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Totally Random Thought About Spacesuits

There's a capability that spacesuits should have that should be cheap and fairly easy to implement but that I haven't heard mentioned.

A spacesuit should be aware of its location and the relative locations of other spacesuits, vehicles, and anything else with which it maintains radio contact. The audio system within the helmet should take this into account. If you're in a suit on an EVA and another astronaut who is above, behind, and to the left of you speaks, it should sound like they're above, behind, and to the left.

This would be particularly useful for moon and Mars colonies, where lengthy EVAs could put significant distance between astronauts and terrain could impede line of sight. It doesn't even have to be precise, but if a natural language statement like "Hey, look at this!" doesn't need to be followed by a location statement or require that the other astronaut look around to see where their companion is to respond then I think that'll be both more efficient and make interaction while suited more natural and less distracting.

One might even want the system to adjust a speaker's volume (to a point) according to their distance.

Just a thought.

Comments

( 16 comments — Leave a comment )
(Deleted comment)
zandperl
Nov. 14th, 2009 12:14 am (UTC)
What makes you think this would be "cheap and fairly easy to implement"? In order to sense the direction of another thing you would either need multiple omnidirectional receivers (3 receivers if constrained to a plane, 4 if not) and a signal processing system to beat the received signals against each other and use that to calculate direction of the signal's source, or else you would need multiple unidirectional receivers (how many depends on how narrow beamed the unidirectional is) and tie each unidirectional receiver to a separate speaker inside the helmet. Omnidirectional radio/microwave receivers look like cellphone and laptop antennas while unidirectional radio/microwave receivers look like satellite dishes, so hardware-wise multiple omni receivers would be better. But signal processing for beating two signals received less than a foot away from each other would be technically difficult primarily because the distance between the two receivers is on order of the wavelength size, but also because it's a difficult challenge in the first place - the Very Large Array achieves this by running miles of extra wires to the telescopes nearest to the computer room so that each telescope has the exact same length of wire between the telescope and the computer room, and then there's programming the Fourier transforms to turn the beats into directional information (while something the size of a graphing calculator can perform such calculations for a single instant of data, I think you need at least a laptop computer and possibly a supercomputer to do it in realtime).
dorklord07
Nov. 14th, 2009 04:16 am (UTC)
I was going to type out something similar to this, but this fellow did a much better job than I ever could have.

Also, getting NASA to do new things? Not happening.
datan0de
Nov. 14th, 2009 06:10 am (UTC)
I just replied to zandperl's comment. If you don't mind, I'd like to get your thoughts on that reply as well as hers. I'm not an expert on this topic by any means, but I think that there's a much easier way by focusing on relative signal strength across scattered receivers rather than lag time.
zandperl
Nov. 14th, 2009 03:38 pm (UTC)
Thanks. ;) datan0de does suggest a possible way of doing this on a fixed surface below.

As for NASA not doing new things, you should check out the many Tweeting astronauts, such as @Astro_Mike (Mike Massamino, first tweeter in space and on the last mission to service the HST), @Astro_Jose (Jose Hernandez, tweets in both English and Spanish), and @Astro_TJ (TJ Creamer, who will be tweeting from the ISS starting Christmas). True those are no-budget items, but I've been favorably impressed with their innovation in EPO (Education and Public Outreach) lately.
datan0de
Nov. 14th, 2009 06:06 am (UTC)
There's a simpler way.

No EVA is going to be done at a large distance from a base, whether it's a colony structure or perhaps a vehicle. Assuming there's no functioning equivalent of a GPS system (which, in the case of a permanently manned colony on the moon or Mars seems like an oversight), use 3 or for omnidirectional receivers (minimum) spread around the area of operation at known locations. The receivers pick up a regular ping coming from each suit (not on the audio channel, obviously), and based on relative signal strength at each receiver triangulate a rough location for each suit. Cell towers can be used to locate your cell phone using this technique today. Sure, on the surface local geography can cause uncertainty, but it should be good enough for these purposes. If greater precision is needed then either add more receivers or generate a map of the local interference (such that, for example, the system knows that standing behind that boulder over there causes signal drop out for transmitter A). A PDA could handle this kind of calculation, and it only needs to be done at one location - not in each suit.

