Gwynne Shotwell just made some very interesting remarks on Friday.
https://spaceflightnow.com/2019/12/07/af...ew-dragon/
""We definitely learned a lot," Shotwell said Friday. "NASA warned us that crew is going to be 10 times harder than cargo. And I think that we were like, 10 times harder? What does that mean? What does that look like?"
In a discussion with reporters Friday at SpaceX's headquarters and factory in Hawthorne, California, Shotwell identified four main reasons for the Crew Dragon delays.
1. "We had an architecture that we wanted to fly and land propulsively," Shotwell said. "We thought it was the safest way to do it. Technically it was complex, and in addition, as NASA and SpaceX were going down this journey, it became clear to us it was going to be very difficult to certify that."
"So we pulled the plug on that technology. So we wasted time. We learned a lot, but we spent some time on that. In the end, if you pull that out, there are elements in the vehicle that you have to redesign."
2. The original Crew Dragon design had seats for seven astronauts. But NASA didn't like the angle of the seats.
"With this change and the angle of the seats, we could not get seven anymore," Shotwell said. "So now we only have four seats. That was kind of a big change for us."
3. The third thing is kind of obvious, the "anomaly"/explosion during the Crew Dragon static fire test. Sorting that out has added several months.
4. And lastly, the parachutes. Though they worked fine for the Demo1 mission that delivered Ripley and Little Earth to the Space Station, they experienced some problems during a supply flight in 2018.
"The fourth thing that's caused delays is the parachutes," Shotwell said.
"NASA had, since the Apollo program, a way of determining the loads in the risers on the parachutes," Shotwell said. "They made a conservative assumption ... from the Apollo program. We did it. Boeing did it. We were just following their standard."
But since the parachute problem noted with a supply Dragon in 2018, they put instruments on the risers to measure the actual loads.
"This riser is getting way more load than any of our models have ever predicted," she said. "So NASA's like, 'OK, this is good learning. So our way of analyzing margin has not been as robust as we thought.' You basically have to make the risers more robust, which makes the parachutes heavier and larger," she continued. "But the capsule is designed. I can't make the capsule bigger... Then we had to go to thinner canopy material, so it's been kind of trial and error."
"We're the ones that found this issue," Shotwell said. "I think we know parachutes better than anybody on the planet right now ... So we worked on the risers, we worked on the stitching, we worked on the canopy material."
"We have to close out the parachutes", she said. "We've flown seven cluster tests. We said we were going to fly 10, so we've got at least three to go. My guess is we're going to do more."
"We've got the in-flight abort to fly", she said. "We'll get data, analyze data, and make sure we're good ... We're on the range for that on Jan.4."
Bottom line, they seem to hope that they can get the manned DM-2 off by the end of February. But no guarantees.
Here's Gwynne:
https://spaceflightnow.com/2019/12/07/af...ew-dragon/
""We definitely learned a lot," Shotwell said Friday. "NASA warned us that crew is going to be 10 times harder than cargo. And I think that we were like, 10 times harder? What does that mean? What does that look like?"
In a discussion with reporters Friday at SpaceX's headquarters and factory in Hawthorne, California, Shotwell identified four main reasons for the Crew Dragon delays.
1. "We had an architecture that we wanted to fly and land propulsively," Shotwell said. "We thought it was the safest way to do it. Technically it was complex, and in addition, as NASA and SpaceX were going down this journey, it became clear to us it was going to be very difficult to certify that."
"So we pulled the plug on that technology. So we wasted time. We learned a lot, but we spent some time on that. In the end, if you pull that out, there are elements in the vehicle that you have to redesign."
2. The original Crew Dragon design had seats for seven astronauts. But NASA didn't like the angle of the seats.
"With this change and the angle of the seats, we could not get seven anymore," Shotwell said. "So now we only have four seats. That was kind of a big change for us."
3. The third thing is kind of obvious, the "anomaly"/explosion during the Crew Dragon static fire test. Sorting that out has added several months.
4. And lastly, the parachutes. Though they worked fine for the Demo1 mission that delivered Ripley and Little Earth to the Space Station, they experienced some problems during a supply flight in 2018.
"The fourth thing that's caused delays is the parachutes," Shotwell said.
"NASA had, since the Apollo program, a way of determining the loads in the risers on the parachutes," Shotwell said. "They made a conservative assumption ... from the Apollo program. We did it. Boeing did it. We were just following their standard."
But since the parachute problem noted with a supply Dragon in 2018, they put instruments on the risers to measure the actual loads.
"This riser is getting way more load than any of our models have ever predicted," she said. "So NASA's like, 'OK, this is good learning. So our way of analyzing margin has not been as robust as we thought.' You basically have to make the risers more robust, which makes the parachutes heavier and larger," she continued. "But the capsule is designed. I can't make the capsule bigger... Then we had to go to thinner canopy material, so it's been kind of trial and error."
"We're the ones that found this issue," Shotwell said. "I think we know parachutes better than anybody on the planet right now ... So we worked on the risers, we worked on the stitching, we worked on the canopy material."
"We have to close out the parachutes", she said. "We've flown seven cluster tests. We said we were going to fly 10, so we've got at least three to go. My guess is we're going to do more."
"We've got the in-flight abort to fly", she said. "We'll get data, analyze data, and make sure we're good ... We're on the range for that on Jan.4."
Bottom line, they seem to hope that they can get the manned DM-2 off by the end of February. But no guarantees.
Here's Gwynne: