The rocket is able to initiate a controlled descent back to the ground. Image Credit: SpaceX / YouTube
A remarkable new type of reusable rocket could soon revolutionize how we launch things in to space.
SpaceX's Grasshopper rocket might at first glance appear to be like any other, but what it lacks in visual uniqueness it makes up for in innovation. Unlike conventional chemical rockets, the Grasshopper will be able to launch, deliver its payload and then land again in a vertical position.
In an impressive demonstration flight this week, the rocket took off from SpaceX's test pad in McGregor, Texas and flew to a height of half a mile before returning to the ground in a controlled descent that saw it land on the exact spot from which it had launched.
While conventional first-stage rockets are simply jettisoned and can only be used once, the Grasshopper has the potential to provide a long-term reusable solution that could change the way we put things in to space.
An impressive video of the test flight taken from a remote-controlled hexacopter hovering nearby has been released online and can be viewed below.
While I applaud the desire to innovate, there are several major obstacles to this becoming a de facto standard for future launches. Probably the greatest of those obstacles would be cost - not just in monetary terms, but also in fuel. The rocket has no glide-flight characteristics, therefore both the ascent and descent are completely dependent on thrust from it's primary engine(s). This requires nearly (and possibly more than) double the fuel payload the launch of an expendable rocket of comparable size (minus the weight of cargo expelled before re-entry) requires. Because more fuel needs to b... [More]
The question is, can the booster engine be re-used? That is in the Critical Path for cost effectiveness. Lets not forget that 744metres altitude does not equate to a re-entry burn, as ablation shielding is not required. I believe that this was just a simple Proof of Concept for the Avionics, nothing more. Apart from which the new Sabre engine is is truly designed for re-use from an HTOL viewpoint dramatically reducing the costs involved with conventional Space Delivery Systems
The question is, can the booster engine be re-used? That is in the Critical Path for cost effectiveness. Lets not forget that 744metres altitude does not equate to a re-entry burn, as ablation shielding is not required. I believe that this was just a simple Proof of Concept for the Avionics, nothing more. Apart from which the new Sabre engine is is truly designed for re-use from an HTOL viewpoint dramatically reducing the costs involved with conventional Space Delivery Systems The vehicle shown is a proof of concept and not meant to deliver payload into orbit and there must be substantial savi... [More]
I believe that this was just a simple Proof of Concept for the Avionics, nothing more. You seem to be making the same incorrect assumption that Leonardo is (or rather one of his incorrect assumptions as there are several but I will address that later). The Grasshopper is a test bed for a modification of the existing Falcon 9 first stage. As such this represents more than a simple proof of concept for the avionics. The Grasshopper is essentially a Falcon 9 first stage with only 1 (instead of 9) Merlin 1D engines. The next version of Grasshopper will use all 9 engines and will have legs which ar... [More]
Thanks for the additional info, Waspie. I can see where the assumptions I made might have led me astray, although I still have reservations regarding the reliability of the approach. I'm glad they are experimenting in the hope of achieving their projected goal, but am skeptical they will achieve it.
The rocket has no glide-flight characteristics, therefore both the ascent and descent are completely dependent on thrust from it's primary engine(s). Not so. No vehicle needs thrust to descend, gravity takes care of that. What you need is thrust to break the vehicle and allow it to land. This requires nearly (and possibly more than) double the fuel payload the launch of an expendable rocket of comparable size (minus the weight of cargo expelled before re-entry) requires. Where did you get that figure from? Firstly that is not the way it works. The vehicle size (and therefore fuel load) is the ... [More]
Thanks for the additional info, Waspie. I can see where the assumptions I made might have led me astray Hi Leonardo, sorry for the post coming after yours, I wasn't intending to put the boot in, I was already in the middle of writing it and it seemed a shame to waste it. although I still have reservations regarding the reliability of the approach. I'm glad they are experimenting in the hope of achieving their projected goal, but am skeptical they will achieve it. I think the advantage they have is that they are modifying existing technologies rather than building something new and complex. The... [More]
I am not an MechEng, so perhaps I am missing the obvious. But, wouldn't it be far less costly and simpler to use an enhanced parachute system. Or, perhaps parachute and some thrust e.g. JATO/RATO at near touchdown.
I am not an MechEng, so perhaps I am missing the obvious. But, wouldn't it be far less costly and simpler to use an enhanced parachute system. Or, perhaps parachute and some thrust e.g. JATO/RATO at near touchdown. Parachutes still add weight. The parachutes needed to lower the speed of a Falcon 9 v1.1 first stage which weighs over 25 tons would need to be massive and therefore heavy. Unless you are planning to land at sea (like the shuttle SRBs) then you are still going to need to manoeuvre the vehicle at supersonic speed back over land, which requires engine thrust. Parachute's alone could n... [More]
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