Hooke's Law Orbital Motion

A reduced-gravity physics experiment
flown aboard the "Weightless Wonder"
5-6 August 2010

This experiment explored the behavior of two masses, connected by a spring and set into rotation in simulated zero gravity, resulting in orbital motion. The experimental apparatus consists of a custom-built turntable that accelerates a mass-spring-mass system to a predetermined angular speed before releasing it during a zero-g interval. A high-speed video camera recorded each run, allowing frame-by-frame analysis of the masses’ trajectories.

Team Members: Jeff Regester, Chris Bernhardt, Jason Cheek, Melinda Graham, Tim Martin, Eric Shilling

NASA/JSC mentor: Fiona Turett


WFMY coverage 28 July 2010 (external link; video in right margin)
End-of-Flight-Week video by Eric Shilling (high-res version)
NASA videographer footage, including stock footage, test readiness review, and the flights
Newton's Laws Demonstration video of masses without rotation


Best Photos from construction, testing, and flight week
Apparatus Construction
Pro Photos taken by NASA photographers during flight week


Test Equipment Data Package: flight safety analysis document
BS2 code: detects IR signal from remote, activates trip servo
Motor Test Data: used to determine the correlation between drive voltage and RPM of the turntable.


Abstract, briefly describing the experiment
Experiment description from the RGFWO application
News & Record article, postflight


Postflight presentation (pptx, 10 MB)
Postflight, short version (pptx, 5 MB)


Excerpt from Mullane, Riding Rockets, The Outrageous Tales of a Space Shuttle Astronaut

HLOM flight team

RGO logo


The materials on this site may be used by anyone for non-commercial, educational purposes. We would appreciate a note letting us know what you used the materials for.
(Send to jregester@greensboroday.org.)

NUMERICAL MODELS constructed in Microsoft Excel

sim4b: Incorporates all of the below features, but also takes into account the physical size of the masses. Uses VBA to control animation.
sim3: Runge-Kutta second-order integration; plots trajectories, energies, angular momentum, angular velocity. Input cells are in green. On the plots, masses A and B are color-coded in red and blue, respectively. Light red and light blue denotes when the spring is in compression and thus liable to buckle. Actual buckling is not modeled. The spring is massless, and the masses are points.


Newton's Laws Demonstration video of masses without rotation
Hooke's Law Orbital Motion Lab (v3b) for AP Physics (Jeff Regester)***
Tracker open-source video analysis software
Newton's 2nd Law inquiry lab for middle schoolers (Tim Martin)***
Accelerometer data from Flight 1
Aircraft Track data from Flight 2

***Internet Explorer 8 sometimes has a glitch when downloading these docx files. Use a different browser to download these.

DATA ARCHIVE    See further info at the bottom of the table.

  Flight Run Configuration* target RPMo** Video (raw) Video (analyzed)
  1 2 B3B 10-10 23 .mov  
  1 3 B3B 10-10 120 .mov  
  1 6 C9D 10-20 63 .mov  
  1 7 C9D 10-20 28 .mov  
  1 8 C9D 10-20 20 .mov  
  1 9 C3D 8-12 39 .mov  
  1 12 B4B 16-16 161 .mov  
  1 14 B4B 16-16 85 .mov  
  1 15 B4B 16-16 77 .mov  
  2 1 A10C 4-20 78 .mov  
  2 2 A10C 4-20 50 .mov  
  2 3 A10C 10-10 66 .mov  
  2 4 A3B 8-16 51 .mov  
  2 5 A3B 10-20 51 .mov  
  2 6 A3B 10-20 34 .mov .mp4
  2 7 A3B 10-20 24 .mov  
  2 8 A3B 24-24 0 .mov  
No rotation. Great demo of Newton's laws.
  2 9 A3A 24-24 0 .mov  
No rotation. Great demo of Newton's laws.    
  2 10 A3D 24-24 0 .mov  
No rotation. Great demo of Newton's laws.
  2 11 B3B 20-20 71 .mov  
  2 12 B3B 20-20 35 .mov  
  2 13=1b B*10C 4-20 78 .mov  
  2 14=2b B*10C 4-20 50 .mov  
  2 15=3b B*10C 10-10 66 .mov  
  2 16=4b A3B 8-16 51 .mov  
  2 17=5b A3B 10-20 51 .mov  

* Configuration: Mass A is approximately 1 kg (0.991 kg), B = 0.5 kg (0.494 kg), C = 0.2 kg (0.196 kg), D = 0.1 kg (0.094 kg). The number between the letters is the particular spring used; see the spring properties table below.

The two numbers separated by a dash are initial distances of the two masses from the turntable axis, in centimeters.

The center-of-mass-to-hook distances for each each mass are as follows:
A (4.80 cm), B (4.05 cm), C (3.10 cm), and D (3.35 cm).

** In some cases, the planned initial RPM may be dramatically different than the actual initial RPM.

All data video was shot at 300 frames per second.
For scale purposes, the rotating apparatus from which the masses are released is 50.6 cm long.