High-Precision Deployable Masts


Researchers and collaborators

Olive Stohlman
Sergio Pellegrino
Yunjin Kim (JPL)
S. Case Bradford (JPL)


              The NuSTAR X-ray observatory. Illustration by NASA

              The NuSTAR X-ray observatory. Illustration by NASA

Deployable masts are used in space for a variety of applications, including the deployment of the International Space Station's solar panels and to maintain the baseline antenna separation for the Shuttle Radar Topography Mission. These masts have been as long as 60 meters, while fitting into conventional launch shrouds. Masts composed of long jointed trusses are an enabling technology for telescopes and other sensors requiring very long baselines or focal lengths. An x-ray telescope may need to have its optics held 10 meters away from its detector, requiring accuracy of a millimeter and knowledge of the position to microns. The upcoming NuSTAR mission uses hardware with requirements of this order. In the future, applications will demand greater and greater precision and predictability of the deployed mast shape.

We investigate the limit of precision for this family of structure using finite element modeling. Measurements of actual mast parts are used to build a model in the simulation software Abaqus, which is validated against performance of the whole sample mast in the lab. This validated model is then used to make statistical predictions about the performance of a mast in space. The sensitivity of a modeled mast's performance can also be related to the properties of its individual pieces and subsystems, informing future designs

Related links:

NuSTAR project page (Caltech)
SRTM (External link to NASA)


  • Stohlman, O. R., and Pellegrino, S. (2010) Shape accuracy of a joint-dominated deployable mast. 51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 12-15 April 2010, Orlando, FL, AIAA-2010-2605.