For technology that involves complex engineering issues, standardization and specialization is extremely helpful. If I want to design a complex ASIC IC I don't design it from scratch, I just drag-and-drop thoroughly tested and characterized blocks from another company's standard cell library who specializes in this, and If I design a fancy cell phone I (usually) open up catalogs and order thoroughly tested and characterized ICs again made by other companies who specialize in supplying these. If I require a new IC then I still reach for those standard cell libraries.

If I'm going to visit a neutron star, I don't build my ship from scratch, I simply order a thoroughly tested and characterized general products hull built by a species who specializes in supplying these.

Recently both of the crew capsules being designed for NASA were either delayed or threatened with delays due to parachute issues, and I have just read that

Apparently ESA has had major problems in getting the parachutes right

I'm sure I can find other examples in the last several years where spaceflight mission schedules were threatened by parachute failures.

I understand that every spacecraft is different and therefore the ideal parachute will need to be different, but here in 2020 why can't there be worldwide standard spacecraft parachutes in small, medium and large?

Is it "not invented here" thinking or otherwise a good idea but not likely to happen, or are the differences between mission demands and atmospheric density and velocity at deploy time so different that each spacecraft demands a totally new parachute despite the statistically significant dangers of mission delays due to unanticipated failures during final testing?

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    $\begingroup$ I'm no authority, but I'm guessing that it's the reliable deployment of the chute from its stowed position, in the complex aerodynamic environment around a capsule, rather than the dimensions and materials of the chute itself, that are challenging to design, and those are necessarily specific to the spacecraft. $\endgroup$ – Russell Borogove Feb 26 at 0:45
  • $\begingroup$ We don't know how to analyze them. Those things you list are simple in comparison! :) finance.yahoo.com/news/… $\endgroup$ – Organic Marble Feb 26 at 1:07
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    $\begingroup$ I'm just thinking that it would be better if the most reliable few parachute designs in the world became standard and spacecraft where then designed around them, like the way that the 737 Max was designed around those bigger engines. Oh wait, I just shot myself in the foot there, didn't I. ;-) $\endgroup$ – uhoh Feb 26 at 1:10
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    $\begingroup$ When rigging heavy-cargo parachute sets, you (used to) use a manual full of tables. You go in with speed & drop, make an altitude correction, make an aircraft type correction to get a “sequence factor” which you combine with weight to select number & type of chutes. You then go through again to rigging length, open delay, etc. Every drop is different. Most go ok. $\endgroup$ – Bob Jacobsen Feb 26 at 2:37

When you need to slow down and soft-land a spacecraft, you need to consider

  1. How heavy is the craft?
  2. How fast will it be going when you try to stop?
  3. Will anything else be supplying stopping power? (i.e. a rocket motor above the payload)
  4. How heavy is the gear doing the stopping? (has to be offset with fuel)

In 2015 NASA ripped a large supersonic parachute

The 100-foot-wide (30 meters) parachute — the biggest such chute ever deployed — unfurled well and apparently inflated fully, or nearly fully, Monday (June 8) before being ruptured by the fast-rushing air during the second flight test of NASA's Low-Density Supersonic Decelerator (LDSD) project.

Of interest is this quote

"On this project, we're pushing the limits of our technologies, our engineering and our understanding of aerodynamic decelerators," Clark added. "This year, the physics of supersonic parachutes pushed back on us."

From the linked article about the ESA parachute woes

ESA parachute

Europe's 35-meter parachute in a 2018 test in Sweden. It will be the largest ever on Mars.

You'll note there's a 5M difference in the two parachutes. Why? NASA elaborates on that in general on another project (emphasis mine)

The design of the parachute is driven by "loads" (the forces the parachute experiences as it fully inflates). Loads are calculated by using atmospheric density, velocity, parachute drag area, and mass. The 2003 parachute design is part of a long-term Mars parachute technology development effort and is based on the designs and experience of the Viking and Pathfinder missions. The parachute for this mission is 40% larger than Pathfinder's because the largest load for the Mars Exploration Rover is between 18,000 and 19,000 pounds (80,100 - 84,600 N*) when the parachute fully inflates. By comparison, Pathfinder's inflation loads were approximately 8,000 pounds (35,600 N*).

Given that we're custom building spacecraft, it makes sense that agencies would custom make parachutes. If you try to make a one-size-fits-all parachute, you're limiting the size of spacecraft, and potentially over-sizing the parachute (and adding needless weight) to smaller craft. I do expect that, as we gain more experience building them, there will be more standardization, but for now, spacecraft are still esoteric enough to warrant custom parachutes.

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    $\begingroup$ and yet many other components (e.g. thrusters, communications boxes) designs are reused over and over, either exactly or with only small modifications, so I'm still not sure why "Given that we're custom building spacecraft, it makes sense that agencies would custom make X" is true when X = parachutes but not several other components. I can guess it's because for example in the case of thrusters, even though different spacecraft may be different mass or have different moments of inertia, the thrusters can be moved around and their impulse is adjustable, and for radios it doesn't really matter. $\endgroup$ – uhoh Feb 26 at 3:33
  • $\begingroup$ "Given that we're custom building spacecraft, it makes sense that agencies would custom make parachutes" -- it may be worth mentioning that for 'cheaper' missions existing craft and EDL systems are reused with different instruments -- but yes, the problem is we want to get more done, and miniaturisation isn't giving us what we need, so we need bigger EDL systems $\endgroup$ – JCRM Feb 26 at 7:07
  • $\begingroup$ Not to mention atmospheric conditions which can differ by planet and location/season. Also size and weight restrictions and finally different risk profiles. $\endgroup$ – eckes Feb 28 at 5:17

Let's go back a bit farther. The first human-rated parachutes managed to keep humans from dying or being horribly injured upon landing (from an airplane) -- most of the time. A certain damage rate was acceptable for military operations.

Jump forward a few decades, and the first sport-chutes that were both steerable and capable of achieving much lower terminal speeds came out. They were a massive redesign compared with the originals.

None of those were designed to operate in windspeeds anywhere near Mach 1. So another complete redesign was necessary to deal with falling rocks, aka Mercury/Gemini/Apollo capsules.

But all those rocks were designed to land on water, as opposed to the Soviet capsules whose parachutes had to soft-land on dry ground. Yet another set of design constraints.

And now we have SpaceX recovering fairings from significant altitudes, but with some steering capability required to reach Ms.Chief and Ms. Tree.

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  • $\begingroup$ I'm not sure I can see how this directly answers the title "What is it about parachutes that makes people always want to 're-invent the wheel'?" or the last few sentences of the body of the question. You've included some history but can you include a "because" somehow? Thanks! $\endgroup$ – uhoh Feb 26 at 21:54
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    $\begingroup$ For example the last paragraph in this answer wraps it up and draws a conclusion. $\endgroup$ – uhoh Feb 26 at 22:20

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