COST Action proposal · Open Call oc-2026-1

Stratospheric vehicle design — a roadmap for the challenges ahead

A European network in preparation, bringing together the disciplines that stratospheric flight requires and that today work apart from one another.

Collection date: 28 October 2026

The challenge

Uncrewed platforms flying between 18 and 22 km can provide persistent regional connectivity, continuous environmental observation and communications that survive the loss of ground infrastructure. Demonstrators have flown. What does not yet exist is a dependable, reproducible engineering basis for designing such vehicles.

The problem resembles neither conventional aviation nor spaceflight. Air density is a small fraction of its sea-level value, structures reach a slenderness at which linear aeroelastic theory no longer holds, aerodynamic surfaces work at Reynolds numbers where established correlations lose validity, and every constraint feeds a single energy balance that has to close across a full day and night.

Research groups across Europe address these questions in isolation, with different reference cases, different test protocols and different descriptions of the atmosphere. Results diverge for reasons unconnected to the physics, and progress inside each discipline does not accumulate across the field.

What the Action would produce

An agreed specification of the stratospheric design environment between 18 and 22 km, used as the common input to every Working Group.

An open benchmark and validation suite of coupled reference cases, so that independently developed methods can be compared directly for the first time.

Harmonised protocols for accelerated ultraviolet, thermal and mechanical ageing of thin films and ultra-light composites, validated through an inter-laboratory round-robin campaign.

Interface conventions that allow structures, aerodynamics, propulsion, energy and the atmospheric environment to be treated as one coupled system rather than in sequence.

A European Stratospheric Flight Design Roadmap setting out what is technically settled, what remains genuinely open, and what regulators need in order to act.

What joining involves

COST funds networking from its own budget. Joining the network at proposal stage carries no financial commitment, no co-funding, no institutional contribution and no letter of intent. No budget is requested from participants.

A researcher may hold a role in only one proposal per COST collection. Participation means an e-COST profile and a named place in one of the four Working Groups.

Working Group membership stays open after approval, and early-career researchers take real coordinating roles rather than nominal ones.

Taking part

To join the Network of Proposers, fill in the partner form below and send it back by e-mail. One row per person, and a second row if a younger colleague from the same group joins as a proposer in their own right. The data is used only to issue the formal e-COST invitation; it is not published on this site.

The draft Technical Annex above is the working version, not the submitted one. Comments are welcome by e-mail at any point before the collection date — quoting the section number (1A, 2B, 3C and so on) helps. The text names no participant, institution or country, because the proposal is evaluated anonymously. melihy@erciyes.edu.tr

Updates

18 September 2026Draft Technical Annex open for comment

The full draft Technical Annex is now downloadable from this page. Prospective and current partners are invited to comment by e-mail before the collection date; quoting the section number (1A, 2B, 3C and so on) makes the comments easy to fold in. The text names no participant, institution or country, because the proposal is evaluated anonymously.

18 September 2026Open places: aviation law, materials ageing, test infrastructure, industry

Four areas are still being sought before the collection date: aviation law with certification and airspace integration; accelerated ageing of thin films and ultra-light composites; structural metrology and experimental facilities; and industrial partners in composite production and aerospace systems. Groups working in these areas are welcome to make contact.

14 September 2026Network spans institutions in nine countries

Partner declarations collected through September bring the network to twelve institutions across nine countries, two thirds of them Inclusiveness Target Countries. The share of researchers under 40 stands at 54 per cent, comfortably above the 40 per cent COST requires.

8 September 2026Concept note circulated to prospective partners

A concept note describing the challenge, the four Working Groups and the intended outputs was sent to prospective partners, together with a short form for the data an e-COST invitation requires.

26 August 2026Preparation started for Open Call oc-2026-1

Preparation of the proposal began for the COST Open Call oc-2026-1, whose collection date is 28 October 2026.