Research directions, full treatment

Each direction is defined by two things: which documented constraint it escapes, and what must be true for it to win. Founding document of the Surya program; adapted from theoriginating articleat space.narada.systems.

R1Space-ified terrestrial silicon

The workhorse. Near-term, highest confidence.

Ultrathin crystalline silicon with polymer encapsulation, no coverglass, radiation self-annealing — the route Solestial and Source Energy are already flying (~$5/W modules, flight-proven). Nothing here needs inventing; it needs characterizing.

• Annealing kinetics at real operating temperatures as a function of wafer thickness and doping — the mechanism exists in the literature but is not yet creditable at the 100 µm n-type design point.
• Handling yield below 100 µm: breakage climbs from ~10% at 100 µm to ~96% at 70 µm. Carriers, edge reinforcement, kerfless methods.
• Atomic-oxygen protection without glass: ETFE, SiO₂ nanolaminates, sacrificial coatings.

Wins if: end-of-life degradation becomes predictable and boring — an actuarial input rather than a research question.

R2Perovskite and perovskite/Si tandems

The upside bet. Mid-term.

Self-healing under irradiation, specific power above 1 kW/kg, projected $5–15/W at maturity. The tandem escapes every materials chokepoint at once: no germanium, no gallium worth counting, no glass.

• Multi-year stability under combined UV, ATOX, and thermal cycling — single-stressor data exists; the coupled dataset does not, anywhere.
• Encapsulation as the actual product — the cell is easy; keeping it alive is the company.
• Qualification protocols: none exist for this class. Writing the test standard is itself a research direction with unusual leverage — whoever defines the protocol defines everyone's market entry cost.

Wins if: a credible 5-year LEO degradation model survives independent replication.

Readiness baseline, August 2026 (two independent research sweeps, corroborated): flight heritage exists and is recent and thin — MAPHEUS-8 (2019, first perovskites in space), a ~10-month ISS MISSE exposure whose degradation was >90% reversible, ~100 days on an RIT CubeSat with no observable degradation, plus Big Red Sat-1 and RHOK-SAT. Readiness sits at TRL 4–5, trending 6. The gap is duration and coupled stressors, not existence. Recorded as proposalep_1ca635b3 in the family epistemic graph; narrative record in the space ledger,Entry 888.

R3Substrate liberation: ELO/IMM

The geopolitical hedge. Mid-term.

Epitaxial lift-off and inverted metamorphic growth separate the III-V junction from the germanium wafer. The wafer becomes a reusable template instead of a consumable — the only direction that attacks the germanium chokepoint while keeping III-V performance.

• ELO throughput and yield at industrial scale — today it is a laboratory courtesy.
• Substrate reuse cycle count: ~10 cycles is the threshold where germanium exposure drops by an order of magnitude.
• IMM mechanical reliability without the handle wafer: what holds the cell together once the germanium leaves.

Wins if: reuse economics close at constellation volumes. Watch MicroLink and the Rocket Lab/AZUR process disclosures.

R4III-V on alternate lattices

A watching brief, not a program.

Metamorphic III-V on silicon, GaAs substrates (recyclable but still gallium), sapphire. Honest assessment: trades a structural chokepoint for a defect-physics problem. Threading dislocations and CTE mismatch over 30,000 thermal cycles are soluble in principle and unrewarding in practice so far.

Wins if: someone else's metamorphic-buffer breakthrough makes it cheap to revisit. Check annually, fund never.

R5In-space cell manufacturing

The long game. Far-term, and uniquely aligned with this program.

Deposit thin-film cells directly onto deployed membranes in orbit. Vacuum is free up there; launch mass collapses to feedstock; coverglass becomes optional when nothing has to survive the fairing. The only direction that escapes substrate, coverglass, andlaunch mass in one move.

• Deposition rate and film quality in uncontrolled vacuum, on non-ideal substrates, with thermal drift.
• Contamination of the host platform — the coater and the array must not poison each other.
• Repair and re-coat as a service model: a coating pod visiting a membrane is an ISAM mission profile, and composes with on-orbit attachment architectures.

Wins if: deposited specific power beats launched specific power after accounting for the coater's own mass and operations. Nobody else is motivated to build this.

R6System architecture as research

Cross-cutting. Cheap to do now, compounding returns.

The ISCR analysis showed the move: integrate solar, radiator, and compute so the dedicated panel structure disappears (~500 W/kg at array level).

• High-voltage array design to cut harness mass.
• Mass-production panel standardization — the Starlink lesson: the cost was never the cell.
• Qualification economics: cheap, fast radiation-test campaigns that let new materials accumulate credible heritage without a decade-long dossier. Attacks the filing-cabinet moat directly and benefits every other direction.

R7Non-photovoltaic solar: the closing argument

One sweep, then retire.

Solar-thermal Stirling, thermionics, thermophotovoltaics with concentrators. Almost certainly dominated by photovoltaics on both $/W and W/kg — but the honest closing argument with current numbers has never been written. A single reading sweep retires the question permanently instead of leaving it as background noise in every trade study. The space-unique variants (permanent source+sink, eclipse-cycle harvesting, thermoradiative laminates, tethers, solar-pumped lasers) were audited and closed in August 2026; see theclosed table.