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Cryo Aerogel, MLI, or Foam: Choosing Cryogenic and Space Insulation Materials
Cryogenic insulation is judged by where it is weakest, and the weak points are never the straight runs. They are the fittings, supports, seams, and closeouts, where heat leaks in, ice grows, and vapor drives. The thermal model assumes a continuous envelope; only the fitted detail parts deliver it. The families on the H-O cryogenic and space page sort by the thermal job and the vapor-and-vacuum job at once, and this guide walks each one by the decision it wins, with methods named by designation.
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Cryogenic failures concentrate at the interruptions
Cryogenic insulation is judged by where it is weakest, and the weak points are not the straight runs. They are the fittings, supports, seams, and closeouts, the places flat-roll insulation gives up, where heat leaks in, ice grows, and vapor drives. The thermal model assumes continuity; the parts list has to deliver it, which means the fitted, die-cut detail parts are the system, not accessories.
So the families on the H-O cryogenic and space page sort by two jobs at once: the steady-state thermal job and the vapor-and-vacuum job that decides whether the insulation survives chill-down and ascent. This guide walks them by the decision each one wins, with methods named by designation: ASTM C177 for thermal conductivity, ASTM C1728 for flexible aerogel specification, ASTM C740 as the evacuated-insulation framing, ASTM E595 for outgassing, and ASTM D1056 for the foam compression behavior.
Per-grade values are the maker-TDS figures cited on the parent page.
The aerogel blanket grades: pick by temperature and dew point
Cryogenic-class aerogel for the cold lines
Propellant feedlines, tank exteriors, and cryogenic transfer lines want a cryogenic-class flexible aerogel: ArmaGel XGC from the cryogenic aerogel family is engineered for cryogenic-class service, conductivity per ASTM C177 and specified per ASTM C1728 flexible-aerogel class methods on its TDS. Where the line runs sub-ambient in humid pad air, Cryogel Z adds the vapor-control behavior the cold-and-humid case needs, because below the dew point the vapor layer governs as much as the thermal layer.
High-temperature aerogel for the hot adjacencies
Cryogenic systems are not uniformly cold: a launch vehicle carries hot gas lines, engine adjacencies, and ground-support runs beside the cryogenic plumbing. Pyrogel XTE, rated for service to 650 °C per the maker's data, takes those hot adjacencies, so one converted parts package can carry both ends of the temperature range. Read the grade against the line temperature, not the system name.
The film and membrane layer: MLI and venting
Multilayer insulation is a system H-O supplies the converted detail parts for, not a finished blanket: Kapton and Apical polyimide film serves as the radiation-shield and substrate film, and ePTFE membrane patches venting openings where particulate control matters.
The venting itself is a converted feature, because an MLI blanket that passed every ground test will balloon during ascent depressurization if trapped air has nowhere to go: vent paths, perforation patterns, and edge vents are die-cut to the ascent profile and drawn on the blanket like any other dimension.
The evacuated-insulation framing is ASTM C740 by designation; the vent geometry is the program's to specify and ours to cut. AeroZero thin polymer aerogel film insulates electronics-adjacent and optics-adjacent layers where millimeters decide.
The thermal and foam layers
Where a grounded conductive path is wanted, NeoGraf flexible graphite carries it, with outgassing screened per grade where the bay is contamination-sensitive.
The foams do the spacer and interface job: SOLIMIDE polyimide foam stays resilient across the temperature swing and is the workhorse for interface spacers and expansion-joint infills, while BISCO HT and BF silicone foam handles the cryo-adjacent gaskets and contact pads with compression behavior per ASTM D1056.
The spacer choice is dominated by one cryogenic fact: a part dimensioned warm goes loose cold, so resilient materials and a cold-case gap stack matter more than the ambient fit.
Cryogenic and Space Families by the Job They Win
| Family | Job | Vapor / vacuum role | Temperature position | Where it lives |
|---|---|---|---|---|
| ArmaGel XGC / Cryogel Z | Cryo blanket | Cryogel Z vapor-control | Cryogenic-class per TDS | Feedlines, tank exteriors, transfer lines |
| Pyrogel XTE | Hot-adjacency blanket | n/a | To 650 °C per maker data | Hot gas lines, engine adjacencies, GSE |
| Kapton / Apical / ePTFE membrane | MLI film / vent | Vent geometry | Per grade TDS | MLI substrates, vent patches, spacers |
| NeoGraf graphite | Thermal path | Screen E595 per grade | Per grade TDS | Grounded conductive thermal layers |
| SOLIMIDE / BISCO foam | Spacer / gasket | Resilient cold | Across the swing per TDS | Interface spacers, expansion joints, gaskets |
Illustrative and relative only; confirm each grade on its current technical data sheet. Thermal per ASTM C177 / C1728; evacuated framing per ASTM C740; outgassing per ASTM E595 per grade; space-flight qualification belongs to the program.
