Category Archives: Asteroids!

Reasons to Arm Wrestle – Item 5

Demonstrating large-scale solar electric propulsion (SEP) systems.

This is one of NASA’s main interests in the ARM mission — in the land of expensive launch vehicles, very high specific impulse propulsion, like you can get with SEPs, can make many missions a lot more affordable. Even with low-cost Earth-to-orbit transportation, SEPs probably make sense for a wide range of missions. Demonstrating the ability to use large-scale SEPs for tugging huge objects in heliocentric space, performing precision injection maneuvers, etc., might be very useful.

The goal of high-isp interplanetary transit is indeed what I would consider an enabling technology for colonizing our solar system. Without it, there just isn’t any way to get the mass of hardware and logistical items where you need them to survive in extraterrestrial locations, at least in near-term scouting missions. When ISRU can be reliably counted on at each location we colonize, that picture changes at least theoretically, for that local colony. However, we end up in the same situation again as we hop from location to location in our system, and we must be able to take our needs with us to each new place.

Now for crewed missions in general, we need high-isp capability to keep trip times low, and avoid the years-long travels that we have long taken as a given. SEP propulsion systems don’t address this directly, being ill-suited for long-term use in transporting crews and all the large systems they require. Developing SEP to a higher degree of sophistication does bolster the mission design for unmanned cargo systems, of course, and that would reduce the burden on crewed missions somewhat by offloading some of the logistical burden. Essentially, the SEP systems for colonization efforts would be relatively slow-moving uncrewed cargo ships sent ahead for later rendezvous with much faster crew carrier spacecraft. For the carriers, other bootstrapping rationales would be needed to co-develop technology like VASIRM, where the power density is much higher than that of solar-powered ion engines.

Reasons to Arm Wrestle – Item 4

Providing a good way of testing out a man-tended space habitat.

One of the ideas NASA is looking at incorporating into ARM is attaching a prototype deep-space habitat. This would allow visits of up to 60-day duration by crews of up to four. While there are other ways you could test something like this (such as Lagrangian point L1/L2 gateways), testing it in an operational environment would be useful, as would demonstrating the ability to do long-term habitation in close proximity to an asteroid.

Now, there are good reasons for testing habitations at Lagrange points, I grant you. For one thing, being able to establish the means of setting up waystations along a path or set of paths to service a greater exploration and exploitation of our solar system is invaluable. Having a predictable nexus for inbound/outbound spacecraft is better for a the kinds of manufacturing, materials processing, and even passenger-handling systems that have proven so effective for the past couple of centuries. And such waypoints’ efficiencies will be highly optimized by the systems themselves determining where they reside in space, not merely making do with what exists out in the heavens.

However, Goff is absolutely correct that testing habitat technologies would be well-served by setting up shop on asteroids first, for a couple of reasons:

Firstly, we don’t want to be endlessly floating in space watching as we glide past or around the objects we really want to set foot upon. Landing a habitat on an asteroid satisfies at least that human urge to explore. But, more than that, it allows a much smaller effort there to be extrapolated to more demanding landing and living missions to places like Mars, and we can learn a lot more with less fuss. A big driver in Mars landings is that we have a much more difficult time achieving safe entry and landing speeds from the planetary approach, as we lose most of the atmospheric braking advantage we enjoy landing on Earth. To fix that, we generally either have enormous parachute size (and mass) to catch what little air there is on Mars, or we carry even more enormous amounts of mass in the form of landing propellant. Airbag landings, while shown feasible for our robotic missions, are not reasonably safe enough or predictable enough to land human systems, up to and including the humans themselves.

In contrast, recent missions such as the Dawn orbiter mission to the dwarf planet Ceres and the Rosetta mission to Comet 67P show that we can indeed orbit exceedingly small objects in space where asteroids reside, and can even land on them. The propellant mass to perform those landings is quite small.

Secondly, by setting up crew-tended shop on asteroids, you can tackle more than one thing at a time. You can credibly test the habitat while the crew actually performs the needed inaugural experimentation needed to assay an asteroid. You end up learning more than one thing at a time that way.

So, until issues with landing downmass and technology for more demanding crewed missions are worked out, the habitats-on-asteroids mission profile allows for early-term validation of off-world living while concurrently pursuing industrial research.

Reasons to ARM Wrestle – Item 2

Providing an ideal testbed for asteroid in situ resource utilization (ISRU) development

 

 

Many people see asteroids as the premier source of vast quantities of off-world resources. But while there is no shortage of low-technology-readiness-level concepts for how to extract resources from asteroids, actually testing those out isn’t going to be easy. I think testing will be much easier when you have the ability to send people and robots, when you’re close enough to Earth that teleoperation of robotics is a viable option, when you have frequent repeat visit opportunities where you can try new approaches, and when you can do your testing in a microgravity or near-microgravity environment, like you would have at an asteroid. Prospective asteroid miners like Deep Space Industries and Planetary Resources probably wouldn’t complain about having one or more easy-to-access testbeds to work with.

If I understand this correctly, the chief advantage discussed in this item of the ARM mission is that we can bring back that first asteroid to a location close enough to reliably revisit it to test ISRU techniques. I think this is an excellent consideration for the early years of asteroid resource exploitation.

Why not use a now “localized” asteroidal body as a testbed for ISRU trial-and-error technology development? It is certainly better than using trial-and-error on fairly long manned missions to asteroids, it would reduce risks considerably. This is a similar rationale as has been advocated by Moon-before-Mars development, where living accommodations and travel considerations can be normalized in a location that is relatively close to Earth. We could do a lot of shakedown cruises for long-distant manned survey spacecraft. The needed waystation habitat on the ARM asteroid would provide practical experience in developing and improving the long-to-permanent-duration habitats we will require to colonize and explore our system neighbors. The trip recycling time for launching new missions will be much shorter for reaching a site in Earth orbit than heading out to other bodies orbiting Sol, as well. This brings down a great deal of risk per mission flown, and also allows more flights to the testbed site in a given period of time.

