Dragon COTS 2,3 – Day 4


Joomla has the NASA / SpaceX Mission Briefing, which followed the Fly-Under on Flight Day 3.

Here are the slides and milestones for Flight Day 4 from the SpaceX Press Kit (pdf) for COTS 2,3.

Slide 2
Mission Profile for Dragon – Slide 2 – Flight Day 4 – Approach
Image Credit: SpaceX


  • Height adjust burn, Dragon begins burns that bring it within 2.5 km of station (GO/NO-GO)
  • Dragon again receives and sends information from/to the CUCU unit on station
  • Height adjust burn, brings Dragon 1.2 km from station (GO/NO-GO)
  • Height adjust burn, carries Dragon into the station’s approach ellipsoid (GO/NO-GO)

Slide 2
Mission Profile for Dragon – Slide 3 – Flight Day 4 – Capture
Image Credit: SpaceX

RBAR TO CAPTURE Day 4 (Slide 3)

  • Dragon LIDAR Demo, shows LIDAR is providing Dragon with necessary information for proximity operations
  • Dragon holds at 250 meters (GO/NO-GO) for Demo Maneuvers
  • Dragon begins R-Bar Demonstration (GO/NO-GO)
  • Dragon holds at 30 meters
  • Dragon holds at capture point, 10 meters below the station
  • Station’s robotic arm (SSRMS) captures Dragon (GO/NO-GO)
  • Dragon berths

NASA has announced that integrated operations will begin around 0700 UTC, after which the space station control team in Houston will have authority over the progress of the mission. This means that the initial approach procedure has a GO.

At 0615 UTC, the HA2 and CE2 burns have been completed and Dragon has arrived at the 2.5 kilometer level shown in Slide 2 above. Integrated Operations have begun.

At 0640, polling for the GO / NOGO decision on HA3 was completed, and a GO for HA3 was given. The commands have been sent to Dragon. HA3 is scheduled for 0705 UYC.

At 0705, HA3 has begun. And it is complete. At 0615 UTC, the HA2 and CE2 burns have been completed and Dragon has arrived at the 2.5 kilometer level shown in Slide 2 above. Integrated Operations have begun.

At 0640, polling for the GO / NOGO decision on HA3 was completed, and a GO for HA3 was given. The commands have been sent to Dragon. HA3 is scheduled for 0705 UYC.

At 0705, HA3 has begun. And it is complete.

At 0717 and 0734, a series of mid course corrections (MCC) are expected. This will bring Dragon to the 1.4 kilometer mark.

The HA4 (Approach Initiation) burn is scheduled for 0811 UTC, with MCC at 0828 and 0845. Arrival at the 250 meter mark is now expected at 0921 UTC, where Dragon will perform a series of Advance, Hold and Retreat maneuvers shown in slide 3. Capture is now schedule for 1159 UTC, a little earlier than anticipated yesterday.

U-Stream has Dragon in sight of the Space Station.

MC2 has been completed at 0739 UTC, and the CE3 burn will follow.

Dragon is now 10 kilometers behind and 1.4 kilometers below ISS.

Grappling and Berthing with the Canadarm will be controlled by Don Petitt, Andre Kuipers and Joe Acaba using the Robotic Work Station (RWS) aboard the ISS.

Crew Command Panel in the ISS Cupola
Image Credit: NASA TV

The CE3 burn began at 0749 UTC and is complete.

SpaceX controllers in Hawthorne are confirming that thermal imagers aboard Dragon are now picking up the ISS. Holly Ridings is polling her team at MCC-N in preparation for the HA4 burn. All stations are ready. The strobe light on Dragon has been turned on.

At 0812 UTC, the ISS is passing the east coast of the United States and heading into daylight. We should get some good views of Dragon.

The HA4 (AI) burn is now scheduled for five (5) minutes from now at 0820 UTC. And MCC confirms the burn has been completed.

