Tip:
Highlight text to annotate it
X
Olson: Okay, Ladies and Gentlemen it's time.
One o'clock, welcome back.
Hopefully everybody had a full and satisfying lunch.
We have an exciting afternoon for you.
First up is going to be the Technologies and Capabilities for NEOs: A Human Mission To A
NEO and so we have Barbara Wilson who lead that group.
And we also have Eileen Stansberry and Chris Moore who are the respective facilitators.
So, without further ado, we'll let you go ahead and do your out-brief and then we'll open
it up.
Again for today's format we'll do 15 minutes of brief and 15 minutes of Q and A then
we'll step to the next group and we have three groups here from one to two thirty.
Wilson: We had a really lively two hour long discussion in our group and I will state
from the beginning that what is up on the charts is a little less than half of what went
on in the group at best but we did try to capture what the individuals in the group found
the most important to capture.
The desired outcome from this group was the identification first of the capability gaps
that you would need to close in order to meet the types of objectives that we discussed
yesterday at the workshop for human NEO mission.
To individually rank those capability gaps as to the importance of needing technology
development in order to close them before it would be reasonable to fly the mission.
And then, after having identified which ones we thought were most important individually
then we went and looked at what kind of technologies and technology development were
options to in fact close some of those gaps.
So the questions followed along the same lines but I want to make a very clear point so
it is on the record that the only part of the mission that we in fact considered was the
on-sight part of the mission.
Obviously the launch, the getting there, the on-sight part, the getting back, reentry
through earth's atmosphere, et cetera, all have technical challenges and in many cases
some of our panel members felt possibly more important than the ones we actually talked
about on-sight but we had decided that that was going to be the focus of this activity.
And in particular, you have to focus on the on-sight part which is NEO specific and we
were very hopeful that the other parts would not be ignored in the following technology
analysis for the future.
So, from the objectives that came out yesterday and the discussions yesterday and also a
precursor question that I sent out to our group asking about where they say the primary
challenges for operating on or near a Near Earth Object.
We ended up using a set of four categories to try and structure our discussion and the
idea was to capture areas that are relatively independent so that it's pretty clear what
goes where in the categories but that also both span the space of key technology or key
capability gaps and stimulate discussion in all the important areas so that we don't
leave any important areas out.
So our categories were called 'Prox Ops' which is associated with all of the operations
near or on or under the surface of the near earth asteroid.
The second being the question of actually the 'Characterization' of the target, both
surface, material, internal structure, et cetera and the handling samples and the
gathering of samples and handling of samples to maintain their pristine characteristics.
The third one we called 'On Your Own' or 'On Our Own' if you're the one there with the
idea that you are far from any repair service, you don't have a logistics train coming up
easily to help you out so we were looking at things like reliability, mission system
autonomy and robustness for how to operate at this distant place away from ground
support.
The fourth one we pulled out just to make sure that we put an appropriate emphasis on
human systems so even though life support obviously has the same issues of robustness,
mission autonomy, reliability et cetera, we actually included life support out in the
human systems but also dealt with all of the aspects of human health and performance.
We had a category for 'Other.' As you can see we did actually get one item that didn't
fit in with the rest of them but by and large these categories seemed to work pretty well
for our group and had a pretty uniform, a good set of stickies that went up on the board
that are listed, just the number on the right, have not pulled duplicates but the idea
was that there was a lot of action and interest in all of these groups.
We also just as a cross-cutting comment that the reliability, autonomy and smart systems
seem to be recurring themes across many of the discussions.
So I will now move through each of these areas and what's shown here on the left hand
side is when we each ranked how we saw the importance of these gaps, we first did it at
our own tables and then afterwards we also did it scoring the other tables after we heard
of what the other tables' thinking had been so we actually ended up with multiple rounds
of scoring and looking at that it turns out then, like for the first one that they
were...
You could score three points for your top one, two points for your next one and one point
for the one most important after that.
And so that is just the count of the scores that came in from individuals.
So among the top four in the proximity operations area, first is the actual touchy part
of the interaction with the NEO.
From an EVA perspective or robotics and anchoring yourself to be able to get around and
touch and interact with any point on the surface.
So in terms of technology development options we didn't have a chance to talk these
through in great detail so we just looked types of areas that should be considered for
potential development and they included things like jet packs for getting around, other
ways of anchoring and/or tethering yourself to the surface, a suit lock for a fast
ingress, looking at tele-operation of robots and the whole human robotic interaction was
a big part of the discussion also and how you operate with both humans and robotic
systems most effectively and efficiently.
We have the whole suit and robotic systems in general, the MMSEV, the man-in-a-can, the
working around the surface in a system again with the suit locks potentially, free
flying, there were some ideas on free flying lighting and cameras to support the
activities.
A clean suit in terms of, this came up a number of times both with the exhaust or
effluence, et cetera from all of our human systems and or space craft systems, that we
don't want to contaminate the surface that we are trying to look at so we have to be
concerned about approaches that look at keeping, for measuring ourselves when we get
there.
There were also concerns about dust mitigation, electrostatic issues and tools for EVA
and although it's captured elsewhere, the idea that if you're going to try to anchor and
put instruments down, et cetera, you need to understand the local subsurface
characteristics for being able to work at that location on the NEO.
Coming in at number five was the 'Spacecraft' part of this where you are in the vicinity
but presumably this is the part where you're not actually touching or interacting with
the surface but you're hanging around in station keeping rendezvous and there are a fair
amount of gaps in that area that could use technology development which includes the
control systems for working in this environment with non-uniform gravitational fields,
things rotating.
It's a very complex and unknown problem in advance when you get there, sensors for
understanding your situational awareness and your position determination which could be
radar, lidar, other, you need to be fuel efficient if you're going to be flying around
and accessing all these different places and/or stations keeping.
You have to be able to do this without using tremendous amounts of fuel because you have
to bring it all with you, of course.
Then, there's an aspect associated with, I talked before about plume and impingement in
terms of contamination and also the whole idea of the information systems, the smarts for
modeling and algorithm, et cetera for terrain relative navigation because you need to use
the body that you're actually trying to stay near to for your Prox Ops.
In the 'Characterization' area while we had a lot of identified capability gaps, when we
came around to voting, most of the individuals found other areas being more important in
terms of the top four or so but these two did come in with notable scores, nevertheless.
A number of people found them still very compelling and the first is associated with the
actual sampling and prospecting so it's acquiring the samples, drilling, coring, getting
the samples from the sub-surface, local anchoring, as I mentioned before, so you could,
in fact, apply forces to do this drilling and coring or other ways of interacting with
the interface and therefore knowing what's underneath there locally, but there's the need
to want to try to understand whether, indeed you are talking about a rubble pile or a big
rock or a loose conglomeration, et cetera, so you need approaches and instrumentation for
sub-surface characterization which still has some challenges also.
We also talked about the idea of maintaining the sample pristine after you pull it out so
you have both the encapsulation for return as well as making sure you don't lose your
volutes in the samples.
We talked briefly about planetary protection.
I think in generally from an asteroid perspective this isn't a major issue.
