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Artykuły o Dream Chaser
« dnia: Marzec 23, 2019, 06:52 »
Dream Chaser Clears Another NASA Review for Inaugural 2021 Launch
By Mike Killian, on March 22nd, 2019 [AS]


Sierra Nevada Corporation's Dream Chaser engineering test vehicle at NASA's Armstrong Flight Research Center. Photo Credit: NASA

America’s next ‘spaceplane’ recently cleared another key NASA review towards flight, checking off the next milestone on Sierra Nevada Corp’s (SNC) journey to launching their first Dream Chaser atop a ULA Atlas V rocket from Cape Canaveral Air Force Station, Florida in 2021.

The orbital vehicle for that first mission is now under construction, and the latest review, known as Integrated Review Milestone 5 (IR5), analyzed SNC’s performance of a variety of ground and flight operations, including development of the vehicle’s flight computers and software, mission simulator and Mission Control Center.




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SNC also performed cargo demonstrations using high fidelity mock-ups of the vehicle and its cargo module, showing loading and unloading time and efficiency, and when all was said and done NASA declared the SNC team is on track to operate Dream Chaser in advance of the first mission.

“This milestone is a great accomplishment for the team focused on operations development and demonstration. It shows we can operate the Dream Chaser from the ground, including getting critical science in and out of the vehicle,” said John Curry, CRS-2 program director within SNC’s Space Systems business area.

The company currently holds a multi-billion dollar Commercial Resupply Services (CRS-2) program contract with NASA to fly at least six missions to resupply the International Space Station (ISS) through the first half of the 2020s, and ultimately have their eyes set on eventual crew missions.




SNC put their test article through its first free flight Approach and Landing test, ALT-1, at Armstrong Flight Research Center, CA in 2013, and the test went about as good as SNC could have hoped for, until only two of its three landing gear deployed, causing the vehicle to skid off the runway and sustain minor structural damage.

The test article then conducted a Phase Two flight test campaign in 2017, which served as a bridge between previous work with NASA’s Commercial Crew Program and the latest vehicle currently under development for the cargo only missions.

The second free flight test flew with orbital avionics software too, the same which the autonomous Dream Chaser CRS-2 cargo variant will use on its ISS missions. In doing so, SNC earned direct certification credit from NASA, eliminating the need for an orbital flight test before operational CRS-2 missions; all the testing and certifications happen on the ground and within the atmosphere.





The testing not only aids development of the orbital cargo vehicles, but the crewed version as well. Both cargo and crew variants share an 85 percent commonality, and the cargo-version can actually be made crew ready if NASA needed it.

When NASA offers up another round of Commercial Crew contracts in the coming years, SNC will put in a bid for their crew-version Dream Chaser.

NASA gave SNC the ‘GO’ to begin full production of the first orbital vehicle in Dec 2018, after clearing a thorough Critical Design Review; the culmination of many years of design work, analysis and development testing.



SNC's cargo Dream Chaser artist rendering in low Earth orbit. Credit: SNC

Many critical parts of the orbital vehicle are already complete, built and being tested, including major structural components, thermal protection system tiles and avionics hardware, which are now being integrated into the orbital vehicle assembly at SNC’s Space Systems facilities in Louisville, CO.

The spacecraft itself was actually originally designed by NASA, who did a lot of research on the vehicle in the 80′ and 90’s, based off a Russian heritage design called the Bor 4. They did thousands of hours of work on it, including wind tunnel analysis, a lot of computational fluid dynamics analysis, they conducted simulations with it, created the control laws to fly it and had a lot of astronauts come in to try it.

When SNC decided to pick a vehicle they opted against a ‘clean sheet of paper’, and decided instead to use something NASA had already put a lot of effort and research into, taking the basic design and changing it slightly.



NASA’s HL-20 at NASA’s Langley Research Center. The left image shows the HL-20 in front of the hangar at Langley, the center image shows the HL-20 undergoing testing for forced oscillation in pitch, and the right image shows people going through a series of tests to simulate launch and landing attitudes, crew seating arrangements, habitability, ingress and egress, equipment layout, maintenance and handling operations and visibility requirements during docking and landing operations. Photos Credit: NASA

NASA was looking for a spacecraft to use as a return vehicle from the ISS, so the agency competed a couple of different designs for rescuing crews in case of an emergency. One design was the X-38, the other was the HL-20 – which is now the Dream Chaser. NASA eventually decided to choose the X-38, but after working on that for several years the X-38 was abandoned also, leaving astronauts to rely exclusively on the space shuttle and Russian Soyuz as the emergency vehicles for the ISS.

When the first Dream Chaser arrives in Florida, it will be processed at the Kennedy Space Center (KSC) Operations and Checkout Building (O&C), and will then be transported to nearby Launch Complex-41 on Cape Canaveral AFS for integration atop its ULA Atlas-V rocket, then launch with up to 5,500kg (~12,100lbs) of pressurized and unpressurized cargo.