Two rules that sort the page
First, the detail parts are the deliverable: a thermal model assumes a continuous envelope, and only fitted, die-cut valve covers, flange collars, contour saddles, and support spacers, kitted per spool with engineered overlaps, actually deliver it. Second, below the dew point the vapor layer governs as much as the thermal layer: a chilled line with ordinary seam discipline grows ice under its insulation until the jacket splits, so seam sealing, overlap geometry, and every penetration are vapor details on the drawing, not just thermal ones.
Outgassing, finally, is screened on the construction as built, base plus adhesive plus liner, per ASTM E595 against the program's limits.
How H-O Products helps
H-O Products is a precision die-cut converter, not a raw-material producer. We take cryogenic and high-temperature aerogel blanket, polyimide film, ePTFE membrane, flexible graphite, and polyimide and silicone foam stock from the material manufacturers and die-cut, knife-cut, laminate, and kit it to your drawing, with material traceability and lot-code TDS records under our ISO 9001:2015 certified quality management system in Winsted, Connecticut.
We recommend a family and grade direction from your service-temperature band, outgassing budget, thermal-cycling and contraction behavior, vacuum and venting needs, and integration method, and grade-level values are confirmed against the manufacturer's current TDS. Thermal design and space-flight qualification stay with the program.
Frequently asked questions
What insulation is used on cryogenic propellant lines?
A fitted aerogel-blanket system, not a wrap. Cryogenic-class flexible aerogel such as ArmaGel XGC carries the feedlines and tank exteriors, with conductivity per ASTM C177 and specification per ASTM C1728 on the TDS, and Cryogel Z is chosen where a sub-ambient line in humid air needs vapor-control behavior. The thermal budget is kept or lost at the interruptions, so the deliverable is the fitted detail parts, valve covers, flange collars, and contour saddles, kitted per spool with engineered overlaps.
What is MLI, and what parts of it does a converter supply?
Multilayer insulation is a radiation-control system of thin reflective films and spacers used in vacuum. H-O supplies the converted detail parts, not a finished flight blanket: polyimide film substrates, die-cut vent perforations and edge vents, and ePTFE-patched openings where particulate control matters. The venting is a converted feature because an MLI blanket with no vent path balloons during ascent depressurization. The evacuated-insulation framing is ASTM C740 by designation; the vent geometry is the program's to specify and ours to cut.
Why does ice form on insulated cryogenic lines?
Because below the dew point the vapor layer governs as much as the thermal layer. A chilled line wrapped with a high-performance blanket but ordinary seam discipline lets humid air reach the cold surface through the seams; vapor drives toward the cold metal and the line grows ice under its insulation until the jacket splits. The fix is to specify a sub-ambient grade with vapor-control behavior per the TDS and to detail seam sealing, overlap geometry, and every penetration as a vapor detail on the drawing.
What do percent TML and percent CVCM mean for a space material?
They are the outgassing screening numbers from ASTM E595: total mass loss and collected volatile condensable material, reported grade by grade. They matter because a material with flight heritage can still fog a cold optical surface if the converted construction, base material plus adhesive plus liner residue, was never screened as built. Screen the exact construction per E595 against the program's contamination limits, which are framed by the mission's materials-and-processes requirements such as NASA-STD-6016 by designation.
Does H-O perform thermal design or hold space-flight qualification?
No. H-O converts the documented materials into the fitted detail parts and kits a cryogenic or space system needs, to the drawing, with material traceability and lot-code TDS records. The thermal design that sizes the insulation, the vent geometry sized to the ascent profile, the outgassing limits, and space-flight qualification belong to the program and its test houses. Our role is bounded: die-cut, knife-cut, laminate, and kit the aerogel, film, membrane, graphite, and foam to your drawing, repeatably.
Get a cryogenic insulation recommendation
Tell us the service-temperature band, the outgassing budget, the thermal-cycling and contraction behavior, the vacuum and venting needs, and the integration method, and we will recommend a family and grade direction and quote die-cut detail parts to your drawing.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
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Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- ASTM C177 (steady-state thermal conductivity); ASTM C1728 (flexible aerogel insulation class methods).
- ASTM C740 (evacuated reflective insulation framing for MLI; vent geometry is the program's to specify).
- ASTM E595 (outgassing, total mass loss and collected volatile condensable material, per grade); NASA-STD-6016 (materials-and-processes framing, by designation).
- ASTM D1056 (compression behavior of the polyimide and silicone foam spacers and gaskets).
- Manufacturer technical data sheets for the cryogenic and high-temperature aerogel, polyimide film, ePTFE membrane, flexible graphite, and foam grades named on the parent application page.
This article summarizes insulation material-selection principles for cryogenic and space systems using the families and published test methods cited on the parent application page. Comparisons are qualitative; per-grade values quoted are maker-TDS figures and must be confirmed on the manufacturer's current technical data sheet at your temperature, vacuum, and installed condition. Standards (ASTM, NASA-STD) are cited by designation for context, not as a claim of qualification.
H-O is a precision die-cut converter, not a raw-material producer, and does not perform thermal design, certify materials, or hold space-flight qualification; those belong to the program and its test houses.