Lessons Learned: Rockets in the 1980s and 1990s and now

[Steven Pietrobon]

The system proposed for the Loral/Microcossom Aquarius LV sounded interesting, GH2 to pressurize LOX. They did some tests as well.

Man, I would have thought that is just asking for trouble!

1.  It is not a big deal, you just have to be up wind.  Actually, HTP is more dangerous

Result of pouring thimble of 85% HTP on your head: Hair catches on fire and you are badly burned. Fire put out with water.

Result of pouring thimble of N2O4 or Hydrazine/MMH/UDMH on your head: Death (not 100% sure, but I think that result would be likely as the fumes are extremely toxic).

2. UDMH is not used much any more.  Either hydrazine or MMH.

That is in the US and Europe. The Russian Proton and Chinese Long March 2/3/4 series still use large quantities of UDMH.

[jongoff]

Result of pouring thimble of 85% HTP on your head: Hair catches on fire and you are badly burned. Fire put out with water.

I actually had some friends have 85+% HTP "rain" on them once. We were out at the Friends of Amateur Rocketry site to fly Xombie to a high altitude, and after we wrapped up, Paul Breed went to fly his Blue Ball lander to a high altitude (>1000ft in each case). Paul's vehicle lost control on the way up due to a roll instability, which triggered the hard abort code, venting the HTP tank at high altitude, under pressure, and dropping the vehicle from several hundred feet up.

Most of us (including my wife and my three boys at the time, and some Masten coworkers/interns/friends) were watching from inside a bunker. Once we saw that the vehicle had hit the ground and was vented, everyone assumed the coast was clear. So they stepped out to go see what had happened. That's when the rain of HTP droplets from the vented high-pressure tank started raining on everyone. Luckily none of it ended in anyone's eyes, but it also didn't catch anyone on fire. We doused the hit spots with water quickly, and all that really happened was some stinging/bleaching.

Some guy's pickup truck bed did catch fire though when the peroxide landed on the oily residue that usually builds up in a pickup truck's bed. But that was also put out quickly.

Peroxide like most powerful oxidizers demands respect, but I'm less afraid of it than say Nitrous.

~Jon

[john smith 19]

The system proposed for the Loral/Microcossom Aquarius LV sounded interesting, GH2 to pressurize LOX. They did some tests as well.

Man, I would have thought that is just asking for trouble!

1.  It is not a big deal, you just have to be up wind.  Actually, HTP is more dangerous

The presentation I saw said it could in fact be detonated by sunlight. 

That said Aquarius was designed for ISS resupply of low value items and they targeted a 20-33% failure probability. Stuff like ready meals and replacement uniforms. It was a bold strategy and I wish NASA had kept at it. 

Result of pouring thimble of 85% HTP on your head: Hair catches on fire and you are badly burned. Fire put out with water.

Result of pouring thimble of N2O4 or Hydrazine/MMH/UDMH on your head: Death (not 100% sure, but I think that result would be likely as the fumes are extremely toxic).

But Isp beats all other considerations if you're the military, or someone else is paying to have the problems of toxicity dealt with.

I don't think I've heard of any amateur group ever using NTO/Hydrazine.  The only time it's come close was a Phillips project in the 60's for a Hydrazine fuel cell moped.

2. UDMH is not used much any more.  Either hydrazine or MMH.

That is in the US and Europe. The Russian Proton and Chinese Long March 2/3/4 series still use large quantities of UDMH.

The French got to orbit with it ahead of the UK with their Diamant design. I don't see anyone planning to revive that, or the Titan. It's a case of what was acceptable in the 60's is simply not today.

Nitric Acid is much less volatile than NTO.
Amines (R-NH2) have toxicity and volatility much less than Hydrazines (R-NH2-NH2-R).

I tend to class anything that looks like ammonia loosely as an amine. You're right it's a different group.

Though they have relatively low energy, poorer long term storable behavior, high freezing point.

