Tullius

Members
  • Content count

    75
  • Joined

  • Last visited

Everything posted by Tullius

  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.
  16. For the LES test, you only need to go suborbital until MaxQ, i.e. you only need to reach some 15km of altitude. And considering that a Peacekeeper has a TWR of 2.5 (twice that of Saturn V), i.e. much bigger than what SLS probably will have, you can add a considerable payload before it won't be able to reach MaxQ at the desired altitude and speed.
  17. It is a bit weird to imagine that the cargo needs to be adapted to the transporter, instead of the transporter being developped for a given cargo. But in the end, Dragon was also developped for manned flight, so there were restrictions on how the cargo version could look like, if they wanted to keep them similar. Maybe in the future, cargo transport will be adapted to Dragons specialities or secondary payloads such as cubesats (which wouldn't be surprising, since there are cubesats that were set out by the ISS), which will add to the efficiency. And in the end, let's not forget that it is mostly about the cost per kg to ISS (and optionnally back). 2 tonnes is a lot, but there are biological experiments being done on ISS, for which it would probably be nice to analyse them down on Earth. But the only other options of cargo return are the small cargo return capsule that Progress can transport or together with the astronauts inside Soyuz, i.e. very limited. So Dragons huge return capability allows for a lot more flexibility for the return of experiments. Also, as above, we are speaking of the cargo version of a manned space craft, i.e. adding that huge return payload was very cheap in development cost.
  18. The final selection will be based on the training camps. So it is not just being good at a mobile game, as the final selection will still depend on the usual astronaut selection process. The fact that most astronauts are either jet pilots, scientists or engineers is mostly due to them already bringing their knowledge to the space program. Jet pilots, especially if they are test pilots, have knowlegde in flying difficult to fly aircraft, i.e. they are already used to similar situations as flying a space craft (and absolutely required for a Space Shuttle). On the other hand scientists and engineers are brought to the ISS to do what they know best: do science. Also it is not like there is no precedent: space tourists and NASA's "Teacher in Space"-program all send people to space that had no special qualification for becoming an astronaut, besides being physically and mentally fit enough.
  19. There are two reasons why the answer to the first question is no: Kourou probably lacks the necessary infrastracture for manned launches. The Soyuz rockets launched from Kourou are the newer Soyuz-2 version, which did not yet see a manned launch. (Although it is already used for Progress) Nothing that can't change in the future. But a manned launch probably won't happen soon. Considering performance enhancements: A Soyuz launched from Kourou can put 2.8 tonnes into GTO, while the same rocket from Baikonur can only put 1.7 tonnes into GTO. But as Nibb said, ISS has an inclined orbit, which was specifically chosen with launches from Baikonur in mind. So there would be no advantage. As to manned Soyuz launches not targeting ISS from Kourou: ESA is used to buying its seats from the Americans. And considering that in the US, there are two companies hoping to sell manned launches (rocket, spacecraft and launch pad in one complete pack) in the future, I don't see the point as to why the Europeans should invest money into possible manned Soyuz launches, as they almost certainly would be a quite rare occurence.
  20. For those discussions, it doesn't matter if only 1 astronaut died or 7. At the time of the accidents, the Shuttle had already proved its capability and they were necessary for the construction of the ISS. So after some analysis of the causes, they continued on. For SLS it would mean a loss on the first flight. There would be no evidence that it is mostly safe. If they do an unmanned flight first and fail, there won't be a major backlash so that they could continue on and do a second unmanned test. If they do an unmanned flight first and the subsequent manned flight fails, they can always tell the public and congress that some problem with fatal consequences occured, but that there is no general problem with the spacecraft and rocket, since the unmanned test worked. Also remember that before EM-1 (especially if it is pushed back to do it manned), it is expected that both Dragon and CST-100 had their first manned flight tests, i.e. in the eyes of the public the US already has the capability of manned space flight at much lower cost. Sure, they are much less capable, but will that message get through to the public? If they really want to make Trump happy by giving him a manned launch during his first term, they should try to launch EM-2 in early 2020 (i.e. ideally situated before the elections). Considering that EM-1 should happen in 2018, EM-2 is planned for somewhere between 2021 and 2025 and that the reason for this long gap is probably lack of sufficient funding, that could be possible if they get Trump to provide them with extra funding.
  21. The main problem is: What happens afterwards if the first manned SLS flight fails and kills its crew? Will NASA be allowed to continue on (after working out the problems), just like the Russians did after the Soyuz-1 failure? Or will NASAs entire program with humane spaceflight beyond LEO be at risk of being cancelled?
  22. Because it isn't picturing Mars, but Saturn's moon Enceladus, which is known to have some sort of geysirs. There also exists a render of ITS on Jupiter's moon Europa. Let's see if Red Dragon does a Schiaparelli landing on Mars or not (if it even reaches Mars ), before we start bothering abouts Musk's visions.
  23. I quote wikipedia (https://en.wikipedia.org/wiki/Splashdown): The inflatable balloons were only added after the sinking of Liberty Bell 7. As to the question "Will CST-100 float endlessly without balloons?": CST-100 is designed to be airtight for more than 6 month in space, so there had to be something on the capsule which would get easily destroyed by seawater. The 6 balloons below the capsule are the same as those used to dampen the landing on land. So they are probably pretty tough. As to the 2 purple balloons on top, they are intended to right the capsule, if it flips over in the water, to allow for an easier recovery.
  24. If you blow a hole in a capsule before it is attached to the helicopter, a capsule will sink? Otherwise you need a lot of bad luck that a capsule that only half an hour before was still airtight, will suddenly let water flow in.
  25. I was mostly relating it to the fact that if the suits had to be orange so the astronauts would be spotted easier in the water, there also has to be equipment onboard to allow them to survive in the water. The new suit is, if the helmet is open (as it need be if you are not connected to the spacecraft, not watertight and, even worse, it will quickly fill with water, so you need to have life vests or life rafts onboard, which adds extra weight, which could also be used to be even more certain that the capsule could not sink, completely forgoing the option of the astronauts leaving the capsule.