A Day in the Life of a Hot Fire, Part Five: Ignition!

We’re at countdown to ignition!

After the crew has run through the stand setup, controls, and pressurization checklists (and a little lunch) they settle into the day’s series of hotfire objectives. Sometimes it can be a duration goal, a certain number of successful tests in a row with a new part, a certain pressure setting, fuel / LOX ratio change, or any combination of test objectives to further the test program.

The countdown for a hot fire is really the rundown of a detailed checklist that has been customized to test objectives. A majority of the checklist is nearly identical to many other tests, but there may be slight differences depending on the objective. There are built-in holds for tasks such as chilling down the pumps or waiting for the system to pressurize.

Regardless, as the checklist nears the bottom, the tension in the bunker starts to rise. Is it all correct? Did we set it up right? Are there any leaks? Will the new design work properly? All of those questions and more run through the team.

Then it’s time … “Engine run in three, two, armed! …”


Check out this video to experience what it’s like to prep and execute a hot fire:

A successful test results in beautiful images and beautiful data. 

This image (the thumbnail shot in the video above) was taken remotely by XCOR photographer and video engineer Mike Massee. It shows a brilliant plume overpowering the bright noon desert sky.

When a test series is concluded, the stand is disconnected, the bunker test equipment broken down and everything  is packed for the return. Our convoy makes its way back to the XCOR hangar, and on a good test day where everything goes smoothly, the crew typically returns between 3 and 4:30 pm. On later days it’s between 9 and 10pm.

After each test, an “after-action” meeting is held while all the information is still fresh in everyone’s heads. Each person present at the test is encouraged to bring up any issue, no matter how minor. There are no “dumb comments”, and all comments major and minor are captured on a “squawk list”. Suggested test stand or procedural changes are assigned to be completed before the next test. Data review is scheduled for the next day after everyone has had a chance to process and review the data on their own. And based on the data review, goals are set for the next test series.

Thanks for joining us for the “day in the life of a hot fire” series. Let us know what you think of it by connecting with us on Twitter or Facebook, or by emailing me at bryan [at] xcor [dot] com.