Nibb31
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Posts posted by Nibb31
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24 minutes ago, JoeSchmuckatelli said:
If this is truly correct... Why is it that things in orbit maintain the inertial attitude?
The earth maintains its internal attitude around the sun (hence the seasons) just as a refrigerator would around the earth.
It doesn't. It rotates (hence the day/night cycle).
So does Mercury, or the Moon. They rotate, but their rotation period is the same rate as their orbital period. This can be due to tidal lock and mass irregularities, which seems to be a fairly common occurrence, since we have multiple examples of it in our solar system.
QuoteIf spacetime is truly curved - how is inertial attitude maintained at all? Why doesn't an orbiting object move more like a car on a track? (or orbital rate attitude?)
I don't see how space-time curvature comes into play here. I don't think there are any objects that do not have some kind of rotation in them.
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ATV had pretty much half the internal volume of Salyut and was actually bigger than Tiangong-2 or ESA's Columbus module. It could practically have been its own mini-space-station. It really is a shame they only built 5 of them.
In fact, instead of launching Columbus on a Shuttle, ESA could have outfitted an ATV and permanently docked it to the Russian side.
HTV is missing from that graphic. Especially as it is still flying for 2 more years at least. It fits between Progress and ATV in terms of size, but trades off internal volume for unpressurized cargo.
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9 minutes ago, Cassel said:
So none? And each will have to train for several years, well than slowed don't my hype train for Orion :-/
You don't need training on the procedures when you are the one writing the procedures. As I said, the Astronaut Corps is heavily involved in the Orion development process. Systems training goes along with systems development.
The actual mission training is about 10 months (but depends on the actual work to be done) and starts when a crew has been assigned an actual mission. Unless it is cancelled or postponed, EM-2 is still 4 years away, so they have plenty of time and you can keep your hype train in the station.
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42 minutes ago, Cassel said:
I read an article about Orion and I wondered if NASA is already training any astronauts for Orion's mission? And how long does it take train them?
A number of NASA Astronauts have been actively working at Boeing to develop human interfaces, cabin layout, and procedures. These tasks need to be done before training can start.
Training is the major part of the job of being an astronaut (aside from the above development tasks and public outreach) and most astronauts spend several years training while waiting for a flight assignment. They typically train on systems more than on specific missions. For ISS operations, specific mission training usually takes a couple of months (preparing for specific EVA tasks, running experiments, testing equipment...).
The first astronauts to fly on Orion will most likely be those most experienced with its development, like Young and Crippen were the first to fly Columbia after spending years working on the Shuttle program to develop systems and flight test Enterprise.
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Blue Origin is assembling its rockets at the Cape.
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I think that reusable launchers would probably benefit from being made wider and shorter than they way they are currently designed. I envision something like the old SASSTO or ROMBUS designs from Phil Bono, or the DC-X. There is a slight tradeoff in terms of empty mass and drag by using a wider cylinder or a conical shape, but I have the feeling that making the design more robust is worth it, and since you aren't aiming for SSTO, the first stage doesn't have to be highly optimized for weight.
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23 hours ago, wumpus said:
I was assuming that there was a reasonably steady stream of probes (one every few years) while any human mission would be on "maximum Elon time". Wolf Vishniac created the "Wolf trap" for the Viking missions, and the idea was to provide "food" any Martians and wait to see if anything happened. Unfortunately Wolf Vishniac died in an accident in Antarctica, and any hope of including that experiment on Viking died with him.
It was generally seen as the best way to discover life on Mars, and including a Mars bar as food (along with sponsorship by M&M/Mars) would be the best way to get it to Mars. I wonder if ISRO would accept such "sponsorship", if they followup MOM with a lander, it might help with the budget and PR.
What a dumb idea.
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GEO stands for Geostationary Earth Orbit. It's a specific orbit, at ~36000 km, over the equator, where your orbital speed matches the Earth's rotation, and therefore the satellite remains over the same spot. This orbit is very popular with telecom and TV satellite operators who want permanent coverage of a particular country. The drawback of reaching this orbit is that it is very high, and therefore requires a lot of dV to get there, and it needs to be equatorial, which means that you need to launch from near the equator.
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2 hours ago, YNM said:
Give it more funds perhaps ?
I'm not sure that the problem with Russian space is due to funding. I think it's mostly a problem with workforce qualifications. Russia is suffering from a brain-drain, where skilled engineers and technicians tend to either flee Russia or go work in more lucrative businesses (gas and petrol for example). I suspect that a large part of the Russian space program is made of poorly qualified technicians, with a high turnover rate. Also, the fact that many of the materials and processes used are obsolete doesn't help.
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5 minutes ago, CatastrophicFailure said:
So clearly, after discussing all the options here, the only logical solution at this point is to wait until BFR is flying, and simply launch the crew a new space station.
