This evening, while Orbital Sciences Corp. and NASA celebrate a successful Antares Orb-2 launch, SpaceX is preparing for their own launch from Cape Canaveral, Fla., tomorrow morning, one which is expected to deliver the first six of 17 next-generation telecommunications satellites to orbit for customer ORBCOMM.
Launch of the mission, designated OG2 Mission 1, has been delayed numerous times, for various reasons, since last May. A considerable helium leak occurred during fueling of the Falcon-9 v1.1 rocket’s first stage May 8 while preparing for a customary static test fire prior to a launch attempt. Repairs required the rocket be rotated back horizontal and rolled back into the integration facility at Space Launch Complex-40. Hardware from the first stage was removed and returned to SpaceX headquarters in Hawthorne, Calif., for inspections and verifications to ensure that the problem did not represent a systemic failure and a threat to future missions.
A new launch date of June 11 was then selected to give teams at the Cape additional time to carry out the lengthy process of re-encapsulating the OG-2 satellites back into their adaptor for launch, but when a minor issue was encountered with one of the six satellites during those operations the launch date slipped further to June 20 to allow workers to perform precautionary steps to ensure there were no operational concerns with the satellite.
Then came June 20, launch day, and then came another technical issue, this time when the launch team identified an apparent “pressure decrease” in the second stage of the Falcon-9 rocket during final countdown operations.
A second launch attempt was made the next day, but stormy summertime Florida weather forced SpaceX to stand down yet again. Adding insult to injury, the company failed to provide a live streaming webcast of the countdown, which put the spotlight on the company for the wrong reasons as many in the public and media made it loud and clear across social media their disgust with the company’s decision to not provide coverage at all.
The third time was not the charm for SpaceX either, as a third launch attempt was called off during the countdown June 22 when standard pre-flight checks identified a problem with a thrust vector control actuator on the rocket’s first stage.
All the while the U.S. Air Force Eastern Range, responsible for providing Range safety and support for all launches off the Cape, was waiting to begin a two-week shutdown for scheduled maintenance. With three scrubs, two for technical issues, SpaceX decided to stand down so the Range could work, and later negotiated the next launch attempt with the Eastern Range for Monday, July 14.
When they do eventually make it into space, the six OG-2 satellites will enter a circular orbit of 460 x 460 miles (750 x 750 km), inclined 52 degrees to the equator, and will remain in service for at least five years to provide two-way messaging services for global customers. Each satellite weighs 380 pounds (172 kg) and, when fully deployed in orbit, will measure 42.7 feet (13 meters) x 3.3 feet (1 meter) x 1.6 feet (0.5 meters) and generate about 400 watts of electrical power.
Following a failed inaugural OG-2 launch in October 2012, the six satellites were all built by Sierra Nevada Corp. (SNC). Another eleven OG-2 satellites—which are currently undergoing final processing at SNC—are expected to fly aboard another Falcon 9 v1.1 later this year.
Orbcomm announced in May 2008 that SNC would build a total of 18 satellites for a fee of $117 million, with an option for up to 30 others. A few weeks later, Orbcomm selected Argon ST, a subsidiary of Boeing, to develop advanced communications payloads to increase subscriber capacity by up to 12 times over earlier satellites, as well as transmitting data at higher speeds and quantities. Designed with Automatic Identification System (AIS), it is expected that the OG-2 network will be marketed by Orbcomm to U.S. and international coast guards and government agencies, as well as private security and logistics companies.
At the time of writing, 45 Orbcomm satellites have been delivered into orbit since July 1991, aboard a wide range of vehicles, including Europe’s Ariane 4, the air-launched Pegasus booster, Orbital Sciences Corp.’s Taurus, China’s Long March 4B, India’s Polar Satellite Launch Vehicle (PSLV), and Russia’s Cosmos-3M. Initial “Concept Demonstration Satellites” led to the OG-1 network and a replenishment series of “Quick Launch” missions, with the OG-2 series intended to supplement and eventually replace the first generation. “Due to their high efficiency and modular design, these satellites have substantially more capacity to service a larger number of subscribers, thus making the network more efficient with few satellites than the OG-1 satellites that are currently in orbit,” explained Pat Remias, SNC’s Space Systems senior director of programs. “SNC has established a satellite production line in our Louisville facility to integrate and test each vehicle rapidly, with up to six satellites processing simultaneously.”
This will be the fifth flight of SpaceX’s upgraded Falcon 9 v1.1 rocket, which undertook its maiden voyage in September 2013. Since then, it has also lofted its first two satellites into 22,000-mile (35,000-km) geostationary orbits: SES-8 last Dec. and Thaicom-6 last Jan. All three of those launches helped SpaceX recently clear a major hurdle in the company’s efforts to earn Air Force certification for the right to compete for big-money government launch contracts.
The OG2 launch is also expected to add further data points to SpaceX’s much-publicized plan to make the Falcon 9 v1.1 fully reusable and capable of returning to a soft touchdown on land. During the CRS-3 ascent, the rocket’s first stage performed a propulsive return-over-water “burn” and deployed its four landing legs to execute a “soft” splashdown in the Atlantic Ocean. Despite a 40-percent probability of success and the added risk of rough seas, the attempt went well and the first stage landed safely and vertically. Significantly, the excessive and uncontrollable roll motions which foiled the first soft-splashdown attempt during the Falcon-9 v1.1’s maiden flight in September 2013 were notably absent, with recorded roll rates close to zero. “Data upload from tracking plane shows first-stage landing in Atlantic was good,” tweeted SpaceX CEO Elon Musk. “Flight computers continued transmitting for 8 seconds after reaching the water. Stopped when booster went horizontal. Several boats en-route through heavy seas … ”
Although a touchdown on land is not yet planned, SpaceX hopes to continue refining its capability to touch down on water to gradually mature the capability. During Saturday’s OG-2 launch, shortly after the burn-out and separation of the first stage, it will execute a maneuver with its cold-gas attitude-control system to establish an “engine-forward” orientation. Three of the nine Merlin-1Ds will briefly fire to effect braking during the re-entry process, and the four landing legs will be deployed using high-pressure helium once in atmospheric flight. The legs span 60 feet (18 meters) when fully deployed, and the entire assembly weighs about 4,400 pounds (2,000 kg). Assuming that the vehicle does not fall victim to excessive roll motions, the center Merlin-1D will ignite shortly before it makes a gentle impact with the Pacific Ocean.
After having conducted a successful customary practice countdown and static hot-fire test of the launch vehicle on Friday, July 11, SpaceX is ready to try again for a fourth time Monday morning at 9:21 a.m. EDT. The launch window extends to 11:54 a.m. EDT. The 45th Space Wing’s official launch weather forecast call for a 70 percent chance of acceptable conditions expected at T-0, with the primary concerns being violations of the cumulus cloud, anvil cloud, and lightning rules, with weather deteriorating throughout the 2.5 hour launch window.
AmericaSpace is, as always, on-site at the Cape to provide coverage of the launch and will live stream SpaceX’s webcast via our launch tracker. Check back regularly for updates.
Report written by both AmercaSpace writers Mike Killian and Ben Evans.
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