The last two should not matter for an LV, the first might be a concern. Ammonia was certainly used for the X15. The trouble is keeping it water free seems to be important and a real PITA.

Nitric Acid / Amine or Nitric Acid / Turpinetine combination have been successfully used (before NTO and Hydrazine) in French "Diamond" launcher to orbit.

Interorbital Systems (remains of OTRAG) is still using Nitric Acid / Turpinetine today, though with a very small rocket.

The one that's never seemed to have been tried is Propyne, whose strained triple bond is expected to be more energetic than most hydrocarbons. It's also meant to be available in large quantities but I don't know if they resolved wheather it's carcinogenic or not. 

[Katana]

Trouble with ammonia in X-15 is the difficulty to ignition and have stable combustion, which eventually require unusual multi stage combustor design.

Propane (LPG) have isp very near to kerosene but inferior density. Vector is trying propylene, with slightly better energy characteristics and flame speed.

Propyne as well as acetylene with carbon triple bond could decompose and detonation in liquid state.

Tweak too much on liquid propellant chemistry rather than engine design has little value, Except satellite monoprellant with ADN. It's solids that chemistry real matters. From asphalt/KP to APCP (polysulfate, HTPB) to energic materials and energic polymers.

This maybe why the book <<Ignition >> are written about liquids but does Not disclose anything on solids.

[Katana]

But small engines below certain scale are impossible to regenertive cooling , since the ratio of surface area / volume rise too high at small scale.

The 10 kN Ausroc I kerolox engine used regenerative cooling, so that places an upper limit. That engine was pretty small.

You can use regenerative cooling on engines even smaller than that. The 40 lb (~175 N) RCS thrusters on the Lynx use regenerative cooling.

It may include large fractions of film cooling, similliar to Armadillo engines with pure film cooling, low performance.

[Jim]

Result of pouring thimble of N2O4 or Hydrazine/MMH/UDMH on your head: Death (not 100% sure, but I think that result would be likely as the fumes are extremely toxic).

Not all.   Just don't breath in the fumes

[Katana]

No commercial vehicle win by seeking trouble.

[mmeijeri]

No oxidizer easier to handle than white nitric acid (without NTO added), except solids (AP) and Air.

D'oh! How could I have forgotten about hydrogen peroxide? How about stabilised hydrogen peroxide?

[Gliderflyer]

It may include large fractions of film cooling, similliar to Armadillo engines with pure film cooling, low performance.

Without going into too much detail, it is purely regenerative doesn't use film cooling. Overall the performance is similar to traditional storable hypergolic systems.

[john smith 19]

I guess one take away is that no one really starts an LV company in a vacuum.

Different people bring different skill sets and have different goals for their final vehicle.

If you know solids you'll probably use a solid stage (or 2, or 3) somewhere in the design. If your goal is lowest cost that will suggest certain approaches. If you are targeting micro launch that opens up some avenues and closes down others.

Again the question of what any new LV company can bring that is not already being done has to be asked. Which begs the question which parts of the design space have not been explored and can be explored on a reasonable budget?

NASA has done work on fuels giving hybrids Isp closer to solids. That suggests a large rocket could be made without a turbopump and tapping some heat from the head end of the fuel chamber to pressurize LOX as the oxidizer. That leaves the major electronics in the GNC and the major mechanical complexity in the TVC system.  It would also eliminate the safety issues of mfg & transporting large masses of solid propellant.

The problem remains that it is very difficult to come up with something that can deliver what a TSTO ELV delivers in terms of payload fraction (and hence price), but with better operations and/or price at anywhere close to its development budget. HTOL lets you do 3x (or better inside an inducing duct) the GTOW for the same thrust but now you're into aircraft design. That said air breathing seems to be the only relatively accessible technology to get Isps above the mid 100s of secs for any length of time.
[EDIT that buys a bigger structural mass fraction that lets you build an airframe more akin to the mass fractions aircraft use, rather than VTO ELV's, which are good for the same reason that soda cans have good mass fractions (about 1/30) ]

[Katana]

No oxidizer easier to handle than white nitric acid (without NTO added), except solids (AP) and Air.

