Pythom Space is Playing with Fire, Attracting the Wrong Sort of Attention

[JackC]

My college rocketry team stumbled across these Pythom morons last year. It's so frustrating as California has strict laws for amateurs (which we follow) and then we have these absolute idiots managing to get away with this.


Video of one of their tests on Jan 12, 2021

Back in January 22, 2021, we marvelled at, "Witness the 1950's approach to safety, the fact that the engine is just a glorified flamethrower without proper combustion, and the atrocious cinematography" and speculated about what laws they were breaking. Some other funny things to consider is they released this video thinking it made them look good under the original title, "Hell Yeah!" Noteworthy too is loading homemade WFNA on a ladder with only a single respirator to be seen.

We also found: https://www.pythomspace.com/team/ were looking at the personnel of the time, they were all thrill-seekers. At that time, they had a single mechanical engineer and no chemists.

We have photos of them making the nitric acid. Witness the lack of PPE while working with concentrated sulfuric acid:

They got their initial 500k investment from a venture group known as "Space Cowboys". Yes, I am not making this up.

Afterwards, we forgot about them for a bit and I assumed they got shut down or something and then we get this latest video from March and it seems that they haven't learned a thing.

Edit: Some other things to note. The title of the video states it was in 2021, while the video card says 2020. I think it was actually 2021.

I don't hold this against them, but I think it's a little funny that they counted down 5...3...4...2...1...

Space Cowboys?! They had to rip off the title of an Eastwood/Lee Jones movie rather than come up with something original.

 

[jqavins]

Easier way to clean carboys for acid use is to wash with hot water and dawn, continuous rinse with hot water for 3 minutes. Then rinse with room temp piranha solution. Then rinse again.

They say a little knowledge is a dangerous thing, and a little knowledge is just what I've got. If you're going to end with piranha solution, why the Dawn and full three minutes? Once the piranha hits it, wouldn't a good hot rince with plain water have been just as good? To be clear here, I'm talking about removing sugar water with traces of celulose and pectin, some assorted esters, citric, ascorbic, and malic acids, etc., not general good lab practice.

 

[StreuB1]

They say a little knowledge is a dangerous thing, and a little knowledge is just what I've got. If you're going to end with piranha solution, why the Dawn and full three minutes? Once the piranha hits it, wouldn't a good hot rince with plain water have been just as good? To be clear here, I'm talking about removing sugar water with traces of celulose and pectin, some assorted esters, citric, ascorbic, and malic acids, etc., not general good lab practice.

Oils. Dawn removes them easier than room temp piranha. If it was heated, then that is a different story. I am not swishing a glass carboy with hot piranha in it. I don't have a death wish.

 

[JackC]

The company seems to be run by Swedes. I'm still not certain the company is real, though.

 

[prfesser]

They say a little knowledge is a dangerous thing, and a little knowledge is just what I've got. If you're going to end with piranha solution, why the Dawn and full three minutes? Once the piranha hits it, wouldn't a good hot rince with plain water have been just as good? To be clear here, I'm talking about removing sugar water with traces of celulose and pectin, some assorted esters, citric, ascorbic, and malic acids, etc., not general good lab practice.

I've never used piranha---conc. H2SO4 + sodium dichromate, or KOH in alcohol, were the cleaners of choice in my formative years. But from what I've read about piranha, the vessel to be cleaned should already be reasonably clean. The reaction between piranha and organic matter is exothermic; too much organic matter *might* cause localized heating and a situation where screaming "RUN AWAY! RUN AWAY!!" might be appropriate.

So...first remove what can be removed with Dawn, rinse well to remove the residue (because detergents/soaps are organic matter), then piranha. Just in case.

Best -- Terry

 

[jqavins]

Oils. Dawn removes them easier than room temp piranha...

The reaction between piranha and organic matter is exothermic; too much organic matter *might* cause localized heating and a situation where screaming "RUN AWAY! RUN AWAY!!" might be appropriate.

Makes sense. Two good reasons. The similarity between "runaway" (phenomenon) and "RUN AWAY!" (urgent advice) is only mostly coincidental.

So...first remove what can be removed with Dawn, rinse well to remove the residue (because detergents/soaps are organic matter), then piranha. Just in case.

In my Chem 101 and 102 days, a soap or dish detergent and water wash/rinse was usually followed by an acetone rinse. If hard water was a big problem (and distilled wasn't available) then I'd use a nitric acid rinse.

