April 18, 2014
– A commercial space freighter loaded with more than two tons of scientific experiments and supplies launched for the International Space Station Friday (April 18), after more than a month of delays.
Space Exploration Technologies (SpaceX) Dragon capsule lifted off on a Falcon 9 rocket, also built by the company, at 3:25 p.m. EDT (1925 GMT) from Launch Complex 40 at the Cape Canaveral Air Force Station in Florida. Rain and low clouds earlier in the day threatened a scrub due to the weather, but conditions improved such that the flight could proceed.
Other than apparently some soiled water splashing on the Falcon 9 as it left the pad, the launch went smoothly, Elon Musk, SpaceX CEO and chief designer, told reporters.
"Everything looks great as far as the ascent phase of the mission," he said. "The rocket flight was perfect as far as we can tell."
SpaceX's Falcon 9 rocket soars skyward from Launch Complex 40 at Cape Canaveral Air Force Station, April 18. (collectSPACE)
Ten minutes into the flight, the Dragon separated from the Falcon's second stage to begin its two-day journey to the space station. According to Musk, there was a brief issue with some of the craft's maneuvering thrusters, which he said traced back to a stuck isolation valve.
"We had some slight, initial challenges with Dragon with respect to enabling some of the thruster quads, but those have been resolved," he said. "So, it looks like everything is good on the Dragon front."
The gumdrop-shaped spaceship is scheduled to arrive at the space station on Sunday morning, where the outpost's crew will use the Canadarm2 robot arm to grab hold of and attach the Dragon to the complex for a month-long stay.
The berthing had been planned for four days earlier, but a helium leak in the Falcon 9 rocket's first stage separation system resulted in SpaceX delaying its earlier attempt at launching on Monday. The scrub was among a series of issues that pushed the flight from March to April, and had NASA juggling the launch and an unplanned spacewalk.
Up and out (or out and up)
Even prior to the helium leak being discovered, Monday's launch attempt had been called into question by the failure of a back up computer component mounted to the outside of the space station.
The faulty router, referred to as a multiplexer demultiplexer (MDM), normally offers the redundancy for the control and monitoring of the outpost's external systems, including the mobile transporter rail car and the joints used to angle the station's electricity-generating solar arrays.
A rainbow extends from behind SpaceX's Dragon-capped Falcon 9 rocket at Cape Canaveral Air Force Station's Launch Complex 40 in Florida on April 14, 2014. (collectSPACE)
Despite the failed MDM, NASA's mission managers made the decision to press ahead with the SpaceX launch, while also scheduling a spacewalk to replace the failed box. To protect against the unlikely situation that the primary MDM might fail before the Dragon arrived, the mobile transporter was positioned prior to Monday's launch attempt and after Friday's liftoff, the solar arrays were to be reoriented to the angles needed during the capsule's rendezvous.
With the Dragon now on its way, the spacewalk has been scheduled for Wednesday (April 23).
The start of SpaceX's fourth trip to the space station had initially been slated for March 16. The flight, referred to as Commercial Resupply Services 3 (CRS-3), ran into its first delay after an oily substance was found contaminating the Dragon's trunk section, which could have damaged optical experiments stowed there for delivery to the station.
As SpaceX worked to resolve that concern, a radar station required to track the launch was knocked offline by a short circuit on March 24. The U.S. Air Force needed two weeks to restore the radar, and then SpaceX had to wait for both a Russian Progress resupply ship to dock with the station on April 9 and a National Reconnaissance Office satellite to launch the next day.
SpaceX's mission patch for its third Dragon resupply flight to the International Space Station, CRS-3, on April 14, 2014. (SpaceX)
CRS-3 is SpaceX's third Dragon mission under a 12-flight, $1.6 billion contract with NASA to fly supplies to and from the space station. The Hawthorne, Calif.-based company's Dragon spacecraft is the only cargo ship currently flying to the outpost that is capable of returning experiment results and other equipment to Earth.
At the end of its month-long stay at the space station, the Dragon will reenter the atmosphere and make a parachute assisted splashdown off the coast of southern California.
First though, the Dragon needs to arrive at the station and be unpacked of its cargo. The craft was loaded with about 4,600 pounds (2,100 kilograms) of supplies and equipment to support the more than 150 investigations that will occur during the station's 39th and 40th expeditions.
Science, salad and spacesuit components
To support more science payloads, the CRS-3 Dragon has nearly four times the powered cargo capability of previous flights. The capsule was outfitted with additional freezers and for the first time, loaded with powered cargo inside its unpressurized trunk. The ship is also sporting redesigned cargo racks to accommodate the added instruments.
The mission's science payloads include NASA's Optical Payload for Lasercomm Science (OPALS), which will test the use of laser optics to transfer data back to Earth; the Vegetable Production System (VEGGIE), a device to grow salad-type vegetables on the space station; and the T-Cell Activation in Aging experiment that will seek the cause of a depression in astronauts' immune systems.
In addition, the CRS-3 Dragon includes four high-definition cameras to be installed on the station's exterior for use in streaming live video of Earth for online viewing as part of the High Definition Earth Viewing (HDEV) investigation.
Another experiment, Project MERCCURI, will measure the growth rate of microbes gathered at sport stadiums and off historic artifacts, including John Glenn's Mercury capsule, Friendship 7. The University of California, Davis project is the result of a partnership with NFL and NBA cheerleaders now pursuing careers in science and technology.
Dragon's payload also includes a new legs for the station's Robonaut 2 humanoid robot and spacesuit components to address earlier issues with water leaking into the helmets during spacewalks.
In addition to the Dragon, the Falcon 9 second stage also launched into orbit five small "CubeSat" satellites, as held inside four Poly Picosatellite Orbital Deployers (P-PODs).
The Falcon 9's first stage, after separating, also tested an experimental "soft landing" recovery procedure. According to SpaceX, the first stage re-fired its engines to slow and stabilize its descent, to then extend a set of four 25-foot-long (7.6 meter) legs, just before splashing down off the coast of northern Florida in the Atlantic Ocean.
The base of SpaceX's Falcon 9 is seen sporting new landing legs for an experimental recovery over the ocean. (collectSPACE)
Live telemetry from the stage suggested the descent went as planned, though ocean conditions may have prevented the stage's recovery.
"Data upload from tracking plane shows landing in Atlantic was good!" Musk wrote on Twitter about three hours after the launch. "Several boats enroute through heavy seas."
"Flight computers continued transmitting for eight seconds after reaching the water. Stopped when [the] booster went horizontal," he wrote.
SpaceX officials have said they hope to eventually return the Falcon's first stage to a land-based touchdown so that it may be reused.
"We are really starting to connect the dots," Musk stated. "There are only a few more dots that need to be there to have it work. I think we've got a decent chance of bringing a stage back this year, which would be wonderful."