CRS-10 Dragon aborts rendezvous and berthing with Station
After lifting off from historic LC-39A at the Kennedy Space Center, FL, on Sunday morning, SpaceX’s Dragon capsule for the SpX-10/CRS-10 mission aborted an approach to the International Space Station during rendezvous and berthing operations. The mission – which is delivering thousands of pounds of supplies, hardware, food, and experiments to the ISS – will make a second attempt on Thursday.
Cruising to orbit on her Falcon 9 first and second stages, the SpX-10 Dragon spacecraft had slipped into her preliminary orbit without issue.
Meanwhile, the Falcon 9 first stage successfully flew itself back to the Cape Canaveral Air Force Station’s Landing Zone 1 (LZ-1) for the third landing of a SpaceX rocket on land.
In the immediate hours after liftoff, teams performed a quick assessment of Launch Complex 39A, starting the process of documentation of all elements of the pad damaged during Sunday’s launch.
Damage to the launch pad is always expected following the liftoff of a rocket generating over a million pounds of thrust.
However, the Falcon 9’s ~1.71 million pounds of thrust is relatively nothing compared to the ~7 million pounds of thrust LC-39A endured during its days with the Space Shuttle program, and SpaceX officials in the post-launch news conference were confident that only cosmetic damage would be present at LC-39A.
Accordingly, the quick look condition of the pad on Sunday afternoon noted that the launch complex appeared to be in excellent condition.
With the U.S. federal holiday on Monday, teams began a more thorough and extensive inspection on Tuesday of the launch pad’s systems and support services – an inspection that will reveal just how much work and time it will take to refurbish the historic pad ahead of the currently planned – albeit unlikely – for the 28 February launch of the Echostar XXIII mission.
Rendezvous and berthing:
Following orbit insertion, Dragon performed a series of trajectory adjustment burns over the capsule’s three-day chase with the orbital outpost to properly align itself 6 km from the Station on Wednesday morning for final approach operations.
Following approval from NASA, SpaceX controllers commanded Dragon to begin its final approach sequence with the HA4 Approach Initiation burn at 03:16:00 EST – at which time the ISS crew began actively monitoring the spacecraft.
Notably, this was deemed to have occurred 15 minutes ahead of schedule.
This was a potential sign of a problem, as Dragon then opted to abort her approach as a “bad value” in an ISS State Vector and a relative GPS error was noted by her flight computer.
The ability for Dragon to maintain proper alignment with the ISS is provided by the Relative Navigation System – which was developed by SpaceX and debuted on CRS-3 on 20 April 2014.
The spacecraft was 1.2 km from the Station when the abort was called.
Dragon’s abort corridor will see her move into a racetrack around the Station, allowing for a second attempt to take place in 24 hours.
This will begin with the HA4 series of maneuvers started with the 7-second HA4 burn that changes Dragon’s relative velocity to the ISS by 0.3 m/s.
This will be followed by the HA4-MC1 and the HA4-MC2 burns designed to keep Dragon properly aligned with her targeted 350 m hold point.
Once Dragon arrives at the 350 m hold point she will fire her thrusters to hold relative position with the Station – at which time controllers at SpaceX’s Mission Control Center (MCC-X) in Hawthorne, CA, will command Dragon to perform a 180 degree Yaw maneuver to place the craft into the proper orientation for grapple at the end of the approach sequence.
After the yaw maneuver, MCC-X and MCC Houston (MCC-H) controllers will confirm the health of Dragon’s systems, after which the spacecraft will depart the 350 m hold point.
The next hold point for Dragon is at 250 m below the ISS, where controllers will once again confirm the health of Dragon’s systems as well as the craft’s orientation before giving a “go” to press ahead toward capture.
To date, Dragon has never misbehaved on approach to ISS.
For the rendezvous, once a “go” to proceed is given, Dragon will leave the 250 m hold point and 33 minutes later arrive at the 30 m hold point.
Once here, teams will perform final assessments of Dragon’s readiness to close to the capture point 10 m below the ISS.
