<html>
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 11 (filtered)">
<title>RE: [Sis-csi] Limit of Cislunar domain</title>
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:blue;
text-decoration:underline;}
p
{margin-right:0in;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman";}
span.emailstyle18
{font-family:Arial;
color:navy;}
span.EmailStyle19
{font-family:Arial;
color:navy;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=EN-US link=blue vlink=blue>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Aha! That makes sense. So
earth-moon L2 is clearly part of lunar mission infrastructure. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m a little concerned that if we
include sun-earth L2, it begs the question about why we’re doing that for
cislunar missions (or maybe it is better to say for lunar programs). Unless
there is some indicator that there is some use for lunar missions with relays
out that far. But it’s hard to see why sun-earth L-points would be part
of a lunar infrastructure. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>We can always say, as Keith said, that “10
seconds is a nice boundary”. Lunar infrastructure that we know
about is at ~3.5 seconds, so for “margin” for unanticipated
elements, we picked the next round number up, namely 10 sec. I favor
that, because if we list the sun-earth L2 points as a consideration for
cislunar, someone will challenge us to say what lunar mission stuff is out
there. Or maybe not. Actually, it’s probably not a big deal
either way. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Keith (Scott), I think you need to decide
first, whether we use the table (per my input in Sec 2), and second, if we do,
whether we mention sun-earth L2 as justification for the 10-second round-up.
</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> -=- Mike</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Mike Kearney</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>NASA MSFC EO-01</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>256-544-2029</span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Jason A. Soloff
[mailto:jason.a.soloff@nasa.gov] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, October 09, 2005
10:57 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Kearney, Mike;
sis-csi@mailman.ccsds.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Sis-csi] Limit of
Cislunar domain</span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Mike -</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>The thinking at Earth-Moon L2 is to use a
halo orbit that keeps Earth in view at the same time it provides coverage to
the lunar far-side. There are a number of these orbits studied within
Exploration as well as in the SCAWG. No decision has been made whether or
not to use the L2 halo orbit, but its a nice option to have in your pocket...</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>- Jason</span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
</div>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>____________________________________________</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>"It's kind of fun to do the impossible." - Walt
Disney</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Jason A. Soloff</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Chief Engineer</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Exploration Communication & Navigation Systems</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Constellation Systems</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>NASA / Goddard Space Flight Center</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Code 567 / B19 / S046</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Greenbelt, MD 20771</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Phone: (301)286-1368</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Blackberry: (301)356-3708</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Fax: (301)286-1750</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>E-Mail: <a href="mailto:Jason.A.Soloff@nasa.gov">Jason.A.Soloff@nasa.gov</a></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
</div>
<blockquote style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Keith Hogie
[mailto:Keith.Hogie@gsfc.nasa.gov] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, October 09, 2005
7:35 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Krupiarz, Christopher<br>
<b><span style='font-weight:bold'>Cc:</span></b> Kearney, Mike;
sis-csi@mailman.ccsds.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Sis-csi] Limit of
Cislunar domain</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> I used the Sun/Earth L1/L2 values to give a worst case boundary
based on propagation delay. Technically they are beyond the Moon's
orbit but they are locations that are already being used (e.g. SOHO,
WMAP). I included them because their delay is not real bad and you could
probably still hold a voice converstation, run TCP, or do something interactive
over that sort of link. Once you get beyond them, the next stop is pretty
much Mars and those delays put you in a whole different category. 10
seconds seemed to be a nice boundary that also fit with locations being
used. <br>
<br>
I didn't worry about the Lunar Lagrange points since they are not that
far from the Moon. It looks like they are 61,500 Km away from the
Moon. I was listing delays from an Earth centric view which probably fits
with Cislunar. I guess the question is whether we want to stick to purely
Cislunar at 2.5 seconds or if we want to stretch to Sun/Earth L1/L2 which would
cover anything out to 10 seconds. <br>
<br>
Keith Hogie<br>
<br>
</span></font></p>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabIndex=-1>
</span></font></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
sis-csi-bounces@mailman.ccsds.org [mailto:sis-csi-bounces@mailman.ccsds.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Kearney, Mike<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, October 09, 2005
9:18 AM<br>
<b><span style='font-weight:bold'>To:</span></b> sis-csi@mailman.ccsds.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Sis-csi] Limit of
Cislunar domain</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I was thinking the implication was that if
L2 is on the far side, it’s not in line-of-sight of earth. I think
that’s the reason radio telescope projects have been talked about for L2,
because the moon shields them from earth’s RF noise. And if the
comm relay at L2 is not in RF line-of-sight, then another relay would be needed
anyway. But I’m not a celestial mechanics guy, I’m just going
from diagrams I’ve seen. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>In any case, I think it’s safe to
say that lunar missions could have some TBD elements at L2, hence extending our
definition of Cislunar to that point. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>But another source says that L2 is 92,000
Km past the moon.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a
href="http://www.projectpluto.com/interest.htm">http://www.projectpluto.com/interest.htm</a></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The earth-moon distance is 385,000 Km, and
the round trip time delay for earth-moon is 2.5 sec, I would think that the L2
round trip time would be only 3.5 sec or so. Not the 10 sec in your
table. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>385+92= 477,000 Km for earth-moon L2, not
the 1,500,000 Km that you listed. I wonder if you got the distance for
earth-sun L2 instead of earth-moon L2? </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m still confused about who wrote
this table up to begin with. Was it Chris or Keith (Hogie)?
It’s a great way to define the cislunar domain, IMHO, anyway. </span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> -=- Mike</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Mike Kearney</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>NASA MSFC EO-01</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>256-544-2029</span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabIndex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Krupiarz,
Christopher [mailto:Christopher.Krupiarz@jhuapl.edu] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Saturday, October 08, 2005
10:15 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Kearney, Mike;
sis-csi@mailman.ccsds.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Sis-csi] Limit of Cislunar
domain</span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p style='margin-bottom:12.0pt'><font size=2 face="Times New Roman"><span
style='font-size:10.0pt'>Mike,<br>
<br>
L2 being on the far side of the Moon is what makes it nice as a comm relay for
assets that are also on the far side. I'm not sure about L4 and L5, but
I'm with you about not being confident in my knowledge of how these points could
be used. Off-hand if you're using relays to save power/mass on a lander,
it would seem using L4 & L5 wouldn't help much. However, L4 & L5
would give some coverage of the far side. <br>
<br>
Chris<br>
<br>
<br>
-----Original Message-----<br>
From: sis-csi-bounces@mailman.ccsds.org on behalf of Kearney, Mike<br>
Sent: Sat 10/8/2005 10:10 PM<br>
To: sis-csi@mailman.ccsds.org<br>
Subject: RE: [Sis-csi] Limit of Cislunar domain<br>
<br>
Keith (Hogie): I was plugging your table below into section 2...<br>
<br>
<br>
<br>
0000.1 sec - Interaction between rovers, landers, (e.g. local<br>
environment)<br>
0000.1 sec - Low-Earth orbit ( a few hundred kilometers one-way)<br>
0000.1 sec - Low-Lunar orbit ( a few hundred kilometers one-way)<br>
0000.1 sec - Low-Mars orbit ( a few hundred kilometers one-way)<br>
0000.5 sec - Earth geosync orbit (36,000 kilometers one-way)<br>
0002.5 sec - Earth-to-Moon (384,000 kilometers one-way)<br>
0010.0 sec - Earth to L1 or L2 (1,500,000 kilometers one-way)<br>
------------------Limit of Cislunar domain<br>
0366.0 sec - Earth to Mars (closest = 55.000.000 kilometers one-way, 6<br>
minute, RTT)<br>
2673.0 sec - Earth to Mars (farthest = 401,000,000 kilometers one-way,<br>
45 minute RTT)<br>
<br>
<br>
<br>
But I started wondering about the usage of L1 and L2. L1 is closer to<br>
earth than the moon, so it would really not be a factor in establishing<br>
the boundary of cislunar missions in terms of time delay. L2 is on the<br>
far side of the moon and wouldn't have much value for comm relays. Did<br>
you have some other mission in mind? <br>
<br>
<br>
<br>
In terms of comm relays, I was wondering if L4 or L5 (preceding or<br>
following the moon in earth orbit) have more value as comm relays. And<br>
I started wondering if anyone what Exploration was considering as<br>
possible uses for those Lagrangian points. I'm not confident in my<br>
understanding, and I just want whatever text that goes into the Cislunar<br>
GB to be credible. <br>
<br>
<br>
<br>
Anyone have any insight into that? <br>
<br>
<br>
<br>
I ask the question, because a better description of what might be done<br>
at the Lagrangian points would help the "mission characteristics"<br>
section. <br>
<br>
<br>
<br>
-=- Mike<br>
<br>
<br>
<br>
Mike Kearney<br>
<br>
NASA MSFC EO-01<br>
<br>
256-544-2029<br>
<br>
________________________________<br>
<br>
From: sis-csi-bounces@mailman.ccsds.org<br>
[<a href="mailto:sis-csi-bounces@mailman.ccsds.org">mailto:sis-csi-bounces@mailman.ccsds.org</a>]
On Behalf Of Keith Hogie<br>
Sent: Thursday, September 08, 2005 12:55 AM<br>
Cc: sis-csi@mailman.ccsds.org<br>
Subject: Re: [Sis-csi] IP Header Compression<br>
<br>
<br>
<br>
Adrian J. Hooke wrote:<br>
<br>
At 01:40 PM 9/6/2005, Keith Hogie wrote:<br>
<br>
<br>
<br>
I agree we need to consider issues with small packets and low rates,<br>
but how low do we need to go. In all of the missions I have seen (non<br>
deep space), the lowest data rates are 125 bps. This is over an order<br>
of magnitude difference from your 10 bps. <br>
<br>
For the Cislunar environment, we need to figure out what some of our<br>
limits are. Do we really want to burden the Cislunar design with issues<br>
that only relate to Deep Space?<br>
<br>
<br>
Aren't the Lunar missions supposed to be "training" for going to
Mars?<br>
