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The Grasshopper Can Fly Sideways

timothy posted about a year ago | from the that's-how-they-sneak-up-on-you dept.

Space 127

Phoghat writes "I'm of a 'certain age' and as a child grew up watching shows like "Rocky Jones, Space Ranger and others popular at the dawn of the space age. They always showed rocket ships sitting on their tails and blasting off, and landing, straight up. The shuttle went up that way but had to land like a plane, and anything else was considered impossible or impractical. Now, the Space X's rocket Grasshopper can not only do that, but has demonstrated sideways flight also."

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127 comments

Actually not a dupe! (2, Insightful)

OzPeter (195038) | about a year ago | (#44572427)

I almost called dupe from SpaceX Grasshopper Launch Filmed From Drone Helicopter [slashdot.org] but this is new stuff.

Re:Actually not a dupe! (0)

BitZtream (692029) | about a year ago | (#44574151)

Its not actually new either. Grasshopper is hardly the first craft, space craft or otherwise to move horizontally when it was vertically oriented. Its not even really impressive that they got it to work on the grasshopper. NASA sent a rover to mars and did it right on the first (and only) try, or you could look at the apollo program moon landers.

Big deal, SpaceX found out they could mod an ardupilot fairly easy to make their rockets navigate horizontally. When guys playing with toys (I'm one of those types of guys ;) can do it, your big billion dollar space ship doing it is hardly impressive.

Re:Actually not a dupe! (4, Insightful)

amicusNYCL (1538833) | about a year ago | (#44574545)

The way I see it, it's not so much that they can launch a vehicle vertically and then move it horizontally. The impressive part is that they do it with an actual rocket that is 106 feet tall, and that they have launched it 7 times with 0 failures. And this is all in prelude to their 9-engine 160-foot tall rocket that they will test at altitudes of up to 300,000 feet. When you have that working in your backyard, you let us know and we'll be happy to pat you on the back. Or, if you're as competent at designing rocket control systems as you seem to think, go ahead and work for them. I'm sure Elon Musk pays his people well.

Re:Actually not a dupe! (0)

Anonymous Coward | about a year ago | (#44575279)

NASA has sent more than one lander/rover to Mars, so it not their first/only try. Not all of the missions have been succesful, either, although some of those were the rover's fault.

Re:Actually not a dupe! (2)

mbkennel (97636) | about a year ago | (#44575327)

"When guys playing with toys (I'm one of those types of guys ;) can do it, your big billion dollar space ship doing it is hardly impressive."

Yes it is.

The ratio of control forces to mass is much smaller on a big rocket, and the ratio of money lost per bug is much much higher. And they got it to go sideways and back the same amount and hit a calibrated target.

I can set up a web server by installing 5 standard linux packages. Does this meant that Google's search infrastructure is no big deal?

Scale-up, commercialization and having a hundred million dollars riding on your software really is a big deal.

Re:Actually not a dupe! (1)

c++0xFF (1758032) | about a year ago | (#44575567)

What makes this different is the 10 story rocket. The LEM was 18 ft tall. The Sky Crane was probably about the same, if not smaller. The scale here makes your "toys" kinda pathetic ... it's clearly not the same by any means.

This is just a baby step to doing the whole thing from orbit, starting from hypersonic velocities (although I think a heat shield and parachutes do a significant amount of work before the rockets kick in).

This project is ramping up to be something really impressive.

Yes, it is impractical (5, Informative)

Anonymous Coward | about a year ago | (#44572445)

"The shuttle went up that way but had to land like a plane, and anything else was considered impossible or impractical."

XKCD just covered this! [xkcd.com] Good timing for the question.

TL;DR: Heat shields aren't going away because they are efficient.

Re:Yes, it is impractical (5, Informative)

Anonymous Coward | about a year ago | (#44572523)

TL;DR: Heat shields aren't going away because they are efficient.

And the rocket equation is not. People need to be aware what they are looking at in these videos. This is not a spacecraft coming back to the Earth to land after it did some awesome mission. It is a depleted lower stage of a rocket, where the upper stage(s) has separated and continued on. Now the light lower stage has just enough fuel to fly home (because it is so light after burning up most of its fuel). It is a really, really clever idea for reusable lower stages. But it does not allow rockets to reenter the Earth's atmosphere at orbital velocities, slow down, and land. A phrase scientists and engineers use when they talk about the rocket equation is tyranny [nasa.gov] . Tyranny is right. It took a rocket the size of a skyscraper and weighing as much as a diesel submarine to go to the Moon and back. Without the heat shield, the rocket would have to be the size of an aircraft carrier.

Re:Yes, it is impractical (2)

Tx (96709) | about a year ago | (#44572597)

+1 Informative, but boy, would I have liked to see a rocket the size of an aircraft carrier!

Re: Yes, it is impractical (0)

Anonymous Coward | about a year ago | (#44572701)

You already have. At just over 1000 feet long, aircraft carriers are about the size of a skyscraper if stood on end. Some skyscrapers are bigger than aircraft carriers.

