Is this actually necessary? Like, the point of the B-2 is to be able to penetrate air defenses. Do the Houthis actually have much by way of air defenses?

kagis

This is from six years back, but apparently at the time, Iran was sending them air defense hardware, so that might be it.

https://www.washingtoninstitute.org/policy-analysis/irans-support-houthi-air-defenses-yemen

According to the Gulf coalition and the internationally recognized Yemeni government, Iran has been violating the UN arms embargo by trying to provide Houthi rebels with advanced surface-to-air missile systems. The smuggling of Iranian-built Sayyad-2C SAMs and passive flight-tracking equipment could worsen the air-defense threat to U.S. allies such as Saudi Arabia and the United Arab Emirates, jeopardizing efforts to hammer out a peace settlement in the process.

Also from six years back, and more in-depth:

https://warisboring.com/the-houthis-do-it-yourself-air-defenses-3/

When the Saudi-led coalition intervened in Yemen’s civil war in 2015, it quickly neutralized most of the Houthis’ air defenses. Nearly all of the radars and launchers belonging to the Houthis’ five air-defense brigades were destroyed by mid-April 2015.

Elements of two air-defense brigades managed to recover and hide most of their equipment. Correspondingly, the air defenses of the Houthi-dominated coalition were limited to a miscellany of man-portable air-defense systems, light anti-aircraft cannons including U.S.-made Vulcan guns and various heavy machine guns.

Through 2015, such weapons were responsible for the losses of one Moroccan and one Bahraini F-16C, two Saudi AH-64As and up to a dozen various UAVs. However, the longer the war went on, the clearer it became that they weren’t enough to defend Houthi forces from the Saudis and their allies.

Indeed, the aircraft loss rate for the Saudi-led coalition decreased by an order of magnitude in 2016. While two different Saudi helicopters were written off during combat operations over Yemen, Houthi air defenses were responsible for the downing just one CH-4 Wing Loong UAV.

Understanding that more efficient measures were required, Yemeni engineers with the Missile Development & Research Command worked feverishly on repairing available air-defense equipment and improvising new ones. In January 2017, they announced they had repaired one S-75/SA-2 surface-to-air missile system.

And on Jan. 20, they went as far as to claim the downing of a Saudi F-15 over Sana’a. Actually, they achieved nothing, and the system in question was soon tracked down and destroyed by the Saudi-led coalition.

One of solutions developed by the MRDC was to take air-to-air missiles from stocks of the former Yemeni air force and attempt deploying them for air-defense purposes. This idea is not new. Back in 1999, the Serbs adapted Russian-made R-60/AA-8 and R-73/AA-1 air-to-air missiles for surface-to-air missions.

Furthermore, the Houthi-led coalition has enough experienced and skilled personnel to undertake such an adaptation on its own – and it’s in possession of significant stocks of air-to-air munitions at bases of the former Yemeni air force.

Yemen acquired a stock of Soviet-made R-60MK/AA-8 missiles back in 1980, together with MiG-21bis and Su-22 fighter-bombers. A small batch of R-73/AA-11 missiles was acquired by the former South Yemen in 1994 for deployment with MiG-29 interceptors. An even larger number of R-27/AA-10, R-73s, and R-77/AA-12s were acquired by Sana’a after 2001 together with up to 36 MiG-29SMs and UBs.

The challenge was adapting such weapons for deployment from the ground, and without the support of the fire-control systems in the aircraft that usually carry them.

Active radar-homing missiles such as the R-77 and semi-active radar-homing missiles such as the R-27R would require the adaptation of at least one of the N019MP radars and related fire-control systems delivered to Yemen together with the MiG-29SMs.

Not only was this a complex undertaking, but most of the necessary systems were destroyed early during the war when the Saudi-led coalition systematically tracked down and knocked out every single MiG it could find.

Instead, engineers at the MRDC opted to adapt infrared homing missiles as SAMs. That effort required the adaptation of APU-60 and P-12 launch rails — for the R-60 and R-73, respectively — on supports mounted on pick-up trucks plus a reliable supply of electric power and liquid nitrogen to cool the seeker heads.

The first such improvisations were deployed in combat in February 2017, and by June the Houthi-dominated coalition claimed the downing of five fighter-bombers, one helicopter and one UAV.

Whether any of the missiles actually scored a hit remains unclear. What is certain is that a Jordanian F-16AM crashed over southern Saudi Arabia while returning from a combat sortie over Yemen on Feb. 24, 2017.