The "base" monitors the locations of the suits in the area, and transmits this data in a return pulse to the suits. Each suit thereby gets realtime location information for itself and everything else transmitting in the area. The audio system should have no difficulty adjusting volume and perceived direction for each incoming audio stream.

Yes, I'm assuming that next generation space suits will have a certain degree of smarts that Apollo-era suits did not, but I suspect that's a safe assumption. Nothing I'm proposing here should be heavy, power hungry, or require even the processing capability of an iPhone. Heck, if you want to get snazzy this information could be incorporated into a map of the local area and be available as a heads up display for the astronaut and it could still be done with an iPhone or less.
dorklord07
Nov. 14th, 2009 06:57 am (UTC)
While I can't find much hard data to back me up on this (my books from my Space Systems courses only deal with sensing from ground to space or from space to ground), I get the impression that there would be too much noise to get an accurate measurement.

The lag-based method currently used is highly resistant to the effects of EM radiation from the Sun/Earth/Space Vehicle/Space Debris/etc., since it only requires the receiver to hit on two peaks (or more). Therefore, if the receiver picks up noise, it won't matter, because the signal will still peak (ie, go from 0 to some percentage of 1).

With measuring signal strength, you have to account for noise coming from the literally hundreds of other radiating items floating around the receiver. On Earth, this means turning on the toaster fries your WiFi. In space, however, there's a toaster the size of the sun.

This should all be taken with a grain of salt, though, since I'm extrapolating most of it, and I'm a sociology major now. XD

I'm extrapolating this from a chapter in "Understanding Space: An Introduction to Astronautics" by Jerry Jon Sellers, last updated in 2005, as well as these sites:

http://www.velocityreviews.com/forums/t372027-how-to-measure-signal-strength.html
http://www.ezlan.net/wbars.html
datan0de
Nov. 14th, 2009 07:10 am (UTC)
LOL! I see I'm not the only one up late geeking out! While you were typing your reply to my comment I was also typing a reply to my comment, also addressing the problem of noise and signal interference. Spooky!

Let me know what you think!
radven
Nov. 14th, 2009 09:11 am (UTC)
I've seen demonstrations of UWB (ultra wide band) communication tech that not only provides high-bandwidth data over medium distance, but also precise relative locations, and also short range "radar" from the signal reflections.

The processing for all of this was able to be handled in real-time in a 1999 vintage laptop.

This sounds like a perfect scenario to use UWB in.

- Chris

PS: I am good friends with a genuine NASA senior engineer who is also on LJ. I will mail a link to him. :-)
zandperl
Nov. 14th, 2009 03:52 pm (UTC)
On Earth, this means turning on the toaster fries your WiFi. In space, however, there's a toaster the size of the sun.

Communications take place on radio and microwave bandwidths. Radiation at (most of) these wavelengths comes right through the Earth's atmosphere (otherwise we'd have to put radio telescopes in space like we do with far IR telescopes [IRAS, Spitzer] or x-ray telescopes [Chandra]), so there's as much solar interference on the Earth as on the Moon or in orbit around the Earth. You just need a signal stronger than the Sun, and we already do this on Earth.
datan0de
Nov. 14th, 2009 06:58 am (UTC)
Stupid Insomnia!
Here's another possibility. How would this work as an alternative? Each suit's "ping" is actually two (or better still- three!) pulses on different wavelengths. Distance could be determined by the phase shift between the waves. You'd still use multiple receivers, but this could provide a more precise location with less interference from geography.