Re: Yes, it is impractical (1)

Anonymous Coward | about a year ago | (#44572761)

Except a Saturn V was only 300 ish feet tall. Better comparison would be to say rockets are about the same size and weight as a submarine and leave skyscrapers out of it.

Re: Yes, it is impractical (1)

dywolf (2673597) | about a year ago | (#44573311)

most modern skyscrapers are still under 1000 feet tall. It was only the record breakers that really got that high. most high rise buildings (sky scrapers) are between 300 and 800 feet tall, so the comparison is still apt.

Re: Yes, it is impractical (0)

Anonymous Coward | about a year ago | (#44573503)

And most rockets are under 300 ft tall, only the record breakers are over 300 ft. So the comparison is not apt. Record to record, or average to average. Pick one.

Re: Yes, it is impractical (0)

Anonymous Coward | about a year ago | (#44574517)

He's comparing a specific object (the Saturn V) with a class of objects (skyscrapers). It wouldn't be wrong to compare huge solar panels to, say, soccer pitches just because you're using typical pitches but unusual solar panels.

Re: Yes, it is impractical (1)

Anonymous Coward | about a year ago | (#44573709)

How about... if you want to go to space, stand on top of a smaller skyscraper. You end up in a capsule about the size of the antenna on top. The rest of the building is rocket fuel.

Re:Yes, it is impractical (1)

taiwanjohn (103839) | about a year ago | (#44572961)

Here ya' go... [wikipedia.org]

Re:Yes, it is impractical (1)

Anonymous Coward | about a year ago | (#44572973)

Let's do a rough estimate. You would need to lift a return rocket roughly the size of a Saturn IB into orbit (which has a mass of 590 tonnes) plus your mission mass of 50 tonnes or so. There is one rocket [wikipedia.org] that might be able to do it, with a little upgrading: the Sea Dragon. In the early 1960s NASA wanted to figure out how to go to Mars. Someone did the math and learned that heavy lifting capability was the key factor and designed a rocket for it that would be built in a shipyard, towed out to sea, ballasted properly, and then launched at sea (with a nuclear aircraft carrier as a tender that would supply it with H2 and O2 via hydrolysis). I think I can honestly say that it would have been the greatest thing ever.

Re:Yes, it is impractical (1)

Holi (250190) | about a year ago | (#44573179)

No it took a rocket the size of a skyscraper and weighing as much as a diesel submarine to get a tiny capsule to the moon. The rocket itself was destroyed in the process.

Re:Yes, it is impractical (1)

AJWM (19027) | about a year ago | (#44574421)

The Saturn V had a payload to Earth orbit of 260,000 lb, which happens to be the weight of a fully-fueled Atlas missile. So in theory the Saturn V could orbit a vehicle which could use rocket braking to de-orbit and land without a heat shield.

Impractical as hell, of course.

Heck, even in my fictional future T-space stories, where we have warp, fusion, but no anti-gravity*, ships tend to use aerobraking. (Given the ridiculously high power and Isp of their thrusters, they could do a retrofire to landing, but generally don't. Tradition. Also helpful if you've about run out of fuel.)

*(In theory if you can bend space for a warp drive you can unbend it for anti-grav, but my stories take place in early days when humans haven't figured out how to do that yet. The pioneer in such technology suffered a rather messy accidental death while testing.)

Re:Yes, it is impractical (1)

Xaedalus (1192463) | about a year ago | (#44575087)

Ya know, if you ever felt like writing some humor, you could come up with a couple of scenarios on anti-grav testing. I think you could probably come up with some hilarious yet believable testing scenarios that don't involve messy death.

The first stage is suborbital. (5, Interesting)

ClayJar (126217) | about a year ago | (#44572559)

Heat shields are the efficient way to slow from orbital speeds for reentry (e.g. the Shuttle), but conveniently for recovery the first stage isn't orbital. Grasshopper is basically a modified Falcon 9 first stage, and the goal of the testing is recovery of the first stage of Falcon 9-R, which is much easier than reentry from orbit..

We're not talking single stage to orbit here, and recovery of the second stage would certainly involve a heat shield. The first stage is a different animal. SpaceX seems to be intending to use a boost-back trajectory concept. I look forward to seeing how that works. (The controlled water "landing" attempt will be something to see, too, of course.)

Re:The first stage is suborbital. (2)

taiwanjohn (103839) | about a year ago | (#44572681)

Even if they never succeed at recovering the second stage, just reusing the first stage could cut the cost per flight in half, if not more. But they seem to be making pretty good progress thus far, and Musk has said he hopes to attempt a 1st-stage recovery as early as next spring. So I wouldn't be surprised to see them succeed with the 2nd stage too.

Here's a video of the shceme. [youtube.com]

Re:The first stage is suborbital. (1)

digitalchinky (650880) | about a year ago | (#44573523)

Pretty good progress thus far? I'm inclined to add a few 4 letter expletives in amongst those words, that video left me staring in awe. : ) A few days back we had a video about an autonomous quadcopter thing that spent the better part of 10 minutes randomly turning in circles as it wandered through a building mock-up. This thing jumps up a few hundred feet vertically and horizontally away from the pad and then drops back down like a boss, utter perfection from my armchair.

