Pakistan’s Quest for Ballistic Missile Capability: An analysis of the Shaheen-III MRBM   

Pakistan’s bid to posture its surface-to-surface missile (SSM) programs as a counter to India’s conventional superiority has been marked by recurrent challenges. The developmental process of the Shaheen III Medium Range Ballistic Missile (MRBM) has been no exception to this. Be that as it may, this article is an assessment of the Shaheen III, based on a close observation of tests conducted through 2015 to 2021.

Background

Although ballistic missile development in Pakistan has been progressed through acquired technology, it has nonetheless met with multiple  problems over the years. Programmes have often found themselves mired in technical difficulties, requiring the import of foreign expertise for mitigation purposes, with China being the principal source for the same. China is of course an old partner for such endeavours with a direct agreement for cooperation in defence science and technology between Islamabad and Beijing being in place since 1989^[1]. Indeed, it would be no stretch to say that this agreement has been a key instigator behind the proliferation of missile technology in the region. Research has also revealed various instances of clandestine and covert transfers of missile-related technology and material from North Korea and China to Pakistan. Despite pressure from the US, China actually deviated from MTCR restrictions in its missile technology relationship with Pakistan^[2].  By all accounts, Chinese and North Korean support has been critical to Pakistan’s multi-decade efforts ^[3] to gain the domestic capability to build and manufacture missiles for its tactical and strategic interests.

Pakistan’s missile technology procurement journey began with the M11 (Ghaznavi) short-range BM (SRBM) during the period 1987~1989^[4]. These were a direct assembly of Chinese M11 missiles^[5]. An estimated 30 to 80 unassembled M11 SRBMs were delivered to Pakistan by China, which were named as Ghaznavi by Pakistan. These were single stage solid-fuelled systems with an effective range of 300 km. The 1990s saw a bolder Pakistan procuring ballistic missile technology from China & North Korea, such as the Ghauri MRBM which was based on the Nodong-1 from North Korea.^[6]

By the end of 1995, it became evident that China had also supplied Pakistan with the longer-ranged M9/DF-15 missiles, which later were internalized and designated as the Shaheen I missile systems, (the precursor to the Shaheen-II and III series of missiles. The missile had thermal protection material made of polymer matrix composite.^[7] Lessons learnt from the ‘development’ of this missile laid the foundation stone for subsequent longer-ranged variants of the Shaheen missile family.

All missiles in the Shaheen family of systems use solid propellants. The number of stages varies with the version of the missile. The Shaheen-I was tested in 2003 and had a range of 750 kilometers with a payload capacity of up to a ton. The next version, the Shaheen II MRBM with a range of 2000 km was tested in 2004. This is suspected to be a variant of the Chinese M18/DF-21 family. The fin stabilizers on the Shaheen-II’s RV (otherwise observed on DF-21 RVs) were removed due to the possible addition of a post separation altitude correction system (PSAC) ^[8] that keeps the missile in proper altitude trajectory during the flight. The same modification was done on the Shaheen-IA. The next missile in the Shaheen ensemble was the Shaheen III with a maximum claimed range of 2750 km and a payload of 1 ton. It is argued in this article that the Shaheen-III has three rocket stages and this is what allows it to reach the claimed range. All Shaheen missiles are nuclear capable as seen in (Table 2)^[9] and their range coverage is depicted in Figure 1.

The Shaheen III

As stated above, the latest in the Shaheen series is Shaheen-III which is currently Pakistan’s longest ranged BM having been tested to a maximum range of 2750 km in 2015. The increase in range of the Shaheen-II from 2000 km to the 2750 km exhibited by the Shaheen-III has been achieved through the incorporation of a 3^rd rocket stage into the system. As such, the Shaheen-III missile system can reach all locations in mainland India barring some island regions (See Figure 1 below)

Figure 1: Claimed Range depiction of Shaheen series of Missiles

Figure 2: Shaheen III Missile

Table 1: Details of Shaheen III tests and range

On 20 January 2021, Pakistan’s Inter Services Public Relations (ISPR) released a press statement stating that a successful test of Shaheen-III aimed at “revalidating various design & tech parameters of the weapon system” was conducted. Incidentally, the last test of the same missile prior to this had been conducted in 2018 and according to an assessment published in Delhi Defence Review was a failed test^[10]. This three-year gap in testing is suggestive of a re-design effort to mitigate problems with the Shaheen-III. Indeed, as the latter half of this article show there were visible changes in the 2021 Shaheen-III test-vehicle as compared to the one used in 2018.

