So far this week, we have discussed the build-up to a hot fire.
Today, we’ll talk about the roles we play in the process.
In the bunker, a wall of video monitors gives the test crew excellent situational awareness. Cameras are placed to accommodate the specific test and points of interest. If needed, high speed and infrared cameras gather additional data. And on the radio, crew members are called-out by their positions.
Crew positions, roles and responsibilities for each hot fire include the following:
Control:Runs the control box and actually commands the rocket engine to fire.
DAQ:Runs the Data AcquisitionUnitwhich records data from instruments on the stand. They are also responsible for displaying the data for instant review by the test crew after the test.
Red Team: This team directly interacts with the test stand while everyone else is inside the bunker. They return to the bunker during pressurization and during the actual hotfire.
Test Czar: This individual is in charge of the test and has the final say on go / no-go conditions, and sets the test objectives and parameters. Acts as a safety net for the rest of the team, considering all possible risks before giving the green light.
Spotter: Acts as an additional safety check and spends most of the day seated on top of the bunker to keep an eye out for anyone approaching the test site. The spotter makes sure that the area down range of the rocket engine remains clear, and is only called-in just before the actual test.
Video: In charge of setting up and maintaining all the video feeds from the test site. The objective is to make sure to record all of the video during press, chill and hotfire.
Checklist:Acts as the pace setter for the test. By reading the checklist methodically and accurately they set the tempo for the test day. The checklist contains all of the commands for all of the other positions except the Test Czar.
Safety: The primary safety officer in charge of ensuring all protocols are followed for the whole test. Safety may stop a test at anytime for any reason if they feel the crew or the uninvolved public are at risk.
On Tuesday we told you about preparing to roll out for a hot fire. Wednesday was the journey to the test stand.
Today, what happens when we arrive …
Once we are at the test site, there is a flurry of activity. We attach the truss and fuselage to the test stand, a concrete slab rated for up to 80,000 lbf of thrust. It is a monster of a concrete pad, and contains various types of mounting brackets that can be used for a range of engine test stands.
Next to the test stand is our bunker. It is an old WWII ammunition storage bunker built by the US Navy Seabees for the Marine Corps, right around 1942. It is capable of withstanding the explosive energy of 435,000 pounds of TNT.
Shot atop the XCOR bunker, this photo shows the test stand in the foreground, and a bunker similar to ours in the background.
The bunker has very thick concrete walls and is covered by yards of earth. As a result it is cool in the summer and warm in the winter, with six inch-thick steel doors. It would make one heck of a man cave!
The interior of the XCOR bunker
We purposefully do not trick it out, because our philosophy is to have one culture at XCOR, not to have different mini-cultures grow up inside the company such as “the guys in the test bunker” or “those test stand fabricators” or “the composite team”. Everyone is one big team, and we all enjoy the simplicity of a day in the bunker!
As all of our test equipment is portable, very little remains out at the test bunker. When we arrive, the test stand is bolted to the test pad, cables are unreeled from the pad to the bunker, cameras are set up, and computer gear is electrically connected. Once everything is in position, gas and fluid cables for pressurization and valve control are attached and the “control room” inside the bunker goes live. The whole team is ready to ”get on checklist”.
XCOR senior shop mechanic Mike Laughlin checks a high-pressure hose fitting in preparation for a hotfire test.
Tomorrow we will show you the roles and responsibilities for the test, and you can decide what role you want to play!
The XCOR caravan makes its way past the “bone yard” for another hot fire.
Yesterday we went through initial morning activities that surround the day of a hot fire test, rolled out the flight weight fuselage and engine truss. We started to fuel LOX and kerosene around 7AM.
Cut to two hours later…
Around 9AM, after the kerosene and LOX fill is complete, and after running through check lists and various pre-rollout processes, we tow the engine test stand and truss out to the XCOR Test Bunker on the other side of the Mojave Air and Space Port.
The caravan of vehicles include the F-150 pickup truck with which we tow the test stand, a Hummer we use to tow the gas bottle trailer (a rolling stand filled with high pressure gases, such as helium and nitrogen, which we use for tests), and up to two more vehicles holding additional crew and equipment.
We cross the runways and taxiways of the Mojave Air and Space Port, past the “bone yard” of old aircraft, then into an area populated by numerous test sites for many of the space port tenants.
Because we travel within the boundaries of the airport and cross active taxiways and runways, we must have aviation radios and follow specific operational and communication procedures prior to departure, during movement, and upon leaving the active flight line. We pre-coordinate test activities with the local space port staff and first responders so they are fully aware of the planned activities and can, if they wish, monitor our activities in real time.
