My initial though after seeing the art work for this was that it might have a docking adapter at both ends and a pass through tunnel, like one of the proposed follow ons to the ATV. I don't think this is the case as this would limit the volume for external cargo but it's still an idea for a presumably cheap station/free flyer somewhere in the Earth-Moon system.Sorry only tangentially related to dragon XL, I must try harder
It kinda loses its big significance when you bring Starship into the picture, but Starship - essentially, is still a launch and reentry vehicle, even if used for interplanetary work with long coast times - it will launch on a planet surface and will be landing somewhere.
My questions are:1) Is the cargo volume the same or larger than cargo D2?2) Will part of that 5t of cargo include propellent for transfer?
Quote from: nacnud on 03/27/2020 06:56 pmQuote from: abaddon on 03/27/2020 06:42 pmQuote from: TheRadicalModerate on 03/27/2020 06:39 pmIt looks like an FHE and a plain ol' Dragon 2, even outfitted with a bunch of ECLSS and crew consumables that they don't need, could take 4.5 t to NRHO with no problem. Surely if they stripped out all the crew-critical stuff from D2 it would carry 5 t as-is? Why the redesign?VolumeAnd cost.I can't imagine that the NRE for a new design would amortize over the number of likely Gateway logistics missions. Even if D2 isn't the optimal design, it's one that exists already. That's worth quite a bit.I can understand the volume issue. D2 has only half the pressurized volume of Cygnus.
Quote from: abaddon on 03/27/2020 06:42 pmQuote from: TheRadicalModerate on 03/27/2020 06:39 pmIt looks like an FHE and a plain ol' Dragon 2, even outfitted with a bunch of ECLSS and crew consumables that they don't need, could take 4.5 t to NRHO with no problem. Surely if they stripped out all the crew-critical stuff from D2 it would carry 5 t as-is? Why the redesign?VolumeAnd cost.
Quote from: TheRadicalModerate on 03/27/2020 06:39 pmIt looks like an FHE and a plain ol' Dragon 2, even outfitted with a bunch of ECLSS and crew consumables that they don't need, could take 4.5 t to NRHO with no problem. Surely if they stripped out all the crew-critical stuff from D2 it would carry 5 t as-is? Why the redesign?Volume
It looks like an FHE and a plain ol' Dragon 2, even outfitted with a bunch of ECLSS and crew consumables that they don't need, could take 4.5 t to NRHO with no problem. Surely if they stripped out all the crew-critical stuff from D2 it would carry 5 t as-is? Why the redesign?
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!
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.
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
Quote from: Zed_Noir on 03/28/2020 03:23 amIf NASA requires it. There could be a Dragon XL variant with a grappling fixture and a full size CBM port with minor modification.On that subject and as you probably already know, Canada will be building a robotic arm for Gateway and this arm would be delivered by Dragon XL. https://www.cbc.ca/news/technology/canada-lunar-gateway-1.5037522Quote from: NASA (Attachment_01_GLS_SOW_Annex_A)1.0 The Contractor shall deliver the following DSXR [Deep Space Extravehicular Robotic System] items as unpressurized cargo to Gateway as part of one or more launch packageshttps://forum.nasaspaceflight.com/index.php?topic=48353.msg2018139#msg2018139
If NASA requires it. There could be a Dragon XL variant with a grappling fixture and a full size CBM port with minor modification.
1.0 The Contractor shall deliver the following DSXR [Deep Space Extravehicular Robotic System] items as unpressurized cargo to Gateway as part of one or more launch packages
Quote from: baldusi on 03/28/2020 05:41 amQuote from: John Alan on 03/28/2020 02:43 am[...]And on the way back in "garbage truck" mode... take a month or two to reenter in a controlled manner.[...]Why would it need to reenter for disposal? BEO or Moon-crashing would most probably be cheaper, delta-v wise.It's always bothered me when "we" leave our "stuff" in places they should not be left... JMHO...I smile every time a spacecraft saves enough fuel, or puts itself in a <90day to re-entry orbit...to clean up after itself... Delta-v be damned... figure out how to make it work before you launch it... or just don't...Sacrifice payload or as a last resort, expend the rocket if you have to... Because someday, someone will have to clean up the mess we have made over the last 60+years in space...Again... JMHO...
Quote from: John Alan on 03/28/2020 02:43 am[...]And on the way back in "garbage truck" mode... take a month or two to reenter in a controlled manner.[...]Why would it need to reenter for disposal? BEO or Moon-crashing would most probably be cheaper, delta-v wise.
[...]And on the way back in "garbage truck" mode... take a month or two to reenter in a controlled manner.[...]
Quote from: John Alan on 03/28/2020 06:40 amQuote from: baldusi on 03/28/2020 05:41 amQuote from: John Alan on 03/28/2020 02:43 am[...]And on the way back in "garbage truck" mode... take a month or two to reenter in a controlled manner.[...]Why would it need to reenter for disposal? BEO or Moon-crashing would most probably be cheaper, delta-v wise.It's always bothered me when "we" leave our "stuff" in places they should not be left... JMHO...I smile every time a spacecraft saves enough fuel, or puts itself in a <90day to re-entry orbit...to clean up after itself... Delta-v be damned... figure out how to make it work before you launch it... or just don't...Sacrifice payload or as a last resort, expend the rocket if you have to... Because someday, someone will have to clean up the mess we have made over the last 60+years in space...Again... JMHO... Space is big, I mean really big.
If it is supposed to transfer both pressurized and unpressurized cargo, how could it have docking at both ends?
You could use a Dragon XL docked to lunar gateway as a "impact mass container" and fill it up with defined amounts of no-longer-needed stuff until it reaches its design mass.Once the design mass is reached, you detach on a science mission involving a lunar impact as well as a bunch of telescopes analyzing dust, seismic measurements, etc...This isn't "dumping garbage" - it's "science"!
Quote from: yg1968 on 03/28/2020 03:56 amQuote from: Zed_Noir on 03/28/2020 03:23 amIf NASA requires it. There could be a Dragon XL variant with a grappling fixture and a full size CBM port with minor modification.On that subject and as you probably already know, Canada will be building a robotic arm for Gateway and this arm would be delivered by Dragon XL. https://www.cbc.ca/news/technology/canada-lunar-gateway-1.5037522Quote from: NASA (Attachment_01_GLS_SOW_Annex_A)1.0 The Contractor shall deliver the following DSXR [Deep Space Extravehicular Robotic System] items as unpressurized cargo to Gateway as part of one or more launch packageshttps://forum.nasaspaceflight.com/index.php?topic=48353.msg2018139#msg2018139Which is exactly why there is a grapple fixture on the side of Dragon XL. The deep space Canadarm will "walk" itself off the vehicle, onto the Gateway. The first step it takes from its stowed position is onto a grapple fixture on the side of Dragon XL.
I've been wondering about the FH upmass so I checked SpaceX's web site. It is listed as 63,800kg or 140,660 lb to LEO and 16,800kg or 37,040 lb to Mars. I'm guessing that the mass numbers to Gateway are something in between. That seems like enough upmass capability to satisfy the needs of this mission. The payload just needs maneuvering thrusters like all Dragons before it.