Tullius

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About Tullius

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  1. They were a Lunar XPrize team until a few days ago, when they finally gave up, since they would only be able to launch their mission in 2018, and the deadline for the XPrize is end of 2017. Source: http://www.spiegel.de/wissenschaft/weltall/mond-mission-part-time-scientists-gewinnen-vodafone-als-partner-a-1139371.html (in German)
  2. You also have that risk, if the ship is standing still. And New Glenn might be able to cope better with it, since it will be programmed that the landing spot will be constantly updated during flight, unlike Falcon 9, where the landing spot is probably somewhat hardcoded before liftoff.
  3. Ok, didn't thought that they might indeed want to land on a moving ship. Increases the difficulty, since that gives no predefined landing spot.
  4. I guess the barge won't move during the landing attempt. In the case of SpaceX, the barges can't move themselves (except for keeping themselves exactly at the landing spot), which means that they need tugs to get the platform out into the ocean and back into the harbor. Blue Origin uses instead a ship, which allows them to not need tugs, making the whole procedure simpler (and also they probably need a bigger landing platform for New Glenn than Falcon 9, which would mean bigger tugs). The only disadvantage is that a ship is probably more expensive, if you risk punching holes into it...
  5. https://en.wikipedia.org/wiki/Hill_sphere i.e. Hill spheres are a thing in real life. It is an approximation of the distance at which a moon or satellite may be in orbit around another body (the moon needs to lie inside the body's Hill sphere). In practice, the limit at which a body may be in stable orbit is only about a third to a half of the radius of the Hill sphere.
  6. The heaviest commsats already weigh more than 5 tonnes and are mostly limited in terms of weight by their launch vehicles. And considering Blue Origin probably wants a bit of extra margin for the first flight, using New Glenn for a commsat launch isn't the worst idea (especially, since Echostar probably gets a nice price for a launch on top of an untested rocket).
  7. Why? Those additionnal flights were made possible by of the reduction in the Russian crews (from 3 to 2), due to budget cuts. So instead of flying some Soyuz missions with only 2 crew members, NASA purchased the third seat. Also both Dragon 2 and CST-100 are intended to do their first manned flight in May, resp. August 2018. CST-100s first flight to ISS is even only scheduled for December 2018. In short, the flights that NASA booked now will occur before Dragon and CST-100 can fly according to a regular schedule to ISS. And the option of the 2019 flights is if the schedules at SpaceX or Boeing will slip. Considering that by this 4 out of 6 permanent crew members will either be US or from US partners, there is maybe more available for SpaceX and Boeing than replacing 2 out of 4 Soyuz flights done every year.
  8. Don't fall for the tricks of SpaceX's PR department: They want to be seen as the rock stars, while in fact there are lot of companies out there doing this kind of stuff. The only difference is that SpaceX has the funding, and for the funding they need the PR stunts. SpaceX won't enter lunar orbit, as did Apollo 8 or Orion will. But still, it will a PR blow for NASA. But also remember that SpaceX needs NASA, due to the billions of dollars NASA already pumped and still will pump into SpaceX. Without NASA, Musk would still play with toy rockets instead of real rockets. With that background, it is also no wonder that, according to Scott Manley, SpaceX is offering NASA the two seats on this lunar flight, forcing the two billionaires to a later flight, if NASA is willing to pay. This clearly shows who has the most money, and that is not the two billionaires. NASA won't drop SpaceX, even if it would mean that it would lose a "competitor", since that would mean that they lose their chance of a pure American access to the ISS and, let's not forget, SpaceX is responsible for 5000 jobs in the space industry, so the Senate wouldn't tolerate such a behavior from NASA. So NASA might decide to not fund ITS, in order to keep SpaceX away from the big milestones, but they won't drop the support for SpaceX's LEO operations. So don't wonder, if, during the coverage of that Moon mission, SpaceX is constantly thanking NASA for their support, even if NASAs biggest contribution would be the communication links.
  9. Even if they would get the price down to shuttle levels for a number of launches equal to the one of the shuttle, they will never get the number of missions. Okay, NASA may send one probe (due to the payload capacity of SLS, of the billion dollar class) per year for the next 30 years with SLS, do a dozen missions to the Moon and 2-3 missions to Mars, before the Senate decides that they should shut down the program, since they achieved all goals (cf. Apollo). But that is still at most some 75 missions (and that is still a very generous amount), i.e. half of the shuttles launches. But you also need to put it into perspective: the shuttle needed much more flights to achieve its goals: 22 Spacelab missions, 10 to Mir, 5 for Hubble, 37 to ISS, and numerous other science missions or satellite transports. Every goal that the shuttle achieved or tried to achieve relied on numerous launches, as otherwise they wouldn't be worthwile. Would it be a problem, if one Mars mission costs as much as the entire American contribution of ISS (37 shuttle missions, all of the American modules etc.), i.e. some 100 billion dollars?
