SpaceX\u2019s Dragon is now through the opening stages of being berthed on the International Space Station (ISS), after the spacecraft was captured by the Space Station Remote Manipulator System (SSRMS) on Friday. The effort to fully install Dragon to the ISS will continue throughout the day, although the major elements of the historic milestone have now been completed.<\/p>\n
Dragon\u2019s Big Day:<\/p>\n
The first private spacecraft to visit the ISS had already completed the the C2 objectives of the combined C2\/C3 mission by early Friday, already a great achievement for what is only Dragon\u2019s second journey into space.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z320.jpg\" "\\"Z3\\"")
The big test for the C2 portion of the test flight involved a fly under of the ISS to test a number of critical systems that are required for the berthing attempt, as Dragon completed a lap around the Station on what has been described as a racetrack. (Over 300mb of Dragon flyunder Hi Res Images \u2013 the entire image dump from the ISS \u2013 available in L2 \u2013 LINK)<\/p>\n
Coming out of far field phasing, Dragon fly just over 10km under the ISS, a distance that allowed for a test of the UHF communication system between the orbital outpost and the commercial spacecraft via the Commercial Orbital Transportation Services (COTS) Ultra High Frequency (UHF) Communication Unit (CUCU).<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z661.jpg\" "\\"Z66\\"")
The test \u2013 also including checkouts of the Light Detection And Ranging (LIDAR) hardware and GPS \u2013 was a success, marked by the ISS crew managing to command a strobe light on the Dragon, showing they had the ability to communicate with the spacecraft.<\/p>\n
\u201cSpaceX and ISS Communication check \u2013 COTS UHF Communications Unit (CUCU) bidirectional communication was established successfully at ~ 10.4 km range during SpaceX Dragon Fly Under demo was successful. The Crew performed Strobe light ON command via Crew Command Panel (CCP),\u201d noted Status Update information via L2 \u2013 (LINK).<\/p>\n
\u201cCrew used Laser Instrument Distance and Range (LIDAR) to determine the Dragon range (2780 meters) once Dragon crossed the R-Bar. Crew powered off the Dragon Strobe light via CCP at the end of Fly By demo. Dragon navigational system also functioned successfully.\u201d<\/p>\n
The ISS\u2019 Space Integrated GPS\/Inertial Navigation Unit (SIGI), one of two GPS units required for Dragon\u2019s Relative GPS (RGPS) navigation, also worked without issue, following some late evaluations ahead of the mission to ensure the availability after requirements to Removed & Replace (R&R) one of the units after data showed the old unit was in a degraded state.<\/p>\n
\u201cThe ISS Space Integrated Global Positioning System\/ Inertial Navigation System (SIGI)s were configured for 12-channel mode during the SpaceX Dragon Fly Under Demo,\u201d added the notes. \u201cThe SIGIs regularly tracked 8 or 9 satellites between ISS and Dragon. Both ISS SIGIs are back in 6-channel mode and outputting attitude updates.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z731.jpg\" "\\"Z73\\"")
A minor issue relating to the berthing attempt was observed on Thursday, as ISS crewmember Don Petitt called down to note one of the Robotic Work Station (RWS) monitors in the Cupola was failing to display information.<\/p>\n
Options existed to move to the Lab\u2019s RWS for the berthing attempt, or replace one of the lab monitors in the Cupola. However, the monitor was fixed via troubleshooting.<\/p>\n
\u201cCupola Robotic Work Station (RWS) Monitor 1 Failure: After ground powered-up the Cupola RWS, crew entered the Cupola and found Monitor 1 to have no video or data, just some horizontal red and white lines near the middle of the screen indicating a sync problem. The crew cycled power via UOP1 in the Cupola and the monitor was recovered,\u201d added the Status update.<\/p>\n
