How to Capture a Dragon in Space

André Kuipers during training with Canadarm2 (Credit: ESA/NASA)

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With the upcoming historic launch of the SpaceX Dragon capsule to the International Space Station, astronauts in orbit have been getting ready for the first commercial spacecraft that will bring supplies to the station. Astronauts Don Pettit and André Kuipers will be manually capturing and berthing the Dragon capsule, using the ISS’s Canadarm2. Originally, current station commander Dan Burbank was to be the main arm operator, but with the delay in Dragon’s launch (it was originally scheduled for February 2012), Burbank will already be back on Earth by the time Dragon reaches the station, currently scheduled for May 3. So now, Pettit and Kuipers have had to take over the duties and learn their new jobs while in space. Without the high-tech simulators that NASA has at Johnson Space Center, how do the astronauts prepare and practice for this important event?

“We have a really neat capability here on Station,” Pettit said during a press conference last week. “I have it set up all the time, so I wake up in the morning and have a bag of coffee in my mouth and a cinnamon scone in one hand and flying the simulator with the other.”

The crew actually has two ways to practice for Dragon’s arrival.

“One is actually flying (practicing with) the Canadarm, which is the world’s best trainer,” Pettit said, “and then on station we have two space station computers which double as an Arm simulator, and it has a full set of the Arm hand controllers – the setup, which we call Robot allows us to fly track and capture trajectories just as if we were in the simulators in Houston.”

Initially Burbank would have been the main arm officer, with Pettit and Kuipers assisting. Now, Pettit and Kuipers will have to complete the task themselves, with the two of them doing all the things that the three of them were originally trained to do.

For the capture and berthing, Pettit and Kuipers will be in the Cupola, with Pettit as prime operator and Kuipers as second arm operator. “We will have arm operation in the (Destiny) lab as a ‘hot backup’ just in case of contingencies, and we can activate it there if needed.”

The two astronauts will use the Station’s Canadarm2 to first grab the spacecraft and then maneuver it into place to mate with the Harmony module’s Earth-facing docking port.

Pettit said the on-orbit training has been invaluable. “It is really good to have that type of capability,” he said.

The following animation from the Canadian Space Agency shows just how complex it is to capture a Dragon in space.

SpaceX’s launch and Dragon’s arrival will be the premiere test flight in NASA’s new strategy to resupply the ISS with privately developed rockets and cargo carriers under the Commercial Orbital Transportation Services (COTS) initiative. Even though it is technically a est flight, NASA isn’t about to pass up an opportunity to send supplies to the station. Dragon will carry about nearly 521 kg (1,150 pounds) of cargo, mainly food and some spare parts for the ISS. When Dragon departs, the station crew will load nearly 680 kg (1,500 pounds) of cargo to be sent back to Earth, since the Dragon capsule won’t burn up in the atmosphere like other supply ships — it will be recovered in the ocean.

SpaceX Test Fires SuperDraco Abort Engines Critical To Astronaut Launch Safety

SpaceX test-fires its SuperDraco engine that powers the manned Dragon spacecraft launch escape system critical for Astronaut safety during launch to orbit. Credit: SpaceX

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Space Exploration Technologies (SpaceX) has test fired a prototype of its new SuperDraco engine that will be critical to saving the lives of astronauts flying aboard a manned Dragon spacecraft soaring to orbit in the event of an in-flight emergency.

The successful full-duration, full-thrust firing of the new SuperDraco engine prototype was completed at the company’s Rocket Development Facility in McGregor, Texas. The SuperDraco is a key component of the launch abort system of the Dragon spacecraft that must fire in a split second to insure crew safety during launch and the entire ascent to orbit.

The Dragon spacecraft is SpaceX’s entry into NASA’s commercial crew development program – known as CCDEV2 – that seeks to develop a commercial ‘space taxi’ to launch human crews to low Earth orbit and the International Space Station (ISS).

The engine fired for 5 seconds during the test, which is the same length of time the engines need to burn during an actual emergency abort to safely thrust the astronauts away.

Watch the SpaceX SuperDraco Engine Test Video:

Nine months ago NASA awarded $75 million to SpaceX to design and test the Dragon’s launch abort system . The SuperDraco firing was the ninth of ten milestones that are to be completed by SpaceX by around May 2012 and that were stipulated and funded by a Space Act Agreement (SAA) with NASA’s Commercial Crew Program (CCP).

