StyroCupMan writes "NASA has announced that it will launch a satellite to map our solar system's boundary. It will also study the particles and radiation that pose a health and safety hazard to humans. Time to invest in that shiny new spacesuit."
The birth of interstellar exploration
by
It+doesn't+come+easy
·
· Score: 3, Interesting
Pretty cool. We are about to transition into the age of interstellar exploration, at least technically speaking, once the Voyager 1 probe "officially" cross into interstellar space. The actual boundary shifts in relation to the activity of the sun and so this new satellite should help determine (among other things) when Voyager has crossed over.
Interesting note: The Pioneer/Voyager probes illustrate the space exploration concept that the later you leave, the sooner you get there...
-- The NSA: The only part of the US government that actually listens.
Historically speaking...
by
anactofgod
·
· Score: 3, Insightful
This "surveying" of boundaries by my government has traditionally been the first step in the staking of claims and the erection of fences and walls. When does the landgrab start? I want to plan my flag on a choice piece of real-estate. *g*
So, I have a question. Why is it that when scientists talk about exploring the edges of the solar system, they insist in sending probes "out past Pluto"? On the one hand, I understand why we do so - our solar system does lie (primarily) in a plane, so it's natural to think that way.
But I argue it'd be easier to explore phenomina at the edges of our solar system by going in the third dimension - orthogonal to the plane of the solar system. After all, the Sun isn't just radiating in a 2-d plane. Or am I wrong in my assumption about how solar winds radiate?
Any scientifically sound reason why this is a bad idea?
Or are we doomed to continue think as Khan did/does/will? *grynn*
--
---anactofgod---
"Equal opportunity swindling - *that* is the true test of a sustainable democracy."
Re:Historically speaking...
by
iainl
·
· Score: 4, Interesting
The problem, if memory serves, is that it's a lot easier to sling a probe out along the plane than it is to send it "up or down" with any speed - simply because it's being launched from Earth any probe will already have a substantial amount of momentum in the plane.
-- "I Know You Are But What Am I?"
Re:Historically speaking...
by
CrimsonAvenger
·
· Score: 4, Informative
Any scientifically sound reason why this is a bad idea?
DeltaV required to head out perpendicular to the plane of the ecliptic is quite a bit higher than to go out along the ecliptic.
Achieving Solar escape speed from LEO in the plane of the ecliptic is ~9Km/s.
Perpendicular to the ecliptic, deltaV required is ~26Km/s.
And it's tough to use planetary slingshots when you're going out perpendicular to the ecliptic.
--
"I do not agree with what you say, but I will defend to the death your right to say it"
9 km/s is the static speed you must be moving if you stop applying thrust. In other words, when you stop applying thrust, you'd better be going 9 km/s or faster or the Earth will eventually pull you back.
Your example of moving up 1 inch per day (do you work for NASA, mixing measurement systems like that, now really!) implies that you continue to accellerate enough to maintain your position (i.e. you do not allow yourself to fall back that one inch) until you move up further.
-- The NSA: The only part of the US government that actually listens.
Re:Historically speaking...
by
mopomi
·
· Score: 4, Informative
Basically, an object needs a specific amount of energy to escape the gravitational well of some other object. Remember that kinetic energy is KE = 1/2 mv^2,
where m is mass and v is velocity.
Gravitational binding energy is the energy required to escape a gravity well (basically):
GE = GmM/R,
where G is the gravitational constant, m is the mass of the escaping object, M is the mass of the planet, and R is the planet's radius.
Setting KE=GE and solving for velocity gives you the escape velocity (the very minimum INITIAL velocity required to escape with NO ADDITIONAL ACCELERATION). Notice that the object's mass cancels, so you're left with a constant value for the planet's escape velocity (of course, you need more energy to accelerate a more massive object to the same velocity). Earth's escape velocity is actually 11.1 km/s. Not sure where that 9 km/s comes from.
Re:Historically speaking...
by
CrimsonAvenger
·
· Score: 4, Insightful
Earth's escape velocity is actually 11.1 km/s. Not sure where that 9 km/s comes from.
Read carefully. That was deltaV required to go from LEO (Low Earth Orbit) to Solar escape speed.
It assumes a starting speed of ~8Km/s (Actually, the orbit I assumed had ~7650m/s orbital speed), and a single burn in the direction of both the orbit around the Earth and the Earth's orbit around the Sun. It further assumed Solar escape speed was 42.1Km/s, which is true for a couple points along Earth's orbit, but I'm not sure exactly where, so I won't tell you the dates required for the burn.
If you add 9Km/s to your speed under those conditions, then you will find yourself moving along smartly in the plane of the ecliptic at just over 5250m/s relative to the Sun at some point in the indefinite future, when you are some arbitrarily large distance from the Sun (on the order of two light-months out, give or take a couple light-weeks)
--
"I do not agree with what you say, but I will defend to the death your right to say it"
Why do we need this? Someone please explain it to me. None of the Pioneer or Voyager probes have yet to reach the heliopause and they were launched in the 1970s. So we should expect to see results in sixty years? How about doing some USEFUL exploring like investigating Pluto/Charon and KBOs?
