LRO will spend the rest of its existence in a Moon-centered universe. This diagram illustrates that point of view. (Note that the distances between Earth, Moon, and Sun are not to scale, nor are their sizes.)
At present, Earth is in the lower left (Quadrant 2). The Sun is in the clear wedge at the right. Whenever the Sun is in Gemini (late June through late July), or in Sagittarius (six months later), LRO will receive sunlight throughout its entire lunar orbit, unblocked by the Moon. Earth is continuously visible to the Orbiter when located in Sagittarius (at the left) or Gemini (at the right).
The "ascending/descending" notation refers to LRO's path upward, out of the plane of the diagram (towards the viewer) or downward into the plane of the diagram. Readers with a knowledge of physics or mathematical notation will recognize the vector ("arrow") pointing out of the Moon towards the left. Align your right-hand thumb with the arrow, and then the rest of your fingers will point in the direction of orbital travel. (The "right-hand rule.")
"Eclipse Season" refers to times of the year when LRO will have its view of the Sun blocked by the Moon, ranging from moments (when the Sun is near the clear wedges) to 48 minutes (when the Sun is at the top or bottom of the diagram).
I think the diagram may be in error by using the term "lunar solstice." I think it should be "lunar equinox" (when the Sun is over the Moon's equator, as happens twice a year).
Occasionally, Earth will block all or part of the Sun as seen from LRO. Those events are what we on Earth see as lunar eclipses, when the Moon passes through Earth's shadow.
We've got a few of those coming up this year: July 7, August 6, and December 31. The first two are called "penumbral" eclipses because Earth will not completely block the Sun as seen from anywhere on the Moon. The latter event will be a "partial" eclipse because the Sun will be completely blocked, but only as seen from a part of the Moon (in this case, a relatively small area near the south pole).
Next year will have another partial (June 26, when the northern half of the Moon sees Earth completely cover the Sun) and a "total eclipse," when an observer anywhere on the lunar surface would see the entire Sun blocked for a time. That one is on December 21, lasting 83 minutes. Our power and thermal specialists designed LRO to withstand those conditions, but we will also take special steps to protect the spacecraft during that extended period of darkness, which will last longer than our usual worst-case 48 minutes (twice a month) caused by orbiting over the Moon's midnight longitude.
Note that June and December are when LRO's view of the Sun is perpetually unobstructed by the Moon. That means the shadows caused by Earth will not be extended in duration by LRO then having to pass into the Moon's shadow.
I believe this arrangement was intentionally made by our selection of launch date and lunar intercept point.
Friday, June 26, 2009
LRO's Orbit
Our burn completed successfully.
LRO's orbit passes over the Moon's north and south poles and is described as "inertially frozen." That means that it is unchanging in orientation with respect to the stars. The Moon rotates below, once each month, the Sun will circle it once a year, and Earth will circle it once a month, but the stars will remain fixed in LRO's sky.
I think the easiest way to picture this is:
Whenever the Moon is in the constellation Gemini, we see LRO orbiting the lunar disk counter-clockwise. When the Moon is at the opposite side of its orbit (180 degrees away in the sky, in the constellation Sagittarius), again we see LRO orbiting the lunar disk, but clockwise.
90 degrees to the east of Gemini is the constellation Virgo. When the Moon is there, LRO's orbit passes from south to north across the middle of the lunar disk as we see it. During half of LRO's 113-minute orbit, we can't see it from Earth because it's blocked by the Moon.
On the opposite side of the sky from Virgo is Pisces. When the Moon is there, LRO passes from north to south across the middle of the Moon's disk.
In between those four locations, you can interpolate where LRO's path would cross in front of or behind the Moon.
LRO's orbit passes over the Moon's north and south poles and is described as "inertially frozen." That means that it is unchanging in orientation with respect to the stars. The Moon rotates below, once each month, the Sun will circle it once a year, and Earth will circle it once a month, but the stars will remain fixed in LRO's sky.
I think the easiest way to picture this is:
Whenever the Moon is in the constellation Gemini, we see LRO orbiting the lunar disk counter-clockwise. When the Moon is at the opposite side of its orbit (180 degrees away in the sky, in the constellation Sagittarius), again we see LRO orbiting the lunar disk, but clockwise.
90 degrees to the east of Gemini is the constellation Virgo. When the Moon is there, LRO's orbit passes from south to north across the middle of the lunar disk as we see it. During half of LRO's 113-minute orbit, we can't see it from Earth because it's blocked by the Moon.
On the opposite side of the sky from Virgo is Pisces. When the Moon is there, LRO passes from north to south across the middle of the Moon's disk.
In between those four locations, you can interpolate where LRO's path would cross in front of or behind the Moon.
Today's Burn
Nearing today's orbit-adjustment burn, set for 8:25 AM EDT. Tomorrow morning will be the final one to get us into the commissioning orbit.
