Author Topic: Deimos and Phobos Spacecraft  (Read 35707 times)

Offline kato

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Re: Deimos and Phobos Spacecraft
« Reply #20 on: 03/14/2015 11:04 AM »
the small Mars Express seems to do the most of its flybys.
Mars Express ain't "small". It's straight down the middle sizewise for the five current Mars Orbiters for dry weight and carries the second-largest scientific payload, twice as much as MAVEN in third place.

And the flybys have more to do with the relative orbits of what's twirling around Mars.

Offline Blackstar

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Re: Deimos and Phobos Spacecraft
« Reply #21 on: 03/14/2015 01:56 PM »
So much can be done at those fascinating little worlds in partnership with telerobotics and sample return probes.

There's really no good evidence that this is true. I don't know of any studies that have looked carefully at the value of telerobotics.

I didn't come by the idea(s) all by myself - exploration papers by various Universities and studies by Lockheed Martin, Boeing and others over the years have often proposed such things. And much smarter minds than me have extolled mixed manned and robotic exploration missions in recent years. I think when I first heard of the idea(s) was during the Augustine commission a few years back. Also; since such a mixed manned/robotic Mars mission has never been done - yet - then talking about 'good evidence' being lacking is premature, I feel.

I know that it has been mentioned for a long time--many decades in fact. I remember seeing it in Singer's Phobos book back in the 1980s. But other than a workshop or two held at Goddard a few years ago (I have detailed notes on that somewhere, I'll try to find them), it has not been studied. What happens is that people assert that this is true, justify it with a few sentences about latency, and then assume that it is a settled issue: telerobotics from Phobos is a superior thing.

But there's no good detailed examination of this issue involving lab work, experiments, experts in a bunch of fields from robotics to machine cognition to sensors, to science. It all has to be done in comparison to other things, like robotic missions controlled from Earth. And in fact, it may be the case that telerobotics is becoming less and less relevant all the time as machine autonomy gets better and better.

A simple example is that when people first started claiming that telerobotics on Mars was a good thing, several decades ago, they usually talked in terms of navigating a rover over difficult terrain. They expected that it would be like what the Soviets did with their Lunokhods, with somebody looking at a TV screen and driving a rover. But today the driving part is actually a lot easier to do autonomously--a person looks at a video screen, points the cursor at a location, and then tells the rover "You drive to this point" and the rover then figures out all the individual decisions and obstacle avoidance itself. So the person's value is changed here and the human is only needed for the big decisions, not the little ones like avoiding rocks.

This leads to two questions: 1-does it matter if the human making those big decisions is on Earth or in Mars orbit? 2-is there anything else that the human can do better when there is a short lag time?

I don't know the answer to 1 or 2. But for question 1 you can see how the human may only be required to make big decisions sporadically, not every second, and so it may not matter if the human is in Mars orbit.

My point is that there's no detailed study of this issue. There are some individual experiments. But to really answer the question it requires a bunch of experts exploring a lot of options and capabilities and technology development. And because we are not going to Mars at least for a couple of decades, it is important to try and figure out where autonomous vehicle capabilities will be 20 years from now. If by 2040 nobody drives a car anymore and we just order one up on devices implanted in our craniums and let the machine do all the navigating, maybe that technology will be easily applicable to Mars as well and telerobotics from Mars orbit won't matter one bit.

Again, my point is that we don't know, and therefore we cannot simply assert that it is true.

Offline Blackstar

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Re: Deimos and Phobos Spacecraft
« Reply #22 on: 03/14/2015 02:21 PM »
Further to my post above, take two real world examples from today: the Predator and Global Hawk UAVs (drones).

Both perform essentially the same mission, surveillance, but both operate in different ways. When the operator is going to land a Predator he assumes flight control over the aircraft. He looks out the nose of the airplane via video camera. He lines it up with the runway, steers using a stick, controls speed using a throttle, and adjusts flight control surfaces in real time. The pilot is directly in control of the machine.

For the Global Hawk, if the operator is going to land the aircraft he goes to his computer screen, uses a cursor and a pull-down menu, and selects "Land." The plane then lands itself. There's no video camera or direct input to control surfaces.

Those two examples essentially bracket the issues for telerobotics at Mars. Is there anything you want to do on Mars that either requires, or greatly benefits from having a human almost directly in the loop controlling the machine? Or can an operator essentially give the machine commands and let it figure out all the details?