Re:The first stage is suborbital. (2)

taiwanjohn (103839) | about a year ago | (#44575835)

I'm inclined to add a few 4 letter expletives in amongst those words

You'll get no argument from me. Musk has had a hell of a run the last couple of years, and from my chair here it looks like he's just getting warmed up.

And it's not just him... there's a ton of cool stuff in the pipeline over the next few years. There's half a dozen other players in the "NewSpace" market, such as Masten, Sierra Nevada, XCOR, MoonEx... And these will enable further ventures such as Planetary Resources and Deep Space Industries.

And it's not just in space... We're going to have grid-level electricity storage on the market within the next couple of years, in multiple [youtube.com] forms. [youtube.com] That alone will make energy cheaper and easier to manage, not to mention all the new "alternative" energy sources under development, too numerous to list, any one of which could be a game changer, at least to some degree.

We live in "interesting times" indeed.

Re:Yes, it is impractical (1)

nedlohs (1335013) | about a year ago | (#44573007)

You can use the atmosphere to slow down without having landing as a plane.

See basically everything but the space shuttle that has gone into orbit and returned to earth.

Doesn't mean you want to use a rocket rather than a wing or parachute of course, but doing so does not mean you don't use the amosphere to shed as much velocity as possible.

Re:Yes, it is impractical (1)

Megane (129182) | about a year ago | (#44573715)

Note that Grasshopper does NOT have to return from orbital velocity. It has to fight whatever horizontal vector the first stage got from its primary job of launching the vehicle, but that's nowhere near orbital speed. So it doesn't have to worry about all the fun of orbital re-entry.

Also, the main job of Grasshopper is to go down to a controlled landing. It doesn't need to be able to go full sideways like the DC-X did. It just tilts itself in the general direction of where it needs to go vertical.

Gravity pulls toward the Earth (1)

jfdavis668 (1414919) | about a year ago | (#44572451)

And a rocket's motor is at the back. Of course it is going to point down to counteract. No matter which way you point the rocket, the motor must point mostly down.

Re:Gravity pulls toward the Earth (3, Informative)

i kan reed (749298) | about a year ago | (#44572511)

Actually, pretty quickly after takeoff, a rocket's inclination is changed to 25ish degrees. If you just go straight up, you're just going to fall back to earth and never achieve orbit.

Re:Gravity pulls toward the Earth (2)

SJHillman (1966756) | about a year ago | (#44572583)

Are we talking 25 degrees off an axis perpendicular to the ground or parallel to the ground? Because the former is still close enough to the perpendicular to be considered pointing "mostly down" rather than "mostly sideways" or, if NASA copies my Kerbal designs, "mostly up, no over, no down, no up again".

Re:Gravity pulls toward the Earth (1)

taiwanjohn (103839) | about a year ago | (#44572721)

No, it's 25deg above the horizontal. The point is to increase your "sideways" velocity parallel to the earth's surface, which (in space) is what really determines the height of your orbit.

Re:Gravity pulls toward the Earth (2)

david.given (6740) | about a year ago | (#44573147)

Note that in real life you do the gravity roll much earlier than you do in KSP --- this is to get the vehicle clear of the launchpad so that if you're not going to space today, the debris doesn't land on your technicians.

In KSP you leave the gravity roll quite late so that you waste as little fuel as possible pushing through the dense part of the atmosphere (I usually do it at 15km).

Re:Gravity pulls toward the Earth (1)

Rhacman (1528815) | about a year ago | (#44574519)

Ahh, see NOW you're talking my language! Come to think of it, most of the junk from my failed KSP launches has been raining down all over the Kerbal Space Center.

Re:Gravity pulls toward the Earth (1)

david.given (6740) | about a year ago | (#44575459)

That's half the fun!

Re:Gravity pulls toward the Earth (1)

lgw (121541) | about a year ago | (#44575785)

I should really make time to play with KSP. Can you put a RSD on those rockets? I mean I'm sure enough of them blow up on their own, but blowing them up on command seems fun as well. Why do I have this feeling my game will end when I get lynched by Kerbals?

Re:Gravity pulls toward the Earth (1)

vux984 (928602) | about a year ago | (#44575569)

if NASA copies my Kerbal designs

Aren't those the six words words you never say at NASA?

http://xkcd.com/1244/ [xkcd.com]

Re:Gravity pulls toward the Earth (1)

rossdee (243626) | about a year ago | (#44573067)

" If you just go straight up, you're just going to fall back to earth and never achieve orbit."

If you have an efficient enough rocket (not chemically powered) you can achieve escape velocity by going straight up, then you will never fall down (to the earth) again.

Re:Gravity pulls toward the Earth (1)

ibwolf (126465) | about a year ago | (#44573913)

If you just go straight up, you're just going to fall back to earth and never achieve orbit.

If you have an efficient enough rocket (not chemically powered) you can achieve escape velocity by going straight up, then you will never fall down (to the earth) again.

