SpaceX spacecraft sends crucial science supplies to ISS

NASA's private sector partner Space Exploration Technologies Corporation (SpaceX) has sent its Dragon spacecraft to the International Space Station (ISS) with over two tonnes of supplies and science investigations.

The mission is the California-based company's fifth official cargo delivery flight to the station through NASA's commercial resupply services contract, the US space agency said in a statement.

Dragon's cargo will support more than 250 experiments that will be conducted by the station's Expeditions 42 and 43 crews.

"We are delighted to kick off 2015 with our first commercial cargo launch of the year," said NASA administrator Charles Bolden.

"Thanks to our private sector partners, we have returned space station resupply launches to US soil and are poised to do the same with the transport of our astronauts in the very near future," Bolden added.

The launch not only replenishes supplies to the station but also delivers important science experiments and increases the station's unique capabilities as a platform for Earth science with delivery of the Cloud-Aerosol Transport System (CATS) instrument.

The CATS instrument measures the location, composition and distribution of pollution, dust, smoke, aerosols and other particulates in the atmosphere.

With CATS, scientists can gain a deeper understanding of cloud and aerosol coverage, creating a better model of their role in the Earth's changing global climate.

A new biological study will use flatworms as a model organism to see how gravity affects tissue regeneration and the rebuilding of damaged organs and nerves.

Also making the trip as model organisms will be fruit flies (Drosophila melanogaster).

"Scientists will study the flies' immune systems as a model for the human immune system to explore how spaceflight can make organisms more susceptible to disease, especially since microbes can become more virulent in space," the statement read.