Grasshopper Takes Highest Flight To Date

Video Caption: On Monday, October 7th, Grasshopper completed its highest leap to date, rising to 744m altitude. The view above is taken from a single camera hexacopter, getting closer to the stage than in any previous flight.

Grasshopper is a 10-story Vertical Takeoff Vertical Landing (VTVL) vehicle designed to test the technologies needed to return a rocket back to Earth intact. While most rockets are designed to burn up on atmosphere reentry, SpaceX rockets are being designed not only to withstand reentry, but also to return to the launch pad for a vertical landing. The Grasshopper VTVL vehicle represents a critical step towards this goal.

Grasshopper 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.

  • Kam Chuanhui

    From 1:00 onwards as Grasshopper descents, the flames seems to be licking the base extensively. Is it normal and will this damage the F9?

  • Christopher James Huff

    Remember, during launch, the bottom of the rocket has to take the radiant heat from the main exhaust of 9 engines, and the heat from the engines themselves. The sooty orange exhaust from one turbopump probably isn’t a huge issue, especially with the limited duration of exposure.

    Also, the Falcon 9-R likely won’t need to hover around like this. There’s no reason to stop in mid air, so it’ll probably have more airflow to sweep the flames away and even less time exposed to them.

  • therealdmt

    But, as he says, there will be a descent stage of the flight where the base will be subject to these flames blowing back somewhat towards the nozzles and other parts and the structure at the bottom of the rocket.

    It’ll be one thing (an impressive thing!) to land a first stage after it boosts an upper stage/payload to space. It’ll be another thing to then refurbish it and successfully re-use that first stage. And it’ll be still another thing to do that at a cost savings over just building a new first stage. Finally, how many times can it be re-used? The bottom of that rocket is definitely taking some abuse.

    But I’m an optimist on this — I’m really looking forward to major progress on the Falcon 9R over 2014.

  • therealdmt

    So there’s still a structure around the base of the rocket. The article says its a Merlin 1D engine, so that’s the new engine. And the legs look like the new landing legs (maybe?), but in a fixed structure. Or is it just the same ol’ grasshopper we’ve come to know and love?

  • Hug Doug

    this still the same old Grasshopper 1.0, it’s been running with a Merlin 1D for all 8 of its launches. compare some old pictures of it with the video, it’s still the same landing legs it’s always been using.

    the Grasshopper v1.1 is built around the stretched tank of the Falcon 9 v1.1, and that one will have the new retractable landing legs. test flights of that vehicle should begin within the next few months, at Spaceport America in New Mexico.

  • therealdmt

    Right, I remember that about the new Grasshopper supposed to be being based out of New Mexico.

  • therealdmt

    744 meters = 2,441 ft., for my fellow pilots out there.

  • Aerospike

    I’m not sure, that there will be a “Grasshopper v1.1”. On Facebook, they added the following Info to the video caption:
    “This was the last scheduled test for the Grasshopper rig; next up will be low altitude tests of the Falcon 9 Reusable (F9R) evelopment vehicle in Texas followed by high altitude testing in New Mexico.”

    Looks like we are going to see the “real” F9R landing legs pretty soon? 🙂

  • Tonya

    I think they are referring to the the same vehicle, but they’ve chosen not to continue the Grasshopper name as it’s now so close in configuration to the final design.

    One difference would be whether it has a full set of engines, or just one (maybe three) and the rest are ballast.

  • Michael Vaicaitis

    It seems perfectly reasonable to believe that the engines could last at least 10 mission durations, perhaps replacing the centre engine more frequently. Also, there’s no reason that the core shouldn’t last many many more uses, and I bet it’s much more costly than an engine.

    Most importantly though, by getting back a first stage intact by propulsively landing, just once, will give them a hugely significant opportunity to closely inspect every component and review design choices. Each subsequent landing allows them to hone component and design choices, towards a best compromise between manufacturing/maintenance cost and durability, to deliver the best per launch cost. Basically, getting the thing back is the key to continually improving the system.

    I realise Raptor is reported as intended for MCT and/or upper-stage, but we might also expect, at some later date, a staged combustion methane fuelled Merlin replacement. This would lack the gas generator exhaust and the cleaner combustion should result in greater engine longevity. Additionally, it allows them to focus their main engine R&D on a single fuel type. Furthermore, methane is cheaper and greener which is in line with Elon Musk’s sustainability credentials and at the same time, good for everyone.

