Falcon 9 aborts automatically at T minus 0
A SpaceX launch attempt today to put sixty more Starlink satellites into orbit aborted at T minus Zero when the rocket’s computer software shut things down just after the engines began firing.
I have embedded the video below the fold. According to the broadcast, they had “a condition regarding engine power,” suggesting that one or more of the Merlin engines did not power up as expected and the computers reacted to shut the launch down because of this.
Not surprisingly, they have not yet announced a new launch date.
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 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
A SpaceX launch attempt today to put sixty more Starlink satellites into orbit aborted at T minus Zero when the rocket’s computer software shut things down just after the engines began firing.
I have embedded the video below the fold. According to the broadcast, they had “a condition regarding engine power,” suggesting that one or more of the Merlin engines did not power up as expected and the computers reacted to shut the launch down because of this.
Not surprisingly, they have not yet announced a new launch date.
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 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
Most of the time I don’t like the notion of humans being ‘out of the loop’ for things like this. But given how fast the onboard computers shut things down, I do see the appeal of having such a quick response.
There’s pretty much no possibility of human in the loop for most of the T-0 conditions, things happen too quick, and holding the rocket on the mounts long enough for a human to evaluate things and make a decision is highly undesirable. One of my college compsci classes actually had a fascinating lecture series on the design of the controller logic of, if I recall correctly, one of the later Delta launchers. They had to go so far as to have decisions being made in the engine controller itself, because sending the raw data behind that decision the extra few meters to the main rocket controller imposed too much lag, and also required more bandwidth (and thus more heavy cable and interconnects) than they really wanted to route through that part of the rocket. I can only imagine how that scales to 9 not to mention 27, Merlin engines.
David–
Great factoids!
(Does that Lecture, exist anywhere?)
If I’m recalling correctly— light travels 1 foot in 1 nanosecond.
Electrical signals theoretically propagate at the speed of light but that depends heavily on the type of cable through which it’s running. (as you noted)
IIRC, when they built the first Cray supercomputer, propagation delay along the wires was a major consideration. One of the reasons why that computer was circular in shape was to reduce the length of the interconnecting wires.
Grace Hopper, the Navy officer who invented the COBOL programming language, used to hand out “nanoseconds” to her students. They were one foot lengths of wire.
“light travels 1 foot in 1 nanosecond.”
Spot on!
(300,000,000 m/sec) / (1,000,000,000 ns/sec) = 1/3 m = about a foot
Andi-
IIRC– for the Cray, no critical connections are more than 1 foot apart. (didn’t this come up ‘like a year ago for something else?)
Tangentially related– “Krytron,” an extremely fast switch used for early RADAR, and to trigger a symmetrical implosion detonation for nuclear weapons.
Diane–
I really enjoy your ‘inside-baseball’ tidbits!
They should have known not to try to launch on March 15th.
Beware the Ides of March.
Diane Wilson-
In later years, as computers got faster, a nanosecond was too slow. So Hopper started handing out packets of pepper. A flake of pepper represents the distance light travels in a picosecond: one trillionth of a second.
To a designer of modern integrated circuits, a nanosecond is a really, really long time. On the other hand, ten picoseconds, now that’s pretty speedy.