RTX2010 (Ofer Abarbanel online library)

The RTX2010 manufactured by Intersil is a radiation hardened stack machine microprocessor which has been used in numerous spacecraft.


It is a two-stack machine, each stack 256 words deep, that supports direct execution of Forth. Subroutine calls and returns only take one processor cycle and it also has a very low and consistent interrupt latency of only four processor cycles, which lends it well to realtime applications.


In 1983, Chuck Moore implemented a processor for his programming language Forth as a gate array. As Forth can be considered a dual stack virtual machine, he made the processor, Novix N4000, as a dual-stack machine. In 1988, an improved processor was sold to Harris Semiconductor, who marketed it for space applications as the RTX2000.

Example spacecraft that use the RTX2010

  • Advanced Composition Explorer (ACE)
  • NEAR/Shoemaker
  • Rosetta’s lander – Philae


  • “HS-RTX2010RH”. Intersil. Retrieved 2009-02-11.Intersil’s product page.
  • Rash, James. “Space-Related Applications of Forth”. NASA Goddard Space Flight Center. Archived from the original on 2011-02-04.
  • Hand, Tom. “The Harris RTX2000 Microcontroller” (PDF). The Journal of Forth Application and Research. 6(1): 5–13. ISSN 0738-2022. Retrieved 2013-08-12.
  • Koopman, Philip (1989). “4.5 Architecture of the Harris RTX 2000”. Stack Computers: the new wave. Ellis Horwood. ISBN 978-0138379230. Retrieved 2016-04-16.

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Ofer Abarbanel online library

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