Visually and anecdotally, if I understood what I was seeing, while standing
at Port Canaveral (https://goo.gl/NqW5h5), the first stage boost was more
vertical than usual, MECO and staging was still nearly overhead, only
slightly out to sea (maybe 30 degrees off vertical, 100 km altitude, 60 km
downrange). I'm guessing someone here will jump in with better numbers.
I may be completely misunderstanding the flight profile, but following
MECO, there appeared to be a long wait (minutes) with the first stage in
free-fall, no visible light.
We then saw what looked like a boostback burn out there at about 45 degrees
-- I was struck by how short that burn appeared to be; a few seconds. (I
could have the sequencing wrong -- it makes sense to me that the boostback
should be before free-fall, not the other way around. But I remember it
after. Ben, did you note how that went?)
The boostback was followed by another long pause (a minute or so), and
another short burn straight overhead, I'm guessing to halt the uprange
velocity resulting from the boostback.
After that, we had a clear view up the tailpipes with the booster in
free-fall right over the Cape; I was struck by the fact that it looked like
they were keeping the fires lit at something like 10% throttle (I don't
know how deep the Merlins can actually go); just a flickering glow.
Finally, at only 30 degrees or so above the horizon, maybe 4 miles up, we
got throttle up, and a nice deceleration all the way to the pad -- looked
completely unreal. Hollywood.
After touchdown and the glow fading, there were a tense few seconds there,
some folks cheering and the rest of us waiting for a fireball... Right
then the sonic booms reached us, a rippling tear rather than a clear single
or double. I heard later that even Elon got tripped up by that -- the
timing of the shock waves was perfect for fooling the brain into thinking
Something Bad had happened. The cheers really started a few seconds later
when we got the video of the booster sitting solidly on its legs.
I'm still processing it. Beyond the rain, the humid Florida breeze,
standing there in the dark watching all this... The thing that most made
it surreal was the agility, the dynamic behavior of that vehicle. I grew
up in Florida and once lived near the Cape. Instead of the plodding,
predictable, near ballistic, conservative trajectory we've all been used to
with large vehicles, there was this huge heavy thing bouncing all over the
sky. Big rockets just don't act that way. ;-) Completely different
world.
Steve
On Tue, Dec 22, 2015 at 10:17 AM, John Dom <johndom@xxxxxxxxx> wrote:
http://www.parabolicarc.com/2015/12/21/spacex-falcon-9-orbcomm2-mission-overview/#more-57125
Table in text: does boostback burn mean sort of a translation burn to the
pad?
jd
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
*On Behalf Of *David McMillan
*Sent:* dinsdag 22 december 2015 18:42
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: SpaceX F9 Launch/Update -- Live Link
Well, like they say, the best way to get a correct answer on the
internet... :)
On 12/22/2015 12:27 PM, Lars Osborne wrote:
David,
I was told by one of my coworkers that the simulation you posted is old.
This one is supposed to be more accurate (and way more detailed):
http://www.flightclub.io/results.php?id=0490d68b-62a1-4a2a-b39a-f47bacadc6e3&code=OG22
Thanks,
Lars Osborne
On Tue, Dec 22, 2015 at 9:11 AM, David McMillan <skyefire@xxxxxxxxxxxx>
wrote:
On 12/22/2015 12:04 PM, John Dom wrote:
As to the successful F9 v1.01 stage 1 return yesterday, again I’d love to
see the 3D graph (km scale) of the booster *return* trajectory. The gravity
turn to orbit as shown on ascent footage must have sent it far down from
the pad. How high did it fly? Range at separation?
Not entirely sure of the provenance, but here's one (2D) I came across.