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One Last mission For Deep Space 1
Vertigo01 writes: "Looks like NASA has found a fitting end for Deep Space 1, they're going to fly her THROUGH the coma of a comet to try and take some pictures of the comet's core ... the kicker is that they're doing it with barely any fuel left, and a kludged-together science-camera to replace the toasted navigation system ... kind of a fitting end for her IMO."
It was a good, clean and funny TV show that has made me want to become an engineer.
In order to communicate the probe you need to rent time on the Deep Space Network. This network is currently running at capacity, so getting time on it is rather expensive.
But an even bigger expense is the mission software. Modifications to the programming of the probe need to be codded. Then the code has to be proved to be mathematically perfect. You cannot afford to compile it, upload it, and get a message back saying "stack overflow, press any key to continue". The software must be proven to be 100% bug free before it goes up.
It takes a lot of people to manage a space mission correctly. Cut corners, and your mission fails because of something stupid (e.g. metric vs imperial).
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A comet gives off gas which is fairly tenious and gets blown away more or less directly away from the sun. Its the dust and grit that is the risk, and that gets left behind in the vicinity of the orbital path, in the same region of space where DS1 will be. (same stuff also causes meteor showers when earth orbits accross the dirt trail)
The important thing from DS1's point of view is to keep the relative motion between the coment and the probe as small as possible, both to maximise encounter time and to make it easier to 'aim' the probe and its cameras at the comet. (this also saves fuel, which is a heavy, scarce and precious resourse in outer space)
In effect, the two objects are on almost on a parallel path, at slightly different speeds, not a perpendicular intersection as one would think.
Its like two veichicles on a slowly curving highway, one slowly overtaking the other. If the comet is an open dumpster truck in the slow lane, you will be showered with garbage for miles before you eventually pass it out! (even though you are only 'alongside' it for a few seconds)
-- We don't understand software, and sometimes we don't understand hardware, but we can *see* the blinking lights
But why were there any Imperial units used on-board at all? Slugs and foot/lbs in space?
Conversions using floating point numbers always give me the willies. Case in point: Microsoft DATE class for holding time/date values. It uses a floating point number to hold the value, with the fractional part holding the time. If you add/subtract to convert local time to GMT and back, the number has shifted out about the 8-9th decimal place. As a result, a time comparision with an unshifted number will fail. *shudder*
There's a reason financial calculations should never use floating point.
One line blog. I hear that they're called Twitters now.
The point of the Deep Space series of missions, of which the Mars Polar Lander was #2 and went AWOL, was to test new tech for next to nothing (in NASA terms).
Do any of you realise that DS1, apart from being 8 revs away from the greatest Trek ever, was powered by an ion engine? You know, like Star Wars?
Plus, when the nav system went tits up, they were able to retask other optical instruments to allow for autonomous piloting.
DS1 wasn't even supposed to make it this far. IIRC, it was expected to have a 3-month primary mission to test the equipment. Then, if there was enough gas in the tank and the thing still worked, they were going to find something else for it.
An asteroid flyby and now a comet encounter...not bad for $12 mil!
P.S. I'm a bit biased on this one - I watched the launch and have read every one of the oddball logs posted by Dr. Raymond.
C'mon, NASA, where's DS3?
GTRacer
- Wants to be first at something
Defending IP by destroying access to it? That makes sense, RIAA/MPAA. Go to the corner until you can play nice!
It's unfair to call DS1 a failure just because of early engine and navigation problems. It successfully completed its mission (and then went beyond the call of duty with the landing) and now is just being put to the test again. DS1 was an extremely successful mission, not a "malfunction".