While true, you'll also never achieve orbit going straight up.

I have mixed feelings (0)

Anonymous Coward | about a year ago | (#44572475)

One the one hand, this is a big step for SpaceX in developing a reuseable rocket booster. Kudos.

On the other hand; been there, done that [youtube.com] .

PHILIP K DICK PREDICTED THIS! (1)

Thud457 (234763) | about a year ago | (#44572883)

The Grasshopper Flies, Heavy, Man!

burbleburbleburble...

Did SpaceX take on anybody from Armadillo? (2)

szquirrel (140575) | about a year ago | (#44572477)

When I see vertical-takeoff-vertical-landing my first thought is Armadillo Aerospace and their years of work on those rockets. Now that Armadillo is largely mothballed, have some of their guys turned up at SpaceX?

Re:Did SpaceX take on anybody from Armadillo? (1)

samkass (174571) | about a year ago | (#44572777)

And are these the same guys who worked on DC-X and DC-Y [wikipedia.org] back in the day which also achieved Grasshopper's same milestones 20 years ago?

Re:Did SpaceX take on anybody from Armadillo? (1)

dywolf (2673597) | about a year ago | (#44573263)

Nice, you can link to wikipedia.
Now try reading it.

the DCX and DCY were not reusable launchers/stages.
they were intended as entirely reusable Single Stage to Orbit (SSTO) vehicles. By comparison grasshopper is testing many things, but the most important aspect is the concept of a reusable launcher seperate from the actual vehicle put into orbit.

They also had a completely different designed flight profile and capabilities (never tested as the project never got that far). specifically, this:

One desired safety requirement for any spacecraft is the ability to "abort once around", that is, to return for a landing after a single orbit. Since a typical low earth orbit takes about 90 to 120 minutes, the Earth will rotate to the east about 20 to 30 degrees in that time; or for a launch from the southern United States, about 1,500 miles (2,400 km). If the spacecraft is launched to the east this does not present a problem, but for the polar orbits required of military spacecraft, when the orbit is complete the spacecraft overflies a point far to the west of the launch site. In order to land back at the launch site, the craft needs to have considerable cross-range maneuverability, something that is difficult to arrange with a large smooth surface. The Delta Clipper design thus used a nose-first re-entry with flat sides on the fuselage and large control flaps to provide the needed cross range capability. Experiments with the control of such a re-entry profile had never been tried, and were a major focus of the project

Your comparison is like comparing an airplane to a car, and complaining the airplane taxiing down a runway is nothing special because cars already travel down roads. The Delta Clippers were a totally different experiment, a totally different craft, with a completely different intended mission. the delta clipper was a SSTO replacement concept for the shuttle. the grasshopper is a reusable launcher replacement for the current dispoable fuel tanks and giant rockets such as Soyuz and Aries.

Re:Did SpaceX take on anybody from Armadillo? (1)

h4rr4r (612664) | about a year ago | (#44573295)

Those were single stage to orbit. That makes no sense.

Grasshopper is about recovering the first stage. A way more sensible goal.

Re:Did SpaceX take on anybody from Armadillo? (1)

Anonymous Coward | about a year ago | (#44574561)

The actual vehicles were tech demonstrators for their takeoff/maneuver/landing capability, and the exact demo they used was to lift off, move sideways, and land again. Seems relevant enough.

Re:Did SpaceX take on anybody from Armadillo? (0)

Anonymous Coward | about a year ago | (#44573983)

DC-Y was never built. After a few flights under SDIO, DC-X was modified to the DC-X1. It was transferred to NASA who left a hydraulic line on the landing gear disconnected and they crashed it on landing after their first flight. (It landed fine, then the gear collapsed and it fell over and caught fire.)

Re:Did SpaceX take on anybody from Armadillo? (1)

Anonymous Coward | about a year ago | (#44573001)

Maybe they just took on someone who knows his differential equations? After all, VTOL is only 'rocket science' if you don't have any actually control engineers on the team ;-)

Re:Did SpaceX take on anybody from Armadillo? (0)

Anonymous Coward | about a year ago | (#44574057)

When I see VTOVL my first thoughts are of Phil Bono, who did extensive work on it in the 1960s (and has some of the key patents), of Gary Hudson, who resurrected Bono's work in the 1980s as Pacific American's Phoenix, and who helped persuade Max Hunter (the guy who designed the Thor, forerunner of the Delta), General Danny Graham, and Jerry Pournelle to in turn convince the Bush (Sr) administration to fund DC-X, which flew a bunch of times before NASA broke it.

Armadillo, admirable as their work was, came after all that. What they did do was help show how easy it could be (given throttleable engines and modern flight control systems).

So not impressed...at all (2, Funny)

mandark1967 (630856) | about a year ago | (#44572485)

The Space shuttle can fly in over a thousand different directions -at the same time- if its heat shield is damaged.

Re:So not impressed...at all (1)

ibwolf (126465) | about a year ago | (#44573933)

I don't know which is worse, the joke itself or that someone actually thought it was funny.

