NASA explains why it picked Boeing over Sierra Nevada
In a report released by NASA late last week, the agency outlined the reasons it picked Boeing’s CST-100 manned capsule over Sierra Nevada’s Dream Chaser mini-shuttle for the second contract to provide manned ferry capabilities to ISS.
Sierra Nevada’s Dream Chaser spacecraft, which would take off on top of a United Launch Alliance Atlas 5 rocket and land on a runway like the space shuttle, is not as far along in development as the competing CST-100 and Crew Dragon capsules proposed by Boeing and SpaceX, according to a source selection statement signed by Bill Gerstenmaier, head of NASA’s human exploration and operations directorate. “A winged spacecraft is a more complex design and thus entails more developmental and certification challenges, and therefore may have more technical and schedule risk than expected,” Gerstenmaier wrote in the selection statement.
NASA wants to have the commercial crew capsules operational by the end of 2017 to end U.S. purchases of astronaut seats on Russia’s Soyuz ferry craft. Before NASA permits its astronauts to fly on the CST-100 and Crew Dragon, each spaceship will go through ground testing and complete unpiloted and crewed test flights.
The reasoning seems quite reasonable. It also suggests that Sierra Nevada might have a better shot at winning a contract during the next round for cargo, as scheduling will not be as critical since NASA has other alternatives to get cargo to ISS.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
In a report released by NASA late last week, the agency outlined the reasons it picked Boeing’s CST-100 manned capsule over Sierra Nevada’s Dream Chaser mini-shuttle for the second contract to provide manned ferry capabilities to ISS.
Sierra Nevada’s Dream Chaser spacecraft, which would take off on top of a United Launch Alliance Atlas 5 rocket and land on a runway like the space shuttle, is not as far along in development as the competing CST-100 and Crew Dragon capsules proposed by Boeing and SpaceX, according to a source selection statement signed by Bill Gerstenmaier, head of NASA’s human exploration and operations directorate. “A winged spacecraft is a more complex design and thus entails more developmental and certification challenges, and therefore may have more technical and schedule risk than expected,” Gerstenmaier wrote in the selection statement.
NASA wants to have the commercial crew capsules operational by the end of 2017 to end U.S. purchases of astronaut seats on Russia’s Soyuz ferry craft. Before NASA permits its astronauts to fly on the CST-100 and Crew Dragon, each spaceship will go through ground testing and complete unpiloted and crewed test flights.
The reasoning seems quite reasonable. It also suggests that Sierra Nevada might have a better shot at winning a contract during the next round for cargo, as scheduling will not be as critical since NASA has other alternatives to get cargo to ISS.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
This is the important line:
“’A winged spacecraft is a more complex design and thus entails more developmental and certification challenges, and therefore may have more technical and schedule risk than expected,’ Gerstenmaier wrote in the selection statement.”
The old KISS rule still applies (“Keep it simple, silly!”).
PS: Thanks, Bob, for this site and all the work you do!