Around 6 this morning we did a reaction wheel momentum unload (entering "Delta-H Mode"), using thrusters to slow down the wheel speeds to keep them below specified thresholds.
Our colleagues at Arizona State University (home of the science operations center for the LRO Camera (LROC)) have posted a diagram showing where LRO is:
I've had some trouble on my home computer with it not showing the LRO path or position, but it displays fine on my work computer.
The projection of the lunar surface may be confusing to most readers. The far left and far right three-grid-wide segments are the far side (never seen from Earth) and the center six-square-wide segment is the near side, distinctive for its maria (the dark lava-bed plains, mostly absent from the far side). North is up.
Just a moment ago we reacquired contact with the Orbiter. This was my first shift during which the Orbiter passed behind the Moon. It emerged about 20 minutes later.
Wednesday, June 24, 2009
LRO and the Moon
I kept checking after sunset tonight to try to get my first glimpse of the Moon after LRO's LOI, but clouds covered all but a small strip of sky along the horizon. It wasn't until late (9:43 PM EDT, to be exact) that I finally spotted it in that strip from my mom's apartment window. I called my colleague Scott Walling (manning the flight software station in the LSR) to tell him to look for it when he went off shift at 10, and then we went outside to get a better view for ourselves and talked for a while.
If I'd thought ahead, I would've asked my Flight Dynamics colleagues where LRO was in its orbit at particular times. There's no chance of seeing it, but it's cool to have a rough idea of where it should be while you're looking at the Moon. I do know that LRO is orbiting the Moon counter-clockwise as we currently see it. The orbit (as of tonight) takes it as close as about 120 miles above the south pole, and as far as a thousand above the north. That would be about half the width of the lunar disk away from the northern edge.
As is often the case when the Moon is a crescent, we could faintly see some of the surface features on its night side. That's caused by Earthlight. A nearly full Earth (four times larger than the Moon appears in our sky) is shining in the Moon's (and LRO's) sky now, with only a sliver of darkness along its eastern edge. (The phase of Earth's disk as seen from the Moon is always a mirror image of the Moon's phase as we see it, with light and dark areas reversed.)
Milton
The LRO visualization lead is my friend Jennifer. She's several months pregnant with a son who will be named Noah. She and her husband are still mulling over middle names. She's been trying to find a Moon-related name, but most of those are feminine (e.g., Selena). Otherwise she's thinking of using her grandfather's name, Milton.
I pointed out that there's a crater on the Moon named Milton, so she was happy that her problem might be solved.
Unfortunately I learned later that the name was never officially approved by the International Astronomical Union! There is a crater named after John Milton on the planet Mercury, but that won't help Jennifer's cause.
Noah's big sister is named Marleyani, owed in part to Jennifer's husband being a fan of reggae performer Bob Marley. I love the sound of that name.
I pointed out that there's a crater on the Moon named Milton, so she was happy that her problem might be solved.
Unfortunately I learned later that the name was never officially approved by the International Astronomical Union! There is a crater named after John Milton on the planet Mercury, but that won't help Jennifer's cause.
Noah's big sister is named Marleyani, owed in part to Jennifer's husband being a fan of reggae performer Bob Marley. I love the sound of that name.
Review of Yesterday's Performance
Tonight at 11 PM EDT, NASA TV showed a replay of Tuesday morning's one-hour LRO LOI television coverage. The program was shown in both the MOC and LSR...our first chance to see how we came across on TV.
Darn it, I forgot to emote! My chance to be spotted by a talent agent has fallen to shreds...again.
The burn went so well that there wasn't much to show until it ended. My colleague Mike Blau commented to Bruce Trout about halfway through, "This is the most boring sim we've done."
Being up all night probably kept me pretty low key. Tension was probably the primary sensation I had through most of the burn. Not a lot, but some. Relief and a bit of incredulity came after it ended. A mix of other strong (good) emotions surfaced (mostly showing, others held back a bit as necessary) when I celebrated with the rest of the team.
Here's the big picture: my notes indicate that I first met with Mike Blau and Rick Saylor, the Ground Systems and Operations lead (and last night's flight director) when I joined LRO on March 1, 2007. The main question posed to me at that meeting...if an anomaly should impact LRO during its 3-5 day lunar cruise phase, can you create a flight software "patch" (a change to code or data) fast enough to fix the problem, so the LOI burn could take place as planned?
I still have a message I later wrote to management about this, excerpted here: "[They want to know if we can devise a ] "Lunar Cruise Emergency Patch Procedure." (Lunar Cruise is the five-day trip from Earth to the Moon...a mission phase that could lead to loss of mission if something prevents the Lunar Orbit Insertion Burn from going correctly at the end of Lunar Cruise, in which case the spacecraft will pass by the Moon and out into deep space.) I informed [them] that in principle we can accelerate our process, but the result would be increased risk introduced from each stage of the process. Some anomalies could take longer than five days to even understand, much less devise a fix for. I strongly recommended that their primary line of defense should be to test all nominal and contingency Lunar Cruise operations, and we (FSW) could provide only a secondary line of defense."
In a way, this has weighed on my mind for over two years. Finally that pressure is off now that we're safely in orbit. In another post I'll give a quick overview of what I might've done if an emergency had occurred before LOI.
Darn it, I forgot to emote! My chance to be spotted by a talent agent has fallen to shreds...again.
The burn went so well that there wasn't much to show until it ended. My colleague Mike Blau commented to Bruce Trout about halfway through, "This is the most boring sim we've done."
Being up all night probably kept me pretty low key. Tension was probably the primary sensation I had through most of the burn. Not a lot, but some. Relief and a bit of incredulity came after it ended. A mix of other strong (good) emotions surfaced (mostly showing, others held back a bit as necessary) when I celebrated with the rest of the team.
Here's the big picture: my notes indicate that I first met with Mike Blau and Rick Saylor, the Ground Systems and Operations lead (and last night's flight director) when I joined LRO on March 1, 2007. The main question posed to me at that meeting...if an anomaly should impact LRO during its 3-5 day lunar cruise phase, can you create a flight software "patch" (a change to code or data) fast enough to fix the problem, so the LOI burn could take place as planned?
I still have a message I later wrote to management about this, excerpted here: "[They want to know if we can devise a ] "Lunar Cruise Emergency Patch Procedure." (Lunar Cruise is the five-day trip from Earth to the Moon...a mission phase that could lead to loss of mission if something prevents the Lunar Orbit Insertion Burn from going correctly at the end of Lunar Cruise, in which case the spacecraft will pass by the Moon and out into deep space.) I informed [them] that in principle we can accelerate our process, but the result would be increased risk introduced from each stage of the process. Some anomalies could take longer than five days to even understand, much less devise a fix for. I strongly recommended that their primary line of defense should be to test all nominal and contingency Lunar Cruise operations, and we (FSW) could provide only a secondary line of defense."
In a way, this has weighed on my mind for over two years. Finally that pressure is off now that we're safely in orbit. In another post I'll give a quick overview of what I might've done if an emergency had occurred before LOI.
Orbit Adjustments
About an hour after my shift ends at 6 AM, LRO will perform another burn. This one will only last for 12 minutes. It's the first of four daily burns that will adjust our orbit into the profile desired during the "commissioning phase," when science instruments, the flight software, and attitude sensors will be modified, fine-tuned, and readied for the one-year exploration mission phase. When commissioning completes, LRO will be put into a circular and low (50-km) orbit that is harder (as in, consuming more fuel) to maintain than our commissioning orbit. But our science instruments require the more precise close-in orbit.
Earlier today, one of my colleagues generated the burn products for the onboard computer. About an hour ago I supervised their uplink to the Orbiter.
The four daily burns are called LOI burns, which is a misnomer. We have already "inserted" LRO into a lunar orbit with the true LOI yesterday.
Earlier today, one of my colleagues generated the burn products for the onboard computer. About an hour ago I supervised their uplink to the Orbiter.
The four daily burns are called LOI burns, which is a misnomer. We have already "inserted" LRO into a lunar orbit with the true LOI yesterday.
Strange But True
To my knowledge, only two prime-time TV series have been set on the Moon. Both were created and produced by the same man, Gerry Anderson of the United Kingdom. The first was UFO (1970-71). The second was Space: 1999 (1975-77). Although both have serious flaws, I enjoy them to some extent. The latter was a big-budget special effects show that skimped on storytelling, characterization, and drama. It (at least during the first season) tried to emulate the mind-blowing SF/mystical aura of Kubrick and Clarke's 2001: A Space Odyssey. But that's a tall order and it fell far short. I still appreciate it for being (as Star Trek was, much more successfully) a depiction of the future of humanity as cosmic explorers...essentially an extrapolation of NASA's mission. (In contrast to Star Wars and other SF that focuses primarily on conflict instead of exploration.)
Anyway...there is a strange aspect tying together LRO and Space: 1999. The show was set on "Moonbase Alpha," the commander of which was John Koenig, portrayed by future Oscar Award-winning actor Martin Landau.
Notably, one member of the Mission Operations Team for LRO happens to be named...
John Koenig.
I mentioned this to him and he was amused. He's somewhat familiar with the show. I also confirmed that he was born before the series was produced, so there's no chance he was named in homage to Commander Koenig. Otherwise that might've implied that his parents had an interest in space exploration, possibly conveyed to their son, who might then end up working in the space program. That would've made this not really a coincidence at all, although his working on a Moon mission in particular is still remarkable.
What does this "mean?" Is God brushing against our funny bones? Who knows for sure? My perspective is that we are surrounded by an almost infinite number of "details" and events, most of which are not directly interconnected. Meanwhile, our brains are superb pattern detectors. We perceive as much as we can that appears to be connected. Sometimes the patterns are valid, often not. This coincidence is, I'm pretty sure, in the latter category.
Anyway...there is a strange aspect tying together LRO and Space: 1999. The show was set on "Moonbase Alpha," the commander of which was John Koenig, portrayed by future Oscar Award-winning actor Martin Landau.
Notably, one member of the Mission Operations Team for LRO happens to be named...
John Koenig.
I mentioned this to him and he was amused. He's somewhat familiar with the show. I also confirmed that he was born before the series was produced, so there's no chance he was named in homage to Commander Koenig. Otherwise that might've implied that his parents had an interest in space exploration, possibly conveyed to their son, who might then end up working in the space program. That would've made this not really a coincidence at all, although his working on a Moon mission in particular is still remarkable.
What does this "mean?" Is God brushing against our funny bones? Who knows for sure? My perspective is that we are surrounded by an almost infinite number of "details" and events, most of which are not directly interconnected. Meanwhile, our brains are superb pattern detectors. We perceive as much as we can that appears to be connected. Sometimes the patterns are valid, often not. This coincidence is, I'm pretty sure, in the latter category.
The Smallest of Regrets
If we had launched as planned on June 17 instead of 18 (we rescheduled to give shuttle Endeavour its last opportunity to launch to the International Space Station this month), we would've arrived at the Moon on a Monday instead of a Tuesday. There's a certain poetry in arriving at a destination on a day of the week that's named after that destination.
At least we were able to go to the Moon in the month of June, giving amateur poets and songwriters a break in finding easy rhymes.
At least we were able to go to the Moon in the month of June, giving amateur poets and songwriters a break in finding easy rhymes.
Orbiting
Now nearing the end of our first day in lunar orbit. We had a surprise just before noon EDT on Tuesday. As described in the LRO blog, the Orbiter automatically protected itself (entering SunSafe Mode) because a flight software "actionpoint" (AP22) had evaluated a sizeable discrepancy between how the spacecraft was oriented and where it expected it should be (specifically an angle greater than 25 degrees).
Actionpoints are defined in a flight software "task" called "Limit Checker," which monitors specified onboard sensor data against thresholds that we set in order to protect various onboard systems, including the spacecraft itself. When an actionpoint trips, it triggers a predefined sequence of commands intended to respond properly (as best as can be predicted ahead of time) to the detected situation.
What caused the attitude discrepancy? Our Guidance, Navigation & Control (GN&C) colleagues believe that one of the star trackers was busy detecting stars, identifying them, and using that information to return attitude knowledge to the onboard computer when the Moon impinged on its field of view. The tracker is designed not to be confused by this event, but perhaps evaluated sunlit mountain peaks as stars and made a "match" that indicated a star field in another part of the sky, returning a very different spacecraft attitude than the true one. The Limit Checker caught the problem based on the Attitude Control task's overall attitude knowledge (which uses gyros and sun sensor information in addition to star tracker data).
After the circumstances of this incident were established by the LRO team, the Orbiter was commanded back to its usual attitude-control mode ("Observing Mode"). For the rest of the day, star trackers were intentionally commanded out of the control loop whenever the Moon's limb came near the field of view. Instead, the gyros were used at those times.
A few hours ago, "Kalman Filter" control was enabled for the first time. This will prevent the problem from happening again. Onboard ephemeris data will be used in conjunction with the star tracker to indicate when the star tracker will be blocked by the Moon (or Earth) and not be used for attitude knowledge.
The reason KF control wasn't used earlier was that various settings were still requiring fine tuning.
Having said all this, I should add a disclaimer that I am not an attitude-control specialist and my description should be considered a "rough draft" with no guarantees of complete accuracy. I have included my inferences with tentative findings that may not be the complete story. I hope to convey the general aspects of spacecraft attitude control however.
Tuesday, June 23, 2009
Incoming
Here are a couple of photos illustrating the incoming Moon last night. The one on the left was taken at around midnight local, the other around 3 AM. Mare Orientale is the dark spot near the center of the lunar image.
Success!
The burn completed without problems and LRO is now in lunar orbit!
http://www.spaceflightnow.com/atlas/av020/090623loi.html
Applause and congratulations spread across the MOC and LSR afterwards. Champagne and Moon Pies were distributed to all. Cameras were flashing away.
Our fellow payload, LCROSS, along with the Centaur booster rocket, is currently swinging past the Moon to redirect its trajectory into a favorable one for impact in October.
My adrenaline is wearing off quickly so I will close for now.
A few more days of orbit-adjustment burns will be required.
http://www.spaceflightnow.com/atlas/av020/090623loi.html
Applause and congratulations spread across the MOC and LSR afterwards. Champagne and Moon Pies were distributed to all. Cameras were flashing away.
