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Redstone
MRO has shifted from the cruise phase to Approach phase. Apparently, the trajectory is so good that TCM-3 was cancelled. This is good news for the prospects for a long life for MRO supporting future missions. TCM-4 is on Feb 28, and MOI on March 10. Only 5 weeks away! smile.gif
RNeuhaus
Good news. I seems that MRO has started to gain its speed due to Mars gravity tug, has not?

What is MOI? Mars Orbit Insertion.

http://mars.jpl.nasa.gov/mro/gallery/cruis...oach_200602.jpg

"It was a very busy time for the team. Many tests were conducted to ensure that the instruments onboard were functioning properly and our navigators performed trajectory correction maneuvers to keep us on a very precise path to Mars."

Speaking of that precision, the third of four possible course corrections was deemed unnecessary this week.

"The navigation solutions have shown a great consistency since the second trajectory correction maneuver was executed on November 18," said Han You, navigation team chief. "More importantly, the current data indicate that the spacecraft aim for insertion into Mars' orbit is well within the projected target. If the current trend continues, the spacecraft will require only a very small nudge to fine tune the final aim."


Rodolfo
ugordan
QUOTE (RNeuhaus @ Feb 4 2006, 05:41 AM)
I seems that MRO has started to gain its speed due to Mars gravity tug, has not?

Where did you hear that? As far as I can see, MRO is sill on the elliptical transfer orbit and too far away to feel Mars' gravity influence. In fact, its heliocentric speed should be decreasing.
MRO won't begin to feel significant pull from Mars probably all the way until around a day or so before MOI.
abalone
QUOTE (Redstone @ Feb 4 2006, 10:06 AM)
MRO has shifted from the cruise phase to Approach phase. Apparently, the trajectory is so good that TCM-3 was cancelled. This is good news for the prospects for a long life for MRO supporting future missions. TCM-4 is on Feb 28, and MOI on March 10. Only 5 weeks away! smile.gif
*

I hope they did a double ckeck in metrics and not just rely on the usual NASA units of ancient Kings appendages and Roman marching steps and bushels of wheat, but mistakes like that couldn't happen could they??
djellison
It's odd to think that from 'aboe' - MRO's burn which actually increase it's speed - but because it will being 'run over' by mars, it will be slowing down w.r.t. Mars itself smile.gif

I hope they release the op-nav imagery - I'm sure it wont be particularly great, but it will make an interesting little movie watchign Phobos and Deimos doing their thing smile.gif

Doug
SFJCody
How many pixels would HiRise get across the disc of Mars now?
mcaplinger
QUOTE (SFJCody @ Feb 4 2006, 07:50 AM)
How many pixels would HiRise get across the disc of Mars now?
*


HiRISE has an IFOV of 1 microradian, so the pixel scale is the distance times 1e-6.
MRO is probably about 7 million km out right now (the simulations on the MRO site don't show the range) so that's 7 km/pixel. Mars is about 7000 km in diameter, so that's about 1000 pixels.

Of course, there are no plans to take such images that I'm aware of. The opnav camera is pointed in a direction almost 180 degrees away from the rest of the science instruments.
djellison
This is from a little PDF I found at the same place as the UHF tracking info
crabbsaline
QUOTE (djellison @ Feb 4 2006, 12:41 PM)
This is from a little PDF I found at the same place as the UHF tracking info
*


Thanks Doug. I had to look up ONC to understand that part of the chart. I wonder what kind of "improved navigation capability" that they anticipate it will yield versus older methods?

I hope to see the ONC images soon. smile.gif
djellison
I think they're using the ONC more as a tech-demonstrator to feed forward to future missions that will require that sort of accuracy. As it is for MRO, 'classical' navigation techniques are probably enough.

They wont be pretty pictures, but they'll be interesting none the less.

Doug
jmknapp
QUOTE (ugordan @ Feb 4 2006, 07:13 AM) *
As far as I can see, MRO is sill on the elliptical transfer orbit and too far away to feel Mars' gravity influence. In fact, its heliocentric speed should be decreasing.
MRO won't begin to feel significant pull from Mars probably all the way until around a day or so before MOI.


