In the Armstrong Facility, the DC-101 Tenacity made its grand debut in front of the press and media. Positioned on a towering 55-foot vertical test stack, this spaceplane is set to become the first privately-owned spacecraft to operate in low-Earth orbit. Serving as a successor to the retired Space Shuttle, the Tenacity is a scaled-down version with a more practical size, but it still carries the weight of high expectations.
The Dream Chaser Tenacity is the inaugural product produced by Sierra Space since separating from the larger Sierra Nevada Corporation. As an independent entity, Sierra Space focuses on various technological advancements, ranging from solar arrays to rocket propulsion systems. Their expertise extends to the development of reusable spaceplanes, and the Tenacity stands as their first commercial offering.
While the Tenacity is undeniably groundbreaking as a private orbital spaceplane, its design draws inspiration from NASA’s past vehicles and concepts. The X-20 Dyna-Soar program, although ultimately canceled, influenced the construction of the Tenacity’s lifting body. Additionally, advancements in lifting body airframes by Northrop and Martin Marieta played a crucial role in refining the flight characteristics of the Tenacity. NASA’s own conceptualization of a small spaceplane, known as the HL-20, shared striking similarities in dimensions with the Dream Chaser. Although the HL-20 never took flight, it was intended to serve the International Space Station alongside the Space Shuttle.
The design of the HL-20 became the primary inspiration for a group of engineers at SpaceDev, a startup aerospace firm based in Southern California. In 2004, SpaceDev unveiled plans to develop a custom spaceplane based on the HL-20 architecture. Subsequently, they entered into an agreement with the United Launch Alliance to construct the carrier rocket platform for this ambitious design. The culmination of their efforts resulted in the Vulcan Centaur rocket, featuring the latest advancements in the Centaur upper rocket stage, which traces its roots back to the Apollo era. Although SpaceDev is no longer in existence and has been absorbed into Sierra Space, their seventeen years of dedicated development led to the prestigious Northern Ohio test facility, where the Tenacity now stands.
A group of notable individuals from Sierra Space, accompanied by representatives from NASA and the media, gathered at the Space Environmental Complex. Among those present were Tom Vice, the CEO of Sierra Space and former President of Northrop Grumman’s Aerospace Systems division, Dr. James A. Kenyon, Director of NASA’s Glenn Research Center, and Dr. Thomas Marshburn, Sierra Space’s Chief Medical Officer and a former NASA astronaut. Through negotiations led by Marshburn, Dream Chaser secured contracts for at least seven resupply missions to the International Space Station once full-scale production begins.
During the press conference, Dream Chaser made its debut alongside the Shooting Star cargo module. With a length of 15 feet (4.6 m) and a capacity to carry 11,000 lbs (5,000 kg) of pressurized and un-pressurized cargo, the additional storage space on board will serve as a crucial lifeline for the ISS crew, ensuring they receive the necessary supplies from Earth.
As NASA, Sierra Space, and the media approached the Space Environments Complex, they were greeted by the sight of the nearly completed Tenacity, accompanied by Shooting Star. The spacecraft’s exterior featured heat-resistant panels inspired by the carbon-carbon tiles used in the Space Shuttle program, designed to withstand the intense heat and friction of re-entry into the atmosphere. Prior to launch, the remaining sections of the spacecraft will be covered with heat absorption tiles.
Before its inaugural rendezvous with the ISS later this year, Tenacity will undergo rigorous testing at the Mechanical Vibration Facility to assess its structural strength under the immense forces experienced during launch and re-entry.
Dream Chaser’s first flight will be unmanned, hence the absence of cockpit glass on DC-101. When its wings were folded in the stowed position on the test stand, it became evident that the wing design drew inspiration from US Navy jets stationed on aircraft carriers.
Dream Chaser embodies the fundamental principles of the retired Space Shuttle orbiters, but in a more compact form that allows for efficient large-scale production and maintenance. The potential of a fleet of space planes capable of consistently delivering equipment and supplies to the ISS surpasses what the Shuttle could achieve in terms of frequency and reliability.
Looking ahead, Sierra Space aims to complete the first Dream Chaser rendezvous with the ISS, accompanied by Shooting Star, by the first half of 2024. Subsequently, they will begin constructing the DC-200 series spaceplane, designed to transport human astronauts.
Sierra Space will keep performing essential vibration and acoustic tests on DC101, in collaboration with NASA, prior to addressing the remaining few administrative tasks for the upcoming launch, expected to take place in the late spring or early summer of 2024. Given such a timeline, it is nearly impossible not to feel a sense of anticipation.