SpaceX Falcon 9 / Dragon 2 : SpX-DM1 : March 2, 2019 : DISCUSSION

[Joffan]

Also do we know why they are opening the nose cone so early? Would not keeping it closed be an extra protection from MMOD possible damage to the dock? Are they opening it early to check they can open it?

This very plausible answer is that the star tracker is under the nose cone; so the cap needs to be open for Dragon to navigate:

I believe the star trackers are under the nose cap, so the nose cap will likely open quickly after launch and stay open until shortly before re-entry.

[JBF]

Also do we know why they are opening the nose cone so early? Would not keeping it closed be an extra protection from MMOD possible damage to the dock? Are they opening it early to check they can open it?

This very plausible answer is that the star tracker is under the nose cone; so the cap needs to be open for Dragon to navigate:

I believe the star trackers are under the nose cap, so the nose cap will likely open quickly after launch and stay open until shortly before re-entry.

Additionally if they have to jettison the cap it is better to do it safely out of the way

[Phillip Clark]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

To date the US cargo freighters to ISS have been incapable of completing a fully-automatic docking: they are always parked close to ISS and then brought in to berthing using a remote manipulator.

Compare with the Soviet Union/Russia.   They completed the first docking between unmanned spacecraft in 1967 when Cosmos 186 and Cosmos 188 (unmanned Soyuz spacecraft) completed an unmanned docking.   The first unmanned docking with a space station was in 1975 when the unmanned Soyuz 20 docked with Salyut 4.   And then in 1978 the Soviets started to launch unmanned Progress cargo freighters to orbital stations (Salyut 6 initially) on a regular basis.

Even the Chinese have beaten the US with the ability to perform automatic dockings when the unmanned Shenzhou 8 docked with Tiangong 1 in 2011.

So, let us see how the first US attempt to complete a fully-automatic docking works out with the DM 1 mission.

[Scylla]

Excellent 40.9 megapixel panorama of DM-1 on reddit. Shows crew access arm has been attached to Dragon.
https://www.reddit.com/r/spacex/comments/aw6g7j/rspacex_cctcap_demo_mission_1_media_thread_videos/

[Lar]

A little less arguing with the mods please.

"my comments weren't aspersions, they were facts" would be a) false and b) arguing. Don't

[Lar]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

(fan) Why do you think that this flight isn't generating much interest? I might be missing out on who is and isn't interested but I see high interest. Could be wrong.

[envy887]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

(fan) Why do you think that this flight isn't generating much interest? I might be missing out on who is and isn't interested but I see high interest. Could be wrong.

DM-1 is getting plenty of interest. The fact that it is the first US autodocking vehicle is not.

[abaddon]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

(fan) Why do you think that this flight isn't generating much interest? I might be missing out on who is and isn't interested but I see high interest. Could be wrong.

DM-1 is getting plenty of interest. The fact that it is the first US autodocking vehicle is not.

Isn't it also the first automated docking of any vehicle to the ISS not using Russian technology?  IIRC HTV berths and ATV used the Russian system.

[edkyle99]

]So, as linked in the update thread, we have our answer: Crew Dragon and cargo mass 26577 pounds (isn't that a very precise number) or 12055 kilograms / 12 metric tons.  The cargo is 449.7 pounds (but does this include Ripley?  Probably not).  So we're looking at ~11.75 fueled for DM-1 Crew Dragon, sans cargo.

Per Stephen Clark's updates, that is the docking mass, not the launch mass. Dragon 2 doesn't shed any fairings between launch and docking, so except for some expended Draco RCS fuel I'm not sure what the difference would be.

I'm going to guess 500 kg of propellant from insertion to reach ISS.  I'm way off, I'm sure.

 - Ed Kyle

[Rocket Science]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

(fan) Why do you think that this flight isn't generating much interest? I might be missing out on who is and isn't interested but I see high interest. Could be wrong.

Might have something to do with not having a crew on board, the whole risk of life drama... Just my opinion...

[envy887]

]So, as linked in the update thread, we have our answer: Crew Dragon and cargo mass 26577 pounds (isn't that a very precise number) or 12055 kilograms / 12 metric tons.  The cargo is 449.7 pounds (but does this include Ripley?  Probably not).  So we're looking at ~11.75 fueled for DM-1 Crew Dragon, sans cargo.

Per Stephen Clark's updates, that is the docking mass, not the launch mass. Dragon 2 doesn't shed any fairings between launch and docking, so except for some expended Draco RCS fuel I'm not sure what the difference would be.

I'm going to guess 500 kg of propellant from insertion to reach ISS.  I'm way off, I'm sure.

 - Ed Kyle

Probably not that far off. If the final mass at 410 km circular orbit is 12055 kg, and Draco specific impulse is 310 s, and Falcon drops Dragon off in a 250 km circular orbit and it does a 2-burn orbit raise, I get a initial mass in orbit of 12426 kg. So about 370 kg of fuel burn.

[CuddlyRocket]

Isn't it also the first automated docking of any vehicle to the ISS not using Russian technology?

You may have the reason for the lack of interest in the docking there! Is it the first docking of any vehicle? No. The first automated docking? No. The first automated docking to the ISS? Still no. How about the first automated docking of any vehicle to the ISS not using Russian technology? YES!!! Hang out the bunting.

[Steven Pietrobon]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

How much interest did Korabl-1, Mercury-BJ 1, Kosmos 47, Gemini 1, Kosmos 133, Apollo 201 and Shenzhou 1 (for Vostok, Mercury, Voskhod, Gemini, Soyuz, Apollo and Shenzhou) generate compared to their first crewed flights? Wait until the first crewed launch. That is going to be crazy!

[Prettz]

The fact that this launch is in the middle of the night doesn't help. Not going to be any iconic visuals from it, either, on account of that. The images of it approaching the station will be great, at least.

[Paul_G]

Would assume they want to confirm it works before starting the trip to the ISS. This is a new nose cone so never been tried before.

Is there an equivalent of the  Cargo Dragkn star tracker under the nose cone? I seem to remember that the opening of the panel that reveals the grapple point on Cargo Dragon also exposes the star tracker for navigation?

Paul

[ejb749]

...now we know where Elon's watching the launch from

He'll probably move away from there before the launch.   

[MechE31]

Would assume they want to confirm it works before starting the trip to the ISS. This is a new nose cone so never been tried before.

Is there an equivalent of the  Cargo Dragkn star tracker under the nose cone? I seem to remember that the opening of the panel that reveals the grapple point on Cargo Dragon also exposes the star tracker for navigation?

Paul

Cargo dragon has the star tracker in the GNC bay.

[Khadgars]

So excited for this launch! 

[Phillip Clark]

Something about this flight is not generating much interest.   This will be the first attempt by an unmanned US spacecraft to be launched and then complete a full automatic docking with an already-orbiting spacecraft (ISS in this case).

(fan) Why do you think that this flight isn't generating much interest? I might be missing out on who is and isn't interested but I see high interest. Could be wrong.

I was meaning that an aspect of this flight is not generating any interest, not that the flight itself isn't generating interest.

[docmordrid]

From online comments I've read, flying at 0249;03 Eastern has a bit to do with it.