There's the forward contamination that we did talk about previously.
And then of course the approaches for measuring things so that you are in fact selecting
your best samples so the triage aspect of being able to being able to select the best
sample so you need activities, you need to be selecting where you pull the samples from
in an intelligent manner.
Actually, then doing some of the science that you want to do while you're actually there,
that you need onboard laboratory capability which therefore requires that this
instrumentation be much smaller than the labs back home.
In our own laboratories here on the ground, some miniature instruments, expert systems
that try to speed up the analysis and try to understand what it is that you are trying to
look at and decide what you're going to bring back, a good bandwidth of communication for
being able to send results that you get back and have additional support from the ground
and, we need clean containment of those samples so there's a strong sense here of focus
on subsurface and interior structure and on on-sight analysis.
In the 'On Your Own' category the first one is associated with the autonomy, the ability
to solve stuff, to do stuff by the crew that is there mostly because of the light time
issues, you've got to make decisions based on the full impact of the situational
awareness that that you were the only ones who have that.
So there were a number of activities that were associated with the system autonomy and
automated planning and mission operations including designing for reconfigurability and
adaptability in your systems, artificial intelligence, the health monitoring,
understanding the status of your systems and certainly on-board mission planning as
opposed to can sequences, you're going to have to redo and understand in a flexible way
how you're responding to the environment and what you're going to do next.
And likewise, just in time training because you've got a new set of things that you've
got to deal with that you couldn't have planned for exactly on the ground.
Also here and seen by fewer of our members as highly critical was the whole question of
reliability and repair although this was especially for feed forward perspective, that
for longer missions downstream, system reliability is going to be key.
You don't have service coming in to help you out, you don't have a logistics trainer, you
have to take everything with you.
So, being able to in fact have functional redundancy, common components that you can
share so that you don't have to have a spare part for everything, you can have a few that
handle and support a number of different systems, a robust ecosystem which is both a
function of, the reliability so you don't have things breaking that you've got to replace
and also that you aren't having to bring up as much in the way of consumable filters, et
cetera in the system to be able to have system that will continue to function while you
are there far away from home.
To some degree the question as to whether you can do parts manufacturing on demand,
on-sight and self-repair and fundamentally, that you are designing for sustainability and
reliability.
And we also have put in place test programs to understand the full reliability of our
systems.
So, some of the key points that came out of this discussion where the autonomy and
reliability are key, that we have to think about the architecture in terms of logistics
and sparing and we also, as I didn't mention in passing but should have on the list,
default detection, isolation and recovery and the whole architecture for that approach is
to how to do that when you, in fact, can't have your backroom full of the experts and you
have to have a lot more autonomy on board that deals with faults that will happen and how
you recover from them.
The final system in the human systems arena, both of these were in fact the top two out
of our entire discussion and the first is in terms of radiation protection and warning to
both detection and warning and understanding how much dosage that you've had.
Prediction model shielding and shielding design and approaches and if that can be done
with low enough mass that you can effectively bring this with you.
And the potential for pharmaceutical countermeasures and understanding what each crew
member has been exposed to but likewise in general for radhard systems and to shield the
whole vehicle as well as the human side.
Also the high reliability of human life support, so this is the counterpart of the rest
of the systems on board for high reliability, for the human side it was thought to be the
highest category that we looked at and it is both from closure from air and water of the
life support system, miniaturization of the system and the low consumable footprint that
with respect to other things also, that you have to have a system that you don't have to
bring tons and tons of the replacement parts up there to keep things running.
We noted as a group that there is a lot of good work ongoing under HRP and suggested that
would be worth while continuing.
I thought I removed this page but I obviously didn't.
Let me see my comment.
Just as a comment in final that we did not look at the other parts of the mission.
There are a set of capabilities and technologies that are needed associated with other
phases of the mission.
This is just the on-sight portion but the sense that the human system side was a very
important piece in that we had looked, thought about at the beginning of thinking about
the capabilities needed from a sense that we do deep space missions already but what's
different about the fact that you now have humans on board, or likewise we do humans in
low earth orbit and have done to the Moon what's different about taking humans farther
than where we've taken them before.
Those were some of our guiding thoughts to make sure we were trying to capture the range
of activities.
That's what we have.
Olson: Okay.
Wonderful job.
Now we'll open it up for questions for the next 10 minutes.
And, I remind you, I guess you didn't hear that the first time.
We'll now open it up for questions for the next 10 minutes and, thank you, Clive, we
would like folks to use the microphones so that the web audience can hear loud and clear.
Neal: You've turned it off on purpose.
[LAUGHTER] Clive Neal, University of Notre Dame, Midwest Boy.
Just a question with regards to the technology session.
Did anything come up with regards with the feed forward aspect, making the technology
applicable to multiple destinations rather than just being for a NEO so if the ultimate
goal is to go to Mars, is there going to be flexibility in some of these systems, did you
discuss what would need to be unique and then what could be carried on to other
destinations?
Wilson: I will make a comment first but I will leave the opportunity for either of the
facilitators to respond too because by definition I heard less than a third, most half of
either one of the conversations at the two tables.
We didn't talk specifically about synergy at all since there's another panel that's
specifically addressing that.
The only aspect that I was aware of that we talked about that was feet-forward is the
sense that all of these activities are taking space in deep space and so the whole
question of reliability, repair, robustness, autonomy, are all things that obviously
carry forward into any mission and are going to be even more important for missions that
are longer than this one.
Answer: In particular, the table that I was at had more discussion on mission duration
and how that relates to the technologies required rather than anything that was
specifically a destination-dependent issue because the synergies group was more or less
assumed to be addressing that.
But there was considerable discussion on the mission duration and how that affects what
you do and not limiting our technologies for being specifically a six-month NEO mission
and that's it.
So there was some discussion of feed forward but not necessarily how it manifested
itself.
Neal: Thank you.
Question: One are the key Level Zero objectives that our group came up yesterday was the
establishment of an affordable transportation architecture and so I'm wondering, I didn't
see any technologies relevant to in space propulsion, for instance, that could reduce the
cost of the mission.
Answer: Actually my group talked about that in addition to the instructions that we were
given is that we had decided to, because we only had two hours, to only focus our work on
once you got into the vicinity of the NEO so how you got there was assumed to be a piece
of work that needed to be done by someone else and so the in space propulsion as it
related to getting from Earth-Moon vicinity to a NEO vicinity was something we chose not
to address at my table.
Answer: Yes, that's right.
We just assumed there would be some in space propulsion system available.
The only aspect we talked about was maybe we could use the electric propulsion system
once it's arrived to the NEO to supply power for surface operations so maybe we could
beam power down to the surface that was generated by the solar rays on the SAP system.
Question: Great.
As long as you guys recognize that there is a big technology gap there.
All: Absolutely.
Sander: Mike Sander, JPL.
So, one of the things that you touched on was this notion of logistics and I'm just
wondering if there were any specifics with respect to, and it could be judged as really
an architectural issue as well, making sure that there wasn't one particular car designed
for every single function but rather taking a look at the architecture of the system
design to minimize the number of different designs that were incorporated into the system
so that there would be reuse or possible or interchange of functionality from one system
to another.
