Site: Orbital Sciences Corporation (formerly CTA Space Systems)
1521 Westbranch Drive
McLean, VA 22102

Date Visited: May 15, 1997WTEC Attendees: C. Bostian (report author), R. DePaula, S. Goldstein, N. Helm, C. Mahle



Orbital Sciences Corporation, which recently acquired CTA Space Systems, is known primarily as a maker of one-of-a-kind small satellites for DOD and NASA. Twenty-six of its spacecraft have flown. INDOSTAR, a geostationary "litesat" is its first GEO and largest commercial project. The company tries to leverage future projects from current ones: almost every project that OSC does has some elements of testing new systems. Sometimes the company develops components in-house for one program that it might buy from vendors for another. Its in-house capabilities include sun sensors, reaction wheels, onboard computers.

OSC primarily builds buses rather than payloads.

OSC sees its market niches as building extremely tiny satellites, getting high efficiencies from a few kilograms of payload. The Clark satellite is an example. There OSC is teamed with Lockheed Martin. Obviously Lockheed Martin has excellent capabilities for building large satellites, but when the spacecraft size and complexity drops below a certain level, OSC is competitive.

OSC's international competition is Surrey and, in some cases Matra Marconi.

OSC does not see itself entering the mass market for LEOs.

OSC has bundled satellites and earth stations as a package. As a result, the satellite telemetry and control software is not standard.


OSC sees cheaper launch vehicles as a primary industry need. Other cost drivers are transponders and solar arrays.

As a small company, OSC is concerned with accessing and using existing knowledge. It feels a lack of one place to go where it could find out about, for example, a particular standard: how should it be used and what are the pitfalls? We discussed some federal technology transfer programs. OSC staff did not seem to be aware of these.


INDOSTAR is a five-transponder bent-pipe satellite for Indonesian TV broadcasting. OSC bought the chips and built and programmed the computer that runs the spacecraft. The engineers do not feel that they are pushing the state of the art. The antennas were built by Composite Optics to a COMSAT Laboratories design.

INDOSTAR uses X-band uplinks and S-band downlinks. These frequencies are allocated for TV broadcasting in Asia.

OSC designed an S-band SSPA engineering model for INDOSTAR; the power FET devices were bought from the Far East. In 1995 when the required number of high reliability devices for flight use could not be obtained due to manufacturing problems (power slump) at the supplier, OSC was forced to use TWTAs.

OSC sees geosynchronous litesats as an important growth area. Multiple litesats can occupy a single orbital slot. Building and launching one at a time allows the satellite operator to begin receiving revenue after a smaller up-front investment. OSC sees older Hughes designs as its principal competition in this market.

OSC is looking at other applications for GEO litesats besides communications.


Except for INDOSTAR, few of OSC's satellites have been designed for communications. In part the company was able to keep its satellites small and low cost by sending minimal data to the ground. Transmission was usually at low speed using in-house VHF or UFH hardware. Recent requirements for higher rates have been met by going to COTS equipment at S-band and X-band.

Communications technology has not been a major emphasis, but recent strategy has been to move in that direction and to focus on payloads. OSC designed the small constellation communications system used in Desert Storm. Comprised of five small LEOs, OSC representatives state that to the best of their knowledge, it is the first of its kind.


OSC is an excellent designer and manufacturer of small satellites. It seems to be skillfully exploiting this market niche and leveraging it to build new products like INDOSTAR.

Published: December 1998; WTEC Hyper-Librarian