True--MRO's speed relative to Mars won't start to increase until Feb. 25, & even then only very slightly until the day of MOI (per the SPICE kernel data).

Here's a chart of the speed for the month of March:

jmknapp
PS: Does anyone know what the field-of-view and resolution of the ONC are?
djellison
http://bookstore.spie.org/index.cfm?fuseac...d=619857&coden=
QUOTE
Abstract
The Optical Navigation Camera (ONC) is part of NASA's Mars Reconnaissance Orbiter (MRO) scheduled for an August 2005 launch. The design is a 500 mm focal length, F/8.3 Ritchey-Chretien with a refractive field corrector. Prior to flight, the off-axis performance of the ONC was measured at visible wavelengths in the off-axis scatter facility at the Space Dynamics Laboratory (SDL). This unique facility is designed to minimize scatter from the test setup to prevent data corruption. Testing was conducted in a clean room environment, and the results indicate that no detectable contamination of the optics occurred during testing. Measurements were taken in two time frames to correct an unanticipated stray light path, which occurred just outside of the sensor's field-of-view. The source of the offending path was identified as scatter from the edges of the field corrector lenses. Specifically, scatter from the interface between the flat ground glass and polished surfaces resulted in significant "humps" in the off-axis response centered at ± 1.5°. Retesting showed the removal of the humps, and an overall satisfactory performance of the ONC. The troubleshooting, correction, and lessons learned regarding the above stray light path was reported on in an earlier paper. This paper discusses the measurement process, results, and a comparison to a software prediction and other planetary sensors. The measurement validated the final stray light design and complemented the software analysis.


Very little info out there though. That's about all I could find.
jmknapp
QUOTE (djellison @ Feb 15 2006, 09:35 AM) *
http://bookstore.spie.org/index.cfm?fuseac...d=619857&coden=
Very little info out there though. That's about all I could find.


Thanks! That paper states that the FOV is 2.8 degrees (+/- 1.4 degees from the optical axis). I can see from the pointing (CK) SPICE kernels for the last few days that they are indeed periodically slewing the ONC across the position of Mars and Phobos/Deimos. Here's one predicted view from a few days ago:



The targets are in the FOV for about a minute. I gather from the paper that the intent is to have Mars outside the FOV for the science observations.
Bob Shaw
From the MRO website:

http://mars.jpl.nasa.gov/mro/mission/sc_instru_optical.html

"Optical Navigation Camera

This camera is being tested for improved navigation capability for future missions. If it performs well, similar cameras placed on orbiters of the future would be able to serve as high-precision interplanetary "eyes" to guide incoming spacecraft as they near Mars.

From 30 days to 2 days prior to Mars Orbit Insertion, the spacecraft will collect a series of images of Mars' moons Phobos and Deimos. By comparing the observed position of the moons to their predicted positions, relative to the background stars, the mission team will accurately determine the position of the orbiter in relation to Mars.

While not needed by Mars Reconnaissance Orbiter to navigate to Mars, the data from this experiment will be used to demonstrate that this technique can be used by future spacecraft to ensure their accurate arrival. Accuracy is important to some future landers and rovers that will need extremely precise navigation at Mars arrival to get to their landing sites safely."

So, some interesting images of the moons, perhaps?

Bob Shaw
jmknapp
I made an animation of the approach through the first orbit:

MRO approach movie (5.7MB MPG file)

It's from the point of view of a (fictitious) nadir-pointing camera with the same FOV (1.14 degrees) as HiRISE.
djellison
Given the addition of some post-moi-pre-aerobraking imaging, at what appears to be between about 0000 and 0600 on the 15th of March - any idea on a nadir target for that sort of time?

Doug
jmknapp
QUOTE (djellison @ Feb 16 2006, 10:46 AM) *
Given the addition of some post-moi-pre-aerobraking imaging, at what appears to be between about 0000 and 0600 on the 15th of March - any idea on a nadir target for that sort of time?

