SpaceX is a go for April 30th: 1st commercial launch to space station

[RAMA]

http://www.wired.com/autopia/2012/04...space-station/

...and so it begins!

[Dukhat]

I sincerely hope everything goes off without a hitch. I'm a bit worried about the Progress cargo ship launch a few days from now, since it was the crash of the second-to-last Progress that caused one of the worst delays for this Dragon launch.

However, most of the worry stemmed from the possibility that the ISS would have to be abandoned because of lack of supplies, which is what this Dragon mission will be stocking them with anyway. Plus they already have the supplies from ESA's ATV cargo ship.

[sojourner]

^Nope, this dragon mission is a test. There is no required cargo on board, just t-shirts and delicacy consumables that won't be missed if it fails.

[YellowSubmarine]

The cargo is cheap, but it is certainly important cargo, including food and water which is pretty much required. As far as I can tell it's not carrying oxygen, fuel or medical supplies, but I'd guess the last Progress mission carried a few of those that would last for some time.

[sojourner]

^No, it's not important or required. Otherwise they wouldn't risk it on a test mission that has a good possibility of not docking. Like I said, the only thing on that capsule is cargo above and beyond "required". food delicacies and clean shirts. Maybe another wheel of cheese.

[Lindley]

The cargo is certainly not irreplaceable. I don't think that's the same as saying it's not important.

[sojourner]

It's 1200 pounds of material they can live without (and not miss, considering this launch has been delayed almost 5 months) if the capsule is unable to deliver. That's pretty unimportant. It's pure gravy and not needed in any respect.

[Lindley]

There's no such thing as unimportant supplies on the space station. They may not be urgently needed, but getting them up there now certainly would relieve the need to send them up later.

Test or no test, there's no way anyone would waste a launch by failing to send up some supplies.

[sojourner]

Um, no. I think you have the definition of "important" wrong. If something is not needed, it's not important.

The cargo on this mission is not needed, it won't be sent up later on another mission if this one fails. the most you could say about it is it is increasing their stock above the current margins. Its purely a bonus.

If it were "important" it wouldn't be on a test mission that might not make it there.

[Lindley]

Nobody is going to waste valuable cargo capacity on something unimportant, test or no test. Nothing that would be missed if it is lost will be sent. But the $/pound for each launch is too high to waste any opportunity to increase stocks.

[sojourner]

Then, argue me this. why are they not sending up a full load? Because what they are sending is not needed. It's not "important". Nobody said they were wasting the opportunity to send something up. They're just not taking the risk of sending something important.

The important thing about this launch is the mission's success or failure as a test of the system. The cargo is pure after thought and was not required by NASA. SpaceX could have filled the thing with pink plastic flamingos if they had wanted. Hell, the last capsule they sent up for COTS mission 1 had a single wheel of cheese as the cargo.

Since SpaceX did volunteer to put a modest cargo in, I am sure they consulted NASA on what might be handy or what was allowed, but you can rest assured that nothing important is being sent.

Something not needed is by definition not important.

I say we table the discussion until that cargo is revealed in the coming month because this is just becoming silly.

[Lindley]

I think we have different definitions of the term. All I got from the article was that nothing irreplaceable or critical was being trusted to this launch. It says nothing about how important the cargo is.

On a space station, every air exchange filter, every bite of food, every gallon of water is important. It doesn't matter if you have enough already, it's still important to get more when you can, unless you literally cannot store it for later. You never know when a technical problem is going to delay the next resupply flight, especially now that there's only one proven system operational.

[sojourner]

Lindley wrote:

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On a space station, every air exchange filter, every bite of food, every gallon of water is potentially important.

There, fixed that for ya.

It's potentially important should something go wrong with the established system. But right now, being un-manifested and unrequired for normal operation, it's not important.

The word you should be using is "useful". And depending on the details of what they are actually sending, that may not be true either. For all we know it's 1200pounds of deodorizer.

Lindley wrote:

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especially now that there's only one proven system operational.

Which "one" is that? the russian Progress? the ESA ATV? or the Japanese HTV? all of which are proven.

[YellowSubmarine]

If cargo that's not immediately needed is not important then any cargo for the ISS is not important because they stock enough of everything to make sure that a failed launch or two won't kill the astronauts or lead to the abandonment of the station.

But I don't see the purpose of this dictionary debate – the original question was not whether Dragon's cargo will decrease the probability of a supply shortage. A pretty straightforward one. Since the capsule will replenish the food and water supplies on the station, the answer is yes. You're begging the question with these semantics.

[sojourner]

The difference between this mission and others is that the cargo on others is scheduled and manifested. This one is not.

Just trying to illustrate that the point of this mission is not the cargo. It's to successfully test the dragon system. Any cargo delivered is purely an after thought.