Dragon spacecraft preps for ISS cargo mission

[American Patriot]

SpaceX scrambles to fix glitches with cargo ship

A SpaceX Falcon 9 rocket boosted a commercial cargo ship into orbit Friday, but company flight controllers faced problems with on-board thrusters that help up solar array deployment.

by William Harwood
March 1, 2013 9:05 AM PST

A SpaceX cargo ship loaded with more than a ton of spare parts, science equipment and crew supplies bound for the International Space Station thundered into orbit Friday, but trouble with the capsule's thrusters forced flight controllers to delay solar array deployment and replan an already complex rendezvous.


"It appears that although it achieved Earth orbit, Dragon is experiencing some kind of problem right now," John Insprucker, SpaceX's Falcon 9 product manager, said during a company webcast. "We'll have to learn about the nature of what happened. According to procedure, we expect a press conference to be held a few hours from now. At that time, further info may be available."


A few minutes later, SpaceX founder and chief designer Elon Musk said in a tweet from company headquarters in Hawthorne, Calif., that three of four maneuvering rockets were being inhibited by the on-board avionics and that company flight controllers were "about to command inhibit override."




A SpaceX Falcon 9 rocket carrying a Dragon supply ship loaded with more than a ton of supplies bound for the International Space Station climbs toward orbit after launch from the Cape Canaveral Air Force Station.


(Credit: NASA TV)


He then tweeted that solar array deploy was being held up until at least two thruster pods were successfully activated. The Dragon cargo ship can only function for about 15 hours on battery power alone, not long enough to carry out a successful space station rendezvous.


But SpaceX flight controllers were able to get a second thruster pod back on line and shortly before noon ET, Musk tweeted that both solar panels had been successfully deployed.


The Dragon cargo ship's Falcon 9 rocket, also built by Space Exploration Technologies, roared to life at 10:10 a.m. ET and majestically climbed away from launch complex 40 at the Cape Canaveral Air Force Station.


Trailing a torrent of flame from its nine Merlin 1C engines, the 157-foot-tall rocket launched almost directly into the plane of the space station's orbit, accelerating through low clouds on a trajectory paralleling the East Coast of the United States.


During the first operational SpaceX resupply flight last October, one of the booster's first stage engines suffered a combustion chamber rupture, prompting an early-but-safe shutdown. The other engines fired longer than planned to make up for the shortfall and the Dragon cargo ship was released into the intended orbit.


This time around, all nine engines appeared to work normally and the first stage fell away on time about three minutes after liftoff. The second stage, powered by a single Merlin engine, then continued the climb to space.


The nozzle of the Falcon 9's second stage Merlin engine glows as the rocket nears orbit.


(Credit: NASA TV)



Live television views from a camera mounted at the base of the second stage showed the engine nozzle glowing cherry red against the limb of the Earth as the rocket climbed toward orbit.


The second stage appeared to operate normally and another television camera showed the Dragon capsule as it was released from its booster about nine minutes and 46 seconds after liftoff.


The capsule's two solar arrays were expected to deploy about two minutes later, but that ended up being delayed almost a full orbit.


The Dragon spacecraft was released into an initially elliptical orbit with a high point of around 200 miles and a low point of around 120 miles. Assuming the thruster issue can be resolved to NASA's satisfaction, the spacecraft should be able to execute a complex series of rendezvous rocket firings to catch up with the space station for a normal rendezvous.


But flight controllers may have to replan a series of rendezvous rocket firings, which could affect how long it might take to catch up with the station.


At the moment of liftoff, the International Space Station was 253 miles above the Atlantic Ocean just east of New England. The flight plan called for the Dragon to pull up to within about 30 feet of the huge lab complex Saturday morning and then to stand by for capture.


At that point, station commander Kevin Ford, working at a robotics work station in the multi-window Cupola compartment, planned to use the lab's robot arm to grapple Dragon capsule around 6:30 a.m. Saturday.


The astronauts typically handle berthing chores, carrying out complex multi-joint maneuvers to move the captured spacecraft to its docking port on the Earth-facing side of the station's forward Harmony module.


But this time around, ground controllers at the Johnson Space Center in Houston were expected to take over, sending commands to remotely operate the arm through berthing to demonstrate their ability to carry out complex arm procedures and to give the astronauts a bit of a break during a very busy day.


The Dragon capsule is packed with some 2,300 pounds of equipment and provisions, including 178 pounds of crew supplies; 300 pounds of space station hardware, including replacement components for the lab's carbon dioxide removal system; and more than 700 pounds of science gear, including a pair of Glacier freezers and experiment components.


