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SpaceX CRS-4 has LAUNCHED! Docking with ISS on Tuesday (23rd)


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I have a question that may seem rather basic, but for the life of me I can't seem to figure out. How is it going to take until Tuesday morning for the ship to intercept the ISS? I can understand maneuvering once it gets close to the station. I know a lot of my understanding of the complex workings of orbital physics is from a game where everything's in small scale, but two days from circularizing to approaching the ISS seems like a hell of a time.

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the camera view from inside the second stage tank when the second stage cut off is great :) (and shows why ullage is required to restart a stage :P)

http://gfycat.com/HelpfulScholarlyIggypops

I loved that view! Was that that LOX or RP-1?

I have a question that may seem rather basic, but for the life of me I can't seem to figure out. How is it going to take until Tuesday morning for the ship to intercept the ISS? I can understand maneuvering once it gets close to the station. I know a lot of my understanding of the complex workings of orbital physics is from a game where everything's in small scale, but two days from circularizing to approaching the ISS seems like a hell of a time.

We're far too agressive with our approaches in KSP. I'm guilty of launching and then circularizing at less than 1 km from the station, leading to some crazy things like 20 minutes from launch to docking. In real life, ships don't have the kind of maneuverability ours have, so they have to take a very slow approach and correct it little by little. It's boring, but it gets the job done. :)

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I have a question that may seem rather basic, but for the life of me I can't seem to figure out. How is it going to take until Tuesday morning for the ship to intercept the ISS? I can understand maneuvering once it gets close to the station. I know a lot of my understanding of the complex workings of orbital physics is from a game where everything's in small scale, but two days from circularizing to approaching the ISS seems like a hell of a time.

First of all, you have to realize that the ISS is in an inclined orbit. So you can only launch in the correct orbital plane twice a day. Those are your launch windows. If you launch outside your launch window you end up in an orbit that has a very big inclination to the ISS's orbit and it would be too expensive on the dV budget to ever fix it. Therefore you can't time your launch so you have a nice and quick rendezvouz.

Sometimes the ISS is on the other side of the planet after your launch. So you need to either be in a higher orbit so the ISS catches up to you, or a lower orbit so you catch up to the ISS. In real life they always use a lower orbit because this is cheaper dV wise, so you can haul more stuff to the ISS. This catching up takes a lot of time though. The ISS orbits at 350km and a typical parking orbit is something like 200km. Some simple math shows that the difference in orbital period is only about 3 minutes. So if you are unlucky and you ended up right in front of the ISS you'll have to orbit around the planet about 30 times before you catch up to it. At 1.5 hours an orbit this takes you nearly 2 days.

It gets even worse later on because you aren't allowed to fire the main engines near the ISS so as to avoid contamination of the sensitive instruments. So when you get close you have to raise your orbit and close the gap very gently. This can easily take another day.

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I understand that this launch included live animal cargo. Specifically, about 15 mice.

What I find myself wondering is how they stowed the live animal payloads on board so that they could survive the launch and two days abroad Dragon before they get to the ISS? Presumably they didn't just load a cage full of mice, wood chips and all. But they also wouldn't have made little mouse space suits and custom fit couches...

Presumably the experiment would need to meet standards for ethical treatment of animals. How would they have restrained the mice so they could survive the ride to orbit without injury? What about access to food and water? I am envisioning something along the lines of little mouse sleeping bags to restrain them from floating away from their food and water source during the two day trip.

But maybe I am totally off? Does anybody know the details?

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I understand that this launch included live animal cargo. Specifically, about 15 mice.

What I find myself wondering is how they stowed the live animal payloads on board so that they could survive the launch and two days abroad Dragon before they get to the ISS? Presumably they didn't just load a cage full of mice, wood chips and all. But they also wouldn't have made little mouse space suits and custom fit couches...

Presumably the experiment would need to meet standards for ethical treatment of animals. How would they have restrained the mice so they could survive the ride to orbit without injury? What about access to food and water? I am envisioning something along the lines of little mouse sleeping bags to restrain them from floating away from their food and water source during the two day trip.

But maybe I am totally off? Does anybody know the details?

Here's an article describing the life support systems for the mice:

http://www.space.com/27200-spacex-dragon-launch-mice-3d-printer.html

As far as the ethics, I assume they fall under the same ground as any other lab mice on Earth.

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Yeah, there's not much infos on how they protect the mouses against vibrations / g-forces during the launch (and then release them if they are attached so they can drink and eat during the two days needed for them to reach ISS)

Here 's another article on the rodents habitat.

http://www.gizmag.com/rodent-residence/32219/

Edit :

Here's detailed infos on the AEM habitat they used for mices / rats on the space shuttle - i guess the current version is almost the same (except they have a system for using multiple modules i guess)

http://gravitationalandspacebiology.org/index.php/journal/article/viewFile/606/628

Edited by sgt_flyer
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As I understand the unmanned dragon has some life support system however its not designed for humans just to keep pressure and oxygen level from stuff like oxidizing.

Remember its also designed for long term experiments, either independent or including IIS docking, stuff who require absolute zero-g and no vibrations like crystal growth is better done in an small free flying pod.

It might just be an bottle of pressurized air but should be more than enough for the mouses in 2 days.

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