Table 2. Shaheen Missile Series and Characteristics.

Approach Methodology

The International Strategic & Security Studies Programme (ISSSP) at the National Institute of Advanced Studies (NIAS), Bengaluru, has developed methods for assessing the performance of ballistic missiles. These use measurements that are derived from images of the missile along with domain expertise and publicly available information. These methods are then used to estimate basic parameters to compute missile performance. These parameters are further provided as inputs to a trajectory software package developed by NIAS called ‘Quo Vadis’. Quo Vadis computes the trajectory of a missile based on given input vehicle parameters and is able to –

1. Determine the Maximum Range
2. Determine whether it can reach a target for the given parameters
3. Determine whether it can Perform terminal maneuvers

The model includes in its  framework  the earth’s rotation as well as specific impulse variations with altitude. The results for specific cases have been validated against well established ones with agreement better than 2 per cent. The results are in the form of plots-typically parameter vs parameter or time vs parameter plots (usually Range vs Time). The plot representations on  maps and Google Earth for visualization purposes include Latitude vs. Longitude vs. Altitude. Besides, vehicle parameters and launch coordinates. Inputs captured at the GUI include thes no. of stages, inert mass, propellant mass, payload, burn time etc. User has to specify launch coordinates and the target coordinates can be either chosen or the simulated missile can simply fly to the maximum range for the given parameters. The simulated missile can be chosen to fly either a depressed or lofted trajectory. The input and result files are stored in the form of country, missile and variant in an easily retrievable manner.

It appears that Shaheen-III employs a lower stage of Shaheen-II (with perhaps minor changes). For the increased range it incorporates a third stage as mentioned earlier (See Fig.3).

The dimensions of the Shaheen-III were measured through image calibration techniques. The size of the missile was then used to calculate the performance (using the Quo Vadis tool). These were based on derived engineering and technical details and the performance analyses of the missiles that were carried out using Quo-Vadis software for ballistic missile trajectory computation.

Image Analysis

Satellite Imagery analysis was carried out using the software Envi to measure and assess various dimensions of the Shaheen-III missile.

Figure 4: Shaheen III Missile Tests from Open Sources

Shaheen III was first tested in 2015, as per ISPR news. This was followed by tests in 2018 and 2021. The first test had been declared a success. The image analysis and calibration of the dimensions of the missile (as given in Table 3) were done. The Shaheen III missile has three stages. With respect to the missile dimensions of the 2015 version: stage 1 has a measured length of 7.445m, stage 2 has a length of 4.135m, and the RV length was calibrated to be 6.55m with a diameter of 1.4m. The total length of the missile is 18.35m by calibration. The missile dimension of 2021 seems to be different compared to the 2015 version. The 2018 test bore no news about the success or failure of the test for either an extended range or systems validation. As alluded to above, the article on the 2018 Shaheen-III test published in DDR assessed the  attempt to be a failed test. There are no  good images available in open sources for the 2018 test. It is assumed that the same dimensions may have been used in 2018 as in 2015 test. The time interval between the 2018 and 2021 tests also suggests that the 2018 test was a failure as brought out in the DDR article by ISSSP^[12]. The reasons for the failure of the 2nd test are unknown.

Table 3: Dimensions of Shaheen-3 missiles

To achieve an increased range for missiles from the Shaheen lineage there is a requirement for a third stage. This indicates that there is a third stage that is embedded in the Shaheen-III within its RV fairing. The dimensions of the RV have been apportioned for warhead, accessories and a PSAC as revealed by a study of Shaheen-1 and Shaheen-II missiles. There are dimensional changes between the 2nd and 3rd tests. The measurements show that there is an increase in the stage dimensions. The 1st stage length in the 2021 test indicates an increase in the propellant quantity for reaching maximum apogee before the separation of the 1st stage. The changes brought about in the 3rd test in 2021 have an impact on the propulsion parameters and hence on the range performance.