 

[boatgeek]

Back to the rocketry aspects of this, one of the test burn videos had a big splash that they had achieved a higher chamber pressure than any other space company. As is obvious, they don't have stable combustion. Assuming that they're not outright lying about their chamber pressure*, would unsteady combustion give very high peak pressures even though they have crappy combustion? On a more fundamental level, does higher pressure usually correspond with good attributes like Isp? In a more chemistry direction, are the chunks of black crud flying out of the nozzle unburnt fuel?

* What can I say, I'm an optimist.

 

[dhbarr]

Back to the rocketry aspects of this, one of the test burn videos had a big splash that they had achieved a higher chamber pressure than any other space company. As is obvious, they don't have stable combustion. Assuming that they're not outright lying about their chamber pressure*, would unsteady combustion give very high peak pressures even though they have crappy combustion? On a more fundamental level, does higher pressure usually correspond with good attributes like Isp? In a more chemistry direction, are the chunks of black crud flying out of the nozzle unburnt fuel?

* What can I say, I'm an optimist.

More pressure and/or heat are easy to achieve, it's just keeping the motor and payload intact that's a bit tricky. I would guess they probably did receive at least one reading which they interpreted as high pressure.

 

[jqavins]

I have limited knowledge, so will limit myself to limited answers.

• On a more fundamental level, does higher pressure usually correspond with good attributes like Isp?
  • In general, all else being equal, and with other appropriate qualifiers, yes.
• In a more chemistry direction, are the chunks of black crud flying out of the nozzle unburnt fuel?
  • Since their fuel is liquid, no, not "unburnt fuel" as such.
  • But (and I just read this now) furfuryl alcohol can be induced by an acid catalyst to polymerize, "usually giving a black cross-linked product." That said, I rather doubt that very hot fuming nitric acid counts as an acid catalyst. Ass-kicking oxidizers at high combustion temperatures rarely^* succeed in acting as catalysts rather than reactants. But perhaps I'm exceeding my limited mandate.

* Note the choice of word. "Rarely" is not the same as "never".

 

[StreuB1]

If their acid is sh1t (likely), then they can have chaotic reactions with the FA.

Can combustion instability cause high pressure events? Absolutely. Rarely though your sample rate and the resolution of the sensor would be able to capture it as the flex of the dome in the sensor would need to hit its peak and the exact moment the DAC is takings its sample, which in order for those two events to overlap in an amateur situation, would be pure luck. Likely this is what happened as combustion instabilities can cause extreme pressure excursions of many times the design pressure but since we need to talk about the time aspect, dP/dt is what matters so the motor stays together. Keep it up though, and that instability can be like a hammer [or vibrator] and beat/rattle your motor into submission, ultimately yielding the fastener(s) into plastic deformation and then you have an loss of pressure in the chamber and its over with.

Hard starts on the other hand are events where you [usually] instantly pass from deflagration to detonation and if violent enough, ends the motor. Not always though.

 

[OverTheTop]

As is obvious, they don't have stable combustion. Assuming that they're not outright lying about their chamber pressure*, would unsteady combustion give very high peak pressures even though they have crappy combustion?

If their combustion chamber is resonating then it is likely that a pressure pulse is oscillating between a couple of locations within the chamber. Overall average pressure would be lower. Much research has been done into combustion instability and in some cases structures like Helmholtz resonators are built into the chamber to remove the resonances. Interestingly testing for combustion instability, in a marginally-stable engine, can be achieved by setting off an explosive charge in the chamber while the engine is operating, and observing the response of the engine.

On a more fundamental level, does higher pressure usually correspond with good attributes like Isp?

Roughtly higher pressure translates to higher temperature which indicates improved Isp. Remember their chamber pressure average pressure will be less than the unstable peak pressures they are experiencing. Combustion instability in HPR can give good crowd-pleasing (noisy) launches but there is an efficiency penalty to be paid.

 

[rocket_troy]

On a more fundamental level, does higher pressure usually correspond with good attributes like Isp?

Higher chamber pressure generally won't affect the c* much at all. c* is basically the impetus the propellant produces without the influence of the nozzle.

And to elaborate on that: in the air-breathing world, you would normally associate higher pressures with higher temperatures as you’re typically relating to fluid compression allowing you to extract more energy from such in the expansion process (including the jet nozzles in turbine stages). However, typically in rockets, the chemical reactions are equilibrium constrained ie. higher pressure suppresses some of the reactions from running to completion within the chamber as the chambers generally run at the limit of chemical equilibrium whereas the metallurgical constraints of the turbine stages (or whatnot) constrain most air-breathing applications to much lower temperatures ie well below the thermochemical equilibrium constraints.

