Northrop Grumman Corp. [NOC] completed manufacturing and integrating a spacecraft engine that runs on "green," non-toxic propellants — liquid oxygen and liquid methane — for possible use on NASA human exploration missions to the moon, Mars and beyond.

The company’s TR408 second-generation, oxygen-methane 100 pound-force reaction control engine (RCE) was designed for the Propulsion and Cryogenics Advanced Development Project within NASA’s Exploration Technology Development Program.

The engine features robust operation over widely variable propellant conditions. Propulsion systems using engines like the TR408 may have the potential to use green propellants produced from lunar or Martian soil, according to Northrop.

It would be possible to grow crops on Mars, perhaps under a dome with conditioned air, because the Phoenix lander confirmed there is water in abundance on the red planet, in the form of ice.

Melting the ice into water means it can irrigate crops.