SpaceX set for supply run to space station on Monday
The launch of a SpaceX Falcon 9 rocket Monday to carry supplies to the International Space Station kicks off an exceptionally busy few weeks in space, with a Russian spacewalk on tap Thursday, a United Launch Alliance Atlas 5 flight Friday, the 40th anniversary of the Voyager program's first launch on Sunday and a coast-to-coast solar eclipse the next day.
SpaceX plans another launch, this one from Vandenberg Air Force Base, California, on August 24 to boost an Earth observation satellite into orbit for Taiwan, followed by the launch of a solid-fuel Orbital ATK Minotaur rocket from Cape Canaveral on August 25 carrying a military satellite.
Three space station crew members return to Earth on September 2. Then, another Falcon 9 -- this one carrying an X-37B Air Force space plane -- is expected to launch from Florida around September 7 and another ULA Atlas 5 is scheduled for takeoff September 11 to boost a classified military payload into space. The next day, three fresh space station crew members take off from the Baikonur Cosmodrome in Kazakhstan to boost the lab's crew back up to six.
The surge begins at 12:31 p.m. EDT (GMT-4) Monday when SpaceX launches its 39th Falcon 9 rocket, its ninth flight from historic pad 39A at the Kennedy Space Center and its 11th flight overall this year. Forecasters are predicting a 70 percent chance of good weather.
Mounted atop the slender rocket is a Dragon cargo ship loaded with more than 3 tons of cargo, supplies and research equipment bound for the International Space Station. Assuming an on-time launch, astronaut Jack Fischer, operating the station's robot arm, will snare the Dragon early Wednesday so it can be pulled in for berthing.
Because of the time needed to catch up with the station, limited shelf life for several on-board experiments and the Russian spacewalk Thursday, SpaceX will not have a second launch opportunity Tuesday. If the flight is delayed for any reason, it will slip to sometime after the Friday launch of the Atlas 5.
But with generally good weather expected, mission managers were optimistic about sending the Dragon on its way Monday.
"We've loaded Dragon with 6,400 pounds of cargo and I'm happy to say 75 percent of that total mass is headed toward our research community," said Dan Hartman, deputy manager of NASA's space station program. "It sets a new bar for the amount of research we've been able to get on this flight."
Packed away in the Dragon's pressurized cabin will be needed computer gear, crew food and clothing, station hardware, research equipment and test subjects (including 20 mice) on board as part of a project to learn more about the long-term effects of weightlessness.
Mounted in the Dragon's unpressurized trunk section is a 1.3-ton cosmic ray detection experiment known as CREAM -- Cosmic Ray Energetics and Mass -- that has logged 191 days aloft during earlier high-altitude balloon missions.
It will spend three years attached to the space station, flying 10 times higher than the balloons, to measure high-energy cosmic rays and how they trigger cascades of particles during collisions with atoms and molecules in the upper atmosphere.
"By utilizing the space station, we can increase our exposure by an order of magnitude," said Eun-Suk Seo, CREAM principal investigator at the University of Maryland. "Every day on the station we will increase the statistics, and the statistical uncertainties get reduced, and we can detect higher energies than before.
"It's a very exciting time for us in high-energy particle astrophysics, and the long development road of CREAM culminating in this space station mission has been a world-class success story."
Because the Dragon is bound for the space station's relatively low orbit, the Falcon 9's first stage will have enough propellant left over to attempt a landing back at the Cape Canaveral Air Force Station about eight minutes after launch.
SpaceX has successfully recovered 13 stages in 18 attempts, five at the Air Force station and eight aboard off-shore droneships. Monday's landing attempt will be the company's first since a droneship landing June 25.
But as with all SpaceX missions, landings are a secondary objective. The primary goal of the fight is to deliver cargo to the space station in SpaceX's 12th operational resupply mission.
With the Dragon berthed at the Earth-facing port of the forward Harmony module, space station commander Fyodor Yurchikhin and Sergey Ryazanskiy plan to float outside the complex Thursday, starting around 10 a.m., to manually deploy five small satellites and carry out routine inspections and maintenance on the Russian segment of the station.
Then on Friday, at 8:03 a.m., United Launch Alliance plans to launch NASA's $408 million TDRS-M communications satellite atop a powerful Atlas 5 rocket, the latest in a series of agency-operated relay stations used by a variety of science satellites, rockets and the International Space Station.
On Sunday, planetary scientists will celebrate the 40th anniversary of Voyager 2's launch, the first of two identical spacecraft that explored the outer solar system. Voyager 1 studied Jupiter, Saturn and the ringed planet's giant moon Titan, while Voyager 2 flew past Jupiter, Saturn, Uranus and Neptune. Both spacecraft are still sending back data as they leave the solar system and move into interstellar space.
Next Monday, Aug. 21, millions of Americans will enjoy a total solar eclipse, weather permitting, as the moon's shadow races from Oregon to South Carolina. Weather will not be an issue for the crew of the space station, who will see the sun partially eclipsed on three successive orbits.