Iran Sends First Satellite into Orbit

[bart]

Re: Iran Sends First Satellite into Orbit

Bart, I have the utmost respect for your knowledge in the financial and economic realm, but physics doesn't work that way. Hitting a spot on earth that is 150 miles laterally from the launch site is a different proposition from lifting the same mass 150 miles vertically. Also, getting to orbit isn't the same thing as displacing the satellite by 150 miles vertically.

Fair enough and I'm far from expert in the area and you actually may literally be a rocket scientist, but I still urge caution on it meaning that they have intercontinental capability, reliably or not.

[ASH]

Re: Iran Sends First Satellite into Orbit

Fair enough and I'm far from expert in the area and you actually may literally be a rocket scientist, but I still urge caution on it meaning that they have intercontinental capability, reliably or not.

The connection between orbit and missile range is that if you can make a mass circle the earth, then you can by definition put a mass anywhere on earth by using slightly less juice. Of course, there are caveats: it is easiest to put something in orbit by launching eastward from the equator, because of the ~1000 MPH assist from the earth's rotation. So, technically, the ability to put a satellite into an equitorial orbit doesn't mean that you can hit a polar orbit, but you'd be pretty close. In any event, an ICBM only has to travel to the opposite side of the earth -- it doesn't have to circle the earth or stay in orbit. Hence, the ability to orbit a satellite has traditionally been associated with ICBM capability in the history of military rocketry, because it means you have a launch vehicle that is over-kill for hitting a target on the far side of the planet.

The limited range of existing Iranian ballistic missiles is part of the reason I am skeptical of their claims to have put a satellite in orbit. It is much easier to do a sub-orbital flight that temporarily passes into space.

For reference, to stay in a circular orbit 150 miles above the surface of the earth, a satellite would have to travel at about 17,370 MPH. Ignoring air resistance and the curvature of the earth, the initial velocity required to coast 150 miles laterally on a maximally efficient trajectory is only about 2,430 MPH. That gives you some idea of the difference in performance required of a short-range ballistic missile and an ICBM.

[bart]

Re: Iran Sends First Satellite into Orbit

The limited range of existing Iranian ballistic missiles is part of the reason I am skeptical of their claims to have put a satellite in orbit. It is much easier to do a sub-orbital flight that temporarily passes into space.

Cool.

And one of the many things we also don't know is how much help, one time or not, they got from Putin & Co.

[ASH]

Re: Iran Sends First Satellite into Orbit

And one of the many things we also don't know is how much help, one time or not, they got from Putin & Co.

The axis-of-folks-who-want-the-US-to-butt-out makes for some strange bedfellows.

[bart]

Re: Iran Sends First Satellite into Orbit

The axis-of-folks-who-want-the-US-to-butt-out makes for some strange bedfellows.

Indeed, and way more "interesting" times than most would prefer.

[c1ue]

Re: Iran Sends First Satellite into Orbit

I think inertial measurement is probably the more fundamental guidance technology for ballistic missiles. Probably laser gyroscopes. It's not just position, but also attitude.

I agree that satellite navigation could be used in combination with an IMU (inertial measurement unit), but why bother launching their own satellite constellation when there's already GPS to piggy-back on?

GPS is fine for hitting a city, not so useful for targeting potentially moving targets.

Also Iran doesn't have ballistic missiles, it has the more prosaic type.

How much modification is necessary to convert missiles intended to hit ships and planes to target on other objects or targets? ;)

[ASH]

Re: Iran Sends First Satellite into Orbit

GPS is fine for hitting a city, not so useful for targeting potentially moving targets.

Also Iran doesn't have ballistic missiles, it has the more prosaic type.

How much modification is necessary to convert missiles intended to hit ships and planes to target on other objects or targets? ;)

This is just a semantic argument, but I can't resist being pedantic in a field that is adjacent to my profession. (This is a character flaw.)

"Ballistic missiles" include short-range weapons. To qualify as ballistic, a missile must follow a ballistic trajectory, or as Merriam-Webster has it, "a missile guided in the ascent of a high-arch trajectory and freely falling in the descent." The essence of this is that the missile's rocket motor burns out on the way up, and the warhead coasts to its eventual target, rather than traveling in powered flight.

The Federation of American Scientists has a convenient list of Iranian ballistic missiles. Included are:

250 - 300 single-stage short-range ballistic missiles based on the Scud-B design (domestically called Shahab-1), with a range of about 330 km (205 miles)

200 - 450 single-stage short-range ballistic missiles based on the Scud-C design (domestically called Shahab-2), with a range of about 700 km (435 miles)

Iran also has various 2- and 3-stage medium- and intercontinental ballistic missiles under development, including their supposed space launch vehicle.

Anyway, regarding modification of anti -ship or -air missiles, I'd have to say it depends upon what it is you're trying to hit. Most of those types of guided missiles use either radar or infrared, so whatever it is you are trying to hit better have a distinct signature for the sensor in question. Also, you'd obviously have to work within the range limitations of the missiles, and you might need to consider whether the warhead was appropriate. It's one thing to shread the control surfaces of an aircraft with shrapnel (e.g. 40 kg explosive charge in an AIM-7 Sparrow missile) versus punching through the hull of a ship (e.g. 221 kg explosive charge in an AGM-84 Harpoon missile). I wouldn't expect modification to be very easy in most cases, as I expect the guidance systems are tuned for a very specific type of target, and probably aren't implemented in a flexible way.

[lakedaemonian]

Re: Iran Sends First Satellite into Orbit

Cool.

And one of the many things we also don't know is how much help, one time or not, they got from Putin & Co.

And North Korean No Dong missile tech.

I am also highly skeptical of Iranian orbital achievement claims.

In light of recent events in nuke armed Pakistan combined with open German claims of very recent Pakistani complicity in A'san insurgency......Iran is almost a non-event for the moment.

[c1ue]

Re: Iran Sends First Satellite into Orbit

There are both cruise missiles and the 'ballistic' type.

Sure, the Silkworm only has a range of 95 km, but it has a warhead of 513kg. More than enough payload to be useful eh?

The Noor has a significantly smaller warhead, but can be fired from a chopper and has a 200 km range.

So at present Iran can't hit Israel with something modified from an anti-ship and must use the crappy SCUDs, but then again there is such a thing as planning for the future.

Note that an ICBM ballistic is completely different than a in-atmosphere ballistic.