Editing CASSIOPE (section)

===Post-mission launch vehicle testing===
{{main|SpaceX reusable launch system development program}}

After the [[second stage]] separated from the booster stage, SpaceX conducted a novel [[flight test]] where the [[Falcon 9#First stage|booster]] conducted a test to attempt to reenter the lower atmosphere in a controlled manner and decelerate to a simulated over-water landing.<ref name=nsw20130328>{{cite news |url=http://www.newspacewatch.com/articles/spacex-moving-quickly-towards-fly-back-first-stage.html |title=SpaceX moving quickly towards fly-back first stage |work=NewSpace Watch |first=Clark |last=Lindsey |date=March 28, 2013 |access-date=March 29, 2013 |archive-url=https://web.archive.org/web/20130416030256/http://www.newspacewatch.com/articles/spacex-moving-quickly-towards-fly-back-first-stage.html |archive-date=April 16, 2013}}</ref>  The test was successful, but the booster stage was not recovered.

After the three-minute boost phase of September 29, 2013 launch, the booster stage [[Spacecraft attitude control|attitude]] was reversed, and three of the nine engines refired at high altitude, as planned, to initiate the deceleration and controlled descent trajectory to the surface of the ocean. The first phase of the test worked well and the first stage [[Atmospheric reentry|re-entered safely]].<ref name=pa20130930>{{cite news |url=http://www.parabolicarc.com/2013/09/29/falcon-9-launch-payloads-orbit-vandenberg/ |title=Falcon 9 Launches Payloads into Orbit From Vandenberg |work=Parabolic Arc |first=Doug |last=Messier |date=September 29, 2013 |access-date=September 30, 2013}}</ref>

However, the first stage began to roll due to aerodynamic forces during the descent through the [[Stratosphere|atmosphere]], and the roll rate exceeded the capabilities of the booster [[attitude control system]] (ACS) to null it out. The fuel in the tanks centrifuged to the outside of the tank and the single engine involved in the low-altitude deceleration maneuver shut down.  Debris from the first stage was subsequently retrieved from the ocean.<ref name=pa20130930/>

SpaceX also ran a post-mission test on the [[second stage]].  While a number of the new capabilities were successfully tested on the September 29, 2013, CASSIOPE flight, there was an issue with the second stage restart test. The test to reignite the second stage [[Merlin (rocket engine family)#Merlin Vacuum .281D.29|Merlin 1D vacuum]] engine once the rocket had deployed its primary payload (CASSIOPE) and all of its nanosat secondary payloads was unsuccessful.<ref name=sn20130929>{{cite news |url=http://www.spacenews.com/article/launch-report/37450upgraded-falcon-9-rocket-successfully-debuts-from-vandenberg |archive-url=https://archive.today/20130930123920/http://www.spacenews.com/article/launch-report/37450upgraded-falcon-9-rocket-successfully-debuts-from-vandenberg |url-status=dead |archive-date=September 30, 2013 |title=Upgraded Falcon 9 Rocket Successfully Debuts from Vandenberg |work=Space News |first=Warren |last=Ferster |date=September 29, 2013 |access-date=September 30, 2013}}</ref>
The engine failed to restart while the second stage was coasting in low Earth orbit.