Space X to build reusable launch vehicle
Two small bits of data.
1. From the FH info on Spacex's website, its liquid boosters have a wet/dry mass fraction over 30.
Because those boosters are essentially Falcon 9 (block 3?) first stages, that means they have to have about the same ratio. If FH wet mass at lift-off is 1.400 mt and 53 mt are cargo, the three F9 cores initial mass has to probably be under 1.200 mt, or 400 mt each. That'd give a max dry mass of 13.3 mt (in a video from SpaceX they say the F9 block 1 first stage tank plus engine assembly weights 9,000 lb, add nine 630 kg engines, total 9,752 kg; F9 block 3 tank is bigger, although Merlin 1D are lighter).
2. Falcon 9 first stage should be able to withstand more than 10 g of axial acceleration.
A few seconds before staging they turn off 2 of the 9 engines to avoid forces surpassing 7 gs, but at that moment the first stage structure is supporting itself plus the weight of the second and cargo (40-45 mt per 7 g). That means over 300 mt of force. If in its way down its mass is reduced to 10-15 mt, it should be able to accept quite more than 10 gs.
If the stage broke during reentry it should be because of lateral forces not axial.
1. From the FH info on Spacex's website, its liquid boosters have a wet/dry mass fraction over 30.
Because those boosters are essentially Falcon 9 (block 3?) first stages, that means they have to have about the same ratio. If FH wet mass at lift-off is 1.400 mt and 53 mt are cargo, the three F9 cores initial mass has to probably be under 1.200 mt, or 400 mt each. That'd give a max dry mass of 13.3 mt (in a video from SpaceX they say the F9 block 1 first stage tank plus engine assembly weights 9,000 lb, add nine 630 kg engines, total 9,752 kg; F9 block 3 tank is bigger, although Merlin 1D are lighter).
2. Falcon 9 first stage should be able to withstand more than 10 g of axial acceleration.
A few seconds before staging they turn off 2 of the 9 engines to avoid forces surpassing 7 gs, but at that moment the first stage structure is supporting itself plus the weight of the second and cargo (40-45 mt per 7 g). That means over 300 mt of force. If in its way down its mass is reduced to 10-15 mt, it should be able to accept quite more than 10 gs.
If the stage broke during reentry it should be because of lateral forces not axial.
"The problem is not what we don't know, but what we do know [that] isn't so" (Mark Twain)
Even at the lesser performance of kerosine-LOX that sounds like a SSTO with useful payload mass ratio. Anyone have the numbers to figure how that payload would compare to the baseline 2 stage Falcon 9? But it would make stage recovery much harder.charliem wrote:1. From the FH info on Spacex's website, its liquid boosters have a wet/dry mass fraction over 30.
Certainly. With a mass ratio of 30 and an Isp of 280 s you can get to orbit, but with almost zero margin for payload.hanelyp wrote:Even at the lesser performance of kerosine-LOX that sounds like a SSTO with useful payload mass ratio.
290 s would be much better. It'd imply 15 mt to orbit (from 400 at lift-off). Take off 10-12 for the vehicle and you are left with 3-5 mt.
Merlin's 1D effective Isp has to be higher than 280 (it's value at sea level), and under 310 (vacuum). Anyone knows how to estimate the effective Isp?
Changing the subject, this article in Air & Space about SpaceX is quite good: http://www.airspacemag.com/space-explor ... c=y&page=1
"The problem is not what we don't know, but what we do know [that] isn't so" (Mark Twain)
According to this website:
http://www.spacelaunchreport.com/falcon9.html
SL Isp is 280 s and vac Isp is 309 sec.
http://www.spacelaunchreport.com/falcon9.html
SL Isp is 280 s and vac Isp is 309 sec.
There are some striking similarities between SpaceX and Blue Origin.
Both were founded by internet big shots, Jeff Bezos from Amazon (CEO), and Elon Musk from PayPal (co-founder). Both say one of their main goals, at least as an intermediate step, is to significantly cheaper access to space.
