Ninety Percent Of The Time, The Missile Works Every Time: Iranian Missile Failure Rates During True Promise II

This is the first in a series of posts I am writing on True Promise II to complement the piece I did on ABM expenditures during the 12 Day War. I hope it will also serve as a corrective to some poor quality information that has been circulating since the start of the missile exchanges between Israel and Iran. This first post will focus on determining the reliability of the Iranian missile force. The second will discuss Israeli missile defense performance during True Promise II, building on the excellent work done recently by Steve Fetter and David Wright published in Washington Quarterly which I encourage everyone to read.

One of the most common talking points around True Promise I and II is that around 50% of Iran’s missiles failed during flight, before even approaching Israel. This statistic was widely reported after True Promise I in outlets like Wall Street Journal and Associated Press based on comments by a number of U.S. officials. Given the very small number of ballistic missile impacts in Israel, that could certainly be true. But, this failure rate is often incorrectly assumed to apply to the reliability of Iranian missiles during True Promise II and the 12 Day War. In fact, Iran’s missile force had a failure rate of about 10% during True Promise II based on public statements by American, Iranian, and Israeli officials and video evidence.

The first place to start are the statements of public officials from the three countries. The Pentagon Press Secretary, Major General Pat Ryder, stated Iran launched “approximately 200 ballistic missiles” in the attack.  Iranian statements agree with the 200 missile figure. Former IRGC Commander in Chief Hossein Salami said in a video from the operational headquarters that 200 missiles were fired. Similarly, after the strike IRGC General Ebrahim Jabbari claimed “we launched 200 missiles recently.” 

Israeli officials disagree about the number. An IDF spokesperson told CNN their initial estimate was Iran had fired “approximately 180 projectiles” at Israel during the attack. Later, IDF spokesperson Rear Admiral Daniel Hagari said more than 180 ballistic missiles were launched during the strike. 

Why the discrepancy? There are two interesting conclusions we can draw from the difference in the numbers reported by the Israelis and the Americans and Iranians. The first is that the difference reflects the failure rate of Iranian missiles. The 20 missile difference between 200 and 180 is about 10% of the strike, implying 10% of the Iranian missiles failed. The Iranians fired 200 missiles, 20 failed during the boost phase, and the remaining 180 missiles climbed up over the mountains and were detected by Israeli radars. The difference boils down to the fact that the Iranians are reporting the number they fired while the Israelis are reporting the number they detected.

But why did the U.S. assessment agree with the Iranian number rather than the Israeli number? The answer is probably that for early warning the U.S. relies on infrared sensors on satellites like SBIRS which can detect a ballistic missile within seconds of launch. It seems likely the U.S. was able to detect all 200 Iranian launches more or less immediately, rather than having to wait until later in the boost phase when they came into the detection range of Israel’s radars. This implies a second interesting conclusion: The U.S. does not appear to be sharing launch detection data with the Israelis. Given the IDF’s repeated statements that 180 missiles were fired at Israel it seems the U.S. passed along tactical warning of the launch but not more granular data, like numbers of missiles fired. They may not have even shared the early warning at all. Perhaps the U.S.-Israeli relationship is not as unlimited as it seems?

Video evidence helps firm up the 10% failure rate suggested by public officials statements. The CNS Open Source Team collected a number of videos from Iran of the missile launches posted to social media.

We then geolocated those videos, and counted the number of failures during launch. Of course, this comes with the caveat that the videos don’t cover the full burn of each missile, so there may be some failures not captured in this dataset.

Using this method, we have geolocated videos of just under a quarter of the missiles used during the strike, a pretty representative sample size. We observed that 8-9% of the missiles launched failed, often dramatically. This failure rate aligns well with that drawn from the official statements, increasing our confidence in the 10% failure rate.

What explains the dramatic reduction in Iran’s failure rate from 50% during True Promise I to 10% in True Promise II? It likely reflects a change in strike composition. The Iranians used many of their older, less reliable liquid propellant missiles during True Promise I, like the Shahab-3 variants. By contrast, True Promise II featured more modern solid propellant missiles like the Kheibar Shekan and Fatah-1. As the Iranians burned through their older systems and began putting together strikes using their more recently developed missiles, their reliability improved. One of the strikes which experienced no failures during True Promise II was a 15-missile salvo near Tabriz which consisted of only solid propellant missiles, probably Kheibar Shekans, underscoring this trend.

What does this improved reliability mean for the Iranian missile force? The 10% failure rate suggests that in a future conflict the Iranians should be able to generate larger, well coordinated strikes, similar to the one they carried out during True Promise II. If this failure rate is representative, True Promise I is likely an outlier, the nadir of Iranian missile performance, reflecting the older liquid systems used. This reality likely informed Israeli strategy during the 12 Day War. Facing the prospect of larger, well coordinated, and more reliable strikes, it is unsurprising that the Israelis pursued a more aggressive missile defeat strategy, attacking launchers and missile bases left of launch rather than only playing defense. As Iran reconstitutes its missile program after the 12 Day War, any future conflict will likely demand Israel pursue a similarly intense missile defeat strategy if they wish to prevent that type of strike.

Ultimately, despite the poor performance during True Promise I in April 2024, the Iranian missile force can actually be quite reliable.