An In-Depth Look At The Next Modern Spaceplane
Over a decade ago the Space Shuttle was retired after over 100 different missions. Despite a few flaws, the spacecraft was considered a marvel of technology and helped create the International Space Station and other valuable space infrastructure. Unfortunately, multiple events proved that the Shuttle was not quite safe enough to continue flying humans.
Today in 2023, we could be only months away from the first launch of a new generation of Spaceplanes. Dream Chaser while much smaller, is trying to provide a rapidly reusable platform with other benefits thanks to its unique design. For around 20 years now this vehicle has been in development going through different tests, manufacturing processes, and designs, just to name a few.
Between its folding wings, multiple variants, and new heat shield design, Dream Chaser has a lot going for it and could become a primary way to access space. Here I will go more in-depth into the exact design of Dream Chaser, what the first launch will look like, what to expect in the coming months, and more.
Dream Chaser Design
Currently, there are three different Dream Chaser variants however the cargo version is about to launch and is currently the main focus of Sierra Space. The cargo version of the SNC Dream Chaser is called the Dream Chaser Cargo System (DCCS) and after development completes planned to happen late this year, will fly resupply flights to the ISS under NASA’s Commercial Resupply Services-2 program. Featuring an expendable cargo module mounting solar panels, the spacecraft will be capable of returning 1,750 kg (3,860 lb) to Earth while undergoing maximum re-entry forces of 1.5G.
Focusing on the design, this cargo variant will have folding wings. This is because in order to meet CRS-2 guidelines, the cargo Dream Chaser needed to have folding wings and fit within a 5 m diameter payload fairing, in contrast to the Crewed Dream Chaser, which is intended to launch without a fairing. The ability to fit into a payload fairing allows the cargo version to launch on any sufficiently capable vehicle, such as Ariane 5 as well as Vulcan, and a few others. While the Dream Chaser spacecraft is reusable, parts of it will be expended on a normal mission. Specifically, an expendable cargo module will launch attached to the back of the spacecraft, expanding the cargo uplift capacity and supporting the disposal of up to 3,250 kg (7,170 lb) of trash. Total uplift is planned for 5,000 kg (11,000 lb) pressurized and 500 kg (1,100 lb) unpressurized. The expendable cargo module is called “Shooting Star”.
One of the most important parts of a reusable spacecraft is its heat shield. This not only is important for protection of the spacecraft and cargo during reentry but also for turnaround time and the number of repairs or replacements needed after a mission. For these reasons among others Sierra Space has put a lot of time into developing an extremely high quality heat shield for the spaceplane. In regard to this, last month the company tweeted saying, “Sierra Space has been selected by #NASA to help advance technologies related to NASA’s Moon to Mars objectives, with the development of a low-cost high temperature reusable thermal protection system (TPS).” The Dream Chaser thermal protection system is made up of silica-based tiles (for most of the belly and upper portion of the heat shield), and a new composite material called Toughened Unipiece Fibrous Reusable Oxidation Resistant Ceramic (TUFROC) to cover the nose and leading edges. The black and white tiles across the body are positioned in specific ways to reflect heat on parts of the spaceplane.
At its core, the Dream Chaser spacecraft is meant to shift the paradigm of LEO crew and cargo transportation. The appeal of the spaceplane starts with the reusable lifting body design expected to offer frequent, on-demand, flight opportunities with customizable mission parameters for a variety of utilization goals. SNC’s Dream Chaser offers variable internal cabin layouts, mission durations, altitudes, and inclinations within the capabilities of the lifting body.
A Dream Chaser spacecraft full of completed experiments, or a combination of experiments and crew, are exposed to less than 2G on entry, and the vehicle can land on any commercial runway longer than 10,000 ft (2438 m). The company highlights that shorter runways can be assessed on a case-by-case basis. Thanks to the runway landing the spaceplane features immediate access to completed experiments and crew following touchdown.
