Hydrazine (N2H4)

 H       H
  \     /   
   N - N
  /     \
 H       H 
Primarily used as a fuel, especially in satellites for station-keeping. Hydrazine itself is toxic, flammable, caustic, and has strong reducing properties and smells vaguely of ammonia. It is soluble in water and most alcohols. Fuel grade Hydrazine has a density of 1.01g/cc, freezes at 2.00 C and boils at 113.00 C.

The creation of hydrazine is done through the Raschig process. This involves the oxidation of ammonia to chloramine. Chloramine is then reacted with ammonia again. In 1959, the cost of anhydrous hydrazine in industrial quantities was $7.00/kg. It was projected that the price per unit would drop to $1.00/kg from large scale commercial production, however due to environmental regulations, NASA was paying $17.00/kg.

NASA Lewis Research Center and Primex Aerospace Company have developed an environmentally friendly monopropellant that is intended to replace the use of hydrazine thrusters on most spacecraft. This compound is hydroxylammonium nitrate (HAN). Tests on these new thrusters show that it has a specific impulse of 195 sec and a density-specific impulse of 275 g-sec/cm3. This is about 25% greater than current state of the art hydrazine thrusters.