“SpaceX and all our industry partners are being extremely innovative in their approaches to developing commercial transportation capabilities,” said Commercial Crew Program Manager Ed Mango in a NASA statement. “We are happy that our investment in SpaceX was met with success in the firing of its new engine.”

Dragon will launch atop the Falcon 9 rocket, also developed by SpaceX.

SpaceX test-fires its SuperDraco engine that will eventually power the manned Dragon spacecrafts launch escape system critical for Astronaut safety during launch to orbit. Credit: SpaceX

“Eight SuperDracos will be built into the sidewalls of the Dragon spacecraft, producing up to 120,000 pounds of axial thrust to quickly carry astronauts to safety should an emergency occur during launch,” said Elon Musk, SpaceX chief executive officer and chief technology officer in a statement. “Those engines will have the ability to deep throttle, providing astronauts with precise control and enormous power.”

“Crews will have the unprecedented ability to escape from danger at any point during the launch because the launch abort engines are integrated into the side walls of the vehicle,” Musk said. “With eight SuperDracos, if any one engine fails the abort still can be carried out successfully.”

SuperDraco engines will power the launch escape system of SpaceX’s Dragon. Eight SuperDraco engines built into the side walls of the Dragon spacecraft will produce up to 120,000 pounds of axial thrust to carry astronauts to safety should an emergency occur during launch. Credit: SpaceX

SpaceX is one of four commercial firms working to develop a new human rated spacecraft with NASA funding. The other firms vying for a commercial crew contract are Boeing, Sierra Nevada and Blue Origin.

“SuperDraco engines represent the best of cutting edge technology,” says Musk. “These engines will power a revolutionarylaunch escape system that will make Dragon the safest spacecraft in history and enable it to land propulsively on Earth or another planet with pinpoint accuracy.”

The privately developed space taxi’s will eventually revive the capability to ferry American astronauts to and from the ISS that was totally lost when NASA’s Space Shuttle orbiters were forcibly retired before a replacement crew vehicle was ready to launch.

Because the US Congress slashed NASA’s commercial crew development funding by more than 50% -over $400 million – the first launch of a commercial space taxi is likely to be delayed several more years to about 2017. Until that time, all American astronauts must hitch a ride to the ISS aboard Russian Soyuz capsules.

This week the Russian manned space program suffered the latest in a string of failures when when technicians performing a crucial test mistakenly over pressurized and damaged the descent module of the next manned Soyuz vehicle set to fly to the ISS in late March, thereby forcing about a 45 day delay to the launch of the next manned Soyuz from Kazakhstan.

NASA announces Feb. 7 launch for 1st SpaceX Docking to ISS

SpaceX Dragon spacecraft approaches ISS on Test Flight set for Feb. 7, 2012 launch. During the SpaceX COTS 2/3 demonstration mission in February 2012, the objectives include Dragon demonstrating safe operations in the vicinity of the ISS. After successfully completing the COTS 2 rendezvous requirements, Dragon will receive approval to begin the COTS 3 activities, gradually approaching the ISS from the radial direction (toward the Earth), to within a few meters of the ISS. Astronauts will reach out and grapple Dragon with the Station’s robotic arm and then maneuver it carefully into place over several hours of operations. Credit: NASA / SpaceX.

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Make or break time for NASA’s big bet on commercial space transportation is at last in view. NASA has announced Feb. 7, 2012 as the launch target date for the first attempt by SpaceX to dock the firms Dragon cargo resupply spacecraft to the International Space Station (ISS), pending final safety reviews.

The Feb. 7 flight will be the second of the so-called Commercial Orbital Transportation Services (COTS) demonstration flights to be conducted by Space Exploration Technologies, or SpaceX, under a contact with NASA.

Several months ago SpaceX had requested that the objectives of the next two COTS flights, known as COTS 2 and COTS 3, be merged into one very ambitious flight and allow the Dragon vehicle to actually dock at the ISS instead of only accomplishing a rendezvous test on the next flight and waiting until the third COTS flight to carry out the final docking attempt.

The Dragon will remain attached to the ISS for about one week and astronauts will unload the cargo. Then the spacecraft will depart, re-enter the Earth atmosphere splashdown in the Pacific Ocean off the coast of California.