Even on engineering both seem to have quite similar visions, although SpaceX looks to be ahead.
Blue Origin started developing various VTVL research vehicles, and they declared they want to evolve it into a SSTO to maximize reusability and minimize cost.
SpaceX already have a TSTO launcher and now is studying the possibility of building a VTVL version (although not, at least at first, in a single stage to orbit configuration). I wonder if a true SSTO is not the next logical step.
Both were founded by internet big shots, Jeff Bezos from Amazon (CEO), and Elon Musk from PayPal (co-founder). Both say one of their main goals, at least as an intermediate step, is to significantly cheaper access to space.
Even on engineering both seem to have quite similar visions, although SpaceX looks to be ahead.
Blue Origin started developing various VTVL research vehicles, and they declared they want to evolve it into a SSTO to maximize reusability and minimize cost.
SpaceX already have a TSTO launcher and now is studying the possibility of building a VTVL version (although not, at least at first, in a single stage to orbit configuration). I wonder if a true SSTO is not the next logical step.
"The problem is not what we don't know, but what we do know [that] isn't so" (Mark Twain)
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GIThruster
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I don't think there was note of what is expected with the Heavy and Super-Heavy. With the development path SpaceX is using, looks like the Super-Heavy could be had for less than $1 billion--less that 1/35 what NASA plans to spend on SLS, or probably less than 1/50 or 2% of what it will actually spend. So why is NASA developing a launch vehicle instead of an interplanetary vehicle to go on the Falcon Super-Heavy? Wouldn't the money be better spent on something like TRITON and NautilusX
http://www.youtube.com/watch?v=DtoADdSr ... re=related
http://space.about.com/b/2011/02/25/nas ... -craft.htm
http://www.youtube.com/watch?v=DtoADdSr ... re=related
http://space.about.com/b/2011/02/25/nas ... -craft.htm
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
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kunkmiester
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That should have been the rule for decades--build a mission, contract for launch. As soon as the first satellite was up, we should have been privatizing. At the least after Apollo. Even by that time, space launch was becoming mainstream, just like NACA(or whatever the old acronym was) did, once you get to commercial feasibility, put out bids for contracts, and move back to the cutting edge.
Assuming you think you need gov at all--it's headsmackingly obvious that long term research is needed, and corporations can earn brownie points by funding university programs for that, and you'd get the same effect, although since the funding source is different, program and idea priority would be different. YMMV.
People assume that without government, certain things wouldn't get done. But government does them because someone thinks they need to get done, and so even without it, someone is going to make sure they get done, one way or another.
Assuming you think you need gov at all--it's headsmackingly obvious that long term research is needed, and corporations can earn brownie points by funding university programs for that, and you'd get the same effect, although since the funding source is different, program and idea priority would be different. YMMV.
People assume that without government, certain things wouldn't get done. But government does them because someone thinks they need to get done, and so even without it, someone is going to make sure they get done, one way or another.
Evil is evil, no matter how small
Because it is not about doing the best possible spaceprogramme, but about directing the pork to the usual suspects. In this case mostly ATK...So why is NASA developing a launch vehicle instead of an interplanetary vehicle to go on the Falcon Super-Heavy? Wouldn't the money be better spent on something like TRITON and NautilusX
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GIThruster
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That is certainly true. Congress pushed SLS to keep people employed. I just read at another source that the SLS is now being estimated to cost $60B to develop, plus operating costs which will all be fantastically higher than those for commercial launch systems. If someone doesn't stop the madness, we're going to have no space program again.
Space Quarterly did a couple excellent pieces on the SLS issue, and one is predicting that because SLS and JWST are competing for shrinking funds, and because the telescope is well along on its way and cannot be replaced by commercial systems, that Webb will push SLS out of existence. That would be a very good thing, IMHO.