Doug


Looks like it's the north polar ice cap. Here's the view midway in that interval (+ marks the nadir point):



Note that the FOV above is 5 degrees. CTX has an FOV 0f 6 degrees; HiRISE 1.14 degrees.
Sunspot
I kept reading that they wouldn't be doing any imaging until after aerobraking was complete.. this is good news.
mcaplinger
QUOTE (jmknapp @ Feb 16 2006, 09:00 AM) *
Looks like it's the north polar ice cap. Here's the view midway in that interval (+ marks the nadir point):


Try looking (hint, hint) closer to 6:00 UTC.
jmknapp
QUOTE (mcaplinger @ Feb 16 2006, 12:34 PM) *
Try looking (hint, hint) closer to 6:00 UTC.


Hmmm... here is the view at 0600:



Wondering what you are hinting at--perhaps this is targeted after one of the proposed Phoenix landing sites? The subpoint above is 75N 141W.
helvick
QUOTE (jmknapp @ Feb 16 2006, 06:03 PM) *
Wondering what you are hinting at--perhaps this is targeted after one of the proposed Phoenix landing sites? The subpoint above is 75N 141W.

Possibly - I had a placeholder for Phoenix @ 70N 120W but I'm not sure where I got that from. I didn't think the precise landing site had been chosen yet though.
Phil Stooke
It wouldn't be targeted, just whatever they are seeing as they pass by.

Phil
babakm
Some imaging of Phoenix candidate site D is on the MSSS site (roughly 71N 115-120W). The closest image I could find to 75N 141W is this one, but your nadir looks like it's ~180 degrees away from the projection here. Different coord systems?
RNeuhaus
Below is the Sout Pole Cap that looks different than the Nort Pole Cap. The MRO will orbit around poles?



A much better resolution and visibilty is below:


This is the south polar cap of Mars as it appeared to the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) on April 17, 2000. In winter and early spring, this entire scene would be covered by frost. In summer, the cap shrinks to its minimum size, as shown here. Even though it is summer, observations made by the Viking orbiters in the 1970s showed that the south polar cap remains cold enough that the polar frost (seen here as white) consists of carbon dioxide. Carbon dioxide freezes at temperatures around -125° C (-193° F). Mid-summer afternoon sunlight illuminates this scene from the upper left from about 11.2° above the horizon. Soon the cap will experience sunsets; by June 2000, this pole will be in autumn, and the area covered by frost will begin to grow. Winter will return to the south polar region in December 2000. The polar cap from left to right is about 420 km (260 mi) across

Rodolfo
brianc
A nice article about the MRO HIRISE camera system here

http://www.phim.unibe.ch/pig/HiRISE_IAF55.pdf
mcaplinger
QUOTE (jmknapp @ Feb 16 2006, 10:03 AM) *
Wondering what you are hinting at--perhaps this is targeted after one of the proposed Phoenix landing sites? The subpoint above is 75N 141W.


I think your software is confused, or ours is. What SPICE kernel are you using?
jmknapp
QUOTE (mcaplinger @ Feb 16 2006, 05:14 PM) *
I think your software is confused, or ours is. What SPICE kernel are you using?


Could be. Here are the kernels I'm using:

CK:
'$KROOT/ck/DESAT_MOI_sc_20060103171803.bc',

SPK:
'$KROOT/spk/spk_c_tcm1-od006_050812_060315_p-v1.bsp',
'$KROOT/spk/spk_moi_lowperf_t2_051123_060320_p-v1.bsp',
'$KROOT/spk/spk_moi_ideal_051123_060320_p-v1.bsp',
'$KROOT/spk/spk_moi_highperf_t1_051123_060320_p-v1.bsp',

I notice there's a big difference whether highperf, ideal or lowperf is used, so maybe that's the difference. The projection above uses highperf (since it's the last listed in the config file).
mcaplinger
QUOTE (jmknapp @ Feb 16 2006, 02:42 PM) *
I notice there's a big difference whether highperf, ideal or lowperf is used, so maybe that's the difference. The projection above uses highperf (since it's the last listed in the config file).


We were doing this planning several weeks ago, so the kernel I used was from mid-January. In those kernels, we were near periapsis at 6:00 UTC. Looks like we're looking at some replanning if the MOI performance makes this much difference. I would try rerunning with ideal and see what that looks like.

