Author Topic: SpaceX Dragon XL  (Read 223175 times)

Offline StevenV

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Re: SpaceX Dragon XL
« Reply #60 on: 03/27/2020 10:46 pm »
Those thruster pods would also need covers.  Using the fairing seems much simpler, if it fits.

Offline illectro

Re: SpaceX Dragon XL
« Reply #61 on: 03/27/2020 10:52 pm »
Yep, using this with a regular fairing makes more sense since they're still doing fairing recovery, Cargo and crew dragon need to be conical for reentry stability, so they work well as their own fairings. In this case it'll probably work fine in a regular fairing, and that means one less thing to be developed.

If it looked like launch mass was an issue I could see them going with a custom fairing, but I think they'll be well within the capabilities of Falcon Heavy without worrying about that.

Offline Robotbeat

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Re: SpaceX Dragon XL
« Reply #62 on: 03/27/2020 10:58 pm »
1) probably would launch with an at least side booster reusable Falcon Heavy.
2) to LEO, could probably do reusable Falcon 9 just fine.
3) I bet it’ll be similar to their lunar lander bid for NASA.
4) both for this logistics module and for a lander, being the only domestic company that has already proven Autonomous rendezvous and docking with a space station gives them a huge leg up as this is considered a major risk item (exaggerated risk, IMHO, but NASA will be NASA).

5) It sounds weird, but yeah, you could launch this with Starship when Starship is ready. And possibly recover it as well. This gives SpaceX an early customer for deep space Starship usage with relatively low risk cargo (on the way back, at least) and an on-ramp to NASA becoming comfortable with Starship for greater and greater missions.
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Offline meekGee

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Re: SpaceX Dragon XL
« Reply #63 on: 03/27/2020 11:41 pm »
This is the first big new thing (e.g. not something like fairing recovery) from SpaceX we've heard in a while, at least since the Starship announcement, that I can think of.  Exciting!

For those who continue to claim F9 & Dragon are "dead ends" and SpaceX is trying to get rid of them in favor of Starship - this is a pretty compelling counter argument.  (Yes, long term.  Not so much short term).

I've often wondered what a SpaceX version of Cygnus would look like.  Now we know!
They will keep F9s as long as NASA doesn't realize it's in the wrong century.

Sadly, this may continue till well after SS launches.
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Offline GWH

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Re: SpaceX Dragon XL
« Reply #64 on: 03/28/2020 12:08 am »
5) It sounds weird, but yeah, you could launch this with Starship when Starship is ready. And possibly recover it as well. This gives SpaceX an early customer for deep space Starship usage with relatively low risk cargo (on the way back, at least) and an on-ramp to NASA becoming comfortable with Starship for greater and greater missions.

This is such a good way to look at it that people often miss. Lay the ground work for a future role of Starship by getting a foot in the door first with the "safe and proven" way of doing things.

Offline GWH

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Re: SpaceX Dragon XL
« Reply #65 on: 03/28/2020 12:26 am »
Spaceflight Now has a scoop with a lot more info than everyone else:
https://spaceflightnow.com/2020/03/27/nasa-picks-spacex-to-deliver-cargo-to-gateway-station-in-lunar-orbit/

Also despite some posters being adamant that this will fly without a fairing based on their own rampant speculation, this article puts that presumption to rest:
Quote
  SpaceX is building off the company’s Dragon 2 spacecraft designed to ferry crew and cargo to the International Space Station. Unlike the Dragon 2, which flies without an aerodynamic shroud on top of SpaceX’s Falcon 9 rocket, the Dragon XL will lift off inside a payload fairing on the company’s bigger Falcon Heavy launcher, according to Dan Hartman, NASA’s Gateway program manager at the Johnson Space Center in Houston.

It gon be in a fairing!

Online matthewkantar

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Re: SpaceX Dragon XL
« Reply #66 on: 03/28/2020 12:38 am »
The fairing makes sense if they are recovered. No need to have solar panel covers, nose cone, aero hardening, no bit thrown away.

Online CorvusCorax

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Re: SpaceX Dragon XL
« Reply #67 on: 03/28/2020 12:41 am »
Why would SpaceX make an expendable spacecraft?

1. NASA wants a cargo spacecraft to Lunar gateway.
2. NASA is paying real well for it.
3. NASA doesn't need return cargo.
4. But it needs long on orbit capability and pressurized internal storage.
5. It will have a really low flight rate/count

SpaceX has its main focus on other things (Star-*) , but if money can be made with minimal effort, why not?.
Because of 5 (low flight count/rate) any extensive reuseability and engineering effort isn't worth it anyway. Instead SpaceX would throw together the most effortless spacecraft they can possibly make:

1. Pressure vessel made from an old Falcon9 tank barrel. The factory and production capacity is already there.
2. Propulsion, Power, Life Support and Avionics system from Dragon2
3. Bigger batteries and more robust design for long orbital life.