I know you're joking, but I don't see BFR ever docking to the ISS. It is large and would put a lot of stress on the structure. It's probably too "dirty" too (thruster gas pollution). We also don't even know if there is a docking adapter in any of the recent designs. At any rate, it would have to go through years of certification with NASA before it would be certified for operating in vicinity of the ISS, at which point the ISS will be near its end-of-life.
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5 hours ago, Ultimate Steve said:
Okay, let's talk about implications... If Soyuz is not cleared for flight before December (or early January if we want to be a bit risky) then the fuel tanks of Soyuz MS-09 will be dangerously corroded by the fuel they carry and the crew will have to come home, which is not good for the station, as a lot of the crew's work is maintenance. Also this isn't as important but I think we'd all like to keep our streak of having someone in space at all times.
So we need to keep the station constantly manned. We have a few options. Generally the list becomes more impractical as you go further down, but that's a trend, not a rule.
1 - Just send Soyuz MS-11 according to schedule. Soyuz is really reliable. If the investigation is finished in time, or even if it's not fully concluded, the failure is probably a related to a manufacturing defect. Increasing inspections at the factory should be sufficient. Chances are that MS-11 will not fail. But the chance is there.
2 - Send Soyuz MS-11 on schedule but unmanned. If we're being really risk averse or the investigation takes too long, MS-09 will have exceeded its warranty and will need to be jettisoned. An unmanned MS-11 could serve as a return vehicle and a buffer until more crew could arrive, although the crew of MS-09 would be in for a really long mission. And it would cause more crew scheduling issues, notably a big wave for the crew lineup and pushing of the last American bought seats to later flights.
3 - Jettison MS-09 and wait with no escape ship. There has not been an incident on the ISS causing need for an evacuation. There have been a few close calls, though. Simply waiting for a spacecraft with return seats to arrive is an option, the chances that something catastrophic will happen are rather low. This also extends the MS-09 crew mission time. And also will make the officials wary.
4 - Jettison MS-09 and wait with CRS-16 as an escape ship. Wait for unmanned MS-11 to return the crew. Dragon 1 is a proven re-entry platform with 15 CRS re-entries and IIRC 2 test flight re-entries with no failures (but possibly some parachute anomalies). In the event that the crew need to go back while waiting for a proper return module, they could borrow CO2 scrubbers and oxygen replenishers from MS-09 if they can get them out and rig up some padding for use as seats. They might not even need extra oxygen if they can land quickly enough. But Dragon 1 was never intended for crew, this will again make the officials wary. If needed, instead of only being used as an emergency descent vehicle, CRS-16 could be the planned descent vehicle, but there is no way that would clear NASA review. If this does, then it could also be fitted with seats and scrubbers before launch.
5 - Jettison MS-09. Keep an escape ship on standby (Dragon 1), send MS-11 manned, return crew of MS-09 on MS-11, MS-11 on MS-12, and MS-12 on DM-2. Same idea as 4, but chaining the Soyuz return times until DM-2, with its up to 7 seats, would arrive with only 2 on board, providing ample return room. Same cons as 4. Dragon 2 will have been tested on DM-1 and the inflight abort so it will be proven by now.
6 - 4 but with DM-1 as an escape ship. Slightly better than 4, actually, as Dragon 2 was designed to carry crew, but will not have undergone a re-entry test.
7 - 5 but with DM-1 as the return ship. The daisy chaining of Soyuz descent flights could be ended earlier using DM-1 as the planned return pod. Same cons as 6.
8 - Fast-track commercial crew and launch a replacement crew on DM-2 or the second flight of Starliner. Very possible, Boeing was in talks for this before the launch failure even happened. Both Dragon and Starliner can seat 7 if need be. You'd have to get them up before 2019 (not happening) or else use an interim spacecraft as an emergency descent pod, like in option 4. It could be CRS-16 or DM-1. If the need extremely arises, the inflight abort could even be launched as DM-2. Boeing isn't doing an inflight abort, and SpaceX did a pad abort already, although that was ages ago.
9 - REALLY fast-track CC and launch a replacement crew on DM-1 or Starliner flight 1. Not happening. Legislation and common sense will not allow SpaceX or Boeing to fly crew on the first flight of an unproved vehicle.
10 - Vent propellant tanks on Soyuz MS-09 and refuel later. If the problem is corrosion and the spacecraft can last longer if it weren't for the fuel, either vent or burn all of the fuel (ISS hyper-reboost?) but keep it attached and refuel it later. I don't know if this is possible. It certainly wasn't designed for in-orbit refueling so I doubt this will be considered. But, if the Soyuz/Progress ports are androgynous then you could use another Soyuz or Progress to de-orbit MS-09.
