There's a lot riding on the development of Sierra Nevada's Dream Chaser space plane, with agreements in place to deliver cargo to the International Space Station for NASA, while other parties have expressed an interest in its services, too. The company has now offered the public the first fiery look at the engine that will propel it through space, with missions for NASA slated to kick off the year after next.

Since its first attempt at gliding test flight left it upside down on the airstrip way back in 2013, the road has been a relatively smooth one for Sierra Nevada's reusable orbital vehicle. That incident led to a total refurbishment and it then completed its first captive carry test flight in August 2017 where a Chinook helicopter hoisted it into the air, and then its first successful gliding flight and landing test just a few months later.

The Dream Chaser is designed to be launcher agnostic, meaning it could be lifted into space with the help of a number of different rockets. But the propulsion technology Sierra Nevada publicly demonstrated for the first time last week is an upper stage engine, meaning it will ignite at high altitudes and propel vehicles like the Dream Chaser as they travel through the upper parts of the atmosphere.

Sierra Nevada says it expects the engine, dubbed the Vortex, to save tens of millions of dollars per launch because of its efficient design, along with relatively low manufacturing and maintenance costs.

The first public demonstrations are another milestone for the company in its efforts to get the Dream Chaser into action, with US Senator Tammy Baldwin on hand to witness the action at its Wisconsin facility.

"This is an important day for our Made in Wisconsin economy and for US space launch technology, and I'm proud to champion investments that will spur innovation, boost manufacturing and promote 250 good paying, clean energy jobs right here in Wisconsin," said Senator Baldwin.

NASA awarded the Sierra Nevada a private contract to begin delivering cargo to the International Space Station back in 2016. Under the agreement, it will carry out at least six resupply missions carrying essentials like food and water, and can also retrieve around 7,400 lb (3,400 kg) of waste each time it departs.

Last December, NASA completed a design and performance review of the vehicle and gave it the all clear for production. Sierra Nevada says it will begin servicing the International Space Station for NASA in spring of 2021.

View gallery - 3 images