Thermal Simulation

Simulate thermal behavior of compute hardware in orbital environments, including eclipse cycles and varying solar flux.

Status: Early Access — Request API key

Overview

Space presents unique thermal challenges:

No convection — Heat can only be rejected via radiation
Eclipse cycles — Periodic loss of solar heating
Solar flux variation — Changes with orbit and season
Internal heat — Compute generates significant waste heat

Quick Start

from rotastellar import RotaStellarClient

client = RotaStellarClient(api_key="rs_...")

thermal = client.planning.thermal(
    orbit="LEO-550",
    power_dissipation_w=500,
    radiator_area_m2=2.0,
    internal_mass_kg=100
)

print(f"Steady state: {thermal.steady_state_c}C")
print(f"Max (sunlit): {thermal.max_temp_c}C")
print(f"Min (eclipse): {thermal.min_temp_c}C")
print(f"Thermal margin: {thermal.margin_c}C")

import { RotaStellarClient } from '@rotastellar/sdk';

const client = new RotaStellarClient({ apiKey: 'rs_...' });

const thermal = await client.planning.thermal({
  orbit: 'LEO-550',
  powerDissipationW: 500,
  radiatorAreaM2: 2.0,
  internalMassKg: 100
});

console.log(`Steady state: ${thermal.steadyStateC}C`);
console.log(`Max temp: ${thermal.maxTempC}C`);

curl https://api.rotastellar.com/v1/planning/thermal \
  -H "Authorization: Bearer rs_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "orbit": "LEO-550",
    "power_dissipation_w": 500,
    "radiator_area_m2": 2.0,
    "internal_mass_kg": 100
  }'

Parameters

string

required

Orbit specification. Options:

LEO-400 to LEO-600 — Low Earth Orbit at specified altitude
MEO-2000 to MEO-20000 — Medium Earth Orbit
GEO — Geostationary orbit
Custom: {"altitude_km": 550, "inclination_deg": 53}

number

required

Internal heat generation in watts

number

required

Radiator surface area in square meters

number

Internal thermal mass in kg (affects transient response)

number

default:"0.9"

Radiator emissivity (0-1)

number

default:"0.3"

Solar absorptivity (0-1)

Response

{
  "steady_state_c": 35.2,
  "max_temp_c": 52.8,
  "min_temp_c": 12.4,
  "margin_c": 17.2,
  "eclipse_duration_min": 35.5,
  "sunlit_duration_min": 57.3,
  "cooling_rate_c_per_min": 0.65,
  "heating_rate_c_per_min": 0.48,
  "thermal_profile": [
    {"time_min": 0, "temp_c": 35.2, "phase": "sunlit"},
    {"time_min": 57, "temp_c": 52.8, "phase": "eclipse_start"},
    {"time_min": 92, "temp_c": 12.4, "phase": "eclipse_end"}
  ],
  "recommendations": [
    "Consider active thermal control for tighter bounds",
    "Heaters recommended for eclipse survival"
  ]
}

Thermal Profiles

LEO Thermal Cycle

Temperature (C)
     60 |    ____
        |   /    \
     40 |  /      \____
        | /            \
     20 |/              \
        +-----------------> Time
         Sunlit  Eclipse

Operating Limits

Component	Min (C)	Max (C)
GPU/TPU	0	85
CPU	-20	100
Memory	-40	85
Storage	-40	70
Battery	0	45

Advanced: Time-Series Simulation

Get detailed thermal behavior over multiple orbits:

thermal = client.planning.thermal(
    orbit="LEO-550",
    power_dissipation_w=500,
    radiator_area_m2=2.0,
    simulation={
        "duration_orbits": 10,
        "time_step_sec": 60
    }
)

# Plot thermal profile
for point in thermal.time_series:
    print(f"{point.time_min}: {point.temp_c}C ({point.phase})")

Design Considerations

Radiator sizing

Larger radiators = lower steady-state temperature but more mass and cost. Rule of thumb: 0.1-0.2 m² per 100W dissipation for LEO.

Eclipse survival

Ensure minimum temperature stays above component limits. May require heaters or thermal mass.

Hot case analysis

Consider worst-case solar flux (perihelion + beta angle = 0). Add 10-15% margin to maximum temperature.

Getting Started

Planning Tools

Orbital Intelligence

CAE

Operator Agent

Mission Control

Orbital Runtime

Orbital Sim

Distributed Compute

SDKs

Resources

Thermal Simulation

Thermal Simulation

Overview

Quick Start

Parameters

Response

Thermal Profiles

LEO Thermal Cycle

Operating Limits

Advanced: Time-Series Simulation

Design Considerations

Next Steps

Latency Simulation

Power Budgeting

​Thermal Simulation

​Overview

​Quick Start

​Parameters

​Response

​Thermal Profiles

​LEO Thermal Cycle

​Operating Limits

​Advanced: Time-Series Simulation

​Design Considerations

​Next Steps

Latency Simulation

Power Budgeting

Thermal Simulation

Overview

Quick Start

Parameters

Response

Thermal Profiles

LEO Thermal Cycle

Operating Limits

Advanced: Time-Series Simulation

Design Considerations

Next Steps