Telemetry Problems in GMD Tests. When Were They Discovered? Did they Affect the Assessment of FTG-02? (April 24, 2012)

In May 2008, MDA cancelled the planned GMD test FTG-04, which would have been the third intercept test of an operational GBI interceptor.  MDA told GAO that the interceptor telemetry problem that led to this cancellation was discovered in February 2008, but MDA knew about telemetry problems with the interceptor by at least December 2006.  Could the telemetry problem have played a role in the classification of the earlier intercept FTG-02 as a “successful intercept?”

 

In May 2008, MDA Director Lt. Gen. Henry Obering first postponed and then cancelled the next planned intercept test, FTG-04, of the U.S. Ground-based Missile Defense (GMD) national missile defense system.  FTG-04 was replaced with a non-intercept test (FTX-03), and the next intercept test, FTG-05, was eventually conducted in December 2008. 

At a July 2008 press conference, General Obering described the cancellation of FTG-04 as being due to a faulty telemetry card on the Exo-atmospheric Kill Vehicle (EKV) on the Ground-Based Interceptors (GBIs) to be used in the test.[1]  He stated that while this problem affected only testing and not operational use of the interceptors, had MDA proceeded with FTG-04 as planned, “we had at least a 20 percent chance we would lose all data in the test.”

In early 2009, the General Accountability Office (GAO), at the request of the Senate Armed Services Committee, reported on the cancellation of FTG-04.[2]  The GAO confirmed that FTG-04 had been cancelled due to a telemetry problem with the EKV, specifically a defective Pulse Code Modulation Encoder (PCME) device.  The GAO found that the PCME had at least here manufacturing defects:

            — Gold embrittlement due to lack of pretinning

            — Insufficient oscillator stand-off height (causing thermal stresses)

            — Three missing washers (causing circuit board bending)

In addition, a chip on the PCME device had clock that was asynchronous with a part on another component.  The GAO cited estimates that this asynchronous chip problem alone would have led to an 18% to 48% chance of at least some telemetry loss on any given flight test. 

Worse, these telemetry defects did not just affect the EKV that was to have been used for the cancelled test, but were believed to affect all the operational EKVs that had been produced so far, including the ones on the 24 interceptors that were then deployed in silos.  The GAO agreed with MDA that these problems would not affect operational performance, but only the transmission of test data. 

GAO reported that MDA discovered the problem with the telemetry card in February 2008.  Here is the timeline from the GAO report:

 

However, MDA had known about problems with the PCME device at least since December 2006.  In fact, it appears that problems with the PCME card were discovered as a direct result of the first test of the operational EKV, FTG-02, held on September 1, 2006.

In December 2006, Aviation Week and Space Technology quoted MDA Director Obering as stating that FTG-02 revealed two problems that needed to be fixed before the next test.[3]  One of these problems required MDA to “redesign a pulse code modulator on the GMD interceptor.”  Further, Obering said that although the pulse code modulator did not cause problems with FTG-02, if not corrected, it would in the future cause a 20% chance of telemetry loss (the same percentage he cited in his July 2008 press conference). 

Since all the PCME cards produced up to 2008 were defective, including those on the 24 GBIs already deployed in silos, and the first flight of an operational interceptor test was conducted two years after the first interceptor deployment, it is clear that all the operational GBI flight tests conducted prior to 2008 must have had defective telemetry device.  There were three such tests, FT-1, a non-intercept test held on December 12, 2005, and two intercept tests: FTG-02 on September 1, 2006 and FTG-03a on September 28, 2007.  Moreover, FTG-03a was conducted well after problems with the telemetry were discovered.  

As discussed in the previous post (April 19, 2012), MDA considers the first intercept test of the operational GMD interceptor, FTG-02, to be a complete success, resulting in a successful intercept of its target.  However, the Pentagon’s Director of Operational Test and Evaluation has assessed FTG-02 test as not achieving a kill.  Could a loss of data due to a telemetry problem have contributed producing these seemingly contradictory assessments?

As noted above, following the FTG-02, MDA Director Obering said that the telemetry defect did not cause problems with the test.  However, something unexpected must have occured with the telemetry, because the telemetry problem was discovered as a result of this test.

Moreover, MDA does not have complete data from the kill vehicle for FTG-02.  According to DOT&E, cited by GAO in early 2009, only two intercept attempts — FTG-03a and FTG-05 — had produced complete interceptor and EKV data.[4] In addition, GMD program officials told GAO that while FTG-02 had provided limited intercept data for assessment purposes, this data was incomplete and could not be used to fully validate and verify the models and simulations.[5]  Finally, in October 2008 [that is after FTG-02 and FTG-03a but before FTG-05], MDA stated that the cancellation of FTG-04 had eliminated a second opportunity to anchor the models of EKV-fielded software.[6]

Thus it is clear that not only did FTG-02 test use defective telemetry components, but it also collected at best only partial information on the intercept attempt.  This missing data is not necessarily due to a telemetry problem, but taken together with DOT&E’s assessment that this test did not achieve a kill, strongly indicates that the outcome of FTG-02 was more complex than it being simply an unqualified successful intercept as MDA currently claims.


[1] U.S. Department of Defense, News Transcript, “DoD News Briefing with Lt. Gen. Obering from the Pentagon, July 15, 2008. 

[2] U.S. General Accounting Office, “Defense Acquisitions: Production and Fielding of Missile Defense Components Continue with Less Testing and Validation Than Planned,” GAO-11-372, pp. 90-91.

[3] Amy Butler, “Dramatic Pause; Missile Defense Test Slip Could Draw Scrutiny from New Congress,” Aviation Week and Space Technology, December 18, 2006, p. 33.  The other problem was said to be a software problem that could affect the GBI interceptor’s “performance and reliability.”

[4] U.S. General Accountability Office, “Defense Acquisitions: Production and Fielding of Missile Defense Components Continue with Less Testing and Validation than Planned, GAO-09-338, March 2009, p. 93.

[5] GAO, GAO-09-338, p. 30.

[6] GAO, GAO-09-338, pp. 93-94.

Advertisements
Leave a comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: