Dream Chaser Prepares For Its First Flight To The ISS
Despite different delays, the first Dream Chaser mission is still coming up fast and with it are more frequent updates from the company. The first mission will see the spaceplane dock to the International Space Station and deliver a significant amount of cargo. However, this process requires a crew to board the spacecraft and at least know how to operate and navigate the various systems.
Recently crews that will soon launch on the SpaceX Dragon got a crash course on the Dream Chaser cargo module. Here we got a much better idea of the interior and what we can expect to see on launch day. This comes in addition to more updates regarding Tenacity’s heat shield which has been a major focus of the company for a while now.
If successful, there will be another option within the space industry for consistent cargo transport and future crew capability. Here I will go more in-depth into the recent Dream Chaser astronaut training, the interior of this spaceplane, what to expect in the coming months, and more.
Dream Chaser Training
Since Dream Chaser Tenacity is an uncrewed spacecraft meant to transport cargo, the agency and Sierra Space can afford to fill it with supplies even on its first test flight. This means however that if everything does go well and it docks to the ISS, teams will need to access and understand the hardware.
Just days ago on the 23rd, Sierra Space announced that it achieved another significant milestone in the journey to the first flight of Dream Chaser. The company hosted its first-ever official training for astronauts from NASA and JAXA to learn the inner workings of the world’s first commercial spaceplane. The astronauts, one from the United States and one from Japan, are two members of the upcoming SpaceX Crew-7 mission to the International Space Station (ISS). During their planned six-month stay, Dream Chaser will make its maiden voyage to deliver cargo to the ISS as part of NASA’s Commercial Resupply Services-2 (CRS-2) contract.
At the time Sierra Space CEO Tom Vice commented “The astronaut training is another important milestone as we complete the final preparations for Dream Chaser’s first mission. Our team provided a comprehensive training experience for these Crew-7 members to prepare them for when Dream Chaser berths at the ISS” he said.
Specifically, Sierra Space compiled an eight-hour training session that took place on March 7 at the company’s, Colorado facility. Company specialists conducted the training, which was divided into four sections. Parts 1 and 2 were classroom training, while Parts 3 and 4 involved a full-size mock-up of Dream Chaser. During the classroom portion, Sierra Space members gave the astronauts a full briefing on Dream Chaser. Topics covered included systems identification and function, mission profiles (from launch and rendezvous to reentry and landing), crew interfaces and operations (i.e., types of cargo, how to load/unload, etc.). At the end of Part 1, astronauts walked away with a full understanding of the hardware they will encounter on Dream Chaser once it is at the ISS.
During part 2, they covered required actions as Dream Chaser makes its approach and officially berths with the ISS. Sierra Space employees carefully reviewed the timeline, profile and procedural operations of the high-level system configuration involved in this critical part of the mission. Moving on to part three, the astronauts moved into a full-size mock-up of Dream Chaser. As they walked through the vehicle, Sierra Space employees identified hardware/systems and taught the astronauts how to operate and/or interface with each one. The astronauts also learned vehicle ingress/egress procedures, as well as discussed off-nominal scenarios.
Finally, during part 4, the astronauts learned how to properly and safely install/remove cargo from Dream Chaser, using the same procedures and operational tools as they will on orbit. They practiced with numerous restraints (i.e., straps, beams, etc.), identified hazards associated with cargo operations and ran scenario drills. In a quote, they said, “This was probably the most important lesson of the day because the whole point of Dream Chaser coming to the ISS is to deliver cargo.”
