Mission Control: What Does the Rendezvous Simulation Look Like?

Sierra Space and NASA conduct a docking simulation with Dream Chaser and the International Space Station.

They weren’t kidding: practice does make perfect. That age-old sentiment holds true in everything: sports, the arts, and even space exploration.

If we are to enter the next period of human innovation, space companies need to get the technology right – and that doesn’t happen without meticulous and consistent practice.

At Sierra Space, we have more than three decades of spaceflight heritage with applications, and we’ve learned a thing or two (or two hundred) about practice simulations.

As we develop the first-ever winged commercial spaceplane, Dream Chaser®, we’re dedicated to getting it just right. That starts with realistic simulations for every aspect of the practice, including rendezvous and berthing at the International Space Station (ISS).

When two spacecraft meet while in orbit, precision is key. The trajectory and timing need to be perfect, as do the complex mathematical calculations that determine the position and speed of both spacecraft.

That’s why we practice every part of the process in excruciating detail. Just recently, we conducted a comprehensive rendezvous test with NASA to simulate the docking procedures of the Dream Chaser® spaceplane. The Joint Multi-Segment Training (JMST) was considered a success by both Sierra Space and NASA. The second JMST will be held on July 21.

But what does one of these rendezvous simulations look like?

Today, we’re walking you through the process from start to finish.


Rendezvous Simulation Roles

First things first: who’s at the helm when we conduct these simulations?

Our team of experts is led by an experienced Flight Director, similar to the setup at NASA’s Mission Control Center. This leader is responsible for overseeing the entire team of mission controllers, as well as all aspects of the mission from launch to landing.

During the simulation, the Flight Director maintains constant communication with their team and NASA, ensuring the spacecraft remains on course, as well as preparing for any changes or updates to the mission plan.

In both simulations and real rendezvous berthing instances, the Flight Director is the direct line to mission control. Therefore, they’re heavily involved in every practice scenario and must be trained to make quick, informed decisions under high pressure.

The rest of the simulation crew assists under the supervision of the Flight Director and helps them prepare for every possible mishap or complication.

Sierra Space and NASA conduct a docking simulation with <span class=Dream Chaser and the International Space Station.” width=”960″ height=”640″ />


The ‘Day-Of’ Timeline

The training team arrives early on sim day to initialize and configure the simulator. All of the flight controllers then set up their consoles and prepare to brief the Flight Director on the circumstances, as they would do on a real shift during a real mission.

The run initializes at 119 km below and behind the ISS. Through a carefully choreographed set of “burns,” the simulated Dream Chaser approaches and intercepts the earth radius vector directly below the ISS.

With built-in holds at several points along the way, Dream Chaser gradually climbs 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.

Every rendezvous simulation provides the opportunity to encounter and address potential problems for the Dream Chaser. Except for the launch and landing day, rendezvous day is considered a ‘dynamic’ operation – and safeguarding the astronauts aboard the ISS is of paramount concern.

The more space companies like ours can learn about potential risks via a simulation, the better we can protect real lives up in space someday.

At the end of the day’s simulation, the team debriefs all that transpired, including what went well and the opportunities to learn and improve. Then, it’s back to the drawing board to prepare for the next simulation.


Differences Between Flight and Simulations

Anyone who knows anything about space travel knows that practicing something in simulation is always different from practicing it in a real flight.

So, what are the core differences between a rendezvous simulation and the real deal? And how do we account for them?

For example: in real-life missions, things often fall behind – and even the slightest adjustment to timing during rendezvous can mean a world of difference.

Although we cannot predict every outcome in space, we can do everything in our power to ensure that timelines and procedures are met with precision. A key part of simulations at Sierra Space is ensuring that the core events are never missed.

Ultimately, the Sierra Space Flight Operations team throws various malfunctions and scenarios at the space crew and controllers to make them sharper. When unexpected (and expected) issues arise in space, everyone needs to be as prepared as possible to react and adjust.


Learn More About the Sierra Space Process

Our spaceplane Dream Chaser stands to become the ultimate space vehicle – one that will provide valuable cargo services to the space station and further the future of the space economy.

However, we know we’re not the only ones out there thinking about this future. We’re proud to be among a small community of public and private space companies that are bringing us closer to the stars.

For the sake of our spaceplane and vital cargo, we know we cannot afford to mess up – even on the first launch. That’s why we take simulations seriously.

Rendezvous is only one part of Dream Chaser’s mission. As we continue our practices, we will conduct simulation exercises for every aspect of the mission to ensure the highest possible chances of success and safety.


Are you thinking about the next frontier as much as we are? Look into our growing career opportunities at Sierra Space. You can also learn more about our objectives and innovations by exploring our website.

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