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SpaceX Cargo Capsule Leaves Space Station For Home
An anonymous reader writes "The commercial cargo ship Dragon left the International Space Station, and is heading home with nearly two tons of science experiments and old equipment. From the article: 'The unpiloted Dragon departed the International Space Station at 9:26 a.m. EDT to begin a trip expected to culminate just after 3 p.m. with a parachute-assisted splashdown in the Pacific Ocean, about 300 miles west of Baja California. NASA astronaut and station commander Steve Swanson controlled a 58-foot robotic arm that pulled the Dragon from its Harmony node port at 8 a.m., then released the capsule into space 266 miles over the ocean south of Australia.'"
Splashdown. Status below -
http://spaceflightnow.com/falc...
It could be worse, it could be Monday.
Shut up.
Also, they say the capsule is 12 feet in diameter. I would prefer to know the circumference area in micro-hectares.
The space shuttle was $450 million per mission not including development costs. That would lift 24 ton and a lot of volume to ISS. That was good for building the space station but perhaps overkill for the maintenance. They are not even using the full capability of the Dragon spacecraft.
The Dragon will only move 3.3 ton to the ISS. If you only count weight by dollar this is more expensive than a Space Shuttle launch. On the other hand you will get much more frequent deliveries which may be what is needed now.
If you count development costs, each Space Shuttle launch was 1.5 billion USD. Viewed this way, the CRS program for Space X is just one shuttle. And perhaps this is the correct way to do the accounting considering that the 1.6 billion that Space X receives also has to cover their development costs. I would expect that they can give a good discount on future launches, should NASA want more than 12.
Should be noted that the capsule was physically full. It could have carried more mass but the average density of the cargo isn't that high so it would seem that it could've taken more up while in fact it took a full load.
When resupplying the ISS, it is not all about up/downmass. Physical dimensions also matter and some cargo is lighter than others.
A pound is a unit of weight and can correspond to any kg mass, determined by the gravity of the place where it is being measured.
Weight is dependent on gravity, mass is not. Welcome to 5th grade science class
Which is why the metric system has separate units for mass and weight/force.
But that's not the case with the pound, it is used for both (sometimes, but not always more specifically as pound-force or pound-mass)
http://en.wikipedia.org/wiki/P...
The pound or pound-mass (abbreviations: lb, lbm, lbm, [1]) is a unit of mass used in the imperial, United States customary and other systems of measurement. A number of different definitions have been used, the most common today being the international avoirdupois pound which is legally defined as exactly 0.45359237 kilograms, and which is divided into 16 avoirdupois ounces.
Don't believe Wikipedia? How about the NIST?
http://physics.nist.gov/Pubs/S...
MASS and MOMENT OF INERTIA: To convert from pound (avoirdupois) (lb) to kilogram (kg)
http://physics.nist.gov/Pubs/S...
FORCE: To convert from pound-force (lbf) to newton (N)
The real world is not always as simple as what you learned in 5th grade science, when your teacher said "The pound is a unit of weight, not mass", he was correct and incorrect at the same time due to the ambiguous nature of the unit.