EU grants €15M funding for ICARUS inflatable heat shield A European consortium has received €15 million of EU funding to develop an inflatable heat shield designed to recover rocket stages and land spacecraft on Mars. The Inflatable Concept Aeroshell for the Recovery of a re-Usable launcher Stage (ICARUS - because boffins do love a tortured acronym) has received €10 million worth of …
So this is actually a deployment method for a large, flexible heat shield. Anyone know what the actual heat shielding is proposed to be made of as details seem conspicuous by their absence. I assume it's ablative as, even if lower than a conventional heat shield, heating will still be significant.
I don't know about this ICARUS model, but the earlier NASA LOFTID had a flexible head shield of woven silicon carbide (spun into fine filaments and then "woven with the same machine we use to make jeans"), under which were "two insulating layers", then the inflatable bit which was covered in "high temperature use silicone adhesive".
https://web.archive.org/web/20230525004458/https://www.nasa.gov/feature/nasa-inflatable-heat-shield-finds-strength-in-flexibility
> I assume it's ablative
Possibly not. Again, from the NASA LOFTID test:
"When the recovery team hauled the aeroshell out of the ocean, they were surprised to find that the outside “looked absolutely pristine,” said John DiNonno, LOFTID chief engineer at NASA Langley. “You would not have known it had a very intense reentry,” he said. In fact, the inflatable structure is in such good condition, it looks like it could be reused and flown again, DiNonno said, but it needs rigorous testing before making such a determination."
https://edition.cnn.com/2022/11/17/world/loftid-heat-shield-nasa-success-scn/index.html
If I recall correctly -and it is a long time since I read up on this- The idea is to create a heatshield that has a larger surface area than the re-entering spacecraft would normally have.
Since Acceleration is Force / Mass and Force is Pressure x Area, Having a large Area / Mass means that it is possible to decelerate at the same rate with less pressure, meaning that a meaningful desceleration can start higher up in the atmosphere, where said atmosphere is thinner, and thus the pressure heating effect is lower. This may let you get away with less heatshiels mass / problems.
Note that Mr. Bezos ballistic dildo does not need much in the way of heat-shielding for the same reason.
Most heating happens in the viscus fluid surrounding the re-entering spacecraft. Fortunately the object quickly falls away from the hot air. Simply making the craft go slower allows more time for heat transfer from the fluid to the object, but having a bigger object means that the heat is generated in a larger volume of the viscus fluid, which consequently is not as hot.
"So this is actually a deployment method for a large, flexible heat shield. Anyone know what the actual heat shielding is proposed to be made of as details seem conspicuous by their absence."
There was a small aerospace startup in Mojave, CA some years ago that was working on this and has since closed and I believe there was another firm that had done some limited testing. It's not a new concept. I expect it would need to be ablative since current heat shield tiles are rigid ceramic.
Why? The concept has already been successfully tested by NASA, see linked articles elsewhere in the comments. Note, that's "tested" as in, actually hauled into orbit and experienced an actual, real-life reentry, not just "tested" as in "worked in the lab".
Just because something is inflateable, doesn't mean it cannot be made of materials that can withstand extreme temperatures.
It is possible that the inflatable part of the assembly (coated on silicone adhesive in the successful NASA test) doesn't get any hotter than 450 deg C. I'm basing this on the info found below, that silicone products becomes brittle at around 300 deg C, and autocombust at around 450 deg C - at which point it becomes silicon dioxide, a white powder with insulating properties.
The information below is for standard industrial uses of silicone formulations. I don't know if clever chemists have tricks for increasing the maximum temperature silicones can withstand for extreme applications.
https://www.vikingextrusions.co.uk/blog/silicone-rubber-temperature/#:~:text=Silicone%20does%20not%20have%20a,temperatures%20of%20over%20300%20C.
I know, right? After all, we all know they can't go to space (wouldn't get past the dome), and also, why a heat shield? Everybody knows the higher you go, the colder it gets. And now the reptilian leaders want to sell us using an inflatable rubber dingy to use as a heat shield. It's obviously a scam to hide the secret colonies on the backside of the moon. They should rather spend that money in making free energy available to everybody.
(Just to be sure: /s.)
The original parachutes were circular and only had holes in the centre after a suggestion that they would be more stable if acting like a funnel. Now we have highly controllable 'square' parachutes which are so easily steerable that we no longer have competitions as any competent parachutist can land with one foot on a target disc the size of a dinner plate.
The image shows an inflatable version of a 'standard' shaped heat shield, but if inflatable is a genuine option, then something that is a different shape and maybe even has 'holes' in it to direct airflow could be interesting.
See: https://en.wikipedia.org/wiki/Parachuting#:~:text=The%20first%20parachute%20jump%20in,Garnerin%20above%20Parc%20Monceau%2C%20Paris.
https://en.wikipedia.org/wiki/Parafoil
https://reddevilsonline.com
> It's a relatively simple concept. Rather than carry a hefty rigid heat shield spacecraft and rocket stages could carry an inflatable heat shield deployed from a compact container to permit components to be safely returned to Earth, or land on other planets.
This inflatable heat shield will be heavier and bulkier than existing heat shields. The only use case for an inflatable heat shield is on Mars.
It might change the re-entry capsule a lot.
I rather assume that the conical shape is to keep the sides protected by the back. It is about the worst shape for usable space. A big inflatable shield would allow a much bigger vehicle to reenter without having to do it side on, covered in tiles.
You need a nose cone on a rocket. A cone-shaped capsule is ideal for launch and reentry.
You could argue that for a non-uniform craft, a wide inflatable shield makes more sense, but it has nothing to do with size.
You won't get around having to deal with a lot of heat. Even more heat on a wide inflatable shield. The heat has to be dumped somewhere, if not in ablative material, of which you would need even more of on a wide shield because of safety margins. The whole concept is also more risky - have you seen how often panels and chutes fail to deploy? Any moving parts are a risk. Assuming someone even tries, an inflatable heat shield for reentry on Earth is entirely impractical.
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