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Comment by mixmax | Hacker News Reader

Since there's probably nobody else using the line - nothing.

Or more accurately: The fixed cost for getting the dataline installed is extremely high, but once it's there and has no other use than sending data back to earth it's almost free to use. The only cost is the electricity used, and since it's on a nuclear battery that will run for many years you can discount that.

In other words: Send as much data back as you possibly can. Prioritise it and send the most important first of course, but don't ever let the line sit idle.

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Actually, as the "line" consists of the orbiting satellites acting as relay stations, it is very much shared with the orbiters' own science missions.

Most of the time the link is going to sit idle; an orbiter is only overhead a few times a day, a few minutes at a time. So there will be scheduled bursts of communications. AFAIK the Curiosity-orbiter bandwidth is about 2Mb/s, and the highest-speed orbiter-Earth link is up to 6Mb/s (that of Mars Reconnaissance Orbiter--MRO has returned more data than all other Mars missions combined.)

Curiosity also has two antennae that allow direct communication with the Earth (when it's over the horizon) but they are too slow (hundreds of bits per second) for heavy-duty image downlinking.

2 and 6 Mbit/second is pretty good bandwidth.

It would have been a reasonably good Internet connection if not terrible ping of 1680000 ms (almost half hour).

On the Earth side there may be contention since AFAIK the Deep Space Network is shared by multiple missions.

http://deepspace.jpl.nasa.gov/dsn/

http://en.wikipedia.org/wiki/Deep_Space_Network

If you wanted to estimate value, you could do that based on the fixed cost you mentioned, as well as the ground-side operation and maintenance costs (including salaries).

And assuming you were talking about the market price of using the channel for just anything, add some valuation of the opportunity costs of not using the line for the things NASA will use it for.

edit: why bother saying this? Private industry is entering space, professionals who know something (unlike me) will be very interested in figuring out the value of things NASA has been doing.

How did I miss that this thing was running on nuclear power. I guess I just assumed battery + solar.

Pretty sweet! It can run for a minimum of 14 years. I don't recall the last rovers using nuclear?

http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Rover

the last rovers were solar powered, which is partly why they were dormant in the winter and at night.

I wonder how much more weight/space not having large solar panels gives them for scientific equipment. I assume it's a not-insignificant difference.

Well, sort of. It is not so much about reducing weight or size; the rover weighs 900kg (basically, one US ton). It is about energy budget; with the radioisotope thermoelectric generator, "nuclear battery," there is ample power not only to move such a behemoth around, but also to power some really interesting scientific instruments. For example, the rover has a laser which can vapourize a small sample which can then be analyzed spectrally to get chemical composition. Imagine trying to power a laser like that on solar panels.

In space, in the inner solar system, solar panels are more power dense than RTGs.

The situation might change enough being on planet where the sun is slightly filtered by the thin atmosphere, and the sun doesn't shine ~12 hours a day.

RTGs have many other advantages: they provide heat as well as power (which is really important on Mars) and they don't wear out when covered with dust. If Curiosity stops running within a decade, it won't be because of power.

Sending $$ might not be much. Receiving is another story.

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