A SpaceX Falcon 9 rocket boosted a next-generation SpaceX cargo ship into orbit Sunday, the first in a new line of roomier, more capable Dragon capsules featuring many of the more advanced systems used by the company'sastronaut ferry ships.
Making the company's 21st supply run to the International Space Station — the first under a follow-on NASA contract — the new Cargo Dragon was loaded with more than 6,500 pounds of crew supplies, spare parts, science gear and other equipment, including a commercial airlock for on-board experiments.
Unlike the original Dragon cargo ship, which had to be captured by the space station's robot arm for berthing, the Dragon 2 is designed to fly itself all the way to docking at the same ports used by piloted Crew Dragon spacecraft. Unlike the crewed version, however, the cargo ship is not equipped with seats or an emergency abort system.
Running a day late because of bad weather, the long-awaited mission began at 11:17 a.m. EST when the Falcon 9's nine first stage Merlin 1D engines roared to life with a torrent of flame, pushing the 229-foot-tall rocket away from pad 39A at the Kennedy Space Center.
It was the 24th Falcon 9 launch so far this year, the 101st since the rocket's debut in 2010, the 21st SpaceX ISS cargo launch and the first for a Dragon 2 capsule.
Accelerating on 1.7 million pounds of thrust, the rocket quickly arced away to the northeast, climbing directly into the plane of the space station's orbit — a requirement for spacecraft trying to catch up and dock with a target moving at nearly 5 miles per second.
Two-and-a-half minutes after liftoff, now well out of the thick lower atmosphere, the first stage, making its fourth flight, fell away and flew itself to a landing on a downrange SpaceX droneship. It was SpaceX's 68th successful booster recovery and its 47th at sea.
The Falcon 9's second stage, meanwhile, continued the climb to space, releasing the Dragon 2 capsule into the planned preliminary orbit 12 minutes after launch. If all goes well, the capsule will rendezvous with the station Monday, guiding itself in for a docking at the upper port of the forward Harmony module around 1:30 p.m.
The space station is equipped with eight docking ports, four used by Russian spacecraft and four on the forward end of the lab that are available for U.S. cargo and crew ships. Two of the U.S. ports are used by visiting cargo ships that need the station's robot arm to pull them in for berthing.
The other two U.S. ports, however, are equipped with docking mechanisms that can accommodate automated linkups by SpaceX crew and cargo Dragons and Boeing's CST-100 Starlink crew ferry ship. The Crew Dragon spacecraft that carried four astronauts to the station last month is docked at Harmony's forward-most port while the Dragon 2 cargo ship will carry out the first docking at the module's upper space-facing port.
SpaceX won NASA contacts valued at $3.04 billion for 20 space station resupply flights through 2020 using the original Dragon cargo ship design and contracts for an unspecified amount covering at least nine additional flights through 2024 using the Dragon 2 spacecraft. The capsule launched Sunday is the first of those.
SpaceX also holds a $2.6 billion NASA contract to build and launch the piloted Crew Dragon capsule to ferry astronauts to and from the space station. So far, three Crew Dragons, two with astronaut crews and one without, have docked at the station.
For its maiden flight, the Dragon 2 cargo ship's pressurized cabin was loaded with 803 pounds of crew supplies; 2,100 pounds of science gear; 265 pounds of spacewalk equipment; 698 pounds of vehicle hardware; 102 pounds of computer equipment; and 53 pounds of Russian hardware.
Stored in the capsule's unpressurized trunk section was a 2,400-pound airlock developed by Nanoracks, a company that facilitates flights by private industry, university and government-sponsored experiments. The airlock will be attached to the Tranquility module's far left port and periodically detached, exposing experiments inside and mounted on its exterior to the vacuum of space.
The station already features a Japanese experiment airlock, but the Nanoracks unit, known as the Bishop Airlock, is about five times larger, said project manager Brock Howe.
"There are a lot of different environments that the scientists can use, a lot of different volumes, a lot of different payload power and data capabilities on board the airlock that really will enhance their ability to do some really cool science," he said.
Other equipment on board the Dragon 2 includes parts for the lab's recently delivered female-friendly next generation toilet, gear for the station's water recycling system, a nitrogen tank for cabin repressurization and a rodent habitat with research specimens.
Among the experiments being delivered are two designed to study how microgravity affects heart and brain tissue and another called "BioAsteroid" that will probe the role microbes might play in future space mining operations.
"BioAsteroid is an experiment to study whether we can use micro organisms, bacteria or fungi, to extract economically interesting elements from asteroid material," said principal investigator Charles Cockell, professor of astrobiology at the University of Edinburgh.
"It's essentially what we would call a bio-mining experiment, and we hope to learn whether we can use microbes to extract things like rare earth elements and other elements that can be used to sustain a self sustaining human presence throughout the solar system."