Tomorrow – What happens when we arrive at the test stand?
Brandon Litt (R) and Mike Valant (L) move the stand out from the XCOR hangar.
Welcome to a day in the life of a hot fire. This is a journey through the experience of a test day where we work on a new, experimental rocket engine.
Due to the fact that the rocket engine is currently being proven, we maintain a very high level of safety protocols during each test. Once we’ve proven to ourselves that the engine is “maturing” we perform tests with our team members in closer proximity. In the future we will perform rocket engine firings with people onboard Lynx. But right now, we are showing you those first early engine firings when you need to expect the unexpected.
On the morning of a hot fire, the hangar is abuzz with activity. Members of the test team start to arrive around 6:30AM and begin to check and double check equipment and procedures. The team reviews what they will do, and everyone prepares for the day.
At around 7AM, the Lynx truss is rolled out of the hangar, and fueled-up with liquid oxygen (LOX) and kerosene. In the meantime, the test truck and vehicle convoy are loaded with all of the support equipment needed – tools, data acquisition, control box, safety equipment — in short, everything required to complete a test.
There are checklists for everything, including equipment inventory, stand setup, pressurization, hot fire, and shutdown. These checklists add safety and take the guesswork out of operations, and are a standard item in the world of aerospace testing and operations.
Tomorrow, take a trip out to the test stand and spend an afternoon with us.
We’ve decided to mix it up this week and give you a “Day in the Life of a Hot Fire.” Over this entire week, we will show you how a hot fire happens through photos, videos and posts. Stay tuned this afternoon for more.
Lynx has a tail-less design that eliminates the weight and complexity of an additional set of airfoils, but it didn’t start out that way. The original design had canards! Now, a single set of double-delta wings with large vertical stabilizers at each end allow for a sleek, simplified airframe that makes the Lynx the sports car of spacecraft.
In the coming weeks, we’ll discuss how our subsonic wind tunnel test program has shaped the design of Lynx, and much more.
XCOR’s Jeff Greason and Dan Delong conduct slosh tests using water in an engineering model of a single strake fuel tank. These slosh tests help determine where baffles are needed in each tank to control the sloshing of Lynx fuel along the strake tank walls.
Above, center: Note the position of the fuel tanks, wing strakes, strake thrusters (RCS) and main landing gear in the Lynx cutaway.
In function, each strake contains four of Lynx’s kerosene fuel tanks, the main landing gear for each side of the aircraft, and two reaction control thrusters that are used to maneuver the vehicle when it is outside the Earth’s atmosphere.
In the coming weeks we’ll show you more background on Lynx wing strakes, including some really cool shots and more on their geometry and function.
The Lynx flight panel is designed around a two-screen electronic flight instrumentation system. This system gives our pilots all the flight path and performance they require on the left screen and, on the right, all the information necessary to manage the engine and Lynx systems. Other instruments surrounding the main screens are present as backups. It is hinged around a center post and swings out for easy maintenance.
More on cockpit origins and progress in the coming weeks.
Pictured is an illustration of the final product in action at about 100 kilometers.
The propulsion system on Lynx is supported by a steel truss that attaches to the rear firewall of the fuselage. Composite blast shields surround each engine.
In front of the engines, the truss supports all the valves, pumps, and plumbing needed to control and deliver fuel and oxidizer to the engines. In these shots, engineer Jeremy Voigt checks for small control line leaks using a stethoscope.
Future astronauts visit the Lynx model at the CAF AIRSHO in Midland, Texas.
Update via Terri Carroll of XCOR, currently in Midland, Texas:
“This weekend XCOR is busy at the CAF AIRSHO in Midland, giving tours of our full-scale Lynx model and discussing XCOR plans with attendees.
We spent Saturday introducing visitors to the company and escorting children through the Lynx cockpit. About half of our visitors were surprised to learn that their local airport would soon become a space port, and kids sitting in Lynx were thrilled to find out they could one day visit the space port to watch the vehicle take off to space–and perhaps even take a trip themselves.
Blurry but still awesome: The Shockwave Jet Truck powers down the runway at the airshow. Impressive! –Via Greg Claxton of XCOR
The most frequently asked question is “when will you be here?”
We are in fact already here! We’ve hired five Midlanders already–some of whom are at our AIRSHO booth this weekend, and our presence is increasing in the community (including today!)
Visitors also asked a number of questions about XCOR jobs. Stay tuned by following XCOR on Twitter and through our jobs page, where we will continue to list new postings over the coming months.