“The cargo is hundreds of pounds of astronaut provisions,” SpaceX spokeswoman Kirstin Grantham told Universe Today.

SpaceX Dragon approaches the ISS
Astronauts can reach it with the robotic arm and berth it at the Earth facing port of the Harmony node. Illustration: NASA /SpaceX

“SpaceX has made incredible progress over the last several months preparing Dragon for its mission to the space station,” said William Gerstenmaier, NASA’s associate administrator for the Human Exploration and Operations Mission Directorate. “We look forward to a successful mission, which will open up a new era in commercial cargo delivery for this international orbiting laboratory.”

Since the forced retirement of NASA’s Space Shuttle following the final fight with orbiter Atlantis in July 2011 on the STS-135 mission, the US has had absolutely zero capability to launch either supplies or human crews to the massive orbiting complex, which is composed primarily of US components.

In a NASA statement, Gerstenmaier added, “There is still a significant amount of critical work to be completed before launch, but the teams have a sound plan to complete it and are prepared for unexpected challenges. As with all launches, we will adjust the launch date as needed to gain sufficient understanding of test and analysis results to ensure safety and mission success.”

SpaceX lofted the COTS 1 flight a year ago on Dec. 8, 2010 and became the first private company to successfully launch and return a spacecraft from Earth orbit. SpaceX assembled both the Falcon 9 booster rocket and the Dragon cargo vessel from US built components.

An astronaut operating the robot arm aboard the ISS will move Dragon into position at the berthing port where it will be locked in place at the Harmony node. Illustration: NASA /SpaceX

The new demonstration flight is now dubbed COTS 2/3. The objectives include Dragon safely demonstrating all COTS 2 operations in the vicinity of the ISS by conducting check out procedures and a series of rendezvous operations at a distance of approximately two miles and the ability to abort if necessary.

The European ATV and Japanese HTV cargo vessels carried out a similar series of tests during their respective first flights.

After accomplishing all the rendezvous tasks, Dragon will then receive approval to begin the COTS 3 activities, gradually approaching the ISS from below to within a few meters.

Specially trained astronauts working in the Cupola will then reach out and grapple Dragon with the Station’s robotic arm and then maneuver it carefully into place onto the Earth-facing side of the Harmony node. The operations are expected to take several hours.

The COTS Demo 2/3 Dragon spacecraft at Cape Canaveral. Photo: SpaceX

If successful, the Feb. 7 SpaceX demonstration flight will become the first commercial mission to visit the ISS and vindicate the advocates of commercial space transportation who contend that allowing private companies to compete for contracts to provide cargo delivery services to the ISS will result in dramatically reduced costs and risks and increased efficiencies.

The new commercial paradigm would also thereby allow NASA to focus more of its scarce funds on research activities to come up with the next breakthroughs enabling bolder missions to deep space.

If the flight fails, then the future of the ISS could be in serious jeopardy in the medium to long term because there would not be sufficient alternative launch cargo capacity to maintain the research and living requirements for a full crew complement of six residents aboard the orbiting laboratory.

Feb. 7 represents nothing less than ‘High Stakes on the High Frontier’.

NASA is all about bold objectives in space exploration in both the manned and robotic arenas – and that’s perfectly represented by the agencies huge gamble with the commercial cargo and commercial crew initiatives.

NASA Issues Report On Commercial Crew as SpaceX’s CEO Testifies About SpaceX’s Progress

NASA has released its third status report concerning the progress of the Commercial Crew Development program (CCDev). Photo Credit: SpaceX

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NASA has recently posted the latest update as to how the Commercial Crew Development 2 (CCDev2) program is doing in terms of meeting milestones laid out at the program’s inception. According to the third status report that was released by NASA, CCDev2’s partners continue to meet these objectives. The space agency has worked to provide regular updates about the program’s progress.

“There is a lot happening in NASA’s commercial crew and cargo programs and we want to make sure the public and our stakeholders are informed about the progress industry is making,” said Phil McAlister, NASA’s director of commercial spaceflight development. “It’s exciting to see these spaceflight concepts move forward.”

One of the primary objectives of the Commercial Crew Development program is to cut down the length of time that NASA is forced to rely on Russia for access to the International Space Station. Photo Credit: NASA

Reports on the progress of commercial crew are issued on a bi-monthly basis. The reports are directed toward the primary stakeholder of this program, the U.S. taxpayer. NASA has invested both financial and technical assets in an effort to accelerate the development of commercial access to orbit.