Now I don't think the answer is that humans are essential for controlling a machine on Mars in near real time. It doesn't seem likely that there is anything there that will require that short term decision making. The real question is if there is anything that is better with the human in that short term control--and not just better, but so much better that it really justifies the cost?

Again, I don't think this has been studied in any systematic or comprehensive way.




Offline TakeOff

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Re: Deimos and Phobos Spacecraft
« Reply #23 on: 03/14/2015 03:21 PM »
the small Mars Express seems to do the most of its flybys.
Mars Express ain't "small". It's straight down the middle sizewise for the five current Mars Orbiters for dry weight and carries the second-largest scientific payload, twice as much as MAVEN in third place.

And the flybys have more to do with the relative orbits of what's twirling around Mars.
Yes, true. Mars Express is more ambitious than I thought. Only MRO and the Vikings had more payload mass, as far as I can tell. But Maven and ISRO-MOM are specialized atmospheric probes, and ISRO-MOM is much of a tech demo mission. Mars Express has given far more data about Phobos than any of the other Mars orbiters. I wish they had been designed, by both instrument and orbit, to do more with the Martian moons.

(Maybe they counted on the failed Russian Fobos-Grunt mission to take care of Phobos, and didn't want to overlap too much with it would do anyway?)
« Last Edit: 03/14/2015 03:39 PM by TakeOff »

Offline TakeOff

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Re: Deimos and Phobos Spacecraft
« Reply #24 on: 03/14/2015 03:27 PM »
What about having the next mission to Mars, crash its upper stage into the surface of Phobos or Deimos, to create a dust plume to observe, LCROSS style?


Offline Jim

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Re: Deimos and Phobos Spacecraft
« Reply #25 on: 03/14/2015 04:08 PM »
Planetary protection rules wouldn't allow crashing a stage.  That is why all mars missions are targeted away from mars to prevent the upper stage from hitting it

Offline libs0n

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Re: Deimos and Phobos Spacecraft
« Reply #26 on: 03/14/2015 06:35 PM »
With all the fuss lately about the cost and difficulties of EDL, surface power systems, dust mitigation, possible crew contamination of the Martian surface etc - as I have before, I would like to beat the drum again that rather than go to a free-range asteroid or even the Martian surface for now, that the DRM emphasis should instead be on sending humans to the Martian moons as the next goal.


I think the implied roadmap under the current admin is for a mission to Phobos as the next intermediate step after the ARM mission and in the post ISS timeframe.

http://spacenews.com/41019ahead-of-congressional-hearing-nasa-floats-phobos-pit-stop-on-road-to-mars/
« Last Edit: 03/14/2015 06:47 PM by libs0n »

Offline Blackstar

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Re: Deimos and Phobos Spacecraft
« Reply #27 on: 03/14/2015 06:59 PM »
With all the fuss lately about the cost and difficulties of EDL, surface power systems, dust mitigation, possible crew contamination of the Martian surface etc - as I have before, I would like to beat the drum again that rather than go to a free-range asteroid or even the Martian surface for now, that the DRM emphasis should instead be on sending humans to the Martian moons as the next goal.


I think the implied roadmap under the current admin is for a mission to Phobos as the next intermediate step after the ARM mission and in the post ISS timeframe.

http://spacenews.com/41019ahead-of-congressional-hearing-nasa-floats-phobos-pit-stop-on-road-to-mars/

You'll hear more about this in a few weeks.

Offline redliox

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Re: Deimos and Phobos Spacecraft
« Reply #28 on: 03/14/2015 07:02 PM »
Lovely to see the responses this thread has received.  If anyone has the info, I'd like to see a list of proposals for Deimos & Phobos exploration that are relatively recent - i.e. ~2005 onwards.  I'm aware the Discovery thread cites three but only PADME I know of best (hence you'll all notice a reference link to it at the thread's very beginning).  In addition a handful of others were previously proposed (on that note, thanks for the reference image of ALADDIN Blackstar - it was the first time I saw an actual design image of that proposal).

