A Closer Look At Dream Chaser’s First Flight
Dream Chaser is a modern spaceplane getting close to its maiden flight. The initial variant is an uncrewed version that will carry cargo to the International Space Station and dispose of trash on its way back. As its mission gets even closer, Sierra Space has begun training both mission controllers and even astronauts on future ISS missions to understand how to complete this mission.
This maiden flight is a demonstration mission and will be the first test of some of Dream Chaser’s different features. Between launch and landing, the mission includes a long list of different objectives and milestones that if met, will determine how well this spacecraft performed and what its future may look like.
Sierra Space has confirmed work on a crewed variant which will likely be the future of this platform. This being said, until an uncrewed variant has flown successfully multiple times, we won’t see crew using Dream Chaser to get into LEO and back. Here I will go more in-depth into the first mission’s flight profile, new launch date info, the importance of this mission, and more.
Flight Profile
Dream Chaser is only a spacecraft, not a launch vehicle, so it needs some help in order to reach orbit. For this maiden flight, the launch vehicle is United Launch Alliance’s brand new Vulcan Centaur. This rocket was supposed to attempt its maiden flight a long time ago but has run into a few different delays. While some of the initial testing went well, the upper stage of the rocket is currently in the company’s factory undergoing necessary upgrades. 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.
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 berthing with the ISS, the spaceplane will use its various thrusters to position itself on the exact path. The main run initializes at 119 km below and behind the ISS. Through a carefully choreographed set of “burns,” Dream Chaser will approach and intercept the earth radius vector directly below the ISS. With built-in holds at several points along the way, Dream Chaser will gradually climb up to a capture point that is 11.5 meters below the space station’s Japanese Experiment Module. When Dream Chaser is at the capture point, the ISS crew moves the robot arm into position and grapples the spacecraft. This can take approximately six hours from start to finish in training simulations, and in most cases, is not problem-free.
Once attached, 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.
Launch Update
Before any part of that mission profile can take place, a few things need to happen. This includes the first Vulcan successfully lifting off and Sierra Space finishing Dream Chaser Tenacity. It’s been quite a long time since the company gave us an update on the exact progress of Tenacity. The last time we saw the spaceplane they were attaching the thermal tiles. This being said, all the way back in January of this year the company was quoted saying, “The first Dream Chaser, Tenacity, is nearing completion and will subsequently ship to NASA’s Neil Armstrong Test Facility in Cleveland, Ohio, for final space environmental testing ahead of its first mission to the ISS later this year.” By now it seems likely that Vulcan will be the aspect responsible for any delays to come.
While we don’t have access to an official accurate launch timeline for the spaceplane, we got a hint from the company in a recent report. Over the last few days, Sierra Space hosted its third official training of NASA astronauts to learn the innerworkings of Dream Chaser. The three astronauts are members of the upcoming NASA’s SpaceX Crew-8 mission to the International Space Station, which is currently slated to launch no earlier than February 2024. Sierra Space was quoted saying, “During their planned six-month stay, Dream Chaser is scheduled to make its maiden voyage to deliver cargo to the ISS as part of NASA’s Commercial Resupply Services-2 (CRS-2) contract. This suggests that closer toward the middle of next year is when we could see Dream Chaser docked to the station.
We are pleased to train the crew that will be on board the International Space Station for Dream Chaser’s first cargo resupply mission,” said Sierra Space CEO Tom Vice. “These astronauts underwent an extensive training curriculum to prepare them for how to interact with our spaceplane when it berths with the ISS. We are honored to join NASA’s cargo resupply team.” During this latest set of training, the astronauts received 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.). The astronauts ended Part 1 with a much deeper understanding of Dream Chaser’s hardware once it is berthed with the International Space Station.
They also learned some of their required actions as Dream Chaser makes its approach and officially berths with the International Space Station. Topics included a full review of the timeline, profile and procedural operations of the high-level system configuration involved in this critical part of the mission. Its important to point out in relation to the future schedule of Dream Chaser, that early last month Sierra Space was training some of Crew 7. This launch will obviously take place before Crew 8 and highlights that Sierra Space really is not exactly sure when Dream Chaser will dock based on a few delays. At the time they were quoted saying, “Crew-7 might be the team onboard the ISS when Dream Chaser berths with the station for the first time.”
In reality, it will likely just come down to Vulcan as far as launch delays and when this first mission lifts off. Due to the fact that Dream Chaser will launch on the second Vulcan mission and not the first, they need the maiden Vulcan and its various payloads to successfully lift off first. ULA CEO Tory Bruno recently gave an update and highlighted that the upper stage repairs are underway and making fast progress. He also expressed his confidence in launching the first Vulcan this year. 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, with the first Dream Chaser flight being the second Vulcan flight in late 2021. Obviously, some things have changed since then however a lot of the future flights still plan to use a Vulcan. Ideally, after these initial delays, Vulcan will be capable of launching on time for the foreseeable future.
Conclusion
Dream Chaser has somewhat of a complex flight profile on its first mission to the ISS. This involves the initial launch on Vulcan, rendezvousing with the station, cargo delivery, and Earth reentry, just to name a few. We will have to wait and see how it progresses and the impact it has on the space industry.