NASA has three smartphones orbiting the earth as mini-satellites

Re:NASA has three smartphones orbiting the earth as mini-sat... by ck2 on Friday April 26, 2013 @11:23AM (#5613397)

The launch was kinda neat too:

http://www.youtube.com/watch?v=V3L7crGudVU

Finless rocket? How does it steer/stabilize? Do the engines have fine control over which side their fire perhaps?

I guess fins are useless outside of atmosphere anyway.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by dexen on Friday April 26, 2013 @11:59AM (#5613614)

Probably steered through thrust vectoring. Liquid fuel rocket engines are often built to gimbal, typically 1...2 degrees to each side. http://en.wikipedia.org/wiki/Rocket_engine#Thrust_vectoring

Another possible method of steering is to build four or more reaction jets around the rocket; could be fed with a monopropellant or exhaust from the main engine or its turbopump.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by gngeal on Friday April 26, 2013 @05:02PM (#5615466)

If you can deal with slight decreases in thrust, you can also do thrust vectoring with injecting water or other suitable liquid into the nozzle in proper places. Could be mechanically simpler than gimbals in some cases.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by bitwize on Friday April 26, 2013 @02:08PM (#5614457)

Thrust vectoring owns the sky! Now you've got me thinking of cellphones turning on a dime, Macross Zero style.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by blhack on Friday April 26, 2013 @12:52PM (#5613926)

One of my friends is on the team that built this: thrust vectoring.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by InclinedPlane on Friday April 26, 2013 @04:52PM (#5615405)

I don't know that I'd describe the launch as "neat". I'm searching for the right word to describe it... I guess maybe.... "nominal".

Anyway, almost all modern rockets don't use fins. They steer using thrust vectoring and attitude control thrusters.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by gngeal on Friday April 26, 2013 @05:06PM (#5615490)

Anyway, almost all modern rockets don't use fins.

...they don't start working until you're fast enough (quite high above the ramp, which is a sensitive area where you really need it) and they stop working once you leave the atmosphere (which is all too soon for an orbital carrier). Why bother with them?

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Re:NASA has three smartphones orbiting the earth as mini-sat... by Retric on Friday April 26, 2013 @05:19PM (#5615580)

There generally on the bottom stage so they don't reach Anything close to orbit. But what there really useful for is dampening rotations which is hard to fix with a thrust vectoring system.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by pjkundert on Friday April 26, 2013 @06:08PM (#5615784)

Only on single engine stages; with 2 or more engines, damping rotation is no problem.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by twistedpair on Friday April 26, 2013 @01:55PM (#5614370)

This has been being done for a long time. Saturn V's were thrust vectored too. For any large scale rocked, the fins are far to large to move like on smaller missiles.

This works well to cut down on mass and drag and is especially useful for silo/sub launched missiles where fins don't fit well in the launch tube.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by tiredofcareer on Friday April 26, 2013 @03:12PM (#5614847)

Before someone corrects you with a photograph, the ascent stage had fins in addition to the vectoring on the F-1s. However, my understanding, though I might be wrong, is that those were intended for stabilizing the vehicle instead of acting as control surfaces.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by trafficlight on Friday April 26, 2013 @12:11PM (#5613669)

I assume the engines are gimbal mounted and can direct their thrust.

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Re:NASA has three smartphones orbiting the earth as mini-sat... by civilian on Saturday April 27, 2013 @03:35PM (#5618801)

You need to play more Kerbal Space Program http://kerbalspaceprogram.com/

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Re:NASA has three smartphones orbiting the earth as mini-sat... by maaku on Friday April 26, 2013 @02:40PM (#5614650)

When was the last time you saw a rocket with fins?

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