The bulk of Deimos/Phobos data comes from the Vikings and Mars Express; Mariner 9, MGS, and MRO have done sprinkling of Phobos observations (and the MRO's spectroscopy potentially insightful).  Phobos 2 was obviously cut short, but at the least it was the first probe to notice a chemical difference between what's referred to as the "red" and "blue" terrain.  Collectively, all their data suggest Deimos and Phobos are:
1) Only superficially akin to known asteroids.
2) Spongelike inside, yet curiously dry on the outside for something possibly icy.

Europa and Enceladus definitely are the golden apples of moons, but I suspect Deimos and Phobos may be a small set of golden keys regarding solar system formation.  After all when you think about it, Mars' moons are both ancient and out of place; something curious happened to them.  *kicks the heel of the nearest Mars scientist for neglecting study of the moons*
« Last Edit: 03/14/2015 07:02 PM by redliox »
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Offline redliox

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Re: Deimos and Phobos Spacecraft
« Reply #29 on: 03/14/2015 07:12 PM »
With all the fuss lately about the cost and difficulties of EDL, surface power systems, dust mitigation, possible crew contamination of the Martian surface etc - as I have before, I would like to beat the drum again that rather than go to a free-range asteroid or even the Martian surface for now, that the DRM emphasis should instead be on sending humans to the Martian moons as the next goal.


I think the implied roadmap under the current admin is for a mission to Phobos as the next intermediate step after the ARM mission and in the post ISS timeframe.

http://spacenews.com/41019ahead-of-congressional-hearing-nasa-floats-phobos-pit-stop-on-road-to-mars/

You'll hear more about this in a few weeks.

I hope so.  A vehicle that can land on the moons could easily just be a habitat module with legs attached.  I never favored the ARM plan, but the one charm I liked was the possibility of reusing similar tech at the Martian moons.  Chances are if Congress threatens complete cancellation the efforts should be redirected to Mars, starting with the moons.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Blackstar

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Re: Deimos and Phobos Spacecraft
« Reply #30 on: 03/15/2015 02:41 AM »
I hope so.  A vehicle that can land on the moons could easily just be a habitat module with legs attached.  I never favored the ARM plan, but the one charm I liked was the possibility of reusing similar tech at the Martian moons.  Chances are if Congress threatens complete cancellation the efforts should be redirected to Mars, starting with the moons.

You might have noticed that some of the ARM artwork now shows Phobos as opposed to an asteroid.


Offline redliox

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Re: Deimos and Phobos Spacecraft
« Reply #31 on: 03/15/2015 11:00 AM »
I hope so.  A vehicle that can land on the moons could easily just be a habitat module with legs attached.  I never favored the ARM plan, but the one charm I liked was the possibility of reusing similar tech at the Martian moons.  Chances are if Congress threatens complete cancellation the efforts should be redirected to Mars, starting with the moons.

You might have noticed that some of the ARM artwork now shows Phobos as opposed to an asteroid.

If they want to salvage or (as a longshot) validate the asteroid redirect plan, Phobos (and hopefully Deimos too) is the best option; directs things back to Mars and fewer arguments against.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline baldusi

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Re: Deimos and Phobos Spacecraft
« Reply #32 on: 03/15/2015 01:35 PM »
Well, one thing I wonder is about mission travel time, short of Venus, Mars as close as you can get in our solar system. And Deimos is pretty shallow in the Mars gravity well. And once done, they would have proven about 80% of the technologies for a Phobos human mission. It would be brilliant.

Offline jacob.a.englander

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Offline Blackstar

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Re: Deimos and Phobos Spacecraft
« Reply #34 on: 03/15/2015 04:39 PM »
I'm an AIAA member, but don't have access to that paper. But here's another recent example.

Offline redliox

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Re: Deimos and Phobos Spacecraft
« Reply #35 on: 03/15/2015 06:39 PM »
Well, one thing I wonder is about mission travel time, short of Venus, Mars as close as you can get in our solar system. And Deimos is pretty shallow in the Mars gravity well. And once done, they would have proven about 80% of the technologies for a Phobos human mission. It would be brilliant.

Frankly the only difference between going to Phobos versus Deimos is a modestly larger fuel load to change from a ~30 orbit to a ~8 hour orbit around Mars.

Definitely yes regarding Deimos as a shallow target.  Doing the math, even an Orion could break into a matching orbit with Deimos if sent on a one-way trip.  I favor Deimos for this fact and that it is in near-synchronous orbit. 

