These are the traditional frequencies used by the US astronauts. There was reportedly a plan to convert to digital radios in the 400 MHz range. I don't know if this ever happened. Several years back, I was able to listen to an EVA from a shuttle overflight on these frequencies. I used a discone antenna with preamplifier and an ICOM R-9000 receiver. The signal was very weak with that setup. I beleive I was able to hear analog subcarrier telemetry from a heart monitor in the suit.

Frequency Mode Description 296.8000 AM Air To Ground, or Orbiter to Suit 259.7000 AM Air To Ground, or Suit to Orbiter 279.0000 AM Suit to Orbiter, or Suit to Suit 243.0000 AM Military Aircraft Emergency Frequency