SpaceX Dragon bound for space station with tons of cargo
Lighting up the night sky, a SpaceX Falcon 9 rocket streaked away from Cape Canaveral late Friday, sending an unpiloted Dragon cargo ship off on a three-day flight to the International Space Station while the booster's first stage flew itself back to an equally spectacular landing.
The launching marked the 20th and final flight under the company's original commercial resupply contract with NASA, a partnership that has delivered more than 94,000 pounds of equipment and supplies to the lab complex over the past eight years at a cost of roughly $3 billion.
The California rocket builder has a follow-on contract with NASA covering another half-dozen flights to the space station through 2024 using a cargo version of SpaceX's Crew Dragon astronaut ferry ship. The first launch under the Commercial Resupply Services 2 contract -- CRS-21 -- is targeted for late October.
The Falcon 9 rocket and cargo Dragon launched Friday took off from pad 40 at 11:50 p.m. EST, the moment Earth's rotation carried the Cape Canaveral Air Force Station launch pad into the plane of the station's orbit.
The rocket put on a dramatic show with the flaming exhaust from its nine first stage engines visible for dozens of miles around as it climbed out of the lower atmosphere. About two-and-a-half minutes later, the previously flown first stage fell away and the single engine powering the Falcon 9's second stage took over for the remainder of the climb to space.
The first stage, meanwhile, flipped around, re-ignited three engines to reverse course and headed back toward Cape Canaveral. Plunging earthward, invisible to spectators in the overnight sky, the rocket's center engine suddenly flared to life, four landing legs extended and the booster settled to a pinpoint touchdown on a SpaceX landing pad.
Company founder Elon Musk tweeted before launch that high winds would make the landing a challenge, but the rocket managed a stable, on-target descent. SpaceX's recovery record now stands at 50 successful landings, 31 on off-shore droneships, 17 at Cape Canaveral and two at Vandenberg Air Force Base in California.
About a minute-and-a-half after the first stage landing, the twice-flown Dragon capsule was released from the Falcon 9's second stage. If all goes well, the spacecraft will catch up with the space station early Monday. Capture by the lab's robot arm is expected around 7 a.m. EDT.
The Dragon is loaded with 4,358 pounds of crew supplies, science gear and equipment, including a European Space Agency external experiment platform known as Bartolomeo that will be mounted on ESA's Columbus laboratory module, spare parts for the station's urine recycling system, rodent habitat hardware and a variety of other experiments.
Also on board: an experiment by Delta Faucet that will take advantage of the weightless environment of space to study the physics of water droplets in hopes of improving shower heads.
"Our struggle in this area is that regulations continue to push the flow rates down ... because we know that water is a precious commodity that we have to use very wisely," said Paul Patton, principal investigator of the droplet formation study.
The goal of the research is to study the relationship between water droplet size and the momentum they carry to maximize the user experience while minimizing the amount of water required.
"Most people, if you ask what they want, they want more pressure," said Garry Marty, a product engineer who has been with Delta for nearly four decades. "It's not really pressure, it's the momentum in the droplet. And that's what we're controlling. We just want to try to maximize that potential as best we can to continue to give customers a good feel while using less water."
ESA's Bartolomeo platform, carried in the Dragon's unpressurized trunk section, will be pulled out by the space station's robot arm and locked in place on the forward side of the Columbus module. A spacewalk is tentatively planned for mid April to connect power and data lines.
Built by the European consortium Airbus, Bartolomeo will provide mounting points for up to 12 external experiments or sensors.
"Payload size can range from ... about the size of a loaf of bread up to about the size of a washer-dryer," said Kris Kuehnel, Airbus director of operations in Houston. "When you combine the flexibility of the payload sizes, the multiple locations, the multiple viewing angles, we're able to provide really the perfect platform to support activities such as Earth observation or technology development."
The Dragon capsule is expected to remain berthed at the Earth-facing port of the forward Harmony module for 28 days, departing on April 6. The Dragon is the only cargo ship currently flying that can bring significant amounts of hardware and experiment samples back to Earth. In SpaceX's 19 earlier CRS flights, some 74,000 pounds of material was brought down from the station.
Some 3,700 pounds of equipment and science samples are expected to be returned aboard the CRS-20 Dragon, including rodent habitats that will be refurbished, degraded carbon dioxide removal equipment and nitrogen/oxygen tanks that need to be serviced.