This report came out at the same time as Space Exploration Technologies’ (SpaceX) CEO, Elon Musk, testified before the U.S. House Science, Space, and Technology Committee regarding NASA’s commercial crewed program.

Elon Musk testified before the U.S. House Science, Space, and Technology Committee regarding his company's efforts to provide commercial access to the International Space Station. Photo Credit: SpaceX

SpaceX itself has been awarded $75 million under the CCDev program to develop a launch abort system, known as “DragonRider” that would enable the company’s Dragon spacecraft to transport astronauts. SpaceX was awarded $1.6 billion under the Commercial Orbital Transportation Services or COTS contract with NASA. Under the COTS contract, SpaceX must fly three demonstration flights as well as nine cargo delivery flights to the orbiting outpost. SpaceX is currently working to combine the second and third demonstration flights into one mission, currently scheduled to fly at the end of this year.

During Musk’s comments to the House, he highlighted his company’s efforts to make space travel more accessible.

“America’s endeavors in space are truly inspirational. I deeply believe that human spaceflight is one of the great achievements of humankind. Although NASA only sent a handful of people to the moon, it felt like we all went,” Musk said in a written statement. “We vicariously shared in the adventure and achievement. My goal, and the goal of SpaceX, is to help create the technology so that more can share in that great adventure.”

SpaceX's Falcon 9 launch vehicle is currently being readied for a liftoff date later this year. Photo Credit: Alan Walters/awaltersphoto.com

To date, SpaceX is the only company to have demonstrated the capacity of their launch vehicle as well as a spacecraft. The company launched the first of its Dragon spacecraft atop of its Falcon 9 rocket this past December. The Dragon completed two orbits successfully before splashing down safely off the coast of California.

NASA is relying on companies like SpaceX to develop commercial crew transportation capabilities that could one day send astronauts to and from the International Space Station (ISS). It is hoped that CCDev2 will help reduce U.S. dependence on Russia’s Soyuz spacecraft for access to the ISS. Allowing commercial companies to take over the responsibility of sending crews to the ISS might also allow the space agency focus on sending astronauts beyond low-Earth-orbit for the first time in four decades.

SpaceX's Dragon spacecraft recently arrived at the firm's hangar located at Cape Canaveral Air Force Station's Space Launch Complex-40 (SLC-40). Photo Credit: Alan Walters/awaltersphoto.com

Here There Be Dragons: SpaceX’s Spacecraft Arrives at Launch Complex 40

The next Dragon spacecraft, the one that is set to launch to the International Space Station has arrived at Cape Canaveral Air Force Station's Space Luanch Complex 41 (SLC-41) for processing. Photo Credit: Alan Walters/awaltersphoto.com

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CAPE CANAVERAL, Fla – Space Exploration Technologies (SpaceX) welcomed a new guest to Space Launch Complex 40 (SLC-40) on Sunday – the next Dragon spacecraft that is set to launch later this year. Members of the media were invited to a photo opportunity to chronicle the Dragon spacecraft’s arrival which had been delayed a day due to issues with travel permits.

The Dragon that arrived on Sunday is destined to fly to the International Space Station (ISS). It will be the first time that a private firm docks with the space station. The COTS Demo 2 Dragon was shipped from SpaceX’s facilities in Hawthorne, California to Cape Canaveral in Florida.

SpaceX's next Dragon spacecraft, the one set to fly to the International Space Station, was delivered to Cape Canaveral Air Force Station's Space Launch Complex 40 on Sunday. Photo Credit: SpaceX

The Falcon 9 rocket, with its Dragon spacecraft payload, is currently scheduled to launch from Cape Canaveral Air Force Station’s SLC-40 on Dec. 19. If all goes as it is currently planned the Dragon will maneuver along side of the orbiting laboratory where the space station’s robot Canadarm 2 will grapple the unmanned spacecraft it and dock it with the station.

“When it comes to the launch day, NASA will determine that, we’re pushing to launch on Dec. 19, but the final “go” date is set by NASA and the range,” said SpaceX’s Vice-President for Communications Bobby Block. “We are currently working to conduct a wet dress rehearsal on November 21st.”

