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NASA just released an online 'trajectory browser' which generates spacecraft trajectories from Earth to the planets and known small bodies in the solar system. It does have some constraints, such as being limited to missions launching before 2040. However, I think it is a powerful and useful tool, especially for those without the time for experience needed to do the calculations themselves.
You can check it out here:
http://trajbrowser.arc.nasa.gov/traj_browser.php
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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Thanks for that. Very useful. I wish though they didn't put a limit of 20 km/s on the total delta-v of the mission. If you have orbital depots, then you can have unlimited fuel, which allows significantly higher delta-v's.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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You are welcome! I am glad someone else found it useful.
I too was disappointed by the 20 km/s delta-V limitation. On the other hand, I am very impressed by the gravity assisted trajectories it has cataloged. This makes it particularly useful for playing with Outer System missions, where a slingshot maneuver or two is standard fare, but rather challenging to compute for the typical space enthusiast.
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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Midoshi:
Do you know what orbit that the Kepler telescope is in? Could this trajectory thingy get us a trajectory to rendezvous with it?
I ask, because repairing Kepler would be a very worthy mission for men to undertake outside LEO. The more-challenging analog to repairing Hubble. And that had very widespread support. Both in Congress and among the people.
Something like that is the kick-start needed to get men flying beyond LEO again. Get that done, and Mars is not far behind, asteroids or not.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Midoshi:
Do you know what orbit that the Kepler telescope is in? Could this trajectory thingy get us a trajectory to rendezvous with it?
I ask, because repairing Kepler would be a very worthy mission for men to undertake outside LEO. The more-challenging analog to repairing Hubble. And that had very widespread support. Both in Congress and among the people.
Something like that is the kick-start needed to get men flying beyond LEO again. Get that done, and Mars is not far behind, asteroids or not.
GW
If the electronic components are modular perhaps we can send a Dragon carrying Robonaut to swap out the malfunctioning reaction wheels for new ones.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
Online
GW:
Kepler is in an heliocentric orbit trailing the Earth. It has a period of 372.5 days, and was specifically put in that orbit to avoid interference (both gravitational and electromagnetic) from Earth and the Moon. While it will come "back around" on its own in about 50 years, that's a bit long for the current situation! Since it's in an Earth-like orbit there is a nearly linear trade-off between delta-V and mission time.
The reaction wheels are mounted in an external and accessible location. However, I can't speak to how difficult it would be to deintegrate and install a new one.
Kepler is actually operated from where I work - the Laboratory for Atmospheric and Space Physics. We got an internal e-mail about the situation the day it happened, but I think all the info it contained has since been disseminated in the press. I haven't stopped by the mission control room recently, but I bet it's pretty hopping right now.
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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Midoshi & Bob:
Since Kepler is in a trailing orbit, I'm assuming one gets there by an ellipse outside Earth's orbit, with a period that differences from our year by just enough that its perihelion hits Kepler's location. The delta-vees for that ought to be fairly modest (once escape is achieved), but I'd bet the transit time is a few months, not days or even weeks.
Not much different from going to Mars!
Any ship capable of hauling men on that mission could also be used to go to Mars. You just don't need landers to visit Kepler.
For months one-way, you will need radiation protection (a shelter with 20 cm of water) and you will need artificial gravity (centrifugal force). Life support can be stored supplies, especially adding some frozen food, since the round trip is likely over a year (about the limit for our "astronaut foods" as we know them). It wouldn't hurt to consider meteroid protection and repair (foam/foil layers seem to work well and are also good insulators).
I think a manned repair mission to Kepler would be a good rehearsal for all but one critical piece of hardware needed for going to Mars (that would be the lander).
Many would argue that artificial gravity is the "killer", but it is not. Especially if your vehicle is the constellation of docked modules that it has to be, if we use the rockets we already have to launch it! You just dock your modules (mostly propellant tanks) in a "slender baton" shape, with the habitat at one end, and spin it end over end. Very stable, as demonstrated in Friday night football stadiums all over the country.
As you expend and jettison tanks of propellant, you reconfigure to maintain the same length "baton", just skinnier. Brief intervals of zero gee we know how to handle while maneuvering, but for the long coasts, artificial gravity makes both life, and life support, a lot easier.
Guys, this could be done within 5 years by the right team, and that's just a couple of design/checkout-test cycles. We actually could have done this several years ago, just like we already did building the ISS. It's very little different. Experience then makes it cheaper and quicker now, too.
There's an overall purpose for NASA-as-an-agency there, if ever I saw one. But I'd rather see someone not stultified into rigidity (meaning non-governmental) actually do this. That's how one does this for less time and money.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Midoshi, I just saw the URL. Are you out at Ames now? I just left Ames for the private sector, but I'm still in the valley. Maybe we could get a coffee sometime.
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No, I'm now at LASP in Boulder, CO working on the IUVS instrument for MAVEN. But let me know the next time you're in town and I'd be up for grabbing a coffee. And I can let you know when I next have a reason to be near the Valley.
"Everything should be made as simple as possible, but no simpler." - Albert Einstein
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Midoshi & Bob:
Since Kepler is in a trailing orbit, I'm assuming one gets there by an ellipse outside Earth's orbit, with a period that differences from our year by just enough that its perihelion hits Kepler's location. The delta-vees for that ought to be fairly modest (once escape is achieved), but I'd bet the transit time is a few months, not days or even weeks.
