Universal spacecraft data interface developed for NASA

COLORADO SPRINGS, Colo. - An all-purpose interface chip that replaces a board populated with discrete devices is now in production at UTMC Microelectronic Systems Inc. in Colorado Springs, Colo.

Jun 1st, 1997
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By John Rhea

COLORADO SPRINGS, Colo. - An all-purpose interface chip that replaces a board populated with discrete devices is now in production at UTMC Microelectronic Systems Inc. in Colorado Springs, Colo.

UTMC officials expect the chip, which they developed under sponsorship of the National Aeronautics and Space Administration (NASA), to be flying in spacecraft within two years.

The device is an application-specific integrated circuit that UTMC officials call the essential services node (ESN); it combines on one chip the company`s UT69R000 16-bit microcontroller, 1553/1773 data bus interfaces, timers, and other support functions.

The idea originated among microelectronics experts at NASA`s Goddard Space Flight Center in Greenbelt, Md. Designers at Goddard are always trying to reduce weight and power consumption on their meteorological, Earth-observation, and other spacecraft.

The project began about two years ago, recalls Greg Lannan, senior staff engineer at FirstPass Inc. in Castle Rock, Colo., when engineers from Goddard`s Flight Data Systems Division approached his company to design such a universal device. NASA officials put up about $120,000 in seed money, and FirstPass engineers hooked up with UTMC to produce the chips.

Engineers fabricated the first ESNs at UTMC`s former facility in Colorado Springs, which subsequently was sold to Rockwell International, using the 1.2 micron CMOS process. UTMC and FirstPass officials are selling the devices to Goddard, which provides them to spacecraft data handling subsystem contractors on a government furnished equipment basis.

If the devices catch on, UTMC officials plan to shift production to the 0.8-micron CMOS process fab at Lockheed Martin Federal Systems in Manassas, Va.

Prices are $4,900 each for bare die or $6,700 packaged in either 208-pin gate arrays or 196-lead flatpacks in 25-unit quantities. The devices are radiation-hardened for space from 100 kilorads to 1 megarad total-dose exposure.

Spacecraft integrators can reduce weight and power consumption by factors of three or four - even before including the costs of assembly, test, and debugging - by replacing a board with a chip, estimates Anthony Jordan, standard products marketing manager at UTMC.

Moreover, since they are universal devices, the ESNs can be designed into any of the data-handling nodes of a spacecraft that require a network interface.

FirstPass`s Lannan estimates a typical spacecraft has 15 to 25 nodes, which divide into two categories: the "housekeeping" functions common to all spacecraft that keep them operating properly and in the correct orbit; and the mission-specific functions of individual payloads.

Lannan estimates the ESNs can fit 90 to 95 percent of the common spacecraft functions and some as-yet-undetermined number of payloads, depending on the type of mission and telemetry bandwidth required.

Another possibility, in which military leaders have shown interest, is using the devices in guidance, navigation, and control of launch vehicles. Additional information is available from the FirstPass World Wide Web at www.firstpass.com/.

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A spacecraft data interface from UTMC Microelectronic Systems is an ASIC that combines a 16-bit microcontroller, 1553/1773 data bus interface, timers, and other support components.

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