Discussion SpaceX's Grasshopper RLV
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Cosmic Penguin
Geek Penguin in GTO
Yesterday the Grasshopper flew out what we now call the "Proton maneuver", intentionally flying laterally for 100m while reaching a height of 250m: :thumbup:
indy91
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Is there a Grasshopper addon for Orbiter in the works, or already released? That would be awesome, but I can't find anything...
Donamy
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computerx did a nice job with one of his addons, shown in these two videos.
https://www.youtube.com/watch?v=ylKDKcelNYo
https://www.youtube.com/watch?v=wjEwutpmHRE
Urwumpe
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I dislike the spherical dust cloud particles there, these look a bit strange...maybe a more dynamic texture could help.
Also the relation between engine distance and particle density and particle velocity is different.
Andy44
owner: Oil Creek Astronautix
IIRC computerex turned around the request for that dust addon in less than 24 hours, as was his way for a time. I think making the dust particles smaller started to tax the frame rate or something.
That last Grashopper video is astonishing.
That last Grashopper video is astonishing.
Thunder Chicken
Fine Threads since 2008
Yes it is. I am impressed. I'm wondering if they are planning a flight of the Grasshopper where they will fly it out to the altitude/downrange/velocity point where the first stage jettison would normally occur, and then fly that back. They are getting close to that capability.
I had initially wondered about fuel slosh and CG in this stage being a problem, but the more I think about it, ullage should be OK. At every point from MECO through RTLS and touchdown the fuel will be pressed to the bottom of the tank, and the stage should be able to orient and fire without fighting any sort of windsocking - the windsocking actually helps. The engines and fuel at the bottom of the stage, and a emptying upper tank that will serve as tailfeathers.
Every Falcon 9 flight from now on, starting with the September 5 launch of the Cassiope sattelite for the CSA, will feature a propulsive-return over-water test -- basically a return to hover over water -- after payload jettison. They expect problems, but are pretty confident that by 2015, they'll be returning the first stage to land.
Thunder Chicken
Fine Threads since 2008
Maybe, but doesn't this 1) severely restrict possible orbit inclination and 2) require reshipment of stages back to the launch site?
RTLS might incur a slight energy penalty, but it removes the above issues.
Did a quick calculation by watching one of the launch videos and listening to the telemetry read-outs. The upshot is that with a purely ballistic trajectory after 1st stage sep, the stage would only land 600 km or so downrange (and air resistance would mitigate even that distance), so a landing at KSC from a VAFB take-off is probably not a possibility.
Landing at a first stage at KSC after a launch from VAFB is NO-GO as all launches from VAFB go south, over the Pacific. This is due to overflights of inhabited land is strictly prohibited.
In order to to reach KSC from VAFB within a single orbit, it must be launched towards the east which puts the flightpath over most of CONUS. I don't know about you, but I think that a majority of the population would not want something that's powered by something that can only be described as "controlled explosions" flying over them.
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