An Atlas V 401 rocket, carrying Orbital ATK’s S.S. Rick Husband Cygnus spacecraft, flies from Space Launch Complex 41at 11:05 p.m. EDT (03:05 GMT on Wednesday, March 23) with the OA-6 cargo resupply mission to the International Space Station. Photo Credit: Jacques van Oene / SpaceFlight Insider
CAPE CANAVERAL, Fla. — A ULA Atlas V rocket, in the 401 configuration, caused windows to rattle and car alarms to go off for miles around the Space Coast as the booster and S.S. Rick Husband Cygnus spacecraft ferried an estimated 7,756 lbs (3,518 kg) of cargo on its way to the International Space Station – the largest payload the spacecraft has sent aloft so far.
Orbital ATK and United Launch Alliance sent the fifth mission – under the $1.9 billion Commercial Resupply Services contract Orbital ATK has with NASA – on its way in spectacular fashion in the late evening hours of Tuesday, March 22.
This was the second, and final, planned launch of the Cygnus spacecraft atop a ULA Atlas V 401 rocket from Cape Canaveral. Photo Credit: Jared Haworth / We Report Space
The mission got underway promptly at 11:05 a.m. EDT (03:05 GMT), at the very opening of a 30-minute launch window. The weather conditions at the Cape simply could not have been more ideal. Mostly clear skies and a light breeze welcomed the Atlas V and its precious cargo as the rocket left the launch pad and slowly climbed into the moonlit skies above SLC-41.
“Today’s successful launch continues our great progress and momentum under the CRS contract with NASA,” Frank Culbertson, President of Orbital ATK’s Space Systems Group said via a release issued by the company. “I applaud the numerous professionals at NASA, ULA and Orbital ATK for their hard work and dedication. While we are still early in this mission, everything is tracking well. We now eagerly await Cygnus’ berthing with the ISS and conducting scientific experiments onboard the spacecraft for the first time.”
Forecasts had predicted a 90 percent chance of favorable launch conditions – by liftoff, it was clear that those conditions had reached 100 percent. Chilly temps had crept into the area yesterday, with highs only reaching the mid-60s during the day. That trend continued throughout today.
As noted, Tuesday’s launch was watched over by a full Moon, the light from which was unfettered by a smattering of clouds.
While concerns about cumulus clouds had been raised, the Launch Readiness Review cleared the Atlas V booster to be rolled from the adjacent Vertical Integration Facility (VIF) to SLC-41 on Monday, March 21, with the booster traversing the short distance between the two structures starting at 10 a.m. EDT (14:00 GMT).
The cargo for this mission included an array of science experiments. Technology demonstrators such as Gecko Grippers to look into how artificial gecko setae (the hairs on the small reptiles’ feet) could aid robots sent on orbit or to distant planetary destinations.
The Additive Manufacturing Facility or “AMF” is being launched on behalf of California-based Made in Space to serve as a permanent platform at the space station from which to print parts, experiments, and other needed items that would otherwise require a separate launch to get to orbit.
Strata-1, meanwhile, will focus more on the physical locations that astronauts might be sent to such as an asteroid, the Moon, and Mars. Various regolith simulators will help researchers gain a better understanding of how actual regolith behaves in the microgravity environment.
After about 55 days, with its cargo transferred to the ISS and it has been unberthed from the orbiting laboratory, Cygnus will spend an additional eight days on orbit. During this time, scientists will conduct the Saffire-1 experiment. Contained within its own compartment and away from the used experiments, waste, and trash that the Expedition 47 and 48 crews will have loaded the Cygnus spacecraft with, the experiment will ignite the largest purposely-set fire on orbit that has been lit today. It is hoped the experiment will provide a better understanding of flame propagation on orbit.
The Atlas V booster is well-suited to handle sending Cygnus to orbit as the rocket is described as having the ability to send some to 21,600 lbs (9,800 kg) low-Earth orbit and 10,470 lbs (4,479 kg) to a geostationary transfer orbit. The rocket was launched for the first time on Aug. 31, 2002; the 401 configuration of the rocket has flown 31 times since then.
The March 22 launch was greeted by a full Moon. Photo Credit: Michael Seeley / We Report Space
Shortly after it left the pad, the Atlas V booster conducted a pitch, yaw, and roll maneuver so as to maintain the correct ascent profile as well as to minimize aerodynamic loads on the vehicle.
One minute and twenty-three seconds into the flight Atlas was traveling Mach 1 – the speed of sound. Eleven seconds later and the vehicle entered the region of maximum dynamic pressure or “max-Q”. At this part of the flight, the rocket’s speed along with the density of the atmosphere conspired with one another to place the rocket and its precious cargo under the greatest amount of stress.
At booster engine cutoff (BECO), the RD-180 was burning its fuel of RP-1 (a highly refined form of kerosene) and liquid oxygen at the impressive rate of about 1,350 lbs per second – and moving at a speed of 10,000 miles (16,093 kilometers) per hour.
At this point in the flight, the rocket and payload were some 80 miles in altitude (Atlas was about 170 miles down range).
Four-and-a-quarter minutes after it had left the pad at SLC-41, Booster Engine Cutoff took place, with separation between the first stage and the Centaur upper stage taking place about six seconds after that.
A little more than four-and-a-half minutes into the flight, the first burn of the Centaur upper stage (MES-1) took place. The burn lasted approximately 37 seconds, ending at 18 minutes and nine seconds after liftoff.
Having completed its primary mission of shielding Cygnus through Earth’s atmosphere, the Payload Fairing or “PLF” was jettisoned some eight seconds later.
About a second-and-a-half under 21 minutes after it had left the pad far below, the S.S. Rick Husband separated from Centaur, unfurled its two solar arrays and began the final leg of its journey to the ISS.
“This was our second mission on an Atlas V rocket after our very successful OA-4 mission which we launched last December,” Orbital ATK’s Vice President of Advanced Programs in the Space Systems Group at Orbital ATK, Frank DeMauro told SpaceFlight Insider. “The Cygnus team has been very busy with both tonight’s mission, as well as the return-to-flight on Antares for this summer, 2016.”