Less than three days since it launched its mighty Antares booster from Pad 0A at the Mid-Atlantic Regional Spaceport (MARS) on Wallops Island, Va., Orbital Sciences Corp. has triumphantly brought its second “dedicated” Cygnus cargo ship—and its third overall, counting last September’s ORB-D “Demonstration” mission—to a smooth berthing at the International Space Station (ISS). Flying 260 miles (420 km) above northern Libya, Cygnus was grappled by the station’s 57.7-foot-long (17.6-meter) Canadarm2 robotic arm at 6:36 a.m. EDT Wednesday, 16 July. Fittingly for a spacecraft whose name is the Latin for “swan,” today’s capture was led by Expedition 40 Commander Steve Swanson. A little more than two hours later, at 8:53 a.m., the cargo craft was firmly berthed at the “nadir” (or Earth-facing) port of the Harmony node, preparatory to hatch opening and crew ingress. Click here to see AmericaSpace’s stunning imagery of the ORB-2 launch.
In anticipation of today’s capture and berthing, Swanson and his U.S. Orbital Segment (USOS) crewmates, Alexander Gerst of Germany and Reid Wiseman of NASA, spent part of Tuesday performing a routine practice session with the robotic assets they would use, including the Robotics Onboard Trainer (ROBoT). They also studied plans for pressurizing the vestibule of Harmony’s nadir Common Berthing Mechanism (CBM), which would be done just prior to opening the hatch into Cygnus. Gerst—whose national football team triumphantly won the World Cup on Sunday, in a match closely watched by the Expedition 40 crew, via laptop—set up a small television camera and routed power and data cables from Japan’s Kibo laboratory into the station’s multi-windowed cupola. These cables were destined to support the Hardware Control Panel (HCP), used to communicate with Cygnus during rendezvous. Early Wednesday, the trio assembled inside the cupola, with Swanson and Gerst leading the operation and Wiseman co-ordinating their activities.
Just after 5 a.m. EDT, Wiseman tweeted a photograph and proudly proclaimed: “First tiny glimpse of @OrbitalSciences #Cygnus #Orb2 – lower right over the ocean.” In the image, the cargo craft’s brilliantly lit solar arrays could just barely be seen against a cobalt blue backdrop of Earth’s oceans. Minor technical issues with NASA TV coverage notwithstanding, the rendezvous ran according to schedule, and at 5:30 a.m.—about 67 minutes ahead of the planned capture time—NASA tweeted that Cygnus was at a distance of 3,300 feet (1,000 meters) from the ISS. Shortly thereafter, when NASA TV coverage came online, commentator Rob Navias reported that the cargo craft had closed the distance to 820 feet (250 meters). At this stage, it held position, preparatory to permission being granted by Mission Control in Houston, Texas, and Orbital Sciences’ Cygnus Flight Control Room in Dulles, Va., to proceed within the so-called “Keep Out Sphere” (KOS). This virtual exclusion zone extends 660 feet (200 meters) around the ISS to prevent the risk of a collision.
All rendezvous and phasing maneuvers executed by Cygnus over the last three days have gone extremely smoothly, Navias told his audience, adding that they were all “precise and on-time.” With NASA Flight Director Emily Nelson overseeing today’s rendezvous and berthing operation, Capcom Catherine “Cady” Coleman informed Swanson at 5:45 a.m. that Cygnus had been given a “Go” to proceed inside the KOS. Despite her heavy workload, Coleman found time to retweet Wiseman’s earlier photograph, with the note: “It’s like being on-board!” Both Coleman and her fellow Capcom, veteran astronaut Doug Wheelock, are former ISS long-duration residents, having flown to the station in 2010-2011. Later, Wheelock tweeted his own view, showing a pair of “Cyggi” toy swans—clad in appropriate Orbital Sciences attire—atop his own console.
By 6:00 a.m., Orbital tweeted that Cygnus was at a distance of about 330 feet (100 meters) and closing, with the spacecraft’s strobe lights clearly visible. Also visible, far “below,” as the ISS passed over Baja California, were lightning flashes. A few minutes later, advancing smoothly, Cygnus reached its final “hold point” at 98 feet (30 meters) at 6:10 a.m. Hitting orbital sunrise at about the same time, Cady Coleman radioed Swanson with the tongue-in-cheek quip, “It wasn’t us who turned on the lights!”
Following a poll of all flight controllers, a “Go” was issued at 6:18 a.m. to depart its final hold point and close to 30 feet (10 meters), which would place it within range of Canadarm2. At this stage, Wiseman and cosmonaut Aleksandr Skvortsov—one of three Russian members of the Expedition 40 crew—joined Swanson and Gerst inside the cupola to begin taking photographs. “Scintillating” images of the incoming Cygnus were also acquired by the High-Definition Earth Viewing (HDEV) camera on the exterior of Europe’s Columbus laboratory. This system of high-definition cameras and live Internet video streaming equipment was delivered to the ISS aboard SpaceX’s most recent Dragon mission (SpX-3) in April. By 6:27 a.m., moving at just 0.6 feet (0.2 meters) per second, Cygnus had reached the 30 feet (10 meters) capture point.
Four minutes later, at 6:31 a.m., Coleman gave them a formal “Go for Capture.”
“Station copies all,” replied Gerst. “We’re Go for Capture.”
