Author Topic: SpaceX F9 / Dragon 2 : CRS2 SpX-21 - Mission Updates : Dec - Jan (2020/21) (Read 192560 times)

gongora · « **on:** 08/21/2020 03:08 am »

CRS-21 Discussion thread.

NSF Threads for CRS-21 : Discussion

NSF Articles for SpaceX CRS : https://www.nasaspaceflight.com/?s=CRS%2BSpaceX
NSF Articles for CRS missions : https://www.nasaspaceflight.com/?s=CRS

Successful launch December 6, 2020 at 11:17am EST (16:17 UTC) on Falcon 9 (booster 1058.4) from LC-39A at Kennedy Space Center. ASDS booster landing on OCISLY (towed by Hawk) was successful. First flight of the cargo variant of Dragon 2. First SpaceX flight under the CRS-2 contract.

External cargo: Nanoracks Bishop Airlock (Nanoracks Discussion Thread / Bishop on Nanoracks site)

Other SpaceX resources on NASASpaceflight:
SpaceX News Articles (Recent) / SpaceX News Articles from 2006 (Including numerous exclusive Elon interviews)
SpaceX Dragon Articles / SpaceX Missions Section (with Launch Manifest and info on past and future missions)
L2 SpaceX Section

gongora · « **Reply #1 on:** 08/21/2020 03:13 am »

With the new date for Crew 1 I would guess this slips a little, but there hasn't been any announcement of a change. The countdown on the Nanoracks site hasn't changed. There are a lot of details that I don't know for this mission. How does the mass of cargo Dragon 2 compare to cargo Dragon? Will it still RTLS?

vt_hokie · « **Reply #2 on:** 08/29/2020 09:15 pm »

Are there any images of the new cargo Dragon yet?

Bob Shaw · « **Reply #3 on:** 08/29/2020 10:10 pm »

I had the impression that both current Dragon variants are externally identical, and that the only real differences are internal to the cabin. Those differences being the removal of crew-centric features like seats, food, toilet etc and their replacement with standardised cargo bags.

Jimmy_C · « **Reply #4 on:** 08/29/2020 10:44 pm »

Quote from: Bob Shaw on 08/29/2020 10:10 pm

I had the impression that both current Dragon variants are externally identical, and that the only real differences are internal to the cabin. Those differences being the removal of crew-centric features like seats, food, toilet etc and their replacement with standardised cargo bags.

I thought Cargo Dragon 2 used CBM and thus needs a grapple fixture for Canadarm. Crew Dragon 2 docks with the NDS, obviously. Using CBM has several advantages for cargo: Berthing frees a docking port for a second crew vehicle, should one be needed. CBM also has a larger portal for cargo transfer.

Can someone answer whether the CBM port forms a structurally stronger latch than NDS? Also does a CBM connection form a stronger seal as well than a NDS connection?

gongora · « **Reply #5 on:** 08/29/2020 10:55 pm »

All new Dragons will dock. Cargo Dragon-2 doesn't have the Super Draco engines.

the_other_Doug · « **Reply #6 on:** 08/30/2020 02:58 pm »

As I recall, one of the options for CRS-2 was that Cargo Dragon 2 would be able to fly with either an IDS docking system installed, or a CBM berthing system like the earlier cargo craft. And that this was sort of refined later to a "hey, tell us when and if you want a Dragon 2 rebuilt with a CBM for berthing, and we'll do it, otherwise for most flights we'll just dock normally."

Since at least one other cargo option berths using the CBM hardware, I sort of get the feeling we won't ever see a berthing version of the Dragon 2 during the upcoming CRS2 flights. Things too big to come through the IDS hatches will go up on the HTV-X, as of now. And hey, when it's a pain in the butt to have to fly a special config to get a whole new rack up there, planners will start breaking down the rack contents so they can fit through the available docking hatches and get it up there more easily...

gongora · « **Reply #7 on:** 08/30/2020 03:06 pm »

Cygus will continue berthing, Dream Chaser will also berth. Right now Dragon is the only cargo vehicle that will be docking on the USOS side.

the_other_Doug · « **Reply #8 on:** 08/30/2020 03:21 pm »

That's the nice thing about having different logistics configurations at your disposal. Smaller things can be bagged and passed through the smallest hatches, in the Russian segment. Next largest things can go in a Dragon or a Starliner, through the somewhat larger IDS hatches, and finally Cygnus, HTV-X and Dream Chaser can berth with the largest available hatches. And, of course, Dragon can still carry unpressurized equipment in the trunk, like always.