Basically only "3" - needed for the long mission times - needs to be developed. But that's something SpaceX needs to look into for Mars trips anyway, so there's enough synergy to justify the development effort.

What does that get to?

I don't think this spacecraft will "wow" anyone at first glance. It will be a minimum viable solution thrown together with minimum effort possible (while still meeting NASA's quality requirements) I wouldn't be surprised if SpaceX could get this thing flight ready 3 or more years before the Gateway is even launched.

I also wouldn't be surprised if SpaceX would launch a test vehicle before the first operational mission and leave it in orbit for a several month long duration test. Aftewards, they can't land it, but why would you want to land it?

It has power, it has a docking port, it has life support, it has lots of internal volume to do science... This thing is actually a small space station in its own right. SpaceX could have its own private space station and have NASA pay for it as part for the Gateway supply contract.

And once Starship flies, you can scoop it up and bring it back with Starship ;)


Offline Zed_Noir

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Re: SpaceX Dragon XL
« Reply #68 on: 03/28/2020 12:50 am »
The first thing that occur to me is that SX borrowed the layout from the new JAXA HTV-X for the DXL.


reverse angle image of the HTV-X from JAXA on wikipedia

....
It gon be in a fairing!

It will be easier to just use the standard SX payload fairing than figure out how to jettison a newly developed nose cone.

Offline GWH

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Re: SpaceX Dragon XL
« Reply #69 on: 03/28/2020 01:04 am »
I think there are other benefits to no fairing too, the upside down configuration means that the unpressurized trunk no longer needs to carry launch loads. More flexible cargo options in the trunk are now available lengths and width wise, like that Canada Arm referenced in the Spaceflight now article.

All the little greebly bits like thrusters, antennas and radiators can be stuck on the outside without aerodynamic concerns. Total mass and ease of design should both be improved.

Offline docmordrid

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Re: SpaceX Dragon XL
« Reply #70 on: 03/28/2020 01:11 am »
Why would SpaceX make an expendable spacecraft?

SFN says cargo return could be added later.

Quote
And once Starship flies, you can scoop it up and bring it back with Starship ;)

That's one way. Another would be a mini-reentry vehicle stowed inside DXL. Krypton SEP for the return?
« Last Edit: 03/28/2020 01:11 am by docmordrid »
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Offline Tomness

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Re: SpaceX Dragon XL
« Reply #71 on: 03/28/2020 01:35 am »
Anybody getting the vibe this is a love child of F9/ 2nd stage & Dragon 1 & 2? Does the whole spacecraft need to be in the fairing? Could it be half in & half out? If so could they stow a full unpressurized Express Rack?

Offline M.E.T.

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Re: SpaceX Dragon XL
« Reply #72 on: 03/28/2020 01:36 am »
This is the first big new thing (e.g. not something like fairing recovery) from SpaceX we've heard in a while, at least since the Starship announcement, that I can think of.  Exciting!

For those who continue to claim F9 & Dragon are "dead ends" and SpaceX is trying to get rid of them in favor of Starship - this is a pretty compelling counter argument.  (Yes, long term.  Not so much short term).

I've often wondered what a SpaceX version of Cygnus would look like.  Now we know!

To the contrary, the minimalist “cheap as chips” approach shows this to be a practical stopgap to win NASA contracts with minimum rework to legacy systems, while Starship wraps up development.

This is a launch and throw it away system, contrary to SpaceX’s long term design philosophy. Basically, they’re happy to build it if NASA will pay for it.

But this remains a dead end once Starship becomes operational.

Offline edkyle99

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Re: SpaceX Dragon XL
« Reply #73 on: 03/28/2020 01:37 am »
I'm guessing these have to be fully expendable Falcon Heavy launches, to get 5 tonnes of cargo to lunar orbit in a spacecraft that has to weigh 5-times-something tonnes - maybe 20 tonnes at TLI with about 1/4th of that mass needed for lunar orbit insertion.

 - Ed Kyle
« Last Edit: 03/28/2020 02:15 am by edkyle99 »

Offline aero

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Re: SpaceX Dragon XL
« Reply #74 on: 03/28/2020 02:22 am »
Anybody getting the vibe this is a love child of F9/ 2nd stage & Dragon 1 & 2? Does the whole spacecraft need to be in the fairing? Could it be half in & half out? If so could they stow a full unpressurized Express Rack?