11 - Ask China to launch a Shenzhou. I read that the docking ports on Shenzhou are similar to the APAS-89, which are similar to the APAS-95, which are similar to the IDA... I think. I could be wrong. If (very big if) the Chinese have a Shenzhou lying around, then the docking port might be able to be ripped out and replaced with an ISS compatible one, or even modified. An adapter could also be built, going Chinese port on Shenzhou -> Chinese port -> Adapter structure -> ISS compatible port -> ISS. But at this point I'm grasping at straws, and IIRC NASA is banned from collaborating with China. China would also need to be paid somehow. And Shenzhou can only carry 2.
12 - Launch Orion on a Delta-IV Heavy with crew to replenish ISS crew. REALLY not going to happen, but if aliens came and told us to do this or the world would be destroyed then we could pull it off... I know that the Orion for EM-1 is at least somewhat near to being done, but I don't know how close the next D-IVH is... And D-IVH is not man rated. But it has gone its whole life without a big failure and has carried Orion (albeit without a service module - a big deal, probably can't dock without one) before. The service module for EM-1 is in storage IIRC, and you could launch it with only a little bit of fuel as to not overwhelm D-IVH.
13 - Launch Orion on D-IVH with 1 or 0 crew. Same as the above but just as a return vehicle for the crew of MS-09.
14 - 12 but with Falcon Heavy. Advantages: the next FH is probably going to be ready before the next D-IVH. Disadvantages: FH is not man-rated (although F9 will be), FH has only flown once, and FH has not carried Orion, nor was it designed to.
15 - 13 but with Falcon Heavy. Self explanatory.
14 - Launch crew on CRS-16. Like the options for using CRS-16 as a return ship, except modifying it on the ground to add seats, basic ECLSS, and other basic amenities, many of which can probably be ripped from Dragon 2. It's better than crewing DM-1 because it's a proven platform, but worse than crewing DM-1 because it wasn't designed for this.
I think I covered most of the possible options... Almost none are actually practical, though given all the unwillingness to take risks (not necessarily a bad thing). I know more than half of these are utterly ridiculous, but thoughts?
Dragon 1 cannot unberth without someone on the station closing the hatch and controlling the arm, so any options involving Dragon 1 are a no go -
Any option involving leaving the crew without an evacuation vehicle (Soyuz) are a no go.
Any option involving a vehicle that is not yet ready to transport crew (Dragon 2, Starliner or Orion) or to operate in vicinity of the ISS (Shenzhou) is a no go.
The shelf life problem with MS-09 is not just about fuel, so #10 is a no go.
In your list, only #1 and #2 are options at this point. There are other opportunities that involve shuffling around the Progress launch that was scheduled for November.
However, resuming Soyuz launcher operations assumes that the investigation determines that the problem was a one off and is not systemic. Given the reliability issues that Russia has been having over the past years, I wouldn't be very confident with that sort of conclusion, and neither would NASA. And don't forget the concerns about hole in the MS-09 for which there still hasn't been a satisfactory explanation. Who knows if Soyuz is still safe at this point? What if there is another hole (or other manufacturing problem) on the next Soyuz ?
There seems to be a deep-rooted systemic problem with Russian quality control that has to be addressed, and that can take a lot of time.
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The docking modules were not originally part of the Shuttle design. They were built by Russia and retro-fitted as part of the Shuttle-Mir program. This is why the US segment of the ISS was fitted with Russian APAS docking ports.
Also, Columbia was never fitted with the docking equipment.
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Submarine-launched rockets don't use bouyancy to get out of the water. They use solid rockets. Those things are pretty heavy solid boosters.
Adding the structural reinforcements to make your rocket withstand underwater pressure, plus the complexity of the thing and all the additional failure modes would take away any benefit of extra delta-v if there was any (but there isn't).
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4 hours ago, Xd the great said:
Seriously, how does elon plan on making the bfr stable during launch? It has wings in the middle and cnards in front.
They are not wings, they are fins. Unlike something like DreamChaser, they do not generate lift, and since they are symmetric, they should be pretty much neutral.
The canards are also symmetrical and can be trimmed to be neutral. If anything, they should help stability. After all, fins on the front of a rocket are nothing new.
Now, vertically launching with a spaceplane on top (X-20 DynaSoar, DreamChaser, or Hermes) is much more problematic, because those vehicles are designed to generate lift on re-entry. You are going to need strong control authority to keep it flying straight.
That's why the Space Shuttle flew to orbit "upside down". It could use some of the lift generated by the wings to rotate the flight curve rather than fight the lift with the engine gimballing.
You just have to keep in mind that although it looks like it has wings, the BFS is not a spaceplane.
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10 hours ago, Rakaydos said:
It also implies there's a version where some number of the engines are obscured.
