Assemble and depart
The departure concept assumes orbital refuelling and a high-energy launch stage. An approximately 8 km/s stage velocity increment is an assumption requiring vehicle and mission analysis.
STARSHOT AEROSPACEContact 
INTERSTELLAR SPACE / LONG-DURATION OBSERVATORY
Heliofugal Explorer
A long-duration probe concept for studying the heliosphere and the local interstellar medium beyond it.
Fast Interstellar and Heliosphere Probe
Exploring a faster route to interstellar measurements.
The study combines a high-energy Earth departure with a Jupiter gravity assist and a separable nuclear-electric propulsion stage. It targets a final Sun-relative speed near 60 km/s, equivalent to roughly 12.7 astronomical units per year. This is a design objective. Achievability depends on the trajectory and a consistent mass, power and propulsion model.
Preliminary concept; propulsion feasibility unresolvedMISSION VISUALISATION
From Jupiter to interstellar space.
Visualisations of the proposed spacecraft during encounter, powered departure and independent cruise.
Blender concept renders. Jupiter map: NASA/JPL/Space Science Institute.
01Jupiter departure
The concept uses electric propulsion after a Jupiter encounter to increase the departure speed.
02Jupiter encounter
A proposed Jupiter flyby would change the trajectory and provide an opportunity for planetary observations.
03Interstellar cruise
The separated science probe would continue towards the heliopause and the interstellar medium.
CURRENT STUDY
Mission at a glance.
- Launch assumption
- Refuelled Starship departure architecture
- Earth departure target
- Approximately 8 km/s stage increment
- Jupiter event
- Close gravity assist
- Electric stage target
- Up to approximately 45 km/s delta-v
- Xenon concept
- Approximately 1.5 tonnes
- Final speed objective
- Approximately 60 km/s / 12.7 AU per year
- Science-probe class
- Approximately 1 tonne after stage separation
- Lifetime objective
- 50–100 years; feasibility unverified
MISSION PROFILE
From departure to science operations.
The sequence is a mission concept. Timings and performance targets require trajectory and system analysis.
Aim for Jupiter
The cruise would target a Jupiter gravity assist with suitable clearance from atmospheric and radiation hazards.
Build escape speed
A nuclear-electric stage in the approximately 25 kW class is proposed for a multi-year ion-thrust campaign. Reactor mass, heat rejection and thruster efficiency would determine its performance.
Separate the stage
The propulsion stage would separate at a planned point after completing its useful thrust campaign. The science probe would then continue independently.
Cross the heliosphere
Instruments would measure fields, plasma and particles across the outer heliosphere and beyond the heliopause, where solar wind gives way to the interstellar medium.
Operate for generations
A long-duration operating plan would reduce instrument activity as power declines. Component life and communications performance would constrain the useful mission duration.
SPACECRAFT ARCHITECTURE
Candidate spacecraft systems.
These systems describe the proposed design and the work needed to assess it.
Propulsion stage
The candidate stage combines ion thrusters with approximately 1.5 tonnes of xenon and a nuclear-electric power system. Its mass and achievable velocity change remain unresolved.
Cruise probe
The science probe is provisionally in the one-tonne class after stage separation. This allocation must include instruments, communications and long-life power equipment.
Power philosophy
Multiple radioisotope units and interconnected electrical sections are being considered to limit the effects of individual failures.
Attitude control
Candidate pointing hardware includes reaction wheels, star trackers and small thrusters. Their lifetime and momentum-management needs require analysis.
Science
The proposed payload would study magnetic fields, plasma and energetic particles alongside dust and neutral atoms. Additional astronomy instruments remain options.
Communications
A high-gain antenna and onboard storage would support data return as distance increases. Antenna size, transmit power and Earth receiving capacity would set the data rate.
PROPOSED SCIENTIFIC PARTNERSHIP MODEL
A proposed framework for partner instruments and observations.
A future agreement would define instrument accommodation and integration along with operations and data delivery. Starshot would operate the spacecraft. Development would depend on an agreed scope and sufficient committed funding.
Hosted science
Long-life instruments could be proposed by teams studying heliophysics, planetary science and the interstellar environment.
Observation campaigns
Observation campaigns would need to fit the departure trajectory and the spacecraft pointing and power limits.
Data services
Institutional support could fund instrument operations and long-term archiving of calibrated measurements.
Legacy participation
Agencies, universities and foundations could support defined elements of a staged development programme.
ReservationPaid capacity hold following competitive selection
IntegrationStaged fees for interface review, qualification and delivery
Flight serviceContract covering launch, operations, downlink and data delivery
ExtensionRenewable operations or relay service after the prime mission
Financial assessment would compare committed funding with the full cost of development and operations. It would also account for launch, integration and insurance alongside contingency and financing costs.
ENGINEERING PRECEDENT
References informing the study.
NEXT STEPS
The speed and lifetime targets require a consistent propulsion design and a credible plan for decades of operation.
Mission-specific figures are preliminary targets or assumptions. They may change as the trajectory and system designs are developed. The references describe relevant science and prior missions; they do not validate this proposed spacecraft.
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