After Vulcan’s first launch early this year, the plan was for Dream Chaser to be the second payload sometime in the summer. That being said, recently it’s become clear that Sierra Space needs more time to complete testing and final prep before they are ready to integrate the spaceplane with Vulcan. Interestingly, rather than just waiting for Dream Chaser to be ready, ULA has decided to launch without them.
Specifically, they decided they’re instead just going to launch a mass simulator in order to ensure Vulcan is certified in a timely manner. However, because Dream Chaser is missing its ride to space, the next available Vulcan could be well into 2025 based on ULA’s current manifest. Here I will go more in-depth into this delay, ULA’s rush for certification, final spaceplane testing, and more.
Missed Its Ride
Last month in May, Sierra Space’s uncrewed spaceplane arrived at NASA’s Kennedy Space Center in Florida ahead of its first flight to the International Space Station. At the time of arrival, the remaining pre-flight activities at Kennedy included acoustic and electromagnetic interference and compatibility testing, completion of work on the spaceplane’s thermal protection system, and final payload integration. Currently, the first Dream Chaser, Tenacity, is still in Florida undergoing final testing among other flight prep. The plan to launch it this summer was pushed back to an indefinite date with officials saying they expected the launch sometime late this year. New information suggests this might not be the case at all.
Recently Tory Bruno, CEO of ULA said in a quote, “We have been informed by Sierra Space that they feel that they have significant risk towards making the mid-year flight date. They told us they will step aside in order to support our critical national security space missions that will come afterwards.” In this case, he went on to mention that they will now be launching a mass simulator which was built in case the first mission payload, the Peregrine Moon Lander, wasn’t ready in time.
This all has to do with United Launch Alliance’s Vulcan certification. The U.S. Space Force requires two Vulcan flight tests in order to certify the vehicle for a long list of future missions. Once ULA launches a second time and gets Vulcan certified, they then can begin launching somewhat frequent national security missions with large price tags. This is the main reason they decided not to wait on Dream Chaser and instead just launch a large inert payload.
Where the problem comes in isn’t necessarily Dream Chaser missing this second Vulcan but the rocket’s subsequent schedule being jam-packed. Assuming the rocket is certified after the scheduled launch in September, the company said it wants to launch two Space Force missions, designated USSF-106 and USSF-87, before the end of the year. This busy schedule combined with limited Vulcan hardware could push Dream Chaser back quite a bit.
Vulcan is expendable and requires new construction for each vehicle. The second Vulcan just arrived at the Cape and the others are making progress in the factory. In the past few months, we have seen quite a few BE-4 engines rolling into ULA’s factory along with multiple Centaur upper stages and other Vulcan components. Just over a week ago Tory Bruno tweeted that all the BE-4s for Vulcan’s 2024 launch manifest had been delivered to the company. All this being said, it looks like the next three Vulcan launches will not be with Dream Chaser. This pushes it back toward early 2025 if not later that year. In a statement to SpaceNews Sierra Space said, “As a defense-tech prime, we understand how important ULA’s Cert-2 mission is to the criticality of national security and our launch partner’s schedule. We are working closely with ULA to identify the next available launch date.”
As far as other options, back in 2019, it was announced that all six Dream Chaser CRS-2 flights would be carried into orbit by ULA’s Vulcan launch vehicle. In other words, Dream Chaser will launch on a Vulcan even if it means waiting a bit longer for ULA’s busy launch manifest. It’s also important to point out that Dream Chaser Tenacity is still not ready yet and simply needs more time before any launch vehicle can send it into space for the first time.
Dream Chaser Tenacity
The last Space Shuttle launch was over a decade ago in 2011. Even though Tenacity is also a spaceplane and is often compared to the Shuttle, in a few important ways it’s very different. The Dream Chaser spaceplane is a multi-mission vehicle meant to support 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 is quoted saying, “Tenacity represents an uncrewed spiritual successor to the space shuttle, and at 30 feet (9 meters) long, it’s roughly a quarter of the total length of the space shuttle orbiters. Tenacity’s pressurized volume is 33 cubic meters (including both the spaceplane and the cargo module). This makes the spaceplane more sustainable and easier to maneuver, but it also assists with gentle 1.5g runway landings – ideal for fragile cargo.
