SpaceX Falcon 9/Dragon CRS-2 SpX-2 MISSION GENERAL DISCUSSION

[joek]

Why only 1200 pounds of upmass? I think I missed why. Seems low.

600kg is as empty as the last resuply flights of the Dragon. The Falcon 9 V1.0 will never show what it can lift. 3000kg lack of performance between the written performance and the shown one is really astonishing. As this is the last launch the numbers should be corrected by SpaceX soon without losing to much credibility. 6,622 kg - 10,454 kg to LEO is more likely like to be 6,622 kg - 7,454 kg.

Do we know if it is mass or volume limited?  Nits: 2760kg not 3000kg difference (CRS calls for max 3310kg upmass/flight).  NLS F9v1.0 payload to ISS (51.6 x 370km) shows as ~8200kg; add payload fairing/adapter(?); subtract dragon and trunk (what's their mass?); what's left for cargo?

[stone]

http://www.nasa.gov/home/hqnews/2013/feb/HQ_M13-029_SpaceX_ISS_Launch_Set.html

SpaceX's Dragon capsule will be filled with about 1,200 pounds of supplies for the space station crew and experiments being conducted aboard the orbiting laboratory.

This is where I got the numbers from.

[QuantumG]

Why don't you ask NASA?

[joek]

http://www.nasa.gov/home/hqnews/2013/feb/HQ_M13-029_SpaceX_ISS_Launch_Set.html

SpaceX's Dragon capsule will be filled with about 1,200 pounds of supplies for the space station crew and experiments being conducted aboard the orbiting laboratory.

This is where I got the numbers from.

Right, so are you saying that "as empty as the last resuply flights of the Dragon" and "3000kg lack of performance" implies that we should be seeing more cargo upmass, and the lack indicates a shortfall in performance?  Maybe it's not "empty" or "lack of performance", but rather it is volume limited and they have stuffed it full of low density cargo ("t-shirts, tang and toilet paper")?

[Robotbeat]

Could be and probably is a combination of factors, including that they're using the v1.0 Falcon 9.

[SpacexULA]

Could be and probably is a combination of factors, including that they're using the v1.0 Falcon 9.

Exactly, Falcon 1.0 is about have it's last flight.  I guess the best way to partially settle the issue is wait for CRS 3 and see if it's pressurized  cargo goes up significantly.

[Robotbeat]

Could be and probably is a combination of factors, including that they're using the v1.0 Falcon 9.

Exactly, Falcon 1.0 is about have it's last flight.  I guess the best way to partially settle the issue is wait for CRS 3 and see if it's pressurized  cargo goes up significantly.

That won't be the end of it, though. Because SpaceX doesn't have any reason to max out the Falcon 9 v1.0 flights, they may choose to do so even if v1.0 could handle significantly more. They may be just buying margin since v1.1 can get almost twice as much to orbit, so could easily pick up all the extra slack with even more margin to spare. SpaceX has no reason to fly v1.0 without tons of margin since their total contract only stipulates a limited amount of cargo to begin with.

[pathfinder_01]

600kg is as empty as the last resuply flights of the Dragon. The Falcon 9 V1.0 will never show what it can lift. 3000kg lack of performance between the written performance and the shown one is really astonishing. As this is the last launch the numbers should be corrected by SpaceX soon without losing to much credibility. 6,622 kg - 10,454 kg to LEO is more likely like to be 6,622 kg - 7,454 kg.

Life support stuff aka the stuff that dragon lifts(food, clothes, ect..) is bulky not heavy. They are probably volume limited not mass limited.

[beancounter]

600kg is as empty as the last resuply flights of the Dragon. The Falcon 9 V1.0 will never show what it can lift. 3000kg lack of performance between the written performance and the shown one is really astonishing. As this is the last launch the numbers should be corrected by SpaceX soon without losing to much credibility. 6,622 kg - 10,454 kg to LEO is more likely like to be 6,622 kg - 7,454 kg.

Why do you believe the stated numbers are incorrect?
NASA decides the payload, not SpaceX.  It seems that NASA isn't interested in using additional payload capacity or perhaps simply doesn't need to at this point.
If you have evidence to the contrary, I'm sure many of us would be interested in it.   

