Historical Technology Overview


Tension Measurement System

Invocon designed and developed a data acquisition system as an experimental tool to evaluate the performance of nylon dispersion bridles of a parafoil under transient loads, specifically to be used in parachute drop tests for the X38 vehicle preliminary flight tests. The X38 was under development to replace the three-seat Soyuz as a seven-person emergency escape vehicle for the International Space Station (ISS). The Tension Measurement System (TMS) data acquisition units measured tension on the dispersion bridles and ambient temperature data on the parafoil structure.

Sophisticated firmware, combined with a user-friendly PC interface, allowed easy installation, programming, and downloading of data from each unit. Each unit operated on low power consumption, which enabled 5 to 6 data acquisition cycles per battery. Data from all units was time tagged, allowing the information gathered to be used to reconstruct the exact impulse response on the dispersion bridles for the entire parafoil.

The Tension Measurement System was been utilized by the NASA X-38 project to make the first-ever load distribution measurements on a large-scale parafoil system during opening and free flight. The insight provided by TMS riser and leading edge load measurement has allowed NASA and Pioneer aerospace engineers to reduce the number of full-scale drops required to refine and qualify the X-38 parafoil system. NASA extended TMS data utilization to include extraction of aerodynamic coefficients and flight attitude histories from the X-38 parafoil system during parafoil flight and landing flares.


  • Sample Rate: Programmable 10Hz and 50Hz
  • 1 channel per unit
  • The units can support any resistive sensor type
  • Approximate Size: 7cm x 5cm x 4cm