Jeffrey LewisEverythin's Bigger in Texas: Sea-based X-band Radar

San Antonio Express-News staff writer Jeorge Zarazua got a chance to climb around the Missile Defense Agency’s gigantic Sea-based X-band Radar (SBX)—a missile defense radar mounted on a self-propelled oil-drilling rig.

The SBX is larger than a football field, which means its journey from Texas to Hawaii (and points beyond) will not include a trip through the Panama Canal. Officials, Zarazua report, had hoped to put the SBX out to sea before June 1 to beat the hurricane season. This could be exciting.

The SBX is also one of the few missile defense activities undertaken by the Bush Administration that required relief from the ABM Treaty. X-band radars are supposed to help discriminate warheads from any accompanying decoys or debris.

General Obering called the completion of the SBX a “major milestone” for testing that “also gives us an operational capability from a North Korean threat.”

Stephen Moore explains that by “operational capability,” Obering means SBX will precisely track North Korean warheads while our missile defense interceptors remain stuck in their silos.

Both the decision to build SBX instead of a more capable ground-based radar in Alaska and recent test failures stem from a series of deliberate choices by the Bush Administration to meet the arbitrary 2004 election, er, end of year, deadline set by the President. In other words, the President traded the ability to defeat Kim Jong-Il for the ability to defeat John Kerry.

What a guy.

Bradley Graham of the Washington Post obtained an unclassifed report by “an outside panel chartered by the Pentagon” that concluded “the rush to deploy a national antimissile system last year led to shortfalls in quality controls and engineering procedures that could have better assured the system would work.”

“Manage quality first and then schedule,” the authors—William Graham, Willie Nance, and William Ballhaus Jr.—sagely advised.

[See my post on the IRT Final Report]

Testing shortfalls, however, are only part of the issue. SBX was one of three major changes the Bush Administration made to the Clinton-era C1 NMD architecture to leave the system less capable even if it works as planned:

  • The Bush Administration will place only 20 interceptors instead of 100, with 16 in Alaska and 4 in California.
  • Instead of building an X-band radar in Shemya, Alaska, the Bush Administration will build a Sea-based X-band radar and upgrade the early warning radar at Shemya.
  • The Space-based Infra Red System (SBIRS) Program has been restructured, with SBIRS-High launches scheduled for 2006-2010. SBIRS-low is now the Space Tracking and Surveillance System (STSS), with non R&D launches scheduled for 2011.

The SBX radar is less capable than the ground based radar originally planned for construction at Shemya—though the difference may not matter as much as, oh say, interceptors that don’t intercept:

The SBX is smaller than the previously planned Shemya XBR. According to an MDA report, the SBX will have only 50–65 percent as many transmit/receive modules as the planned Shemya XBR, and a correspondingly reduced aperture, reducing detection range to 4,800 km (for the 65 percent populated SBX) rather than the XBR’s 6,700 km (MDA 2002, p. v). This reduction may not be significant, since a detection range of 4,500 km corresponds to a radar horizon altitude of about 1,500 km, which is roughly the maximum altitude of a long-range missile. However, the specified detection range is against a target with an RCS that is not publicly known. If the actual RCS is less than this value (for example, if stealth is used as a countermeasure), than the larger power and aperture of the XBR relative to the SBX might have been useful. In addition, the larger aperture and power of the XBR relative to the SBX will give it a higher signal/noise ratio against a specific target at any given range, and a narrower beam providing somewhat better tracking, resolution, and decoy discrimination capability. However, these differences are not large, and for the purposes of roughly estimating the capabilities of these systems, it appears reasonable to assume that the somewhat smaller size of the SBX relative to the XBR is not a significant issue. Other factors may be of more significance.


More importantly, since the SBX is viewed as a test asset, it has a number of serious deficiencies when viewed from the perspective of an operational system (MDA 2002). Unlike the planned Shemya XBR it does not have dual redundant electronics, so it is less reliable. Unlike the planned Shemya XBR, it will not be hardened against the electromagnetic pulse from a high altitude nuclear explosion. And it does not have the fiber optic cable connection that was planned to give the XBR secure communications.

So, the bad news is that our missile defense system sucks. The good news, however, is that the President was able to tell Jim Lehrer during his debate with John Kerry that his administration will “be implementing a missile-defense system relatively quickly.”


  1. EARL (History)

    A mobile sea based radar, well sort of mobile, on a self propelled oil rig ?? Visions of Cheney in a Nehru jacket with a big fuzzy kitty in his lap. Will the frickin’ sharks with laser beams be next. I wonder if that is a submersible unit, since that is the likely destination of something that mobile…….

  2. Allen Thomson (History)

    I’ve been following the SBX since its Shemya days with considerable interest. (Use Google Groups on sci.military.naval to find various SBX factoids that have been deposited there over time.)

    A couple of interesting questions concern the floating platform itself, apart from the radar that sits on it. The platform (called first “Moss Sirius) and now “Moss 5”) is a CS-50 model built in Vyborg, Russia for the Norwegian Moss Arctic company, which then sold it to Boeing, which was acting as an agent for MDA.

    It isn’t at all clear where the money for Boeing’s purchase of Moss Sirius in late 2002 came from, and indeed there was Congressional language a few weeks before the purchase prohibiting SBX money from being used for a platform. No appropriation of monies for Moss Sirius has been located to date, so was there a violation of the Anti-Deficiency Act?

    And, since the platform is of Russian provenance, might the Iran Non-Proliferation Act have been bent a bit despite the Norwegian middleman?

    Finaly, since there are some hints that the radar, now called SBX-1, may be followed by SBX-2, will another Russian platform be procured for it?

    See, by the way, another recent informative SBX article.

  3. Pavel Podvig (History)

    My memo on Vyborg and SBX ( is about a year old (and in Russian), but might still be interesting. As I understand, Vyborg had no idea that the platform is going to be used for the radar. They reportedly got a contract for a second one, but I couldn’t find anything specific about it.