Russia and the ISS
Discussion
Simpo Two said:
there must be SOME mid-point at which there is enough atmosphere to grab/open something and so limit acceleration and the resultant crisping tendencies.
If there was such a point then I am sure those who design re-entry systems would have exploited it years ago. As they haven't, I reckon there isn't.CrutyRammers said:
I don't think it can slow you down enough though, before the air gets dense enough that crisping occurs.
Or ripping to shreds.The slowing down is provided by the vehicle itself - and they are designed and shaped in such a way that the correct rate of deceleration occurs.
Apart from ensuring that the heat loads are kept within the region where the spacecraft doesn't melt or the occupants are fried, the deceleration has to be kept low enough to ensure the occupants aren't squashed either.
It's all about maintaining a safe balance of forces as the craft slows from 17,500 mph down to around 400 mph in the space of around 15 minutes.
Once below 400 mph, aerodynamic devices such as parachutes can then be used to carry out a gentle landing.
Simpo Two said:
Somewhere between (a) completely weightless in a vauuum (where you can't deploy a chute because it will do nothing), and (b) plunging earthwards at 400+mph (when you can't deploy a chute because it will be ripped off), there must be SOME mid-point at which there is enough atmosphere to grab/open something and so limit acceleration and the resultant crisping tendencies.
You're not jumping from a stationary platform and gaining speed as you fall. Rather, you're already doing 17,000mph relative to the Earth when you push off from the space station and you need to decelerate in order to reduce your altitude so you can head-butt the atmosphere and slow down enough to safely open a parachute. http://what-if.xkcd.com/58/
BonzoG said:
You're not jumping from a stationary platform and gaining speed as you fall. Rather, you're already doing 17,000mph relative to the Earth when you push off from the space station and you need to decelerate in order to reduce your altitude so you can head-butt the atmosphere and slow down enough to safely open a parachute.
http://what-if.xkcd.com/58/
That was the question i forgot to ask the representative at Farnborough. How does the astronaut slow their own personal velocity down AFTER they abandon the crippled spacecraft to allow them to change their orbit so they intersect the upper reaches of the atmosphere and begin re-entry?http://what-if.xkcd.com/58/
BonzoG said:
You're not jumping from a stationary platform and gaining speed as you fall. Rather, you're already doing 17,000mph relative to the Earth when you push off from the space station and you need to decelerate in order to reduce your altitude so you can head-butt the atmosphere and slow down enough to safely open a parachute.
Yes but there is no drag as no atmosphere. Drag and friction is the problem not speed per se; after all it is quite safe to travel at 17,00mph in a vacuum. Eventually the atmosphere and drag will start, you're just going sideways (well top of semi-parabola) not down.If an astronaut had to abandon an orbiting spacecraft in some sort of an escape pod or escape module, in order to re-enter the atmosphere and return to earth, the escape pod needs to have some sort of rockets attached so that it can reduce its orbital velocity so that it starts the re-entry process.
Of course, if nothing is done, the module might re-enter the atmosphere on its own accord due to orbital decay. The problem is that can take days, weeks or even months for this to happen, and by then, the astronaut occupant would have long depleted their oxygen supply.
For a one man escape module to safely return an astronaut to earth, it needs to be able to start the re-entry process within minutes of leaving the stricken spacecraft.
Of course, if nothing is done, the module might re-enter the atmosphere on its own accord due to orbital decay. The problem is that can take days, weeks or even months for this to happen, and by then, the astronaut occupant would have long depleted their oxygen supply.
For a one man escape module to safely return an astronaut to earth, it needs to be able to start the re-entry process within minutes of leaving the stricken spacecraft.
More trouble for the Russians http://spaceflightnow.com/news/n1405/15proton/#.U3...
Eric Mc said:
For a one man escape module to safely return an astronaut to earth, it needs to be able to start the re-entry process within minutes of leaving the stricken spacecraft.
Indeed, I had it in mind that he would give the capsule a good shove off with his feet... though if that would be insufficient of course then the idea stops there.Where's Jeb Corliss when you need him?
The Shuttle's de-orbit burn knocked a couple of hundred miles an hour of the 17,500 mph orbital velocity. This changed the angle of the orbit slightly which allowed the Shuttle to dip into the upper atmosphere. Atmospheric drag did the rest.
For an astronaut to start entering the upper atmosphere, he too would need to decelerate by around 200-300 mph.
For an astronaut to start entering the upper atmosphere, he too would need to decelerate by around 200-300 mph.
While in other news....
http://rt.com/news/157800-russia-moon-colonization...
Could this be the start of another space race, but this time with three contestants ( Russia, US, and China ) ?
http://rt.com/news/157800-russia-moon-colonization...
Could this be the start of another space race, but this time with three contestants ( Russia, US, and China ) ?
t load of money thrown at the project.They already have two spacecraft that are heading towards manned operations - Dragon and Orion. If it was considered a national emergency, both could be carrying men within two years.
My hunch is that NOTHING related to manned spaceflight has any priority with the current administration.
My hunch is that NOTHING related to manned spaceflight has any priority with the current administration.
Eric Mc said:
They already have two spacecraft that are heading towards manned operations - Dragon and Orion. If it was considered a national emergency, both could be carrying men within two years.
My hunch is that NOTHING related to manned spaceflight has any priority with the current administration.
Orion may be ready in 2 years, but it doesn't have a man-rated launcher available, nor is there any work on providing one other than SLS which is at least 4 years from 1st flight. Both Dragon and its Falcon 9 launcher are actively being developed for man-rating so could be available sooner if the Russians cut off all access to the ISS for the US.My hunch is that NOTHING related to manned spaceflight has any priority with the current administration.
Agreed - Dragon would be the best option for an emergency programme to retain ongoing access to the ISS -if the Russians pulled the plug (which I actually doubt they will).
It all depends on how desperate the situation gets. When John Glenn flew on the Atlas back in 1962, by modern standards, the Atlas was by no means man rated.
It all depends on how desperate the situation gets. When John Glenn flew on the Atlas back in 1962, by modern standards, the Atlas was by no means man rated.
Eric Mc said:
It all depends on how desperate the situation gets. When John Glenn flew on the Atlas back in 1962, by modern standards, the Atlas was by no means man rated.
True - if they were willing to accept a similar risk level now they could probably fly astronauts in the next DragonGassing Station | Science! | Top of Page | What's New | My Stuff