Falcon 9 first stage found, but probably not recoverable
spaceflightinsider.com
spaceflightinsider.com
Does anyone know if the first stage's landing legs were successfully deployed before the water landing? These are the 4 carbon fiber and aluminum legs (each 25ft / 7.6m long) that would be used to land the stage. I know that Falcon 9 launched with them, but I don't know if they were deployed. My suspicion is that they would have attempted to deploy them as well, for verification and validation purposes.
Here's a link which talks about it (about halfway through the article): http://www.space.com/23009-spacex-falcon-9-rocket-launch-tes...
I was thinking "barge" at first but if the seas were rough it'd get tossed about and make landing a disaster.
EDIT: It would probably cost millions for all the steel even at salvage value, but that's probably a lot cheaper than the insurance (if you can even buy it) for having a reusable rocket come back over land and attempt a landing, however remote the location.
A barge would not work because it is mobile as well.
This is indeed rocket science.
Since the shuttle's re-entry flightpath is not constrained to restricted airspace, destroying the shuttle orbiter deliberately would only be "range safety" in the loosest sense.
Empirical data seem to suggest Columbia began to self-destruct over the CA/AZ border before landing in a debris field scattered over (populated) west Texas. As seen from an actual destructive episode, the debris path/cone was extensive, and unlikely to be constrained to air-space designated for such purposes.
The issues about how to mitigate this problem comes down to some of the things noted in at least one other comment here--basically SpaceX would limit the re-entry flight-path to open-ocean during approach.
Even then, the question is about ballistic "backstop"/shadow of its landing site ("the beach").
These are pretty basic questions about the size and nature of the landing facility and the ballistic match of un-guided (and potentially un-aerodynamic) debris based upon whatever the realistic assumptions of velocity/altitude and response time of the system are.
The willingness to fly a manned reentering Shuttle Orbiter over populated land without range safety should not be misconstrued as the willingness to drop an unmanned first stage down with engine power without range safety.
They use range safety for launches at those same locations with planned flight paths over the same ocean. I see little reason for them to not use range safety for landings.
With that out of the way, lets look at the issue at hand.
Two issues comprise range-safety and both are at play: (1) is the egineering; and (2) is the flight paths. Proper range safety requires both (1) and (2) combined. The orbiter-as-re-entry vehicle lacked both (1) and (2). Whist the shuttle launch system had them both.
Certainly space X could engineer (1) and (2) using similar techniques at launch with no issue.
The open question is simply providing for range safety for the re-entry/recovery portion of the flight. The shuttle providese little to no road-map in that regards.
Just the opposite: it illustrates some of the difficulties.[0]
Assuming an engineered solution is present (ie, pt1 above) what would the limitations on the flight-patch (ie, pt 2 above) need to be in order that the comination (1,2) together would qualify as "range safety" in the legitimate sense.[1]
The ~rough~ answer seems to be (2') needs to be kept over water/open ocean.
So, my question is more about ballistics math: what is the envelope of precision needed to keep something either (a) in the ocean; and/or (b) out of harms way if the event is triggered closer to land.
The answer to that is something the engineers at SpaceX have surely considered.
I don't know what those calculations show; it (surely) can be safely done up to some threshold.
The question then simply is "what is the threshold"?
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[0] The scale of the debris cone from a columbia's ("natually occurring") event @ 100,000+ ft is illustrative of a couple things. None of: China Lake, White Sands, and Barry Goldwater etc alone could ~readily contain such an event. We know this because all were proximate to the debbris path (ie, western CA, Southern AZ, South/Central NM).
[1] see, eg s.6.2.1 (ff) of this report> http://sites.wff.nasa.gov/multimedia/docs/RangeSafetyManual....
Beyond that, the idea with range safety is to blow it up before it gets to a populated area. Not only to you break the rocket into little pieces, but you do it so that they fall down into the ocean, or on empty ground. Columbia's landing profile didn't allow this (even if it had range safety, which it didn't) but F9-R's certainly ought to, since it's returning over the same empty ocean that it launched over.
FWIW, they haven't announced anything specific about range safety management, but the "Grasshopper" landing test rig was seen rehearsing such a horizontal diversion on one of its last flights.
(As to the barge, its being mobile is a feature, not a bug: they could tow it to whatever spot at sea needs the least fuel to get to after stage separation. The problems are that the barge itself may not stay level during landing, and that the rocket exhaust from even a single throttled-down engine is still likely to burn a hole in a barge.)
Once the bugs have been worked out (if there are any) then you start bringing it back over land.
The tricky part isn't going from 2m/s down to fully stopped and stationary on a launch pad, although I'm sure that's not easy. It's making sure you're completely in control through a whole bunch of maneuvers to transition from heading up very fast to heading back down at a moderate pace to a slowly descending hover. During some of those parts of flight you'll be moving very quickly to where a small sensor lag or instability could make differences measured in miles rather than inches. By putting the whole thing out to sea you eliminate huge swathes of risk be it human life, financial, PR, whatever.
Even if you only did one rig landing and it worked you would gain huge confidence in the systems and you could potentially refuel it on the rig to some amount and fly it back to "base"
Yes, that's true now, but at the height of the Shuttle program, Vandenberg AFB had begun to build, and planned to use, a Shuttle launch facility. So that's a policy change, because there was a time when they were more than willing to launch something very heavy over land to their east.
[1] http://www.spacearchive.info/vafbview.htm "With the exception of the Pegasus XL, all Vandenberg AFB launches take place from the base. Minuteman III missiles climb rather steeply and head due west. Delta, Taurus, and other satellite launch vehicles fly towards the south and climb more slowly."
Vandenberg Air Force Base, in California. The first Falcon 9 v1.1 launch, for CASSIOPE, was from Vandenberg.
Here is a sign that SpaceX has at Vandenberg, implying that they intend to both launch from and land at Vandenberg: http://i.imgur.com/YW4tmkR.jpg
Vandenberg is really only useful for polar orbits, and perhaps retrograde orbits, due to it's high inclination and it's geographical relationship to the ocean.
Similarly, launches from the east coast will land back at the east coast. It will look something like this: http://i.imgur.com/NEi7qKp.jpg (related discussion: http://www.reddit.com/r/spacex/comments/23l96t/spacex_falcon... source: http://www.spacelaunchreport.com/falcon9v1-1.html)
The engineering of the Saturn V just continues to amaze me!
"The engine shutdown was determined to be caused by severe pogo oscillations measured at a strength of 68 g and a frequency of 16 hertz, flexing the thrust frame by 3 inches (76 mm)."
It was this close to ripping the whole rocket apart, but it managed to withstand some incredible shaking until the engine shut down.
One of my friends in Houston was dealing with pogo in rockets specifically. So yes, I am familiar with pogo in general, and I had heard of it during the Apollo program.
An empty booster may have a good enough drag/lift ratio and altitude to get much of the way back by doing a slight turn and 'gliding' with a little help from the engines.
The last two GTO launches did not have reusability test burns because SpaceX was contractually obliged to use all of their delta-v getting the satellites into a highly elliptical orbit (which would allow the satellites to use less of their fuel for the inclination change, thus extending their lifespan). As far as I know, SpaceX only agreed to these sort of terms for those two GTO launches and future GTO launches will still include reusability burn tests.