To determine the 3^rd Stage dimensions we have examined the RV length of Shaheen-I (No PSAC) and Shaheen-IA (incorporates PSAC). The reduced length of Shaheen-IA can be inferred as the L/V to be allotted for the associated warhead & electronics. It Is further assumed that this dimension for the warhead will be applicable for Shaheen-II and Shaheen-III missiles. From this, the 3^rd stage dimensions of Shaheen-III can be deduced.

Table 4: RV & Payload Dimensions for Shaheen 1(2003), 1A (2012), III (2015), III (2021)

The difference between Shaheen-I and Shaheen-IA is 0.5m. This means that the space for warhead and associated systems is 4 m. Shaheen-II and Shaheen-III missiles will have 0.5 m of space for PSAC in the RV setup. According to a calibration of the RV tests in 2021 and 2015, the RV has changed in length as seen in table 3. The reduction in the RV length of the 2021 test case leads to lower propellant loading and lower performance in the range from 2750 km to 1988 km as per the Quo-Vadis simulation.

The Quo Vadis simulations show that the maximum range achieved from the test parameters is 1988 km for the 2021 test. The difference in RV length between the 2015 test and 2021 is 1.75m. Keeping the 1-ton warhead mass a constant can lead to two possibilities. The first is that the same PSAC systems have been used with reduced fuel and oxidizer amount, and the second that Pakistan has achieved the capability to miniaturize the warhead. Since Pakistan uses uranium-based systems which are tested and verified, the use of plutonium is unlikely. Babur which may be using plutonium was tested with a 450 kg payload with china’s help^[13]. If similar help has been received for Shaheen-III in passive mode, the RV may be configured with the reduced dimensions. The Quo Vadis simulation based on the parameters gives us an RV mass at 1200 Kg, avionics at 75 kg, and PSAC system at 125 Kg. These results in turn mean that during the 2021 test, the Shaheen-III missile may not have achieved the declared range of 2230 km as stated in NOTAM Range estimates.

Quo Vadis Performance Analysis

The first stage impact point in the 2015 test is 147 km from the launch point (see figure 5 below). The stage 2 impact point for this missile was 1823 km from the launch point. The RV impact was 2760 km from the launch point. So, the maximum range achieved by the missile is estimated to be 2760km with an RV mass of 1425 kg.

During the 2021 test, the stage 2 impact point for this missile was 1939 km from the launch point. The RV impact was 1988 km from the launch point. So, the maximum range achieved by the missile is estimated to be 1988 km with an RV mass of 1200 kg for 2021. The related properties for the simulation are shown in table 5 below.

Table 5: Simulation Properties for 2015 and 2021 Shaheen III Test

Nominal performance estimate of Shaheen-3

Figure 5: Trajectory of Shaheen-3 during 2015 test along with NOTAM

The 2015 NOTAM indicates the maximum flight altitude of 692 Kilometres and a range of 2750 km. The stage 1 and 2 impact locations after burnout and separation from the missile can be seen in Figure 5 which happens to be in the Arabian Sea. The liquid motor along with fuel, oxidizer, and pressurant tanks could be packed with the avionics systems and warhead in an annular fashion inside the RV. The total RV mass is estimated at 1.425 tons which consists of a warhead weighing 1 ton. The entire 18.35m long vehicle (Length / Diameter = 13) constitutes the first and second stage, inter-stage, and RV. The estimated range covered by the missile with above-mentioned stage parameters using Quo Vadis is 2760 km touching a maximum altitude of 600 km.

Figure 6: NOTAM issued for 2021 Shaheen-3 test

The NOTAM issued for the 2021 test indicates a maximum range of 2230 km which is far less than the NOTAMs issued in 2015 and 2018. Nearly 2 m length reduction of RV can be seen in 2021 compared to the 2015 Shaheen-3 missile which suggests a much smaller liquid motor package with a smaller sized warhead has been used. The total vehicle length also is smaller than the 2015 missile with an L/D of 12.5. This reduced range can also be explained by the significant length reduction in the RV portion of the 2021 Shaheen-3 missile version. The 1.2-ton RV consists of a warhead of 1 ton and the remaining constitutes the avionics systems and liquid package. The fuel and oxidizer carried in the 2021 test are significantly less than that seen in the 2015 test which makes the RV length reduction obvious and subsequent range difference found.

