{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "nasa-fpse-references",
 "name": "NASA and Sunpower free-piston Stirling references (public domain) and design numbers",
 "kind": "list",
 "category": "Stirling engines",
 "group": "Guide",
 "year": null,
 "question": "Where are the NASA free-piston Stirling engine design reports and what are the key numbers?",
 "tags": [
  "nasa",
  "free piston",
  "reference",
  "asrg",
  "sunpower",
  "ntrs",
  "stirling",
  "free piston",
  "long earth society",
  "list",
  "guide"
 ],
 "aliases": [
  "nasa stirling engine design",
  "asrg stirling convertor",
  "re-1000 stirling",
  "free piston stirling papers",
  "ntrs stirling",
  "stirling convertor efficiency",
  "sunpower stirling"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": true,
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 "url": "https://xemstudio.com/objects/nasa-fpse-references/",
 "sheet_txt": "https://xemstudio.com/objects/nasa-fpse-references/sheet.txt",
 "sheet": {
  "basis": "NASA Technical Reports Server (NTRS): US Government works are public domain. Headline numbers from the published convertor papers (ASRG, GPHS-ESP, TDC, RE-1000, Sunpower EE-35 / Microgen); hobby-scale rules from Urieli / Berchowitz",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Where the real designs are: NTRS (ntrs.nasa.gov) hosts decades of free-piston Stirling work: the Sunpower RE-1000 test engine (1 kW, 1980s, the best-documented FPSE: dimensions, pressures, strokes, phase angles all published), the Stirling Technology Co. 55 W TDC, the Sunpower ASC/ASRG convertors (80 We class, 102 Hz, helium at 3.5 MPa, 850 °C hot end, flexure suspended, 14+ years on test), Glenn's flexure fatigue and life-test reports, and the thermoacoustic (TASHE) work. Search NTRS for 'free-piston Stirling', 'ASRG', 'RE-1000', 'flexure bearing', 'linear alternator'.",
   "Representative numbers: RE-1000: 57 mm bore, 1 kW, 30 Hz, 7 MPa helium, displacer on a gas spring, piston on a gas spring + dashpot load. ASC-E2: ~80 We, 102 Hz, 3.5 MPa He, piston stroke ~5 mm, hot end 850 °C, cold 90 °C, 38% convertor efficiency, flexure-suspended displacer and piston. GPHS-ESP / SRG110: 55 We, 80 Hz. Microgen (Sunpower-derived) domestic CHP: 1 kWe, 50 Hz, helium.",
   "Why it matters at hobby scale: the same physics scales down (resonance, clearance seals, flexures, linear alternator), only the pressure and frequency drop: air at 1 bar, 10–20 Hz, 0.1–2 W. The parts on this shelf (flexures, alternator kit, free-piston core, regenerator media, tri-clamp vessel) are the hobby-scale translation of the ASRG parts list.",
   "Open design tools: Urieli's Stirling cycle machine analysis (ideal adiabatic + simple models, free online); Sage (commercial, used by NASA); Berchowitz & Urieli 'Stirling Cycle Engine Analysis' (1984) is the standard text; Walker 'Stirling Engines' (1980); Senft 'An Introduction to Low Temperature Differential Stirling Engines' for the can-engine end.",
   "Nothing here is NASA's CAD (none is public); the dimensions quoted are from the papers."
  ],
  "table": {
   "columns": [
    "machine",
    "power",
    "freq_hz",
    "pressure",
    "hot_c",
    "suspension",
    "ntrs_search"
   ],
   "rows": [
    [
     "Sunpower RE-1000",
     "1 kW",
     30,
     "7 MPa He",
     600,
     "gas springs",
     "RE-1000 free-piston"
    ],
    [
     "STC 55 W TDC",
     "55 We",
     80,
     "2.5 MPa He",
     650,
     "flexures",
     "Technology Demonstration Convertor"
    ],
    [
     "Sunpower ASC-E2 (ASRG)",
     "80 We",
     102,
     "3.5 MPa He",
     850,
     "flexures",
     "Advanced Stirling Convertor"
    ],
    [
     "Microgen (Sunpower)",
     "1 kWe",
     50,
     "He",
     500,
     "flexures",
     "Microgen Stirling"
    ],
    [
     "LES hobby free-piston",
     "0.1–2 W",
     "10–20",
     "1 bar air",
     150,
     "printed/steel flexures",
     "—"
    ]
   ]
  }
 },
 "sheet_text": "NASA and Sunpower free-piston Stirling references (public domain) and design numbers — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/nasa-fpse-references/  (CC BY 4.0)\nBasis: NASA Technical Reports Server (NTRS): US Government works are public domain. Headline numbers from the published convertor papers (ASRG, GPHS-ESP, TDC, RE-1000, Sunpower EE-35 / Microgen); hobby-scale rules from Urieli / Berchowitz\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Where the real designs are: NTRS (ntrs.nasa.gov) hosts decades of free-piston Stirling work: the Sunpower RE-1000 test engine (1 kW, 1980s, the best-documented FPSE: dimensions, pressures, strokes, phase angles all published), the Stirling Technology Co. 55 W TDC, the Sunpower ASC/ASRG convertors (80 We class, 102 Hz, helium at 3.5 MPa, 850 °C hot end, flexure suspended, 14+ years on test), Glenn's flexure fatigue and life-test reports, and the thermoacoustic (TASHE) work. Search NTRS for 'free-piston Stirling', 'ASRG', 'RE-1000', 'flexure bearing', 'linear alternator'.