Still doesn't get us TRITON or Nautilus-X though.
Space Quarterly did a couple excellent pieces on the SLS issue, and one is predicting that because SLS and JWST are competing for shrinking funds, and because the telescope is well along on its way and cannot be replaced by commercial systems, that Webb will push SLS out of existence. That would be a very good thing, IMHO.
Still doesn't get us TRITON or Nautilus-X though.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
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GIThruster
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out from SpaceX in the last hour:
NASA ANNOUNCES: DRAGON TO THE SPACE STATION
December 8 2011, marked the one year anniversary of Dragon’s first Commercial Orbital Transportation Services (COTS) demonstration flight. The flight made history as SpaceX became the only commercial company to successfully return a spacecraft from orbit. This feat had previously been accomplished only by five nations and the European Space Agency.
We are now preparing the Dragon spacecraft for yet another historic flight – becoming the first commercial vehicle in history to visit the International Space Station (ISS)!
NASA recently announced February 7, 2012, as our new target launch date for the upcoming mission. In addition, NASA officially confirmed that SpaceX will be allowed to complete the objectives of COTS 2 and COTS 3 in a single mission.
This means Dragon will perform all of the COTS 2 mission objectives which include numerous operations in the vicinity of the ISS, and will then perform the COTS 3 objectives. These include approach, berthing with the ISS, astronauts opening Dragon and unloading cargo, and finally, astronauts closing the spacecraft and sending it back to Earth for recovery from the Pacific Ocean off the coast of California.
This mission marks a major milestone in American spaceflight. While our first missions to the ISS will be to transport cargo, both Falcon 9 and Dragon were designed to ultimately transport astronauts. Every trip we make to the ISS from this point forward gets us closer to that goal. SpaceX is incredibly excited for what the future holds and as always, we greatly appreciate NASA’s continued support and partnership in this process.
THE COTS 2/3 DEMONSTRATION MISSION
Just as Dragon’s first mission to orbit and back involved a level of effort equal to launching the first Falcon 9, preparing Dragon for two weeks of operation in space and for approach and berthing with the ISS poses new challenges. Meeting them requires a large amount of detailed planning and careful execution.
Each launch day will have just one narrow liftoff window—no more than a few minutes—in order to synchronize Dragon’s flight with the orbit of the ISS. Catching up to the ISS will take from one to three days. Once there, Dragon will begin the COTS 2 demonstrations to show proper performance and control in the vicinity of the ISS, while remaining outside the Station’s safe zone.
COTS 2 objectives include Dragon demonstrating safe operations in the vicinity of the ISS. Actual zone of operations is greater than shown in the illustration above. Illustration: NASA / SpaceX.
During the entire time Dragon is in the vicinity of the ISS, Station astronauts will be in direct communication with Dragon and will be able to monitor the spacecraft as well as issue spacecraft commands.
After successfully completing the COTS 2 requirements, Dragon will receive approval to begin the COTS 3 activities, gradually approaching the ISS from the radial direction (toward the Earth), while under constant observation.
As part of the COTS 3 objectives Dragon approaches the ISS, so astronauts can reach it with the robotic arm. Illustration: NASA / SpaceX.
Dragon will approach to within a few meters of the ISS, allowing astronauts to reach out and grapple Dragon with the Station’s robotic arm and then maneuver it carefully into place. The entire process will take a few hours.
The astronaut operating the robot arm aboard the ISS will move Dragon into position at the berthing port where it will be locked in place. Illustration: NASA / SpaceX.
Once in place, Station astronauts will equalize the pressure between the ISS and Dragon, open the hatches, enter the vehicle and begin unloading Dragon’s cargo.
In the SpaceX cleanroom the crew prepares the COTS 2/3 Dragon for its visit to the ISS. View looking through the forward hatch from the ISS side of the berthing adapter. Photo: Roger Gilbertson / SpaceX
After Dragon spends about a week berthed at the ISS, astronauts will reverse the process, loading Dragon with cargo for return to Earth, sealing the hatches, and un-berthing Dragon using the robotic arm.
