The last in the long family of Delta rockets is set for launch today from the Cape. Liftoff is 1:40 pm Eastern. For more details and to watch -
LINK On a personal note, Deltas were my favorite rocket, both to watch and to narrate for launch. The Delta II and III models were not only very reliable but just plain beautiful.
Rocky,
Thank you for posting this. Several questions - what is "maximum dynamic pressure" at 1:20 into flight? And the "payload fairing jettison" at 6:37, what happens with those pieces? By now it is orbit / space. Wouldn't those parts stay up there as junk and get in the way?
MaxQ is the point when aerodynamic forces peak. You can't tell by looking from the ground, but rockets don't fly exactly "point on". After they pitch over shortly after liftoff, they have to fly just a bit nose up to keep from falling over too fast. Flying just a wee bit "crooked" like that introduces bending in the rocket, which gets stronger as speed increases, but also weaker as the air gets less dense. At some point, those lines cross, and the bending forces get weaker despite the velocity going up rapidly. That point is called Max Q.
The fairings do get jettisoned in space - meaning above the atmosphere - but at much less than orbital speed. So, just like a bullet or arrow, they come down waaay downrange. Everybody except SpaceX wastes them. SpaceX has figured out how to have them re-enter and then pop parachutes to be recovered and used again. Since the fairings can cost from six to $10 million, that's pretty smart.
If you're old enough, you might remember the early days of rockets, when a lot of failures happened with the rocket just breaking up at a minute or so in flight. It wasn't just coincidence. That was how they learned about "maximum dynamic pressure."
MaxQ is the point when aerodynamic forces peak. You can't tell by looking from the ground, but rockets don't fly exactly "point on". After they pitch over shortly after liftoff, they have to fly just a bit nose up to keep from falling over too fast. Flying just a wee bit "crooked" like that introduces bending in the rocket, which gets stronger as speed increases, but also weaker as the air gets less dense. At some point, those lines cross, and the bending forces get weaker despite the velocity going up rapidly. That point is called Max Q.
The fairings do get jettisoned in space - meaning above the atmosphere - but at much less than orbital speed. So, just like a bullet or arrow, they come down waaay downrange. Everybody except SpaceX wastes them. SpaceX has figured out how to have them re-enter and then pop parachutes to be recovered and used again. Since the fairings can cost from six to $10 million, that's pretty smart.
If you're old enough, you might remember the early days of rockets, when a lot of failures happened with the rocket just breaking up at a minute or so in flight. It wasn't just coincidence. That was how they learned about "maximum dynamic pressure."
Great answer. Thank you Rocky.
kwg
Looks like they've update the liftoff time to 2:45 Eastern.
Sitting at the Cape live. It’s windy and overcast. Guessing it’s going to get delayed again.
Winds are problematic, but they're GO.
Well hell scrubbed for the day.
HOLD. Stand by...
Scrub for today 24-hr turnaround.
New Date/Time TBD as they troubleshoot the issue.