At this stage, the ISS was placed into “free drift,” with all thrusters disabled to ensure that no disturbances were imparted between the two vehicles, as Swanson and Gerst inched Canadarm2’s Latching End Effector (LEE) closer to the grapple pin on Cygnus. At 6:36 a.m., a few minutes ahead of schedule, Swanson executed a perfect grapple of Cygnus, which has been named—in Orbital Sciences tradition—in honor of a deceased astronaut; in this case, five-time shuttle flier and former Orbital engineer Janice Voss, who died of cancer two years ago. At the time of capture, Cygnus was flying high above northern Libya. “The Swan arrives at its #ISS nest,” tweeted Orbital in the minutes after capture. Counting the ORB-1 mission in January 2014 and the ORB-D (“Demonstration”) mission last year, today’s capture marked the third occasion on which a Cygnus has come knocking at the door of the ISS.
“Houston, Station on 2, we now have a seventh crew member,” radioed Swanson. “Janice’s legacy continues. Welcome aboard the ISS, Janice.” Touchingly, Cady Coleman responded with her own words of tribute, describing Voss as “a friend, a colleague and a crewmate” who achieved an enormous amount in the interests of exploration. Perhaps offering a nod toward Capcom Charlie Duke’s words to Apollo 11 astronauts Neil Armstrong and Buzz Aldrin—who launched toward the Moon, 45 years ago today—Coleman told the Expedition 40 crew that she and her colleagues in Mission Control “were breathing again.”
Interestingly, in early 1997, Coleman trained for a few weeks as a backup crew member on STS-83, when fellow astronaut Don Thomas suffered a broken ankle. Janice Voss served as the payload commander for that flight. Orbital also paid its own tribute “to salute our friend and colleague,” since Voss had worked for the company between 1987 and 1990, providing mission integration and flight operations support for the Transfer Orbit Stage (TOS) booster, before she became an astronaut. The TOS was used in the 1990s to launch the Advanced Communications Technology Satellite (ACTS) on shuttle mission STS-51, as well as NASA’s ill-fated Mars Observer.
Immediately after capturing Cygnus, the Expedition 40 crew took a break, as NASA’s Melanie Miller—the robotics officer in Mission Control—remotely commanded Canadarm2 to maneuver the cargo craft into an “Installation Position” to permit its Passive CBM to align with the Active CBM on Harmony’s nadir port. “Mission Control Houston is remotely guiding #Cygnus to Node-2 [Harmony] using the #Canadarm2,” Wiseman tweeted at 7:50 a.m. During this procedure, Miller had carefully positioned Cygnus at the Ready to Latch (RTL) point at 8:42 a.m., after which Wiseman took over the final phases of the berthing issuing commands through a laptop. The two-part berthing process saw hooks from Harmony’s Active CBM extend and grab Cygnus to pull their respective berthing mechanisms into contact at 8:51 a.m., after which a series of 16 bolts were driven to rigidize the two spacecraft. “Hard mate” between Cygnus and the ISS was achieved at 8:53 a.m., as they orbited high above the east coast of Australia. The robotics officer in Mission Control then ungrappled Canadarm2 and placed the arm into a “parked” position.
Although crew ingress into Cygnus was originally scheduled for 6:00 a.m. EDT Thursday, it was stressed by Rob Navias that past precedent has shown that astronauts typically work ahead of the timeline and will undoubtedly be eager to open the hatch into the newly-arrived cargo craft at the earliest opportunity. With this in mind, Navias pointed out that ingress might be attempted as early as Wednesday afternoon, after the completion of pressure and leak checks.
The ORB-2 Cygnus mission is scheduled to remain berthed at the ISS until 15 August. Excluding ORB-D, which was conducted under the language of the earlier Commercial Orbital Transportation Services (COTS) contract, ORB-2 is the second of eight contracted flights, under a $1.9 billion Commercial Resupply Services (CRS) contract, signed between NASA and Orbital Sciences in December 2008. With at least one further Cygnus flight planned in 2014, and as many as three next year, all missions under Orbital’s CRS contract are expected to be complete by 2016, delivering a total of 44,000 pounds (20,000 kg) of critical equipment and crew supplies to the ISS.
Aboard ORB-2 is 3,293 pounds (1,493 kg) of cargo, including crew “care packages” from their families and friends, and foodstuffs. Additionally, vehicle hardware, medical supplies, equipment for the Environmental Control and Life Support System (ECLSS), EVA tools, and parts for the space station’s electrical system. Scientific experiments aboard Cygnus include no less than 28 small CubeSats, known as “Flock 1b,” which will be deployed from the airlock of Japan’s Kibo laboratory and will form part of a wider “Dove” constellation of small satellites to gather expansive imagery of Earth “to help identify and track natural disasters and responses to them” and “to improve environmental and agricultural monitoring and management.” Also aboard is TechEdSat-4, which will be deployed via Kibo’s Small Satellite Orbital Deployer, and seeks to develop a tension-based drag device, known as the “Exo-Brake,” whilst the National Center for Earth and Space Science “Charlie Brown” experiment—conducted in association with the Student Spaceflight Experiment Program (SSEP)—includes 15 investigations into food growth and consumption, the effects of microgravity upon the oxidation process, and the production of penicillin in the microgravity environment of low-Earth orbit.
Present plans call for the ORB-2 Cygnus to be robotically detached from the ISS on 15 August. It will then “be guided to a safe distance away from the orbiting laboratory.” However, according to NASA’s ORB-2 press kit, unlike its ORB-D and ORB-1 predecessors, it will not be immediately plunged to a destructive re-entry in the upper atmosphere. “The Cygnus spacecraft will fly an additional 15 days after departure to conduct spacecraft engineering tests to support future mission objectives,” it was explained. “At the end of that free-flight period, Cygnus will perform a series of engine burns, so that it will re-enter Earth’s atmosphere for a destructive re-entry over the South Pacific Ocean.” The spacecraft will take with it about 2,967 pounds (1,346 kg) of unneeded gear for disposal.