As partially mentioned prior, these astronauts are launching on SpaceX’s Crew 7 mission not long from now. This SpaceX launch is scheduled to lift off a bit over two months from now on August 17th. While Dream Chaser Tenacity isn’t set to launch until around December, the astronauts apart of this crew mission will be at the station until early 2024. This gives them enough time to catch Dream Chaser during its window at the station. This assumes however that Tenacity and Sierra Space along with its dedicated launch vehicle are ready by late this year. The most recent update was only days ago in a tweet from Sierra Space, where they said, “Attaching tiles to Dream Chaser, Tenacity, is a highly intricate process. Do you know why both black and white tiles are used?” This included an image of the team attaching a large portion of tiles to the side of the spacecraft. They answered their question, “Both versions of the tiles are used to help balance the heat absorbed on-orbit and the heat that the spaceplane will need to survive on reentry. The areas in black will have the hottest temps on reentry while the white tiles are more reflective and will be cooler.
Flight Profile
As this first mission approaches, we are learning more about the flight profile and what exactly will happen on launch day. The launch vehicle is United Launch Alliance’s brand new Vulcan Centaur. This rocket was supposed to attempt its maiden flight months ago but has run into a few different delays. Most recently the company had to hold off on the first static fire after the timing and response of the BE4 ignition system didn’t look right. In relation to Dream Chaser, the first mission is meant to happen on the second Vulcan flight which could cause some delays.
Either way, this is the current plan for Tenacity’s maiden flight. In this case, once the vehicle arrives at the site it will integrate with Vulcan. At this stage, Dream Chaser will have its wings folded in allowing it to fit within Vulcan’s fairings. In addition, the spaceplane will be elevated by the Shooting Star service module which will also be used on this first test flight. In addition to carrying cargo, the Shooting Star module includes solar panels that supply up to 6 kW of electrical power. It also supplies active and passive thermal management; provides Dream Chaser translation & rotation capability via six mounted thrusters; and supports berthing or docking (in different configurations) to the ISS. This is important and connects to the recent astronaut training because access from the ISS to Dream Chaser will involve crew passing through Shooting Star and through a hatch that separates Shooting Star from Dream Chaser.
Once on the launchpad, Vulcan will undergo a series of checks to make sure everything is ready for launch. Finally, the two BE-4 engines will ignite in addition to the SRBs with Vulcan lifting off. Not long after the rocket takes off the boosters will be expended and the main BE-4 engines will cutoff. The two stages will then separate and the upper stage will ignite its two RL10C engines. The payload fairings will eventually jettison revealing Tenacity and its Shooting Star module.
At this point, the spacecraft will detach from the upper stage and then unfold its wings. Between then and docking with the ISS, the spaceplane will use its various thrusters to position itself on the exact path. The final approach will see Tenacity backing up toward the station as the Shooting Star side is what will dock with the ISS. Once docked, crews on the ground and in the station will make sure everything looks good before they open the hatch and access the cargo. Years ago it was announced that an expendable Shooting Star cargo module would be part of the Dream Chaser cargo system for CRS-2 flights. The module is a long attachment to Dream Chaser that will allow the spacecraft to carry an additional 10,000 pounds (4,500 kg) of pressurized and unpressurized cargo to ISS. This means that Tenacity will have quite a lot of cargo abroad. Likely not the full capacity but enough to support the station and its astronauts.
Tenacity is expected to stay docked with the ISS for around two to three months before it’s time to leave. At this point, crews onboard will load the spacecraft with any disposable items. The Shooting Star module also supports the disposal of unwanted cargo by burning up upon re-entry. When this is complete and the hatch is closed, Dream Chaser Tenacity will detach from the station and then separate from its Shooting Star module. Dream Chaser will then attempt one of the most difficult mission objectives during reentry. Assuming everything goes well it will make it through the atmosphere in one piece and begin descending through the atmosphere. Finally, Tenacity will attempt a landing on a runway to complete the first Dream Chaser CRS-2 Cargo mission.
Conclusion
Dream Chaser Tenacity is set to lift off for the first time ever in about 6 months from now. This program has been under development for decades now and is finally about to test its capabilities. If successful we can expect to see much more launches and even a crewed variant in the future. We will have to wait and see how it progresses and the impact it has on the space industry.