Dragonfly’s rotors complete testing
According to a press release yesterday from the Applied Physics Lab (APL) in Maryland that is building the Dragonfly helicopter that is going to Saturn’s moon Titan, the rotors have completed the first round of testing, and are now about to undergo “fatigue and cryogenic trials under simulated Titan conditions.”
Over five weeks, from August into September, the team evaluated the performance of Dragonfly’s rotor system — which provides the lift for the lander to fly and enables it to maneuver — in Titan-like conditions, looking at aeromechanical performance factors such as stress on the rotor arms, and effects of vibration on the rotor blades and lander body. In late December, the team also wrapped up a set of aerodynamics tests on smaller-scale Dragonfly rotor models in the TDT [Transonic Dynamics Tunnel].
This quote about the manufacture of the rotors however stood out the most:
Pennington and team cut Dragonfly’s first rotors on Nov. 1, 2024. They refined the process as they went: starting with waterjet paring of 1,000-pound aluminum blocks, followed by rough machining, cover fitting, vent-hole drilling, and hole-threading. After an inspection, the parts were cleaned, sent out for welding, and returned for final finishing.
“We didn’t have time or materials to make test parts or extras, so every cut had to be right the first time,” Pennington said, adding that the team also had to find special tools and equipment to accommodate some material changes and design tweaks. [emphasis mine]
In other words, this is another hardware-poor NASA project. What they build is what they have. No time or money for testing of prototypes.
This mission is really pushing the envelope, possibly more than any NASA planetary probe in a half century. I just hope they get it right.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
According to a press release yesterday from the Applied Physics Lab (APL) in Maryland that is building the Dragonfly helicopter that is going to Saturn’s moon Titan, the rotors have completed the first round of testing, and are now about to undergo “fatigue and cryogenic trials under simulated Titan conditions.”
Over five weeks, from August into September, the team evaluated the performance of Dragonfly’s rotor system — which provides the lift for the lander to fly and enables it to maneuver — in Titan-like conditions, looking at aeromechanical performance factors such as stress on the rotor arms, and effects of vibration on the rotor blades and lander body. In late December, the team also wrapped up a set of aerodynamics tests on smaller-scale Dragonfly rotor models in the TDT [Transonic Dynamics Tunnel].
This quote about the manufacture of the rotors however stood out the most:
Pennington and team cut Dragonfly’s first rotors on Nov. 1, 2024. They refined the process as they went: starting with waterjet paring of 1,000-pound aluminum blocks, followed by rough machining, cover fitting, vent-hole drilling, and hole-threading. After an inspection, the parts were cleaned, sent out for welding, and returned for final finishing.
“We didn’t have time or materials to make test parts or extras, so every cut had to be right the first time,” Pennington said, adding that the team also had to find special tools and equipment to accommodate some material changes and design tweaks. [emphasis mine]
In other words, this is another hardware-poor NASA project. What they build is what they have. No time or money for testing of prototypes.
This mission is really pushing the envelope, possibly more than any NASA planetary probe in a half century. I just hope they get it right.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
“We didn’t have time or materials to make test parts or extras, so every cut had to be right the first time,”
Are you [word-of-choice] kidding me?! When I build something the first time, I *expect* to make errors. It is also significantly cheaper to ruin a few test articles before moving on to production. I am curious about the water jet, though; was the first cut, in fact, the deepest?
This thing is going to Titan but they cant build a replacement one for more Mars exploring.
The Dragonfly engineers and techs at APL are smart, dedicated guys who I think should deliver quality work product. But it is sobering to realize they’re running into these resource limitations on a mission whose cost has already exploded to flagship levels (now $3.35 billion!).
That isn’t entirely the fault of the Dragonfly team or APL. But it’s a reminder of how vulnerable to cost and schedule issues the NASA science bureaucracy is.