The Dragon spacecraft that is bound for the ISS will ride this Falcon 9 rocket to orbit. The launch date is tentatively set for Dec. 19. Photo Credit: Alan Walters/awaltersphoto.com

SpaceX recently passed a Preliminary Draft Review (PDR) of the Dragon’s Launch Abort System (LAS). This system, which pulls astronauts and their spacecraft to safety in case of some problem with the Falcon 9 launch vehicle, is unlike other systems of its type. Normal abort systems are essentially small rockets affixed to the top of the spacecraft (which is normally on top of the rocket). Not so with SpaceX’s design, dubbed DragonRider – it will be built into the walls of the spacecraft.

The reason for the difference in the abort system’s design is twofold. First, it will drive the costs down (Dragon is being developed as a reusable spacecraft) -whereas traditional abort systems are not capable of being reused. Secondly the system could one day be used as a potential means of landing spacecraft on other terrestrial worlds, such as the planet Mars.

SpaceX has been working with NASA to get the Dragon spacecraft ready for its historic mission. This will mark the first time that many of the systems have been used on an actual mission. Photo Credit: Alan Walters/awaltersphoto.com

This will mark the second demonstration flight that SpaceX will have flown to accomplish the objectives laid out in the Commercial Orbital Transportations Services or COTS contract. The $1.6 billion contract is an effort to ensure that needed cargo is delivered to the station safely and in a timely fashion.

SpaceX so far has launched two of its Falcon 9 rockets – both in 2010. The first flight occurred on June 4, 2010 with the second being launched on Dec. 8, 2010. It was on this second flight that SpaceX became the first private entity to launch a spacecraft into orbit and then safely recover it after it had successfully orbited the Earth twice. Before this only nations were capable of achieving this feat.

“This is very exciting, our last launch was about a year ago, so to have a fully-operational Dragon up-and-ready to make a historic docking to the International Space Station it’s terrifically exciting.” Block said.

SpaceX is working toward expanding the role of not only the Falcon 9 rocket - but the Dragon spacecraft as well. Photo Credit: Alan Walters/awaltersphoto.com

Sierra Nevada’s Dream Chaser to Conduct Drop Test Next Summer

Sierra Nevada Corporation is set to conduct a high-altitude free-flight test of the company's dream Chaser space plane as early as this summer. Image Credit: SNC

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It looks as though the efforts to get commercial space taxis off the ground – is succeeding. Sierra Nevada Corporation’s (SNC) “Dream Chaser” space plane is slated to conduct its first test flight as early as next summer. SNC is one of four companies that have had proposals selected by NASA under the Commercial Crew Development Program – 02 (CCDev2).

The test flight, what is known as a high-altitude free-flight test or “drop-test” will see Dream Chaser lifted high into the air, where the craft will then be released from its carrier aircraft and attempt an unmanned landing. During the course of this flight test program SNC will test out the space plane’s autoland and other capabilities.

The Dream Chaser space plane is derived from the HL-20 lifting body developed by NASA. Photo Credit: SNC

“Sierra Nevada Space Systems is honored to be awarded an additional $25.6 million by NASA as part of the second round of the Commercial Crew Development Program (CCDev2), bringing the total award to $105.6 million for this round of the competition,” said Mark Sirangelo, head of Sierra Nevada Space Systems. “As part of CCDev2, the Program has already completed four of the planned milestones, on time and on budget. The now thirteen CCDev2 milestones will culminate in a high-altitude free-flight test of our vehicle in the summer of 2012. ”

With NASA’s fleet of orbiters retired and being prepared to go on display in museums, NASA is dependent on the Russian Soyuz for access to the International Space Station (ISS). NASA currently pays Russia $63 million per seat for trips to the orbiting laboratory.

If all goes according to plan, the Dream Chaser could be one of many 'space-taxis' that would supply transportation services to the International Space Station. Image Credit: SNC

Many within both NewSpace and established space companies have stated their intent on reducing the amount of time that the U.S. is in such a position. NASA also has worked to assist companies that are working on CCDev2 to either meet or exceed their deadlines.
NASA is hopeful that these developments will allow the space agency to turn over transportation to the ISS to commercial firms by 2016.