BTW, what software are you using for this?
jmknapp
QUOTE (mcaplinger @ Feb 16 2006, 06:31 PM) *
We were doing this planning several weeks ago, so the kernel I used was from mid-January. In those kernels, we were near periapsis at 6:00 UTC. Looks like we're looking at some replanning if the MOI performance makes this much difference. I would try rerunning with ideal and see what that looks like.

BTW, what software are you using for this?


Hmmm... using the "ideal" kernel gives periapsis on 15MAR2006 at 06:24UTC, 399km, at 67S 28E, although it's on the night side so the picture is dark. Pretty big difference there.

The software I'm using is a C program that I wrote to use the CSPICE library--so there could be a bug or three there. The same program works pretty well with Cassini, but at least in that case I have actual images to compare against for testing. Choice of kernels seems to be a big factor.

One kernel tells a cautionary tale:

spk_nomoi_051123_060320_p-v1.bsp

No MOI--gulp! That pessimistic kernel gives this view on 15MAR:

mcaplinger
QUOTE (jmknapp @ Feb 16 2006, 06:00 PM) *
Hmmm... using the "ideal" kernel gives periapsis on 15MAR2006 at 06:24UTC, 399km, at 67S 28E, although it's on the night side so the picture is dark. Pretty big difference there.

The software I'm using is a C program that I wrote to use the CSPICE library--so there could be a bug or three there. The same program works pretty well with Cassini, but at least in that case I have actual images to compare against for testing. Choice of kernels seems to be a big factor.


That result sounds pretty close to ours, so I'd say your code is working well. Those kernels just appeared on the NAIF website and I don't know what sort of burn performance differences they represent; it would surprise me if plausible burn variations would change the orbit timing so much.
Bob Shaw
QUOTE (mcaplinger @ Feb 17 2006, 04:05 AM) *
That result sounds pretty close to ours, so I'd say your code is working well. Those kernels just appeared on the NAIF website and I don't know what sort of burn performance differences they represent; it would surprise me if plausible burn variations would change the orbit timing so much.



Guys, can you *please* work out whoever is right, you're beginning to (gulp) worry me! MOI has already eaten several pretty toys...

Bob Shaw
djellison
Thing is - only a tiny tiny change in the altitiude at MOI, and the duration of MI will produce quite a large change at aphelion (it's a very eliptical orbit) and so a tiny fraction of a change to either of those numbers, will put quite a different bit of Mars under the spacecraft 5 days later smile.gif

Doug
AlexBlackwell
QUOTE (Bob Shaw @ Feb 17 2006, 12:18 PM) *
Guys, can you *please* work out whoever is right, you're beginning to (gulp) worry me! MOI has already eaten several pretty toys...

You think Mike might be using metric figures, while jmknapp is using English units?

Hmm. That sounds vaguely familiar.
jmknapp
QUOTE (AlexBlackwell @ Feb 17 2006, 01:13 PM) *
You think Mike might be using metric figures, while jmknapp is using English units?

Hmm. That sounds vaguely familiar.


I tend to prefer pixels per fortnight.

Be that as it may, any non-hyperbolic insertion orbit that doesn't intersect the surface is a good one.
AlexBlackwell
QUOTE (jmknapp @ Feb 17 2006, 06:28 PM) *
Be that as it may, any non-hyperbolic insertion orbit that doesn't intersect the surface is a good one.

That might be why the MRO mission designers baselined for aerobraking instead of lithobraking tongue.gif
elakdawalla
QUOTE (AlexBlackwell @ Feb 17 2006, 10:34 AM) *
That might be why the MRO mission designers baselined for aerobraking instead of lithobraking tongue.gif

I was going to crack that joke but I thought "Naw -- it's too old and tired." I guess no joke is too old and tired for an academic tongue.gif

--Emily
AlexBlackwell
QUOTE (elakdawalla @ Feb 17 2006, 06:36 PM) *
I was going to crack that joke but I thought "Naw -- it's too old and tired." I guess no joke is too old and tired for an academic tongue.gif
--Emily

Yeah, the joke was pretty stale.