As for the heat shield, thousands of unique individual tiles are attached to each portion of the spaceplane. The difference between black and white is an additive to the outer glass coating which helps balance heat absorbed. Each tile is unique in design, and differs in size, shape, thickness, and density. In the past, the Space Shuttle used tens of thousands of tiles which presented a few issues. However, Sierra Space is quoted saying, “SNC engineers have been able to update the TPS tiles from what was used during NASA’s shuttle program with more innovation, better technology, and utilizing lessons learned. They use more modern manufacturing techniques to increase strength and reduce cost. Another difference between the tiles is Dream Chaser tiles are about 10 inches by 10 inches, while those on the shuttle were six inches by six inches. Dream Chaser tiles are stronger and lighter weight than those used during the shuttle program and meet all Micro-Meteroid Orbital Debris (MMOD) requirements to ensure safe entry, descent, and runway landings for crewed or cargo missions. These among other changes are intended to make the tiles even more reliable and easier to refurbish.
In practice, installing the first heat shield on Tenacity took some time. To put it in perspective, tile application began around four years ago in June of 2020. At that time SNC, the parent company of Sierra Space tweeted saying, “Our Dream Chaser® spaceplane is starting to get the black & white color that’s seen in renderings! We’ve started bonding the Thermal Protection System tiles to the vehicle.” This process would continue over the next few years until its completion late last year.
While this is the first physical test article and tile application, which would partially explain the amount of time needed to install the heat shield, it still took over two years. In reality, if Sierra Space was installing an entire shield today, it would likely be a lot faster as they now have experience. In addition, it’s possible they took their time and matched the tile installation with the general production of the test article. Whatever the case, installing 2000 plus unique tiles will always be a time-intensive process because of its complexity and importance. In addition, assuming the first launch is successful and Dream Chaser Tenacity lands on a runaway, this will give the company great insight into the time needed to refurbish the tiles. The Space Shuttle had a very slow turnaround time due to the amount of work inspecting and replacing various tiles. Something Sierra Space is trying to improve on.
One of the final steps before launch is adding a few tiles to missing locations around the spaceplane. Specifically, they said one of the remaining pre-flight activities involves the completion of work on the spaceplane’s thermal protection system. Images and videos of Tenacity highlight that a majority of its tiles are installed however some are still missing. This likely has to do with testing requirements and those tiles being installed when the vehicle is officially ready to launch.
As far as actual progress goes, over the past several months, Dream Chaser has undergone intense shock, vibration, and thermal vacuum testing at the Armstrong Test Facility in Ohio. These tests not only were meant to check Tenacity’s capabilities in space, but also the initial journey. For example, in December, the test teams conducted shock tests with Sierra Space’s launch partner United Launch Alliance (ULA), using the flight separation system that will deploy the spacecraft from the upper stage of ULA’s second Vulcan Centaur rocket. Officially, back on May 9th, they announced the successful completion of Dream Chaser’s Neil Armstrong Test Facility environmental test suite. With that done, the vehicle along with Shooting Star, the spacecraft attached to the back, were packaged up and sent to Florida. Upon arrival at NASA Kennedy, teams moved Tenacity to the high bay inside the Space Systems Processing Facility. As partially mentioned before, the remaining pre-flight activities include acoustic and electromagnetic interference and compatibility testing, TPS completion, and final payload integration. Something we can look forward to seeing in the coming months.
Conclusion
Sierra Space is going to have to wait a bit longer before both Tenacity and a new Vulcan is ready for to launch. With the spaceplane not being ready in time for the Cert-2 launch, a number of missions are now taking priority, possibly pushing Teancity’s launch back to early to mid-2025. We will have to wait and see how it progresses and the impact it has on the space industry.