backtop


Print 32 comment(s) - last by delphinus100.. on Mar 15 at 10:07 PM

The Grasshopper lifted to 24 stories (262.8 feet) off the ground

SpaceX took its reusable Grasshopper rocket for another hop last week at the South by Southwest festival in Texas.

SpaceX CEO Elon Musk was there to demonstrate the Grasshopper's fourth test flight, which was twice as high as the reusable rocket has ever gone in previous demonstrations.

"Grasshopper touched down with its most accurate thus far on the centermost part of the launch pad," said SpaceX. "At touchdown, the thrust-to-weight ratio of the vehicle was greater than one, proving a key landing algorithm for Falcon 9."

The Grasshopper lifted to 24 stories (262.8 feet) off the ground, hovered for about 34 seconds and then landed safely back on the ground.

The Grasshopper is a Falcon first stage with a landing gear that's capable of taking off and landing vertically. It does this by shooting into orbit, turning around, restarting the engine, heading back to the launch site, changing its direction and deploying the landing gear. The end result is a vertical landing.

The reusable rocket was tested in September, November, December and last week Thursday.

Check out this video of Thursday's demonstration:

Source: NBC News



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: amazing
By Solandri on 3/11/2013 9:22:37 PM , Rating: 2
As far as reusable spacecraft go, the Space Shuttle had the right idea. You injected gobs of energy into the spacecraft to put it into orbit. Instead of bleeding it all off during descent, save some of it so you can glide to a landing.

I'm not sure what the goal of terrestrial rocket which lands upright is, aside from proof of concept. You're going to pump a lot of energy into it to put it into orbit. Then you're going to bleed all that energy off to get it out of orbit. Then you're going to use up more energy to bring it to a safe landing?

From an energy consumption standpoint, a glider landing or even a powered aerodynamic flight landing is preferable. Unless they've done calcs which say the energy cost of carrying the weight of the wings exceeds the energy cost of a powered landing. I suspect the most energy efficient way to travel to space and return is to take-off like a plane and fly to altitude, use rockets to get into orbit, use atmospheric drag to get out of orbit, then fly to a landing like a plane.


RE: amazing
By garidan on 3/11/2013 10:34:19 PM , Rating: 2
Wings are heavy and have no use to go up, they are air breaks even.
A rocket weights a lot, has it's own engines and doesn't need a plane which should anyway be very very big to lift it just to reach 20Km of height, on the way to 200km and beyond to orbit.

The beauty of the SpaceX plan is that all the weight you put for reuse is almost due to fuel, so that it becomes a safety margin too in case of problems at launch.
Do you have an engine out, you use more fuel and complete mission, and sacrifice that core for reuse.
And it scales very well for their Falcon Heavy, where they aim to use the same "technique" to recover the side boosters and core, something wings would not allow.

They are doing well, the first next launch with their new Falcon 1.1 rocket they'll test the first stage turn around (using cold gas) and reignition to break and try a "land" test on the ocean.
See NASA forum http://forum.nasaspaceflight.com/index.php?topic=2...


RE: amazing
By mjv.theory on 3/12/2013 5:00:21 AM , Rating: 2
quote:
As far as reusable spacecraft go, the Space Shuttle had the right idea.

I never saw the videos of the enormous external tank making an intact landing.

The fuel required to get 200miles up is only about 10% of the total. Most of the fuel is used to get to 7500m/s: orbital "velocity" - essentially you are not so much trying to go UP, as go FAST. This is what makes a staged rocket more mass efficient than a SSTO.

quote:
I suspect the most energy efficient way to travel to space and return is to take-off like a plane and fly to altitude, use rockets to get into orbit, use atmospheric drag to get out of orbit, then fly to a landing like a plane.

Using conventional rockets engines, this is incorrect. Something along the lines of Reaction Engines plans with Skylon, using their Sabre engines would be required. Also consider, wings are likely more of a liability during re-entry.

The fuel required to get 200miles up is only about 10-15% of the total. Most of the fuel is used to get to 7500m/s: orbital "velocity" - essentially you are not so much trying to go UP, as go FAST. This is what makes a staged rocket more mass efficient than a SSTO design (single stage to orbit). I suspect that a staged VTOL system like Falcon 9 might well also benefit from Sabre-like engines and eventually be the optimal solution.


RE: amazing
By JediJeb on 3/12/2013 10:58:13 PM , Rating: 2
Consider using this in places where there is no atmosphere for a glider to work(Moon, Mars to some extent, Jovian moons, ect) it would be the only way of landing and relaunching. It is definitely some good research for future projects.


RE: amazing
By delphinus100 on 3/15/2013 10:00:47 PM , Rating: 2
quote:
As far as reusable spacecraft go, the Space Shuttle had the right idea. You injected gobs of energy into the spacecraft to put it into orbit. Instead of bleeding it all off during descent, save some of it so you can glide to a landing.


Vertical landing concepts (not just a recoverable Falcon stage, this goes way back) don't try to decelerate all the way from LEO (it would take as much energy as to get there..and imagine putting a vehicle that big into orbit to begin with). Conventional aerobraking as we've always seen it, is done (after a retroburn that anyone must do, to dip the low point of your orbit into the atmosphere), until the vehicle slows itself to whatever its terminal velocity is. You need only enough propellant to decelerate from that to zero, and you air-start the engines at the right time to reach zero velocity at the surface.

What? Air-start of engines makes you nervous? The flip side is that a winged orbiter is a glider that must reach a runway of minimum length, and has only one pass st it.

Or go back to capsules whose parachutes must open properly, every time. (Soyuz-1, anyone?)

You pays your money and makes your choice...


"We basically took a look at this situation and said, this is bullshit." -- Newegg Chief Legal Officer Lee Cheng's take on patent troll Soverain

Related Articles













botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki