If you have a simple question on space or astronomy but don't want to play the Space trivia quiz then this thread is for you. There are quite a few very knowledgeable members on this site who will be more than willing to answer your question.

If your question is likely to need long and involved discussion then it would probably be best to start a new thread, if on the other hand, it can be answered with simple facts then feel free to post it here.

If your question is about the Apollo programme/missions then a recommend that you read through MID's excellent thread, The Apollo Program: The Moon Landings, I may have already been posted that. If not that may be a better place to ask it.

Thank you in advance for you participation and I hope you get the answers you want.

I'm all for this!

How is it that the space shuttle goes 17000 miles an hour up in space above the Earth without any serious side effects on the astronauts?
How come the shuttle doesn't zoom away from the astronauts when they spacewalk?
And what about space debris from lost sattelites.....etc..going super speeds...wouldn't that bombard the shuttle and spacewalkers ?

Actually they do get hit by space debris every now and then.NASA just discloses these type of incidents.As for the question of the shuttle not moving away from the astronauts,well it is kind of like sitting on the back of a moving vehicle if you trough an object into the air the object for a brief period travels just as fast as the vehicle but slows
down gradually because of friction with the air.Now that is not true when in space because there is no friction with any type of air or wind or whatever, so the astronauts travel the same speed as the shuttle and if you where to kick away from the shuttle,well that is just another problem altogether .

Speed does not have any effect on you (if it did we would be in big trouble, the Earth is rotating once a day, orbiting the sum once a year in a galaxy that is rotating and moving through the universe as the result of the big bang. Even sitting still you are travelling at thousands of miles an hour).

What does have an effect is acceleration. This is felt in terms of g force. The shuttle (and other manned spacecraft) keep acceleration low enough so that the astronauts do not suffer any ill effects. If you were to accelerate them more rapidly (firing them into orbit using a huge gun for example) then they would suffer or be killed as a result.

Think of it in this way, when you are in a car travelling at a constant speed then you feel no effect. Put yor foot down and accelerate and that is when you feel the kick in the pants. Same thing for the shuttle.

This is a result of Newton's First Law of motion, which states, "If no net force acts on a particle, then it is possible to select a set of reference frames, called inertial reference frames, observed from which the particle moves without any change in velocity." In otherwords there is no force acting on the shuttle or the astronauts (or you and the car) whilst they are travelling at a constant velocity.



Because they are orbiting the Earth at the same velocity as the shuttle. There is no force acting on the astronauts or the shuttle to accelerate or decelerate either of them (good old Newton again).


Space is big. The amount of debris is low enough that the chances of a collision are small. Large objects such as lost satellites are easily tracked from Earth and the shuttle (or the ISS) can take avoiding manouvers. If a piece a large enough piece of debris were to hit the shuttle then it could cause serious damage. A spacewalking astronaut is especially vulnerable, but the odds of being hit are acceptably low.

It is possible that at some time in the future debris could be come a significant threat. There is the possibility that something called the cascade effect could happen. If the concentration of debris becomes high enough then the chances of an impact with large satellite becomes higher. Every time a large satellite is hit and destroyed it breaks up into dozens, even hundreds of pieces of debris. This in turn increases the chances of impacts with other large satellites, increasing the number of collisions and therefore the amount of debris and so on. This would make low Earth orbit a no go area. However as scientists and satellite operators are becoming more aware of this possibility they are doing more to ensure it doesn't happen. Old sateelites are now frequently deorbited or placed into a "graveyard" orbit where they wont cause problems. Upper rocket stages are also now frequently deorbited or, at the very least, designed so that the fuel in them doesn't explode at a future date, an occurrence that used to be common as corrosive fuel ate its way through fuel lines.

I hope this has been of some help.

Those are reasonable questions!

Let's try this:

Because the astronauts are also going 17000 miles per hour.
Think about this...


When you're traveling along the highway, or in a train, or even in a plane, at 60, 100, or 500 miles per hour...do you ever have any ill effects from traveling along at those speeds?

No. Because you're traveling along with it, at a relative velocity of 0. You're sitting still relative to your vehicle.




Same answer.
Because the shuttle, and the ISS, or the HST, and the astronauts are all moving along at the same speed.
Stepping out of the confines of the Shuttle, or whatever spacecraft, is not like stepping out of an airplane at 33,000 feet. There's no atmosphere up there which your body would react to via drag. You're as much a spaceship as the spaceship! You're moving along at the same speed, and relatively speaking, it's 0.

If you flop out the door of an airplane flying along in the atmosphere, you'll be waving bye bye to the plane as you decellerate in the air...in space, you keep moving along with the spacecraft.




Odds are very, very slim.

There are plenty of pices of debris floating around on orbit, certainly. We are currently tracking thousands of them. But orbit is a very large place. The odds of a collission are exceedingly slim. Further, most of the debris is on orbit in the same relative direction and at similar velocities to the Shuttle or ISS. Thus, convergence possibilities are further reduced, and most things are moving right along with the spacecraft


There is of course a slim possibility of an orbiting piece of debris intersecting the inclination of a Shuttle orbit from an different inclination, which indeed could potentially create catastrophic results if the intersecting piece was large enough (we've been hit by debris already on several flights....but very small, insignificant pieces which have created "dings" at worse). But everything on orbit is moving at the same speed at any given altitude, and generaly from west to east.

If we're at 200 miles altitude, there's no debris moving any faster than we are at that altitude. Anything at our orbital inclination has little chance of intersecting us...and if it does, we might get a ding depending on th angle of incidence and the size of the particle. However, if something fairly significant at say 30 degrees inclination and at the same altitude is approaching and happens to intersect a Shuttle, or the ISS, at its 51 degree inclination...a very, very remote possibility, mind you, it's possible to have a damaging collision at 6000 miles per hour relative speed. Not a good day.

However, most equatorial debris is at lower, or higher altitudes than that of the typical Shuttle/ISS orbit (which is at a polar inclination). Thus, it's not in the vicinity and is moving faster (in the lower altiutude case), or slower (in the higher altitude scenario) than the Shuttle or ISS are at. Most of the debris at typical Shuttle/.ISS inclinations was created by the Shuttle and ISS, so it's moving along at the same relative speed. Anything that was accelerated from that location is actually in lower orbits, and anything retrograde may have re-entered the atmosphere, or moved into a higher orbit as well.

Basically, while the possibility is present, it's very remote...rather like getting struck by lightning, or being sucked up by a tornado...in fact the odds of either one of those occurrances, while slim, are probably greater than a significant orbital debris collision.

Are such minor incidents not mentioned on the news like a rip in the solar shield? I guess the damage has to be great enough to report on the news.




I had to read that a few times to understand it but i got it now. Thanks for the answers. That's stuff i had always wanted to know about space.

Thanks for answering this...along with waspie Dwarfs explanation i have a clear understanding of this now.

The key word is minor. We are talking about small pits in windows and in the heat shield tiles which are absolutely no threat to the shuttle or the crew. In one case such a pit in an outer layer of one of the windoes was caused by a collision with a fleck of paint. These minor incidents are not even noticed until after the orbiter is inspected after it has returned to Earth.

I will explain by what I mean by (incidents not mentioned).It is simple really NASA just don't want the public to panic and give them second thoughts about the space-station .

You're welcome Ghost!

...well, second thoughts about the ISS aren't going to really affect anything. That baby's there to stay!


To be truthful, though, there's some sense of fact in what you relate, although it's a very small aspect. I think avoiding public panic, or more appropriately public misunderstanding and over-inflation of the insignificant is much less pronounced that perhaps in the past. Today, NASA tends to reveal damned near everything, even those things that would only be of interest to the engineering community, and they sometimes go to very lengthy extents to explain the technical in terms that the press corps can understand.

We did recently discuss a small ding in a window. I looked at it and knew it was a non-mission impact, and particularly common thing, but they went to great lengths to illustrate it, and explain it to the press ad-nauseam. I have to commend today's NASA on communications...even something like this window ding...despite the fact that you'd need a 20 mm round to penetrate one of those windows (the one in question was a multi-paned 2 1/2 inch thick window)!

Hello Waspie.

This is just a question nothing more.I kind of lost track of the amount of modules there is on the ISS at this time.The reason Im asking this is when I was on the road at night
I saw a big object moving fast across the sky Bright shine at first then after a while it became a dim light like a satellite far above earth orbit and I thought to myself I must have seen the reflection of the ISS solar panels.I am asking this because I am heavily interested in the ISS and the SpaceShuttel.

By my calculations currently (including the two airlocks and the nodes) there are 9 modules on the ISS: Zarya, Unity, Zvezda, Destiny, Pirs, Harmony, Columbus and the Japanese Experiment Logistics Module.

It is quite possible that you saw the ISS. NASA have a page which calculates when the ISS will be visible from you location. You can find it HERE.

Thanks, that is all I needed to know.