As far as technology, for a Mars mission it would enable demonstrating probably closer to 66% of what's needed.  The remainder does deal with aerobraking/aerocapturing and then landing a crewed vehicle.  Ultimately it depends on what NASA decides as an architecture, which seems perpetually in flux.  Any orbiting elements would get a thorough workout via the moons for certain and bring home samples for science.
"Let the trails lead where they may, I will follow."
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Offline TakeOff

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Re: Deimos and Phobos Spacecraft
« Reply #36 on: 03/17/2015 10:47 AM »
Wouldn't a drill core or multiple sample sites (like Hayabusa 2) be scientifically much more useful than picking up one single big boulder as in ARM-B?

I think that NASA cannot realize ARM directly. They have to make it step by step in order for its ambition to have a realistic chance. A drill to Phobos with sample return would be a good first step for ARM, and as a second preparatory step they could pick up a rock from Deimos, and as a third preparation before the end of the 2030's...
« Last Edit: 03/17/2015 10:47 AM by TakeOff »

Offline baldusi

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Re: Deimos and Phobos Spacecraft
« Reply #37 on: 03/17/2015 11:30 AM »
Well, one thing I wonder is about mission travel time, short of Venus, Mars as close as you can get in our solar system. And Deimos is pretty shallow in the Mars gravity well. And once done, they would have proven about 80% of the technologies for a Phobos human mission. It would be brilliant.

Frankly the only difference between going to Phobos versus Deimos is a modestly larger fuel load to change from a ~30 orbit to a ~8 hour orbit around Mars.

Definitely yes regarding Deimos as a shallow target.  Doing the math, even an Orion could break into a matching orbit with Deimos if sent on a one-way trip.  I favor Deimos for this fact and that it is in near-synchronous orbit. 

As far as technology, for a Mars mission it would enable demonstrating probably closer to 66% of what's needed.  The remainder does deal with aerobraking/aerocapturing and then landing a crewed vehicle.  Ultimately it depends on what NASA decides as an architecture, which seems perpetually in flux.  Any orbiting elements would get a thorough workout via the moons for certain and bring home samples for science.
Well, there's the low orbit, plus the plane change, plus the escape delta-v. Deimos is easier on everything. But you qualify everything for a Phobos mission. On thing that might be different, though, is that since Deimos is so much smaller, it might have a mushier surface. That might become a problem if you want to bring a piece of it and it has the consistency of an ice cream.
But otherwise, as a robotic precursor, you could bring a bigger piece out of Deimos than from Phobos with the same sized robot. Thus, given the SLS is sort of defined, I would guess that it would be a better target for the ARM. Besides, if humans are going to Phobos next, you can get samples from both.

Offline Alpha_Centauri

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Re: Deimos and Phobos Spacecraft
« Reply #38 on: 03/17/2015 09:20 PM »
A Phobos sample return mission is being proposed as a follow-on to Exomars for launch mid next decade, with ESA again partnering with Russia.  Below is a link to a CDF study on the joint mission, essentially merging ESA's Phootprint with Russia's Phobos-Grunt 2.

http://sci.esa.int/future-missions-office/55323-cdf-study-report-phobos-sample-return/#

Offline redliox

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Re: Deimos and Phobos Spacecraft
« Reply #39 on: 03/19/2015 10:51 AM »
A Phobos sample return mission is being proposed as a follow-on to Exomars for launch mid next decade, with ESA again partnering with Russia.  Below is a link to a CDF study on the joint mission, essentially merging ESA's Phootprint with Russia's Phobos-Grunt 2.

http://sci.esa.int/future-missions-office/55323-cdf-study-report-phobos-sample-return/#

Good find!  It looks promising; although the mission focuses on sampling Phobos they include rendezvousing with Deimos beforehand, so it would gather details about both satellites in addition to the sample.  They seem to heavily baseline optical and infrared instruments first followed by a neutron spectrometer, a dust sensor; additional surface instruments (ala alpha-proton-x-ray spectrometer) are implied but not specified for now. 

Design and objective aside, cooperation with ESA will allow this probe to receive better monitoring.  The Phobos-Grunt failed because the Russians couldn't fully track it on entering orbit, otherwise they could have detected the problem sooner and possibly saved the mission. 
"Let the trails lead where they may, I will follow."
-Tigatron

Tags: Deimos Phobos Mars