In fact, as Mike has pointed out over the years, the public has gotten an incomplete if not distorted view of the MCO/MPL/DS2 losses, mainly that the root causes, especially of the MCO loss, can't be simply described as "Oh, they screwed up because they didn't know the difference between metric and English units."

For balance, I would also recommend the following:

Euler, Edward A., Steven D. Jolly, and H.H. Curtis; The Failures of the Mars Climate Orbiter and Mars Polar Lander: A Perspective From the People Involved; AAS 01-074, 24th Annual AAS Guidance and Control Conference, Breckenridge, CO, January 31-February 4, 2001.

A few years ago, Steve Jolly (of LMAO) also sent me some PowerPoint slides, prepared, I believe, for a subsequent conference. These offered some nice perspective, as well as being pretty instructive.

* EDIT - Before "[f]or balance" above, I should have inserted "In addition to the 'official' mishap investigation reports, which can downloaded, among other places, here, as well as the popular press coverage (of varying degrees of accuracy),..."
Phil Stooke
Emily: "I guess no joke is too old and tired for an academic"

And no academic is too old and tired for a good joke.

Phil
mcaplinger
QUOTE (AlexBlackwell @ Feb 17 2006, 10:13 AM) *
You think Mike might be using metric figures, while jmknapp is using English units?


Very funny, Alex. smile.gif If it makes anyone feel better, I don't have anything to do with planning MOI.

jmknapp has performed a valuable public service by highlighting that those three kernels produce significant orbital timing changes; I hadn't appreciated that the MOI performance could induce that large a change, but now we're prepared. We weren't given any context about what those kernels might mean -- they just showed up on the NAIF website. They may be for training purposes, or they may be physically realistic.
lyford
QUOTE (Phil Stooke @ Feb 17 2006, 10:58 AM) *
Emily: "I guess no joke is too old and tired for an academic"

And no academic is too old and tired for a good joke.

Phil

And I was going to crack that joke.....
It's getting to the point where I log on to UMSF and just nod in assent to almost every post tongue.gif
AlexBlackwell
QUOTE (mcaplinger @ Feb 17 2006, 07:50 PM) *
Very funny, Alex. smile.gif If it makes anyone feel better, I don't have anything to do with planning MOI.

I couldn't resist the tweak, Mike, especially since I know the way the MCO/MPL/DS2 losses were reported has grated on you. It's not the same, though, as needling Bruce. Now that is fun tongue.gif

QUOTE (mcaplinger @ Feb 17 2006, 07:50 PM) *
jmknapp has performed a valuable public service by highlighting that those three kernels produce significant orbital timing changes; I hadn't appreciated that the MOI performance could induce that large a change, but now we're prepared. We weren't given any context about what those kernels might mean -- they just showed up on the NAIF website. They may be for training purposes, or they may be physically realistic.

Is this similar to the slight differences between MSSS-generated and JPL-designed targeting boxes that were evident early in MOC campaign? If I remember correctly, sometimes your orbit predicts disagreed with JPL's.
djellison
QUOTE (AlexBlackwell @ Feb 17 2006, 08:06 PM) *
It's not the same, though, as needling Bruce. Now that is fun tongue.gif


Now that's actually a requirement for membership here, it's not a matter of humour - it's part of the process cool.gif

Doug
jmknapp
QUOTE (mcaplinger @ Feb 17 2006, 02:50 PM) *
jmknapp has performed a valuable public service by highlighting that those three kernels produce significant orbital timing changes; I hadn't appreciated that the MOI performance could induce that large a change, but now we're prepared. We weren't given any context about what those kernels might mean -- they just showed up on the NAIF website. They may be for training purposes, or they may be physically realistic.


FWIW, here's the difference between the three kernels in terms of altitude. Looks like they are very different. Not sure of the context as you say--both high perf and low perf have shorter periods than ideal.

djellison
Being VERY unscientific, approx speed at periareion using Orbiter with these apareion's....

