July 21, 2017 by Chris Bergin

The long-awaited return of American astronauts launching on US spacecraft, a capability last seen when Atlantis closed out the Shuttle Program in 2011, is set to return next year. Along with new crew transporters, the Space Shuttles legacy will be honored by the return of a lifting body vehicle, as Dream Chaser makes progress towards her role for uncrewed ISS resupply efforts. Commercial Spacecraft:

Two spacecraft are in a race to launch Americans to the International Space Station (ISS), a capability that has been exclusively conducted by the Russians with a hefty price tag via their Soyuz spacecraft following the 2011 retirement of the Space Shuttle fleet.

The Space Shuttle programs storied 30+ year flight history came to an emotional conclusion six years ago today whenAtlantis dropped from thepre-dawn darkness into the lights illuminating runway 15 at the Kennedy Space Center.

When Atlantis wheels came to a stop just before 5:58am on 21 July 2011, the conclusion of the Shuttle programresulted in a planned crew launch capability gap for the U.S., though few at the time believed the gapwouldlast more than a few years.

Originally, a transition period using the Orion spacecraft in an opening role of launching crew to the ISShad been considered before the demise of the Constellation Program (CxP) created an uncertain future for Orion.

When the SLS program architecture was announced in September 2011, Orion was re-revealed as an exclusivelyBeyond Earth Orbit (BEO) vehicle.

Notably, this change of call sign for Orions future missions was part of a further transition towards handing over Low Earth Orbit (LEO) to the commercial sector, a partnership between NASA and the space launch industry that resulted in the agency contracting out its LEO obligations to commercial companies, all with NASA oversight.

The commercialization of LEO, focused on a supply line to the ISS, began by complementing existing resupply vehicles, such as Russias Progress, Japans HTV and ESAs ATV spacecraft. Joining the resupply team were Orbital ATKs Cygnus and SpaceXs Dragon cargo spacecraft.

Although both vehicles have suffered from a launch vehicle-related failure, the Commercial Resupply Services (CRS) program has proven its worth, paving the way for a second phase, known as CRS2, to continue to provide commercial supply runs into the 2020s.

CRS2 expands the number of flights on the manifest for Cygnus and cargo Dragon whilst also welcoming Dream Chaser to the uncrewed fleet.

A fan favorite in the space flight community, Dream Chaser was one of the main contenders to launch American astronauts to the Station during the Commercial Crew competitionphase.

That crew version of the spacecraft is still technically within NASAs thoughts, as she completes the CCiCAP (Commercial Crew Integrated Capability) element of a NASA contract that was part of the Agencys Commercial Crew Program (CCP) aspirations.

Despite variouslevels of international interest, the crewed version of Dream Chaser faces an uncertain future. However, her new version an uncrewed cargo variant has a lot to look forward to.

As recently noted by SNC, Dream Chaser is currently undergoing a second roundof testing at the Dryden Flight Research Center in California, mirroring the tests conducted in 2013 that resulted in a successful set of milestones, only to be ruined by one of her landing gear gear that was salvaged from a fighter jet failing to deploy during landingthe resulted in the vehicle crashing off the side of the runway.

The spacecraft, a repaired and modified Engineering Test Article (ETA), is currently moving through tow tests ahead of Captive Carry tests and on a date yet to be decided this fall a replay of her free flight and landing that will hopefully conclude the test program with a safe rollout on Edwards Air Force Base runway 22L.

SNC is building two cargo Dream Chasers, each able to fly a total of 30 times over a 10 year lifetime. They, as expected, will be launched by United Launch Alliances Atlas V rocket, with a contract that confirms the partnership signed just this week.

ULA is pleased to partner with Sierra Nevada Corporation to launch its Dream Chaser cargo system to the International Space Station in less than three years, said Gary Wentz, ULA vice president of Human and Commercial Systems, speaking about the deal for the first two launches. We recognize the importance of on time and reliable transportation of crew and cargo to Station and are honored the Atlas V was selected to continue to launch cargo resupply missions for NASA.

Dream Chasers partnership with Atlas V goes back as far as the SpaceDev days, which first provided a fascinating glimpse of the lifting body spacecraft perched on top of the Atlas Vs Centaur upper stage.

The latest version of Dream Chaser is more streamlined and fits inside the large Atlas V fairing. The first launch is expected to take place in 2020.

SNC recognizes the proven reliability of the Atlas V rocket and its availability and schedule performance makes it the right choice for the first two flights of the Dream Chaser, added Mark Sirangelo, corporate vice president of SNCs Space Systems business area.

ULA is an important player in the market and we appreciate their history and continued contributions to space flights and are pleased to support the aerospace community in Colorado and Alabama.

Along with Dream Chasers often-touted dissimilar redundancy by way of being a different type of spacecraft when compared to her capsule based colleagues she will add to NASAs downmass capability, a required element that only Dragon is currently capable of achieving for the CRS program.

This downmass capability which includes time-sensitive science payloads will be returned directly to land, with Dream Chaser utilizing her design by landing on a runway, allowing for quick access to critical experiments.

While Orbital ATKs Cygnus can only look forward to a destructive re-entry at the conclusion of her mission, SpaceXs Dragon returns to a Pacific Ocean splashdown before being shipped back to the Port of Los Angeles and then eventually to Texas for a full mission debrief.

Interestingly, land and sea returns will now be the forward pathfor NASAs two CCP partners, SpaceX and Boeing.

SpaceXs Dragon 2 is nowconfirmed to be returning only to a splashdown in the Pacific, after an anticipatedtransition to a propulsive land landing capability via her SuperDraco thrusters was deleted.

Elon Musk confirmed while noting the related impact on the now-cancelled Red Dragon that propulsive landings are too challenging for the interim, which means Dragon 2 will be heading for water landings via parachutes.

Notably, Dragon 2 was always going to use parachutes, albeit just on the opening crew missions, before transitioning to apropulsive landing.

Regardless of landing style, as previously reported, the first launch of SpaceXs newDragon 2 on an uncrewed demonstration mission to the ISS has now officially slipped into 2018, with the SpX Demo-1 mission now set for February of next year, followed by SpX Demo-2, this time with a crew, in June.

Dragon 2s rival, Boeings Starliner had no plans for propulsive landings, but will interestingly return to land to conclude her crew missions thanks to an invention called airbags, as one Boeing employee cheekily referenced when comparing his spacecraft to other returning vehicles.

Starliner will return under parachutes before inflating itsairbag system at the base of the capsule to allow for a soft touchdown at the landing site. This capability has already been tested during Starliners development program.

The spacecraft like Dream Chaser has partnered with ULA forAtlas V launches en route to the Station.

The first Starliner launch known as the Orbital Flight Test (OFT) is now set to take place in June ahead of a crewed version of themission (the Crewed Flight Test CFT) currently scheduled just two months later in August.

All four missions will be heavily reviewed after each flight prior to NASA working a certification process that will green light the spacecraft for official NASA crew rotation missions.

While Soyuz continues to be contracted for the interim, including an overlap during this initial period as a back-up in case of problems with the commercial vehicles, the ultimate aim is to focus NASA money on American vehicles, as opposed to paying for seats on Soyuz.

(Images: Boeing, SNC, SpaceX, NASA, andL2 artist Nathan Koga The full gallery of Nathans (Starliner to SpaceX Dragon to MCT, SLS, Commercial Crew and more) L2 images can be *found here*)

Read the rest here:

On Atlantis' anniversary, USA's future space fleet closing in on maiden flights - NASASpaceflight.com