Under the ideal plan, Dragon will depart the 30 m hold point and arrive at the 10 m Capture Point (CP).
Once Dragon arrives at the CP, ISS Commander Shame Kimbrough and Flight Engineer Thomas Pesquet – working in the Robotic Work Station in the Cupola lab – will extend the Space Station Remote Manipulator System (SSRMS) arm toward Dragon’s grapple fixture.
At this point, Kimbrough and Pesquet will “inhibit” the Station’s thrusters and Dragon will be commanded to “free drift” mode.
Kimbrough and Pesquet will then move the SSRMS over the Dragon’s grapple fixture pin and trigger the capture sequence.
Assuming a nominal, prime timeline, capture is expected at 06:00EST (11:00 UTC).
The backup capture window, should something preclude capture in the prime window, opens at 07:03:22 EST and closes at 08:20:08 EST.
After capture, a series of initial post-grapple checkouts will occur before Kimbrough and Pesquet carefully translates Dragon to its pre-install position 3.5 m away from Node-2 Harmony’s nadir port.
Once at the pre-install position, Station crewmembers will take camcorder and photographic footage of Dragon for post-launch and rendezvous engineering evaluation.
Kimbrough and Pesquet will then move Dragon to 1.5 m from Node-2, at which point the ISS crew will wait for the final “go for berthing” call to move Dragon the rest of the way into the Common Berthing Module interface to begin securing the spacecraft to the Station.
Under the current plan, the CRS-10 Dragon will remain berthed to the ISS until late March, at which point it will reenter Earth’s atmosphere and splashdown for recovery in the Pacific Ocean.
SpaceX waves off space station cargo delivery for a day
SpaceX’s Dragon supply ship, loaded with nearly 5,500 pounds of cargo and experiments, aborted an approach to the International Space Station on Wednesday after encountering a problem in its GPS navigation system.
The gumdrop-shaped, solar-powered spacecraft was about 1,200 feet, or 365 meters, from the space station when it automatically bailed out of the rendezvous, escaping the immediate vicinity of the research outpost as its safety system intended and setting up for another approach as soon as Thursday.
NASA said SpaceX’s mission director at the Dragon control center in Hawthorne, California, reported the aborted rendezvous at 3:25 a.m. EST (0825 GMT) when the spacecraft ran into trouble processing GPS navigation data.
“The SpaceX engineers are tracing this issue to an incorrect value that was detected in the spacecraft’s Relative Global Positioning System hardware, which basically tells Dragon’s computers, for its burn plan, where it is in the sky relative to the International Space Station,” said Rob Navias, a NASA spokesperson providing commentary on NASA TV.
“Dragon itself is in excellent shape,” Navias added. “Its Global Positioning System hardware is also in excellent shape.”
The Dragon spacecraft’s navigation system works by comparing position data derived from the GPS satellites to determine the range, direction and closing rate between the visiting supply ship and the space station.
Once the cargo craft gets closer to the complex, the navigation system switches to inputs from a pulsed laser ranging instrument and a thermal camera to determine how far Dragon is from the space station.
The rendezvous is fully automated, with the exception of some manual abort, retreat and hold commands.
“SpaceX mission officials are fully confident that that issue can be mitigated, and that the spacecraft can be protected from an incorrect value during the re-rendezvous attempt on Thursday morning,” Navias said. “That will allow Dragon to safely approach the station for a grapple and a berthing to the Earth-facing port on the Harmony module.”
Wednesday’s abort was the first such wave-off by a SpaceX supply ship in 10 cargo deliveries since 2012. NASA’s other cargo transportation provider, Orbital ATK, had to upload a software patch to one of its Cygnus logistics freighters on a flight in 2013 to correct a GPS error, delaying its arrival at the space station by a week.
NASA said the Dragon spacecraft went into a so-called “race track” course in front, above, and then behind the space station to set up for another rendezvous attempt Thursday, part of a predetermined trajectory to be used in case a problem prevents an on-time arrival.
