Slashdot Mirror
Space Tug to the Moon and Beyond
An anonymous reader writes "Andrews Space and SpaceDev, a contributor to SpaceShipOne, are building a cargo transport called SmallTug to travel to the Lunar L1 point using a Hall Thruster and running off of solar power. The final craft will be capable of attaching to and transporting satellites 85 percent of the way to the Moon for use in interplanetary missions. The launch date is scheduled for 2008 and it is being designed to be quite inexpensive. The Inquirer has more details."
Part of me wonders why this is not known in detail already, plus wouldn't it be related to solar activity anyway? Solar wind and so forth.
They need to know though, since the trip to L1 will take 1 year.
I remember reading in New Scientist about a decade ago now that you can get to the moon using very little energy- an orbital transfer basically. Catch is, it takes 2 years to get there.
85% Why stop there? If it can get to 1.5 million km at L1 why can't it go all the way to 0.35 million km for the Moon? It seems to me that almost any spacecraft that can get to the 85% of the Moon in a finite period of time can make it all the way to the Moon.
85 = 5*17
2008 = 2*2*2*251
It should be noted that hall thrusters are extremely low thrust but high ISP. This is effectively an ion drive. This means that it's a relatively slow method of doing orbital transfers. In other words, don't expect this thing to drag the satellite L1 in half an hour.
Our nanosat-4 project is using a PPT although we considered an MET for a while. We have to maintain formation flight between three satellites which requires high thrust/quick burn types of thrusters. That burn time ruled out the MET.
Planetes
"One World, One Web, One Program" - Microsoft Promo Ad
"Ein Volk, Ein Reich, Ein Fuhrer" - Adolf Hitl
FYI:
h ighway
http://en.wikipedia.org/wiki/Interplanetary_Super
Once you are on the IPS, it's pretty easy to get where you want with very little fuel expenditures. What I'd like to know is how they plan to get there, since in order to get to the nearest IPS orbit, you probably still need amount of energy, comparable to what it takes to get into LEO. SpaceShipOne lacked the capability to get into LEO by a long shot.
The company's objective is to research, design and develop this "smalltug" spacecraft, not (guessing based on the articles) about putting it into the orbit. Marshall would most probably pick up the bill for that.
Nontheless, $20mil is a good price tag. I hope Andrews Space does succeed in this (and if it doesn't, well, then it won't get any more than the first phase of the 1.25mil budget...I wish we can slap this kind of thing onto NGST, Boeing or TRW).
Ox might have a copywrite lawsuit. Or maybe they would settle for Ox advertising on the side of the spaceship "Brought to you by BangBro's".
Come to think of it, I am suprised Nasa has not sold naming rights yet. If Comisky Park can get 30 million to change their name to US Cellular Field, how much could NASA get to change the name of their space shuttle from Challanger to the Anhiser Bush Space Shuttle. Maybe they could even get a 30 second advertising clip of the astronauts floating in space drinking a cold refersing budwieser. Nike could be next in line, having an exclusive contract to provide all NASA shoes. It could be like what Nike did 10 years ago in college basketball when they paid 7 or 8 of the best college program universities millions of dollars to force their athletes to wear nikes as part of the uniform. When the final 4 came, all 4 universities were in contracts with Nike, and all the basketball players were wearing Nikes. Every 3 hour basketball game was free advertising for Nike, as every basketball player was wearing their shoes. Well, in space, there is only one team, and it would be lots of free advertising when they are interviewed. Maybe Kennith Cole could pay a couple million to help design the artistic look of the new space suits.
With all the different industries that could contribute money for advertising, I wonder how much NASA could get per year? 100 million dollars? 250 million dollars? If you were IBM and you were smart and wanted to keep OS/2 alive, what better advertising could you have then to have your OS used on the space shuttle, to have advertising?