\n- Representative numbers: RE-1000: 57 mm bore, 1 kW, 30 Hz, 7 MPa helium, displacer on a gas spring, piston on a gas spring + dashpot load. ASC-E2: ~80 We, 102 Hz, 3.5 MPa He, piston stroke ~5 mm, hot end 850 °C, cold 90 °C, 38% convertor efficiency, flexure-suspended displacer and piston. GPHS-ESP / SRG110: 55 We, 80 Hz. Microgen (Sunpower-derived) domestic CHP: 1 kWe, 50 Hz, helium.\n- Why it matters at hobby scale: the same physics scales down (resonance, clearance seals, flexures, linear alternator), only the pressure and frequency drop: air at 1 bar, 10–20 Hz, 0.1–2 W. The parts on this shelf (flexures, alternator kit, free-piston core, regenerator media, tri-clamp vessel) are the hobby-scale translation of the ASRG parts list.\n- Open design tools: Urieli's Stirling cycle machine analysis (ideal adiabatic + simple models, free online); Sage (commercial, used by NASA); Berchowitz & Urieli 'Stirling Cycle Engine Analysis' (1984) is the standard text; Walker 'Stirling Engines' (1980); Senft 'An Introduction to Low Temperature Differential Stirling Engines' for the can-engine end.\n- Nothing here is NASA's CAD (none is public); the dimensions quoted are from the papers.\n\nmachine  power  freq_hz  pressure  hot_c  suspension  ntrs_search\nSunpower RE-1000  1 kW  30  7 MPa He  600  gas springs  RE-1000 free-piston\nSTC 55 W TDC  55 We  80  2.5 MPa He  650  flexures  Technology Demonstration Convertor\nSunpower ASC-E2 (ASRG)  80 We  102  3.5 MPa He  850  flexures  Advanced Stirling Convertor\nMicrogen (Sunpower)  1 kWe  50  He  500  flexures  Microgen Stirling\nLES hobby free-piston  0.1–2 W  10–20  1 bar air  150  printed/steel flexures  —\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- NASA (NTRS, public domain): Advanced Stirling Convertor (ASC) development (2010) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=Advanced Stirling Convertor\n- NASA (NTRS, public domain): RE-1000 free-piston Stirling engine sensitivity test results (1986) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=RE-1000\n- NASA (NTRS, public domain): Stirling convertor flexure fatigue testing (2008) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=flexure fatigue Stirling\n- NASA (NTRS, public domain): Thermoacoustic Stirling heat engine (TASHE) for space power (2004) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=thermoacoustic Stirling\n- Wikipedia: Advanced Stirling radioisotope generator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Advanced_Stirling_radioisotope_generator\n- Wikipedia: Stirling radioisotope generator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_radioisotope_generator\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nXem Studio scan: not planned; the official CAD above covers it.\nAPI: https://xemstudio.com/api/geometry?object=nasa-fpse-references\n",
 "sources": [
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "Advanced Stirling Convertor (ASC) development (2010)",
   "url": "https://ntrs.nasa.gov/search?q=Advanced Stirling Convertor",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "RE-1000 free-piston Stirling engine sensitivity test results (1986)",
   "url": "https://ntrs.nasa.gov/search?q=RE-1000",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "Stirling convertor flexure fatigue testing (2008)",
   "url": "https://ntrs.nasa.gov/search?q=flexure fatigue Stirling",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "Thermoacoustic Stirling heat engine (TASHE) for space power (2004)",
   "url": "https://ntrs.nasa.gov/search?q=thermoacoustic Stirling",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Advanced Stirling radioisotope generator",
   "url": "https://en.wikipedia.org/wiki/Advanced_Stirling_radioisotope_generator",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Stirling radioisotope generator",
   "url": "https://en.wikipedia.org/wiki/Stirling_radioisotope_generator",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
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 "related": [
  "free-piston-core",
  "spiral-flexure-bearings",
  "linear-alternator-kit",
  "regenerator-and-heat-materials",
  "tri-clamp-spool"
 ],
 "faq": [
  {
   "q": "Are NASA's Stirling engine designs public?",
   "a": "The reports are (US Government work, public domain, on NTRS): dimensions, operating points, test data and analysis for RE-1000, TDC, ASC/ASRG. The CAD and the Sunpower-proprietary details are not."
  },
  {
   "q": "What frequency and pressure do NASA Stirling convertors run at?",
   "a": "ASC/ASRG: about 102 Hz on helium at 3.5 MPa with an 850 °C hot end; RE-1000: 30 Hz at 7 MPa; the 55 W TDC: 80 Hz at 2.5 MPa."
  },
  {
   "q": "Can I build a free-piston Stirling engine at home?",
   "a": "Yes at air pressure and 10–20 Hz: the physics is the same, the output is 0.1–2 W. The hard parts are the clearance seal (lap or use glass/graphite) and tuning the two resonances; everything else is on this shelf."
  }
 ],
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 "markdown": "https://xemstudio.com/objects/nasa-fpse-references/index.md"
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