Our fellow payload, LCROSS, along with the Centaur booster rocket, is currently swinging past the Moon to redirect its trajectory into a favorable one for impact in October.
My adrenaline is wearing off quickly so I will close for now.
A few more days of orbit-adjustment burns will be required.
Here we go
My final posting before the burn, now less than an hour away.
NASA TV coverage will begin at 5:30, running until 6:30 AM EDT.
My colleagues Mike Blau and Bruce Trout are at the FSW station monitors. I've taken my place at the position behind them.
NASA TV coverage will begin at 5:30, running until 6:30 AM EDT.
My colleagues Mike Blau and Bruce Trout are at the FSW station monitors. I've taken my place at the position behind them.
Salutes
Since I'm saluting people here, I'll add one for my older brother, Mark, who got me interested in astronomy and space flight from early on. I'm told my first word was "Moon," probably learned from him.
Also, looking back over my educational and professional career, there's no question that I prospered most whenever there was a special someone at my side (and there's no question that such prosperity is harder to find without someone, I might add). Roberta Yates and Joy Conrad are remarkable women who changed my life for the better, both dear to me though we went separate ways. Both are following this blog so I will salute them too!
(BTW, the photo of Joy shows her demonstrating a Van de Graaff generator...her hair doesn't naturally stand on end.)
Coincidentally, Joy's husband, Steve King, also works on a Moon-related project. He's lead mechanical engineer at Johnson Space Center in Houston for the Orion capsule's access hatch.
Finally, I want to salute someone who shall remain nameless but has been my "muse" in recent months. She may be following this blog as well.
Also, looking back over my educational and professional career, there's no question that I prospered most whenever there was a special someone at my side (and there's no question that such prosperity is harder to find without someone, I might add). Roberta Yates and Joy Conrad are remarkable women who changed my life for the better, both dear to me though we went separate ways. Both are following this blog so I will salute them too!
(BTW, the photo of Joy shows her demonstrating a Van de Graaff generator...her hair doesn't naturally stand on end.)
Coincidentally, Joy's husband, Steve King, also works on a Moon-related project. He's lead mechanical engineer at Johnson Space Center in Houston for the Orion capsule's access hatch.
Finally, I want to salute someone who shall remain nameless but has been my "muse" in recent months. She may be following this blog as well.
Riding Along
Onboard LRO is a microchip containing about 1.7 million names of those who submitted them online. "Send Your Name to the Moon" was jointly sponsored by NASA, The Planetary Society, and Johns Hopkins Applied Physics Lab about a year ago.
Among the names is my Uncle Ruso, who passed away after a long illness last year. I entered his name and mailed his certificate to him before he passed away. Also the names of a number of my friends (too many) who died young are onboard: Paul DeHaven, Tim Warner, Catherine Livingston, and Gregory Elbo. I added the name of my father, historian Charles Snell, about a year after he died.
Also on the chip is poetry submitted by LRO team members. My favorite is written by LRO itself (okay...actually ghost-written by my colleague Maxine "Max" Saylor, a member of the Mission Operations Team and a TC (Test Conductor) during LRO Integration and Testing):
TCs
by LRO
I patiently wait day by day
For one of you to come and play
You give me life through day and night
You touch some keys to give me flight
From breadboards you’ve helped me grow
You’ve nursed me through my days of woe
To you, TCs, I will be true
'Cause no one knows me like you do
Keep those sys engineers away
Or, I swear, I'll fire my NEAs [non-explosive actuators]
I'm on my way to the Moon
I'll be leaving you, my family, soon
If anything happens to me in space
I know you'll be my saving grace
Farewell to Bob, Mike, Dan and Jeff
Adieu to you Rich, Max, and Tim
Jabari, Mehul and George, fare thee well...
Thanks for the memories.
Among the names is my Uncle Ruso, who passed away after a long illness last year. I entered his name and mailed his certificate to him before he passed away. Also the names of a number of my friends (too many) who died young are onboard: Paul DeHaven, Tim Warner, Catherine Livingston, and Gregory Elbo. I added the name of my father, historian Charles Snell, about a year after he died.
Also on the chip is poetry submitted by LRO team members. My favorite is written by LRO itself (okay...actually ghost-written by my colleague Maxine "Max" Saylor, a member of the Mission Operations Team and a TC (Test Conductor) during LRO Integration and Testing):
TCs
by LRO
I patiently wait day by day
For one of you to come and play
You give me life through day and night
You touch some keys to give me flight
From breadboards you’ve helped me grow
You’ve nursed me through my days of woe
To you, TCs, I will be true
'Cause no one knows me like you do
Keep those sys engineers away
Or, I swear, I'll fire my NEAs [non-explosive actuators]
I'm on my way to the Moon
I'll be leaving you, my family, soon
If anything happens to me in space
I know you'll be my saving grace
Farewell to Bob, Mike, Dan and Jeff
Adieu to you Rich, Max, and Tim
Jabari, Mehul and George, fare thee well...
