Why is Sierra Space’s Dream Chaser spacecraft not ready for flight?
In a press release posted last week Sierra Space proudly announced that its Tenacity Dream Chaser mini-shuttle has completed its pre-launch ground vibration tests at the Kennedy Space Center in Florida, but instead of moving the mini-shuttle to a local facility where it could be integrated with its rocket for launch, the company announced it was shipping it back “to Colorado for final modifications and mission-specific upgrades.”
Normally when a spacecraft, satellite, or any payload passes these last ground tests, it is ready for launch, and it immediately begins integration onto the rocket that will carry it into space. That Sierra Space is not doing this strongly suggests Tenacity did not pass with flying colors, and that some issues were identified that need correction.
Note too that this spacecraft had been delivered for these tests in early 2024, and had been expected to pass them then and be launched that year. Instead, months passed with no word, then its launch was postponed indefinitely, and then NASA canceled Sierra’s contract to provide cargo to ISS.
Now, two years later Tenacity is still not ready for launch. Though the company says the ground tests are now complete, I suspect otherwise. I suspect there is some fundamental issue with the spacecraft that they are hiding because to reveal it would be devastating to Sierra’s public reputation.
Until we know more however this is pure speculation on my part. What we do know however is that this mini-shuttle has not done what was promised, and increasingly appears to be a lemon that will never do it.
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
In a press release posted last week Sierra Space proudly announced that its Tenacity Dream Chaser mini-shuttle has completed its pre-launch ground vibration tests at the Kennedy Space Center in Florida, but instead of moving the mini-shuttle to a local facility where it could be integrated with its rocket for launch, the company announced it was shipping it back “to Colorado for final modifications and mission-specific upgrades.”
Normally when a spacecraft, satellite, or any payload passes these last ground tests, it is ready for launch, and it immediately begins integration onto the rocket that will carry it into space. That Sierra Space is not doing this strongly suggests Tenacity did not pass with flying colors, and that some issues were identified that need correction.
Note too that this spacecraft had been delivered for these tests in early 2024, and had been expected to pass them then and be launched that year. Instead, months passed with no word, then its launch was postponed indefinitely, and then NASA canceled Sierra’s contract to provide cargo to ISS.
Now, two years later Tenacity is still not ready for launch. Though the company says the ground tests are now complete, I suspect otherwise. I suspect there is some fundamental issue with the spacecraft that they are hiding because to reveal it would be devastating to Sierra’s public reputation.
Until we know more however this is pure speculation on my part. What we do know however is that this mini-shuttle has not done what was promised, and increasingly appears to be a lemon that will never do it.
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
I spoke with some Sierra Space folks at the Space Symposium this year. They’re focusing on customers other than NASA (i.e., DoD?), so I suspect that means they’re putting some other kind of payload on board, rather than cargo for the ISS.
Ballonman: Of course they aren’t putting ISS cargo on Tenacity. NASA canceled their contract in September 2025. Whether they have found any other customers remains unknown.
The real question is why this spacecraft still needs “final modifications?”