ESA Offers €23,000 for 100 Days in Isolation: How to Apply for DLR’s New ‘Test Astronaut’ Studies

The European Space Agency (ESA) and the German Aerospace Center (DLR) are looking for volunteers willing to live like astronauts on a simulated Mars mission – or spend 60 days in bed – for up to €23,000 in compensation.

Cologne, Germany – December 3, 2025.

The dream of flying to Mars is still years away, but for six people, the next best thing could start much sooner – in a sealed lab in Cologne. ESA and DLR are currently recruiting “test astronauts” for two ambitious research studies that will simulate the physical and psychological challenges of long-duration spaceflight on Earth. Applications are open until 12 December 2025, and successful participants can earn €23,000 for a 100‑day isolation mission or around €18,000 for a 60‑day bed rest campaign. ^[1]

What Is SOLIS100? A 100‑Day Simulated Space Mission

The centrepiece of the current call is SOLIS100, a 100‑day isolation and confinement study to be run at DLR’s aerospace medicine research facility :envihab in Cologne in the first half of 2026. ^[2]

Goal: Study how 100 days in a cramped, isolated habitat affect health, behaviour, performance and well‑being. ^[3]
Operators: Initiated and funded by ESA, organised and conducted by DLR’s Institute of Aerospace Medicine. ^[4]
Location: The :envihab research facility at DLR Cologne, specifically a module configured as a small “space station” with individual sleeping pods, shared work areas and continuous monitoring. ^[5]
Schedule: The full campaign lasts 126 days, including preparation and recovery; the core isolation phase is 100 days. The current plan runs from 7 April to 7 August 2026. ^[6]

SOLIS100 is the follow‑up to an earlier 8‑day pilot campaign called SOLIS8, in which three women and three men simulated a space mission in the same facility. That short trial was used to fine‑tune procedures, tasks and the habitat layout for the much longer 100‑day study. ^[7]

The idea is simple but brutal: lock six people into a tightly controlled “space station” with limited resources, heavy monitoring, strict routines and no direct contact with friends or family – then watch how their bodies and minds adapt over time.

€23,000 for 100 Days Cut Off from the World

The headline that has grabbed public attention is the €23,000 expense allowance for SOLIS100. That’s what participants receive if they complete the entire 126‑day programme, including all pre‑ and post‑study testing. ^[8]

German and international media outlets have highlighted the unusual “job offer”:

The Hamburger Abendblatt reports that six “test astronauts” will spend 100 days in isolation and can earn €23,000, with applications accepted until 12 December. ^[9]
The easy‑language service nachrichtenleicht explains that ESA wants to know how six people cope with 100 days in a small station, and that each participant is to receive €23,000 for the effort. ^[10]
Tech and science outlets such as PC‑WELT and Golem have framed it as “23,000 euros for 100 days locked in a space lab” and emphasise the demanding conditions behind the seemingly attractive offer. ^[11]

What makes the money hard‑earned:

Total isolation from the outside world (beyond carefully controlled communications).
Continuous video monitoring in most areas, with real privacy only in the sleeping pod and bathrooms. ^[12]
Strict schedules, including scientific experiments, cognitive tests, exercise sessions and maintenance tasks for the “station”. ^[13]

In other words: it’s not 100 days of paid holiday – it’s 100 days of living and working like a real astronaut, just without the view of Earth.

Who Can Apply? ESA’s ‘Test Astronaut’ Profile

ESA and DLR are not looking for random couch potatoes. They want people whose profiles resemble those of real astronauts – physically and mentally robust, highly educated, and comfortable in international teams. ^[14]

According to DLR’s official call and media coverage, applicants for SOLIS100 must meet at least the following core requirements: ^[15]

Age: 25–55 years
Body mass index: Between 18.5 and 30 kg/m²
Health: Physically fit and able to pass a comprehensive medical and psychological examination, including lab tests, ECG and psychological screening
Language: Very good English skills – English is the working language for communication, procedures and research
Education: At least a Bachelor’s degree (a Master’s or equivalent experience is preferred)
Preferred backgrounds: Medicine, software engineering, technology or comparable technical/scientific fields; teaching experience is considered a plus

Citizens from EU/EEA countries can participate without a visa; non‑EU/EEA volunteers must be eligible for a long‑stay visa and residence permit for Germany. ^[16]

The selection process is multi‑stage and competitive. Candidates apply via DLR’s dedicated test‑subject portal, then go through questionnaires, medical checks and psychological assessments at DLR facilities in Germany. Only six people will ultimately form the international study crew. ^[17]

Inside the 126‑Day Mission: How SOLIS100 Works

SOLIS100 is designed to mimic the rhythm and constraints of a real long‑duration space mission. The campaign is divided into several phases: ^[18]

Team building (approx. 2 days)
- Participants arrive, meet each other and the study team, and go through briefings and simulations of typical tasks.
Baseline data collection (around 14 days)
- Extensive medical and psychological measurements establish each person’s “normal” state: fitness, sleep patterns, cognitive performance, mood and more.
Isolation phase (100 days)
- The crew move into the simulated space station module inside :envihab.
- They share a confined habitat with individual sleeping pods, shared workspaces and a small gym area. ^[19]
- The daily routine includes scientific experiments, maintenance tasks, scheduled exercise, meal preparation and group activities, all under camera surveillance.
Recovery phase (about 7 days)
- After the hatch opens, participants remain under observation while their bodies and minds readjust to “normal” life.
- Two additional follow‑up examinations are planned: around 30 days and again three to six months after the end of isolation. ^[20]

The environment is deliberately stressful:

Confined space: Six people share limited volume for 100 days.
Social isolation: No physical contact with the outside world and strictly filtered communication.
Operational pressure: Tasks are designed to simulate the complexity of real mission operations, including time‑critical procedures and coordination with “ground control.” ^[21]

Researchers will track everything from cardiovascular health and sleep quality to mood swings, group dynamics and performance on complex tasks – data that can feed directly into future mission planning.

