It’s about that time again: the astronauts on the International Space Station are all set to get a new shipment of cargo from Earth. This time, it’s private spaceflight company Orbital ATK that’s in charge of the resupply run. The company’s Cygnus cargo capsule — filled with more than 7,600 pounds of food, water, tools, and science experiments — is set to launch on top of an Atlas V rocket from Cape Canaveral, Florida, this morning. The flight was supposed to happen at the end of March, but was delayed until today due to a hydraulic issues with some ground equipment.
This is Orbital’s third time launching the Cygnus on an Atlas V — the flagship rocket manufactured by the United Launch Alliance. Orbital has its own rocket, the Antares, which is also capable of sending the Cygnus to the station. However, Orbital couldn’t use the Antares for a while after one of the vehicles exploded just seconds into a launch in October 2014. The Antares was grounded for two years after that while the vehicle’s engines were replaced; the Atlas V served as a stopgap in the meantime so that Orbital could continue to resupply the station as part of its contractual obligations to NASA.
The Antares actually returned to flight in October of last year, performing a picture-perfect cargo resupply launch to the ISS. But despite that mission’s success, in November, NASA asked Orbital to return to the Atlas V for this launch since the rocket can get more weight into orbit. The agency was anxious to get as much weight to the station as possible after a few unexpected events affected the flow of supplies. For instance, SpaceX — NASA’s other commercial resupplier for the ISS — had to ground all flights from September 2016 to January of this year, when one of the company’s Falcon 9 rockets exploded during a fueling procedure on a Florida launchpad.
By switching to the Atlas, Orbital was able to add about 660 extra pounds to the Cygnus capsule, according to Frank Culbertson, a former astronaut and president of the space subsystems group for Orbital ATK. Orbital is trying to increase the amount of payload that the Cygnus can carry on both the Atlas and the Antares, and the company plans to launch its next mission on the Antares as early as this summer. But Orbital is fine with sending the Cygnus up on either vehicle, depending on what NASA needs, Culbertson said in a press conference yesterday. “We’re comfortable going either way,” he said. “Antares of course is an Orbital ATK vehicle, so we like flying on that. But we certainly appreciate the partnership with ULA.”
Today’s launch is particularly special for Orbital ATK since it honors astronaut John Glenn, the first American to orbit the Earth, who died in December at the age of 95. The Cygnus capsule has been named S.S. John Glenn and features a banner with Glenn’s portrait on the inside. The title is part of Orbital’s tradition of naming its cargo capsules after astronauts who have passed.
Along with some belated Easter baskets for the crew, the cargo also includes a number of key science experiments: one involves testing out a new antibody drug that could help make chemotherapy treatments more effective for cancer patients. Another is a new plant habitat that will support the growth of small flowering plants and other vegetation in zero G. It’s similar to the Veggie habitat system that was used to grow the first ever space lettuce eaten by astronauts. However, this new plant habitat will be much more self-sufficient, requiring less work by the crew.
The Cygnus is also carrying 38 small satellites known as CubeSats, many of which have been built by college students. CubeSats are standardized space probes that are typically not much bigger than a shoebox and are great for doing small-scale research in space. These tiny vehicles will either be deployed into space from the station or from the Cygnus capsule itself in the upcoming months, according to NASA.
Normally it takes two to three days for cargo vehicles to meet up with the ISS, but the Cygnus is actually going to hang out in orbit for a little while once it launches. That’s because a pair of astronauts are scheduled to launch early Thursday morning on a Russian Soyuz rocket. So the Cygnus will stay out of the way until the incoming crew is safely onboard the ISS. Then on Saturday morning, NASA astronaut Peggy Whitson and Thomas Pesquet of the European Space Agency will grab the capsule with the station’s Canadian robotic arm and install it on the ISS.
The Cygnus is slated to stay at the station until July, when it’ll be loaded up with trash, detach, and hang out in orbit again. At that point, Orbital will light a large fire inside the vehicle again — the third time this has been done in a departing Cygnus to study how flames behave in microgravity. Once that experiment is complete, the capsule will take a dive into Earth’s atmosphere, where it will completely burn up.
But first, the capsule just has to get to the station. Takeoff is scheduled for 11:11AM ET today from Cape Canaveral Air Force Station, though the Atlas V can take off up until 11:41AM ET. So far, weather is looking good for launch; there’s a 90 percent chance that conditions will be favorable, according to Patrick Military Air Force Base. Those looking to watch the mission live will get an extra special treat this time around: the launch will be the first one to ever be live-streamed in 360 degrees. So you can feel like you’re there without actually enduring the Florida heat.