... had to land like a plane? (-1)

Anonymous Coward | about a year ago | (#44572501)

Well, it did land like a 'plane, yes, but it was designed to do so as, presumably, it was deemed the best (cheapest?) way to do it. Saying it had to kinda implies it was just fortuitous that there was a landing strip available the first time it came back!

Astronaut1: Houston, we have a problem. I am unable to find the button for the retro rockets!
Houston: The hell you say, boi! That doesn't sound like a very intelligent design!
Astronaut2: Hey, just seen some little wingy-type things out the window, maybe we can use them?
Houston: Look around and see if there's a button marked something like "landing gear" ...
Astronaut1: Blimey ... yes there is. Just next to the button to switch on the "fasten seat belt" and "no smoking" lights
Astronaut2: Please replace your trays in the seat-back infront of you and return your stewardess to the upright position
[doors to automatic]

I assume that SpaceX are now thinking the extra weight of wings, control surfaces, landing gear, etc, is now greater than the extra weight of fuel required for a rocket-based controlled landing.

I'm of a 'certain age' (0)

Threni (635302) | about a year ago | (#44572503)

Aren't we all?

Re:I'm of a 'certain age' (0)

Anonymous Coward | about a year ago | (#44572535)

Aren't we all?

It's usually used as code to say "I'm old" -- we just don't like to say it that way.

Re:I'm of a 'certain age' (1)

Anonymous Coward | about a year ago | (#44572749)

Whooosshhh

Re:I'm of a 'certain age' (1)

VortexCortex (1117377) | about a year ago | (#44572895)

Aren't we all?

It's usually used as code to say "I'm old" -- we just don't like to say it that way.

Well, actually, "certain age" is used to mean that you know enough that you're certain about everything you say. That the terminology is used by those typically above average age is just a probabilistic occurrence because of the small window of time it's applicable to those of the other age range.

For instance: The teenage girl was at a certain age...

Re:I'm of a 'certain age' (1)

Freshly Exhumed (105597) | about a year ago | (#44575083)

Thanks to George Pal [wikipedia.org] we already know that when a rocketship lands on its tail on another planet a bevy of beautiful space women will attack in their high heels.

Watching the video (2, Insightful)

Anonymous Coward | about a year ago | (#44572533)

Diverts like this are an important part of the trajectory in order to land the rocket precisely back at the launch site after re-entering from space at hypersonic velocity."

While watching the video, I just imagined the "gas" gauge needle sinking fast to 'E'.

Having to carry all the extra fuel to land like that is going to drastically reduce the payload.

That's why space missions usually land some other way - parachute, blow up balls, crash land, etc ... more room for equipment.

Re:Watching the video (5, Informative)

dywolf (2673597) | about a year ago | (#44572739)

Actually the article misses the point. This isnt the reentry vehicle. This is the launcher. The first stage of a multistage vehicle, and it never leaves hte atmosphere. The idea is to create completely reusable launchers and thus lower cost. Now the upper stages could also benefit from this series of experiements and developmental work; this craft is testing multiple things, and a reentry vehicle that simply lands vertically back home has a few advantages (no really big landing field at really high speed like the shuttle, no uncontrolled parachute descent like current capsules).

But the main thrust (pun) of it is reusable launcher stages, with a side benefit of also being able to apply the tech to upper stages and the reentry vehicle as well. So its not a SSTO (single stage to orbit) vehicle like the old DC-X mcdonnel douglas was toying with.

Re:Watching the video (1)

camperdave (969942) | about a year ago | (#44573215)

The fuel isn't extra fuel. The fuel is buffer fuel, as in "We need x tons of fuel to boost the upper stage, so put x+y on board so we don't run out too soon". They're flying back on the y.

Re:Watching the video (1)

BitZtream (692029) | about a year ago | (#44574307)

And then you have to add buffer fuel for the flight back because flying only part of the way back and landing on someones house because you ran out of gas is the exact reason the buffer fuel is there int he first place.

1ST rule of rocket engineering: YOU NEVER FUCKING PLAN TO USE YOUR BUFFERS. YOU PLAN TO NEVER EVER EVER EVER USE YOUR BUFFERS, and then use them only when the alternative is death.

You utterly fail to understand sound engineering practices.

Re:Watching the video (1)

Erich (151) | about a year ago | (#44575385)

Your "1ST rule of Rocket Engineering" can also be stated: You always develop sub-optimal rockets.

Seems like a stupid rule to me.

If an engine goes out, or there is some other problem, you need extra fuel to accomplish the mission (increased gravity drag). So you have some extra fuel and extra delta v, and that's a good thing.

But if those events are rare -- and, eventually, they should be -- then you often have extra fuel. If you can use that fuel to return the craft intact to reuse and make more money, then I think that's a damn good idea. If you must burn the extra fuel, then you will lose the stage. It will cost the company more, but "less profit" is maybe an OK choice.

The goal is to optimize cost while maintaining very high reliability. For very high reliability, you need to understand worst case behavior. For optimizing cost, you need to make the common case cost efficient. Having extra delta v for anomalies and using that delta v to lower launch cost (via reuse) when no problems arise seems like smart engineering to me.