That's a fairly profound thing that we collectively, in the business, haven't done a very
good job on.
Answer: My table had a fairly lengthy and exhaustive discussion on that because it came
up a couple times.
It came up in terms of dissimilar redundancy of any one particular system but also in the
sweet of systems that are required for space flight in general, we talked about multiple
independent systems but that have some level of common components that are
interchangeable, so instead of large LOU pull-out push-in kind of methodology that you
can actually just swap boards and think about your logistics train as a philosophy of
sparing a philosophy of architecture and a philosophy of logistics and that those things
have to be related.
Question: Since you focused on your time at a NEO, can you elaborate on how you got to
the need for closed-loop life support because we did habitat studies for the moon and
thirty days was a break point.
Answer: It was because of the assumed mission duration and the feed forward aspects of
the mission.
We didn't assume only the time that you were at the NEO but we did not describe heavy
lift launch vehicles and the space craft that gets you from Earth-Moon vicinity to NEO
vicinity even though that we know that those have to exist because though are
sufficiently complex to deserve their own independent study.
Question: That makes sense.
Thank you.
Olson: I've got a piggy-back question on that one.
Essentially, in looking at the closed loop versus the robustness and reliability was one
deemed to be a higher fidelity factor?
You mention both but was one more of a driver?
Answer: Reliability was more of a driver given mission duration and out of consumables
that we have to carry with us was relatively small.
If we go to longer duration missions, the closed loop becomes more important.
It's essential that we have reliable systems to keep the crew alive.
Olson: And one follow-on question was you talked about drilling or injection-type kinetic
attachment, did you look at anything non kinetic like nets, blankets, barges, adhesives,
freezing, crampons, that type?
Answer: We didn't have a lengthy discussion.
We're all aware of the variety of options and I think the sense was those options need to
be looked at and understood.
Which ones may work for which type of body?
I think we were real clear that in many cases there are approaches that are thought to be
relatively well in hand for anchoring but which one you would want to use would depend
very much on the nature of the body so the understanding was to both look at things that
could work for a variety of ranges but also to decide which to be ready for any of them
was important.
Answer: When we categorize things it was 'is there a suite of solutions that we know
exist and all we have to do is do the design development and test, not necessarily create
a new kind of thing.' So, most of those items were bucketed in the do some design
development test on a wide variety of techniques rather than create a new technique from
whole cloth.
Olson: Thank you very much.
I'd like to say thanks a lot to this panel and we'll bring up the next one which is the
Concept of Operations with Doug Craig and his team of facilitators.
[APPLUASE] Craig: Thank you, John.
Before we get into the presentation, I want to say that we had a lot of good
conversations and trying to pack the discussions of concept of operations for a mission
to a NEO in a couple hours was tough.
If we had a little bit more time we could have probably gone a bit further and maybe even
made some videos for you, John, but we didn't have that opportunity to do that for you.
[LAUGHTER] But we did come up with some really good ideas as well as some issues for
future analysis so with that, we started with the day one results, as Marguerite had
briefed out this morning and then looking at that we wanted to figure out what were the
concepts of operations and how should the humans interact with the NEOs and what we
decided to do was break it up into phases, the mission phases.
We wanted to focus on the what you do at the NEO phase first but we also knew that you
had time both in transit to and from the NEO that we could take advantage of, in fact we
should take advantage of so we wanted to include that as well as the low earth orbit in
preparation and we took a stab at all of those.
And then what you'll see is we put the presentation together into the more temporal
aspect of going from LEO and then transit to LEO and therefore, but you see, we focused a
lot more at the NEO.
So, the concept of operations at low Earth orbit, we figured this is where you would do
the assembly and check out of the expiration systems and some of the systems that we got
that required at the NEO were core module, which had your power, logistics,, your ECLSS
system, you'll see in some other charts like the 'Mother Ship' with that and the
propulsion stages.
We looked at having one to two excursion vehicles, or space exploration vehicles, you saw
the SEV and then some return vehicles, you saw the return vehicles as part of the Mother
Ship so you can return safely, and then, I'll get into this on the next chart but we
really looked at the advanced recon probe and this was brought up in the robotic
precursors, so while we're going to get a lot of good information from the robotic
precursors.
We may have a launch slip and so if you did we wanted to make sure that if we slipped the
launch for one NEO we could probably have alternative NEO to go to so we want to be able
to send an advance recon probe out to get information to bring back to us to do future
planning.
And then also we get into provisioning, basically we're getting the logistics up there as
well as the humans.
So an outbound to the NEO, the operations I talked about this probe for advance recon,
you want to send it out, it's got to be simple, it's got to be small, whether it stops at
the NEO or just keeps going by, we would have to do some analysis on it.
But we would like to have it out there weeks to months prior to the crew so that we could
get the information back to identify the physical characteristics of the NEO, the size,
the spin the composition maybe some local features and this allows for the NEO
modifications, if we have a launch contingency issue.
The other thing that came out, we had a lot of time during the in-flight mission and we'd
like to keep the proficiency up and make sure that the systems are being tested so we do
a lot of in-flight training.
One of the ideas was to have a simulated NEO surface as part of the ship's going out and
what you could do is you could take your excursion vehicles and practice the NEO
operations that rendezvous and docking, practice your EVAs; you need your EVAs for
contingency as well, so we have that.
Another idea was to do some simulations, to have on-board simulations so that you could
do in-flight training with as well.
Once you got the information back from the recon probe, you would refine the flight plans
prior to the arrival to the NEO and then you would incorporate that into the training and
the simulation as well.
The other important part is systems monitoring and you're going to see this around all
phases and one of the objectives of course is to feed forward to other destinations and
so it's important to monitor the systems, not only for just the failures but also the
performance so you can have that information for future missions.
And then while we're, we have time to be able to do other opportunistic research such as
microgravity biological research, look in variable gravity or radiation monitoring, do
psychological or physiological research while we're on the mission.
One of the things that we think is important is to keep the crew engaged during the
mission, especially the long duration outbound flight.
It's important to keep them busy so that they continue to be motivated for psychological
factors.
When you go out to a NEO you can have the outbound leg the long duration with the return
the short duration or vice versa and we got into a conversation about that, 'what would
be better?' On the one hand if you had the outbound short duration then the crew is more
fresh when they get to the NEO and then when they are returning they can do things like
sample triage.
But our group thought that the most important thing would be to have a long duration leg
up front of the outbound so they could do the training and get ready for it plus from a
safety standpoint you have a safer return coming back for the NEO.
So now we get at the NEO.
We put a lot of the ideas up and they kind of gravitated toward one of four areas.
Basically operations involving human space craft or EVA Ops, Science Ops and Robotic Ops
and I'll get into each one of those coming up.
So, human space craft operation the first thing you would do once you get to the NEO you
would do far and near field surveys obtaining the situational awareness, ground truthing
the information you got from the precursor missions and the robotic crow.
