Interview with astronaut Daniel Tani

1-What are the telecommunications means used by space shuttles during the different trips, and specifically what are the frequencies used? For Apollo 11, the late Niels Armstrong told me when we met on the 24^th of November, 1997 in Rabat, Morocco, that the S-Band is used between the moon and the earth (Houston), while the VHF is used between the earth (Cap Canaveral and Houston) and the atmosphere (870 miles). Did the space shuttle use only the VHF band?

The Space Shuttles used VHF, UHF, S-band and Ku-band.  VHF was used as the primary voice communication to the ground.  UHF was the backup radio to the ground.  UHF is also used between space-waking astronauts and the shuttle (or ISS)  S-band was used by Mission control to send commands to the Shuttle and to receive data (telemetry) from the Shuttle.  Ku was used to send high-rate data to the ground – usually video or computer files.  The ISS only uses S-band and Ku-band.

The different telecommunications systems used aboard the International Space Station This photo is added by M.A. Khaouja

2- As an astronaut, how many space trips have you made and what was the total time you spent in space?

I took 3 trips to space: the first on STS-108 on Endaevour in 2001.  My second trip consisted of launching on STS-120 on Discovery, living on the International Space Station (ISS) and then coming home on STS-122 on Atlantis.  My total time in space is 132 days.

3-What were the most interesting scientific experiments you carried out aboard the International Space Station?

One experiment we did was missing 2 fluids of different densities (think of oil and vinegar salad dressing).  On Earth, after you mix them, gravity will pull the heavier (vinegar) towards the ground and they will separate.  In space without gravitational forces, they will not separate.  However, this experiment looked at what happens after a long period of time (weeks).  It turns out that the same-density particles attract each other and clump together – but the forces are so small that we could never observe them with the presence of a high bigger force – gravity.

4- What does space look like from the International Space Station?

Looking out into space from the ISS is very similar to looking at space on a dark cold night from the Earth.  Since we are no closer to the stars or planets (the ISS is only 400 km above the Earth’s surface), the stars and planets do not look any bigger.  Since we are not looking through atmosphere, we can see dimmer stars and so many more stars are visible, but it is not a much different view than from Earth.