Propulsion technologies are the key to exploring the outer solar system, and many organizations have been working on novel ones. One with a long track record is the Ad Astra Rocket Company, which has been developing its Variable Specific Impulse Magnetoplasma Rocket (VASIMR) system for decades. However, this type of electric propulsion system requires a lot of energy, so the company has opted for a unique tie-up for a power plant that could solve that problem—a nuclear reactor.