Looking at the hazard characteristics and then make sure that you could tweak your
operational plans as required.
And you also do the resource assessment in making sure that you accurately picked the
sites of interest that you wanted to go to at the NEO.
Then the next phase of operations would be an orbit insertion and station keeping of the
stack, if you would, and one of the things that we thought was important that the stacks
stay off the NEO surface just due to safety factors so we basically came with the idea of
having some sort of excursion or exploration vehicle that would go from the mother ship
down to the NEO and then the astronauts would use that for their EVA activities.
The analogy was given; think about when you're exploring the Titanic.
You don't have the ship up on the surface and you just send the divers down.
You actually have an excursion robotic craft to go down to the surface and if you could
have divers then you could have them go out of that ship rather than the long traverse
from the EVA standpoint.
The exploration vehicles would go down and somehow rendezvous and dock with the NEO if
appropriate.
First you'd want to anchor somehow, there was a discussion should you anchor or not?
We had some debate about that, do you want them free flying or do you want to anchor and
after a long discussion it was determined the best thing to do would be to anchor there
but if you couldn't do that then you'd basically station keep doing free flying.
We looked at different things like laying a cable grid for translation of the system, so
basically you could anchor several points and have the excursion vehicle translate on the
grid, so that was one of the concepts that came up.
Another thing that we need to look at is that we want to make sure we don't kick up dust
too much and so that's going to be a big factor in this because if you go there and you
pick up a cloud of dust with the microgravity there you could end up having a dust cloud
for the 14 days you're there and it kind of messes up your operation so we need to take
that into account.
We monitor the space craft system's performance and then you have the return back to the
mother ship when you were done exploring with the NEO.
So, the EVA ops, so once the excursion vehicle or exploration vehicle is down to the NEO
the astronaut would get out using a suit port idea to EVA to the surface.
We thought it was very important that the astronaut fix to the NEO or to the exploration
vehicle so that they didn't float away and also for other safety reasons.
One of the things as we were looking at doing was some sort of translation system to help
move the astronaut around and you could either do it like we do on station with a robotic
arm and have the robotic arm move the astronaut to different sites of the NEO or we could
have the excursion lines where we'd lay out excursion lines across the NEO and then the
astronaut going EVA would attach himself to the excursion lines and then we could have a
cable grid which is pretty similar.
Now, one of the other discussions we had was how many crew is required for this and we
were thinking that from a safety standpoint, a minimum EVA team would be two and we'd
always want to have at least one person in another vehicle for rescue purposes so we were
debating whether the crew size should be three or four but definitely more than two, and
that is to do the IVA monitoring not only for rescuing but it also enables a little bit
better situation awareness, if you have someone standing off and being able to look and
monitor the big picture while the EVA team is out.
For Science Ops one of the things that we came up with was basically we should have the
EVA crew do the majority of the science task but you'd have the robotic assistance.
So, for instance, in the core sampling or deep drilling you'd have the astronaut go out
there and identify the spot to drill help set up the drilling system but then you may
leave that system there to do the drilling while the astronaut, if it takes five to seven
hours to drill a core sample, it's not the best use of the astronauts time so they could
go off and do other things.
Other Science Ops were setting up surveys for seismic research, sample collection; we got
into a little bit of a discussion on this.
Do you just sample small samples or can you look at accruing a bulk sample and then using
that bulk sample as a way, what you'd do is you would analyze that on the return to Earth
phase of the mission.
Also looking at ISRU demos, not only are they for ISRU but also for the characterization
of the chemicals and volatiles on the NEO.
The other thing that we would have the EVA crew do is deploy an emplacement of packages,
we talked about the seismic sensors or the tracking devices to validate your tracking
models for the NEOs as well as any orbital modification techniques that we were looking
at, whether they be the low impulse or the detonations so the crew would do that but we'd
also have some robotic operations prior to the, during and after the EVA.
We're looking at having some kind of situational awareness capability using free-flying
robotic system that could give people a better vantage point of what was going on.
Like I was talking about autonomous drilling and then you might want to leave some ISRU
equipment behind to let it continue to run until you build up testing time for it while
you leave.
We also looked at leaving behind the robotic assets, something like the exploration
vehicle if you could so they could continue until the operation and communications as
well as you could use it for public engagement.
So, return to Earth, we kind of mentioned this but basically we have a lot of time going
back to Earth so we though the most valuable use of the time for the astronauts while at
the NEO is collecting the samples and then you would take the samples back and then you
would high grade them and curate the samples on the return, you could also continue to
operate, monitor the systems that were left behind as well as looking at the planetary
defense experience such as a NEO impactor and also continue to monitor the crews
psychological and physiological activities.
So, that is it.
Thank you.
[APPLAUSE] Olson: Excellent job, you covered the full spectrum of the Con Ops phases
there so we'll open it up.
Again we've got Mike Gerhardt and we've got John Connolly here as well who helped as the
facilitator so, first up.
Morrison: David Morrison here.
You seem to be satisfied with having the robotic precursor launched in the same
opportunity and just get there a few weeks before which seems a little different from
some of the other assumptions.
Did you talk about that much?
Answer: We talked a little bit about it but not into much detail.
But, the idea would be that the robotic precursor would provide us with more information
on the number of the different types of NEOs and give us that information that we could
then use for this advance probe.
Answer: So obviously we'd like to have a precursor of the exact asteroid that we are
going to and have all of that information but the notion here is that you slipped your
launch and you ended up going to a secondary target, this provides you a way to get some
insight to refine your flight plan on your way out.
Sanders: Jerry Sanders, Johnson Space Center.
In our synergy group we talk a little bit about EVAs and one of them that came up in our
discussion was the fact that because of the dust and kicking up plume impingement and
stuff, one of the approaches might be that we would do most things with robotic assets
near real time with the astronauts there and that the astronauts are used for contingency
or problem-solving aspects.
I saw, and your charts almost the opposite where the bulk of the activities were
EVA-related, so I just wanted to throw out the pros and cons and have you guys respond
with that.
Answer: I'll start.
Jerry, we had that same conversation in our group.
Our thought was that the reason we are sending humans to a NEO is to put scientific hands
and minds as close to the subject matter as we can so we tended to go more towards the
idea that scientists doing EVAs is really what you're there for so we tended to load
everything that way rather than robotics.
Robotics is certainly important but we thought that the EVA experience was really the
whole point in going there.
Answer: But I think it's important to point out that we have other robotic assets that we
talked about using and we would use our judgment.
For example, if there were parts of the asteroid that we would anchor to then the SEV
would be anchored there, the crew would be attached to the SEV, we could deploy the
drilling and seismic equipment without stirring up dust.
If there were other areas that were particularly dusty and interesting we could use a
different combination of assets and so the key thing as John pointed out was to really
use the humans for what they're best at but certainly some judgment goes along with that.
If it turns out the whole thing, you're just stirring up dust; you probably don't want to
do that.
Shears: Dan Shears from the University of Colorado.
I think it's very exciting the things that you're talking about and I can't wait until
something like this happens.