Dragon will then depart from the ISS and return to Earth within a day or so, and the SpaceX recovery crew will meet it at splash down in the Pacific Ocean off the coast of California.
PREPARING FOR LAUNCH AT THE CAPE
As previously reported, both the Falcon 9 launch vehicle and the Dragon spacecraft that will fly in the COTS Demo 2/3 mission have been delivered to our launch complex in Cape Canaveral, Florida. Falcon 9’s first stage, second stage, and interstage were integrated and rolled out for two separate wet dress rehearsals in which SpaceX engineers performed the entire countdown sequence up until the moment the engines would be fired.
The completed Falcon 9 COTS Demo 2/3 vehicle in the SpaceX hangar at Cape Canaveral, Florida. Photo: Mike Sheehan / SpaceX.
The Dragon COTS Demo 2/3 spacecraft and trunk have also been delivered to our launch pad and are undergoing final processing for flight.
The COTS Demo 2/3 Dragon spacecraft at Cape Canaveral. Photo: SpaceX
NASA ANNOUNCES: DRAGON TO THE SPACE STATION
December 8 2011, marked the one year anniversary of Dragon’s first Commercial Orbital Transportation Services (COTS) demonstration flight. The flight made history as SpaceX became the only commercial company to successfully return a spacecraft from orbit. This feat had previously been accomplished only by five nations and the European Space Agency.
We are now preparing the Dragon spacecraft for yet another historic flight – becoming the first commercial vehicle in history to visit the International Space Station (ISS)!
NASA recently announced February 7, 2012, as our new target launch date for the upcoming mission. In addition, NASA officially confirmed that SpaceX will be allowed to complete the objectives of COTS 2 and COTS 3 in a single mission.
This means Dragon will perform all of the COTS 2 mission objectives which include numerous operations in the vicinity of the ISS, and will then perform the COTS 3 objectives. These include approach, berthing with the ISS, astronauts opening Dragon and unloading cargo, and finally, astronauts closing the spacecraft and sending it back to Earth for recovery from the Pacific Ocean off the coast of California.
This mission marks a major milestone in American spaceflight. While our first missions to the ISS will be to transport cargo, both Falcon 9 and Dragon were designed to ultimately transport astronauts. Every trip we make to the ISS from this point forward gets us closer to that goal. SpaceX is incredibly excited for what the future holds and as always, we greatly appreciate NASA’s continued support and partnership in this process.
THE COTS 2/3 DEMONSTRATION MISSION
Just as Dragon’s first mission to orbit and back involved a level of effort equal to launching the first Falcon 9, preparing Dragon for two weeks of operation in space and for approach and berthing with the ISS poses new challenges. Meeting them requires a large amount of detailed planning and careful execution.
Each launch day will have just one narrow liftoff window—no more than a few minutes—in order to synchronize Dragon’s flight with the orbit of the ISS. Catching up to the ISS will take from one to three days. Once there, Dragon will begin the COTS 2 demonstrations to show proper performance and control in the vicinity of the ISS, while remaining outside the Station’s safe zone.
COTS 2 objectives include Dragon demonstrating safe operations in the vicinity of the ISS. Actual zone of operations is greater than shown in the illustration above. Illustration: NASA / SpaceX.
During the entire time Dragon is in the vicinity of the ISS, Station astronauts will be in direct communication with Dragon and will be able to monitor the spacecraft as well as issue spacecraft commands.
After successfully completing the COTS 2 requirements, Dragon will receive approval to begin the COTS 3 activities, gradually approaching the ISS from the radial direction (toward the Earth), while under constant observation.
As part of the COTS 3 objectives Dragon approaches the ISS, so astronauts can reach it with the robotic arm. Illustration: NASA / SpaceX.