Not much different from going to Mars!
Any ship capable of hauling men on that mission could also be used to go to Mars. You just don't need landers to visit Kepler.
For months one-way, you will need radiation protection (a shelter with 20 cm of water) and you will need artificial gravity (centrifugal force). Life support can be stored supplies, especially adding some frozen food, since the round trip is likely over a year (about the limit for our "astronaut foods" as we know them). It wouldn't hurt to consider meteroid protection and repair (foam/foil layers seem to work well and are also good insulators).
I think a manned repair mission to Kepler would be a good rehearsal for all but one critical piece of hardware needed for going to Mars (that would be the lander).
Many would argue that artificial gravity is the "killer", but it is not. Especially if your vehicle is the constellation of docked modules that it has to be, if we use the rockets we already have to launch it! You just dock your modules (mostly propellant tanks) in a "slender baton" shape, with the habitat at one end, and spin it end over end. Very stable, as demonstrated in Friday night football stadiums all over the country.
As you expend and jettison tanks of propellant, you reconfigure to maintain the same length "baton", just skinnier. Brief intervals of zero gee we know how to handle while maneuvering, but for the long coasts, artificial gravity makes both life, and life support, a lot easier.
Guys, this could be done within 5 years by the right team, and that's just a couple of design/checkout-test cycles. We actually could have done this several years ago, just like we already did building the ISS. It's very little different. Experience then makes it cheaper and quicker now, too.
There's an overall purpose for NASA-as-an-agency there, if ever I saw one. But I'd rather see someone not stultified into rigidity (meaning non-governmental) actually do this. That's how one does this for less time and money.
GW
For a manned mission of months duration I expect a lot more planning and development time than just five years. And there also will be the large cost involved. As you said it would be comparable to a flight to Mars.
The Obital Science's Cygnus capsule though is only 2 metric tons in dry mass. We would not even need to give it life support if carrying Robonauts.
I did a calculation and I was surprised that a even a medium class launcher such as a Delta IV Medium or Atlas V without side boosters or the Falcon 9 could launch this to escape velocity. This means a Cygnus launched on such a comparitively low priced launcher could rendezvous with Kepler or even make a circumlunar flight.
This last is what I am particularly interested in. The private lunar flight ventures such as Golden Spike have been viewed with skepticism because it is thought such missions have to have multi billion costs and be backed by national governments. Indeed even to do circumlunar missions with Apollo required the Saturn V launcher, or the SLS for the Orion capsule.
Then imagine the psychological impact of such circumlunar flights manned first by Robonauts and followed by ones with a human crew that only needed a medium class launcher to accomplish, something NASA typically uses for its smallest, lowest cost planetary missions.
It would bring home the fact that simply by going small manned lunar landing missions can also be accomplished at greatly reduced costs than thought.
Bob Clark
Last edited by RGClark (2013-05-27 08:30:41)
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
Online
Adequate planning time and preparation time for a Mars/asteroid/Kepler repair mission are a lot less than most today seem to think. 5 years is good, 10+ years is ridiculous. We did Project Mercury with about a year or two's worth of prep time.
As far as a mission to an asteroid (or Kepler) goes, "they" have had decades to think about such things, and have quite demonstrably failed to do so.
I would welcome some private entity like Spacex or Orbital Sciences busting onto the scene with some plan to do what NASA currently thinks cannot be done. I am quite tired of government bureaucracy screwing this up: screwing-up something that could have been done at least 20 years ago! The original NASA plan for a manned Mars landing (inadequate as it was) dates to a launch in the 1980's, well over 3 decades ago.
If you pay attention to to microgravity disease prevention, radiation protection, and 3-years-worth of life support, there is (and has been for a long time) no reason we could not do this (Mars or asteroids or anything similar) right now, from a technological standpoint.
Going to Mars, an asteroid, or Kepler, requires just about the same kind of ship. Only Mars requires a lander. So, what's the big deal? Why can we not do this? Why haven't we done it already? Especially since technical solutions to every single problem are known, and have been, for a least 2 decades now? Bureaucratic ineptitude? That's no answer!
I admit Cygnus or something similar could go to Mars or an asteroid or Kepler right now with some sort of robot. Absolutely.
We've sent robots to Mars since 1965, nearly half a century ago! But, historically, the fundamental desire has been to send men! It would not have worked in the 1980's, but it can now.
And now that we can, and we have been capable of this for over 2 decades now, we should. So, why not?
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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You are welcome! I am glad someone else found it useful.
I too was disappointed by the 20 km/s delta-V limitation. On the other hand, I am very impressed by the gravity assisted trajectories it has cataloged. This makes it particularly useful for playing with Outer System missions, where a slingshot maneuver or two is standard fare, but rather challenging to compute for the typical space enthusiast.
Midoshi, there appears to be a bug in the system. Perhaps you can ask them about it. Even though I put in 20 km/s delta-v and selected one-way flyby, it returned only trajectories at about 5 km/s or so total delta-v. This results in one-way travel times at 80 days or above, when it should have been much shorter than that.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
Online
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