One thing that I have a slight worry about is that you seem to make a lot of assumptions
about your ability to couple with the surface with the asteroid and this is an aspect of
asteroids, especially the smaller guys that we would probably go to that we really don't
understand and I think it would be good to have or try to relax that assumption in the
works that you do to see if there are solutions, which I think there are, that wouldn't
necessarily rely on the ability to couple strongly to the surface of a small guy like
this.
Answer: And we did have a lot of discussion about that and we said it would be preferable
if we could.
But having said that, the fall back plan that we think would work on almost any asteroid
would be to station keep in the exploration vehicle and then have an arm that would
position the astronaut and the much the same way we do space walks on space station, you
could move the astronaut around to do the various sample collection and instrument
deploys.
So that would be the fall back plan and that's an integral part of the capability.
Answer: and one of the reasons why we'd want to attach it is so we wouldn't have to carry
as much propellant for the free flying translations and station keeping aspect so it
would help the architecture in general if we could dock to it.
Question: The delta V you need to hover aren't that big but, okay.
Thanks.
Question: Just an observation about sampling and processing and science on sample on the
way back.
Number one, from a safety point of view I think the last you'd really want to do is have
the crew handling the samples coming back unless you have fairly elaborate glove box
system which would be kind of heavy and expensive and, if you drop the glove box you'd
have plenty of fuel for hovering them, plenty more mass for fuel.
The other thing is your high precision sample team back on Earth, the last thing they
want to do is have people is handling that sample before they get to it because you're
changing the environment and the chemical environment enormously, when you bring that
sample off of a highly oxygen-starved asteroid surface and bring it into an
oxygen-poisoned, water saturated capsule with a bunch of sweaty humans, unless you have a
really elaborate glove box system, you're going to have problems.
Answer: Actually the glove box systems is one of the things we would want to have and the
bottom line is it's true, you don't want to handle all of the samples, but it's also true
that we only have certain capabilities to return the samples to the surface of the Earth
and so you'd want to be able to triage with the scientists on earth as you're returning
to the Earth to figure out what samples are the best ones to bring back.
Question: if I had the choice between triaging a bunch of samples in a 50 kilo glove box
I'd say dump the glove box out and take 50 kilos of samples.
Answer: We had a lot of discussion here and that's interesting input and we're wide open
to the right way to do it.
But, the thought was it's certainly not a good use of crew time, while you're only there
for two weeks, to do all of this high-grading, and the thought was if we could grab a
whole bunch of samples, and we talked about everything from glove boxes to actually a
nitrogen pressurized inflatable area with cameras and so forth and the thought was to use
that long trip home to really work with the science team on the ground to figure out the
ones to bring home.
Question: You're not going to be able to haul the ion probe with you and that's what the
team on the ground's going to want to do.
The other thing is the objects are much likely to be monomineralic, that is, that you're
going to have a single compositional type.
Dunsten: Jim Dunsten.
This is kind of a follow-on to that question.
Was there any notional concept of how much you would be bringing back in terms of sample,
are we talking about an Apollo type sample or are you really talking about lopping off a
big chunk and then bringing it back and studying it along the way, just in terms of maybe
even a percentage of in-bound mass of the whole system.
Answer: We talked about a wide range, and all these are just ideas, but one thought is if
we had two very small Earth return vehicles, each one would be capable of bringing the
crew back.
But all of the living and exercise and EVA robotics, all that's in the space exploration
vehicle and we have these redundant Earth return vehicles and if they both work, we could
load one of them full of samples instead of giving you 100 pounds or something small like
that, there's a potential to bring quite a bit more back.
Answer: I think we'd look to the science community to advise us on the right quantity of
samples to bring back was and I'm sure Clive Neal has some opinion about that.
Neal: Yes, I do.
With regard, if we look back to the lunar activities that went on, initially we heard
that 100 kilos had been allotted for sample mass and that's total mass including boxes
and everything else.
So, the curation and analysis planning team for extraterrestrial materials did a study to
look at the amount of mass that would be required to address the science goals and it
came out to be substantially more than that and I would urge that in the planning for
this, that samples just don't get an arbitrary number of 100 kilos to bring back because
it's the samples that are going to feed science way into the future.
Now, for ESMD that may not be a big driver but it's going to tell you an awful lot about
your NEO and also it's going to add a lot of credibility or more status to the remotely
sense data, so now you have ground truth, yes, we've got meteorites but now you have
actual ground truth in that space weathering environment that is going to effect the
remotely sensed data.
So the more samples you can bring, you have to maximize the sample return and I think
that these options need to be weighed very carefully rather than just given an arbitrary
mass which may not be adequate.
Question: Is it always that more is better or ...
Neal: It's always!
But, there are ways to approach how much more and to quantify that and I think that this
needs to be passed up maybe to captain to, I don't know but to a sample handling group
that can look at this and bring in the expertise as needed to address this question right
up front so the mistake that was made with the lunar launch vehicle or the return vehicle
is not made here.
Question: Do you have any thoughts on the utility and/or the specifics of how you might
high grade samples on the way back?
Neal: Again, a lot of work was done with the Moon about having the habitat, the lab in
the hab, and what you would do and there was never really a consensus among the community
but simple is better.
You would think of doing field geology on Earth, you high grade your samples when you're
going over a terrain.
Simple is better.
It depends, what are your science objectives?
What are you trying to do with the samples?
What are you trying to prove?
And until we address that question, you know what type of sample to bring back, then it
starts to give you a way forward.
So, again, my opinion is that you can do it very simply but we've got to learn from
Apollo, there was a rusty rock that came back because it was exposed to the atmosphere of
the return vehicle and it caused changes and this does happen, it was done in Apollo and
Dan's right, we don't want to expose them to a crew vehicle atmosphere.
Olson: Chris, did you have a follow-up to that or is it a different question.
Chris: Clive was on a very important tract here.
This discussion is an architectural nature discussion.
If you don't want to get into the same boat that Constellation got into, you have to have
made some assessment and decisions about the amount of mass you're reaching back to, all
the way to Earth, very early in the architecture stage because if you don't you're
limited by the physics of the return vehicle itself.
That's what Orion got itself into.
It had nothing to do with what we wanted to do with the samples, it had everything to do
with how much mass they could afford to bring back under parachutes.
So you've got to make these decisions very early in the architecture.
Mike was going in the right direction, too.
If you only have two return vehicles and you get a lot of return mass, that's fine, but
it completely changes every other element of your architecture so you could push that
huge chunk of stuff all the way out there and back again.
Answer: if you could aero-capture and leave some samples in LEO and if you ever wanted to
go back, you could get there and look at them more.
Peter: Just a Con Ops and architecture consideration I wanted to throw in, you know there
are several things that we think about wanting there that are quite massive and in some
sense also just nice to have, the glove box, certain types of drilling, perhaps something
in the nature of ISRU or mass driver.
That doesn't necessarily have to go in the same space craft as the crew and if you had a
concept in your precursor mission to have some kind of prepositioning, you might be able
to use a solar electric propulsion to take it and have it there ready and if it didn't
work it's no great loss.