[Galactic Penguin SST]

When did the two cubesats once planned piggy back on this flight got moved to the CASSIOPE flight?

[stone]

Why do you believe the stated numbers are incorrect?

I do not belive in the theoretical numbers as long they have not been proven by an experiment.

The maximum payload for the Falcon 9 v1.0 ever lifted to LEO is 3000 less than what is in the papers.

All other transports to ISS show a much larger load factor more like 50% not the 15% which are standard for Dragon flights.

I hope for the v1.1.

[smoliarm]

...
The maximum payload for the Falcon 9 v1.0 ever lifted to LEO is 3000 less than what is in the papers.
...

This was already discussed here many times, you just forgot to add something. Show the details of your arithmetic and I'll show your mistakes. This Falcon flight do have weight margin, but your number - 3000 - is way too high, check you list

E.g., you definitely forgot packaging, these "1200 lbs" are net cargo.
Here is quote from CRS-1 manifest:
Total Cargo Up Mass .......   882 pounds (400 kilograms)
Total Mass w/Packaging ... 1995 pounds (905 kilograms)

Applying the same proportion to this flight, we have 690kg of packaging on CRS-2.
I just found "missing" 0.7 tonnes out of your 3.0 deficit, may be you'll try to find the rest? (The correct answer for 'under-performance' is about 1 tonne.)

>>beancounter
>>NASA decides the payload, not SpaceX.
I agree, also I would guess that NASA decides on performance margin left, and they do not care about "credibility".
So do I. I just wish them luck and flawless flight

[Ben the Space Brit]

[E.g., you definitely forgot packaging, these "1200 lbs" are net cargo.
Here is quote from CRS-1 manifest:
Total Cargo Up Mass .......   882 pounds (400 kilograms)
Total Mass w/Packaging ... 1995 pounds (905 kilograms)

That's nearly doubled mass from packaging! Are all space supplies so heavily wrapped? 

[MP99]

Nearly?

Cheers, Martin

[smoliarm]

...
That's nearly doubled mass from packaging! ...

nearly

Are all space supplies so heavily wrapped?

Given the price NASA is paying, I would guess that "all space supplies" are wrapped appropriately
 

[Nate_Trost]

Do those figures include the trunk payload?

[Norm38]

Per the CRS-1 processing, we expect the rocket to not roll out to the pad until Friday morning for the 2/22 hotfire test, correct?

[Jim]

That's nearly doubled mass from packaging! Are all space supplies so heavily wrapped? 

Yes, Because they see 5-6gs.

[woods170]

600kg is as empty as the last resuply flights of the Dragon. The Falcon 9 V1.0 will never show what it can lift. 3000kg lack of performance between the written performance and the shown one is really astonishing. As this is the last launch the numbers should be corrected by SpaceX soon without losing to much credibility. 6,622 kg - 10,454 kg to LEO is more likely like to be 6,622 kg - 7,454 kg.

What do we have here? Another member that is under the impression that Falcon 9 v1.0 performs less than the numbers given by SpaceX.
In case you had not noticed; after the little incident on CRS-1 a whole lot of details about that flight were unintentionally released in some of the press-conferences given by NASA. One very interesting tid-bit was that the Falcon 9 for CRS-1 was ballasted, because the cargo load on Dragon was so light. Had Falcon 9 not been ballasted the booster would have over-performed. NASA also unintentionally confirmed back then that they had not required the full payload capacity of CRS-1 from SpaceX AND that the flight was volume limited, not mass-limited.

Just because a booster CAN perform to a certain number does not mean it HAS to perform to that number on any given flight.
Your statement, casting in doubt the performance numbers of Falcon 9 v1.0,  is equal to stating that Ariane 5 ECA must fly 10 metric tons to GTO, on any given flight, otherwise it's performance is not proven. In short: your post is bordering on the ridiculous.

[Antares]

Ballast, as Shuttle showed, has more to do with CG location and control stability (or not having to re-analyze stability after a manifest change) than "overperformance."