DavidMcCann
Well-Known Member
- Joined
- May 15, 2016
- Messages
- 2,656
- Reaction score
- 180
[youtube]KPEKrixDaL0[/youtube]
Dude....did that thing do a 360 under thrust?
Dude....did that thing do a 360 under thrust?
OK who RSO'd that one? (New Shepard)
- Thread starter DavidMcCann
- Start date
Help Support The Rocketry Forum:
- Joined
- Jul 15, 2015
- Messages
- 3,952
- Reaction score
- 2,696
That was CRAZY!
jrkennedy2
Well-Known Member
I think I feel motion-sick... 
H_Rocket
Death by Powerpoint
I love the deployment bags at 1:44
I would have given bonus points had they landed the capsule on top of the booster.
I would have given bonus points had they landed the capsule on top of the booster.
DavidMcCann
Well-Known Member
- Joined
- May 15, 2016
- Messages
- 2,656
- Reaction score
- 180
I think I feel motion-sick...
I think I'd rather ride out any 'flight anomaly' than pull that escape handle....
michigander
Well-Known Member
- Joined
- Jul 29, 2012
- Messages
- 1,821
- Reaction score
- 1
trouser chili flight
I love all these tests that Blue Origin are doing! They've definitely got a handle on the basics of landing a booster. When they get as far along as SpaceX is they'll be doing some incredible things! I can't wait.
Blue Origin has re-used the booster 5 times. Space-X has yet to re-use the Falcon-9 once. (Yes, we know that the Falcon-9 goes higher and faster.)
- Joined
- Jan 11, 2013
- Messages
- 6,450
- Reaction score
- 957
Holey crap...
And they just couldn't be happier..
They said is was an exciting flight for the crew that would have been aboard..
The crew would be desperately trying to get their colon back in their ass where it was before the loopdie loop....
Now you're freakin tellin me they can get the booster that is inherently unstable to land upright
and stick the landing like butter,,
but they can't between the lot of them figure out that they may need fins on that egg of a crew capsule....
OK,,
That wasn't like me,,
I feel better now,,
I'm sorry,,
Teddy
And they just couldn't be happier..
They said is was an exciting flight for the crew that would have been aboard..
The crew would be desperately trying to get their colon back in their ass where it was before the loopdie loop....
Now you're freakin tellin me they can get the booster that is inherently unstable to land upright
and stick the landing like butter,,
but they can't between the lot of them figure out that they may need fins on that egg of a crew capsule....
OK,,
That wasn't like me,,
I feel better now,,
I'm sorry,,
Teddy
Marginal stability issue on the prototype? Was much more stable (looked rock solid!) when it was under thrust and the exhaust plume was adding to the aerodynamic stability. Trouble seemed to creep in when the escape motor burnt (fizzled) out, perhaps changing airflow around and upsetting the craft.
Good data whatever happened. So it was a good flight for Blue Origin!
Good data whatever happened. So it was a good flight for Blue Origin!
- Joined
- Jan 11, 2013
- Messages
- 6,450
- Reaction score
- 957
It was a WONDERFUL flight...
Fantastic data..
I LOVE this kind of thing..
This is where we ( all man ) belong spending our money,,
not bickering like children over whose religion is better..
But boy,,
when I saw that flight and saw the instability right after separation,, no probs..
But then when the 2 announcers said nothing about it,, it was a great flight..
And then that there will be men in that capsule....
I was laughing so hard I couldn't breath....
The first time I saw Space X land a booster in that manner
and stick the landing perfectly I thought it was a hoax....
Truly beautiful flight...
Teddy
Fantastic data..
I LOVE this kind of thing..
This is where we ( all man ) belong spending our money,,
not bickering like children over whose religion is better..
But boy,,
when I saw that flight and saw the instability right after separation,, no probs..
But then when the 2 announcers said nothing about it,, it was a great flight..
And then that there will be men in that capsule....
I was laughing so hard I couldn't breath....
The first time I saw Space X land a booster in that manner
and stick the landing perfectly I thought it was a hoax....
Truly beautiful flight...
Teddy
- Joined
- Jan 17, 2009
- Messages
- 5,204
- Reaction score
- 1,547
SpaceX flew "Grasshopper" at McGregor 8 times, that's 7 re-uses.
And also flew Falcon F9-R five times at McGregor, 4 re-uses (Same # of re-uses as Blue Origin's, years earlier, with a booster designed for orbital launches albeit with only three engines mounted in it for those test flights).