\u201cAll 3 Cupola monitors have been confirmed functional, and are expected to remain powered through SpX-D capture and berthing. Initial indications are that this is a video sync initialization issue that could only occur at powerup (i.e., should not occur once a monitor is powered and receiving a good sync signal), so no issues are expected for capture or berthing.\u201d<\/p>\n
Click here for other Dragon News Articles: http:\/\/www.nasaspaceflight.com\/tag\/dragon\/<\/p>\n
The Node 2 Nadir (N2N) Common Berthing Mechanism (CBM) Loss of Communication (LOC) Anomaly was also discussed. However, this was also recovered, deemed to be in an acceptable condition, resulting in the ISS being \u201cready to support SpaceX berthing\u201d.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z11122.jpg\" "\\"Z1112\\"")
For the next big milestone, berthing, Dragon was put through a series finite manuevers, mainly to ensure the safety of the orbital outpost \u2013 and its crew \u2013 as the vehicle enters the safety zone surrounding the Station.<\/p>\n
First up for Dragon was a repeat of the first part of Flight Day 3\u2019s racetrack profile, as the spacecraft once again catches up to the Station via the Hight Adjustment (HA) and Co-Elliptical (CE) burn, bringing Dragon 2.5 km below ISS. A Go\/No-Go was then performed for the HA3\/CE2 burn pair bringing Dragon to 1.2 km below ISS.<\/p>\n
The HA3\/CE3 burn pair, using RGPS and configured with the ISS\u2019 own GPS system, were then conducted, followed by the HA4 (Ai) burn, taking Dragon inside the corridor where the crew begins to monitor the spacecraft\u2019s approach. With \u201cTally-Ho\u201d on the Dragon for the second time in this mission \u2013 this time with its strobe light clearly visible \u2013 the spacecraft then into the business end of it\u2019s rendezvous operations.<\/p>\n
This resulted in Dragon arriving \u2013 and holding at \u2013 250 meters from the Station, where checks of Dragon\u2019s LIDAR system were conducted, a key element of hardware that has a heritage of testing via the Space Shuttle Discovery during her STS-133 mission. A retreat was called to test the abort capability, prior to moving forward again to a 235m hold point.<\/p>\n
With hold and retreat demos being conducted, yet more Go\/No Go polling were conducted by controllers at the Johnson Space Center (JSC) Flight Control Room (FCR) and at SpaceX\u2019s Mission Control in California.<\/p>\n
Dragon was then commanded to 200 meters from Station, to allow for better data from the Thermal Imagers on the spacecraft. This was followed by another additional hold point of 150 meters, inside the \u201ckeep out sphere\u201d.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z4711.jpg\" "\\"Z471\\"")
Next, Dragon was given a \u201cGo\u201d to approach to 30 meters distance from the Station where it will automatically hold. Controllers noted that the Thermal Imagers will continue to be evaluated during the approach. However, another hold was called \u2013 this time by SpaceX \u2013 in order to reconfigure the LIDAR system to a different mode.<\/p>\n
A retreat to 70 meters was then called by SpaceX, who are continuing to take a \u201cclose look\u201d at the LIDAR data.<\/p>\n
The problem was deemed to be via \u201cstray reflections\u201d from the JAXA JEM module\u2019s External Platform (EP) impacting on the LIDAR. The teams decided to narrow the view range of the LIDAR to remove the reflections from the field of view.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z417.jpg\" "\\"Z4\\"")
This allowed for a \u201cGo\u201d is given to make the full trip to 30 meters from Station, ahead of Dragon entering the critical phase of approaching the ISS, proceeding from 30m to the Capture Point at 10 meters out, where Dragon automatically held. The ISS\u2019 robotic assets \u2013 already translated to the pre-capture position \u2013 were then prepared to move towards the Dragon from the Cupola RWS.<\/p>\n
This came after the final Go\/No Go poll was performed for Capture, as the crew is informed of the postive decision from the ground.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z67.jpg\" "\\"Z6\\"")
