iPad Barometric Sensors for the ISS

Name: Don Pettit
Affiliation: NASA
E-mail: donald.r.pettit@nasa.gov
Knowledge Required:
Description: We need an app that uses the ipad built in pressure transducer to measure atmospheric pressure on ISS for use in emergency situations where crew is closing hatches trying to isolate the leaking module and repair the damage before the total pressure get lower than the safe physiological limit (currently at 520mmHg). Currently we use large, 1960's era Russian supplied mechanical barometers, however, they have been unable to supply these anymore so we are down to only two working ones left on orbit. We have perhaps 8 to 10 ipad-air2's on orbit and with the proper app, they could be used in an emergency to guide the crew.
Objectives: 1) find out the operating specifications of pressure range and accuracy for the built-in ipad pressure transducer
2) create a display that clearly shows cabin pressure in mmHg in the range 400 to 850 to nearest 0.1mm (standard cabin pressure runs 730 to 755 mm)
3) have a "start/stop button" that records and displays the initial pressure and starts/stops the plotting function (see #5)
4) continuously show dt/dP in seconds per millimeter (this is based on timing the hand movement on the mechanical gage and using that number in a graph)
5) have a running plot of P vs t updated every 2 seconds
6) record this data and be able to output it in a spreadsheet file readable by excel
7) the front page would show pressure, dt/dP, initial pressure, with start/stop record button, large, using high contrast digits
8) a second page displays the P vs t plot with finger zoom capability
9) a settings page to allow different pressure units, recording times, significant digits on displayed numbers etc.
Other comments: Check out the app store, there are a number of barometer apps that are optimized for weather but not our needs at NASA.

   D. Kevin McGrath
   Last modified: Tue Mar 6 10:29:08 2018