North Korea launched a rocket carrying a satellite into space on Sunday - yet, it is not Pyongyang's extraterrestrial ambitions that have countries around the world worried.

Instead, central to international concerns is whether North Korea's rocket technology could potentially be used to also deliver a nuclear weapon.

Al Jazeera technology editor Tarek Bazley spoke with aerospace engineer John Schilling to discuss the launch and whether the rocket could be turned into a ballistic missile.

Al Jazeera: What do we know about Sunday's launch of the Unha-3 rocket?

John Schilling: It appeared to be very similar to the rocket they successfully launched in 2012 so apparently they are not trying to launch a new larger rocket like we had suspected.


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The rocket is certainly capable of launching satellites, because it has done so, but it is also capable of launching a warhead, if that is what they are interested in.

Some of the design features suggest that it was optimised for satellite launch rather than missile work. But obviously anything that is capable of doing both missions is a concern to us

Al Jazeera: Could this rocket be turned into an ballistic missile easily and quickly?

Schilling: So far North Korea has launched satellites that go up into space and will eventually come down, but in an uncontrolled fashion and probably break up.

To come down from the atmosphere from outer space at 28,000kmph and not disintegrate is technically challenging. They would need a re-entry vehicle with extensive heat-shielding given the speed.

They would also have to worry about the stability of it. There are text books that will tell you how to do it and if the North Koreans are comfortable with book learning and with robust safety margins they could probably build something fairly quickly.

Al Jazeera: How optimal is the Unha-3 as a ballistic missile?

Schilling: It's very large and cumbersome. We've seen this rocket in preparation for days and even if they streamline that process to hours ,you wouldn't want to use that in a wartime.

It's dependent on a fixed launch site in a country as small as North Korea - and that is another risk for them. We've seen them parading and we think they are trying to develop a smaller mobile missile, the KN-08.


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It's less than half the size of the Unha-3 and would carry a small nuclear warhead to the US West Coast but it could not reach Washington DC or other East Coast targets.

This would be more useful for them but with no testing so far and a new design, we are thinking that's not going to be operational until after 2020.

Al Jazeera: Does the successful launch of the Unha-3 make North Korea more or less of a threat?

Schilling: If North Korea were truly desperate they could probably build some sort of missile this year, but it would be very cumbersome, inaccurate and we'd see it on the pad before it was launched.

Just the fact they launched anything so soon after a nuclear test is seen provocative and probably a violation of UN resolutions but the technical capability doesn't seem to be a great advance on what they demonstrated in 2012.

[The rocket technology] is obviously more reliable because they have two successful launches under their belt and it seems to have been more accurate.

The last time they missed their intended orbit by about 25km and this time they were off by 15km so they are getting better but in small steps.

Source: Al Jazeera