Mission Proposal: AragoScope Solar Observatory (ASO)

Proposal Submitted to: @esa

Date: 20 February 2025

Principal Investigator: @R34lB0rg

1. Scientific Objectives

The AragoScope Solar Observatory (ASO) aims to deliver groundbreaking insights into the Sun’s chromosphere and corona through sub-meter resolution imaging, tackling key questions in heliophysics aligned with ESA’s Cosmic Vision 2015-2025 theme, “The Hot and Energetic Universe.” By exploiting the Arago/Poisson Spot diffraction phenomenon, ASO will surpass the limitations of classical telescopes to address:

1. Coronal Heating Processes: Resolve sub-kilometer magnetic structures (e.g., nanoflares, Alfvén waves) to explain the corona’s 1-3 MK temperature anomaly versus the photosphere’s 5,500 K.
2. Coronal Loop Evolution: Image loop footpoints and plasma dynamics at 0.1-1 m to uncover formation and energy transfer mechanisms.
3. CME Initiation: Identify pre-eruption magnetic instabilities (~1-100 m) to enhance space weather prediction.
4. SEP Sources: Map flare and CME acceleration sites (~1-10 m) to refine solar radiation models.
5. Solar Wind Origins: Resolve coronal hole plumes (~1-10 m) to connect fine-scale structure to heliospheric flows.
6. Flare Fine Structure: Image reconnection events (~1-100 m) to quantify energy dissipation and scaling.

These objectives support ESA’s goals of understanding solar-terrestrial interactions and fundamental astrophysical processes.

2. Scientific Background and Rationale

The Sun’s corona remains a frontier of unresolved physics—its extreme temperature, cyclic sunspots, and eruptive phenomena drive space weather yet defy detailed observation. Classical ground-based telescopes, such as the 4 m Daniel K. Inouye Solar Telescope (DKIST), achieve ~15 km resolution using adaptive optics and filters reducing light to 0.1%, but atmospheric distortion limits finer scales. Space-based systems like ESA’s Solar Orbiter (~70 km resolution at perihelion) and NASA’s SDO (~725 km) mitigate this, yet face detector saturation (~10⁻⁵ W) and thermal noise from heated optics, capping resolution far above sub-meter needs.

Coronal features—magnetic loops (~10-100 km), flare kernels (~1-100 m), and CME onset zones (~1000 km)—demand finer imaging to decode their physics. The AragoScope, using diffraction around an opaque disc, avoids these constraints, offering a scalable, heat-resistant alternative validated by Arago’s 1818 discovery and modern diffraction optics.

3. Mission Design and Technical Approach

3.1 Instrument Concept: AragoScope

• Opaque Disc: A 17.5 km diameter inflatable balloon (aluminized Mylar/Kapton, 0.1 kg/m², ~24 tonnes), deployed at 0.5M km from the Sun (~2° subtension), fully occults the 1.39M km photosphere.
• Detector System: A 10 m segmented mirror or SNSPD array, cryocooled (-270°C), positioned 57,000 km behind in the ~17.5 km shadow, capturing the Arago Spot.
• Wavelengths: Targets coronal UV/X-ray (e.g., 171 Å Fe IX), with H-alpha (656 nm) as secondary.
• Resolution: For λ = 171 Å, D = 17.5 km, θ ~ 1.2 * 10⁻⁹ arcsec (~0.4 mm at 0.5M km; ~0.9 m at 1 AU). A 1 km disc with hybrid optics achieves ~0.1-1 m.

3.2 Orbital Configuration

• Disc Orbit: 0.5M km from Sun (~0.0033 AU), sun-synchronous alignment.
• Detector Orbit: 57,000 km trailing, stabilized via micro-thrusters.
• Trajectory: Launch to L2 (1.5M km from Earth), then inward adjustment.

3.3 Technical Specifications

• Mass: Balloon (~24 tonnes), Detector (~5 tonnes), compatible with Ariane 6 (multi-launch).
• Power: Detector solar panels (100 kW), minimal balloon needs (inflation/stabilization).
• Data Transmission: 10 Gbps via laser comms to ESTRACK.
• Lifetime: 5 years, extensible via servicing (e.g., ESA robotic platforms).

3.4 Development and Feasibility

• Heritage: Builds on ESA’s inflatable tech (e.g., Gaia sunshield) and NASA’s Echo balloons; SNSPDs proven in X-ray missions (e.g., XMM-Newton).
• Challenges: Alignment precision (µm), balloon integrity (micrometeoroids), thermal control. Addressed via redundant segments, graphene composites, and cryocooling.

4. Expected Scientific Return

• Data Outputs: Sub-meter coronal maps (loops, sunspots, plumes) in UV/X-ray; dynamic flare/CME sequences.
• Outcomes: Clarify coronal heating (nanoflare vs. wave dominance), improve CME/SEP forecasts (10-100x precision), link solar wind to coronal structure.
• Synergy: Enhances Solar Orbiter, PROBA-3, and ground-based data with finer resolution.

5. Budget and Schedule

5.1 Cost Estimate (Preliminary)

• Development: €450M (balloon, detector, optics R&D).
• Launch: €100M (Ariane 6, multi-payload).
• Operations: €80M (5 years, ground segment).
• Total: ~€630M, within ESA M-class mission range (e.g., Solar Orbiter, €550M).

5.2 Schedule

• Phase A (2026-2027): Concept refinement, balloon prototyping.
• Phase B (2028-2030): Design, testing (e.g., stratospheric analogs).
• Phase C/D (2031-2033): Build, launch via Ariane 6.
• Phase E (2034-2039): Operations, data analysis.

6. Strategic Relevance and Impact

• Scientific: Advances ESA’s leadership in heliophysics, addressing Cosmic Vision priorities.
• Technological: Pioneers inflatable diffraction optics, transferable to exoplanet or stellar missions.
• Societal: Strengthens space weather resilience, protecting European infrastructure and missions.

7. Conclusion

The AragoScope Solar Observatory offers ESA a transformative instrument to probe the Sun’s corona at sub-meter resolution, resolving long-standing heliophysical questions—coronal heating, CME initiation, SEP acceleration, and solar wind origins. By overcoming classical telescope limitations with a proven diffraction principle and scalable balloon technology, ASO aligns with ESA’s mission to explore the energetic universe. Ancient cultures—Egyptians with Ra, Chinese with lóng—saw the Sun as alive; at 0.1-1 m, ASO might reveal intricate plasma physics or, improbably, patterns hinting at their mythic vision. We propose ESA fund ASO to illuminate the Sun’s dynamic edge and its influence on our Solar System.