After years of work, Sierra Space’s first Dream Chaser reusable spaceplane is almost ready to fly. The vehicle’s next step is a trip to NASA’s Neil A. Armstrong Test Facility in Ohio ahead of its first launch at the Kennedy Space Center currently scheduled for no earlier than March 2024.
NSF was invited as part of a media event inside the company’s facility in Louisville, Colorado, to see the first flight article named Tenacity prior to departing for environmental testing.
Dream Chaser is a reusable spaceplane that contains an expendable cargo module. That module also houses the vehicle’s solar panels. It was selected as part of the Commercial Resupply Services 2 (CRS-2) contract by NASA, joining SpaceX and Northrop Grumman to bring supplies to, and in this instance from, the International Space Station (ISS).
The plane is then designed to land on a runway. In particular, ISS missions will land at the Launch and Landing Facility, formerly the Shuttle Landing Facility, located at NASA’s Kennedy Space Center in Florida and currently operated by Space Florida.
Re-Flying Dream Chaser
Sierra Space’s CEO Tom Vice said the company expects to be able to turn Tenacity around in six months following its landing, seeing it fly again aboard United Launch Alliance’s new Vulcan rocket.
“We’d like to turn the vehicle and be prepared to fly potentially twice next year, but again, that’s really dependent upon NASA,” Vice said. “NASA has a manifest, when they can take the cargo, when they need cargo.”
Sierra Space is currently contracted for seven missions under the CRS-2 contract and is in discussions for potentially more flights.
However, Vice says one of the benefits to Dream Chaser is that it can be used as its own orbiting science platform as well, and can spend six months in orbit undocked from the ISS.
“We fly [Dream Chaser] as a service,” Vice said. “So we could fly them for other government agencies… Whether it’s flying it for a commercial customer that wants to do early drug clinical trials on a free-flying mission, or it’s another part of the US government that would like to have a mission for other purposes, it’s set up to be able to do those.”
Dream Chaser’s first ISS mission was originally planned for 2021; however, the company has faced many delays, including issues with the supply chain during the COVID-19 global pandemic.
As a result, Vice said Sierra Space has tried to counter those challenges by building as many components on-site as possible.
“Where we saw a critical need was, obviously, we built all of our own thrusters,” Vice said. “We’re now doing all of our own thermal protection systems. We built 90 percent of all of our own harnesses. So we really have thought about where were their bottlenecks, and we’ve eliminated those bottlenecks by bringing them to work in-house. And what we found almost immediately is we can move faster, higher quality products, much cheaper, and we don’t have that risk.”
The company has even built its own solar panels on-site to help provide electricity to its buildings.
An additional concern has been delays in working with NASA and other partners involved with the ISS. There are strict requirements that must be met by any vehicle visiting the orbiting laboratory, including making sure the software onboard Dream Chaser can communicate with the software used on the ISS.
“It’s a big deal to approach the ISS, and so we’ve taken that very seriously for a long period of time, and we do a lot of joint activity with NASA just to make sure we don’t have that problem,” Vice said.
The company is also still waiting for a license from the Federal Aviation Administration (FAA) to perform a commercial reentry. The FAA released the first proposed project information in 2021 for that license.
Vice said they are working closely with the FAA and are continuing to exchange information and have continued discussions. However, he’s aware there are a lot of launches and claims there are not enough resources.
“The FAA is really busy, and I think one of the things I always advocate is the FAA needs more resources, and we spent time in Congress trying to get the FAA more resources because they could really use it,” Vice said. “Space is growing fast. As you can imagine, SpaceX is waiting, Blue Origin is waiting, lots of rocket companies are waiting, and of course, we’re waiting… so they could use additional resources.”
Prior to its upcoming testing in Ohio, the vehicle went through some of its own testing in Colorado. That included the first deployment of the wings.