Thanks for the memories.
T-minus 3 hours
Preparations for LOI continue. I was involved briefly when the burn-related Absolute-Time [command] Sequence (ATS) was "committed" to EEPROM in the onboard computer. The LOI burn will be controlled by an onboard command sequence, just as the Mid-Course Correction was. ("Absolute-time" refers to the commands being executed at specific times, for example, the burn start will be commanded at 09:47:18 Universal Time on Day 174 of 2009.)
The reason for committing the ATS to EEPROM is in case the computer should experience an unexpected reset (like booting a home computer) before LOI begins. In that case, we can recover more quickly if the ATS has been stored in EEPROM, the contents of which survive resets. We can then copy the ATS into RAM (where our executable code and data reside), rather than having to re-upload it from the ground. It gives us an extra (though small) margin of saved time in case of emergency.
The reason for committing the ATS to EEPROM is in case the computer should experience an unexpected reset (like booting a home computer) before LOI begins. In that case, we can recover more quickly if the ATS has been stored in EEPROM, the contents of which survive resets. We can then copy the ATS into RAM (where our executable code and data reside), rather than having to re-upload it from the ground. It gives us an extra (though small) margin of saved time in case of emergency.
The Moon Looms Large
Our visualization screen shows the Moon growing larger by the minute. I've asked our visualization lead to convey a screen capture to the deputy project manager for posting on the LRO blog.
A last-quarter Moon is approaching LRO. Half of the near side (the face that perpetually faces Earth) and half of the far side is visible, with the latter being illuminated by sunlight. Most conspicuous is Mare Orientale, a large impact feature that looks like a bull's eye at the center of the lunar face. This hemisphere (western) is the "leading" edge of the Moon as it revolves around Earth.
"Orientale" means "eastern" even though it's actually western. That's because the feature was discovered and named when astronomical convention mirrored terrestrial cardinal points instead of reorienting them onto coordinate systems of other worlds.
A last-quarter Moon is approaching LRO. Half of the near side (the face that perpetually faces Earth) and half of the far side is visible, with the latter being illuminated by sunlight. Most conspicuous is Mare Orientale, a large impact feature that looks like a bull's eye at the center of the lunar face. This hemisphere (western) is the "leading" edge of the Moon as it revolves around Earth.
"Orientale" means "eastern" even though it's actually western. That's because the feature was discovered and named when astronomical convention mirrored terrestrial cardinal points instead of reorienting them onto coordinate systems of other worlds.
Sir Paul
By the way, Sir Paul McCartney is a space flight enthusiast. The last time he played a show in DC (MCI Center, Oct 8, 2005) was a couple of months after the space shuttle's "Return to Flight" following the Columbia disaster. That flight of shuttle Discovery was commanded by Lt Col Eileen Collins (previously the first-ever woman space-mission commander, during a 1999 Columbia flight), a Beatles fan who requested that the astronauts' wake-up song on their final day in orbit be "Good Day Sunshine."
McCartney mentioned this and talked a bit about the flight before he and his band started into their rendition. Meanwhile the elaborate HD screens behind them showed video from the mission...an extremely well-edited/produced visual. Kind of thrilling to experience.
This is a good excuse for me to salute my older sister Nancy, who was at that concert with me. She got me hooked on Beatles music from the very start. They're still my favorite band.
McCartney mentioned this and talked a bit about the flight before he and his band started into their rendition. Meanwhile the elaborate HD screens behind them showed video from the mission...an extremely well-edited/produced visual. Kind of thrilling to experience.
This is a good excuse for me to salute my older sister Nancy, who was at that concert with me. She got me hooked on Beatles music from the very start. They're still my favorite band.
Monday, June 22, 2009
Lunar Cruise Day 4
A busy day (Monday) for me...my on-console shift ended at 6 AM. Then I got a few hours sleep before tickets for Paul McCartney's Aug 1 FedEx Field show went on internet "presale" for American Express card holders. Success! I was able to get tickets on the field, albeit rather far back from the stage. Then back in to work at noon for an hour. The Lunar Orbit Insertion burn parameters were ready for conversion into onboard computer-readable form. I created the "table" load files and made sure they arrived safely at the FlatSat simulator for checkout. After I returned home to get some more sleep, the checkout completed successfully and they were uploaded to the Orbiter. About an hour ago we performed a brief "engineering burn" to confirm that the spacecraft operates as expected before we do the 40-minute burn beginning at 5:47 AM EDT on Tuesday. So far all seems to have gone extremely well in the test burn.