Or it implies that there might be a version of the rendering where some other number of engines is firing.
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1 hour ago, tater said:
I think they only need extend enough to cover small terrain changes. Think shock absorbers, not long, spindly legs.
It's not the length that bothers me, it's the surface area in contact with the ground. 100 tons per leg, on a surface of a few square centimeters, is bound to sink into the ground, even on a prepared surface. It needs feet or pads with a wider surface area.
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The petals look like they could be some sort of inflatable device. A ballute maybe ? Or a landing device ?
I'm having problems imagining telescopic landing stilts that extend out of the fins. Without feet or pads, the weight/surface area ratio is going to cause problems on unprepared terrain, and even prepared terrain. The whole ship could weigh several hundred tons and that entire weight will press on a total surface area of about 1 square meter.
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A meta-nozzle might not work as well as a proper vacuum nozzle, but it might be a good enough compromise to make the reduction of engines worthwhile.
Those petals might also be for protecting the engines from debris during landing.
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9 minutes ago, tater said:
You think they deploy to form a sort of meta-engine bell?
Speculation at this point, but that explains the lack of vacuum Raptors.
9 minutes ago, Ultimate Steve said:No problem, butt-to-butt is still doable, just roll a ship 180 degrees or so.
Not with the petal things in the way. I still think D2-like nose-to-nose docking is more flexible and provides more contingency options (evacuation, rescue, tug operation, access to ISS and other vehicles)
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This design makes much more sense than the 2016 and 2017 designs. I really couldn't see those doing any realistic re-entry and flip-over maneuvers, nor could I see fitting a landing gear wide enough for unprepared terrain, high enough to keep the engines safe, and strong enough to support the ship and cargo in 1G.
This version solves most of those problems. I'm pretty sure the lower fins fold upwards on re-entry, giving it a DreamChaser-like profile.
The petals could be for vacuum propulsion, but they could also be some sort of device to protect the engines during re-entry and landing.
One thing that this design breaks is the back to back refueling method. I suppose they could still have nose-to-nose docking, which actually provides more flexibility (ability to transfer crew, ability to fire the engines while docked...)
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ITAR has nothing to do with hitting planes. It's about exporting technology, and it's a US-only thing.
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1 hour ago, Cassel said:
But if you would leave this car in vacuum half of those things wouldn't happen?
Yes. Even faster actually.
Anything normal rubber or plastic will outgas and go bad nearly instantly. Unless you have active attitude control, your car will end up tumbling, which will cause thermal expansion and retraction cycles, which in turn will eventually cause material fatigue and leakage. Batteries will go flat regardless of the atmosphere.
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2 hours ago, MinimumSky5 said:
True, leave the car too long and it will have issues, same as anything, the point that I'm trying to make is the the systems in the Orion will not be taxed any more during a voyage to Mars than they would be during a voyage to low orbit.
No, but it has a shelf life like everything else. It will suffer wear and decay after several months, whether it's in orbit, en route to Mars, or in a warehouse at Cape Canaveral. It is designed to support long-duration deep space missions, with up to 21 days active crew time plus 6 months quiescent. That's it. Beyond that, you are outside of the manufacturer's warranty and if it breaks down, you're on your own to get a tow, but more importantly, those are the specs each individual material and component(tank, seal, filter, pipe, fluid, etc...) is designed for.
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5 hours ago, MinimumSky5 said:
But the ship won't just fall apart after a few years of flight, because most of the systems will be offline to preserve them, in case the crew need a backup. If the ship was so poorly built that failure over that time line was likely, then NASA would never launch it even to low earth orbit.
Cars are designed to be used almost daily, for commuting to work and back, but leave it sitting in your driveway for a month, and it will run just as well as if you'd used it the day before when you start it up. Space is basically the same, in low orbit, interplanetary space, or Martian orbit, so sending the ship out on a solo mission to Mars won't teach us anything, aside from a spectacular way to waste a billion dollars.
That is simply wrong. Leave your car in your driveway for a few months, then chances are when you start it up, the battery will be dead and the tires will need inflating. Leave it longer and you will probably need an oil change and AC will need recharging. Leave it longer and the gas will have gone bad, rubber pipes will have degraded, brake caliper seals will need changing, and so on...
1 hour ago, MinimumSky5 said:Vacuum conditions aren't that difficult to deal with, it just requires a good pressure vessel, and submarines have to deal with higher pressure differences routinely.
There is no such thing as "a good pressure vessel" over an infinite amount of time. Everything is porous down at the molecular level and materials do degrade.
NASA CLPS Program
in Science & Spaceflight
Posted
The only "profits" in the space sector so far, other than telecom satellites, is having NASA or the military pay for launches. In the end, it's always the taxpayer that foots the bill.