  • dr

    What I noticed on this flight, was that the landing gear didn’t seem to be smoking like usual. On some previous flights their has been smoke billowing from the gear. So I guess that some small changes have been made to Grasshopper between the last flight and this one.

  • Christopher James Huff

    Read my post again. I know there’s a descent phase, I’m saying the thermal environment is probably worse during ascent…you know, with 9 plumes of burning LOX and RP-1 coming out of the bottom for a couple minutes.

    And you’re worried about the engine nozzles? They have to deal with *much* worse during launch. This isn’t a jet of dense, hot, fast-moving rocket exhaust. It’s a low temperature flame intermittently brushing against the bottom of the craft largely under natural convection. You can easily protect against a few seconds of exposure to this sort of flame, the most significant impact is probably the soot it’ll get all over the place.

  • DougSpace

    Hey guys. Why is there only a significnt amount of smoke at takeoff and landing?

  • mfck

    dust…?

  • Hug Doug

    Yes, according to that post this is the last flight of the Grasshopper 1.0. It makes sense that the Falcon 9 Reusable “development vehicle” will be the Grasshopper v1.1. Previous statements have said that it will be tested with “flight like” legs, and the tests done / lessons learned with the development vehicle will be applied to the actual flight version of the F9R.

  • DougSpace

    Would there really be that much dust on the pad and would it still be there after being blown away from take-off?

  • Hug Doug

    most of it is coming from the dirt around the launch pad.

  • mattmcc80

    Bearing in mind that the Grasshopper’s legs and related structure aren’t anything close to the legs of the production F9R. In the F9R, they’re flush against the core during launch and most of the reentry, not being extended until they’re needed. They’ll be well away from the engine exhaust most of the time. Interestingly, the legs on the F9R are also supposed to serve an aerodynamic purpose on reentry (probably providing some air resistance to reduce the fuel needed)

  • Hug Doug

    It’s worth mentioning that those flames are from the turbopump exhaust, and are not the flames from the rocket engine. they are a much less intense flame.

  • Chris Courtois

    Question… are they using the turbopump’s exhaust as attitude control? Wonder if it’s strong enough to help with that. If so, it would show how they’re optimizing this system by “recycling” an exhaust’s thrust that other rockets would just be tossing out.

  • Hug Doug

    well, the thrust produced by the turbopump exhaust does give a very small boost to the overall thrust of the engine, so there’s that. but it’s not much compared to the power from the engine itself.

    turbopumps are meant to pump fuel into the engine with the greatest possible efficiency. they are exceedingly difficult to design well. they’re by far the trickiest part of a rocket engine. the Soviet NK-33, the Space Shuttle’s SSMEs and other staged combustion rocket engines feed the turbopump exhaust back into the combustion chamber, giving these engines dramatic boosts in efficiency and power, but the problem with that is, a stable fuel flow from two sources is very difficult to achieve. this is why SpaceX did not go for a staged combustion engine.

    it’s no understatement to say that turbopump design is the most difficult thing in the already complex field of rocket science. making the turbopump do something else (such as RCS) would likely decrease its efficiency, which would decrease the power of the engine overall.

  • savuporo

    Thats 7860ft lower altitude than DC-X did.

  • Chris Courtois

    It’s hard to see on the videos, but I could swear I see a gimbal mechanism right on the generator’s exhaust. Even if the thrust isn’t much, as a secondary force it probably can help with roll control and attitude. The reason why I think this is, they’ve super-optimized this design somewhere to get so efficient. I’m thinking using the gas gen for attitude control (and not for lift, just control) would be a great way to optimize fuel use, saving the need for added roll/attitude control thrusters, or at least requiring less of them.

  • Hug Doug

    the way the Falcon 9 v1.1 engines are laid out right now, i don’t think you could use them for RCS anyway. the holes for the turbopump exhaust are on the inside of the ring of engines.

    http://www.raumfahrer.net/forum/yabbfiles/Attachments/up030085.jpg

  • Chris Courtois

    Hey thanks! That sort of solves it for me… clearly they’re NOT using it for RCS! Funny though, I’ve seen this pic before and it didn’t click right away. It’s pretty darn clear!

  • Hug Doug

    Thank you for the productive discussion!

  • Chris Courtois

    Anytime 😉 Gotta love hanging out online with the “Parabolic Arc gang” Hehehe