This evening I decided to play in my Goddard softball league team's regularly scheduled game. (Things have been going well with LRO and I have some excess adrenaline to burn off.) Unfortunately we came up on the short end of a 14-10 score. We fell behind 10-0 but then came back strong with 7 runs in one inning. I led it off with a hit, scored, and got a second hit in that inning, but a three-run deficit was as close as we got the rest of the way.
At least I got to enjoy a beautiful evening after the clouds blew through and the Sun came out. I knew the Moon was there too, but too close to the Sun to be visible. (New Moon was on Monday afternoon.) The Moon passed a bit north of the Sun, which is why we didn't have an eclipse today.
Within a day or two, a crescent Moon will emerge in the evening sky, visible in the west after sunset. Hopefully it will by then have a "moon' of its own...LRO.
Moon from STS-107 Columbia
Columbia changed the course of human spaceflight twice...in 1981 as the first reusable spacecraft, and in 2003 when its destruction led to a reassessment of exploration objectives. Ironically, one of the photos taken during the final flight of Columbia was of a last-quarter Moon:
FSW station
There are two mission patches I attached to the front of our flight software station monitors. One is a special commemorative patch for the 40th anniversary of the Apollo 11 mission next month.
The other is for STS-107, the ill-fated final flight of Space Shuttle Columbia, which burned up on re-entry on Feb 1, 2003, taking the lives of its crew: Col. Rick Husband (USAF), the commander; Cdr William McCool (USN), the pilot; mission specialists Cpt David Brown (USN), Dr. Kalpana Chawla, and Cpt Laurel Clark (USN); Lt. Col. Michael Anderson (USAF), payload commander; Col. Ilan Ramon (IAF), payload specialist.
In the wake of that tragedy emerged President Bush's "Vision for Space Exploration," realigning the US human space flight program to the Moon and Mars after decades of NASA focusing on the Shuttle and International Space Station in low Earth orbit. (No human has gone beyond low Earth orbit since Apollo 17 in 1972.)
LRO is the first step in the Vision for returning humans to the lunar surface. In a way, this entire project can be seen as a memorial to the Columbia crew. We honor their memory by blazing what he hope is a permanent trail to the Moon...not to visit in several isolated areas as Apollo did, but to explore it in its entirety, and to maintain a permanent human presence.
LRO is the first step in the Vision for returning humans to the lunar surface. In a way, this entire project can be seen as a memorial to the Columbia crew. We honor their memory by blazing what he hope is a permanent trail to the Moon...not to visit in several isolated areas as Apollo did, but to explore it in its entirety, and to maintain a permanent human presence.
An undertaking of this scale would require the support of Presidents and Congresses spanning decades. Its first test has already begun: President Obama has appointed a commission to review the Vision. Its report will be released later this year.
Lunar Cruise Day 3
Late Saturday night (and early Sunday morning), I created products for the onboard computer that compensate for the launch-vibration aftereffects on the star trackers and the gyroscopes. The flight director authorized me to proceed with creation of these products using a highly reliable (but not yet validated) input data set provided by our Attitude Ground System colleagues. We knew it was very likely that the data would be correct, so it was a sensible use of time (and would allow me to get to sleep earlier) to have me work while AGS validation was still in progress. As expected, the validation passed, and the calibration products were uplinked to the Orbiter later on Sunday morning.
Tonight I asked the AGS lead how the spacecraft is doing with its new sensor-alignment information and he reported that its attitude knowledge is essentially perfect.
Tonight I asked the AGS lead how the spacecraft is doing with its new sensor-alignment information and he reported that its attitude knowledge is essentially perfect.
Sunday, June 21, 2009
Lunar Cruise Day 3
I've decided to post images showing what the phase of the Moon is for each day. I've also re-posted a number of my earlier entries with them. These are the view from Earth (actually from a hypothetical observer at the center of a transparent Earth), courtesy of the US Naval Observatory. Keep in mind that LRO is not directly between Earth and Moon, but instead is out in front of the Moon, relatively slowly approaching the intercept point that the Moon is racing towards. So LRO has sort of a "side" view of the Moon, probably seeing past its western limb and more of the currently sunlit part of the surface.
Saturday, June 20, 2009
Visuals
The LRO blog has started posting LRO visualizations. I'd suggested to our deputy project manager and our visualization lead yesterday that screen snaps from their system could be posted on the blog. (Thanks to my friend Rob Simmon for asking me if more visuals could be provided, that got my thinking cap on.) I'd asked if a visual akin to the "in-flight airline progress display" familiar to overseas jetliner passengers could be posted from time to time, showing current positions of Earth, LRO/LCROSS, and the Moon. One of those has recently been posted.
Rob works at nearby Building 33 at Goddard (we're in 32) as the art director of NASA's Earth Observatory web site. His claim to fame is conception and creation of the familiar and near-ubiquitous "Earth's City Lights" image:
He's also famous (in my social circle) for whipping up excellent mixed drinks, although I never partake of that particular vice.