Falcon-9 launches payloads into orbit. Massively huge difference between barely into "Space" vertical hops and launching tens of thousands of pounds of payload into orbit and doing a really "hot" re-entry from twice as high and IIRC abut twice as fast. Plus for payloads that do not weigh as much, like CRS missions sending Dragon spacecraft to resupply ISS, there is enough fuel left to stop the downrange momentum and fly back to land near the launch site.
New Shepard never has never flown anything but a straight up-straight down flight path, in other words never tilted over to thrust horizontally.
Having said that, it was impressive to see the successful abort, and that the booster did not get destroyed in the process as they 80-90% expected it to do. Some of the Apollo abort tests included a lot of end-over-end tumbling after burnout that would have been survivable but a hell of an ordeal for the crew to experience (pulling significant negative G's, and lateral G's, and positive G's during the tumbling at very high air velocities until the capsule finally stabilized heat-shield first into the airflow).
Last edited:
Salvage-1
Certified
- Joined
- Mar 17, 2012
- Messages
- 2,688
- Reaction score
- 41
I don't think it was a stability issue.
There were a set of specific maneuvres there, a right kick, back to norm, left kick, back to norm, 180, back to norm, then flipped over again for correct orientation for heat shield/parachute.
I am thinking RCS test.
There were a set of specific maneuvres there, a right kick, back to norm, left kick, back to norm, 180, back to norm, then flipped over again for correct orientation for heat shield/parachute.
I am thinking RCS test.
- Joined
- Jan 11, 2013
- Messages
- 6,450
- Reaction score
- 957
If that was all a maneuver test
that was even more impressive. ...
Teddy
that was even more impressive. ...
Teddy
You might just be onto something there. Makes sense.
- Joined
- Jan 17, 2009
- Messages
- 5,204
- Reaction score
- 1,547
The Shepard’s capsule seemed to be purely ballistic. Though I suspect there is a little bit of intentional misalignment of the thrustline and CG to help make it veer off a bit to one side when it fires, to make sure the capsule got away some distance horizontally from the booster. Apollo did this by using a separate small rocket motor near the top, firing horizontally to pitch it over a few degrees. Mercury did it by simply having the escape motor thrust slightly misaligned to cause a bit off-axis thrust line.
Anyway, it is had to tell when the Shepard’s Capsule abort motor actually burned out versus simply having some “afterburn”.
OK, I did some checking around. The escape motor burns for 1.8 to 2 seconds. The abort motor DOES have thrust vector control but it only works during that short thrusting phase. The wobble and tumble were well after it stopped thrusting. If it also was trying to use capsule RCS thrusters, they didn’t hold it. There’s no sense in purposely having 90 degree yaw to one side, and 90 to the other, and then a tumble-flip that seemed random for neutral stability. So if they were trying to use RCS as well to keep it oriented, they need to work in that.
Here’s a NASA Apollo Status Report Number 2, 1966. It has a lot of neat things such as Service module engine static testing, and RCS thrusters being tested. Also, three Apollo abort tests, Little Joe Mission A-003, A-004, and Pad Abort PA-2, beginning at a bit past 7 minutes into the video. Most relevant to this thread, is A-004 which did a pitch-up maneuver then fired the escape system. The front end of the Escape rocket had deployable canards that helped to flip the capsule around to make it point heat-shield first into the airflow. But it tumbled around a few times, FAST. Survivable, just not a fun ride.
[video=youtube;pvW03OYJ_1E]https://www.youtube.com/watch?v=pvW03OYJ_1E[/video]
Also note in the Pad Abort test (8:30 mark of the video) where that pitch motor I referred to fires at launch to push it from vertical towards a diagonal path. You can also see the nose canards deploy and start to flip the capsule before the LES separates.
In the A-003 Joe flight (before the 8 minute point) that broke up, the pitch motor was unable to make it pitch away because the vehicle was rolling so fast (this roll also prevented the canard system from flipping the CM around, but fortunately the drogues eventually pointed it the right way).
A-004 flight begins at 9:05. At about 9:34, the Joe is pitching up when the abort system fires. The capsule and LES tumble several times end over end at high speed. That was a somewhat worst-case abort as far as introducing multiple tumbles and high G-loads in various directions as it tumbled at very high speed and the air decelerated it.
