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I am curious as to how fast we can get something to move. (aka a spacecraft - not something like "fricken lasers" [even those attached to sharks]). I am wondering how long it would take a fast spacecraft to travel to one of the outer planets, and the speed it would likely be travelling(presuming we launched at a time when the earth and outer planet were on the same side of the sun...).
Are our spacecraft moving at even a percentage of the speed of light?
Established Member
It all depends on how big of an object you want to accelerate. In particle accelerators, we get subatomic particles up to significant fractions of the speed of light. As far as objects big enough to feel/touch, the fastest I am aware of were the Helios probes, which made extremely close passes to the sun, and reached speeds upwards of 150,000 mph (roughly 250,000 kph).
However, you question relates to missions to the outer Solar System, where the extreme Solar gravitational forces that accelerated the Helios probes are not available. The best example of a high-speed outbound probe is New Horizons, which is currently traveling at a velocity of about 54,000 mph (24 km/s) with respect to the Sun. Its speed will vary on its trip to the outer Solar system, but it will take roughly 10 years to reach Pluto.
With larger rockets and/or a more ideal planetary alignment for multiple gravitational assists, it would be theoretically possible to make that trip faster, but not by more than a couple of years.
Regardless, you will never see planetary probes or inter-planetary spacecraft within the Solar system travelling much faster than this simply because of the extreme amounts of energy required to slow back down when you reach your destination. If a probe passed Pluto at any significant fraction of the speed of light, you would have very little time to collect any data. As it is, at the speed of New Horizons, the project scientists are going to really have to hustle during the few months when New Horizons is close enough to the Pluto system to get good pictures/measurements.
Established Member
However, probes that have been launched toward the sun have reached speeds above 500,000 kmph.
Order of Kilopi
Here's a somewhat related topic:
http://www.bautforum.com/showthread.php?t=40282
Keep in mind that the "fastest man made object" has little relevance to the issue of getting spacecraft to a destination quickly. That depends on feasible propulsion technologies and economics.
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The Leif Ericson Cruiser
Order of Kilopi
Probes are not (usually) launched when the two planets are on the same side of the Sun. Or, at least, that is not the relevent factor. Probes are launched when the trip is most economical. For example, Mars probes are launched when Mars is on the opposite side of the Sun from Earth, because by the time a probe on the most economical orbit gets to the orbit of Mars, Mars will be at that point in its orbit....presuming we launched at a time when the earth and outer planet were on the same side of the sun...
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Thanks for the link. Looks like the other post was virtually identical (guess great minds think alike (although I am only running a 'great mind' emulation program until I get my upgrades...))
So I guess that if it takes a probe 10 years to reach Pluto, and Pluto is about 39.5 AU away, and the nearest star is 272,061 AU; at our present technological level it would take 6887 years or so for us to get a probe to another star system to check out their planets up close. Guess I'll have to put off my plans for intergalactic conquest for a couple of millenia. Sigh.
Kaptain K. - thanks for reminding me about trajectory. You would think an old tanker would remember that you have to lead a moving target.
Anyway, I appreciate your thoughtful responses.
Established Member
We could probably work out something a little faster if we are talking interstellar distances. Some sort of nuclear drive could get speeds significantly faster. Other possibilities are ion drives and solar sails. However, we are still talking time scales on the order of multiple centuries to the nearest stars. We need some incredible technological breakthroughs to bring an interstellar trip down to something a single generation of humans could see to the end.
Also, remember that the faster we get there, the harder it will be to slow down when we arrive.
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http://www.bautforum.com/showthread.php?t=37223&page=4
in this link it says that Voyager is faster- travelling at 17 km/s where as NH will only be travelling at 13 km/s (due to fewer gas-giant gravity assists) when each reaches 100 AU.
I know the heliocentric speed quoted below (above?) is 24 km/s: is the discrepancy due to the craft's slowing down as it travels? Is there another explanation?
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It is currently traveling at 24 kms. As it climbs out of the Sun's gravity well, it will slow down. It will get a boost when it is near Jupiter, but then start slowing again.
Order of Kilopi
Voyager is doing quite well for current technology. Given enough money, one way to do a bit better would be a powered gravity assist around the sun. You would send a probe on an upper stage to make a close approach to the sun, then fire the booster at perihelion (closest approach). Of course, it would go past whatever target it is sent to more quickly.Originally Posted by DyerWolf
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Established Member
500,000 kilometers per hour is 139 kilometers per second. Can any one confirm that as a peak speed during a near miss of the sun?
Even if we can average 100,000 miles per hour to Centrii, (24 trillion miles) = 240 million hours = 10 million days = 27,379 years travel time. Actually it is about 4% farther to the three stars in the Centarri system. How far away will they be in 28,000 years due to proper motion?
