Spark plug and associated propellant ignition system

A spark plug comprising:

• an insulating body defining a longitudinal axis and comprising a base portion and an obstruction portion;
• a first electrode comprising a proximal portion, a distal portion and a sheathed portion between said proximal portion and said distal portion, said sheathed portion of said first electrode extending through said base portion of said insulating body;
• and
• a second electrode comprising a proximal portion, a distal portion and a sheathed portion between said proximal portion and said distal portion, said sheathed portion of said second electrode extending through said base portion and said obstruction portion of said insulating body, said first electrode and said second electrode being spaced apart to define a gap therebetween,
• wherein said obstruction portion axially extends beyond said distal portion of said first electrode, wherein said obstruction portion is positioned in flow alignment with said gap with respect to a flow path of a rocket propellant to sustain a flame proximate said gap, and wherein said obstruction portion is positioned downstream of said gap with respect to said flow path of said rocket propellant.