Following my previous blog on hypersonics, here I share my experiences of supporting flight trials, the opportunity to put our engineering to the test and see if it works.
I have been lucky to attend several flight trials since 2012 in extreme locations. Some were in the Arctic Circle at the Andoya Rocket Range, Norway. Others were in the desert at the Woomera Test Range in South Australia.
The excitement of the countdown is unforgettable. As the team performs final system checks, the point of no return fast approaches.
T minus two (2) minutes … Wind is GO
At T minus 1 minute the pace of the countdown procedure seems to accelerate.
“Rocket motor is armed” comes through the intercom. This is real.
T minus 30 seconds … “GPS is go, IMU is GO, TM is GO, payload is GO.”
“We are GO for launch. No external aborts” is the call through the intercom.
“Range is GO”
The atmosphere in the science room (mission control) is thick with anticipation, nervous excitement.
T minus 10, 9, 8 … 3 2 1 …
The bright flash of the first stage ignition is instantaneous and applauded – the guttural roar takes a few seconds to reach us; it resonates in our chests, but as soon as it does you can feel the immense energy. The rocket motors generate serious thrust, and our vehicle is quickly out of sight, leaving behind a trail of smoke and any chance to intervene on its journey. We are passengers now.
All eyes then focus on the live telemetry stream, hoping for a signal lock. Cheers erupt when data starts feeding in, projecting onto big screens graphs and signal values. It shows us things are ‘nominal’. Nominal is excellent in this context, extraordinary is a disaster!
Time goes very quickly while waiting for the flight to end. The second stage ignition must work, then de-spin, nosecone eject, payload separation, so many things must go right. Once separated the payload needs to perform its mission. Whilst thousands of simulated flights should reassure us, in practice we hold our breath, glued to the data feed, watching for anything unexpected; asking ourselves: “What is it doing?”, “Why is the gas pressure that low?”, “Is it working?”
For many experimental flights the answer has been a resounding and celebrated “yes!”
As the scientific lead for HIFiRE4, the anticipation is overwhelming when the payload does exactly as it should! Now the re-entry autopilot needs to work as predicted. Thousands of re-entry simulations again help to reassure us, but this thing is really flying now at 7,200km/hr back towards the earth.
As the atmosphere thickens during descent, the autopilot starts to function and we breathe a sigh of relief, but that’s just the start.
At a pre-programmed flight condition, the autopilot seamlessly assumes closed loop control and it holds the vehicle steady, just as it did in simulations. Everything is nominal. No, it’s even better than we expected!
It is surreal as I call out the critical events. The vehicle is well under control, the control surfaces are hardly moving, but we are falling fast into the extremes of hypersonic re-entry.
“All signals nominal” I call. However the hostile environment is building; heat, pressure, load, vibration, real flight… all build and build; we wait for something to fail. Peak loading comes and goes without incident.
“Peak dynamic pressure” I call, it has made it through that critical milestone…
“Primary experiment complete” I call triumphantly soon after.
Our anxiety subsides and boils into exuberant cheer. What an immense relief, all those years of work are vindicated. We feel emotion and great relief; I fight to stay composed, and fall silent.
“Keep calling it” urges the leader. The vehicle is still flying way beyond our expectations. I continue to commentate, but now relaxing and enjoying the moment, we cheer it on like we are at a sporting match. It was a real career highlight for me and the whole team.
This success proves Australia can overcome the challenges of high speed flight.
The nation can contribute to hypersonic vehicle development and flight testing on the global stage. Defence interest in high speed flight provides significant opportunities for industry in the near future. BAE Systems’ hard won credibility and demonstrated capability positions us to lead these endeavours.
Further research of hypersonic technologies is ongoing. Adjacent opportunities exist to leverage the technologies and capabilities for access to space, and to explore useful applications of high speed flight vehicles.