On August 14, 2019, it was announced that all six Dream Chaser CRS-2 flights would be carried into orbit by ULA’s Vulcan launch vehicle, with the first Dream Chaser flight being the second Vulcan flight in late 2021. However, on February 9, 2022, Ken Shields, Sierra Space’s Director of Commercial Market Development, announced that the first flight would be pushed to January 2023. Currently, the first Dream Chaser spacecraft will berth to the International Space Station no earlier than December 17, 2023. Not long ago August was the expected launch date however it was recently pushed back to late this year. Since Dream Chaser is only a spacecraft, it requires a dedicated launch vehicle to get into orbit. For the initial mission, ULA’s new Vulcan will be responsible.
Completed Tests
While Dream Chaser has not yet been to space, the company has completed a host of different tests trying to prepare this spaceplane. For example all the way back in 2013, the first free-flight occurred. Here, the test vehicle was released from the helicopter and flew the correct flightpath to touchdown less than a minute later. However, just prior to landing, the left main landing gear failed to deploy resulting in a crash landing. The vehicle skidded off the runway in a cloud of dust, but was found upright with the crew compartment intact and all systems inside still in working order. Unfortunately Sierra Space cut the video right before Dream Chaser touches down on the runway. Around 4 years later in 2017, the Dream Chaser Test Article was released from an altitude of 3,700 m and successfully landed at Edwards AFB.
In addition, in early 2014, Sierra Nevada completed its wind tunnel testing. The wind tunnel testing involved analyzing the flight dynamics characteristics that the vehicle will experience during orbital ascent and re-entry. Wind tunnel testing was also completed for the Dream Chaser Atlas V integrated launch system. These tests were completed at NASA Ames Research Center at Moffett Field, California, CALSPAN Transonic Wind Tunnel in New York, and at NASA Langley Research Center Unitary Plan Wind Tunnel in Hampton, Virginia.
All of these tests were using a Dream Chaser test article named Eagle, an Engineering Test Article (ETA) used for captive carry and atmospheric drop tests. The company has another test article named Ascension that has yet to be tested. Then there is Dream Chaser Tenacity which is the first space capable test article that will be launched late this year. Finally, images released by the company revealed DC102 or another crewed variant early in its development.
The originally planned Dream Chaser Space System is a human-rated version designed to carry from three to seven people and cargo to orbital destinations such as the International Space Station. It was to have a built-in launch escape system and could fly autonomously if needed. Although it could use any suitable launch vehicle, it was planned to be launched on a human-rated Atlas V N12 rocket. Its reaction control system thrusters burned ethanol-based fuel, which is not an explosively volatile material, nor toxic like hydrazine, allowing the Dream Chaser to be handled immediately after landing, unlike the Space Shuttle.
As of 2020, the Sierra Nevada Corporation says it still plans to produce a crewed version of the spacecraft within the next 5 years. The company says it “never stopped working” on the crewed version and fully intends to launch it after the cargo version, and is still committed to the crewed version as of 2021. In 2021, Sierra Nevada Corporation reported that it received a $1.4 billion investment in Series A funding, which it will use to develop a crewed version of Dream Chaser and fly astronauts by 2025. Not long ago the company hinted at a crewed dream chaser with an image. The unique dream chaser was labeled DC-201 and featured a twin-tail, fixed-wing design.
The company describes Dream Chaser as a multi-mission vehicle capable of supporting a variety of LEO needs. It can be customized for both domestic and international customers via vehicle configuration, launch site, destination, landing site, duration, and a host of other variables. Sierra Space has entered into agreements with multiple international space agencies. Together they are developing technologies, applications, and missions for Dream Chaser-based space systems. For example, the company has made deals with different companies and governments getting access to landing sites around the globe. In the future, the plan is to utilize this worldwide access and offer it as a service on Dream Chaser for both crew and cargo missions.
Conclusion
Dream Chaser is hoping to change how we access space with a rapidly reusable low-g spaceplane design. With the maiden flight scheduled to happen this December, we are not far away from watching Tenacity take flight for the first time ontop of Vulcan. We will have to wait and see how it progresses and the impact it has on the space industry.