25 thoughts on “Crew Dragon”

1. Re: Soyuz, I suggest not burning that bridge although the less we depend on it the better.

   1. Yeah, don’t want to burn the bridge. We want the Russians to feel good about buying rides from American companies in a few years.

2. Speaking as a layman it seems weird that it takes two years to build one capsule.

   1. Gotta check all the boxes NASA wants checked.

      1. I figured that had to be part of it.

3. Could SpaceX have flown its own astronauts before all of the NASA boxes were checked?

   1. Yeah. But they’re using NASA launch facilities. So the boxes must be checked. Also, FAA.

4. Rand: And NASA is now saying that the first crewed flight, scheduled for spring of next year, may be operational. And no more Soyuz flights after that. Should have happened long ago, though.

   Are basing that on Michael Baylor’s tweet: Gerst: There is potentially a contract change for SpaceX to make DM-2 an operational crew rotation mission.

   Without more context, I interpret that not as a suggestion that they will end the Soyuz rides early, but that if DM2 is delayed well past spring 2019 and into the fall or winter, they will have a contingency plan to convert it into an operational mission. That was the rational give for the Boeing contract negotiation. Have you heard something else?

5. I wonder what would happen if SpaceX announced; “Hey, we haven’t actually built the life support system yet, so we”re gonna go ahead and fly DM-1 without it. And, we’re going to skip installing the displays and crew controls and stuff, too. The first flight of the life support system and crew controls will be on DM-2, with crew. Oh, and did we forget to mention we’re sending DM-2 around the moon, so a quick return in case of trouble is not an option.”

   What would NASA say about all that? Probably plenty, in spite of the fact what I said above is actually true for EM1 and EM-2. (yes, they really are skipping life support and crew displays and controls for the unmanned SLS/Orion EM-1, and all that gear will see space for the first time on a manned lunar mission, EM-2).

   Remember, NASA rules apply to everyone, except for NASA.

6. I thought there was some rule about the stack has to fly seven times before putting crew on top?

   1. There is such a NASA rule, though it may be 5 times (I’m not sure). That applies to commercial launchers.

      However, it does not apply to NASA. For example, SLS will first launch with the Interim Upper Stage. The larger (and all new and untested) Expedition Upper Stage will make its first flight on either EM2 or EM3 – so in other words, with a crew on top.

      1. NASA never has followed a rule like that. They only did two unmanned Saturn V flights before Apollo 8. The first Shuttle flight (STS-1) was manned.

      2. There is actually no such “7 flights” NASA rule. The NASA rule is simply that the providers prove that the vehicle is safe. Boeing came up a with a plan to prove that involving lots of design reviews, analysis, and ground testing. SpaceX came up with a different plan that involves a lot less up front paperwork and review, but more test flights. Back and forth with NASA on what qualifies as enough testing came up with the 7 flight number. NASA for SLS is following a documentation heavy plan much like Boeing is using for Starliner. That’s the traditional route for big aerospace, and NASA and the big aerospace companies are comfortable with it. SpaceX is going the agile route of testing by flying. For SpaceX, with cheap launchers and a high flight rate, they’d rather just fly. Obviously for SLS at a one every other year cadence for several billion dollars, that’s not the way to go.

7. Glad to see the Dragon has a toilet. Wonder what design they went with.

   Also, I wonder which way the hatches open on Dragon and Boeing’s capsules, given the lessons of historical spaceflight.

   1. Dragon hatch opens out and up. CST-100 hatch opens out and right.

   2. The Dragon 2 top hatch opens inward, as can be seen by the hinge in this photo.

      The labels are:

      To Open
      1. Deploy handle
      2. Turn crank [CCW] until it ratchets
      3. Stow handle
      4. Pull hatch open

      To Close
      1. Push hatch closed
      2. Deploy handle
      3. Turn crank [CW] until it ratchets
      4. Stow handle

      1. The Dragon side hatch opens out and up (as Leland says), as shown in this photo of the high fidelity capsule simulator.

      2. A hatch that opens inward seems a bit more inherently foolproof against opening to a hard vacuum. But for the side hatch there might be considerations during reentry.

         1. I took David’s mention of “the lessons of historical spaceflight” as a reference to the Apollo 1 where the inward opening, plug door hatch couldn’t be opened due to capsule overpressure.

         2. An inward opening hatch is light and strong. The cabin pressure is directed to the spacecraft structure, making for a tight seal. The Apollo Block I capsule had an inward opening hatch. When the fire erupted during the Apollo One plugs out test, the pressure made the door impossible to open quickly, which prevented the crew from escaping or being rescued by the pad crew.

            SpaceX’s Dragon II capsule has two hatches. The docking hatch opens inwards, which is perfectly reasonable. The cabin hatch opens outward for easier crew access and to improve their escape chances should something go terribly wrong.

8. What ever happened to the SpaceX lunar flyby? It seems to have mysteriously disappeared.

   1. The day before Falcon Heavy’s maiden flight, Mr. Musk announced that they would wait for the BFR to do the lunar flyby.

      From the pre-launch press conference:

      Musk: What we decided internally is to focus our future efforts on BFR. Now we’ll see how the BFR development goes. If that ends up taking longer than expected, then we’ll return to the idea of sending a Crew Dragon on Falcon Heavy around the Moon. And potentially doing other things with crew on Falcon Heavy. But right now it looks like BFR development is moving quickly and it will not be necessary to qualify Falcon Heavy for crewed spaceflight.

9. “And no more Soyuz flights after that.”

   If I am not mistaken, isn’t the current plan that, once the crew vehicles are in operation, one US astronaut will continue flying up on every Soyuz, and one Russian cosmonaut on every US commercial flight?

   1. Yes. To ensure there is always Russian and American presence on the ISS at all times even if a visiting vehicle stood down for any reason.

      1. That was what I thought. So on a typical American Commercial Crew flight, you would presumably have two U.S. astronauts (one of which would be the pilot), one Russian, and one European or Japanese astronaut. And a stack of supplies.

         Of course, this arrangement won’t go into place until the Dragon and Starliner reach operational status (i.e., it won’t happen on the first crewed test missions in 2019).

         It’s also possible that this arrangement could be revisited, especially if tensions increase between the ISS partners.

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