If we are going to Centarii, we should likely state our speed relative to Centarii, not relatve to the sun = 24 kilometers per second plus an amount added vectoraly. Neil
Established Member
The Helios I and Helios II space probes did indeed set the speed record, but the speed was "only" about 250,000 km/hr, about half what isw stated above.
http://en.wikipedia.org/wiki/Helios_probes
Newbie
A: In fact the fastest space shuttle's built, fly (in space) at speeds of 150,000+ mph...light in-fact travells at around 6,000,000,000+ mph...in answer of your question, man made spacecraft travel at speeds far from that of light!x x x
Newbie
A: In fact the fastest space shuttle's built, fly (in space) at speeds of 150,000+ mph...light in-fact travells at around 6,000,000,000+ mph...in answer of your question, man made spacecraft travel at speeds far from that of light! x x x
Order of Kilopi
Since orbital speed is around 18,000 MPH (relative to the Earth), when did the shuttle do 150,000 MPH? And relative to what?A: In fact the fastest space shuttle's built, fly (in space) at speeds of 150,000+ mph...light in-fact travells at around 6,000,000,000+ mph...in answer of your question, man made spacecraft travel at speeds far from that of light!
Order of Kilopi
Welcome to BAUT, hillbilly.A: In fact the fastest space shuttle's built, fly (in space) at speeds of 150,000+ mph...light in-fact travells at around 6,000,000,000+ mph...in answer of your question, man made spacecraft travel at speeds far from that of light!
A couple of points. The speed of light in a vacuum is about 670,616,629 miles per hour. The space shuttle can move at roughly 18,000 mph in orbit around Earth.
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Newbie
A: I have read before than on a shuttle launch they tested what the speeds an apollo rocket couild perform. I unfortunately have forgotten what excact apollo rocket was tested. It managed to reach speeds (not in orbit to earth) of 150,000+ mph!
Established Member
We have the technology and knowhow to build a near lightspeed ship.... but we will never have the money.
Order of Kilopi
What technology are you referring to?
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Order of Kilopi
There were the Helios probes (not Apollo):
http://en.wikipedia.org/wiki/Helios_probes
There were two in the series, Helios I and Helios II. They were launched to orbit and measure the Sun. They set a speed record for spacecraft at 252,792 km/h (70.2 km/s). They also set the record for closest approach to the Sun, at about 45 million kilometres, slightly inside the orbit of Mercury.
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Order of Kilopi
It's incorrect then.
The fastest Apollo rocket (not the shuttle) was the Saturn V, which took the capsules up to about 11km/s, or about 24,000mph.
Established Member
A related question is which spacecraft obtained the fastest speed not including gravity assist maneuvers. In other words, which spacecraft had and used the highest self-provided delta V. New Horizons perhaps?
Established Member
Yes, New Horizons had the fastest launch speed of anything from Earth.
Order of Kilopi
That is a strong possibility for most total spacecraft provided delta v. What was the total delta v on Deep Space 1?
Banned
Slow down a bit... I am not keeping up. You are throwing numbers at me that I do not understand. I am easily confused,
I understand 11km/s. as the velocity required to leave Earth. I understand re-entry speeds are over this as gravity assist accelerates the craft. I follow the solar near approach would gain from that masses gravity. So could one of you please just make a list.
Established Member
Bad news.
Established Member
In Carl Sagan's series COSMOS he showed schematics for a proposed nuclear powered ship that would go near lightspeed. (This was in the 80's)
He said (and explained how) that it could actually be built NOW (then), and it would really work, but the sheer size, and cost would prohibit it from ever happening.
And it would have to be built in space.
The question wasI am curious as to how fast we can get something to move.
Order of Kilopi
I don't recall him saying that, but if he did, he was wrong. Even a multistage fusion rocket that we couldn't possibly build today would be lucky to manage 10-20% of light speed. The only extreme nuclear concept that might be possible today is fission/fusion based Orion, but even that is questionable, and 1% of light would be extremely impressive with that technology.
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Established Member
I don't think the space shuttle has ever gone more than 30,000 miles per hour with respect to Earth's surface. According to another thread the New Horizons space probe went (will go?) several times that fast including several gravity assist manuvers. Travel in space at a thousandth of the speed of light or faster is largely untested, but we will likely have an ion engine (or something similar) reach one percent of the speed of light within the next 20 years.
With a significant pay load, such as a human; we may never reach 1% of c. Neil
Order of Kilopi
What about things somewhat bigger than atomic nuclei, but smaller than spacecraft? And not launched into space, but shot from guns, of some kind or another, right here on Earth (although perhaps in a chamber pumped pretty much free of air)?
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