For critical emergency commanding operations, shouldn't we be developing<br>
a robust, unified, reliable, tested system that works wherever you go?<br>
<br>
<br>
For emergency commanding I don't see any difference between Cislunar<br>
or Deep Space. In both cases the solution is to send a string of bits<br>
that gets decoded by hardware and do not need any protocol. The<br>
critical hardware commands are their own frame sync, authentication, and<br>
command all packed into a highly unique string of bits. Most hardware<br>
decoders pick off the bits they are looking at directly from the<br>
receiver and don't involve any flight software. This means that there<br>
is no complex packet processing and the hardware is just looking for<br>
particular sequence of bits. The length of this sequence is not a<br>
function of any CCSDS or IP headers. Getting the command to the<br>
spacecraft just requires radiating the proper string of bits. The<br>
length of the hardware command is just a function of how many bits you<br>
think you need to make sure your command doesn't occur in normal data<br>
transfers. <br>
<br>
My main concern is for all the other operational modes there is a very<br>
large disconnect between things that will work in a Cislunar environment<br>
and a long haul link to Mars. If you consider the following round trip<br>
times (RTT):<br>
<br>
0000.1 sec - Interaction between rovers, landers, (e.g. local<br>
environment)<br>
0000.1 sec - Low-Earth orbit ( a few hundred kilometers one-way)<br>
0000.1 sec - Low-Lunar orbit ( a few hundred kilometers one-way)<br>
0000.1 sec - Low-Mars orbit ( a few hundred kilometers one-way)<br>
0000.5 sec - Earth geosync orbit (36,000 kilometers one-way)<br>
0002.5 sec - Earth-to-Moon (384,000 kilometers one-way)<br>
0010.0 sec - Earth to L1 or L2 (1,500,000 kilometers one-way)<br>
------------------Limit of Cislunar domain<br>
0366.0 sec - Earth to Mars (closest = 55.000.000 kilometers one-way, 6<br>
minute, RTT)<br>
2673.0 sec - Earth to Mars (farthest = 401,000,000 kilometers one-way,<br>
45 minute RTT)<br>
<br>
When you look at distances like these there is a huge break between<br>
Cislunar ones and Mars. In the Cislunar area it is actually
possible<br>
to do interactive things like interactive audio, video, and data access.<br>
You can consider security protocols that negotiate security details. At<br>
L1 and L2 things get a bit uncomfortable at 10 seconds RTT but that is<br>
still manageable. At Lunar distances you can do most anything you do on<br>
Earth. A 2.5 second delay is a bit long for some interactive operations<br>
but it is not really any longer than what happens when you surf the open<br>
Internet and hit a bit of congestion. The main point is that out to L1<br>
and L2 you can actually do interactive operations This also applies to<br>
systems on Mars and orbiting around Mars. <br>
<br>
However, when you move to the long haul link between Earth and Mars,<br>
the RTT jumps up to over 100 or 1,000 times that of the Earth and Moon.<br>
With a 6 to 45 minute RTT, you can't carry on an interactive voice or<br>
video conversation and lots of interactive data access just doesn't<br>
work. On a Earth-to-Mars link you are forced to shift to an operations<br>
concept of two one-way links. Operations must shift into email-like<br>
file store-and-forward or one-way streaming of data. <br>
<br>
So I don't see any real problem with using the same hardware<br>
commanding solution in Cislunar or Earth-to-Mars scenarios. Some file<br>
store-and-forward and one-way streaming operations will also work for<br>
both environments. Of course any acknowledgments on the file-store-and<br>
forward will take lots longer. <br>
<br>
My concern is that other there are lots of protocols and applications<br>
that will work fine in an interactive Cislunar environment but just<br>
don't work for Earth-to-Mars. We don't want to limit our Cislunar<br>
solutions to only those that will also work for Earth-to-Mars. I think<br>
we need to develop our Cislunar solutions and then see if any of them<br>
will also work in a Earth-to-Mars scenario. <br>
<br>
<br>
<br>
----------------------------------------------------------------------<br>
Keith
Hogie
e-mail: Keith.Hogie@gsfc.nasa.gov<br>
Computer Sciences Corp. office:
301-794-2999 fax: 301-794-9480<br>
7700 Hubble Dr.<br>
Lanham-Seabrook, MD 20706
USA 301-286-3203 @ NASA/Goddard<br>
----------------------------------------------------------------------</span></font></p>
</blockquote>
</div>
</body>
</html>