SpaceX and Boeing Still Need a Parachute That Always Works

https://www.wired.com/story/spacex-and-boeing-still-need-a-parachute-that-always-works/

by n0pe_p0pe • 7 years ago

107 73 7 years ago

wired.com

shmerl5• 7 years ago

600 mph

Probably better to use km/h, especially for space related coverage.

kawfey• 7 years ago

Americans don't have an intuitive sense of metric units, and Wired is based in the US and has mostly US readership. I agree with you, and I'll bet the editor also agrees, but they'd probably get FAR more comments to use imperial units because 'merica, if metric was used instead.

ptaipale• 7 years ago

When discussing speed of an object that is landing, m/s might in fact be even better for most of the world.

shmerl5• 7 years ago

That's one of the ways to develop intuitive sense - start using it everywhere. It will never develop if it's not used. Besides, officially US was supposed to switch to metric system anyway, so formally there is nothing wrong with using it and no one should be complaining. Except it takes ages and almost not moving anywhere due to complete apathy from the government about it.

catalogia3• 7 years ago

Americans don't have an intuitive sense of metric units

I don't really believe that. American public schools have been teaching the metric system to middle schoolers for a few decades now. Every American I talk to understands the metric system. In some cases, particularly units of volume, they understand the metric system better than the imperial units (liters are easy, but I can never keep quarts/pints/cups/floz/etc straight in my head.) Coca Cola sells sugar water to Americans in liter-oriented packaging (.5, 1, an 2 liter bottles are ubiquitous), and Americans certainly don't balk at that. They drink it up.

arijun• 7 years ago

It's too bad NASA didn't let SpaceX test propulsive landing with the cargo Dragons. Without that, SpaceX scrapped the feature from the Dragon program as a whole. It seems like they might have been able to get more reliability with that than the parachutes. And even if not, if I was sitting in a capsule that had a history of parachute failures, I'd feel a whole lot safer if there was a backup propulsive system ready to kick in in the event of a chute failure.

mzkply• 7 years ago

They would still have had to work on parachutes because a Pad Abort uses up all the propellant... leading to a parachute landing just off the beach at the Cape.

apendleton• 7 years ago

They didn't scrap it exactly, they just relegated its function to use as an emergency propulsive abort system. But the Dragon 2 still has the super dracos... and one of them exploded, causing the loss of a test vehicle, a few months ago, which has resulted in timeline setbacks to the program. It doesn't seem like reliability has been a walk in the park there either.

waiseristy5• 7 years ago

The super draco didn't explode fyi, it was the fueling system.

mitchty• 7 years ago

Wouldn't dragon need the rockets to land on Mars? Parachutes aren't gonna do jack in Mars atmosphere.

I thought that was the bigger reason for the retro rockets.

waiseristy5• 7 years ago

SpaceX has no plans to send Dragon to mars

maccam94• 7 years ago

SpaceX pivoted to building an entirely new rocket for Mars called Starship.

gambiting• 7 years ago

That's not true, Curiosity used a parachute for part of its landing - it just needs to be pretty large to have an effect in atmosphere so thin:

https://www.space.com/16878-mars-rover-landing-sky-crane-gui...

the_duke• 7 years ago

If I remember correctly, SpaceX totally could have gone for propulsive landing, but opted not to because certification would have been a lot more work.

stetrain• 7 years ago

I think it basically came down to NASA not wanting them to test it on NASA flights.

SpaceX would have had to do their own launches and landings to verify the propulsive landing system, but they wanted to test it out on "production" cargo missions they were already doing for NASA.

hyperion2010• 7 years ago

It seems like the minimal possible complexity of a sheet of fabric is always going to be higher than the minimal complexity of an engine simply because the physics of cloth are much harder to simulate accurate so you will never be able to find all the edge cases. Yes engines are initially more complex to build, but their minimum complexity once they are well understood should be lower -- even with the code needed to run them. You can't exact attach a debugger to the universe.

xigency• 7 years ago

How is the problem and solution different than the parachutes used in early NASA programs like Mercury?

Since the design of Boeing’s parachute system is so similar to NASA’s, the company had to perform fewer tests to demonstrate the system’s safety compared to SpaceX.

This doesn't seem like a good habit for Boeing.

GhettoMaestro2• 7 years ago

This doesn't seem like a good habit for Boeing.

While I like to bang on Boeing for being fucking dumb about 737MAX, the habit of copying an existing well-tested, approved design is something that should NOT be discouraged.

