NASA has set an April 30 deadline for submitting technology demonstration proposals for green propellant alternatives to hydrazine, the highly toxic fuel extensively used on all manner of spacecraft, including Earth-orbiting satellites and human spaceflight vehicles.

NASA said it is looking for an alternative that decreases environmental hazards and pollution, poses fewer operational hazards and shortens launch processing times.

NASA anticipates making one or more awards under the solicitation, with no single award exceeding $50 million. The solicitation, issued by NASA’s Space Technology Program, was posted Feb. 8 on the Federal Business Opportunities website.

NASA spokeswoman Kim Newton said agency officials expect to make their selections in July and award contracts in August.