It really is rocket science

[RoadKingLarry]

Anybody else geeked out about the Blue Origin rocket test?
 
https://www.youtube.com/watch?v=9pillaOxGCo

[mgdavis]

Pretty amazing feat. I watched the video clip twice.

[cornerrow]

Amazing idea... Surely this is a new beginning in rocket and space expedition and safety plus this could also be a good tourism business.

[RocketMan]

Pretty slick.  It was interesting how the rocket passed through 12k feet still falling like a rock before the engine started.  The rapid deceleration so close to the end was impressive.
I've read some comments that said they did a quick restart of the engine and briefly bounced the rocket a few feet back up and then landed it again.  I've not seen that in any of the videos, however.

[seeker_two]

Now all those 1950's sci-fi movies are going to look a lot more realistic.....

[AJ Dual]

Now all those 1950's sci-fi movies are going to look a lot more realistic.....

Kind of apples to oranges... but what they're doing, which will give 4 minutes of ballistic coasting in free-fall on a (very) suborbital trajectory, vs. SpaceX...

[230RN]

Exquisite control.  Impressed.  

Armadillo rocketry Aerospace, September 2010.  Baby steps:

https://www.youtube.com/watch?feature=player_embedded&v=k_Xiq3dYJlM

I think they were using oxidizer sprayed into a solid-fuel engine for thrust control.

Terry, 230RN

Highly sophisticated test site entry warning:

[AJ Dual]

Exquisite control.  Impressed. 

I thought the control oscillations were terrifyingly large, unless they were intentionally showing off.  From a safety or design standpoint, there's zero reason it needed to be swinging that far. Kudos to the control system for keeping it upright and landing where they wanted it, but I get the feeling they came within a gnats-ass of crashing.

How far it fell ballistic, and how close to the ground it got before the rocket started braking for the hover and landing also makes me suspect they have a very narrow fuel window, possibly because it had to be that low to make weight, but also cuts into your hover/landing time drastically.

Although I concede that Birdman could pop in here and tell me why I'm wrong in five seconds flat. 

[230RN]

Maybe they were trying for the X-ring.  

I wonder if the ground-sensing radar was picking up signals from the ionized gases on the landing pad instead of the landing pad itself, causing that error.

But I guess your "exquisite" and my "exquisite" differ.  After all, it did not fall over.

Note the bouncing on the landing legs of the Armadillo rocket flight I posted.  "Whoopsie... Ah! Gotcha."

Terry

[birdman]

I thought the control oscillations were terrifyingly large, unless they were intentionally showing off.  From a safety or design standpoint, there's zero reason it needed to be swinging that far. Kudos to the control system for keeping it upright and landing where they wanted it, but I get the feeling they came within a gnats-ass of crashing.

How far it fell ballistic, and how close to the ground it got before the rocket started braking for the hover and landing also makes me suspect they have a very narrow fuel window, possibly because it had to be that low to make weight, but also cuts into your hover/landing time drastically.

Although I concede that Birdman could pop in here and tell me why I'm wrong in five seconds flat. 

Nope, not wrong.
Also, they can get away with it more than spaceX as their rocket is basically an order of magnitude smaller (the whole thing is about as big as an F9 LEG!), so it's terminal velocity is way slower, thus doesn't need as much impulse to stop it).

However, lower length/diameter means harder to balance (think 12" ruler on your hand vs yardstick) and lower lever-arm for the off axis thrust = larger deflections required.  Also, single engine vs 9 that all have variable throttle.

The -only- thing they did that wasn't done before is (pardon the Boolean)
((Return from suborbital >20,000ft) ANDNOT (with substantial excess velocity) AND (land successfully) AND (on land) AND (on surface level with surrounding)

However, that's really not that amazing.  Both DCX (roughly the same size) and grasshopper (way bigger) did all of the above, just at much lower altitude, and F9 did all but successfully land MULTIPLE times, in a much harder environment, AS PART OF a mission that had nothing to do with landing.  SpaceX is -only- doing the landing as a "why not, it's cheap testing on something we are already doing, where we -really- don't care if the landing works, and it doesn't impact the primary mission).

Hell, the only reason grasshopper couldn't do the same altitude as BO is they really didn't care to.

[Regolith]

However, that's really not that amazing.  Both DCX (roughly the same size) and grasshopper (way bigger) did all of the above, just at much lower altitude, and F9 did all but successfully land MULTIPLE times, in a much harder environment, AS PART OF a mission that had nothing to do with landing.  SpaceX is -only- doing the landing as a "why not, it's cheap testing on something we are already doing, where we -really- don't care if the landing works, and it doesn't impact the primary mission).

Hell, the only reason grasshopper couldn't do the same altitude as BO is they really didn't care to.

Yeah, when they do it with something that was designed to help boost a payload into orbit, then I'll be impressed...

[230RN]

....
I wonder if the ground-sensing radar was picking up [false] signals from the ionized gases on the landing pad instead of the landing pad itself, causing that error.

I'm surprised nobody picked up on this.  Is it possible?

Seems to me that they'd need a "vertical-sensing" method which was independent of the gyros on board to verify distance and orientation to the ground on landing.  This might be by radar, ultrasonic, or infrared sensors.

It strikes me that any of those methods could be screwed up by the hot gases splattering out from the landing pad.  However, my question was with respect to radar-sensing.  Could the hot ionized exhaust gases give a false return signal, thus giving that sudden tilting?

Terry

[Fly320s]

For a run of the mill, airliner-type radar altimeter, I would guess that the gases would mess up the sensing.

I would hope that these rocket scientists would use something a little more better than an off the shelf part.

[Scout26]

I thought the control oscillations were terrifyingly large, unless they were intentionally showing off.  From a safety or design standpoint, there's zero reason it needed to be swinging that far. Kudos to the control system for keeping it upright and landing where they wanted it, but I get the feeling they came within a gnats-ass of crashing.

How far it fell ballistic, and how close to the ground it got before the rocket started braking for the hover and landing also makes me suspect they have a very narrow fuel window, possibly because it had to be that low to make weight, but also cuts into your hover/landing time drastically.

Although I concede that Birdman could pop in here and tell me why I'm wrong in five seconds flat. 

But that's just the reusable booster, the payload capsule lands separately via parachute

[AJ Dual]

But that's just the reusable booster, the payload capsule lands separately via parachute

Yah, I  understand that.

But if it's landing that wildly every time,  it's not going to be that "reusable" for long.

To my inexpert eye,  it looked barely under control.  And the resident rocket scientist did not say I was wrong.

[birdman]

I'm surprised nobody picked up on this.  Is it possible?

Seems to me that they'd need a "vertical-sensing" method which was independent of the gyros on board to verify distance and orientation to the ground on landing.  This might be by radar, ultrasonic, or infrared sensors.

It strikes me that any of those methods could be screwed up by the hot gases splattering out from the landing pad.  However, my question was with respect to radar-sensing.  Could the hot ionized exhaust gases give a false return signal, thus giving that sudden tilting?

Terry

Gasses aren't hot enough to cause that interference.  .

[Fly320s]

Gasses aren't hot enough to cause that interference.  .

But are they dense enough?

We get RA problems with snow and ice on the runway and with deice fluid on the antenna.

[cornerrow]

Question is how does it cost per launch and drop cost?