But then you have that solar electric propulsion tug there that could then take back
samples and returns and might in fact have its own little air capture or return to
atmosphere or perhaps you could just leave it in LEO for the space station to look at but
the idea of prepositioning and a separate trip back from the crew, I think it's worth
consideration.
Answer: That's an interesting thought and it certainly parallels some of the
constellation with the cargo landers and things of that nature.
Olson: Good forward work topic.
Answer: What you're talking about there is a form of NEO orbit rendezvous mission, even
though the crew, part of it all comes out on one big tug, you have something
pre-positioned so you're Ops Con is that you're primarily putting the big stuff together
in low Earth Orbit and heading out with the crew but your prepositioning something, doing
essentially a NEO rendezvous so it's kind of a combination mission.
It's not a bad idea.
Olson: Affirmative.
Last one, Dallas.
You've got a lightening round.
Dallas: Back to the mass quantity.
I believe more is better but going back to Apollo, how much did we bring back, how much
did we actually assess and how much have we distributed out of what we brought back 40
years later?
Answer: That's a great question.
[LAUGHTER] I'm sure someone in this room who knows that and Eileen is coming to the
microphone.
Eileen: We have quite a few samples brought back from Apollo and all of the samples have
been characterized in one to one level or another.
The real issue is being able to find the right set and the right portions of a sample
within any return and so we still have on the order of 300 samples allocated every year,
40 years hence, so you do have long-term value of any of the samples you bring back.
There is nothing that was brought back from Apollo that was not priceless and highly
scientifically satisfying.
There are some subsets that are more valuable than others depending upon which portion of
the scientific field you're interested in and so saying that you don't need to bring
samples back or you want to arbitrarily limit the amount of sample because we have not
used all the 800 kg we brought back from Apollo is not a scientifically valuable
discussion to have without having representatives from a wide diversity of disciplines
aiding that discussion.
Olson: Okay.
Thank you very much.
A round of applause for the Con Ops group.
[APPLAUSE] Good stuff, next up we have the Planetary Defense sub group lead by Lindley
Johnson and his team.
So, Lindley, come on up to the podium and we'll dive right into it.
And, following Lindley's and the open 15 minute discussion period, we'll have a break
after that and come into the final two.
Johnson: okay, well I want to start off by thanking both my two facilitators, Bill Ailor
and Pete Garretson.
They did a wonderful job.
And the two scribes for the panel, Stratus Kotaculus and if I didn't pronounce it right
that's the way it should be because that's a fantastic name!
[LAUGHTER] and Barry Epstein.
I would especially like to thank my facilitators because the first thing they had to help
me do was put down a near mutiny because our break out session really wanted to talk
about the precursor mission because we see a lot of benefit in the precursor mission.
So, in order to prevent a hostile take-over of Jay Jenkins' break-out group [LAUGHTER] we
came up with this slide here to make a strong statement that we really see a lot of
synergy between the planetary defense mission and the human mission and survey and
characterization of the NEOs during the precursor missions.
If nothing else, this may be the most important benefit to the planetary defense mission,
is the work that's done by the precursor missions, hopefully for both human exploration
and planetary defense.
So, after we got that behind us, we then went into two segments of our discussions and
the first one was to talk about what over arching insights and activities would be
important to planetary defense during the human mission to an NEO to help further flesh
out some of the objectives for the human mission.
So, the top of our list is testing to help add detail and understanding of various
planetary defense capabilities.
Of course the human there can do a lot of things with the test equipment, first of all to
make it work if there's a failure, if it's not working right, but also to use the
equipment in various different ways, some of which may not have been thought of before
getting to the NEO itself.
So, we see a lot of benefit there.
So, that kind of goes along with the ability reduce the risk and failures, sort of risk
mitigation of planetary defense testing.
I think there are a lot of lessons that can be learned from the Hubble repair missions
and the type of improvisation that was done during those missions for work at the NEO.
That last bullet is along those same lines, 'the ability for the human crew to synthesize
and adapt based on what they observe and experience in the initial days at the NEO.' We
see the mission and the endeavor to go to an NEO as a great confidence builder for
campaign of operations for planetary defense, we will gain a lot of knowledge, expertise
and experience in such an endeavor.
The testing that can be done at the NEO will do a lot to increase our confidence of some
of the proposed planetary defense techniques and capabilities, for instance, impact
effects, the so called beta factor that, I don't want to go into the technical detail of
that but there are certainly unknowns to understand a lot better before we have to
conduct a real world planetary defense mitigation activity.
Some of these techniques do require attaching things to the surface so testing and
experimentation with surface attachment concepts and equipment would be an important
activity.
Precise anchoring placement of things like explosives or disruptors, how that would be
done to test how it would be done in a real situation, whether it be humans, which we
find kind of doubtful, but testing of the techniques and later being used by robotic
space craft.
You're starting to see here there's actually a lot of overlap and redundancy of what
you've seen with some of the other groups in talking about surface activities, anchoring
of things, attachment surface operations.
Here's another one, testing of autonomous train relative navigation systems either for
use in a gravity tractor or something that might need to be landed on the object for the
mitigation technique.
Also, testing of ways to rapidly develop the gravity model, testing a different modeling
techniques, to get the gravity model in a matter of hours if at all possible.
I don't know exactly how that will be done but it would great if it could be.
Then in looking in areas of engaging the public, public awareness, keeping the public
base and support, to these endeavors, a mission to an NEO would certainly increase the
public visibility of the whole enterprise and aid in their understanding of what these
NEOs are and why they can present a threat to the Earth, an impact hazard to the Earth so
being able to sustain human interest during an NEO mission, there might be an advantage
there to doing just robotic testing of planetary defense techniques and activities that
additional brought in by humans at NEO could be a benefit to the planetary defense
mission.
Then, of course, international participation, having it be an international mission with
an international crew helps to build confidence in the type of international decision
making that's going to have to take place should we get into a actual mitigation scenario
where it might, we're still working with the international community as to how decision
making might be done and sort it out but it's obviously got to be a multi-nation effort
to decide if the Earth is going to be impacted by an object.
Who's going to do what when to mitigate that and there are certainly discussions within
the United Nations, particularly in the committee on peaceful uses of outer space on that
kind of regime and protocol.
So, we see the benefits from this activity, mission activity to help us out in those
areas.
And then when went into looking specifically what tools the human crew might take with
them, tools or techniques that the human crew might take with them to test specific
mitigation techniques and we have a whole list of those things that are roughly divided
into two major categories, either something that is a rapid impulse, give a punch to the
object to change its velocity vector enough so that it is deflected from an Earth impact
trajectory, so the first one of those, and these are not in priority order or in order of
what we think is feasible or not or we'd be most effectively, but just to get them on the
deck here.
The first one we talked about is surface explosive, just a conventional explosive on the
surface to give it a little bit of push and so you need to look at attachment techniques,
how that device would be anchored to the surface and then what kind of explosive devices
might be used and most effective.