Note: The lateral error computes in Quo Vadis and declared in NOTAM is similar. The lateral error difference between NOTAM and Quo Vadis simulation is 0.03 per cent.

Conclusion

The modified design has resulted in a shortened RV and 3rd stage with some adjustments for performance upgrade. Overall, the missile appears to be shorter by approximately 10% in the achievable range in comparison with the NOTAM declaration in 2021. However, it is likely that the range achieved is shorter than the originally planned distance. Hence the missile may have failed to meet the desired targets. There may be re-tests to validate the system parameters. It is to be seen whether Pakistan will freeze the design at this point or has plans to incrementally increase the performance. It would be interesting to see how the scenario unfolds.

Epilogue: The recent successful test of Shaheen-III in February 2022, shows re-testing of the Shaheen-III system with the overall length being 17.5m. The RV is shorter than its previous versions. The reduction in the RV length has been consistent since the 2015 tests. Though there is no direct cause that can be associated with the reduced RV length, the general assumption is that through Chinese technical assistance and other measures, Pakistan has achieved both nuclear and conventional warhead capability. Pakistan has traditionally used uranium-based nuclear weapons systems. They have not carried out any plutonium-based tests but test data of plutonium-based warheads may likely have been received from China, permitting them to carry out miniaturization in the RV section thereby reducing this section’s length.

Amit Mukherjee is an Assistant Professor in ISSSP NIAS Bengaluru, 

Surya S. is a Project Associate in ISSSP NIAS Bengaluru.

Acknowledgement: We are grateful to Prof. Rajaram Nagappa for his vision and esteemed guidance during the preparation of the work. We would like to extend our thanks to Director NIAS, Head of the Programme and Faculty, of ISSSP and NIAS for their constant support and encouragement.

 References

1.  Hufbauer  Gary Clyde (PIIE), Schott Jeffery J.  (PIIE), Kimberly Ann Elliott, Ann Kimberly (PIIE) and Barbara Oegg (PIIE), Case 79-2. US v. Pakistan (1979–: Nuclear Missile Proliferation), May 1, 2008 https://www.piie.com/commentary/speeches-papers/case-79-2.
2. “Pakistan Missile Milestones – 1961-2014.” Wisconsin Project on Nuclear Arms Control, 1 September 2014, www.wisconsinproject.org/pakistan-missile-milestones-1961-2014/. ↑
3. “DF-11.” Missile Threat, 3 August 2021, www.missilethreat.csis.org/missile/dong-feng-11/. ↑
4. “Ghaznavi (Hatf 3).” Missile Threat, 3 August 2021, missilethreat.csis.org/missile/hatf-3/. ↑
5. Nagappa, Rajaram. “An Assessment of Ballistic Missile Production Capacity of Pakistan.” NIAS, September 2007, www.nias.res.in/publication/assessment-ballistic-missile-production-capacity-pakistan. ↑
6. Elleman, Michael. “North Korea-Iran Missile Cooperation.” 38 North, 22 September 2016, www.38north.org/2016/09/melleman092216/. ↑
7. ibid, op. cit. 6. ↑
8. “Ababeel.” Missile Threat, 31 July 2021, www.missilethreat.csis.org/missile/ababeel/. ↑
9. Missiles of Pakistan.” Missile Threat, 10 August 2021, www.missilethreat.csis.org/country/pakistan ↑
10. Riffath, Kazi. “Possibly Failed Pakistani Ballistic Missile Test Raises Doubts About Overall Capability.” Delhi Defence Review, 10 December 2018, www.delhidefencereview.com/2018/12/10/possibly-failed-pakistani-ballistic-missile-test-raises-doubts-about-overall-capability/. ↑
11. “Pakistan Missile Chronology.” NTI, May 2011, p. 6, www.media.nti.org/pdfs/pakistan_missile.pdf ↑
12. ibid, op. cit. 12 ↑
13. Times Now. “Pak’s ‘India Specific’ Nuke Arsenal Exposed.” The Economic Times, 1 Sept. 2009, economictimes.indiatimes.com/news/politics-and-nation/paks-india-specific-nuke-arsenal-exposed/articleshow/4960053.cms. ↑

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