On flight day four, Dragon performed HA-3 and CE-3 thruster burns to bring it 2.5 km (1.6 mi) below the station once again.
NASA's Mission Control Houston team then gave SpaceX the go ahead to perform another set of burns that brought Dragon to within 1,400 m (4,600 ft) of the station.
Another decision was made at Mission Control Houston, and then Dragon moved to 250 m (820 ft) from the station.
At this point, the COTS 3 demonstration objectives began.
Dragon's DragonEye system demonstrated and confirmed that its position and velocity were accurate by comparing its LIDAR image to its thermal imagers.
A series of checkout maneuvers commenced.
The SpaceX flight control team in Hawthorne, California, commanded the spacecraft to approach the station from its hold position.
It moved from 250 to 220 m (820 to 720 ft) below the station.
The crew, using the command panel, then instructed Dragon to retreat, and the spacecraft moved back down to the hold point.
This test ensured that Dragon's range to the ISS was accurate, and that the flight control team saw the spacecraft's acceleration and braking perform as expected.
It was in a holding pattern at 250 m (820 ft), and once again the Dragon flight team commanded it to approach the station.
At the 220 m (720 ft) position, the crew commanded the vehicle to hold.

Another decision was made in Houston, and Dragon was permitted to enter the Keep-Out Sphere (KOS), a virtual area 200 m (660 ft) around the station intended to prevent collision with the orbiting complex.
Two additional and non-planned holds occurred: one at 150 m (490 ft) to further verify LIDAR; and finally one by SpaceX at 70 m (230 ft) to re-configure the LIDARs.
Stray reflections from the JAXA JEM module's External Facility (EF) caused interference with the LIDAR; SpaceX decided to narrow the LIDAR's field-of-view to eliminate the reflections.

Dragon proceeded to a position 30 m (98 ft) from the station and automatically came to a stop for a hold.
Another decision was made, and then Dragon proceeded to the capture point position at 9 m (30 ft).
A final decision was made, and the Mission Control Houston team notified the crew they were go to capture Dragon.
At that point, from the Cupola module, Expedition 31 crew member Don Pettit used the station's Mobile Servicing System (Canadarm2) to reach out and grapple the Dragon spacecraft at 13:56 UTC over Western Australia.
Upon capture, Pettit jokingly told ISS CAPCOM Megan McArthur, "Looks like we got us a Dragon by the tail.
We're thinking this sim went really well, we're ready to turn it around and do it for real."
Pettit, with the help of fellow crewmember André Kuipers, guided and then berthed Dragon to the Harmony module's Earth-facing Common Berthing Mechanism at 16:02 UTC.
On flight day four, Dragon performed HA-3 and CE-3 thruster burns to bring it 2.5 km (1.6 mi) below the station once again. NASA's Mission Control Houston team then gave SpaceX the go ahead to perform another set of burns that brought Dragon to within 1,400 m (4,600 ft) of the station. Another decision was made at Mission Control Houston, and then Dragon moved to 250 m (820 ft) from the station. At this point, the COTS 3 demonstration objectives began. Dragon's DragonEye system demonstrated and confirmed that its position and velocity were accurate by comparing its LIDAR image to its thermal imagers. A series of checkout maneuvers commenced. The SpaceX flight control team in Hawthorne, California, commanded the spacecraft to approach the station from its hold position. It moved from 250 to 220 m (820 to 720 ft) below the station. The crew, using the command panel, then instructed Dragon to retreat, and the spacecraft moved back down to the hold point. This test ensured that Dragon's range to the ISS was accurate, and that the flight control team saw the spacecraft's acceleration and braking perform as expected. It was in a holding pattern at 250 m (820 ft), and once again the Dragon flight team commanded it to approach the station. At the 220 m (720 ft) position, the crew commanded the vehicle to hold.
Another decision was made in Houston, and Dragon was permitted to enter the Keep-Out Sphere (KOS), a virtual area 200 m (660 ft) around the station intended to prevent collision with the orbiting complex. Two additional and non-planned holds occurred: one at 150 m (490 ft) to further verify LIDAR; and finally one by SpaceX at 70 m (230 ft) to re-configure the LIDARs. Stray reflections from the JAXA JEM module's External Facility (EF) caused interference with the LIDAR; SpaceX decided to narrow the LIDAR's field-of-view to eliminate the reflections.
Dragon proceeded to a position 30 m (98 ft) from the station and automatically came to a stop for a hold. Another decision was made, and then Dragon proceeded to the capture point position at 9 m (30 ft). A final decision was made, and the Mission Control Houston team notified the crew they were go to capture Dragon. At that point, from the Cupola module, Expedition 31 crew member Don Pettit used the station's Mobile Servicing System (Canadarm2) to reach out and grapple the Dragon spacecraft at 13:56 UTC over Western Australia. Upon capture, Pettit jokingly told ISS CAPCOM Megan McArthur, "Looks like we got us a Dragon by the tail. We're thinking this sim went really well, we're ready to turn it around and do it for real." Pettit, with the help of fellow crewmember André Kuipers, guided and then berthed Dragon to the Harmony module's Earth-facing Common Berthing Mechanism at 16:02 UTC.
SpaceX COTS Demo Flight 2