{
  "title": "Electric propulsion ranges in NASA's 2026 small-spacecraft survey",
  "source": "NASA Small Spacecraft Technology State of the Art, 2026 edition, In-Space Propulsion, Table 4-1",
  "source_url": "https://www.nasa.gov/smallsat-institute/sst-soa/in-space_propulsion/",
  "source_scope": "Ranges summarize devices covered in NASA's small-spacecraft survey and are not universal limits for these technologies.",
  "plot_type": "Two separate logarithmic min-to-max range plots: thrust and specific impulse.",
  "interpretation_limit": "The thrust endpoints and specific-impulse endpoints are independent survey ranges, not paired data for the same devices, operating conditions, or a single engine's full performance curve. The plots do not identify a universally best technology.",
  "endpoint_qualifications": "The Hall-effect minima in NASA Table 4-1 (0.25 mN and 200 s) are rounded summary bounds: Table 4-10 lists the MUSIC-SI row as <0.25 mN and <200 s. The exact lower values are unknown. The electrospray 20 μN endpoint is the lowest nominal value listed in the summary, not a minimum operating capability: NASA's 2017 ST7 flight-performance paper reports four-head CMNT assemblies with each head individually throttleable from 5 to 30 μN. The 2026 Table 4-8 row “4 x 20” is therefore best read as four heads at 20 μN each; 80 μN is an arithmetic simultaneous sum, not an asserted measured flight point. NASA's live HTML [mN] label conflicts with its PDF [μN] and primary flight paper and appears to be a factor-1000 label/version error.",
  "thrust_units": "mN",
  "specific_impulse_units": "s",
  "data_file": "small-spacecraft-electric-ranges.csv",
  "generator": "generate_trade_space.py",
  "outputs": [
    "small-spacecraft-electric-ranges.svg",
    "small-spacecraft-electric-ranges-mobile.svg"
  ],
  "technologies": [
    {
      "name": "Electrothermal",
      "thrust_mN": [
        0.1,
        1000
      ],
      "specific_impulse_s": [
        20,
        350
      ]
    },
    {
      "name": "Electrospray",
      "thrust_mN": [
        0.02,
        20
      ],
      "specific_impulse_s": [
        225,
        3000
      ]
    },
    {
      "name": "Gridded ion",
      "thrust_mN": [
        0.1,
        20
      ],
      "specific_impulse_s": [
        500,
        3000
      ]
    },
    {
      "name": "Hall effect",
      "thrust_mN": [
        0.25,
        55
      ],
      "specific_impulse_s": [
        200,
        1920
      ]
    },
    {
      "name": "Pulsed plasma / vacuum arc",
      "thrust_mN": [
        0.004,
        0.5
      ],
      "specific_impulse_s": [
        87,
        3200
      ]
    },
    {
      "name": "Ambipolar",
      "thrust_mN": [
        0.5,
        17
      ],
      "specific_impulse_s": [
        400,
        1100
      ]
    }
  ],
  "checked_claims": [
    "NASA notes that electric propulsion generally has lower thrust-to-power than chemical propulsion and may need hundreds or thousands of operating hours to provide similar total impulse.",
    "The survey usually considers systems including propellant feed, storage and power processing, but not the spacecraft electric power supply; some rows describe components rather than complete systems.",
    "Hall thrusters generally have higher thrust-to-power than gridded-ion thrusters in NASA's comparison, while gridded-ion devices can reach higher specific impulse."
  ],
  "reproduction": "Run python generate_trade_space.py in this directory. The script writes the CSV and wide/phone SVGs using only Python's standard library.",
  "last_source_check": "2026-10-05",
  "endpoint_provenance_file": "small-spacecraft-electric-endpoint-provenance.json",
  "provenance_note": "A bounded source-to-claim review found that the NASA summary mixes catalog specifications, component and integrated-system values, flight demonstrations, reconstructed averages, and unresolved endpoints. Read the endpoint ledger before interpreting any range as a measured or universal envelope.",
  "source_locator": {
    "printed_page": 66,
    "pdf_page": 11,
    "table": "Table 4-1: Summary of Propulsion Technologies Surveyed",
    "archive_path": "sources/web/NASA-SmallSat-SOA-2026-In-Space-Propulsion.pdf",
    "archive_sha256": "A5B2AA5843F4B8C09E2EB855F30F4038AD7FF2B588171DEE2755932C8253E81C",
    "accessed_date": "2026-10-01"
  },
  "figure_attribution": "Original chart generated by DMGB Systems from the six technology rows in NASA Table 4-1; no NASA chart artwork is reproduced."
}