedback, especially where similar inputs indicate a strong community interest in particular science questions and capabilities. The concepts entering the ASTRA Initiative will start from driving science questions and will propose an exploration of the trade space for implementation options. While mission concept studies at any maturity level can be submitted at this point, we would like to encourage everyone to work with their relevant SIGs and SAGs and, where possible, synthesize individual ideas into larger mission concepts with a wide scope that are supported by a large fraction of the relevant community. 

Brief Mission Concept Description documents are requested with a deadline of 26 June 2026. A submission form will be made available soon via the ASTRA website.  An updated and simplified template is also available to simplify the process of submitting the mission concept ideas that the community wants to study. Some concepts may not yet be sufficiently developed to address all the questions posed (e.g., critical technologies may be undefined, detector temperature may be unknown). In such cases, respondents should indicate “TBD” (to be determined) or omit parameters that are not applicable. At this stage, concepts will not be penalized for limited maturity. Concepts of all maturity levels are encouraged.

If you have submitted your mission concept description document already, there is no need to update it according to the new template.

For more information and resources related to the ASTRA Initiative, please see this page. Questions about the ASTRA Initiative can be submitted here; collected questions and answers are available here. We are very grateful for the enthusiasm we have received from the PhyCOS community, and are looking forward to receiving your input to the ASTRA process. 

Thanks, 

Manel Errando (Washington University in St Louis) on behalf of the PhysPAG EC