It also has the capability to dock or berth to the ISS, based on the cargo onboard and customer’s wishes (NASA). For berthing missions the vehicle will utilize a grapple fixture, and robotic trajectory analysis has already been done to ensure it would work.



The cargo Dream Chaser atop its ULA Atlas-V rocket. Image Credit: SNC

The spacecraft can remain at the ISS for over 200 days, if needed, before having to leave back for Earth with up to 1,850 kg (~4,000lbs) of cargo. The spacecraft also provides approximately 3,400kg (~7,400 lbs) of disposal capability each mission via the cargo module, which burns up in the atmosphere after separation from the Dream Chaser before reentry.

KSC’s runway will serve as the primary landing location, for obvious reasons (next to launch site and processing facilities). However, the vehicle is capable of landing on really any runway at least 8,000 feet long, anywhere around the world, without requiring specialized equipment, and SNC has been looking into landing at commercial airports for some time, having launched their “Dream Chaser-Preferred Landing Site Program” program to work with spaceports and commercial airports to become designated landing sites for Dream Chaser.

With a propulsion system fueled by Nitrous Oxide and propane this also means immediate access to the spacecraft after landing, with only 10-20 minutes needed to exit the runway and keep conflicts with other aircraft using the same area to a minimum. For a nominal (planned) landing this might not mean much, but in an emergency abort (unplanned) scenario such quick access to Dream Chaser would allow other airport operations to proceed with minimal or no impact from the spacecraft’s unexpected arrival.



SNC technicians inspect the Dream Chaser engineering test article ahead of its second flight test program, expected to begin soon at Edwards AFB in California. Photo Credit: SNC

Dream Chaser would usually take 4-6 hours from ISS departure to touchdown, however SNC has stated previously that time could be narrowed to 2 hours, if needed in the event of an emergency.

Once back on the ground the vehicle will go back to the O&C, get looked over, and be readied for its next flight. Turnaround time between landing and next launch would be around 60 days, however there are a lot of other factors that go into turnaround times, such as whether or not the rocket is even ready. The Dream Chaser itself, says SNC, could be turned around in much less than 60 days, implying a flight rate annually of 4-6 missions per vehicle.


Source: https://www.americaspace.com/2019/03/22/dream-chaser-clears-another-nasa-review-for-inaugural-2021-launch/
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Odp: [AS] First Dream Chaser Gets its Wings and a New Name, 'Tenacity'
« Odpowiedź #1 dnia: Czerwiec 23, 2020, 23:05 »
First Dream Chaser Gets its Wings and a New Name, 'Tenacity'
By Ben Evans, on May 4th, 2020


Sierra Nevada Corp. (SNC) has formally named its Dream Chaser spacecraft system as “Tenacity”. Image Credit: SNC

Bad luck, it is said, follows on the heels of a ship with no name. And Sierra Nevada Corp. (SNC) has finally dispelled the specter of misfortune by officially naming its Dream Chaser vehicle as “Tenacity”. The spacecraft—which bears more than a passing resemblance to a scaled-down version of the now-retired Space Shuttle—was selected by NASA in January 2016 for the second-round Commercial Resupply Services (CRS2) contract to regularly restock the International Space Station (ISS).

“Tenacity is in SNC’s DNA,” said company president Eren Ozmen. “Every critical moment in SNC’s history of innovation has called for tenacity in overcoming challenges in order to support and protect explorers and heroes. As the nation faces this current challenge, we want this vehicle to be a beacon of hope that American ingenuity, and tenacity, will bring brighter days ahead.”




Dream Chaser was originally proposed as a candidate for NASA’s Commercial Crew Program. Video Credit: SNC/YouTube

And the name tenacity is indeed an apt one, for Dream Chaser’s journey from the drawing-board to real spacefaring hardware has been a tough and convoluted one. In development for almost two decades, having been publicly announced in September 2004, it was envisaged that the spacecraft would play a role in the Commercial Crew Program.

SNC originally proposed Dream Chaser to NASA’s Commercial Crew Development (CCDev) program and in August 2012 received $212.5 million to continue work on the spacecraft under the Commercial Crew integrated Capability (CCiCap), with hopes that it would launch atop a United Launch Alliance (ULA) Atlas V booster and deliver up to seven astronauts to the ISS. As circumstances transpired, Dream Chaser lost out to Boeing’s CST-100 Starliner and SpaceX’s Crew Dragon in September 2014 for the next-round Commercial Crew transportation Capability (CCtCap), a decision against which SNC mounted an ultimately unsuccessful challenge.



Dream Chaser landing, free-flight test 2. Photo Credit: NASA

However, in March 2015 SNC reinvented its ship as the Dream Chaser Cargo System to resupply the ISS in an uncrewed capacity and in January of the following year it was selected alongside SpaceX and Orbital ATK as winners of the CRS2 contract. Under the terms of the contract, SNC would fly at least six Dream Chaser missions between 2019 and 2024. Although physically identical to the crewed variant, it would feature an innovative and versatile foldable wing structure, enabling it to launch inside the payload fairing of both the Atlas V and other vehicles, including Europe’s Ariane 5.