Dragon will approach to within a few meters of the ISS, allowing astronauts to reach out and grapple Dragon with the Station’s robotic arm and then maneuver it carefully into place. The entire process will take a few hours.
The astronaut operating the robot arm aboard the ISS will move Dragon into position at the berthing port where it will be locked in place. Illustration: NASA / SpaceX.
Once in place, Station astronauts will equalize the pressure between the ISS and Dragon, open the hatches, enter the vehicle and begin unloading Dragon’s cargo.
In the SpaceX cleanroom the crew prepares the COTS 2/3 Dragon for its visit to the ISS. View looking through the forward hatch from the ISS side of the berthing adapter. Photo: Roger Gilbertson / SpaceX
After Dragon spends about a week berthed at the ISS, astronauts will reverse the process, loading Dragon with cargo for return to Earth, sealing the hatches, and un-berthing Dragon using the robotic arm.
Dragon will then depart from the ISS and return to Earth within a day or so, and the SpaceX recovery crew will meet it at splash down in the Pacific Ocean off the coast of California.
PREPARING FOR LAUNCH AT THE CAPE
As previously reported, both the Falcon 9 launch vehicle and the Dragon spacecraft that will fly in the COTS Demo 2/3 mission have been delivered to our launch complex in Cape Canaveral, Florida. Falcon 9’s first stage, second stage, and interstage were integrated and rolled out for two separate wet dress rehearsals in which SpaceX engineers performed the entire countdown sequence up until the moment the engines would be fired.
The completed Falcon 9 COTS Demo 2/3 vehicle in the SpaceX hangar at Cape Canaveral, Florida. Photo: Mike Sheehan / SpaceX.
The Dragon COTS Demo 2/3 spacecraft and trunk have also been delivered to our launch pad and are undergoing final processing for flight.
The COTS Demo 2/3 Dragon spacecraft at Cape Canaveral. Photo: SpaceX
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
I guess this means that NASA and the FAA will no wfinally have to shyte or get off the pot on who is going to own commercial space flight certifications for both manned and non-manned. A senior Safety Director for NASA that I talked to last year told me that the "idea" is for NASA to Cert anything that touches a government project (like ISS, or flies government Astronauts), and that the FAA would do everything else. Of course nothing is set in stone because factions in NASA and FAA have different ideas. 
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GIThruster
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IIUC, what this above means with C2 and C3 combined, the Dragon is going to dock with ISS launching February 7. SpaceX had been pushing for this combination for many months and were finally granted. If FAA decides to whine they can, but I don't think they'd get far since NASA is signing off on the flight. (This was delayed because all of the ISS partners likewise needed to sign off on it, and the Russians delayed as long as they could.) It was after all, one of NASA's COTS milestones to do the docking, and SpaceX is saying they're ready ahead of schedule and want to do it now. Apparently they were ready for a November 30 launch for C2/C3 but the launch was slipped because ISS has to have astronauts aboard trained to dock the Dragon and that was delayed because of the Soyuz launch failure.
Just getting NASA to allow the C2/C3 combination is a huge win for SpaceX so long as they deliver. Lets hope so. That would put them very far along the way to human transport to ISS. Afterward would just need some repeatability to gain the necessary rating. Were the certifiers at NASA lax in such things, we'd have Dragons running folks to ISS in 2012.
Just getting NASA to allow the C2/C3 combination is a huge win for SpaceX so long as they deliver. Lets hope so. That would put them very far along the way to human transport to ISS. Afterward would just need some repeatability to gain the necessary rating. Were the certifiers at NASA lax in such things, we'd have Dragons running folks to ISS in 2012.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
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GIThruster
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I highly recommend this awesome interview with Gary Hudson on the concept of reusable launch vehicles. Gary is an undervalued treasure to the space community.
http://www.thespaceshow.com/detail.asp?q=1653
http://www.thespaceshow.com/detail.asp?q=1653
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis