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Ban Hydrazine in Alaska

Statement of problem or issue

With the commercial space and aerospace industry booming, the use of “green” propulsion systems should be used as a method to remain Earth-sustainable.  Earth-sustainability is an important issue as we have finite resources and are currently dealing with fallout of past non-sustainable enterprises in the form of climate change.


The current standard emergency fuel for F16s (not the F35s) and the propulsion for spacecraft is hydrazine (N2H4).  It is extremely toxic, creates environmental pollution, causes many health hazards, and has high storage and handling costs (Amrousse et al, 2016).


Image 1. Anhydrous (pure, not in solution) hydrazine being loaded into the MESSENGER space probe (orbital reconnaissance mission of the planet Mercury). The technician is wearing a safety suit in overpressure with an external air supply. NASA - https://mediaarchive.ksc.nasa.gov/#/Detail/8998
Image 1. Anhydrous (pure, not in solution) hydrazine being loaded into the MESSENGER space probe (orbital reconnaissance mission of the planet Mercury). The technician is wearing a safety suit in overpressure with an external air supply. NASA - https://mediaarchive.ksc.nasa.gov/#/Detail/8998

Hydrazine is primarily found at Eielson AFB and JBER in Alaska for jet and rocket fuel use, though it is also a component of agricultural chemicals, chemical blowing agents, pharmaceutical intermediates, photography chemicals, boiler water treatment for corrosion protection, and textile dyes (Environmental Protection Agency, 2016).


Hydrazine is listed as extremely toxic and hazardous.  There are acute effects, chronic effects (noncancer), reproductive/developmental effects, and cancer risk which is covered in the 2016 data sheet from the EPA, which can be found HERE.  According to NOAA’s Cameo Chemical database, hydrazine is rated a 4 health hazard (can be lethal), 4 flammability hazard (Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.), and 3 instability hazard (Capable of detonation or explosive decomposition or explosive reaction but requires a strong initiating source or must be heated under confinement before initiation).  Response recommendations, in the case of a spill, is to 1) isolate and evacuate up to 1/2 mile is all directions, 2) prevent or deal with fire, if there is a fire special breathing apparatus and clothing is required, and 3) treat for inhalation, dermal/eye, and ingestion exposure.


In a 1983 report by the Enrivonics Division of the Air Force Engineering and Services Center (AFESC), tested hydrazine in various aqueous and soil solutions.  The aqueous solutions were deionized water, distilled water, and natural waters.  Hydrazine in these were noted as "remarkably stable".  With a PDAB assay for MMH it was found that in marine water, hydrazine had a half-life of 13 days, while 12 days was the half-life in different types of fresh water.  The TPF procedure for UDMH resulted in a higher half-life of 30 days.  Soil samples that were tested were sand, dirt from Vandenberg AFB, organic soil, and clay 10%.  The results all resulted in contaminated soil that could not have hydrazine fully extracted (Braun and Zirrolli, 1983).


With the availability of less toxic, low toxicity, and non-toxic options in 2025, Alaska should ban the use of hydrazine in the state of Alaska to prevent any accidents or mishandlings of this highly toxic compound.  Hydrazine costs the government in infrastructure, hazmat, and hazard pay, which should be taken into account.  Alternative solutions of hybrid fuel types, ionic liquids, or ABS/GOx are all more affordable with reduced government costs.

A hydrazine spill, leak, mishandling, or accident could result in water table contamination, soil contamination, toxicity to fish and wildlife, toxicity to people, and destruction of the natural environment.  The last thing Alaskans want is their fish and game environments to be contaminated by a toxic agent when there are other options available.



Alternate solutions

Hybrid Fuel Types

Hydroxyl-Terminated Polybutadiene (HTPB), Polybutadiene Acrylonitrile (PBAN), and Glycidyl Azide Polymer (GAP) are the top three hybrid fuel types that are considered "green".  These three systems all have a higher performance rate than a hydrazine system.  They are also noted for being labor intensive, having high production rates only with significant infrastructure, and using toxic materials (Whitmore et al, 2015).


Ionic liquids (IL), a naturally occurring water-soluable ammonium-salts, has been investigated as a potential propellant.  Hydroxyl ammonium nitrate (HAN) has been investigated and the most recent application was developed by the Ball Aerospace and Technology corporation (Amrousse et al, 2016).  It's less toxic than HTPB, PBAN, and GAP, but that still indicates some level of toxicity.  It uses an energy-hungry and cost-inhibitive catalyst resulting in very slow reaction kinetics for small craft with moderate or less pressure systems (Whitmore et al, 2015).  It is high density, high specific impulse, and low freezing point (Kang et al, 2023).


Acrylonitrile Butadiene Styrene (ABS) is a material that can be found in hardware stores that one might know as "black plastic pipe".  ABS has been tested as a potential propellant with promising results.  It can be put through a Fused Deposition Modeling (FDM) process which is thought to be a revolutionary manufacturing step for creating hybrid rocket fuel grains.  ABS is non-toxic.  Its measured fuel regression massflow is identical to HTPB.  It's very cost efficient.  There is a high production rate with uniform quality, consistency, and performance; which in turn reduces development and production costs (Whitmore et al, 2015).