Plausible, or am I talking out of my butt? I'm less than completely awake right now, so I may be way off kilter, but if I don't put this thought down then it'll keep me up all night.
dorklord07
Nov. 14th, 2009 08:11 am (UTC)
Re: Stupid Insomnia!
Hahaha. I think "HOLY GAWD WAVES!" I would think this would make the situation worse rather than better, as you would need to coordinate the suits so that the waves didn't interfere with each other.

While thinking about it, though, you could conceivably use a web of laser-targeting-system-type devices. Although that seems even more expensive than putting the damn thing in space in the first place. XD
zandperl
Nov. 14th, 2009 03:47 pm (UTC)
Good point that the triangulation/analysis does not need to be done on board the spacesuits. However, I question other things you say.

No EVA is going to be done at a large distance from a base,

So you're not suggesting this for astronauts working on the ISS or a Space Shuttle (equivalent)?

based on relative signal strength at each receiver triangulate a rough location for each suit. Cell towers can be used to locate your cell phone using this technique today.

Are you sure they do it based upon signal strength? You're probably right, but I'm not sure. Also, what size scale can the signal strength method resolve? If there are two astronauts working on the HST in the Space Shuttle's bay for example, could sensors on the Space Shuttle resolve the two astronauts? Or two astronauts working on the exterior of the ISS, such as installing another module.

If the astronauts are working farther apart than that, then I see no reason to even perform a realtime analsis of their locations, just use where they're supposed to be working, or GPS signals.

A PDA could handle this kind of calculation, and it only needs to be done at one location - not in each suit.

Yeah, signal strength (if accurate enough) can be performed on a graphing calculator. Even less overhead if the ping takes place every 5 seconds or something and it only updates that often.
datan0de
Nov. 14th, 2009 04:49 pm (UTC)
So you're not suggesting this for astronauts working on the ISS or a Space Shuttle (equivalent)?

I probably should have quantified "large distance". I could be wrong, but I wouldn't imagine an EVA (either in orbit or on the surface) taking an astronaut more than a couple of miles out without a vehicle, in which case the vehicle would function as the base.

Are you sure they do it based upon signal strength?

I wouldn't bet my mortgage on it, and I don't have any links to back it up, but I'm fairly confident. As an interesting side note, Slashdot had an article a while back about how rain could be detected/mapped in localized areas within a city using just variations in power consumption for the cell towers in the area. The towers automatically boost signal strength to overcome interference.

Also, what size scale can the signal strength method resolve? If there are two astronauts working on the HST in the Space Shuttle's bay for example, could sensors on the Space Shuttle resolve the two astronauts?

Excellent (and important) question! I'm assuming that a subcarrier identifies which signal is coming from which suit (along with sending telemetry data), but I doubt that the signal strength method would allow the system to resolve the relative positions of two astronauts who were within arm's reach of each other, which would kind of defeat the point.

Could phase shift provide that level of resolution? Uh... I dunno. Perhaps radven's friend can shed some light.
zandperl
Nov. 14th, 2009 06:21 pm (UTC)
Slashdot had an article a while back about how rain could be detected/mapped in localized areas within a city using just variations in power consumption for the cell towers in the area.

Fascinating! I will have to find that link. Most radio wavelengths can go right through the atmosphere, but most microwave (which is what cellphones use) have trouble with water (so clouds and active precipitation). Never occurred to me that they'd have to choose a bandwidth that was less affected by water, and they'd still have to compensate for it.

Could phase shift provide that level of resolution?

I believe this falls into the "resolving objects to 1/4 of the wavelength" rule, so whether it could resolve two different people just depends on the wavelength of the signal used.

brian1789
Nov. 14th, 2009 10:17 pm (UTC)
Well... actually, someone at NASA came up with a similar directional-sound-channel idea about 12 years ago, and it has been in use -- not in suits as yet, but in launch control headsets. The lead folks at the pad during countdowns have to monitor lots of audio channels, and that helps them track who is saying what...
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