Now, I have to caveat all of this to say that our break-out group were not expert were
not experts in crew safety [LAUGHTER] for the mission so we didn't try to do any kind of
dividing out here as to what crew might be allowed to do or want to do, just things that
might provide important and significant information to these mitigation techniques.
Another technique is a subsurface explosive that actually blows off a considerable amount
of material from the object to effect a course change or, if it's a small enough object
and a big enough explosive, it would completely disrupt it, there are advantages and
disadvantages to that technique but it is a technique that is discussed.
So looking at penetrators, some kind of penetration gun, seismometers to understand the
structure of the object so you know what are the best places to put the explosives, for
instance, to better disrupt the object, things as simple as digging a hole, what does it
really take to do that and keep it open and to put explosives into.
Drilling, you've already seen a lot of talk about drilling devices and how they anchor
and operate them.
And again, small explosives to get those effects.
Some of the other leading candidates for mitigation techniques, the Kinetic Energy
Impactor is certainly a good one since you've already seen one work, at least to impact a
small body, whether it really would do the velocity change or not, theoretically it makes
good sense but they might want to do some testing of that so the use of a hyper-velocity
gun to get a little better idea of what the effects might be and , again, majoring this
beta factor, when you impact one of these objects, it causes an ejector to come and the
beta factor is how much that ejector multiplies the overall force than just the impactor
and that's what the beta factor is so there's an unknown, that may be only one or as much
as ten times, so, planning out what the variation of what that is for various types of
objects is an important thing.
Again, seismic measurements, measurement of mass is always an important thing, it's one
of the important things we've got to know with mitigation technique, how much mass are we
dealing with.
And then there's one that we hope we never have to use but if we get into a near-term
impact threat and, particularly if it's large, a nuclear device or physics device
selected to [INAUDIBLE], it would be our last ditch capability so measurement of the
surface characteristics again, how that works is you blow off a lot of material causing a
deflection so measuring all these characteristics of the surface down to about half a
meter is important in measurement of the mass.
Let's go into some of the slow push techniques.
We've got about three or four of these.
Oblation techniques, again, to use something to blow off mass, to change the vector, so
using laser to do that is one of the ideas or small u se of a laser to show oblation and
how it works, how much mass in measuring, how much mass might be taken off is a good
experiment.
Using a mirror to focus sunlight, seeing what the effect is of that and then measurement,
as I said, how much mass is taken off and what the velocity of that [INAUDIBLE] caused by
those things.
Enhanced natural effects, these are the ideas of, you let the sun, solar energy, really
let the sun do the work for you, if you change the surface of the object it's Albedo so
how much, changing how much solar energy the object absorbs versus what it reflects, that
over time can have a significant effect on the objects orbit particularly if it's a small
object.
So we might do a campaign here of if you get good measurements of the Albedo before you
get to the object and then perhaps at the end of the mission the crew does something to
change that on the surface of the object, it could be something as simple as scuffing it
up with your boots or take some garden tools along and just rake the surface of the
object to change the brightness of the object, rock gardens, it brings a whole new
concept to rock gardens, doesn't it?
[LAUGHTER] After the crew has left you continue to track the object after the mission
after the effect is.
Gravity tractor placement precision transponder, precision lidar and radar, testing of
those techniques and autonomous operations and navigation for something that might
actually be a robotic device when you get to a natural scenario.
Attaching thrusters, we don't think this is a real viable concept because rotating
object, you couldn't have continuous thrust but, attachment of devices, things like a
large solar sail or attitude control of those devices and also what the effect of the
dust environment that might be kicked up would be.
Lastly, one we think is probably the most, at least unknown if not effective is things
about the mass driver.
With that, we also wanted to do the Operations Concept's jobs for them [LAUGHTER] and I
don't know if you can see this very well but Peter is excellent in putting together Ops
Concepts so he's got a little cartoon that he'd like to talk through for about, what have
you got, three minutes?
Garretson: It's always difficult to be the one military pilot in the room full of rocket
scientists so I have to try and reduce it to simple stick figures that my mind can
understand.
But actually, in terms of trying look at what would be a synergistic Con Ops as it
relates to planetary defense, this is kind of how it would look.
On the left side you have a telescope that becomes the survey but you're looking for
targets that has great synergies because in terms of the actual planetary defense, that's
a huge take-away.
That of course establishes the target, then the next phase is to send a pre-cursor
mission which captures the morphology, the spectroscopy gives you an idea of the surface
characteristics and perhaps another precursor that prepositions some amount of equipment.
At the end of that you have a well-characterized, what does it look like, something you
could post on Google Earth, something that people could get a sense.
The next phase, the man portion of the mission to come.
At the top you can see they instrumented out, they drill core samples, they put the
reflector or the transponder there and the conclusion of that phase now you see the next,
you have idea of the interior structure, the micro/micro-precocity of it, what its
internal structure looks like.
Then you have the crew start to look at tools so they look at the potential mitigation
options and I've sort of drawn out here, you bury an explosive, you have light
concentrated to do some boiling off gassing, you have your ship try to orbit it at one
radius to see if your autonomous gravity tractor software works and if you can detect a
change, if you've got the technology and it's not, you might try something with a mass
driver or a hyper velocity pellet.
And then at the conclusion of that you move away to a distance that, if there is a
distance, that's safe for something more dangerous, now you attempt to take a look and
observe an impactor.
An impactor comes, throws off the eject and throws off the crater then you either
telerobotically or with your, people go back, try to get deeper core samples, leave
behind a fully instrumented asteroid that can be tracked, and of course you take your
samples home in either your space craft or in the precursor prepositioning thing that
came there.
Now, what is the synergistic take-aways for planetary defense of having stepped through
this.
Well, you complete the 140 m congressionally tasked survey, or down to 140 m.
If you've done the precursor mission right, you have an off the shelf advance recon probe
or tagger tracker that you can actually apply, pull off the shelf toward any real threat.
If you've actually done the impactor then you have an off the shelf interceptor, you have
at least one tested tool for a kinetic impact that you can through against it.
You say I've taken this to a usable TRL and then that same impactor, if you construct it
in such a way that the seeker guidance fusing casing and everything would allow for an
explosive internal package, you've done most of the work to get you to a second
capability that you could throw it against.
Then you characterized a significant amount of information for planetary defense mission
planning in terms of orbital deflect, orbital dynamics and planning, modeling for
mitigation techniques in the kinetic impact surface, subsurface, explosive gravity
tractor and light oblation, you've advanced those in TRL and workability and your
confidence in those and so you've in effect gotten yourself two tools that you can
actually apply plus the survey and the potential mission stuff.
There was one thing that I thought I would bring up is that if you're actually thinking
of trying to move an object, particularly one that is on a potentially hazardous list,
there are going to be a lot of people that are going to ask, 'well, is it possible that
you're making the problem worse?' So I think in that in case, the easiest case, if you
can find it, is to do that on a totally interior object where you could very easily
explain to the public that this is inside the orbit of the Earth.
Anything we do to it is just going to move it closer to the sun so there's no problem
with that.
Olson: Okay, thank you very much.
In the interest of time, we will open it up for questions however we'll have a shorter
session.