“At no time was the station or the crew in any danger,” Navias said. “Dragon did exactly what it was supposed to do and broke out of its approach.”
Astronaut Mike Hopkins in space station mission control in Houston passed the news on to space station flight engineer Thomas Pesquet, who was preparing to capture the Dragon spacecraft with the lab’s robotic arm.
“I just want let you know that Dragon is on a 24-hour safe trajectory,” Hopkins said. “We had an RGPS filter unconverged, and we’re currently in the works for planning a re-attempt for tomorrow.”
“OK, I copy, thanks for the explanation, and I look forward to welcoming Dragon on-board tomorrow then,” Pesquet replied.
Shortly after 4:30 a.m. EST (0930 GMT), Hopkins radioed space station commander Shane Kimbrough that mission control aims to try for another rendezvous Thursday. If the rendezvous goes ahead, the Dragon cargo craft should be grappled by the station’s robotic arm around 6 a.m. EST (1100 GMT).
“Dragon has plenty of propellant,” Navias said. “Its other systems are in excellent shape, and all of the science on-board the Dragon can withstand a 24-hour re-rendezvous.”
The Dragon spacecraft would approach the space station from below, pausing at several hold points before reaching a “capture box” around 30 feet, or 10 meters, from the outpost.
Pesquet will maneuver the robotic arm to snare the free-floating spaceship, and then ground controllers will take command of the arm to berth Dragon to the station’s Harmony module for unpacking.
The astronauts will unload scientific gear, food and other items stowed inside Dragon’s pressurized compartment, and the station’s robotics systems will pull two experiment packages out of the spaceship’s external payload bay for mounting outside the research complex.
One of the external experiments developed by NASA will monitor changes in Earth’s ozone layer, and the other payload hosts more than a dozen NASA and U.S. military investigations, including a lightning imager and a testbed to gather data for future satellite servicing missions.
Wednesday’s Dragon rendezvous wave-off came a few hours after a Russian Progress refueling and resupply freighter launched from the Baikonur Cosmodrome in Kazakhstan.
The Progress MS-05 spacecraft is on track to dock with the space station’s Pirs module at 3:34 a.m. EST (0834 GMT) Friday, less than 24 hours after Dragon’s new arrival time.
The SpaceX Dragon was pictured from a video camera as it approached the space station Wednesday morning.
NASA and SpaceX flight controllers in Houston and Hawthorne, California are reworking plans for the arrival Thursday of the SpaceX Dragon cargo craft after its rendezvous to the International Space Station was aborted early Wednesday morning. The Dragon’s computers received an incorrect navigational update, triggering an automatic wave off.
Dragon was sent on a “racetrack” trajectory in front of, above and behind the station for a second rendezvous attempt Thursday. Dragon is in excellent shape and neither the crew nor the station were in any danger. NASA TV will cover its second rendezvous attempt Thursday beginning at 4 a.m. EST.
Expedition 50 commander Shane Kimbrough and Thomas Pesquet will be back in the cupola Thursday waiting to capture Dragon at around 6 a.m. Flight Engineer Peggy Whitson will be assisting the duo monitoring Dragon’s arrival and its systems.
A few hours before Dragon aborted its rendezvous, Russia launched its Progress 66 (66P) resupply ship from Kazakhstan on a two-day trip to the station’s Pirs docking compartment. The 66P is carrying nearly three tons of food, fuel and supplies to the six-member Expedition 50 crew. It will arrive Friday for an automated docking at 3:34 a.m. and stay at the station until June. NASA TV will also cover its arrival starting at 2:45 a.m.
The SpaceX Dragon is pictured in the grips of the Canadarm2 shortly after its capture by astronauts Shane Kimbrough and Thomas Pesquet. Credit: NASA TV
While the International Space Station was traveling about 250 statute miles over the west coast of Australia, Expedition 50 Commander Shane Kimbrough of NASA and Flight Engineer Thomas Pesquet of ESA (European Space Agency) captured Dragon a few minutes ahead of schedule at 5:44 a.m. EST.