GPS IIA Satellites a Concern for OCX

May 3, 2012  - By
Image: GPS World

One of the long-standing issues for support of IIA vehicles after the future GPS Operational Ground Control Segment’s (OCX’s) ready-to-operate (RTO) date, which should fall in December 2016 at the latest, is what ground command-and-control (C2) system will steer GPS IIA satellites, do navigation uploads, and so on. The issue is that AEP, the current C2 system, will no longer be available once the transition to OCX takes place, and OCX has no requirement to control IIA satellites.

The OCX program, which struggled early, is now under new Program leadership within Raytheon Space Systems, and while Ray Kolibaba, the new OCX program manager, is making great progress, OCX does not need to be burdened with additional requirements at this stage of the program.

Just how big an issue is GPS IIA C2? Initially the Aerospace projections were that there would only be one or two GPS IIAs left on orbit in 2017, and it was not worth the costs to include the C2 software for the legacy system in the new software code. However, I have long maintained that Aerospace and Space Missile Systems Command (SMC) neglected to count the residual satellites, maintained by Launch, Anomaly, and Disposal Operations (LADO), which might very well actually amount to 3–4 additional IIAs. Added to the two IIAs on orbit, this could amount to six IIA SVs that need to be maintained.

The solution announced during the National Space Symposium (NSS, April 16–19) by General William Shelton, the four-star chief of Air Force Space Command, is to fund the current LADO operator, Braxton Technologies, to build in this support for the IIAs. This is significant for several reasons: One of course is that it solves the IIA C2 issues, it does it now, and at a relatively modest cost, and it utilizes more of the capabilities of the Braxton Technologies’ LADO software. Additionally it provides a true backup capability for assets on orbit that become increasingly valuable as the number of available launch slots for GPS decreases.

Braxton Technologies initially demonstrated this capability years ago in a lifeboat drill during the transition to AEP, but the navigation upload capability was never maintained for LADO after the successful transition. This is certainly a step in the right direction and provides a simple solution to a vexing problem that has plagued the GPS program for the last several years.

Dual Launch. I asked General Shelton if he would support an approach that would allow the United States to go to dual launch of GPS III on vehicles 5–6 instead of waiting until 8–9 as planned today. He said the Air Force would certainly support that, and is looking at making it possible with vehicle 7 currently. That will come even sooner if the program advances with glitches.

I also asked him about the gap between GPS III launch and OCX RTO. The gap seems to be getting wider, not narrower, and he agreed that OCX could probably not move to the left, and GPS III has moved significantly to the left, so this is still an issue that needs to be addressed. There are plans in place, but the recent budget activity has caused some uncertainty.

Sequestration. On the subject of sequestration — a highly charged Congressional effort to force another $500 billion-plus in additional defense cuts — General Shelton said it would amount come on top of the approximately $487 billion already cut from programs, and that many space programs might be unsustainable in their current mode if that occurs.

However, the U.S. Armed Services have been informed by the White House Office of Management and Budget not to make plans for sequestration. So right now, the services and other agencies of the U.S. government have been forbidden to make programmatic decisions based on a possible sequestration. Interesting.

By the way, attendance at NSS this year surpassed 9,000.

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