Preliminary Analysis of the 6 April 98 Pakistani Ghauri Missile Test

Preliminary Analysis of the 6 April 98 Pakistani Ghauri Missile Test

April 10, 1998
David Wright
Union of Concerned Scientists and
Security Studies Program, MIT

I have conducted a preliminary analysis of the information available in the press about the reported Ghauri missile test. This is based in part on my past analysis of the North Korean Nodong missile.

Some reports have stated that the missile appears similar to the Nodong.

From the photos of the launch that were released by Pakistani television, one can get a very rough estimate of the size of the missile based on the trucks in the background. From this, the missile appears to be very roughly the same size as, though possibly smaller than, the Nodong, which is reported to be 15.2 meters long and 1.2 meters in diameter. (The photo is at http://www.jang-group.com/thenews/apr98-daily/07-04-98/frmain.htm)

Several reports have given the total mass of the Gharui missile as 16 tonnes (te) and the payload as 700 kg. Fuel masses of both 13 and 14 tonnes have been reported. A fuel mass of 14 tonnes would give a fuel fraction for the booster of 91.5%, which appears unrealistically high without access to very lightweight materials. A fuel mass of 13 tonnes would give a fuel fraction of 85%, which is a reasonable value assuming the missile body is made of aluminum, rather than steel (which Scuds are made of). Thus a total mass of 16 tonnes and a fuel mass of 13 tonnes appears to be self-consistent.

In comparison, my analysis of the Nodong gives estimates of the mass that are a couple of tonnes larger than these figures (about 18.5 tonnes total mass and 15 tonnes of fuel). Thus, if the reported figures for the Ghauri are correct, the missile appears to be the same general size but somewhat smaller than a Nodong.

(One report stated that the Ghauri had three stages. This appears to be a misinterpretation of Pakistani reports that "the missile will formally be tested in three stages.")

A Test to a Range of 1,100 Kilometers?

Press reports about the Ghauri have typically mentioned a range of 1,500 km for the missile, but the range of the test is usually given as 1,100 km with a flight time of 9 minutes and 58 seconds. Many reports mention that the missile rose to an altitude of 350 km. This appears to refer to the apogee, or highest point of the trajectory, which occurs in the middle of the trajectory.

My calculations show that a missile powered by four Scud engines (which is the Nodong configuration) and having a mass of 16 tonnes and carried 13 tonnes of fuel would have a maximum range of about 1,100 km with a 700 kg payload. (This assumes a sea-level specific impulse of 222 seconds, which is the value for Scud B engines fueled by kerosene and nitric acid.) The standard trajectory for this range would give an apogee of about 300 km and a flight time of about 9.6 minutes. However, if this missile was flown on a slightly lofted trajectory, it could still reach 1,100 km range but with an apogee of 350 km and a flight time of just over 10 minutes, which would agree with the press reports. Thus, the press reports might be consistent with a Nodong-like missile.

It is interesting to note that if the payload of such a missile were reduced from 700 kg to 200 kg, the range would increase to roughly 1,500 km.

A Test to a Range of 700 Kilometers?

It is possible, however, that the range of the test was considerably shorter. Several press reports state that the launch took place in northern Paksitan near the city of Jhelum and that impact occurred near the city of Quetta. From a map it is easy to verify that these cities are only about 700 km apart. (One source within Pakistan said that he had heard that impact occurred on the southern coast of Baluchistan. If true, this would allow enough space for a 1,100 km flight test if launched from Jhelum.)

If the flight test was 700 km rather than 1,100 km, this suggests a different explanation. In mid-1997, Pakistan claimed to be developing an 800 km Hatf 3 missile. An 800 km range missile on a normal trajectory would have an apogee of about 200 km and a flight time of 8 minutes. However, if the missile trajectory was lofted slightly to give an apogee of 350 km, my calculations show that the missile would then have a range of about 700 km and a flight time of ten minutes.

It is also interesting to note that if the payload on this missile were reduced from 700 kg to 200 kg, the range would increase to about 1,100 km.

Without knowing more details, there are several possibilities that need to be considered:

(1) One possibility is that missile masses given in the press reports are wrong but the test range of 1,100 km is correct, and the Ghauri is a Nodong missile that was sold to Pakistan by North Korea. There are reports of contacts between Pakistan and North Korea concerning missiles over the past five years, and this may have been the result of those contacts. If the US and other countries believe this is the case, it is difficult to understand the muted international reaction to the launch. Evidence of a foreign Nodong sale would be of especially great concern to Israel.

(2) A second possibility is that the Ghauri is largely indigenous, but is a design similar to the Nodong. The Nodong is believed to achieve its range by clustering four Scud engines. For simple liquid-fueled engines of this type, clustering is an obvious step to increase missile range and should not be a difficult thing to do. If Pakistan has working short-range, Scud-type liquid-fueled engines that it has either developed or purchased, it seems plausible that it could build a longer-range missile by clustering engines. Ground tests of a missile engine were reported in Pakistan last year, which may have been an engine it used in the Ghauri. Pakistan may have received technical assistance or even some hardware from abroad (North Korea or elsewhere), which it may then have used to build such a missile.

The point here is that even if the missile is in fact similar to a Nodong, it does not necessarily mean that North Korea transferred a Nodong missile to Pakistan. It is worth noting that since Pakistan's earlier experience in missile design was with solid-fuel engines, if the Ghauri is liquid-fueled it would suggest some level of assistance from abroad.

(3) A third possibility is that Pakistan has a missile with an 800 km range and that the test was only 700 km. This would be consistent with Pakistani claims last year that it had an 800 km Hatf 3, although apparently no test of a missile to that range has been observed. As mentioned above, ground tests of an engine being developed were reported last year, and were believed to be for Hatf 3 missile.

(4) A fourth possibility is that the missile is completely different from the Nodong. Some reports have raised the possibility that China transferred a missile or assisted Pakistan in building a missile of its own. The missile in the television photo does not look like a Chinese M-9 missile (600 km range).

(5) A final possibility that has been raised is that the launch shown on television was of a much shorter-range missile, and that Pakistan is exaggerating its missile capability for political purposes. Estimating the size of the missile from the television photo seems to give dimensions that are too large for a Scud B or M-11, but the estimate is so rough that it is not possible to rule out this possibility entirely.