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Dragon arrived at the orbiting station early Wednesday morning

SpaceX's Dragon capsule successfully made it to the International Space Station (ISS) early this morning, where it will unload nearly 1,000 pounds of cargo for the next few weeks.

The unmanned Dragon capsule set off toward the ISS Sunday night, and arrived at the orbiting station early Wednesday morning. Astronauts on the ISS used a robot arm to securely latch the Dragon to the space station about 250 miles above the Pacific, just west of Baja California. 

"Looks like we've tamed the Dragon," said Sunita Williams, ISS commander. "We're happy she's on board with us." 

The Dragon's hatch will be opened tomorrow, where astronauts will begin unloading the cargo inside. Right now, Dragon contains 882 pounds of scientific experiments, groceries, clothes and other items. The capsule will return to Earth with twice as much cargo.

This week's venture to the ISS marks Dragon's second journey to the ISS. It originally made a test flight back in May of this year, but this particular trip marks the first official cargo run as part of a $1.6 billion contract with NASA. This contract locks SpaceX in to 12 total cargo runs to the ISS through 2015. 


While today's linkup at the ISS was a successful one, the entire trip wasn't perfect. A prototype communications satellite aboard SpaceX's Falcon 9 rocket (which launched Dragon to the ISS) was sent into the wrong orbit due to one of the Falcon 9s' Merlin engines shutting down early during Sunday night's launch. Orbcomm, the company that owns the prototype OG2 satellite, said it was "deposited into a lower-than-intended orbit." The company is now analyzing whether the satellite can use its onboard propulsion system to adjust its orbit.

Aside from that malfunction, all went well for the SpaceX mission. Dragon is due to return to Earth near the end of October, after all cargo is unloaded and reloaded. 

SpaceX, a private space transport company from California, stepped in as America's new form of transportation to the ISS after NASA retired its space shuttle fleet throughout 2011. This retirement left American astronauts with no way to get to the ISS, except onboard a Russian Soyuz rocket -- which has become pretty pricey. 

It was clear that the U.S. needed a new way to send supplies to and from the ISS, and SpaceX was happy to provide its Dragon capsule and Falcon 9 rocket. 

Dragon is set to make its next cargo run for the NASA contact in January 2013. 

SpaceX is also working on a Dragon capsule that can be manned by astronauts, and hopes to send the first manned Dragon to the ISS between 2015 and 2017. 

Sources: Boston.com, Reuters



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Two Payloads?
By Terminator64 on 10/10/2012 2:37:17 PM , Rating: 2
By the report, did they have two payloads - the com satellite and the payload going to the ISS? Doing two jobs with one launch is impressive.




RE: Two Payloads?
By geddarkstorm on 10/10/2012 2:50:11 PM , Rating: 2
They did, the satellite was a secondary payload. From the reports I'm reading now, it looks like the reason for the lower orbit was the release of the satellite was on a timer. When the 9th engine was shut down due to a pressure drop, the rocket was slowed just enough that the timer initiated the release of the satellite too early. If so, that timing computer is something they'll need to look at, and build in dynamic features for such engine failure related time to orbit changes.


RE: Two Payloads?
By m51 on 10/10/2012 4:29:02 PM , Rating: 2
Not correct. Read my post above.
The early engine 1 shutdown resulted in lower performance due to gravity losses. This necessitated an extended burn on the 2nd stage to make up the velocity. This left the remaining propellant in the 2nd stage below safety parameters set by NASA based on their Monte Carlo analysis before the flight to achieve an orbit sufficiently far enough away from the space station. The 2nd stage was not re-ignited because the health check on the 2nd stage (attitude,orbit, fuel remaining, etc) were outside the predetermined safety window to reach the orbit intended. An orbital recalc on the fly would not be allowed by NASA when ISS safety is concerned.

The 2nd stage was not re-ignited due to a predetermined decision process, it was not due to a hardware problem with the second stage.


RE: Two Payloads?
By Ringold on 10/10/2012 5:06:27 PM , Rating: 2
That actually paints a better picture then what I imagined; a whole second hardware failure on the 2nd stage on top of the big one on the first stage. Thanks for the clarification!


RE: Two Payloads?
By geddarkstorm on 10/11/2012 1:09:19 PM , Rating: 2
That sounds pretty plausible. There's been a number of different reports that have come out, but yours sounds the most accurate that brings the others together.


RE: Two Payloads?
By kwrzesien on 10/10/2012 2:51:22 PM , Rating: 2
Yes, the OrbComm was the secondary payload. We need to hear more about it's status as it sounds like it might not be a total loss.


RE: Two Payloads?
By DanNeely on 10/10/2012 3:45:03 PM , Rating: 2
Secondary payloads are actually fairly common. You can't finely tune the lift capacity of a rocket; adding additional payloads is a standard procedure to get the most of the sticker price.

For ISS supply runs, the Dragon capsule is much more likely to max out on volume than max. This flight carried ~1000 lbs of supplies and another 1000 lbs of packing material in the Dragon. The first mission carried a similar amount of cargo; but I haven't seen numbers for the packing material. If carrying denser cargo, Dragon can carry up to 7300 lbs to the ISS.

This left ~2.5 tons of free payload capacity within the Falcon's payload area; plenty to add a small satellite as well; it's possible volume limits or the need to additional burns to place the satellite in it's orbit will limit the maximum practical secondary payload to a significantly smaller amount. Orbcom's test satellite was only 330lbs; this could be due to the potential limits suggested above, or just an artifact of no one else wanting to risk a high value payload on a rocket with a very limited history.


RE: Two Payloads?
By m51 on 10/10/2012 8:54:49 PM , Rating: 2
I believe there were actually 3 secondary payloads besides the Dragon spacecraft going to ISS.

Besides the Orbcomm satellite there were a couple of small CubeSats.


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