Where higher chamber pressures help is with the contribution of the *nozzle* at sea level (more specifically, at higher ambient pressures). Higher chamber pressures are far less influential at altitude even for nozzles utilising high expansion ratios.
Upper stages can really utilise that aspect by shaving considerable dry mass and running at much lower chamber pressures - especially solids and blowdown fed propulsion units where a significant portion of the structure is supporting/retaining the chamber pressure.

TP

 

[boatgeek]

Thanks to everyone for the knowledgeable replies. What I'm getting is that the lead person bragging that they have a chamber pressure greater than [name-drops list of other new space companies] means that the lead person doesn't really know what they're talking about but wanted to sound impressive.

From my not-really-knowing-what-I'm-talking-about perspective, I would think that a real rocket company would be bragging about, not necessarily in this order:
Thrust
Isp
C* (maybe?)
How deeply the engine can be throttled (for propulsive landings)
Ease of maintenance/refurbishment (for reusability)

Is that a fair list? Is there something else that you'd brag about?

 

[rocket_troy]

Well, people will generally choose whatever virtue *their* system has on other systems to brag about, whether that’s Isp or c* or deep throttling capability or… with these guys, it could be how much sound and flame is produced.

Where RFNA or WFNA does shine is density. Whilst the Isp produced is comparably low, the actual delta V produced on a per *volume* basis with a NA+fuel combination is generally higher than LOX+LH2 or even non-exotic LOX+HC combinations or even non-exotic H2O2+HC combinations.

TP

 

[jqavins]

From my not-really-knowing-what-I'm-talking-about perspective, I would think that a real rocket company would should be bragging about, not necessarily in this order:
Thrust
Isp
C* (maybe?)
How deeply the engine can be throttled (for propulsive landings)
Ease of maintenance/refurbishment (for reusability)

Modified with respect to @rocket_troy's comment.

You left out the three most important things to brag about if one has them: mission capability (which is supported by those other things you listed), reliability, and price. The customers don't care about all that sciencey mumbo jumbo. Do you think a barge operator cares about its moments of inertia or the maximum compressive strength of the deck plates?

 

[dr wogz]

to quote the movie 'how to get a head in advertising":

"If it's not high in one thing, it's gotta be low in something else"

https://www.imdb.com/title/tt0097531/

 

[boatgeek]

Modified with respect to @rocket_troy's comment.

You left out the three most important things to brag about if one has them: mission capability (which is supported by those other things you listed), reliability, and price. The customers don't care about all that sciencey mumbo jumbo. Do you think a barge operator cares about its moments of inertia or the maximum compressive strength of the deck plates?

Fair, fair. I suppose it partly depends on what the rocket company is selling. If they're selling an engine (Aerojet Rocketdyne and to some extent Blue Origin), then they are selling a technical item to technical people, and they'll likely stick to technical specs and price plus a little marketing mumbo jumbo. If they're selling launches, then it's all about cost and risk to orbit for my payload and maybe secondarily what new payload options does this rocket open up (eg Falcon Heavy).

Barge operators and charterers care a lot about overall dimensions and carrying capacity (both in terms of total cargo and allowable deck load). If the owner is paying for fuel, they might care about efficiency, but this is a surprisingly hard sell. We're just having a discussion now about trying to sell an operator on using higher-strength steel to try to save a little bit of steel and therefore cost in the construction. It's a surprisingly complicated discussion, but I've derailed this thread enough.

 

[jqavins]

If they're selling an engine (Aerojet Rocketdyne and to some extent Blue Origin), then they are selling a technical item to technical people, and they'll likely stick to technical specs and price plus a little marketing mumbo jumbo.

Even there, the engine manufacturer is selling to its customer the ability to sell launches to its customer and make a profit doing it. Performance, reliability, and price are still the most important factors, though the launch provider is more likely than the end customer to want the technical details that justify the performance and reliability claims. And the end customer (or the end customer's consultant) is somewhat interested in that, just less so. "First, what performance and reliability can you deliver, and at what cost? Second, prove it."

 

[djs]

Performance, reliability, and price are still the most important factors

I feel like reliability/repeatability is the most important of these, because you can't get this without having a good understanding of the process. I mean, everyone could have a lucky day and get a super cheap motor with lots of performance. But other than "wow, check out the PSI and ISP we got on this one!" they have no idea how to duplicate it. The next one will go kafloopy and they won't know why.