SNC also revealed that Dream Chaser would be capable of transporting around 12,000 pounds (5,500 kg) of payloads, equipment and supplies to successive ISS expedition crews and returning to a gentle runway touchdown on the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC) in Florida. As such, Dream Chaser promises to become the world’s only non-capsule commercial spacecraft. In July 2017, SNC selected ULA to launch its first two Dream Chaser cargo missions in 2020 and 2021 atop Atlas V boosters.



Sierra Nevada Corp. Dream Chaser docks at the International Space Station. Image Credit: SNC

Original plans called for the use of the “552” version of the Atlas V—equipped with a 16-foot-diameter (5-meter) payload fairing, five strap-on solid-fueled rockets and a Dual-Engine Centaur (DEC) upper stage—but in August 2019 it was announced that Dream Chaser would instead fly atop the as-yet-unflown Vulcan-Centaur, which is targeted to make its maiden flight next year. Current plans call for the first Dream Chaser to ride Vulcan-Centaur’s second certification mission at some point in the fall of 2021.

Both wings for Tenacity arrived last month at the company’s Louisville, Colorado production facility, kicking off the much-anticipated integration phase of a beautiful and critical differentiator for Dream Chaser, the world’s only spaceplane owned by a private company and under contract with NASA.



SNC’s Dream Chaser® Spaceplane Wings Arrive in Colorado. Photo: SNC

“The wings are here and now we truly have butterflies in anticipation of this integration phase for Dream Chaser,” said SNC President Eren Ozmen. “Our spaceplane looks and functions unlike anything else in space – more technologically advanced but with all the heritage of the space shuttle program in its design. Dream Chaser’s first flight will be a soaring moment for all of us.”

Each wing is more than 13 feet long and the vehicle is 30 feet long. Unlike typical airplane wings, Dream Chaser wings aren’t fixed. During launch, the wings are stowed in the fairing & deploy on-orbit.

The arrival kicks off the integration of the complex Wing Deployment System (WDS) as part of the continued assembly and integration of the vehicle. With their innovative folding design, the wings are stowed in the fairing ahead of launch. After the launch vehicle separates, the WDS deploys the wings and locks them into place. Dream Chaser’s steeply angled wings function as stabilizers for the lift generated by the body of the vehicle.



SNC designed the primary structure & subcontractor Lockheed Martin helped build it. The vehicle is currently in assembly & integration, during which time SNC will be adding key structural, mechanical, electrical and thermal protection systems (and the wings). Photo: SNC

“The wings for Dream Chaser presented an interesting design challenge,” said Dream Chaser program director John Curry. “Not only must they survive in low-Earth orbit like a satellite, but they need to be operational in Earth’s atmosphere, like an aircraft.” Just like the structural body for Dream Chaser, the wings were manufactured by Lockheed Martin in Texas, a subcontractor to SNC, and are single bonded composite structures. This state-of-the-art technology saves weight without compromising strength and stiffness. 

“Dream Chaser is a story of grit and tenacity on the part of SNC’s team,” said John Curry, SNC program director for Dream Chaser. “NASA’s vision and ours for a next-gen space shuttle with a gentle runway landing has weathered tough economic and budget resources and competing visions. The team and engineers working on Dream Chaser have believed in its superior design, knowing tenacity would lead to Dream Chaser flying in space and returning humans and science back to Earth safely.”
 

Source: https://www.americaspace.com/2020/05/04/first-dream-chaser-gets-its-wings-and-a-new-name-tenacity/

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Odp: Artykuły o Dream Chaser
« Odpowiedź #2 dnia: Czerwiec 10, 2021, 03:33 »
Sierra Space signs Dream Chaser agreement with British spaceport
by Jeff Foust — June 9, 2021 [SN]


Dream Chaser landing at the end of a low-altitude glide flight at Edwards Air Force Base. Sierra Space said a new agreement will support potential future landings of the vehicle at Spaceport Cornwall in England. Credit: NASA

WASHINGTON — Sierra Space, the new space subsidiary of Sierra Nevada Corporation, announced June 9 that it signed an initial agreement with a British spaceport that could lead to landings of the company’s Dream Chaser vehicle there.

Sierra Space signed a memorandum of understanding (MOU) with Spaceport Cornwall expressing support for future landings of Dream Chaser at the spaceport, also known as Cornwall Newquay Airport in southwestern England.

Source: https://spacenews.com/sierra-space-signs-dream-chaser-agreement-with-british-spaceport/

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Odp: Artykuły o Dream Chaser
« Odpowiedź #2 dnia: Czerwiec 10, 2021, 03:33 »