-- "Well Ranger Brad, I'm a scientist. I don't believe in anything." - Dr. Roger Fleming
How much will this cost?
by
VoxVeritas
·
· Score: 4, Insightful
I think this is a good idea. I just wish that they would save Hubble. They way they are dealing with Hubble is like junking your car just because it needs a new battery.
Hmmm... my girlfriend tried that logic too...
Re:Long-term science
by
jnik
·
· Score: 4, Informative
Nobody said the probe is actually crossing the termination shock. It's observing ENA's generated at the termination shock.
Uber-brief introduction to energetic neutral atoms: Ions (charged particles) are susceptible to magnetic and electric forces. As a result, they can be boosted to very high energies in certain situations, but also usually can't travel very far before being modified in some way by electromagnetic forces. If, however, an ion interacts with a neutral (charge exchange), it can "steal" one or more electrons from the neutral without substantially changing the energies of either, leaving a nonenergetic ion and an energetic neutral, which then leaves the vicinity as it is no longer subject to EM forces. We can observe these ENA's and infer properties of the acceleration region.
You don't exactly, but it's the only sensible way
by
Julian+Morrison
·
· Score: 3, Insightful
Escape velocity is for a ballistic trajectory. Ballistic, meaning unpowered after the launch. That is, if you chuck a rock at sea level upwards at that speed, it will slow and slow but never quite stop.
What you're talking about is escaping by just continually going upward, like climbing a ladder. Which you could, if there were a big enough ladder - but of course there isn't. So rather than standing on a solid, you have to continuously accelerate against gravity to even stay put. Possible - it's what a Harrier jump jet does when hovering at take-off - but expensive in fuel, meaning you can't do it long enough to get anywhere useful before the fuel runs out. It makes more sense to burn all your fuel as early as possible, accelerate as fast as possible, and coast most of the way ballistically. That way you get rid of the fuel fast (it's heavy and expensive to lug) and you don't waste effort just staying put.
Slashdot Mirror
Interesting note: The Pioneer/Voyager probes illustrate the space exploration concept that the later you leave, the sooner you get there...
The NSA: The only part of the US government that actually listens.
This "surveying" of boundaries by my government has traditionally been the first step in the staking of claims and the erection of fences and walls. When does the landgrab start? I want to plan my flag on a choice piece of real-estate. *g*
So, I have a question. Why is it that when scientists talk about exploring the edges of the solar system, they insist in sending probes "out past Pluto"? On the one hand, I understand why we do so - our solar system does lie (primarily) in a plane, so it's natural to think that way.
But I argue it'd be easier to explore phenomina at the edges of our solar system by going in the third dimension - orthogonal to the plane of the solar system. After all, the Sun isn't just radiating in a 2-d plane. Or am I wrong in my assumption about how solar winds radiate?
Any scientifically sound reason why this is a bad idea?
Or are we doomed to continue think as Khan did/does/will? *grynn*
---anactofgod---
"Equal opportunity swindling - *that* is the true test of a sustainable democracy."
Why do we need this? Someone please explain it to me. None of the Pioneer or Voyager probes have yet to reach the heliopause and they were launched in the 1970s. So we should expect to see results in sixty years? How about doing some USEFUL exploring like investigating Pluto/Charon and KBOs?
"Well Ranger Brad, I'm a scientist. I don't believe in anything." - Dr. Roger Fleming
I think this is a good idea. I just wish that they would save Hubble. They way they are dealing with Hubble is like junking your car just because it needs a new battery.
Hmmm... my girlfriend tried that logic too...
Uber-brief introduction to energetic neutral atoms: Ions (charged particles) are susceptible to magnetic and electric forces. As a result, they can be boosted to very high energies in certain situations, but also usually can't travel very far before being modified in some way by electromagnetic forces. If, however, an ion interacts with a neutral (charge exchange), it can "steal" one or more electrons from the neutral without substantially changing the energies of either, leaving a nonenergetic ion and an energetic neutral, which then leaves the vicinity as it is no longer subject to EM forces. We can observe these ENA's and infer properties of the acceleration region.
Escape velocity is for a ballistic trajectory. Ballistic, meaning unpowered after the launch. That is, if you chuck a rock at sea level upwards at that speed, it will slow and slow but never quite stop.
What you're talking about is escaping by just continually going upward, like climbing a ladder. Which you could, if there were a big enough ladder - but of course there isn't. So rather than standing on a solid, you have to continuously accelerate against gravity to even stay put. Possible - it's what a Harrier jump jet does when hovering at take-off - but expensive in fuel, meaning you can't do it long enough to get anywhere useful before the fuel runs out. It makes more sense to burn all your fuel as early as possible, accelerate as fast as possible, and coast most of the way ballistically. That way you get rid of the fuel fast (it's heavy and expensive to lug) and you don't waste effort just staying put.