SpaceX’s Grasshopper Reaches 80 Meters in Flight
McGregor, Texas (SpaceX PR) — SpaceX’s Grasshopper doubled its highest leap to date to rise 24 stories or 80.1 meters (262.8 feet) today, hovering for approximately 34 seconds and landing safely using closed loop thrust vector and throttle control.
Grasshopper touched down with its most accurate precision thus far on the centermost part of the launch pad. At touchdown, the thrust to weight ratio of the vehicle was greater than one, proving a key landing algorithm for Falcon 9. Today’s test was completed at SpaceX’s rocket development facility in McGregor, Texas.
Grasshopper, SpaceX’s vertical and takeoff and landing (VTVL) vehicle, continues SpaceX’s work toward one of its key goals – developing fully and rapidly reusable rockets, a feat that will transform space exploration by radically reducing its cost. With Grasshopper, SpaceX engineers are testing the technology that would enable a launched rocket to land intact, rather than burning up upon reentry to the Earth’s atmosphere.
This is Grasshopper’s fourth in a series of test flights, with each test demonstrating exponential increases in altitude. Last September, Grasshopper flew to 2.5 meters (8.2 feet), in November, it flew to 5.4 meters (17.7 feet) and in December, it flew to 40 meters (131 feet).
Grasshopper stands 10 stories tall and consists of a Falcon 9 rocket first stage tank, Merlin 1D engine, four steel and aluminum landing legs with hydraulic dampers, and a steel support structure.
17 responses to “SpaceX’s Grasshopper Reaches 80 Meters in Flight”
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An AMAZING progression to witness. I would be very interested to learn the plan for the next few steps of Grasshopper’s test sequence. Go SpaceX!!!!
I do wonder if SpaceX have a “master plan” on somebody’s wall somewhere? They appear to be very honest and open anyway and I’m will share there progress “warts and all”.
Doug, do you have any information to share as to why a thrust to weight ratio of the vehicle being greater than one at landing is key to proving the algorithm? I thought a T/W of 1 would be ideal, slightly < 1 would use a little of the landing leg shock absorbers, and anything > 1 is a force greater than that to counteract gravity which would provide upward force. Curious as to why SpaceX wants an upward force at landing. I am pretty ignorant on this topic but interested to learn. Thanks
Hey getitdoneinspace, I’ll do a quick analysis.
You are correct that a T/W>1 would create an upward acceleration, and IF the rocket had zero vertical velocity (e.g., on the launch pad or in a stable hover), then that would result in a net positive velocity and the rocket would ascend.
However, this rocket is descending (a negative velocity) as it nears the ground, at a time when the upward ACCELERATION (of T/W>1) is progressively slowing the downward VELOCITY.of the descending rocket. I think that is exactly where they want to be with it as they tune the thottleable engine for these landings.
THANKS. Learning is a life long experience.
Think of it as the opposite of putting your thumb on the scale. It just means that we did not drop the rocket on the ground.
Anyone notice how the legs are smoking up? That is definitely something they will need to fix for Grasshopper 2.0. Can you imagine how much worse that would have been if they had gone even higher?
Still I am curious how far they can take Grasshopper 1. My bet with this current leg configuration (non retractable legs), they may still be able to get to like 1km. What does everyone else think?
The legs got fairly smokey in the December test, too. It’s possible that while they are indeed getting warm, they’re not getting hot enough to be compromised. Otherwise, yeah, the next test may need a sturdier support frame.
That said, it’s also possible the legs are already experiencing more heat stress than they would on a production VTVL Falcon if it still launches from a pad. In that case, the legs are retracted during ascent, and don’t need to be extended until the last few seconds of descent.
It’s not smoke, it clears too quickly. It looks more like steam. Perhaps condensation from the LOx boil-off before engine start.
Wait. What’s with the guy in the cowboy hat at 1:14? Is that supposed to be Johnny Cash?!?
That is now a tradition (I guess) that was started with the second test of the grasshopper in order to show the scale of the rocket in human terms. For a moment, I thought I was looking at that old video until I noticed how much higher this flight was. So I guess the scale reference must have subliminally worked on me.
Slim Pickens?
Nice test, I do wonder what’s next, retracting legs?
Continue to fly to higher altitudes, decending faster so they can get a feel for the behaviour of the engine when flying into airflow (ie, flying “backwards”, ass first.) Eventually up to the maximum altitude/velocity new first-stage to repeatedly test the reentry manoeuvre.
There’s no need for retracting legs, as such, only “deployable” legs. Which is only necessary when they create a reusable first-stage for actual launches. So it’ll be the last thing on the list.
Quite right Paul451, I must confess to watching Gerry Anderson’s Thunderbirds fro the 60’s.
Anyone know if the same engine is being reused for each of these test flights?
Bob Clark