Dream Chaser’s wings fold to allow the current cargo variant to fit within Vulcan’s 5.4-meter fairing. The wings are unfolded in space and are used for control authority upon returning to Earth’s atmosphere. However, once in the atmosphere, the primary source of lift is the body of the spacecraft and not the wings.
Similar to the space shuttle’s payload bay doors, special equipment is needed to test these systems while on the ground.
“You have to be very careful in a one G environment because they are meant to deploy it in 0 G. A lot of mechanisms are on top of it to make sure you deploy it without breaking anything.”
Vice also noted the increased interest in hypersonic vehicles, and said, “Wings are back!”
“You know, we’re going to be flying Mach 25 on Dream Chaser every time we enter the atmosphere, and we’re going to collect probably the most amount of data on hypersonic vehicles,” Vice said, noting that this is in addition to creating a vehicle that is also stable aerodynamically during supersonic, transonic, and subsonic phases of flight.
Another development that has been years in the making is the on-orbit propellants the vehicle will use. Many spacecraft use hypergolic propellants, such as hydrazine, which ignites when coming in contact with an oxidizer, removing the need for a spark or additional igniter.
While used for many years, they are toxic to humans. Sierra Space is using a mixture of Rocket Propellant 1 (RP-1), which is a refined form of kerosene, along with hydrogen peroxide, for maneuvering the vehicle.
“We wanted to have a fuel system that was green, instead of using hypergolic, so that we could land it at a runway and walk up to the vehicle without being in hazmat suits,” Vice said.
He did note that designing the system contributed to some of the company’s delays.
While Tenacity and the currently-under-construction second vehicle are designed solely for cargo missions, future missions are planned that can carry three to six people into orbit and back. That’s part of why Vice said safer fuels are so important.
“Think about it, we could land Dream Chaser at the Paris Air Show. A few minutes later, it cools down, six people get out and walk into a chalet, they’re not wearing hazmat suits,” Vice said. “Then it’s just waiting for [the vehicle’s heat shield tiles] to cool off and it doesn’t take long.”
Vice said a crew variant isn’t expected until 2026. The crewed version will feature an abort system with a different fuel system, but no details on this system were offered.
While at Sierra Space, NSF saw what will be the company’s second spaceplane.
Vice said a lot has been learned from building Tenacity. These lessons have reduced the number of issues on build two by 80%, resulting in quicker assembly and lower cost. Vice estimated that Tail 2 is roughly 24 months behind Tenacity.
A look at the shell of what will be Sierra Space’s second, yet-to-be-named Dream Chaser vehicle. (Credit: Trevor Sesnic for NSF)”Things that used to take weeks and months and years to build, we now build in a fraction of the time,” Vice said. “We do the work that we’re doing on next-generation thermal protection systems here, material systems is done here, so there’s a lot done here.”
The design of the cargo variant also features a cargo module placed behind the vehicle, which currently is not reusable and is designed to burn up on reentry. The company aims to launch 30 missions using its first two flight vehicles, each of which requires a brand-new module.
Sierra Space is now working on a product known as Ghost. The system would act as an inflatable ablative shield that would protect the cargo module before parachuting down to a designated location to be recovered. Economically, Vice said it would be a game changer to be able to reuse the cargo module and vehicles 15 times each.
“Even on [SpaceX’s] Dragon, you know, the trunk of Dragon gets burned up every time,” Vice said. “We took one step back and said, you know, can we reuse the entire system? And again, that would change everything.”
The company plans to start with small-scale tests before scaling up to the larger size needed for the cargo module.
While an exact date has not been publicly released, Tenacity will soon make the journey from Louisville, Colorado to the former Plum Brook facility, now the Neil A. Armstrong Test Facility, in Sandusky, Ohio.
Once there it will be placed inside the facility’s large thermal vacuum chamber for environmental testing. Once completed, the vehicle is then expected to move to the Kennedy Space Center for launch preparations.
While no launch date has officially been set, Sierra Space expects to launch no earlier than March 2024, using ULA’s second-ever Vulcan Centaur launcher.