D'oh! How could I have forgotten about hydrogen peroxide? How about stabilised hydrogen peroxide?

Goverment agencies have tried to switch to HTP instead of NTO, but returned to NTO again ,including X-37B.

Turbopump of Soyuz require only 70% concentration of hydrogen peroxide and exists long, but 70% is not enough for main oxidizer.

[john smith 19]

Goverment agencies have tried to switch to HTP instead of NTO, but returned to NTO again ,including X-37B.

It's the infrastructure issue. The proposed X27b engine was an old one from the 1950's designed as an aircraft booster "super performance" engine. AFAIK it ran fine in tests but spare parts would have been a problem, so back to NTO/Hydrazine.  IIRC did a pressure fed upper stage with HTP and composite tanks which demonstrated composite tanks could hold it but it never went to full stage mfg. 

Turbopump of Soyuz require only 70% concentration of hydrogen peroxide and exists long, but 70% is not enough for main oxidizer.

Whereas Russia has kept up it's HTP infrastructure.
Historically anything up to about 90% has been quite viable but I'd guess the Russians feel the exchange rate on weight savings Vs extra payload to orbit is too high to sacrifice the operating history. IIRC for most TSTO's you'd need to save about 13Kg on the first stage to deliver 1Kg extra to orbit. 90% is 23% more dense than 70% (roughly). I don't know how many Kg of Peroxide they carry but I suspect the payload improvement is too much pain for too little gain. 

[Danderman]

We're getting into the subject of everyone's favorite propellant/oxidizer combination, whereas the subject is about specific cases of private companies building rockets.

Even the best propellant combination cannot save a company that is poorly managed.

On a different subject, Kistler spent a huge amount of money, and did not seem to leave a trace. Not many ex-Kistler employees out there.

[edkyle99]

We're getting into the subject of everyone's favorite propellant/oxidizer combination, whereas the subject is about specific cases of private companies building rockets.

Even the best propellant combination cannot save a company that is poorly managed.

On a different subject, Kistler spent a huge amount of money, and did not seem to leave a trace. Not many ex-Kistler employees out there.

What was Kistler's payload?  Did it have a kick-off customer?  It had, but lost one with COTS.

Orbital and SpaceX both had a deep-pocket kick-off customer, and they both generally met that customer's goals. 

That's the key, I think.  A kick-off customer kept happy by development progress on the new launch vehicle.

 - Ed Kyle

[RanulfC]

Propane (LPG) have isp very near to kerosene but inferior density. Vector is trying propylene, with slightly better energy characteristics and flame speed.

Sub-cooled, (LOX temperature*) propane is a bit denser than normal temp kerosene and retains the higher isp.
See: http://web.archive.org/web/20090203154304/http://dunnspace.com/alternate_ssto_propellants.htm

This maybe why the book <<Ignition >> are written about liquids but does Not disclose anything on solids.

"Ignition" deals quite a bit with various types and uses of different liquid propellants that the author worked with during early rocket research. It has more than a few bias built in as a result. Like most early texts, (despite being 'updated' it still lacks a great deal of actual new information on propellants other than the ones suggested as the 'better' ones) it lacks a lot of newer information and work but is still considered and used as the 'standard' research book on propellants.

H2O2 stored in properly vented containers and handled with appropriate care and caution which is no more difficult than most mildly caustic chemicals and actually far less than for something like Hydrazine/MMH/UDMH as shown by British experience with operations and use. American "experts" have had a dislike for peroxide since before WWII, going as far as to sabotage efforts when ordered by the Army to undertake experiments to evaluate possible German use. (Built a non-vented peroxide tank in the middle of an empty field and had it filled and left over the weekend. When it exploded due to pressure build up they then wrote a report on the unsuitability of peroxide due to it being impossible to store)

It's no worse in any respect than any other propellant being used in regular operations today and in many ways a FAR better and safer oxidizer to use as long as you don't need peak ISP.

