Sierra Nevada Corp.
This artist's impression shows the Dream Chaser Cargo System concept in orbit above Earth.
With crews of three to six people to support, the International Space Station (ISS) has a tough job that it can't do all on its own. The facility depends on regular resupplies from Earth to carry food, water and equipment for the astronauts on board -- not to mention all the science experiments.PHOTOS: 'Space Invader' Found on International Space Station
However, in the past year, three separate programs have suffered failures to their resupply programs. But overall, the track record of the program has kept the ISS flying with people continuously since November 2000. On Wednesday (Aug. 19), the Japanese Space Agency (JAXA) launched their H-II Transfer Vehicle (HTV) on a 5-day mission to the ISS.
Let's take a tour of the space station's fleet of private and government-run resupply spaceships.
There were five European Automated Transfer Vehicles (ATVs) that carried supplies to orbit. They were capable of carrying dry cargo (such as hardware) and fluid cargo (such as station fuel) inside for transfer for the station. The pressurized section, which made up 90 percent of the cargo carrier, could be accessed by two astronauts for up to eight hours to allow ample time for unloading. The last ATV departed the station in February 2015 and broke up as planned in the atmosphere, laden with sensors. The intention is to design better cargo spacecraft in the future, ESA said at the time.PHOTOS: Astronauts Watch Spectacular Spacecraft Reentry
Cygnus is a spacecraft developed by private company Orbital Sciences Inc. under a Commercial Orbital Transportation Services contract from NASA. The spacecraft has made four attempts to reach the International Space Station since September 2013; the latest one, in October 2014, ended in an explosion due to a problem with the rocket that was carrying it. Cygnus "borrows" from the design of other products Orbital has created for spaceflight. For example, the service module has avionics, propulsion and power systems used in GEOStar communication satellites.MORE: Antares Rocket Explodes Moments After Liftoff
Like Cygnus, Dragon was also developed using NASA funding from the Commercial Orbital Transportation Services program. Out of nine resupply runs to the station, Dragon has made it safely all but once (in its latest attempt in June, due to a rocket failure.) The spacecraft can carry sensitive biological experiments such as mice or blood samples. It was the first to dock with the space station in 2012. SpaceX is now using a similar design to create a human-rated spacecraft that would fly no earlier than 2017.MORE: SpaceX Falcon 9 Rocket Explodes Minutes After Lift-Off
The H-II Transfer Vehicle (HTV) -- also known as Kounatori, which means "white stork" -- has now launched five times to the International Space Station since 2009. The fifth HTV cargo run is currently in progress having launched on Wednesday (Aug. 19) and due to arrive at the space station on Monday (Aug. 24).MORE: Japan Launches Critical Supplies (and Mice) to the ISS
The spacecraft includes a pressurized internal section for crew cargo or experiments, and an exposed pallet that carries experiments or spare parts to be mounted outside of station using the Kibo robotic arm. While the current HTV mission is the final launch under the JAXA-NASA agreement, NASA spokesperson Stephanie Schierholz told Discovery News that the agencies will add at least two more HTV flights -- more are possible as well.
Progress is by far the longest-running workhorse of space station cargo ships. Versions of the spacecraft have been in use in space since 1978. The Progress-M spacecraft has made nearly 60 flights to the ISS, carrying dry cargo as well as fuel to the orbiting complex. In recent years, a Progress was lost in 2011 due to a launch failure. Earlier this year, a Progress made it to orbit but could not be controlled to direct it to the station.MORE: Doomed Russian Spaceship May Re-Enter Next Week
The space shuttle wasn't only a space station cargo ship, it also played a leading role in
the International Space Station. Crews of up to seven people could be accommodated in its cabin while not losing any space for cargo, which would ride in the back payload bay. Some of the major parts of the station hauled to orbit include the Unity Node (the first U.S. part of the station), the Cupola viewing windows, the Joint Airlock and the robotic Canadarm2 that is used to assist astronauts during spacewalks. The shuttle was retired in 2011.PHOTOS: Inside Atlantis' Final Space Station Mission
After losing a bid to SpaceX and Boeing to taxi astronauts to the International Space Station, Sierra Nevada’s miniature space shuttle Dream Chaser will have a new mission -- flying cargo for NASA.
“It’s pretty emotional. We’ve been chasing this for a long time,” corporate vice president Mark Sirangelo, head of Sierra Nevada’s Space Systems, told Discovery News.
The space agency also re-hired SpaceX and Orbital ATK, which currently fly cargo to the station. Each company’s contract covers at least six cargo runs to the station between 2019 and 2024.
The Dream Chaser Cargo System builds on the mini-space shuttle design Sierra Nevada has been working on for a decade, including four years with NASA backing.
The robotic version of Dream Chaser features foldable wings so the spaceship can fit inside standard 5-meter payload fairings, used by United Launch Alliance’s Atlas 5 rocket, the baseline vehicle for the cargo resupply missions, as well as Arianespace’s Ariane booster.
The Dream Chaser freighter also includes a detachable piggyback cargo module that will be discarded during atmospheric re-entry. Equipment and experiments samples inside the spaceship can be quickly retrived once the vehicle makes its airplane-like landing on a runway.
“We’re home within eight- to 10 hours and we’re off-loading within 30 minutes of landing,” Sirangelo told Discovery News in an interview last year.
Dream Chaser can carry up to about 44,000 pounds of cargo inside the vehicle and another 4,400 pounds of unpressurized cargo in four flights per year, exceeding NASA’s delivery requirement by about 11,000 pounds per year.
The cargo version of Dream Chaser also can discard trash and return cargo, giving NASA more options. SpaceX’s Dragon capsules make parachute splashdowns in the Pacific Ocean, while Orbital’s Cygnus capsules burn up during atmospheric re-entry. Dream Chaser is the only vehicle that lands on a runway.
“We believe that it’s the best cargo system that currently exists or will exist, because it’s capable of meeting all of NASA’s cargo requirements in the same system,” Sirangelo told reporters at an industry trade show last year.
Sierra Nevada had proposed a crewed version of Dream Chaser under NASA’s Commercial Crew program. The space agency opted for a passenger version of SpaceX’s Dragon capsule and a new offering from Boeing called the CST-100 Starliner. The vehicles are expected to begin transporting crew in 2017.