This is planetary radio. Hi everyone I'm Mad Kaplan. Nothing is inconsequential as a cold could keep us from bringing you this week's show with lots in store.

Remember Deep Space One?

The testbed spacecraft with the ion engine and 11 other leading edge technologies?

We'll talk to Project Director Mark Raymond about an award he and the DS1 team have just received.

We'll get another quick update from SETI at home chief scientist Dan Werthheimer just back from the

Eresebo dish and on a special what's up you'll hear the funniest entries in our first message

from E.T. contest. Are you ready for a survivor, the Mars Edition?

Emily says there's still a few problems to solve before that live, Prime Time Special. Hi, I'm Emily Loch D'Ala with questions and answers.

A listener asked, considering that satellites are used on Earth to transmit TV signals,

why can't spacecraft, like Cassini, Galileo, or the Mars Orbiters and Rovers send back video instead of still images only.

A Mars video feed would be very exciting, but it is not yet possible.

The main obstacle to receiving video from other planets is that the speed at which data can be sent

over such large distances is very limited.

The distance between the Earth and Mars is always at least 70 million kilometers,

thousands of times the distance between a communications satellite and the Earth.

Over these great distances, the radio signal produced by a Mars orbiting spacecraft is very weak.

NASA is currently building an orbiting spacecraft called Mars Reconnaissance Orbiter that will have the largest

data return of any Mars mission so far.

It will achieve about 4 million bits per second.

By comparison, an ordinary television signal has a data rate of about 30 million bits per second.

The video that we really want to see is from the surface of Mars. For example, we'd really like to watch a Mars rover interact with its environment.

However, the data return rate from Mars's surface is only 100,000 bits per second,

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