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: Robotbeat on 04/29/2018 03:20 amFalcon 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.Quote from: woods170 on 04/29/2018 05:50 pmQuote from: Steven Pietrobon on 04/29/2018 02:10 amQuote from: envy887 on 04/28/2018 05:26 pmThe 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.htmlAlso, 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.
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.
Quote from: Steven Pietrobon on 04/29/2018 02:10 amQuote from: envy887 on 04/28/2018 05:26 pmThe 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.htmlAlso, 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).
Quote from: envy887 on 04/28/2018 05:26 pmThe 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.
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.
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: 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-1.5037522
[...]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 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.
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 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.
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/countSpaceX 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 Dragon23. 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.
Quote from: daedalus1 on 03/28/2020 07:58 amQuote 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.Like the ocean, vast and infinite! Waste will never be an issue. If XL's have a life beyond the Gateway, I can't see them be disposed of. Refueling or recovery are perfectly doable.Thinking longer term, XL (DXL?) gives SpaceX a very nice service vehicle for their Starship fleet.
... Even transits through asteroid belt need to calculate potential collisions. You don't just transit blindly. ...
Yet another interesting Dragon variant is proposed. Huzzah! Space is big - cis-lunar space is not infinite. Even transits through asteroid belt need to calculate potential collisions. You don't just transit blindly
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.