Re-use of existing validated solutions / components leads to faster development cycles and increased agility (financially) . This is achieved by making more critical components COTS (Commercial Off The Shelf - not one-off / custom) and re-usable as self-contained "modules" or "packages".

Reinventing the wheel for reinventing the wheel's sake is in most cases not a good use of resources.

That said, if the original design has issues, my above commentary is invalidated somewhat - you need to modify the design to fix the root cause, which should trigger a fresh round of validation and testing at the original specification levels or greater. And of course, you should always do fully integrated tests, even if all of the components were previously validated and approved. You pretty much always find stuff (maybe only in solution-integrated combination) - I believe that's what happened in this case.

pizzaparty2• 7 years ago

Using old tech is why Boeing lost space though.

bendbro• 7 years ago

I don't think he means existing designs shouldn't be reused. I think he means that you shouldn't lessen testing because you are using an existing designs.

Boeing reused the 737 design to produce the 737 Max; however, because it was a reused design, Boeing did not go through the same certification process or testing that would have been done for a new airplane. Skipping testing because you have a reused design is the bad habit he is referring to.

caconym_• 7 years ago

From a quick Googling, the heaviest Mercury capsule launched weighed 3k lbs, while Crew Dragon is 20k lbs dry. That extra mass makes the problem significantly more complicated.

As for later programs like Apollo that are more comparable, I'm not sure. Maybe they were comfortable with heavier systems or worse safety margins. Also, I expect that working out the parachutes for Apollo was not easy.

gpm4• 7 years ago

Apollo also had parachute issues, e.g. see Apollo 15.

WalterBright2• 7 years ago

This doesn't seem like a good habit for Boeing.

Using pre-existing proven designs for components is essential for building safe systems.

diego• 7 years ago

It sounds like the old-style parachute is not the best solution for this problem, but I'm sure they must have come up with other ideas and ruled them out. Why not hundreds of small parachutes? Why not wings or rotors to stabilize it? I'm curious to know.

SliderUp• 7 years ago

Anything non-fabric would weigh too much. Many smaller parachutes means many more lines, which would weigh too much.

The rocket equation is cruel.

24gttghh• 7 years ago

Smaller parachutes would be larger surface area compared to one large chute also, right? More weight there.

jccooper• 7 years ago

Parachutes were supposed to be easy because they have plenty of heritage and other users. And in spite of the problems they likely still are easier. Any other system would need even more testing.

Robotbeat2• 7 years ago

Interestingly, SpaceX (Dragon), Boeing (Starliner), and NASA/Lockheed (Orion) all use the same supplier/subcontractor for parachutes: Airborne Systems.

Parachutes are hard. They're super complicated. They'll figure it out, but this will always be tough.

namirez• 7 years ago

Parachutes are hard.

I'm surprised to hear this. I've not heard much about parachute failures in Soyuz landings, except Soyus-1 in the 60's. Nasa had a good track record with parachutes too before they started using the space shuttle.

Are there technical challenges unique to SpaceX or Boeing that other systems didn't have to deal with?

Robotbeat2• 7 years ago

Soyuz has a reserve parachute. Also, because Soyuz only has one, large primary chute, you're less likely (by a factor of 3 or 4) to see any failures. And a reliability of 142:143 is not terribly high for a safety-critical system.

No US orbital crew fatalities have ever occurred due to parachute failure, but parachute failure has occurred on at least one of the Apollo missions (Apollo 15). One parachute failure out of 61 parachutes for the US[0] versus one (or two, counting the reserve) parachute failures out of 143 (144) parachutes for Russia/USSR. The statistics here are effectively indistinguishible in any meaningful measure.

The challenge is these are new, pre-operational crewed spaceflight systems being developed from the beginning. New systems ALWAYS have a higher rate of failure for complex things like this, and also because there are not yet actually crew on board, there's a little bit lower level of mission assurance (which I would argue is optimal!). Nothing in particular special about SpaceX or Boeing.

And in many ways, we got lucky that there weren't more parachute-related fatalities. We understand the dynamics significantly better now than in the past.

[0](1 parachute on each Mercury and Gemini mission, 3 parachutes on each Apollo capsule)

madaxe_again• 7 years ago

It’s worth noting that it’s not the parachutes that typically fail, rather, the deployment systems.

You’re packing (by hand) a large area of fabric and cord into a very small volume. You’re coating that fabric and cord with a variety of anti-stick substances, which have to be stable with extreme temperature and radiation levels, and huge vibrations.