Yes, I get that vibe. I've been wondering if the rocket system will be a two-stage or a three-stage vehicle, counting the first stage core and side boosters as one stage.
Retired, working interesting problems

Offline ZChris13

Re: SpaceX Dragon XL
« Reply #75 on: 03/28/2020 02:33 am »
Anybody getting the vibe this is a love child of F9/ 2nd stage & Dragon 1 & 2? Does the whole spacecraft need to be in the fairing? Could it be half in & half out? If so could they stow a full unpressurized Express Rack?

Yes, I get that vibe. I've been wondering if the rocket system will be a two-stage or a three-stage vehicle, counting the first stage core and side boosters as one stage.
There's some comments in the announcement and on some captions that indicate it will be a three and a half stage vehicle, with the side boosters as a half-stage.

EDIT: drawing this conclusion from the "deployed in high earth orbit" language, Dragon XL with it's own dragon draco propulsion counting as the third stage
« Last Edit: 03/28/2020 04:12 am by ZChris13 »

Offline John Alan

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Re: SpaceX Dragon XL
« Reply #76 on: 03/28/2020 02:43 am »
Dragon XL is its own 3rd stage... IMHO...
The question is just how much fuel is on board... Delta-v with 5 tonnes of cargo...
Gross weight at separation from S2...
THAT is the question... :-\

It's cargo... Is there some hurry to get it into Lunar orbit in like 3 days?
My guess, no... more like a week or two will be fine with NASA...
And on the way back in "garbage truck" mode... take a month or two to reenter in a controlled manner.

On edit...
What has me intrigued, is what else might some other customer use DXL for in LEO...
Assuming SS/SH takes a while of course...

« Last Edit: 03/28/2020 03:05 am by John Alan »

Offline Tomness

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Re: SpaceX Dragon XL
« Reply #77 on: 03/28/2020 03:03 am »
Falcon 9 could launch a full MPLM to orbit and still be recovered. If you put like a Cygnus back end on it, you'd have way more cargo capability than needed.

The Shuttle could not deliver 20,000 kg of pressurized upmass to ISS. A fully loaded MPLM held more like 13,000 kg of cargo.

Assuming $500M for a Shuttle launch, that works out to $38,500/kg.
.

Multiple errors in your post. A fully loaded MPLM weighed between 13 to 14 metric tons, including cargo. MPLM's empty weight was a little over 4,000 kg. So, that boiles down to just 9,000 to 10,000 kg of cargo capacity for a single MPLM.

https://www.nasa.gov/mission_pages/station/structure/elements/mplm.html

Also, space shuttle historic overviews have shown that the average shuttle mission cost roughly $1B.

These two figures combined boil down to something like $100,000/kg. for cargo-to-ISS via shuttle. That is substantially more expensive than CRS-1 (and CRS-2).

Cross posting from the CRS2 thread.
Since NASA & SpaceX announced Dragon XL for gateway could they use this for ISS first?

Makes you now wonder about the private Dragon flight if it could dock to Dragon XL it could have an awesome week in space.

Offline yg1968

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Re: SpaceX Dragon XL
« Reply #78 on: 03/28/2020 03:15 am »
I'm guessing these have to be fully expendable Falcon Heavy launches, to get 5 tonnes of cargo to lunar orbit in a spacecraft that has to weigh 5-times-something tonnes - maybe 20 tonnes at TLI with about 1/4th of that mass needed for lunar orbit insertion.

 - Ed Kyle

Incidentally, NASA's requirements were for 3,400 kg of pressurized cargo and 1,000 kg of unpressurized cargo:

Quote from: NASA (Attachment_01_GLS_SOW)
4.1.1.1 Contractor shall provide a capability to deliver a minimum of 3,400 kg of pressurized cargo to the Gateway within the overall constraints as defined in GLS-RQMT-001.

4.1.3.1 Contractor shall provide a capability to deliver a minimum of 1,000 kg of unpressurized cargo to the Gateway within the overall constraints as defined in GLS-RQMT-001.

https://forum.nasaspaceflight.com/index.php?topic=48353.msg2018139#msg2018139
« Last Edit: 03/28/2020 03:22 am by yg1968 »

Offline russianhalo117

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Re: SpaceX Dragon XL
« Reply #79 on: 03/28/2020 03:18 am »
Anybody getting the vibe this is a love child of F9/ 2nd stage & Dragon 1 & 2? Does the whole spacecraft need to be in the fairing? Could it be half in & half out? If so could they stow a full unpressurized Express Rack?

Yes, I get that vibe. I've been wondering if the rocket system will be a two-stage or a three-stage vehicle, counting the first stage core and side boosters as one stage.
Boosters are Stage 0 for majority of US rockets (includes missiles and sounding rockets.

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