In article ,
says...
I'm going to be digging for info about the attempted water "landing" of
the first stage of the Falcon used to launch Dragon last week. This is
how SpaceX will demonstrate that there is enough residual fuel in Falcon
to safely land following a successful launch.


Both NASA and the Russians were watching this launch. From
www.newspacejournal.com:

When the launch does take place?be it today, tomorrow, or
next week?it will be closely watched, and not just by
spectators at Cape Canaveral and the usual radars and other
tracking assets used for any launch. That?s because of
SpaceX?s efforts to attempt to recover the vehicle?s first
stage, testing maneuvers to slow down and ?land? the stage,
albeit over the open ocean and not on land.

?When they do those braking maneuvers to come back and land
on the surface of the ocean, those braking maneuvers will be
supersonic thruster firings, which will be very similar to
what we?ll have to do for braking for a large mass going
into Mars,? said Bill Gerstenmaier, NASA associate
administrator for human exploration and operations, in a
presentation to a committee of the NASA Advisory Council on
Monday, before that afternoon?s SpaceX launch attempt was
scrubbed.

He said NASA?s Langley Research Center would be flying three
aircraft to observe those maneuvers, collecting data to
incorporate into their Mars technology developments. ?So
we?re actually getting data tonight to help us inform and
get us ready for the entry, descent, and landing challenge
of going to Mars,? he said. It wasn?t clear if the aircraft
would also be on station for the launch today, given the
weather conditions.

While NASA watches from the air, the Russians may be
watching from the sea. The Russian vessel Nikolay Chiker has
been lurking in the waters off the coast from Cape Canaveral,
the blog The Aviationist reported Thursday, appearing in
March for earlier launch attempts and returning in time for
the latest attempts. Some speculate the ship is there to
monitor the Falcon 9 launch and stage recovery attempt,
although it could be coincidental with other efforts, such
as monitoring naval bases.

Also, Elon tweeted the following on Apr 18:

"Data upload from tracking plane shows landing in Atlantic
was good! Several boats enroute through heavy seas."

"Data upload from tracking plane shows landing in Atlantic
was good! Several boats enroute through heavy seas."

No word yet on whether or not the stage was found by the boats or if the
boats would drag the stage back for inspection.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer