The recent reports revealed that, the SpaceX Dragon spacecraft has ended its successful mission to the International Space Station (ISS) with the return to Earth this Saturday. The End of Mission (EOM) events started with an unberthing and the release of the CRS-4/SpX-4 spacecraft from the orbital outpost, in front of a parachute-assisted splashdown in the Pacific Ocean at around 15:38 Eastern.
The SpaceX’s Falcon 9 v1.1 launch vehicle, Dragon, Launched early on Sunday, 21st September has enjoyed another successful stay at the International Space Station (ISS).
However, this is the 5th time when the commercial vehicle with the aims of becoming crew-rated into an advanced version known as Dragon V2 or simply Dragon 2 has paid a visit to the ISS.
The Dragon was vigilantly translated towards its orbital on the Earth facing port of the Harmony module as captured by the Canada’s Space Station Remote Manipulator System (SSRMS).
Dragon, riding uphill was a cargo compliment of almost 5,000 pounds of supplies and experiments to the ISS during a month-long stay.The Dragon also contains 20 mice have now taken up residency on the orbital outpost.
The “Mousetronauts” rode uphill in a new hardware system designed to carry rodents safely from Earth to the orbiting laboratory and provide long-term accommodation aboard the station. The rodent research system allows researchers to study the long-term effects of micro-gravity on mammalian physiology.
The Dragon also carried food items, clothing, equipment, experiments and supplies to the ISS along with a 3D printer and new EMU batteries that have since been used on the two recent US spacewalks.
The International Space Station crew removed and stored the cargo, before refilling Dragon with downmass. Since the retirement of the Space Shuttle fleet, Dragon is the only American vehicle capable of returning downmass.
The Dragon also provided the Station with a freight that was launched in her Trunk section.
Known as the ISS-RapidScat, the experiment was attached on the end of the Station’s Columbus laboratory, via the use of the Station’s robotic assets that are now well-versed in removing and installing hardware from the Dragon’s trunk. Canada’s space robot, Dextre (SPDM) removed these freights from the Dragon’s Trunk.
The Space Station Remote Manipulator System (SSRMS) took the firm hold of the Dragon, which arrived back in the location of the spacecraft, following its role with Dextre and the Trunk payload removal tasks.
As the SSRMS holds on to the Dragon – and the bolts released through the opposite process, that saw first and second stage capture – the International Space Station crew will used the “big arm” to pull Dragon away from the port, controlled from the Robotic Workstation (RWS) in the panoramic-viewed Cupola.
Dragon was then planned to let go of the position about 30 feet below the ISS. After releasing from the position, the Dragon and the ISS part ways, via a wring of the trigger on the Rotational Hand Controller (RHC) on the Robotic Workstation.
This was begun by the release of the traps holding the SSRMS Latching End Effector (LEE) to the Dragon Flight Releasable Grapple Fixture (FRGF) – effectively “letting go” of the Dragon.
This process concluded with a 09:56 Eastern release of SpaceX’s Dragon.
With the SSRMS withdrawn securely clear of the spacecraft, Dragon then conducted three departure burns to depart to the vicinity of the ISS, edging away from the orbital outpost, with small thruster firings to push down the R-Bar.
This exodus towards the edge of the ISS’ neighborhood will be monitored by the COTS UHF Communication Unit (CUCU) Crew Command Panel (CCP).
The third burn will be the larger of the firings, which will send Dragon outside of the approach ellipsoid, at which point SpaceX controllers inside MCC-X at SpaceX’s Californian facility will take full control of the mission.
Dragon then enjoyed a free-flying phase on-orbit for around five hours, during which time it completed a critical action – closure of the GNC bay door, to which the FRGF is mounted – before conducting the de-orbit burn at 14:43 Eastern.
The spacecraft’s Draco thrusters was conducting the 10 minute deorbit burn. The umbilical between Dragon and her Trunk then disengaged, preceding the Trunk separating from the Dragon capsule.
As the spacecraft moved into Entry Interface (EI,) it was protected by the PICA-X heat shield. It’s a Thermal Protection System (TPS) based on a proprietary variant of NASA’s phenolic impregnated carbon ablator (PICA) material, which is specifically designed to protect the capsule during Earth atmospheric re-entry, and is even vigorous to protect Dragon from the higher return velocities from Lunar and Martian destinations.
After achieving the required velocity and altitude, Dragon’s drogue parachutes deployed, followed by Dragon’s main parachutes, easing the vehicle to a splashdown in the Pacific Ocean off the coast of California at around 15:38 Eastern.
Soon after the splashdown, 3 main recovery boats arrived on station, with fast boats racing to meet the Dragon shortly after it hit the water, enabling for the recovery procedures to initiate.
Dragon will be transported to the port of Los Angeles, before a trip to Texas for cargo removal.