A spacewalk equipment handling fixture called a grapple bar is mounted in the Dragon capsule's unpressurized trunk section. The station's robot arm, again operated by flight controllers in Houston, will be used a few days after berthing to extract the grapple bar assembly and stow it on the station's exterior for future use.


Assuming a successful berthing, Ford and his crewmates plan to re-pack the capsule with 1.5 tons of no-longer needed gear, components that need refurbishment or failure analysis and experiment samples that are needed by scientists back on Earth.


The return manifest includes 209 pounds of crew equipment; 1,455 pounds of science gear, including a Glacier freezer and cold bags loaded with experiment samples; and 884 pounds of space station hardware.


The SpaceX Dragon capsule is the only space station cargo craft designed to bring cargo back to Earth, a critical capability that was lost when NASA's space shuttle fleet was retired in 2011.


The manned Russian Soyuz spacecraft that carry three-person crews to and from the space station can only bring back a few hundred pounds of cargo. All other station vehicles -- unmanned Russian Progress supply ships and European and Japanese cargo craft -- burn up during re-entry.

[American Patriot]

SpaceX Struggles, But Remains On Track To Space Station

Comment Now Follow Comments




SpaceX's Falcon 9 rocket lifts off from Cape Canaveral on a mission to the International Space Station on March 1, 2013. (Image: NASA)



A privately-operated rocket mission to the International Space Station struggled after its launch on Friday morning, but is apparently back on track to deliver its hold full of supplies.


The CRS-2 supply mission, operated by Hawthorne, California-based SpaceX, lifted off successfully on a two-stage Falcon 9 rocket from Launch Complex 40 at the Cape Canaveral Air Force Station in Florida at 10:10 AM Eastern time.

Approximately 15 minutes after launch, an on-board Dragon spacecraft successfully separated from the rocket’s second stage, and was approaching the moment when its solar power arrays would deploy and the craft would proceed under its own power. But before that could happen, a spokesman on NASA’s live video feed of the launch announced that Dragon “appears to be experiencing a problem” and cut the feed.

Messages sent from the official SpaceX Twitter account and from Elon Musk’s personal account reassured observers that Dragon had separated successfully from the rocket, and was on its way to the ISS. But subsequent updates from Musk directly addressed a serious problem: “Issue with Dragon thruster pods. System inhibiting three of four from initializing. About to command inhibit override,” he tweeted. Later tweets indicated that the company was holding off on deploying the spacecraft’s solar arrays until it could get at least two thruster pods active.


Approximately 70 minutes after take-off, the vehicle passed over an Australian ground station that issued the override command; twenty minutes later Musk tweeted that the tank pressure in the craft’s thruster pod 3 was “trending positive,” and the company was preparing to deploy the solar arrays. Finally, at 11:49 AM, about 100 minutes after launch, Musk tweeted that solar array deployment was successful.


As of 12:00 PM Eastern time, the vehicle was in orbit and presumably on track to meet up with the International Space Station. SpaceX engineers continued to work on bringing the vehicle’s remaining two thrusters on line.


The Dragon space vehicle is filled with about 1,200 pounds of cargo for use on the ISS, including crew supplies and scientific materials for 160 different experiments planned for the station’s Expedition 34 crew. If all goes as planned, the vehicle will arrive at the ISS on March 2, where it will be grappled and connected to the complex for three weeks. During that time, astronauts will load about 2,300 pounds of cargo back on the ship, and then it will return to Earth on March 25, splashing down off the coast of Baja California.


SpaceX was started in 2002 by Elon Musk, a billionaire entrepreneur also known for founding PayPal and Tesla Motors. The company successfully developed its own launch vehicle, the Falcon 9 rocket, and its own spacecraft, called the Dragon. In 2008, NASA awarded contracts to deliver cargo to the International Space Station to SpaceX and Orbital Sciences Corporation; In 2010, SpaceX became the first privately funded company to successfully launch, orbit and recover a spacecraft.


Now that NASA’s officially retired its Space Shuttle fleet, SpaceX is contracted to perform twelve supply missions to the ISS; today’s mission was the second (the first occurred in October of last year). SpaceX is also a leading contender to provide crew transport to and from the ISS: In August 2012, the company was awarded $440 million in contracts to develop crew transport vehicles as part of NASA’s ongoing Commercial Crew Development program. Also in the mix: Sierra Nevada Corporation (which won $212.5 million in contracts) and Boeing ($460 million).