In the case of SNC, NASA increased what the company was paid by an added $25.6 million. SNC had already been awarded $80 million as their part of the CCDev2 contract. After this boost in funding, SNC announced that the drop test would be held next summer.
The Dream Chaser design is based primarily off of the HL-20 lifting body design and is capable of carrying seven astronauts to orbit. Dream Chaser is designed to launch from Cape Canaveral Air Force Station located in Florida atop a United Launch Alliance (ULA) Atlas V 402.

Sierra Nevada Corporation is working steadily to test out and prove the Dream Chaser's various systems. Photo Credit: SNC

If everything goes according to how it is currently planned, the test flight will take place at either Edwards Air Force Base, located in California or White Sands Missile Range in New Mexico. Virgin Galactic’s WhiteKnightTwo will carry the Dream Chaser space plane aloft for the test. Virgin Galactic, another NewSpace firm, is based in the U.S. and owned by Sir Richard Branson.

The ISS is viewed by the U.S, and the 15 other nations involved with the project as a crucial investment and having only one way to send crew to and from the ISS as being unacceptable. Sierra Nevada’s Dream Chaser is joined by Space Exploration Technologies’ (SpaceX) Dragon spacecraft, Boeing’s CST-100 and Blue Origin’s as-yet unnamed spacecraft in the CCDev2 contract.

The Dream Chaser space plane atop a United Launch Alliance Atlas V rocket. Image Credit: SNC

SpaceX: Next Dragon to Launch No-Earlier-Than Dec. 19

SpaceX has announced that it will work to launch the next Falcon 9 rocket from Cape Canaveral Air Force Station in Florida no-earlier-than Dec. 19, 2011. Photo Credit: Alan Walters/awaltersphoto.com

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CAPE CANAVERAL, Fla – The launch date of the next Falcon 9 rocket with its Dragon Spacecraft payload has been announced to occur no-earlier-than Dec. 19. This will mean that it will have been over a year since the last time that the NewSpace firm launched one of its rockets.

“NASA is working with SpaceX on our technical and safety data for this mission while coordinating with its international partners to sort out a launch schedule once a definitive decision is reached on the next Soyuz flight to the International Space Station. As a result, we’ve submitted December 19th to NASA and the Air Force as the first in a range of dates that we would be ready to launch,” said Kirstin Brost Grantham SpaceX’s Communications Director. “We recognize that a target launch date cannot be set until NASA gives us the green light as well as the partners involved in the International Space Station program make a decision on when to continue Soyuz flights. Our flight is one of many that have to be carefully coordinated, so the ultimate schedule of launches to the ISS is still under consideration.”

At a speech at the National Press Club on Thursday, SpaceX founder and CEO Elon Musk also confirmed that the flight of Dragon will likely be delayed — perhaps until January — due to the failure of a Soyuz rocket carrying a Progress re-supply ship to the ISS on August 24, 2011.

“It actually will likely result in a delay to our launch to the ISS,” Musk said, “and NASA rightly wants to have the appropriate level of astronauts with the right training when we arrive, so it looks like January for the launch to space station, and that is contingent upon the Russians meeting the schedule they’ve currently stating.”

The Russian Space Agency has scheduled Progress launches on October 30, 2011, and January 26, 2012, with potential launches for the manned Soyuz-FG spacecraft on November 12 and December 20, 2011.

SpaceX's last launch of a Falcon 9 rocket, seen here, was on Dec. 8 and carried the first of the firm's Dragon spacecraft to orbit: Photo Credit: Alan walters/awaltersphoto.com

SpaceX last launched one of its Falcon 9 rockets on Dec. 8 of last year. That launch saw the first flight of the company’s Dragon Spacecraft, which completed two orbits before splashing safely down in the Pacific Ocean off the coast of California. This event marked the first time that a private entity had accomplished this feat. Up until that time only nations had sent and retrieved spacecraft from orbit.

Also during Musk’s speech on Sept. 29, he announced that SpaceX is developing the world’s first, fully-reusable rocket. Musk said that the development of this as-yet-unnamed rocket, if successful, would greatly reduce the cost of launching to orbit and open the doors to manned flights to Mars. But the SpaceX CEO cautioned that success was not guaranteed.

With the space shuttle fleet retired and being prepared for display in museums and tourist attractions, NASA is relying on many proposed commercial space taxis that, unlike the Dragon which has flown, have yet to be tested. Boeing, Sierra Nevada Corporation and Orbital Sciences Corporation all have proposed designs to ferry astronauts to and from low-Earth-orbit and the International Space Station.