So we'll look for 10 minutes or so of questions.
Question: Tethered satellite was a great example of a demonstration of a linear momentum
exchange using tethers.
Did you guys look at the possibility of using tethers and then cutting the tether?
Johnson: That idea has come up in terms of planetary defense.
We did not discuss it here today.
It has been talked about though and we've had planetary defense conferences, three of
them now over the years, and it's been talked about there but it was not talked about
today.
Question: It proved to be very efficient on tethered satellite so it might be something
worth looking at.
Answer: There are some papers that are published on that topic so that would be something
we could use for reference.
Chapman: Clark Chapman, Southwest Research Institute.
And this is mostly about Lindley's presentation rather than Peter's.
It struck me, although you have a long list of deflection techniques that indeed have
been discussed, I think most of the analyses have centered on three and it seems to me
that they're kind of disjoint in the following sense.
Kinetic impactor, we'd like to determine beta, but when you're on a rendezvous mission
with human beings there, you've got zero delta V and it just seems like kind of the wrong
kind of mission to be testing the explosive reaction.
Now, if you want to bring explosives or hyper velocity guns along in a space craft which
I'm not so sure about but I'm not an engineer[LAUGHTER], you're nonetheless operating on
the body at a very much smaller scale then what you would do in reality.
Another one is the gravity tractor and that is a device that really doesn't care about
what the surface is like, it's just the relative mass with a spacecraft and an asteroid
and the third one, the nuclear device, is one that's really applicable to NEOs that are
at least half a kilometer or maybe a kilometer in size and larger, so the kind of body
we're likely to visit is much, much smaller and may not be representative at all of the
response of the larger body that you use a nuclear device on.
Johnson: Copy all that.
We understand that, well at least a lot of us were talking about it but I think
regardless of the size object to go to and the effect that's used, that there certainly
are useful things that can be tested by human crew.
Answer: Just to add to that, on the kinetic impact, the idea was to do some kind of a
survey around the object on different types of surfaces so we could get some feel for how
it varies over an object, for example, and we did throw in a hypervelocity gun, we'll
leave that to the designers to figure out how to do that but, yes and deed.
Same on some of the other topics, to really get a feel for how the surface varies around
the object.
Beatty: One of your slides called for determining the gravitational field quickly.
This is normally done - my name is Dave Beatty, Mars Program Office - this is normally
done by putting an object into orbit around a planetary body and tracking its position
very precisely or by carrying a gravimeter across the surface and making surface
measurements.
I don't see that either of those is a particularly quick way of doing it.
Were you thinking of those two or did you have some other way of making that measurement
in mind?
Johnson: We don't have a technique or solution in mind.
It would just be nice if we were able to do that quicker.
Answer: One approach you might consider is this is a small body so maybe you can use
multiple small orbiters to do that quicker or small bodies and have it ejected or
something like that.
Again, we didn't know but the idea of being able to deal with that problem would really
be good.
Johnson: The idea, though, is the human crew could test two or three different
techniques.
Question: I just wanted to ask a question on operational approach to an actual
interception to a Near Earth Object that we're worried about.
Excuse my ignorance on it, I haven't been part of any of these discussions before.
These techniques seem to imply that you know that this is coming a long time ahead of
time.
I know you're testing out these techniques on a human mission but in actual operational
scenario, you have to detect this Near Earth Object and know its immediate risk to the
earth, right?
And so that means to employ some of these techniques, you need to know about that a long
time ahead of time, be able to get the orbital mechanics worked out so that you can get a
space craft there to apply one of these techniques.
Is that the general assumption that you have to detect this a long time ahead of time?
Johnson: Yes.
The most important component of planetary defense is find them early.
find them early, find them early.
Question: So you have techniques for interception, for more immediate detection.
Johnson: We probably have to resort to the nuclear standoff.
Question: Quick question about the gravity field determination in orbiting.
It's very difficult to orbit the small guys and the reason is the gravity is so small
that the solar perturbation is dominant.
In fact the threshold at which it may be not possible to orbit at all is more or less the
region where we are and that if you choose to go to a target at least the size of Itokawa
or something like that, yes you can still orbit but then you need to orbit for at least
several times before you have any chance to infer gravity field.
If you are talking about a 50 m object, it's not clear you can orbit at all, ever.
Question: I hate to belabor the point and we've done some analysis recently and presented
aspects of it at the last two space flight mechanics conferences and you actually don't
need to orbit a small body in order to get the gravity field, you can get the gravity
field by a number relatively slow hyberbolic fly-bys where your V-infinity is on the
order of centimeters per second and that actually is a pretty effective way of measuring
the gravity if you get the right latitudes for your fly-by trajectory and we have some
papers on that if you're interested.
Lindley: Great, yes.
Sure.
Answer: I just wanted to mention that one of the reasons why we're interested in the
gravity field is some of the techniques we've talked about either require a landing,
which means you would need to get there or secondly require flying in, basically
maintaining a station with an object that's rotating and sometimes maintaining that
station very closely.
So, one possibility, of course, would be to develop a system that automatically does that
in a fuel efficient way so, again, the task is what I said, you need to be able to land
something and maybe attach and so forth, so you need to know enough to do that.
Or secondly, if you need to do either orbiting or station keeping, you'll need to know
enough to do that well and potentially stay very close.
Johnson: And, it may not be done by the space craft orbiting the object.
It may just be from the space craft standing off and the object rotating underneath it
that you sample the gravity field.
Question: I think we're making a problem where there is none.
The gravity field that these things is negligible.
You're operating around it like you would with a space station.
If you want to land, you actually need to fire your rocket mounter the other way and
force yourself down onto it and its own gravity for 50 or 100 m object is completely
negligible.
Johnson: I don't think it is so much for landing as it is for maintaining the station
keeping for a gravity tractor.
Question: Yes, but it does that by a lidar sensing its distance from it and again, the
actual gravity field is extremely small.
Schultz: Jochin Schultz from ULR.
I just wanted to maybe take this a little off topic towards both the human mission and
towards precursor missions again.
You were already mentioning that one of the biggest aspects is finding them early.
Another aspect is knowing as much as we can about them.
When we were talking about lunar missions, there was a strong interest in
characterization globally of the lunar surface, in sending notes to different
destinations and get a net of measurements like ILN network for example.
Is there a similar approach or has there been to defining characteristic payload that we
want to send to every NEO that to enable comparative analysis of different objects.
Johnson: We didn't specifically talk about the components of such a package might be and
certainly an idea that has been talked about in planetary defense discussion but building
up a catalog of characteristics for different types of asteroids so that whenever we are
eventually faced with such an object, we already have a lot of knowledge about that type
of object so that we don't necessarily have to do a full characterization mission against
it before we do a mitigation campaign.
Olson: Okay, ladies and gentlemen.
Thank you very much.
That was another excellent panel.
[APPLAUSE] We are now on break.
We will resume at 3:00, 1500 sharp and following the break the two sessions will be Chris
Colbert leading the synergies with Moon and Mars and Gail Allen leading the policy.
So see you back at 3:00 sharp.