Analysis of the pertinent data, literature, or theories

Green propellant features (Anflo & Gronland, 2002):

  • Low toxicity and noncarcinogenic

  • Non-volative

  • Low sensitivity to shock, temperature, fire

  • Not easily detonable

  • Long storage periods

  • Environmentally benign through life cycle


TYPE

PROS

CONS

Hybrid Green Fuels

 

HTPB

PBAN

GAP

  • Higher performance rate than a hydrazine (Whitmore et al, 2015)

  • Labor intensive (Whitmore et al, 2015)

  • High production rates only with significant infrastructure (Whitmore et al, 2015)

  • Using toxic materials (Whitmore et al, 2015)

HPAS (IL)

  • High density (Nosier et al, 2021)

  • Nontoxic (Nosier et al, 2021)

  • ~20% less performance than hydrazine (Nosier et al, 2021)

  • Requires catalyst bed to operate (Walker, 2015)

Liquid NOx (IL)

  • Highest Performance of Ionic Liquid (Nossier et al, 2021)

  • Relatively Non-Toxic (Nossier et al, 2021)

  • Requires catalyst bed to operate (Walker, 2015)

HAN (IL)

  • High Soluble and Negligible vapor-pressure (Nossier et al, 2021)

  • Low Toxicity (Nosier et al, 2021)

  • High mixture stability at various temperatures (Nosier et al, 2021)

  • Met all propulsion requirements upon testing, includes: threshold, primary divert modes, flight verification thresholds, and ADCS control thresholds (McLean, 2020)

  • ~2% increased performance compared to hydrazine (McLean, 2020)

  • Difficult to rapid manufacture  (Nosier et al, 2021)

  • Requires catalyst bed to operate (Walker, 2015)

HPAS (IL)

  • Lowest Performance of Ionic Liquid (Nosier et al, 2021)

  • Low Toxicity (Nosier et al, 2021)

  • Requires catalyst bed to operate (Walker, 2015)

ADN (IL)

  • Multiple methods of ignition (Nosier et al, 2021)

  • Lower combustion temps (Nosier et al, 2021)

  • Nontoxic (Kang et al, 2021)

  • Recommended for electrospray technique (Kang et al, 2021)

  • No ignitable fumes produced (Anflo & Gronland, 2002)

  • Requires catalyst bed to operate (Walker, 2015)

Hydrocarbon NOx (IL)

  • High stability (Nosier et al, 2021)

  • Moderate combustion temps (Nosier et al, 2021)

  • Better ignitability (Nosier et al, 2021)

  • Nontoxic, noncarcinogenic (Nosier et al, 2021)

  • Low freezing point (Nosier et al, 2021)

  • High specific impulse (Nosier et al, 2021)

  • Self-pressurization (Nosier et al, 2021)

  • Requires complex engines and cooling system (Nosier et al, 2021)

  • Requires catalyst bed to operate (Walker, 2015)

98% HTP (IL)

  • Nontoxic (Florczuk & Rarata, 2017)

  • Low volatility (Florczuk & Rarata, 2017)

  • Stable (Florczuk & Rarata, 2017)

  • Can be coupled with other propellants for higher performance (Florczuk & Rarata, 2017)

  • Fast ignition (Florczuk & Rarata, 2017)

  • Requires catalyst bed to operate (Walker, 2015)

ABS

  • Nontoxic (Walker, 2015)

  • Very stable, can be handled in normal “shirt sleeve” commercial environment (Walker, 2015)

  • Reduced production, operational, transportation costs (Walker, 2015)

  • Able to be 3D printed (Walker, 2015), ABS Plus-P430 recommended (Whitmore, 2022)

  • Reduced costs due to reduced subsystem complexity and overall system interface complexity (Walker, 2015)

  • During testing ABS was equivalent to HTPB in specific impulse, characteristic velocity, fuel regression massflow rate (Walker, 2015)

  • Inexpensive thermoplastic material (Walker, 2015)

  • NASA classifies ABS as “low out gassing” material under vacuum conditions (Whitmore, 2022)

  • 100% combustion efficiency (Whitmore, 2022)

  • Low power ignition – started, stopped, restarted (Whitmore & Bulcher, 2017)

  • An ABS/Gox system can be used as a drop-in replacement for a hydrazine system (Whitmore, 2018)

  • New enough as a fuel source to not have a plume contamination database

  • Some plume contaminates upon recent testing resulting in 10-35%.  In comparison, hydrazine has 40-50% (Whitmore, 2022)


Recommendation for action and why

After comparing green alternative fuel sources, my conclusion is that ABS/GOx is the best green fuel option.  For this method, ABS is paired with injected gaseous oxygen (GOx) to create fuel.  It can also be directly used to replace hydrazine with a “drop-in” unit.


Image 1. Display of ABS fuel grains in a) a range of forms and b) identical 3D printed grains. (Whitmore, 2022)
Image 1. Display of ABS fuel grains in a) a range of forms and b) identical 3D printed grains. (Whitmore, 2022)

The general rule of thumb for rocket fuel is: for every pound of payload, you need 50 pounds of propellant. Let's run a general cost analysis for a small rocket requiring 100 pounds of fuel. The cost of hydrazine is roughly $85 per pound. The weight of ABS required to be equivalent to a pound of hydrazine is between 20-35% less in weight, we can use 20% for a high-end cost. ABS filament ranges from $50-125 per 5 pound spool depending on retailer.


Cost chart below.

Hydrazine




$85/pound

100 pounds needed

$8500 for 100 pounds

Additional costs will include: cryogenic storage, hazmat training, personnel team, cryogenic transportation from factory, high manufacturing cost, etc.

ABS/gOX




$85/pound

80 pounds needed

$6800 for 100 pounds

Additional costs will include: 3D printer, gaseous oxygen, shelves for storage, limited personnel.


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