Upon receiving the \u201cGo for Capture\u201d call from Houston, the ISS crew armed the SSRMS capture command and begin tracking the vehicle through the camera on the Latching End Effector (LEE) of the SSRMS, noted an overview presentation (L2 \u2013 Link).<\/p>\n
With the ISS\u2019 thrusters inhibited and Dragon confirmed to be in free drift, the arm\u2019s LEE will be maneuvered over the Grapple Fixture (GF) pin on Dragon to trigger the capture sequence ahead of pre-berthing maneuvers.<\/p>\n
With the addition of several holds into the timeline, capture was confirmed later than expected, at 13:56 GMT.<\/p>\n
The Dragon, now secured by the SSRMS, was carefully translated to the pre-install set-up position, 3.5 meters away from the Station\u2019s module, allowing the crew to take camcorder footage of the vehicle through the Node 2 windows. This footage will then be downlinked to the ground for engineers to evaluate the condition of the Dragon spacecraft.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z76.jpg\" "\\"Z7\\"")
The SSRMS was then maneuvered Dragon to the second pre-install position, at a distance of 1.5 meters out. Desats were inhibited prior to the maneuver of the Dragon into Common Berthing Module (CBM) interface to begin the securing of the spacecraft to the ISS.<\/p>\n
A \u201cGo\u201d at this point was marked by all four Ready To Latch (RTL) indicators providing confirmation on the RWS panel.<\/p>\n
As has been seen with other arrivals \u2013 and indeed new additions to the Station itself \u2013 Dragon was then put through first stage capture tasks, allowing the SSRMS to go limp, ahead of second stage capture, officially marking Dragon\u2019s berthing with the ISS at 11:02 Central Time.<\/p>\n
With the SSRMS now keeping hold of Dragon through most of the mission \u2013 per NASA\u2019s coverage \u201cas a precaution\u201d \u2013 there remains one major robotic operation to come ahead of unberthing.<\/p>\n
This will begin on Sunday, when the SSRMS is set to pick up the Special Purpose Dexterous Manipulator (SPDM) \u2013 otherwise known as Dextre \u2013 allowing it to greet the new member of the ISS resupply family.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/05\/Z562.jpg\" "\\"Z56\\"")
The plan involving Dextre is related to performing a survey of the Dragon trunk using SPDM at the end of the SSRMS, after the big arm retrieves its Canadian cousin from the Mobile Base System at Work Station 5 (WS5).<\/p>\n
Dragon\u2019s trunk \u2013 per the plan \u2013 is to be surveyed using Dextre\u2019s own LEE and Camera Light Pan Tilt Assembly (CLPAs), under the control of MCC-Houston. This task is to allow for teams on the ground to assess viewing and lighting conditions to aid in operations planning for future trunk cargo extraction\/insertion operations that will play a resupply role during future missions.<\/p>\n
Once the survey has been completed, per the plan, the SSRMS will return Dextre to the MBS, which will then carry the robot back to Work Station 2 (WS2).<\/p>\n
According to NASA PAO in response to NASASpaceflight.com, this robotic operation will begin at 4pm Central time, under the control of ground teams.<\/p>\n
Meanwhile, the Dragon has successfully been ingressed early on Saturday, following leak checks and hatch opening. This marks the official start of cargo operations, removing Dragon\u2019s manifested items and preparing to load Dragon up with a quality of downmass to return to Earth.<\/p>\n
This article will be updated throughout the major events.<\/p>\n
(Images: NASA, CSA, SpaceX and via L2\u2019s SpaceX Dragon C2+ Mission Special Section \u2013 Containing presentations, videos, images, interactive high level updates and more, with additional images via NASA, SpaceX). <\/p>\n
(Click here: http:\/\/www.nasaspaceflight.com\/l2\/ \u2013 to view how you can support NSF and access the best space flight content on the entire internet).<\/p>\n","protected":false},"excerpt":{"rendered":"
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