Parachutes are deployed in several ways - springs, hydraulics, compressed gas, explosives, drogues, and combinations thereof.

For flight tests, parachutes are typically pre-stressed as though they’ve been to orbit and back. This wasn’t always the case.

So - there’s a lot of surface area to go wrong purely around the problem of getting it to eject and unfurl, before you even start to think about the parachute itself.

hinkley• 7 years ago

supersonic parachutes, in particular, are hard.

They spent a bit of time talking about this on a documentary about a Mars lander. Supersonic wind tunnels are spendy.

lightedman2• 7 years ago

You simply cannot make a parachute that always works. My pal that works at SkyDive Perris has seen plenty of perfectly-packed parachutes fall prey to an errant gust of wind turning the chute inside-out mid-deployment and making it useless, requiring immediate deployment of the backup.

Now imagine this happening under supersonic conditions. Recovery would be almost impossible.

This is why skydivers wear multiple chutes.

zlsa2• 7 years ago

The solution common to Boeing and SpaceX is the same: they have three (Boeing) or four (SpaceX) separate parachutes, each with their own drogue chutes, and they both can handle a single deployment failure without endangering the crew.

ceejayoz• 7 years ago

Now imagine this happening under supersonic conditions.

Seems like even a big gust wouldn't make much difference at supersonic speeds in thin atmosphere.

colebowl• 7 years ago

This may just be conjecture but it's always seemed like they are solving the wrong problem. Why aren't they looking for alternatives to parachutes which to me seem like an archaic way of doing things. In saying that, the number of different maneuvers required in landing the space shuttle definitely shows how hard this problem is.

zlsa2• 7 years ago

SpaceX originally planned to develop a [propulsive landing system](https://youtu.be/Cf_-g3UWQ04?t=90), but this was dropped due to several reasons:

* The additional risks of a relatively untested system * Starship development had begun, which would make Dragon obsolete

Propulsive landing of Dragon was therefore scrapped (and [Red Dragon](https://en.wikipedia.org/wiki/SpaceX_Red_Dragon), a plan to send uncrewed Dragons to the surface of Mars, along with it.)

DuskStar• 7 years ago

Don't forget the biggest reason - the LES system used the same fuel as the propulsive landing system, and they only carried enough for one of the two. Which meant that landings after using the LES would require a parachute, and if you're carrying a parachute with you anyways why not just use it all the time?

skunkworker• 7 years ago

The propulsive landing is still potentially a backup option to a parachute failure in the future.

Q: Are thrusters programmed as backup if chutes fail to deploy properly?

A: Most likely, but this is contingent upon NASA review & approval

https://twitter.com/elonmusk/status/1104510803313487872?lang...

Nasrudith• 7 years ago

The tyranny of the rocket equation mostly - parachutes are light in comparison. They could use a burn to handle the deorbit or a but that would add more mass which requires adding more mass.

The "more modern" alternatives would be heavier and depend upon more systems. Even if dealing with futuristic assumptions like say electromagnetic in atmosphere flight and battery density/reactors good enough to handle reentey braking for a reduction of net reaction mass a parachute would have a place as a backup plan.

WalterBright2• 7 years ago

All that really needs to be recovered are the astronauts. A backup system could be devised where the astronauts bail out and come down on their own parachutes.

stanmancan• 7 years ago

It’s a strange thing. I never expected parachutes to be the hard part when sending people to space. Any idea why this is causing such a headache?

indue• 7 years ago

Apparently the phrase should be "It's not parachute science" since that appears to be more difficult than "rocket science."

JaggedJax• 7 years ago

"Fly safe"

tropo• 7 years ago

Supersonic parachutes are terrible. Notice that supersonic aircraft air intakes involve ramps (F-15, Concorde, XB-70, F-14), shock cones (SR-71, MiG-21), or diverterless supersonic inlet (F-35, FC-1 Xiaolong). Simple round openings, without a central spike, do not work well at all. It's bad news for parachute design before even thinking about the problems of parachute lines and the need to withstand shock waves as the geometry rapidly changes while unfolding.

The right solution is probably the ballute. SpaceX, Rocket Lab, Armadillo Aerospace, and Copenhagen Suborbitals have all been investigating ballutes in recent years.

https://en.wikipedia.org/wiki/Ballute

SpaceX and Boeing Still Need a Parachute That Always Works

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