A rocket exploded during a test flight at the SpaceX Rocket Development and Test Facility in McGregor, Texas. An anomaly crept during the flight, triggering the rocket to self-detonate. No injuries are reported, and rumours are rampant.

While an unintentionally explosive test flight is a shocking thing to our risk-adverse society, it's actually an indicator of a healthy testing program. If we never push against the edges of what works and what we understand, we never learn something new. While details are scarce about what happened (and will be until SpaceX has time for a proper investigation), whatever it was it's a good thing to learn about in a controlled situation instead of accidentally during a commercial load with payloads (or, worse yet, people) at risk.

A SpaceX Rocket Test Just Went Explosively Awry

Explosion and smoking debris over the SpaceX test facility in McGregor, Texas. Image credit: Amanda Spence

While SpaceX's manufacturing arm is elsewhere, every new engine goes through testing at McGregor, along with all prototypes being developed for future missions. SpaceX can be fairly quiet about the details of what they're testing, both to keep proprietary secrets and to avoid running afoul of federal law prohibiting assisting foreign weapon development. So far, we know the specific craft being tested was a new prototype under development to replace the Grasshopper, a three-engine version of the Falcon 9 Reusable.

The McGregor facility was upgraded in 2012 when SpaceX bought surrounding farmland and constructed a concrete pad to run tests for the Grasshopper reusable rocket program.

A SpaceX Rocket Test Just Went Explosively Awry

A Grasshopper behaving normally during a test flight on 7 October 2013. Image credit: SpaceX

By October 2012, at least one engine test was happening every day, with the pace expected to keep increasing. In the spring of 2013, the facility also became the testing grounds for the loud, powerful Merlin 1D engines, the first-stage engine for the Falcon 9 rocket. Even the beloved Dragon, the reusable spacecraft, makes its way through the facility frequently. After each mission to the space station, the capsule is sent to McGregor to reclaim any excess fuel, clean it up, and do any refurbishment necessary to get it ready to be used again in another mission.

SpaceX released the following statement about the incident:

Earlier today, in McGregor, Texas, SpaceX conducted a test flight of a three engine version of the F9R test vehicle (successor to Grasshopper). During the flight, an anomaly was detected in the vehicle and the flight termination system automatically terminated the mission.

Throughout the test and subsequent flight termination, the vehicle remained in the designated flight area. There were no injuries or near injuries. An FAA representative was present at all times.

With research and development projects, detecting vehicle anomalies during the testing is the purpose of the program. Today's test was particularly complex, pushing the limits of the vehicle further than any previous test. As is our practice, the company will be reviewing the flight record details to learn more about the performance of the vehicle prior to our next test.

SpaceX will provide another update when the flight data has been fully analyzed.

Controlled detonation is a common practice as a response to certain problems, particularly in situations where people may be at risk. Whatever SpaceX tests at McGregor is bound to have a Flight Termination System, or FTS, installed for remote detonation of the test vehicle if things go awry. From videos of the ill-fated flight, it looks like the rocket starts to get a bit squirrely, tilting over just before the the detonation is initiated.

For now, we don't know what anomaly triggered the detonation. We won't know unless SpaceX releases a post-mortem after the investigation, but in the meantime we can all speculate wildly. It could be anything from engine malfunctioning to control system divergence, or something far more obscure. As today's tests are described as "complex" and "pushing the limits," it could have been extreme diversion or recovery maneuvering that triggered a glitch.

A SpaceX Rocket Test Just Went Explosively Awry

The mishap was well-documented by the residents of McGregor, with photographs and videos getting posted to Twitter, Instagram, YouTube, and the NASA Spaceflight Forum. No injuries are being reported, including of the iconically unimpressed Rocket Cows. Some residents are commenting that they could feel their houses shake.

Smoking debris. Image credit: spkinch

The Falcon 9 rockets are theoretically able to handle up to two RUDs (that's the coy spaceflight acronym "rapid unscheduled disassembly") and keep on functioning. It's even been unintentionally tested before, when pieces fell off the rocket during a test flight in October 2012. The incident resulted in one of my favourite soundbites about rocket testing, with Elon Musk telling BBC:

On the plus side, we demonstrated that we can indeed complete a mission if we lose an engine, including in a relatively violent way.

People are also posting videos of the smoking wreckage and grass fires:

The local news station, KWTX, is collecting more videos of the incident.

A SpaceX Falcon 9 rocket is scheduled to launch on Tuesday from Cape Canaveral, carrying an AsiaSat 6 satellite into orbit. So far, there's no word on the incident delaying or cancelling that launch, and the static firing in preparation for the launch went ahead as scheduled.

Occasional setbacks are part of rocket science. Although never welcome, a test flight going badly awry is indication that SpaceX is pushing the boundaries of what we know while developing the next generation of reusable rockets. NASA Spaceflight forum contributor e of pi points out that during a 2013 TED talk, President of SpaceX Gwynne Shotwell lamented:

"So we're 5-for-5 testing on this Grasshopper. But, but that means we're not pushing hard enough. We've got to tunnel one of those vehicle into the ground by trying something really hard. We haven't done that yet. So now our challenge to our test team is you've got to push hard enough that we're going to see something happen. A spectacular video."

This matches exactly with what NASA Administrator Charles Bolden expressed while speaking to NASA Social during the Orbital Carbon Observatory launch: part of spaceflight is pushing the limits, testing things in the realm we don't yet know and understand. If everything goes well every time, that's because we're not hitting the limits yet, and need to venture further into the unknown. We're understandably risk-averse in our space program, but we can't be in our testing program if we don't want to stagnate.

Although visually spectacular, the mishap injured no one, didn't destroy a commercial payload, and will hopefully teach SpaceX's engineers something new about their rockets. Rocket science isn't easy, and failure is part of the process.

Here's to hoping the hexacopter survived the blast, and SpaceX will have some astonishing footage of the explosion from the drone in the next few days.

Is your lust for fiery spacecraft deaths not yet sated? The space station released a high-definition timelapse of the Cygnus rocket's destructive reentry!