Of course, it can’t be that way forever, or the In-Situ character of ISRU is meaningless. For proper colonization of this solar system, we’ll need to be able to really live off of the land, and ARM only opens the door. Real ISRU keeps it propped open.

Reasons to ARM Wrestle – Item 1

Jonathan Goff’s first point in reasons why NASA ARM missions may be a good thing:

    Adding a new, even more accessible “moon” to the Earth-moon system.

A lot of people fixate on the fact that we’re going to spend all of this money for a couple of astronauts to go out to a rock in lunar orbit, climb over it for a few days, and bring some samples back. What they conveniently ignore is that more than 99.5 percent of the material brought back to the Earth-moon system will still be there, orbiting the moon for the next several hundred years, in a fashion that is easily revisitable for a long time.

See more at Goff’s original article.

http://spacenews.com/op-ed-10-reasons-why-an-asteroid-redirect-mission-is-worth-doing/#sthash.pProh729.dpuf

That is something that most naysayers like to start with, the initial cost-vs-benefit. Certainly, if all we did was go to an asteroid and take a stroll, never to return, that would be a low value for the funds spent. I think that’s a strawman argument, or could be made into one by how we proceed after capturing the space rock and hauling it to lunar orbit. Given the abrupt end of Apollo, the truncated capabilities of Shuttle versus what was promised in the 1970’s, and any number of other stillborn efforts over the years, you can’t blame people for being cynical. What’s to say that we have a grand plan for asteroid mining that gets us one ARM flight, or maybe two, and then we distract ourselves and don’t go any further? The thing is, we could do that model of halting exploration again and again, the destination doesn’t really matter. So, what to do about it?

You have to do what Goff suggests – you plan your work and work your plan. Yes, go make that first historic manned asteroid landing and sample return mission, it is an exciting prospect. It would be farther than we’ve been with humans, and the materials returned would be fascinating from a geological and mineral assay perspective. It would also be a pointed and irrefutable demonstration that manned spaceflight was back, and in a big way. But there has to be more. Flags and footprints are showy and energizing for a time, but if that’s all there is to it, then why do it? For most of us in the space industry, we see a vision where space-based resources are the future, and crave progress towards such exploitation. We want to digest the asteroids and metabolize them into the technological muscle, sinew, and bone of our species’ spacefaring body. That needs to be made clear.

Basically, I think it should be openly acknowledged that we have run to Apolloesque flags-and-footprints rationales in the past, and the mission planners, and the spokesmen for the mission, and anyone involved on any level need to be very clear that the plan is not more of the same. No more sprinting to a dead end, then starting over. The architecture of the mission needs to be concretely understood as being directed to exploitation of the exploration, not exploration for exploration’s sake. It has to be understood that ARM is a big step that leads to the even bigger steps we need to make into extraterrestrial space.

Good Thoughts on ARM Wrestling

One of the subjects near and dear to my heart is the avoidance of Earthly extinction via asteroid or cometary impact. We should be working diligently to get off this planet and spreading ourselves around, and we are, though at an excruciatingly slow pace. It would be so much better to not be a single target for some wayward rock to take us out. The sooner, the better.

Another issue of great importance to me, which serves the first, is the exploitation of those same asteroids to build up whatever toeholds we establish off-planet. Again, sooner the better.

Jonathan Goff has written a concise set of ten reasons why the NASA-developed Asteroid Retrieval Mission could be very worthwhile in addressing the above. It may not be the perfect mission, and certainly not the most economical, but it is miles ahead of having no mission. You can read Mr. Goff’s work here:

http://spacenews.com/op-ed-10-reasons-why-an-asteroid-redirect-mission-is-worth-doing

Just to start, I want to list his points here, and over the next several days, I’m going to discuss each of them one by one.

1. Adding a new, even more accessible “moon” to the Earth-moon system.

2. Providing an ideal testbed for asteroid in situ resource utilization (ISRU) development.

3. Providing a much larger sample quantity to work with than other existing or proposed missions.

4. Providing a good way of testing out a man-tended deep-space habitat.

5. Demonstrating large-scale solar electric propulsion (SEP) systems.

6. Demonstrating planetary defense techniques.

7. Developing technologies for a Phobos/Deimos large sample return.

8. Providing the beginnings of a lunar gateway.

9. Providing more experience with on-asteroid operations.

10. Leaving something permanent.

I’d encourage everyone interested in the ARM wrestling match over the validity of this mission to read Mr. Goff’s article.

United Nations to Adopt Asteroid Defense Plan

http://www.scientificamerican.com/article.cfm?id=un-asteroid-defense-plan

Earth is not prepared for the threat of hazardous rocks from space, say astronauts who helped formulate the U.N. measures

“…The U.N. plans to set up an “International Asteroid Warning Group” for member nations to share information about potentially hazardous space rocks. If astronomers detect an asteroid that poses a threat to Earth, the U.N.’s Committee on the Peaceful Uses of Outer Space will help coordinate a mission to launch a spacecraft to slam into the object and deflect it from its collision course.”

While I am not sure that slamming objects into a careening asteroid is the most nuanced (or even effective) response, it is interesting and gratifying that an authority at a higher level is at least planning on having a plan. Ed Lu and Rusty Schweikhart can use their B612 Foundation as a megaphone for action, and even build the Sentinel Telescope mission, but without a greater intention to act, all we can do is watch a disaster unfold. Despite any personal hard feelings that I have regarding the United Nations, this is still very good news.

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