  10. The descent stage was pretty much dry after landing, i.e. the extra boost would have been mostly irrelevant. Also, as was the case with the extended nozzle on Apollo 15, there was quite some risk that the nozzle would be damaged on landing, making it impossible to use the engine again.
  11. Sure, they might miss the schedule (or even it is quite likely that they will miss it), but it is theoretically possible. Depends on how it is done. If the Senate decides to cancel SLS in favour of private projects, then there is nothing preventing them from doing it. And relating this to the current administration is a bit difficult, since nobody really knows how their intentions are: Sure they want to save money, but at the same time they seem to have some interest in a manned Moon mission (even if it is just for the pictures on TV), since they are investigating for a manned EM-1. For the second part: NASA is free to create the requirements they want, i.e. to adapt them to ITS. Sure, they shouldn't make it too obvious, but finding some scientists saying that, if they want to go to Mars, they should "either go big or go home", should not be that hard. Also, there is nothing preventing them from buying part of an ITS mission to Mars, i.e. only pay for 2-3 of 6 seats. For example, in case of Red Dragon, NASA essentially gifted SpaceX the necessary capacity of the Deep Space Network (in return, NASA gets scientific and technical results of the mission). But in the end, I don't think that it would be really cheaper for NASA to fund commercial missions than doing it by themselfs: The commercial resupply missions will cost NASA a few billion dollars, and the commercial crew program already granted Boeing nearly 5 billion dollars and SpaceX over 3 billion dollars even before the first flight. Comparing those values to those of SLS program which will have cost some 40-50 billion dollars by the time of the prospected EM-2 mission, it is actually not that expensive, considering the relative size of the project. Do you really think that companies like SpaceX would be able to develop ITS for NASA at less than 10 times the cost of the Commercial Crew program? And grant to a company like Blue Origin the same support for the competition? So I think that the Senate, if they want to do the sensible thing (which is not guaranteed), will stick to SLS, if they want the US to do more in space than ISS and probes.
  12. Why shouldn't SpaceX be able to pull this stunt off? By mid 2018, they have a good chance that they have a flight-proven rocket (Falcon Heavy) and capsule (Dragon). Sure, they won't have flown a BEO mission, but that should only be a minor hindrance. However, one must understand about this is that it isn't redoing Apollo 8 (like SLS+Orion on EM-2), but rather the Soviet Zond missions and their unmanned lunar flybys (hopefully with a better success rate than 1 in 5). And like the Zonds with their modified Soyuz capsules on Proton rockets, Dragons lunar flyby will be a dead end in terms of space craft development, since it is the maximum the given hardware is able to do. Sure, they have a good chance of beating NASA in putting humans into lunar space, but NASA will do it with hardware that after further development can support Moon landings. However, one should not underestimate the public opinion and the opinion of the Trump administration: If a private company can do it, why spend such a ridiculous amount of money on NASAs manned lunar (and beyond) program? But if SLS is cancelled and they still want missions outside of LEO, they have to fund a private company. In short, SpaceX will get its ITS program funded by NASA, just like they got funded their Dragon and Falcon program (2.6 billion dollars + technical assistance for Dragon to ISS!). I don't know, if Musk is speculating on this happening, but it would sure as hell solve his problem of funding ITS. This might also be the reason, why NASA is in some sense pushed to do EM-1 manned: They can show that they are just as good as SpaceX and they have the more capable hardware.
  13. And a heat shield capable of reentry from the Moon, and all of the rest. Okay, they may skip the larger service module with extra propulsion, if they just go for a free return. This sounds a bit like the Russian Zond Moon program: Get "some" spacecraft with "some" astronauts on "some" trip to the Moon so that we can say we have beaten NASA.
  14. I heard somewhere that Apollo was designed to a failure rate of 1 in 1000. So I would be surprised if the Shuttle wasn't designed to some similar figure. The problem is not really the calculation of risk, you have to do it (there is no way of doing it otherwise). And generally, you overestimate the risks (as in: You guess that an engine fails 1 in 1000 launches, but you enter a failure rate of 1 in 500 into the calculation). The problem is that you are going to miss some possible failure modes or misidentify the actual failure rate of a component. Nobody really bothered about the risk created by the O-ring design until after Challenger. The probability that the Shuttle's heat shield could be fatally damaged by foam from the external tank was also underestimated until Columbia. In hindsight, NASA estimated the risk of failure for the Shuttle during the first flights to be 1 in 9, while the later ones were 1 in 90 (i.e. barely acceptable). But that is in hindsight and doesn't help with the development of a spacecraft, other than showing that targeting such an extreme reliability as 1 in 500 or more is a good idea. Doing lots of test flights or man-rating a cargo rocket, makes it easier to estimate the risks, since you can analyse the results of those flights. But this in turn also means that you can use sharper estimates on the risk of different failures, and thereby reduce the amount of over-engineering to be really sure that you achieve the desired reliability, and thereby making the development cheaper.
  15. Peacekeeper weighs approx. 90 tonnes, i.e the calculation is something along the lines of (90+4)/(90+15)*2.5=2.24. So there is still plenty of TWR to spare at takeoff.