Re:Watching the video (1)

camperdave (969942) | about a year ago | (#44575797)

And then you have to add buffer fuel for the flight back...

Not if what is left over after the boost phase is finished is beyond ample for the task. In other words, Y>R+M, where R is what you need to return, and M is a safety margin.

I disagree with never planning to use your buffers. You have a flight plan for nominal flight. You have a flight plan for engine out. You have a flight plan for two engines out, etc. You plan for every foreseeable contingency, and some of those flight plans will specify using the buffers. Now, for a nominal flight plan, yes, you do not use the buffers.

Once the boost phase is over, any buffer propellant is no longer part of the main mission profile. In other words, once the boost phase is over, the buffer propellant is no longer buffer propellant. It can thus be used as fly-back and landing propellant.

Delta clipper? (0)

Anonymous Coward | about a year ago | (#44572539)

rockets going sideways is not that new [youtube.com]

Impossible my ass! (-1, Troll)

Shavano (2541114) | about a year ago | (#44572541)

I've got video of Niel Armstrong landing a vertical landing and take off rocket on the moon in 1969. Glad to see Space X could catch up.

There's only one reason why normal rockets don't land tail-down: it's INEFFICIENT when you have an atmosphere to work with. The space shuttle and NASA and Russian landing capsules land using no fuel. Beat that, Space X.

Re:Impossible my ass! (1)

SJHillman (1966756) | about a year ago | (#44572565)

The moon has considerably less gravity and atmosphere to worry about for VTOL. So if it's practical on the moon in 1969, it's reasonable it would take the better part of a century to become practical on Earth given that rocket technology hasn't changed that drastically since the Nazis were launching V-2s (or depending on how you define drastically, since the Chinese were launching emperors, see Wan Hu).

Re:Impossible my ass! (1)

Shavano (2541114) | about a year ago | (#44572665)

Is he the Wan Hu was legendarily blew himself up with rockets?

Re:Impossible my ass! (1)

BitZtream (692029) | about a year ago | (#44574347)

The moon has considerably less gravity and atmosphere to worry about for VTOL. So if it's practical on the moon in 1969, it's reasonable it would take the better part of a century to become practical on Earth

Ok, look at the videos of the tests of the moon landers and systems here on earth ... under our own gravity.

You are correct that rocket tech really hasn't changed, yet somehow you think today we can do it but back then we couldn't?

Your post is utterly conflicted.

Re:Impossible my ass! (1)

SJHillman (1966756) | about a year ago | (#44575333)

My post makes a few points, but I don't see the conflict.
1) Rocket tech hasn't changed much. This, we agreed on.
2) It was practical to do it that way on the moon in 1969.
3) It has not been practical to do it on Earth up to this point.
4) The main difference in practicality between Earth and the moon has to do with atmosphere (or lack thereof) and gravity.

Don't confuse practical with possible. I never said we couldn't do it on Earth, just that we've had better ways due to the slow evolution of rocket technology and that might finally be changing.

Re:Impossible my ass! (0)

Rakshasa-sensei (533725) | about a year ago | (#44572595)

Hi, my name is Shavano and I know not what I speak of.

Re:Impossible my ass! (5, Insightful)

dywolf (2673597) | about a year ago | (#44572693)

bad comparison. the LM actually operated in reverse. it landed at a site, then took off. that is very different from taking off and then landing back at that exact same site. furthermore, the part that took off was a totally seperate piece with its own rocket engine, so technically it was two craft (or two stages) performing two seperate operations, not one craft performing both. the grasshopper is also far far larger than the LM, and exercising greater degree of control and precision in a heaver gravity and different atmosphere.

and while you alude to the crew capsules landing without fuel, the current crop of LAUNCHERS in use, are disposable single use entities, which means you apparently missed the entire point of this experimental rocket is to validate the concept of a reusable launcher, which would dramatically reduce costs.

short version: shutup

Don't forget... (0)

Anonymous Coward | about a year ago | (#44572905)

The part that landed the LM was left on the moon.

Re:Impossible my ass! (0)

Anonymous Coward | about a year ago | (#44575407)

The space shuttle and NASA and Russian landing capsules land using no fuel. Beat that, Space X.

None of those have recoverable first stages; the shuttle might have been much cheaper to fly if the booster rockets were reusabe. Did you not even read the fucking SUMMARY??

I love Elon Must and Space X (0)

Anonymous Coward | about a year ago | (#44572543)

But the stuff he is doing has been done before and doesn't actually answer a lot of the questions required for re-usability.

http://www.youtube.com/watch?v=JzXcTFfV3Ls

That's the DCXA and is a SSTO (Single Stage To Orbit).

Here is the BIG questions:

1) How big will it need to be to carry enough fuel to push something to NEO and come back.
2) How do you de-couple upper stages from it? You're going to be constantly burning, You'll need to turn off the rocket, or fire retro-grade rockets to slow it down so that the upper stages can de-couple.
3) Where do you launch/land from? You either need a huge area to cover (Calif to FL) or Lots of fuel to make the return trip.

Re:I love Elon Must and Space X (0)

Anonymous Coward | about a year ago | (#44572623)

His name is Elon Musk. With a 'k'. Not "Must".

There's a big difference.

(think of the difference between something that smells musty [merriam-webster.com] and something that smells musky [reference.com] ....)

Re:I love Elon Must and Space X (2)

taiwanjohn (103839) | about a year ago | (#44572909)

Trouble is, the DCX never made it to orbit (not even close) whereas the Falcon 9 has.

This is a modification to the existing F9 platform. IIRC, they expect it to reduce the payload capacity by about 25~30%. And yes, they intend to salvage the upper stage too. [youtube.com] If they can do that, they'll reduce costs to a few million$ per launch. (About $250k in fuel; skirt/solar module for the Dragon; launchpad services, etc..)

They generally launch from Cape Canaveral, though they are trying to get the legislature to approve a launch site in Texas too.

When I was a kid (-1)

Anonymous Coward | about a year ago | (#44572553)

I watched He--Man as a kid... from there I learned the basics of physics and other important stuff. Now I have three kids (each with different mother, and haven't seen any of them in years), and live in a cardboard box in iceland.

When ever I steal a phone, I use it to browse /. and post stupid comments, untill the owner shuts down his service or finds me with the various "Find your phone" systems... This usually leads to me getting beat up.

Other than that, I'm doing O.K. :)

Editing lessons (0, Offtopic)

wonkey_monkey (2592601) | about a year ago | (#44572601)

They always showed rocket ships sitting on their tails and blasting off, and landing, straight up[1]. The shuttle went up that way but had to land like a plane[2], and anything else[3] was considered impossible or impractical. Now, the Space X's rocket Grasshopper can not only do that

Do what?

thought it was about insects (1)

shadowrat (1069614) | about a year ago | (#44572685)

Am i the only one who wondered when the summary was going to get to something relevant to entomology? I was really baffled. I didn't know what rockets had to do with bugs :/

thought it was about kung-fu (2)

VortexCortex (1117377) | about a year ago | (#44573079)

Am i the only one who wondered when the summary was going to get to something relevant to entomology? I was really baffled. I didn't know what rockets had to do with bugs :/

Am i the only one who wondered when parent poster was going to get to something relevant to walking trees? I was really baffled. I didn't know what Ents had to do with bugs.

Am i the only one who wondered when the quoted text was going to get to something relevant to recursion? I was really baffled. I didn't know walking a tree had nothing to do with bugs.

Am i the only one who wondered why the quotes were forming some strange iterative behavior? I was really baffled. I didn't know why the stack trace was missing several parent posters; Probably -O dead code elimination, self referential side effect, or a GOTO bug.

I post therefore I was.

So, um (0)

Anonymous Coward | about a year ago | (#44572743)

stuff that's been done decades ago? I don't have a clue as to why rocketing up the fuel you need to hover back down is supposed to be good, though.

Re:So, um (1)

camperdave (969942) | about a year ago | (#44573245)

Ten thousand dollars of extra fuel saves you 30 million dollars of rocket parts. Seems dead simple to me.

Re:So, um (0)

Anonymous Coward | about a year ago | (#44575743)

Ten thousand dollars of extra fuel saves you 30 million dollars of rocket parts. Seems dead simple to me.

But how many less million in payload capacity?

Big deal... (0)

Anonymous Coward | about a year ago | (#44572867)

it's not like it's rocket science...

Iron Man (0)

tverbeek (457094) | about a year ago | (#44572933)

Tony Stark has been doing this for 50 years.

Re:Iron Man (-1)

Anonymous Coward | about a year ago | (#44573093)

you are lame, go away..

Re:Iron Man (1)

crakbone (860662) | about a year ago | (#44573461)

Didn't you know Elon Musk is Tony Stark.

"Elon Musk" is a Bond villain name (0)

Anonymous Coward | about a year ago | (#44574709)

Re:Iron Man (0)

Anonymous Coward | about a year ago | (#44574851)

Also, Powdered Toast Man has been flying backwards for 20 years.

Lockheed (1)

The Grim Reefer (1162755) | about a year ago | (#44573185)

I always found this video [youtube.com] to be impressive. It's a little scary in a terminator sort of way too.

Thrust vector control (5, Informative)

Medievalist (16032) | about a year ago | (#44573391)

We used to call it "thrust vector control". I worked in the Morton-Thiokol TVC lab for a while. The video shows a really excellent example of the technique, which is not new or controversial.

You can do TVC with hydraulics (heavy, but parts are easy to source and last longer) but you'll get better impulse numbers [wikipedia.org] for the vehicle as a whole if you can divert some proportion of the pressure from the combustion chamber into mechanical actuators that change the direction the nozzles are physically pointing. With multi-nozzled rocket motors (regardless of whether they have multiple combustion chambers or not) you can point some thrust down and some to the side (which appears to be happening in the video) and get this kind of behavior.