Dragon Approaching from the 1.4 Kilometer Level (In Darkness)
Image Credit: NASA TV

An interview with astronaut Cady Coleman is coming up on NASA TV.

At 0844 UTC, Dragon has entered 1,000 kilometers.

At 315 Meters per SpaceX, closing at 0.24 meters/second.

At 0927, Dragon has closed to 275 meters.

At 0954, polling for demonstration maneuvers.

At 1008, Dragon is approaching 235 meters where the crew will issue a retreat command (second procedure in Slide 3 from left to right). Dragon will now retreat to 250 meters and hold.

1019 UTC, Dragon will resume the approach.

1020 UTC, Andre Kuipers has been told to issue a Hold command at 235 meters. This is the final maneuver on Slide 3 before continuing in toward capture.

At 1023, “Please send the Hold command now”. Andre has issued the Hold command. 237.4 meters and Holding.

Dragon Holding at 235 Meters from the ISS
Image Credit: NASA TV

In the darkness, you can see the strobe light and the thrusters firing (NASA TV).

Back in daylight at 1054 UTC, Dragon is holding at 236 meters while the data is being evaluated for a GO / NOGO decision on close approach. The LIDAR data is being cross checked against the thermal imaging data.

Mission Control has deemed the Hold and Retreat test to have been performed successfully.

At 1120 UTC Dragon is holding at 150 meters. This has been added by the crew. Don Petitt is asking about capture timing…thinks they may be grappling at night. Notes that all the SSRMS (Canadarm) lights are out. Ground has not determined a new capture time. Grappling will commence when Don says he has enough light.

At 1143 UTC, Dragon is continuing to 30 meters. This is expected to take about 30 minutes, which should put the Space Station in darkness (see here).

At 1200 UTC, Dragon is 100 meters from the space station. Both teams are monitoring the primary and secondary distances, which seem to be converging.

Coming up on sunset for ISS. Everyone is suggesting waiting for sunrise before capture. New capture time is 1310 UTC.

At 1200 UTC, Hawthorne has called a hold on the Dragon’s position 80 meters from ISS. The Hawthorne team is reconfiguring the LIDAR, swapping modes. Approach will resume. The SpaceX approach telecast will begin at 1245 UTC.

At 1220 UTC, Dragon is resuming the approach to 30 meters.

And now ground has called a retreat to 60 meters, and hold there. LIDAR data is the problem. Dragon holding at 72 meters.

Dragon and the ISS are about 20 minutes from sunrise. The hold is giving Hawthorne time to thoroughly test the LIDAR. SInce this is a test flight, they are testing. Gather as much data as you want and evaluate it. It will make future flights easier. And safer.

Sunrise at 1245 UTC. The problem seems to be reflections from the Japanese Experimental Module (JEM). The resolution appears to be to narrow the viewing angle of the LIDAR and avoid the stray reflections from JEM. Approach should resume in 5-10 minutes. Testing is good for new spacecraft.

At 1210, approach has resumed.

1213 and 30 meters and holding. It appears the LIDAR problem is resolved.

40 Meters
Dragon 40 Meters from the ISS
Image Credit: NASA TV

A key question now is whether there is enough time before sunset to move to 10 meters and perform the grapple. SpaceX and MCC-H (Houston) are polling for GO / NOGO decision on 10 meters. Hawthorne is GO. Still polling MCC-H. And the ISS crew is configuring the external cameras for capture.

At 1330, Dragon is moving to ten meters, about 20 minutes, for grapple. Approaching sunset and TDRS LOS in a little less than eight minutes.

1344 UTC and 15 meters. The strobe has been turned off.

11 Meters and one final poll to approve the grapple maneuver. And the answer is GO!

Capture Confirmed!!

2 thoughts on “Dragon COTS 2,3 – Day 4

  1. Pingback: May 2012 « NSS Phoenix Space News

  2. Pingback: Dragon COTS 2,3 – Day 5 – Hatch Opening « The National Space Society of Phoenix

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