By Kristal

Let’s say we have a choice between 4

different types of liquid propellants to

choose from for a space mission.

Example:

Reactants (Propellants) Chemical Reaction

Hydrogen and Oxygen H2(g) + ½ O2(g) H2O(g)

Methylhydrazine and Nitrogen

Tetroxide

H2NN(CH3)2(l) + 2 N2O4(l)

3 N2(g) + 2 CO2(g) + 4 H2O(g)

n-Dodecane and Oxygen C12H26(l) + 37/2 O2(g)

12 CO2(g) + 13 H2O(g)

Ethanol and Oxygen C2H5OH(l) + 3 O2(g)

2 CO2(g) + 3 H2O(g)

1. The environmental impact of using reactants

and releasing products into the environment.

2. The safety and toxicity of the reactants used.

3. An evaluation of the use of an ignition system

or catalyst.

4. The total mass of spacecraft remember the

goal is to minimize the total mass.

Environmental Impact: Using Hydrogen has no

environmental impact.

Safety: Hydrogen is a colorless, odorless, tasteless and

extremely explosive. To prevent Hydrogen leaks

Hydrogen sensors should be installed in order to rapidly

detect suck leaks. An odorant can also be added to the

liquid to detect leaks by smell. Hydrogen flames are

hard to see with the naked eye, so flame detectors

should be installed as well.

Environmental Impact: Using Methylhydrazine and Nitrogen

Tetroxide has a major impact on groundwater. When the

chemical is spread in the air it pollutes groundwater

endangering wildlife.

Safety: Methylhydrazine is highly toxic. It can cause

permanent and non-permanent health issues. It is can cause

cancer for humans. To add to that its vapor is very flammable

and explosive. To prevent any hazards all containers and

handling equipment should be electrically grounded and in an

inert atmosphere. Avoid strong oxidizers, avoid contact with

metal oxides and avoid contact with organic material.

Environmental Impact: Using n-Dodecane is toxic to fish,

algae and aquatic invertebrates. It endangers aquatic

life

Safety: n-Dodecane can be very harmful to humans if

exposed to high concentrations over PAC-3. To prevent

hazards an Air-Purifying Respirator should be installed.

Prevent leaking and dress accordingly: protective

gloves, safety goggles, protective suit, safety shoes.

Environmental Impact: Using Ethanol emits air

pollution into the atmosphere that increases the

risk of air pollution deaths by 9%.

Safety: Dress accordingly: protective gloves, safety

goggles, protective suit, safety shoes. Because it is

flammable keep away from oxidizers.

I choose the 1st propellant, Hydrogen and

Oxygen, because:

It is the safest propellant

It is the cleanest propellant

NASA is currently using this type of

propellant

It is an efficient propellant

It isn’t too heavy

To conclude my presentation I believe that

Hydrogen and Oxygen, H2(g) + ½ O2(g) H2O(g), is

the best propellant because it has a better

overall outcome then the rest. It is clean, easy

to use, light, safe, has a low toxicity and creates

a good thrust.