5 ms·

We don't have any spacecraft that can go that fast, do we?

by jdormit 10y ago

JorgeGT 10y ago
No. If I'm not mistaken we're in the order of magnitude of 0.0001c.
dexwiz 10y ago
No, but we probably could with enough fuel. The bigger issue is space dust. Hitting it at relativistic speeds would be like flying into a cosmic shotgun for the entire journey.
- deleted 10y ago
  [deleted]
- aaronblohowiak 10y ago
  Could that cause accidental fusion?
  - delecti 10y ago
    Assuming this [1] is reasonably accurate, very much yes. It proposes fusion occurring at speeds as "slow" as 0.9c. [1] https://what-if.xkcd.com/1/ https://what-if.xkcd.com/1/
- deleted 10y ago
  [deleted]
- snerbles 10y ago
  A large mass of water ice would make a decent ablative shield.
- CoolGuySteve 10y ago
  According to this paper, you can travel around 0.5 c before the radiation caused by colliding with interstellar hydrogen kills you: http://www.scirp.org/journal/PaperInformation.aspx?paperID=23913 http://www.scirp.org/journal/PaperInformation.aspx?paperID=2... "Going slow to avoid severe H irradiation sets an upper speed limit of v ~ 0.5 c. This velocity only gives a time dilation factor of about 15%, which would not substantially assist galaxy-scale voyages. Diffuse interstellar H atoms are the ultimate cosmic space mines and represent a formidable obstacle to interstellar travel."
  - gech 10y ago
    Couldn't you put some kind of "snowplow" on the front so it pushes the oncoming detritus away to the sides?
    - temuze 10y ago
      A reddit thread mentions that idea: https://www.reddit.com/r/science/comments/12nls5/speed_kills_highly_relativistic_spaceflight_would/ https://www.reddit.com/r/science/comments/12nls5/speed_kills...
pshposh 10y ago
I've read about laser systems for sending unmanned crafts at high speed: http://www.space.com/29950-lasers-power-tiny-interstellar-spacecraft.html http://www.space.com/29950-lasers-power-tiny-interstellar-sp...
deleted 10y ago
[deleted]
josho 10y ago
If I understand our capabilities correctly we can't even escape the solar system without using gravity assist boosts from other planets, let alone sustaining thrust for a long period. http://solarsystem.nasa.gov/basics/chapter4-1 http://solarsystem.nasa.gov/basics/chapter4-1
- deleted 10y ago
  [deleted]
- narag 10y ago
  "Capabilities" seems a little ambiguous to me. Is it what we have done or what we could do? Using those boosts is a way to achieve the same results, only cheaper. Yes, it's slower than building a big ass rocket, but it seems people that sign the checks are in no hurry. Also if I'm not mistaken, Voyager probes were not even intended to live so long or leave the system. If there were a reason to send a probe to another star as soon as possible and no matter the cost, there would be a way, maybe not fast, maybe very expensive, maybe something weird, but it would be done.
aaronblohowiak 10y ago
I think we do if you look at it in terms of acceleration. As I understand it, In space there is almost 0 friction so "fast" is more about acceleration than "top speed". In this view, 1g isn't that fast.
- xigency 10y ago
  About as "fast" as a helicopter at a stable altitude, or to fit with the no-atmosphere bit, a stationary jetpack or lunar lander (on Earth).
- wallace_f 10y ago
  Doesn't energy required to accelerate keep exponentially increasing, though? ke = mv^2
  - aaronblohowiak 10y ago
    Energy is relative to a frame of reference, and IIUC 1g acceleration of the space vessel is in The vessel's frame of reference, not earth's.

We don't have any spacecraft that can go that fast, do we?

by jdormit 10y ago

We don't have any spacecraft that can go that fast, do we?

JorgeGT 10y ago

No. If I'm not mistaken we're in the order of magnitude of 0.0001c.

dexwiz 10y ago

No, but we probably could with enough fuel. The bigger issue is space dust. Hitting it at relativistic speeds would be like flying into a cosmic shotgun for the entire journey.

deleted 10y ago
[deleted]
aaronblohowiak 10y ago
Could that cause accidental fusion?
- delecti 10y ago
  Assuming this [1] is reasonably accurate, very much yes. It proposes fusion occurring at speeds as "slow" as 0.9c. [1] https://what-if.xkcd.com/1/ https://what-if.xkcd.com/1/
deleted 10y ago
[deleted]
snerbles 10y ago
A large mass of water ice would make a decent ablative shield.
CoolGuySteve 10y ago
According to this paper, you can travel around 0.5 c before the radiation caused by colliding with interstellar hydrogen kills you: http://www.scirp.org/journal/PaperInformation.aspx?paperID=23913 http://www.scirp.org/journal/PaperInformation.aspx?paperID=2... "Going slow to avoid severe H irradiation sets an upper speed limit of v ~ 0.5 c. This velocity only gives a time dilation factor of about 15%, which would not substantially assist galaxy-scale voyages. Diffuse interstellar H atoms are the ultimate cosmic space mines and represent a formidable obstacle to interstellar travel."
- gech 10y ago
  Couldn't you put some kind of "snowplow" on the front so it pushes the oncoming detritus away to the sides?
  - temuze 10y ago
    A reddit thread mentions that idea: https://www.reddit.com/r/science/comments/12nls5/speed_kills_highly_relativistic_spaceflight_would/ https://www.reddit.com/r/science/comments/12nls5/speed_kills...

pshposh 10y ago

I've read about laser systems for sending unmanned crafts at high speed: http://www.space.com/29950-lasers-power-tiny-interstellar-spacecraft.html http://www.space.com/29950-lasers-power-tiny-interstellar-sp...

deleted 10y ago

[deleted]

josho 10y ago

If I understand our capabilities correctly we can't even escape the solar system without using gravity assist boosts from other planets, let alone sustaining thrust for a long period. http://solarsystem.nasa.gov/basics/chapter4-1 http://solarsystem.nasa.gov/basics/chapter4-1

deleted 10y ago
[deleted]
narag 10y ago
"Capabilities" seems a little ambiguous to me. Is it what we have done or what we could do? Using those boosts is a way to achieve the same results, only cheaper. Yes, it's slower than building a big ass rocket, but it seems people that sign the checks are in no hurry. Also if I'm not mistaken, Voyager probes were not even intended to live so long or leave the system. If there were a reason to send a probe to another star as soon as possible and no matter the cost, there would be a way, maybe not fast, maybe very expensive, maybe something weird, but it would be done.

aaronblohowiak 10y ago

I think we do if you look at it in terms of acceleration. As I understand it, In space there is almost 0 friction so "fast" is more about acceleration than "top speed". In this view, 1g isn't that fast.

xigency 10y ago
About as "fast" as a helicopter at a stable altitude, or to fit with the no-atmosphere bit, a stationary jetpack or lunar lander (on Earth).
wallace_f 10y ago
Doesn't energy required to accelerate keep exponentially increasing, though? ke = mv^2
- aaronblohowiak 10y ago
  Energy is relative to a frame of reference, and IIUC 1g acceleration of the space vessel is in The vessel's frame of reference, not earth's.