Asteroid Capture Doesn't Impress Everyone
Planetary Scientists Casting Doubt on Feasibility of Plan to Corral Asteroid, Science (paywall – sorry)
“Asteroid scientists are also a bit miffed that NASA left them out of its planning. They had heard presentations on the concept, but “we just couldn’t take it seriously,” [Mark] Sykes says. By early February, after realizing that NASA was indeed taking it seriously, he offered headquarters the services of its Small Bodies Assessment Group to help evaluate the idea. He got no response. NASA’s Green says that “this is just the start. We will get them more involved.” Although it falls outside their expertise, asteroid scientists have one more complaint about NASA’s latest plan. The whole point of astronauts going to an asteroid had been to gain experience for long-duration missions far from home, such as a trip to Mars. But “if you bring the asteroid to the astronauts instead of the other way around,” Harris says, “you really aren’t sending humans into deep space, or for that matter cutting any new ground over … circling the Earth in the [International Space Station].” So other missions would be needed to gain the necessary deep-space expertise.”
The scientists quoted on the article don’t seem to be aware that, in the proposed mission scenario, the astronauts would be located at a significant distance away from LEO, even beyond the moon. The idea is not to bring the captured asteroid all the way to Earth’s vicinity. Of course, that corroborates their point regarding how NASA left them totally in the dark.
At interplanetary scale, the Moon is practically next door. We have lots of experience in that category from the 60’s/70’s.
However, you would have accomplished several goals, that will be needed for a manned mission OUT to the asteriods, 1) you will gain knowledge of how to work around an asteriod, 2) you will now have an established surface base at the L1/L2 point.
While I would prefer a more expansive program that develops an industrial capacity on the Moon, the asteroid capture mission and return to cislunar space does have practical value for future solar system industrialization.
I would make a few suggestions.
Move the object to Earth/Moon L5 rather than L1 or L2. The reason is that the L4-L5 libration points are stable, requiring no propellant to maintain the orbit of the body brought back. There are some scenarios where an L1 or L2 object could exit the portal to an Earth intersect.
The second suggestion is to do a very thorough spectral study to make sure that the body has significant economic potential, not just a science project. That is, the body should be metal or something like a carbonaceous chondrite with lots of carbon and hopefully hydrocarbons and water.
These two things would absolutely make the mission worth doing.
Doing it at L5 is icing on the cake to us Gerry O’Neil fans.
Given that L4 and L5 are stable orbits, rather than stable points, this would also force us to learn/exercise other useful techniques in navigation and station-keeping.
If the asteroid is at L5 how do we get rid of the bits we do not need?
Or does Venus clean L5 out?
Each Lagrange “point” has an escape velocity, just like a planet or any other object with mass/gravity. You’d probably use an expendable bare-bones “garbage truck” spacecraft to collect up junk then launch it on a trajectory into the Sun. You wouldn’t need a lot of thrust to do that since you aren’t too concerned with how long it takes to get to the Sun. It doesn’t have to be the Sun, but we should get into the habit of no longer littering space.
Of course, depending on what programs are happening at any point in time there may not be any bits we do not need. One man’s garbage is often another man’s raw materials. Even common rock/stone and rock dust will have their uses in space, lunar and asteroid programs.
Having a ore and mineral processing facility in relatively close travel time to earth would be wise in terms of safety and operational success of such a project.
If the goal is planetary science rendezvous with a sample return to earth would be more cost effective. If the goal is building factories in cislunar space we would still need far more infrastructure than can be launched at current prices.
Yea it requires a lot of infrastructure….
http://www.youtube.com/watc…
http://www.youtube.com/watc…
If it were a metal asteroid nothing more complex than a solar mirror, some magnets, and a couple of extruders would be needed.
Quit trying to over complicate things!
Sykes et al had been busy trying to make the case that there are no viable targets for human asteroid missions (through their Target NEO workshop), in hopes that NASA would fund a space telescope at Venus to find more asteroids (even though Venus isn’t a good place to search for smaller asteroids). Now that they’ve convinced people that the human asteroid mission can’t be done they are just mad that NASA found a creative new way to meet the objectives of that mission without giving them a couple of billion for their space telescope. Now they’ve got a second Target NEO workshop planned… how much do you want to bet it will conclude that this asteroid mission also can’t be done without first buying a Venus telescope.
One of the hoped for spinoffs from this proposed program is a planetary defence system. This will require inspace telescopes to keep watch.
In the near term we need to find several possible target asteroids. Programs like this almost always slip so we do not know which year the SEP will be launched. About 6 months before launch, when the SEP and bag are ready, the target asteroid can be chosen. A list of possible asteroids covering several years will facilitate this choice.
Though it would be a good technical achievement to bring an asteroid to the vicinity of the moon, there would really be a limited number of exploratory missions that could be launched to a 25 foot rock. I’d rather see us spend the money on a lunar lander to open a gateway to a much bigger world. There are those who say we have been to the moon but that would be like saying the North American continent had been explored if we had achieved six landings here from another
world or if the Europeans had quit coming over after a half dozen trips back in the late 1400 and early 1500’s. We need a meaningful exploration program for the 2020’s with us not being ready for Mars until the 2030’s or later. The SLS is a key element but has any kind of flight rate been committed to at this point besides perhaps 3 test launches? Imagine the space shuttle having been developed with no goals of how many missions a year to fly. At least we set our
sights high at 25+ missions a year even if we didn’t quite get there. Let us commit to at least four lunar landings a year in the 2020’s to give us a strong space program and a mission that will enable us to maintain our ability to manufacture the SLS for the day when it is eventually needed for Mars missions.
“The whole point of astronauts going to an asteroid had been to gain experience for long-duration missions far from home, such as a trip to Mars. But “if you bring the asteroid to the astronauts instead of the
other way around,” Harris says, “you really aren’t sending humans into deep space, or for that matter cutting any new ground.” So other missions would be needed to gain the necessary deep-space expertise.”
Augustine concluded that NASA’s budget should match its mission(s) and goals.
Sadly, the asteroid study has been compromised to create a mission for SLS/Orion which can be summarized as a 4 hour space walk and wants $105M to study the merits of a plan that simply keeps prohibitively expensive SLS/Orion in the mix. It should be quite easy to compare the costs of using the existing fleet versus spending $2.5B/year for SLS/Orion plus adding in past development costs, which consume the entire HSF budget with little remaining for anything else, about $40-50B.
JSC director Ochoa summarized the asteroid return idea “because it doesn’t require development of another new human spacecraft which would mean a lot of new money” {but does not add: if one continued to fund SLS and Orion}.
The mission tries to extend the duration of Orion to weeks, which is not required for the one year round trip to Mars, nor for the moon which requires days to perhaps two weeks. Dumbacher states it best: “Orion gives us 21 days….what is missing is the habitat module…for longer duration missions. Once Orion attaches to the habitat, it would remain…powered-down”. http://www.americaspace.com…
This will not be last time one hears that “HLV and SLS are critical to beyond earth orbit and journeys to mars”, but sadly, the existing fleet can achieve the same missions for 10s of billions less. At one time it was the moon twice a year and mars once a year. Now its one 4 hour space walk.
The mission sets will grow and the more technology challenges will be addressed once the country steps up and recognizes compromising and keeping the leftovers of the Constellation HLV architecture prohibits NASA from moving forward with any logical mission, mars and moon are off the table, and asteroid mission is now compromised, as pointed out by the team of scientists, with no input into the process once again.