10000km - 4330 m/sec
18000km - 4460 m/sec
28000km - 4590 m/sec
38000km - 4650 m/sec
45000km - 4670 m/sec

So to vary between 28000 and 45000 is only a 80ish m/sec difference, in an MOI burn of I believe roughly 1000 m/sec over 25 minutes - so +/- 40m/sec is about a 4% error, or 1 minute of the burn

200 x 400km orbit is approx 3520 - 3320 m/sec ish -so aerobraking is giving us another 1000 m/sec of delta V.

All figures very VERY roughly done in orbiter.

Doug
AlexBlackwell
Feb. 17, 2006

Dwayne Brown/Erica Hupp
Headquarters, Washington
(202) 358-1726\1237

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
(818) 354-6278

MEDIA ADVISORY: M06-029

NASA ANNOUNCES MARS MISSION BRIEFING

NASA will brief news media about the Mars Reconnaissance Orbiter
mission at 1 p.m. EST, Friday. The event is in NASA's auditorium, 300
E Street SW, Washington.

The NASA spacecraft is scheduled to arrive at Mars on March 10, 2006.
It will provide more information about the planet than all previous
NASA Mars missions combined. Participants will address mission goals
and the sequence of events necessary to successfully place the
vehicle into orbit around Mars.

Briefing Participants: Doug McCuistion, NASA Mars Exploration Program
Director, NASA Headquarters; Michael Meyer, NASA Mars Lead Scientist,
NASA Headquarters; James Graf, Mars Reconnaissance Orbiter Project
Manager, Jet Propulsion Laboratory, Pasadena, Calif.; Bob Berry,
Director, Space Exploration Systems, Lockheed Martin Space Systems
Co., Denver.

The briefing will air live on NASA TV, and the panel will take
questions from reporters at participating NASA centers. To ask phone
questions, reporters must call Jet Propulsion Laboratory media
relations by 5 p.m. EST, Tuesday at: (818) 354-5011 to obtain a
call-in number. To view a live webcast of the event and for more
mission information on the Web, visit: http://www.nasa.gov/mro

NASA TV's Public, Education and Media channels are available on an
MPEG-2 digital C-band signal accessed via satellite AMC-6, at 72
degrees west longitude, transponder 17C, 4040 MHz, vertical
polarization. In Alaska and Hawaii, they're on AMC-7 at 137 degrees
west longitude, transponder 18C, at 4060 MHz, horizontal
polarization. For digital downlink information on the Web, visit:
http://www.nasa.gov/ntv


-end-
Bob Shaw
The way I see it, almost *any* orbit is better than an unplanned landing mission. And I was, originally, really trying *not* to be cruel about the MCO trajectory, honest! I didn't *need* to be cruel, not with you lot aboard...

Bob Shaw
AlexBlackwell
QUOTE (Bob Shaw @ Feb 17 2006, 10:46 PM) *
I didn't *need* to be cruel, not with you lot aboard...

Hey, you forgot to include the appropriate emoticon. Or did you forget? blink.gif
RNeuhaus
QUOTE (AlexBlackwell @ Feb 17 2006, 03:06 PM) *
I couldn't resist the tweak, Mike, especially since I know the way the MCO/MPL/DS2 losses were reported has grated on you. It's not the same, though, as needling Bruce. Now that is fun tongue.gif

Also don't forget of Mars orbiter Nozomi, the japanese probe passed by 1000km above the Martian surface on December 14 and escaped from the gravitational sphere of Mars on December 16 to continue on traveling along the orbit around the sun. due to unrecoverable malfunction injection. sad.gif

No more jokes of that kind, no matter of what old is that but not one as a good prediction mad.gif . MRO is a very nice toy!

Rodolfo
ElkGroveDan
QUOTE (jmknapp @ Feb 17 2006, 09:39 PM) *
FWIW, here's the difference between the three kernels in terms of altitude. Looks like they are very different. Not sure of the context as you say--both high perf and low perf have shorter periods than ideal.

OK now that we have figure out that there are problems with the Colonel's spices, the original question seems to have been lost. What was Mike referring to when he said "Try looking (hint, hint) closer to 6:00 UTC."?
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