Of course, lots of other neat stuff in that video, but the three Apollo aborts are somewhat relevant to this thread. Especially that fast tumbling on A-004
Anyway, it is had to tell when the Shepard’s Capsule abort motor actually burned out versus simply having some “afterburn”.
OK, I did some checking around. The escape motor burns for 1.8 to 2 seconds. The abort motor DOES have thrust vector control but it only works during that short thrusting phase. The wobble and tumble were well after it stopped thrusting. If it also was trying to use capsule RCS thrusters, they didn’t hold it. There’s no sense in purposely having 90 degree yaw to one side, and 90 to the other, and then a tumble-flip that seemed random for neutral stability. So if they were trying to use RCS as well to keep it oriented, they need to work in that.
Here’s a NASA Apollo Status Report Number 2, 1966. It has a lot of neat things such as Service module engine static testing, and RCS thrusters being tested. Also, three Apollo abort tests, Little Joe Mission A-003, A-004, and Pad Abort PA-2, beginning at a bit past 7 minutes into the video. Most relevant to this thread, is A-004 which did a pitch-up maneuver then fired the escape system. The front end of the Escape rocket had deployable canards that helped to flip the capsule around to make it point heat-shield first into the airflow. But it tumbled around a few times, FAST. Survivable, just not a fun ride.
[video=youtube;pvW03OYJ_1E]https://www.youtube.com/watch?v=pvW03OYJ_1E[/video]
Also note in the Pad Abort test (8:30 mark of the video) where that pitch motor I referred to fires at launch to push it from vertical towards a diagonal path. You can also see the nose canards deploy and start to flip the capsule before the LES separates.
In the A-003 Joe flight (before the 8 minute point) that broke up, the pitch motor was unable to make it pitch away because the vehicle was rolling so fast (this roll also prevented the canard system from flipping the CM around, but fortunately the drogues eventually pointed it the right way).
A-004 flight begins at 9:05. At about 9:34, the Joe is pitching up when the abort system fires. The capsule and LES tumble several times end over end at high speed. That was a somewhat worst-case abort as far as introducing multiple tumbles and high G-loads in various directions as it tumbled at very high speed and the air decelerated it.
Of course, lots of other neat stuff in that video, but the three Apollo aborts are somewhat relevant to this thread. Especially that fast tumbling on A-004
boatgeek
Well-Known Member
- Joined
- Dec 27, 2014
- Messages
- 7,382
- Reaction score
- 7,899
Could low/negative stability be a feature and not a bug? It seems that after you've burned out the motor and are about far enough away from the fireball (because that's the only reason to deploy this thing with people inside) that you're reasonably out of harm's way, you might want to slow down fairly quickly. Say for example the rocket was significantly off vertical when the escape system fires. You'd probably want to limit horizontal travel as much as you could, so some tumbling might not be so bad.
The scale of the tumbling didn't look awful either, not much worse than you see at the state fair. Of course, those are the rides that turn my stomach just to watch, so... Anyway, much like ejection seats, motion sickness no matter how bad is better than the alternative.
The scale of the tumbling didn't look awful either, not much worse than you see at the state fair. Of course, those are the rides that turn my stomach just to watch, so...
Anyway, much like ejection seats, motion sickness no matter how bad is better than the alternative.
Just had a discussion with an aeronautical engineer here. I think he nailed it.
It flies straight (nose first) under boost because that is how it is designed! At burnout the capsule would want to turn its base into the wind. That is how capsules are designed to fly. Maybe the afterburn was upsetting the aerodynamics a little, causing the attitude to flop about more than they would have expected. As speed decreases the desire for the capsule to point wide end into the breeze becomes greatly reduced or insignificant. As the craft picks up speed it stabilises and faces flat end into the breeze as we expect for capsules.
So probably a largely nominal flight, maybe with a bit of unexpected afterburn? Opinions?
It flies straight (nose first) under boost because that is how it is designed! At burnout the capsule would want to turn its base into the wind. That is how capsules are designed to fly. Maybe the afterburn was upsetting the aerodynamics a little, causing the attitude to flop about more than they would have expected. As speed decreases the desire for the capsule to point wide end into the breeze becomes greatly reduced or insignificant. As the craft picks up speed it stabilises and faces flat end into the breeze as we expect for capsules.
So probably a largely nominal flight, maybe with a bit of unexpected afterburn? Opinions?
Similar threads
