Dragon Returns to Earth after a Month Long Stay at the ISS

^Above photo was from earlier mission.

By Kai Farrimond.

SpaceX’s twelfth Commercial Resupply Mission to the ISS officially ended at 10:14am ET, or 2:14pm UTC on Sunday.  The splashdown of Dragon ended a month-long mission which delivered over 2,910kg of supplies to the orbiting laboratory. Over its time at the station, the vehicle was unloaded of all the science and supplies Dragon launched with on August 14th before being packed with 1720kg of return cargo for Earth, and the hatches between the capsule and the station were closed.

Dragon’s Return

The Expedition 52/53 Crew had spent the last 30 days unloading capsule containing pressurised cargo, and the trunk carrying un-pressurised cargo (This mission consisting of the Cosmic-Ray Energetics and Mass or CREAM).

The splashdown of this mission marks the last landing of a new-build Dragon as all future Dragon 1 capsules will be ones that have been previously flown, like the previous CRS-11 mission in June/July.

On the Friday, the SSRMS or Canadarm-2 once again attached onto Dragon in preparation for it’s un-berthing.

 

Crews then closed the hatches between Dragon and the Station and at around 10:20pm UTC, the the latches were released that had secured Dragon firmly to the ISS for the duration of its mission. Canadarm then rotated Dragon into its release position. It arrived at this position on early-Sunday UTC. Dragon is taken to a point 10 meters away from the ISS where Dragon can safely fire its Draco thrusters to take it away from the station and eventually perform the de-orbit burn.

When the time came for release, at 8:40am UTC on Sunday, 17th September, astronauts Paolo Nespoli and Randy Bresnik gave the command to the Latching End Effector (LEE) to open the snares, releasing Dragon for its trip back to Earth.

Dragon then held its position as the SSRMS backed off to a safe distance from Dragon. Once this distance was released, Dragon conducted a series of departure burns that translated the vehicle away from the station.

Once Dragon was around 1km away from the station, SpaceX took control of Dragon in Hawthorne, California.

Around 5 hours later, Dragon was much further away from the station and it’s GNC Bay Door was closed. The door contains optical sensors, laser-based range sensors and inertial sensors. It also contains the grapple fixture that Canadarm was just attached to.

Dragon then began the 10-minute burn of its Draco engines to put the spacecraft’s trajectory into Earth’s atmosphere and towards the Pacific Ocean.

Following this burn, Dragon separated from it’s trunk which had held the external payloads and the solar arrays. This section will not survive the entry into Earth’s atmosphere as planned. Dragon then rotated to the retrograde position and hit what is known as Entry Interface. This is when Dragon meets the Earth’s atmosphere and starts to encounter the super-heated plasma that heats up the exterior of the vehicle.

Once travelling at a suitable speed and altitude, Dragon’s drogue parachutes deployed, stabilising and slowing down the vehicle to a stage where the main parachutes can deploy. The mains deployed shortly after and splashdown occurred at 14:14 UTC.

Three recovery ships will now locate Dragon and bring it on-board, before sailing in to the Port of Los Angeles and then shipped to Texas for Cargo-Unload. The science will then be sent to labs all over the US for further analysis.

Up Next 

Next up for SpaceX is the SES-11/Echostar 105 mission from LC-39A currently targeted for October 2nd. However there is talk that the T-0 could be delayed to October 7th. This is rumoured to be the final launch from 39A before it gets deactivated for its conversion to support the first Falcon Heavy launch in November. Following 39A’s temporary deactivation, SLC-40 will be reactivated following completion of repairs after the AMOS-6 Explosion in September 2016.

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