
SpaceX and Boeing Still Need a Parachute That Always Works - n0pe_p0pe
https://www.wired.com/story/spacex-and-boeing-still-need-a-parachute-that-always-works/
======
Robotbeat
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
> _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?

~~~
Robotbeat
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)

~~~
joezydeco
Did Shuttle use similar chutes, or were those simpler drag chutes for braking?

~~~
hollerith
(Like the F-22 and F-35 do) The Shuttle did aerodynamic braking, which is sort
of like using the whole vehicle as a parachute, which reduced the speed at
which it had to resort to its chute, enabling the chute to be much smaller
than it would otherwise have been:

[https://en.wikipedia.org/wiki/Aerobraking#Aerodynamic_brakin...](https://en.wikipedia.org/wiki/Aerobraking#Aerodynamic_braking)

But even if it didn't do that, it would need a much smaller chute than a
capsule of the same weight because gliding greatly increases distance traveled
through the atmosphere, which enables the vehicle to bleed off a lot more
kinetic energy as drag.

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arijun
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.

~~~
mitchty
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.

~~~
waiseristy
SpaceX has no plans to send Dragon to mars

~~~
gpm
SpaceX had plans to send Dragon to mars, that were cancelled at about the same
time propulsive landing was cancelled for commercial crew. It's likely that
cancelling it for commercial crew also cancelled the mars plans.

~~~
waiseristy
I think they cancelled it because it was a hair brained scheme from the get
go. You need a lot of juice to not only land on mars, but then to propulse
back off of it.

~~~
lightedman
If propulsive landing was a harebrained scheme, we'd have never had the lunar
landings.

~~~
vkou
It takes ~3,000 m/s of dV to slow down, and do a powered landing on the Moon.

It takes takes ~6.400 m/s of dV to slow down, and do a powered landing on
Mars.

Thanks to the tyranny of the rocket equation, it takes ~5x more fuel to do a
powered landing on Mars, than it does on the Moon. For the _entire mission_.
That's five Saturn V rockets, if you want to get a similar payload to Mars and
back.

Shaving most of the dV requirements of the 'land on Mars' leg of the journey
will reduce that requirement, from ~5x to ~2x.

~~~
gpm
As I understand the numbers something like 99.9% of that 6400 m/s dV is done
via aerobreaking. Which makes it actually much easier to land on mars than on
the moon energy wise.

The falcon heavy and dragon were almost definitely up to the task, given that
SpaceX was for a short period of time actively looking for customers.

Source on the 99.9% is this talk (about starship, but I doubt red dragon would
have been substantially different in terms of delta v):
[https://www.youtube.com/watch?v=bysu8XN5OfY](https://www.youtube.com/watch?v=bysu8XN5OfY)

~~~
Tuna-Fish
>99% is possible for the Starship because it has a lot of pitch control, and
can fly a trajectory in the atmosphere where it maximizes lift for as long as
it can.

A capsule doing a simpler landing generally needs to get rid of about 400m/s
using other methods, based on NASA's past missions.

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lightedman
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.

~~~
zlsa
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.

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colebowl
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.

~~~
zlsa
SpaceX originally planned to develop a [propulsive landing
system]([https://youtu.be/Cf_-g3UWQ04?t=90](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](https://en.wikipedia.org/wiki/SpaceX_Red_Dragon)),
a plan to send uncrewed Dragons to the surface of Mars, along with it.)

~~~
DuskStar
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?

~~~
cameldrv
It seems to me that the parachute(s) you need for LES wouldn't need to be as
complex and capable as landing parachutes.

The LES parachute(s) will be firing at quite low speeds, so they don't need to
be too strong. The LES parachute(s) also don't need to be nearly as reliable
or give nearly as soft a landing.

Ejection seats in combat aircraft show the same tradeoff -- it's considered
acceptable to have ejection seats that fail sometimes and sometimes cause a
landing injury. Hopefully you never have to use it, and so even if it fails or
injures you say 10% of the time, it's much better than certain death in a pad
explosion or similar.

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

~~~
JaggedJax
"Fly safe"

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tropo
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](https://en.wikipedia.org/wiki/Ballute)

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stanmancan
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?

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xigency
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.

~~~
GhettoMaestro
> 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
Using old tech is why Boeing lost space though.

~~~
GhettoMaestro
"Lost" space? I'm not following you. Unless you're referring to how up-start
SpaceX has dominated the launch industry in the past 5 to 10 years?

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

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shmerl
_> 600 mph_

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

~~~
kawfey
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.

~~~
catalogia
> _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.

~~~
shmerl
Volume effort went well indeed. What's still lagging behind especially are
temperature, distance and speed units. Lot's of people are still not
comfortable when you are trying to use metric for them. Which probably only
highlights that there should be a stronger push to use them.

Also, 24H time system is something people often don't get, and only know about
it as "military time", due to army actually using it.

~~~
catalogia
I think temperature is easily the most alien to Americans. Metric distances
probably aren't quite as well understood as metric volumes, but I'd wager that
knowledge only trails by a little. The rough equivalence between a yard and a
meter is widely know by Americans, as is the rough equivalence between
100km/hr and 60mph (helpfully, American speedometers all provide this
education.)

~~~
jcranmer
The distances you cite are pretty much the only ones (well, 2.54cm = 1 in as
well) that are likely to be well-known. Yards are just not a heavily-used
unit, people prefer 10s or 100s of feet instead of using yards. So when you go
from tens to hundreds of meters, there is going to be no intuition about what
kind of distance that actually is, and you have to mental math your way to
familiar units of 100s of feet or quarter/half miles.

~~~
catalogia
Meters to feet is easy, it's _roughly_ just x3. Yards _may_ not be common
(yards are certainly common in sports, and sports are very popular), but three
feet to the yard is definitely commonly known. Centimeters might be harder,
but in my experience Americans suck at estimating inches too, one American's
_" half an inch away"_ is another American's _" two inches away."_ And the
average American off the street would be hopeless if asked how many feet are
in a mile. They'd actually have a better chance of giving you a
kilometer->feet conversion than miles->feet. At least, I certainly would
(without looking it up: 1 kilometer = 1000 meters ~= 1000 yards = 3000 feet,
+10% fudge, approximately 3300 feet to the kilometer.)

Anyway, my point in all of this is that if a pop-sci publication like Wired
uses units like kilometers, it is unlikely that their American readers will be
confused. They'll probably walk away from such an article with a casual
understanding of the subject that is reasonably close to the casual
understanding they'd have if the article used miles instead.