It's far easier to support ISS when you can plan your various logistics and resupply needs, both upmass and downmass, pressurized and not, through a rich variety of vehicles. Much better than being stuck with just one or two.

Alexphysics · « **Reply #9 on:** 08/30/2020 05:36 pm »

Too many people repeat the thing about large items but there aren't really that many large items that need to be transfered either in or out of the station.

king1999 · « **Reply #10 on:** 08/31/2020 04:21 am »

Quote from: gongora on 08/30/2020 03:06 pm

Cygus will continue berthing, Dream Chaser will also berth. Right now Dragon is the only cargo vehicle that will be docking on the USOS side.

You know, that's probably why they can charge a little more than Dragon 1. Look, no hands

Sesquipedalian · « **Reply #11 on:** 08/31/2020 04:52 am »

Quote from: Alexphysics on 08/30/2020 05:36 pm

Too many people repeat the thing about large items but there aren't really that many large items that need to be transfered either in or out of the station.

As I recall, the only thing that was an issue was a packed spacesuit. And even then, they decided that they would just pack the spacesuit inside the Dragon itself.*

* The suit could fit through the hatch, and so could the disassembled packing assembly/enclosure, but the entire packed suit+assembly could not fit.

scr00chy · « **Reply #12 on:** 09/03/2020 12:22 am »

SFN schedule is showing this launch slipped to November.

SMS · « **Reply #13 on:** 09/03/2020 11:09 am »

http://www.collectspace.com/ubb/Forum18/HTML/001608.html

Quote

AB Emblem's embroidered version of NASA's patch for the SpaceX CRS-21 resupply mission to the International Space Station. The flight marks the first use of Dragon 2 in its cargo configuration.

gongora · « **Reply #14 on:** 09/06/2020 03:58 pm »

This is now shown as November 15 on the latest SMSR schedule.

oldAtlas_Eguy · « **Reply #15 on:** 09/07/2020 06:42 pm »

Quote from: gongora on 09/06/2020 03:58 pm

This is now shown as November 15 on the latest SMSR schedule.

Expected due to the movement of a crew docking moving to late October. The crew mission has to dock and then after the crew is "settled" then a Cargo can be done. VV events close together is usually avoided.

Lars-J · « **Reply #16 on:** 09/07/2020 08:35 pm »

Is this flight going to dock at IDA-1 or 3?

gongora · « **Reply #17 on:** 09/07/2020 08:55 pm »

Is it 1 & 3 or 2 & 3 for the IDA locations?

The Cargo Dragons should be on Node 2 Zenith/IDA-3. Crew Dragons can use either docking port.

Comga · « **Reply #18 on:** 09/07/2020 09:09 pm »

Quote from: gongora on 09/07/2020 08:55 pm

Is it 1 & 3 or 2 & 3 for the IDA locations?

The Cargo Dragons should be on Node 2 Zenith/IDA-3. Crew Dragons can use either docking port.

According to Gunter's IDA-1 was lost on CRS-7,
IDA-2 is on Node-2 Forward, and
IDA-3 is on Node-2 Zenith

edit: IDA not PMA! Thanks Sesq!

Sesquipedalian · « **Reply #19 on:** 09/07/2020 09:18 pm »

IDA-2 is on PMA-2, and IDA-3 is on PMA-3. The numbers are nicely consistent.

In one sense I'm glad this happened, otherwise we'd be talking about IDA-2 on PMA-3 and confusing ourselves on a regular basis.

Quote from: Comga on 09/07/2020 09:09 pm

According to Gunter's PMA-1 was lost on CRS-7,
PMA-2 is on Node-2 Forward, and
PMA-3 is on Node-2 Zenith

On the other hand that doesn't prevent us from confusing ourselves in other ways. You linked to Gunter's page on the IDAs but your post mentions the PMAs. It was IDA-1 that was lost, not PMA-1. PMA-1 links the US segment with the Russian segment.