The situation remains the same in early 2018. The reality is that air-to-air missiles are designed to be fired from fast-moving aircraft that are already airborne. The motors of air-to-air missiles are relatively small and light in comparison to the motors of surface-to-air missiles. The latter are big, heavy and far more powerful.

For example, the rocket motor of the Patriot PAC-2 weights 1,200 pounds and develops more than 20,000 pounds of thrust in order to accelerate the missile to speeds in excess of Mach 4.

Without such motors, the effective range of air-to-air missiles fired from the ground is dramatically shorter than if they are fired from the air. Even an R-27 is unlikely to reach a target more than five miles away.

At least as important is the issue of fire-control. It’s not enough to point a guided missile in the direction of its target and fire. All anti-aircraft missiles function better if locked-on at their target before launch.

Engineers at the MRDC found a solution by coupling one of three U.S.-made Flir Systems ULTRA 8500 turrets – delivered to Yemen back in 2008 – with makeshift controls for their “new” SAMs. One such SAM enabled them to fire the R-27T that narrowly missed a Saudi F-15 over Sana’a on Jan. 7, 2018.

Ironically, while the first related reports only cited the firing of the missile, the Houthi-controlled media in Yemen and all Iranian media outlets were quick to convert that report into a claim that the targeted F-15 was shot down.

Actually, the F-15SA in question came away with minor damage. F-15SAs are equipped with digital electronic warfare systems and common missile warning systems made by BAE Systems and designed not only to recognize missile attacks, but also to warn the crew and automaticallydeploy countermeasures.

The same is true of the Tornado IDS the Houthis claimed to have shot down over northern Sa’ada province on the same day. Actually, the aircraft in question suffered a failure of its oxygen system that caused a fire inside its cockpit and prompted the crew to eject.

While Houthi and Iranian media associated these two claims with the deployment of a new surface-to-air missile, the adaptation of R-73s and R-27s as SAMs — supported by ULTRA 8500 turrets — hardly qualifies as new. It’s also not as effective as the Houthis claim. The missile that targeted the Saudi F-15SA over Sana’a on Jan. 7, 2018 was the first ever to get that close to its target.

Deployment of such weapons didn’t escape the attention of Saudi and allied air forces and intelligence agencies. On the contrary, representatives of the Saudi-led coalition confirmed their appearance during one of their regular briefings for the press in early November 2017.

They also published two photographs showing installations of R-27T and R-73 missiles on pick-up trucks operated by the Houthi coalition. Ironically, the Iranians – the party said to be supporting the Houthis – seem to have learned about the appearance of such SAMs from Saudi media.

In comparison, MRDC’s work on repairing some of the coalition’s SA-9 vehicles proved at least slightly more effective. One of these has managed to shot down a U.S.-operated MQ-9 Predator UAV over Sana’a on Oct. 1, 2017.

In a quick skim, I don't see much more-recent than 2018. There's this from January of 2024:

https://www.timesofisrael.com/liveblog_entry/us-says-it-destroyed-houthi-surface-to-air-missile-which-was-prepared-to-launch/

US says it destroyed Houthi surface-to-air missile which was prepared to launch

US forces have struck and destroyed Yemen’s Houthi surface-to-air missile which was prepared to launch, the Central Command says in a statement.

“US forces identified the missile in Houthi-controlled areas of Yemen and determined that it presented an imminent threat to US aircraft,” it adds.

And this from September 2024:

https://www.defensenews.com/news/your-military/2024/09/16/houthi-rebels-claim-they-shot-down-another-us-mq-9-reaper-drone/

DUBAI, United Arab Emirates — Yemen’s Houthi rebels claimed Monday that they shot down another American-made MQ-9 Reaper drone, with video circulating online showing what appeared to be a surface-to-air missile strike and flaming wreckage strewn across the ground.

Saree said the Houthis used a locally produced missile. However, Iran has armed the rebels with a surface-to-air missile known as the 358 for years. Iran denies arming the rebels, though Tehran-manufactured weaponry has been found on the battlefield and in seaborne shipments heading to Yemen despite a United Nations arms embargo.

Wikipedia doesn't have a lot on this 358:

https://en.wikipedia.org/wiki/358_missile

I'm guessing, from the fins in the image, the fact that it apparently uses a turbojet engine, and the description as a "loitering munition" that it's probably not the fastest-moving missile in the world, though.

So, I'm guessing from that that they have some level of surface-to-air weaponry above MANPADS, but it doesn't sound like a lot of capability.