Third SLS dress rehearsal countdown scrubbed before completion
NASA engineers today scrubbed their third attempt to complete a dress rehearsal countdown of the agency’s giant SLS rocket when a leak was detected in a hydrogen fuel line.
The team will not conduct the terminal countdown activities today as planned and will assess next steps after today’s operations.
The problem appears to be “a leak … in the tail service mast umbilical.”
It is not clear yet how much of the countdown and fueling will be completed. Because of a faulty valve in the upper stage, NASA management had already decided to eliminate fueling of the rocket’s upper stage from the rehearsal. The problem today appears to involve the core first stage’s hydrogen tanks, which are presently partly filled only about 5%. Based on their last tweet, it appears they have not drained the tank, though they apparently will not continue the rehearsal today.
UPDATE: NASA just tweeted the following:
Teams have confirmed they have satisfied the test objectives for the ICPS [upper stage] LH2 [hydrogen tank] chilldown and after gathering additional data, will work to drain propellant from the rocket. They will inspect the TSMU umbilical connection, review data, and establish a go-forward plan.
This sounds as if the agency might decide they have completed enough of the dress rehearsal to consider it complete, and will now roll the rocket back to the vehicle assembly building for further check out.
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
NASA engineers today scrubbed their third attempt to complete a dress rehearsal countdown of the agency’s giant SLS rocket when a leak was detected in a hydrogen fuel line.
The team will not conduct the terminal countdown activities today as planned and will assess next steps after today’s operations.
The problem appears to be “a leak … in the tail service mast umbilical.”
It is not clear yet how much of the countdown and fueling will be completed. Because of a faulty valve in the upper stage, NASA management had already decided to eliminate fueling of the rocket’s upper stage from the rehearsal. The problem today appears to involve the core first stage’s hydrogen tanks, which are presently partly filled only about 5%. Based on their last tweet, it appears they have not drained the tank, though they apparently will not continue the rehearsal today.
UPDATE: NASA just tweeted the following:
Teams have confirmed they have satisfied the test objectives for the ICPS [upper stage] LH2 [hydrogen tank] chilldown and after gathering additional data, will work to drain propellant from the rocket. They will inspect the TSMU umbilical connection, review data, and establish a go-forward plan.
This sounds as if the agency might decide they have completed enough of the dress rehearsal to consider it complete, and will now roll the rocket back to the vehicle assembly building for further check out.
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
At the rate things are going, wouldn’t be surprised to see the rocket explode mid-maiden flight…
(Don’t wish for it, but wouldn’t be surprised. That is, if it’s ever launched at all!)
Close enough for Government work.
A cryo leak that manifests at cryo temperatures is a difficult problem. An LH2 leak is even worse due to the hazards. NASA is probably revisiting the events of the summer of 1990 when similar leaks appeared in multiple shuttles and Congress ended up grounding the fleet until the problem was solved. Few people know the root cause that was found. Anyone here know?