*Very not-well-known fact is that peroxide stored at 40F does not in fact decompose at all. FMC stored a batch of 98% H202 in an air conditioned storage unit for over 17 years and the batch showed NO decomposition when tested and no loss of volume even though it was vented.

Randy

[HMXHMX]

We're getting into the subject of everyone's favorite propellant/oxidizer combination, whereas the subject is about specific cases of private companies building rockets.

Even the best propellant combination cannot save a company that is poorly managed.

On a different subject, Kistler spent a huge amount of money, and did not seem to leave a trace. Not many ex-Kistler employees out there.

One of them, Rob Meyerson, is President of Blue Origin.

[RanulfC]

Result of pouring thimble of N2O4 or Hydrazine/MMH/UDMH on your head: Death (not 100% sure, but I think that result would be likely as the fumes are extremely toxic).

Not all.   Just don't breath in the fumes

Ever, again, because till it's totally cleaned that's the most direct route of ingestion. However you'd be very wrong there Jim, it can be absorbed through the skin or across the eyes as either liquid or fumes. And that thimble full will also expose and probably be fatal to anyone within a 5 to 10 foot radius as it spreads.

See: http://www.toxipedia.org/display/toxipedia/Hydrazine

You not only require sealed breathing units to handle these propellants but full environmentally sealed suits and inner garments. Fumes are the most direct exposure route but are far from the only one.

Randy

[Danderman]

Which begs the question as to where the rest of the Kistler people went, apart from the top brass.  They spent > $500 million, but it is not clear to me that they didn't blow it on sub contractors rather than staffing up themselves.

Which gets us into the management side of the Lessons Learned.

[Danderman]

Result of pouring thimble of N2O4 or Hydrazine/MMH/UDMH on your head: Death (not 100% sure, but I think that result would be likely as the fumes are extremely toxic).

Not all.   Just don't breath in the fumes

Ever, again, because till it's totally cleaned that's the most direct route of ingestion. However you'd be very wrong there Jim, it can be absorbed through the skin or across the eyes as either liquid or fumes. And that thimble full will also expose and probably be fatal to anyone within a 5 to 10 foot radius as it spreads.

See: http://www.toxipedia.org/display/toxipedia/Hydrazine

You not only require sealed breathing units to handle these propellants but full environmentally sealed suits and inner garments. Fumes are the most direct exposure route but are far from the only one.

Randy

Despite the theoretical wonder of H2O2, actual experience in commercial spaceflight tells us that companies mostly choose not to use it on operational vehicles, and companies that did choose it tend to disappear. That is the Lesson Learned from their experience.

[RanulfC]

Despite the theoretical wonder of H2O2, actual experience in commercial spaceflight tells us that companies mostly choose not to use it on operational vehicles, and companies that did choose it tend to disappear. That is the Lesson Learned from their experience.

But that seems to have had very little to do with the use of H2O2 itself but other factors, therefore the "Lessons Learned" may be very different from the oxidizer choice. Commercial companies, by default, will tend towards choosing components, systems, and even propellants from readily available sources that have existing infrastructures and economic prices. It is how those choices among others are organized rather than the specific choices that decide if a company succeeds or fails. Failure is often laid at the 'feet' of a specific factor or choice which arguably has very little to do with the ultimate cause of the failure. And continuing to suggest that a choice or factor that was in fact NOT responsible for the failure simply continues to propagate a 'paper-virus' of misinformation instead of actually leading to specific "lessons" that should be learned to avoid such failures.

If you are actually trying to point out "Lessons Learned" from past failures it is much more effective to find the specific and direct "lessons" rather than trying to pin the 'blame' on factors and choices that had little or no effect on the actual reasons for failure.

"Correlation does not imply Causation" after all.

Randy