Just imagine every chemist, biologist, mathematician and physicist in the USA, dressed in Nike Moonwalkers, wearing Kennith Cole Space Pleather jackets, with their IBM laptops running OS/2, and drinking a coca-cola before thier big exam or buisness meeting because it is what the astronauts drink before a critical mission.
Rosco: "If brains were gunpowder, Enos couldn't blow his nose."
The second factor at work here is that the private space business doesn't have all the overhead that a government operation does. Look at Spaceship One. No fancy designs, no high priced systems. Just some good old fashioned engineering and the kind of "can do" attitude that made NASA great in its early days. You know how NASA got the first Mercury space capsule to the pad? A sheet of plywood, an old mattress, and a pickup truck. That would never happen any more, and not necessarily because it's a bad way to transport a space capsule. Many of NASA's expenditures are to support its contractor constituency and its public image.
The third and final factor is that NASA's primary mission these days seems to be searching for ET. Don't get me wrong - Missions like Cassini and the Mars Rovers are great, but not because NASA thinks that there's probably life out there somewhere. The commercially funded missions are focused on doing real work that people can understand, stuff like going to the Moon and mining it for its resources. The missions to the outer planets represent a kind of pseudo-science that doesn't have any practical day-to-day benefit. This, of course, is always the problem with science, since the public is less interested in what makes something tick than what it will do for them. But riding the coat tails of ET isn't a good way to approach it. I can tell my friends that Deep Impact will help us understand how comets work and what might need to be done in order steer them away from Earth if they're on a collision course. If we happen to get some great science along the way and better understand the makeup of comets then that's a good thing. It's much harder to make the case that spending billions for Cassini is in the public interest just because there might be life on Titan.
What's ironic is that the ISS was sold to Congress and the public based on its practical merits, yet it can barely support the two occupants currently stationed there. The cost of doing research on board ISS is prohibitive since it is supported primarily with manned flights. When commericial enterprises can start to leverage space at a reasonable expense then that's when we'll see the promise of all the engineering advancements that a weightless environment can provide.
If you don't want crime to pay, let the government run it.
that doesn't really work, even when you are in orbit, in order to increase your distance from the Earth you have to spend energy (the gravity still exists and pulls you down).
So getting in orbit is just the first step. Escaping entirely from the earth's gravity is something different. I think this is the distinction between the first and second "cosmic speed". (I am not sure whether the term is correct in English)
I am curious if you could use alternate types of energy to get into orbit. I mean, there are solar powered planes, it's true they only work in the atmosphere, but as you climb, the atmosphere grows thinner and you could increase speed. If the transition between atmosphere and void is really smooth what would stop you from slowly increasing the speed until you switch from gliding to orbiting.
Does anyone care to do the calculations what speed you would need in order to start orbiting at the edge of atmosphere? (My guess is that it probably is too high, but it was just an idea)
A worrying number of space systems were invented by science fiction writers...
Me (Blog)
Without having read the article I can think of two obvious ways.
1) Solar sail type technology where the photons provide the reaction mass.
2) Ion drive tech where the reaction mass is used much more effectively (>1000X).
I would lean towards the latter case. The tug could get its reaction mass in several ways:
a) Massing missions. Every N-th launch is a remassing mission. This is very straightforward but means that most of the time the tug is carrying around far more mass than it needs.
b) BYOM. Every mission that goes up carries a cartridge of reaction mass to give to the tug. This seems like the most elegant solution since the amount of mass required per mission is only a tiny fraction of the payload and the tug would never have to move too much extra mass.
c) Recycling. The tug could recover mass from orbiting space junk or from the mission's packing materials. Eventually, this mass could come from the moon or asteroids. You would need some kind of space factory to do this and the other alternatives should work almost as well . I don't think this makes sense until the program is well established and some craft are no longer involved in directly assisting planetary launches.
d) Supply dumps. Like approach (a) but most of the supplied mass is left in a higher orbit where the tug(s) can load up as needed. Doesn't provide any advantage over (b) in the short term but again it could be useful when there's a need to operate continuously in high orbit or in interplanetary space.