 

[jqavins]

I agree, but I think we're talking about apples and a different variety of apples. What you're talking about is incompetence, early R&D, or both. What I'm talking about is a controlled, understood, and repeatable process that yields 99.9% reliability, compared to a different controlled, understood, repeatable process that yields a 95% reliable product at 50% of the price. If the payloads are neither precious nor very costly* then one might very well choose the cheap one.

"That doesn't make sense," I hear you cry. "Aren't 'precious' and 'very costly' the same? What sort of payload could be 'precious' but not be 'very costly'?"

People.

 

[Pem Tech]

my favorite went something like "the one guy running upwind is the propulsion guy who knows what nitric acid does to a person's lungs. The two guys running downwind are the mechanical guys who know what shrapnel looks like."

HA!! I had a very similar impression.

Those folks are a disaster waiting to happen.

 

[StreuB1]

Well, people will generally choose whatever virtue *their* system has on other systems to brag about, whether that’s Isp or c* or deep throttling capability or… with these guys, it could be how much sound and flame is produced.

Where RFNA or WFNA does shine is density. Whilst the Isp produced is comparably low, the actual delta V produced on a per *volume* basis with a NA+fuel combination is generally higher than LOX+LH2 or even non-exotic LOX+HC combinations or even non-exotic H2O2+HC combinations.

TP

We call that Density Impulse, and its a very good thing as long as you need it. If you need a small package, then you want to focus on density impulse. If you need pure performance, then you want Isp. Density impulse is what helps you determine packaging. This is one of the reason they are used in missiles and RATO units, not to mention simple and no ignition system required. Downside, you need a well engineered injector and chamber to get it to REALLY shine, especially when the fuel is difficult to react or the reaction time is long. In this case, they likely have sh1t acid so the reaction time is very long and the injector is poorly atomizing the propellants. Those two things combined mean you have a pulsejet more than a rocket engine due to that flame front warbling all over the inside of the chamber.

 

[StreuB1]

I feel like reliability/repeatability is the most important of these, because you can't get this without having a good understanding of the process. I mean, everyone could have a lucky day and get a super cheap motor with lots of performance. But other than "wow, check out the PSI and ISP we got on this one!" they have no idea how to duplicate it. The next one will go kafloopy and they won't know why.

Yep, its easy to have a good day. Its hard to have repeated good days as you iterate on a design. Understanding the system as a whole will give you the ability to iterate on a design and have the outcome be more or less predictable.

 

[prfesser]

The claim of chamber pressure was approx. 1400 psi. The 'expertise' demonstrated by the group with shockingly casual behavior around some rather nasty chemicals makes me wonder. Did they (A) measure the actual chamber pressure with a sensor connected directly or indirectly to the chamber? Or (as the propellants appear to be pressure-fed) (B) did they simply open the valves of the pressurizing gas, and assume that the pressure of that gas was the chamber pressure?

When I look at the exhaust, my semi-scientific spider sense tells me "That ain't operating at no 1400 psi chamber, nope nope."

Ever the skeptic,
Terry

 

[Jim Hinton]

Long experience has taught me that you can get about any gauge to read out about any number, once.

Jim

 

[Johnly]

The claim of chamber pressure was approx. 1400 psi. The 'expertise' demonstrated by the group with shockingly casual behavior around some rather nasty chemicals makes me wonder. Did they (A) measure the actual chamber pressure with a sensor connected directly or indirectly to the chamber? Or (as the propellants appear to be pressure-fed) (B) did they simply open the valves of the pressurizing gas, and assume that the pressure of that gas was the chamber pressure?

When I look at the exhaust, my semi-scientific spider sense tells me "That ain't operating at no 1400 psi chamber, nope nope."

Ever the skeptic,
Terry

Agreed and your "semi-scientific spider sense" has basis in fact and experience. It's difficult achieve that operating pressure unless you have at least 2x the pressure in the tanks due to flow losses.
The other thing of note is that they were downwind of the test, based on the NO2 cloud and while the launch control person was wearing a respirator, the person calling out the countdown wasn't. I'm sure that Terry would agree that being enveloped into a visible cloud of NO2 without PPE is a life altering experience. Fortunately, the NO2 was hot and drifted over the top of them.

When all is said, I wonder if body bags are anywhere on their checklist, or if they are expecting EMS folks to provide them? Yes, that is satire.

John

 

[Zeus-cat]

They just hired a new safety engineer; Pink Shirt Guy

 

[Grog6]

Those cotton shirts practically dissolve in hot na.