Similar things can be done with moving vanes in the exhaust plume, but those will erode even faster than the mechanism described above, and will be far slower to change the thrust vector. Erosion of parts that have high pressure hot gasses flowing through them is a huge issue in rocketry, although fairly well understood at this point. External aerodynamic vanes like the space shuttle's wings will obviously work too, and won't erode much (during liftoff) but they are also slow and clumsy.

When I say the technique's not new, I do not mean to denigrate the achievement. I can confidently state that it's really, really hard to do it as well as is being shown in this video. I would love to be able to work with these guys, because they are clearly just full of the right stuff.

Another alternative system to TVC is separately fueled ACMs - Attitude Control Motors - such as vernier thrusters [wikipedia.org] or the solid fuel ACMs on hypersonic crusie missiles. When you use gimballed nozzles to achieve TVC, though, you can potentially have the entire force of the main thrusters available for attitude control, and the fuel delivery system can be much more concentrated and simple.

Graphical overview of the common methods of TVC here [nasa.gov]

Re:Thrust vector control (2)

adamgundy (836997) | about a year ago | (#44575027)

there is only a single nozzle on the grasshopper - one merlin 1D engine. the second, angled off to the side, jet of flame that you see is the low pressure exhaust from the gas generator on that engine, which has then ignited on contact with the oxygen in the air, since it runs fuel rich.

it provides very little in the way of thrust, and is not controllable on the 1D. on the merlin 1C vacuum version, it was directed and used for roll control - it appears that the merlin 1D-VAC directs the turbopump exhaust into the main engine bell to improve ISP, so presumably they plan on using cold gas or draco thrusters for upper stage roll control now.

you're correct that merlin 1D (and all the previous merlin models) use high pressure fuel from the output of the turbopump as the hydraulic fluid for gimbaling the engines - which has the nice advantage of not being able to run out of hydraulic fluid (or at least: you only run out when the engine quits firing).

Not the insect? (1)

dmmiller2k (414630) | about a year ago | (#44573673)

Am I the only one who clicked through to this while scanning headlines, thinking it referred to living creatures?

Lunar Lander (0)

Anonymous Coward | about a year ago | (#44573679)

I was doing this in arcades in the 80's.

DC-X (0)

Anonymous Coward | about a year ago | (#44573925)

The Delta Clipper (Experimental) did this about twenty years ago.

It is pretty awsome watching a rocket lift off, stop dead a few hundred feet up, move sideways a few hundred feet, and then descend to a landing. But it has been done.

That said, kudos to Space X for doing it with their own vehicle.

-- Alastair

Waste of fuel! (0)

cyn1c77 (928549) | about a year ago | (#44573977)

The controlled burn decent shown in the video looks impressive but will always be impractical from a financial perspective.

In fact, it is the most horrific way to land a rocket coming from space due to the amount of fuel that would need to be used to decelerate it. We use parachutes or wings to slow things down for landing in an atmospheric environment because it saves a lot of energy compared to doing a direct burn for deceleration.

Essentially, you have to use at least as much fuel as you needed to get the return payload up in the first place. Then remember that you need to also use extra fuel on the ascent to lift all that extra fuel that you need for the descent! Compare this to a heat-shield/parachute re-entry where you use almost no fuel.

Thus, this technique will only be useful for landing in places with no atmosphere or as a final descent stage after using some other method to slow the rocket down from the hypersonic re-entry velocity. Also remember that the Eagle lunar landing module did everything shown in that youtube video back in 1969.

Re:Waste of fuel! (1)

BitZtream (692029) | about a year ago | (#44574447)

The is a first stage. There is no re-entry. It pretty much goes up and falls back down. Historically we'd let it fall in the ocean, then maybe salvage parts of it.

This lets it fall back down ... in a controlled manner, to where it started from, with little to no damage.

That changes the equations a little

YOU THINK I MAEK JOKE: (1)

Thud457 (234763) | about a year ago | (#44574881)

Well, it's certainly cheaper than having some internet billionaire salvage your rocket parts off the sea floor [space.com] for you.

Of course with precedents like Howard Hughes, the Glomar Explorer and project Jennifer [wikipedia.org] and Robert Ballard finding the Titanic while secretly researching the Scorpion & Thresher wrecks [nationalgeographic.com] , it leads one to wonder what internet billionaire Jeff Bezos is really up to.

Re:Waste of fuel! (1)

TheSync (5291) | about a year ago | (#44575169)

Soyuz uses parachutes to fall at 7.2m/s. Then about a 0.5s before landing, six solid-fueld soft landing engines fire to slow the vehicleâ(TM)s descent rate to 1.5 m/s just 0.8m above the ground.

Huh, man-made I guess (0)

Anonymous Coward | about a year ago | (#44574741)

I came here expecting to see some new discovery about insects.

Shut up, Winky (0)

Anonymous Coward | about a year ago | (#44574779)

Rocky Jones. Gimme a break.

Was expecting an actual insect (1)

istartedi (132515) | about a year ago | (#44575285)

Is anybody else disappointed that TFA doesn't have slow-motion video of an actual grasshopper (the insect) flying sideways? That'd be pretty cool.

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