SMC3: 60 Days in Bed for Space Science – and Around €18,000

Running in parallel with SOLIS100 is another major study: SMC3 (Sensorimotor Countermeasure Study), a bed rest campaign conducted by DLR in cooperation with NASA. ^[22]

While SOLIS100 focuses on isolation, SMC3 simulates microgravity by keeping participants in beds tilted 6 degrees head‑down for 60 days straight. ^[23]

Key points:

Total duration: About 88 days, including preparation, 60 days of strict bed rest and recovery. ^[24]
Posture: The bed is tilted so that the head lies slightly lower than the feet, causing body fluids to shift toward the head – similar to what happens in weightlessness. ^[25]
Goal: Test compact training methods and other countermeasures to reduce muscle loss, balance problems and other sensorimotor issues caused by long stays in low gravity. ^[26]
Participants: DLR is seeking 12 volunteers, often referred to as “terrestrial astronauts.” ^[27]
Compensation: Media reports and DLR information indicate an expense allowance of around €18,000 for full participation, with the same 12 December application deadline. ^[28]

Like SOLIS100, SMC3 has demanding medical and psychological criteria and is conducted under constant supervision at :envihab.

Why ESA and DLR Are Doing This: Preparing for Moon and Mars

Both SOLIS100 and SMC3 are part of a larger push by ESA and its partners to prepare for future human missions beyond low Earth orbit, particularly to the Moon and Mars. ^[29]

DLR emphasises several key challenges: ^[30]

A trip to the Moon takes only a few days, but a mission to Mars can involve months of travel in deep space.
Astronauts will live in tight habitats far from Earth, where evacuation is impossible and communication delays are significant.
They must work effectively as a team, manage limited resources and cope with the psychological strain of distance and confinement.
In parallel, their bodies have to withstand prolonged exposure to low gravity, which can weaken muscles, bones and balance systems.

Isolation and bed‑rest studies like SOLIS100 and SMC3 provide ground‑based analogues of these conditions. By analysing how well different personalities, training regimes and countermeasures work, scientists can refine selection criteria, onboard routines and medical support for future astronauts. ^[31]

In recent days, outlets from Welt to t‑online and international wire services have picked up the story, underscoring how significant these studies are for European human spaceflight. ^[32]

How to Apply: Steps for Interested Volunteers

For anyone seriously considering signing up, the process runs roughly as follows (always check the official DLR pages for the latest details): ^[33]

1. Online application

Applications for both SOLIS100 and SMC3 are submitted via DLR’s official test‑subject portal (“Probandensuche”).
The deadline is 12 December 2025, and places are limited (six for SOLIS100, twelve for SMC3). ^[34]

2. First screening

Initial checks verify basic criteria: age, BMI, education, language skills and self‑reported health status.
Candidates who pass this step may be invited to provide additional medical documentation from their own physicians. ^[35]

3. Medical and psychological exams

Shortlisted applicants travel to DLR facilities in Germany (Cologne and/or Hamburg) for detailed medical testing and psychological assessments specifically geared toward isolation and stress resilience. ^[36]
Background checks and proof of health insurance are also part of the process. ^[37]

4. Final selection and training

From all qualified candidates, the study team selects the final crews for SOLIS100 and SMC3.
Participants then receive detailed briefings, team‑building sessions and training on procedures, safety protocols and equipment before the campaigns begin in 2026. ^[38]

Is It For You? The Appeal – and the Risks

On paper, these offers sound tempting:

€23,000 for 100 days in a space‑station simulator
Around €18,000 for 60 days in bed

But the fine print makes clear that this is serious space medicine research, not an easy side hustle. Participants face: ^[39]

Long periods of social and sensory monotony
Physical discomfort from confinement or head‑down tilt
Intensive testing and monitoring
A full‑time commitment for months, with limited freedom to move or make personal plans

On the plus side, volunteers get:

A chance to contribute directly to future Moon and Mars missions
A unique, highly structured environment that few people ever experience
Close medical monitoring and insights into their own health and resilience

Anyone thinking about applying should realistically assess their ability to handle isolation, strict routines and physical strain, and rely on discussions with medical professionals for personal health questions. The official DLR and ESA information remains the authoritative source for risks, requirements and conditions.

Bottom Line

As of 3 December 2025, ESA and DLR’s call for “test astronauts” is one of the most talked‑about space stories in Europe:

Six people are wanted for SOLIS100, a 100‑day isolation mission in Cologne, paid €23,000. ^[40]
Twelve more will be selected for SMC3, a 60‑day bed‑rest study that pays around €18,000. ^[41]
Both projects are key stepping stones toward future Moon and Mars expeditions, and both remain open for applications until 12 December 2025. ^[42]