Rob and I are long-time Washington Capitals season ticket holders, still coping with the bitter aftereffects of their nemesis, the Pittsburgh Penguins, having recently won the Stanley Cup (and vanquishing the Caps in a closely-contested playoff series several weeks ago). A number of Pens and Caps fans are among the LRO team but no quarrels have broken out. Caps fans can at least rejoice that Alex Ovechkin received three awards a couple of nights ago as the National Hockey League's most valuable player and leading goal-scorer, and voted most outstanding player by all of the other players around the league.
Rob works at nearby Building 33 at Goddard (we're in 32) as the art director of NASA's Earth Observatory web site. His claim to fame is conception and creation of the familiar and near-ubiquitous "Earth's City Lights" image:
He's also famous (in my social circle) for whipping up excellent mixed drinks, although I never partake of that particular vice.
Rob and I are long-time Washington Capitals season ticket holders, still coping with the bitter aftereffects of their nemesis, the Pittsburgh Penguins, having recently won the Stanley Cup (and vanquishing the Caps in a closely-contested playoff series several weeks ago). A number of Pens and Caps fans are among the LRO team but no quarrels have broken out. Caps fans can at least rejoice that Alex Ovechkin received three awards a couple of nights ago as the National Hockey League's most valuable player and leading goal-scorer, and voted most outstanding player by all of the other players around the league.
Polling
In space flight operations parlance, "polling" occurs at critical junctures in a mission timeline. The flight director calls over the voice loop to each engineering specialist station, for example, "Power." The lead engineer at the Power station will then respond with "Go" or "No Go" (the latter with explanation). If all stations report go, the next step in the timeline is executed.
Quite by coincidence (I believe), I was polled for the first time by Gallup at noon today. Fortunately I was already awake when the call came in on my unlisted home phone. I was asked many questions about each of my white and yellow pages phone directories. What they were, how recently I'd used them, etc. My responses were essentially....never, never, never. I suppose if the power goes out and my iPhone has discharged, I would use them. I need reading glasses to read them now. I didn't back in the day when I did rely on them.
(Anytime I have a thought that ends in a question mark now, I go to my computer first. It's a good habit to develop.)
Just in case, I quickly called the phone number that appeared on my Caller ID (using my cell) while I was answering questions. The announcement gave me some confidence that I really was dealing with Gallup rather than some nefarious outfit. You can't be too careful these days.
They're in Nebraska, by the way. This particular call was from Lincoln. A number of Husker colleagues are reading this weblog, and I take this opportunity to salute you!
A salute also goes out to my friends Geoff and Susan, celebrating their 11th wedding anniversary today!
FSW station
The mission patches I attached to our flight software station monitors are visible here. On the left, the bookends of Apollo human expeditions to the lunar surface: Apollo 11 (1969) and 17 (1972). On the right, the future of human lunar exploration: Orion and Constellation, which comprises Orion and associated launch vehicles Ares I and Ares V.
The Apollo 17 patch is also in honor of Dr. Harrison Schmitt's (Apollo 17 geologist, and later US senator from New Mexico) visit to LRO's Mission Operations Center on June 3. Here's a photo of Schmitt with the LRO Mission Operations Team (MOT), the project manager, and others. (I'm not in the photo.)
Lunar Cruise: Day 2
The view from our Flight Software station. My colleague Bruce Trout is in the foreground.
The LRO blog explains the spacecraft display.
Lunar Cruise: Day 2
Photos from the Launch Support Room. The first thing you see when you enter is this magnetic sticker I put up (courtesy of my sister's husband, Bill Anselm, a fellow Goddard employee). A logo for Lockheed Martin's Orion spacecraft is on the left.
Orion is the replacement for the space shuttle. It will transport astronauts to the International Space Station and, later, to the Moon, Near-Earth Objects (asteroids), and perhaps eventually Mars.
The LRO Flight Software development team lead, Mike Blau, is seated at the right in a blue shirt and blue jeans, appropriately enough.
Friday, June 19, 2009
CRaTER and LEND
Science instruments CRaTER and LEND have been powered on.
LEND is a Russian instrument, its principal investigator is Dr. Igor Mitrofanov, who entered the Launch Support Room only a minute before the pizza arrived, so my conversation with him had to be cut short. He's busily studying telemetry from the instrument at the moment.
LEND is a Russian instrument, its principal investigator is Dr. Igor Mitrofanov, who entered the Launch Support Room only a minute before the pizza arrived, so my conversation with him had to be cut short. He's busily studying telemetry from the instrument at the moment.
Pizza!
One of the Goddard deputy directors has bought pizza for the entire crew! I thoughtfully cleared a space at a table I'm using so they could put the pizza there.
Thus giving me home-field advantage. I fully exploited this.
Thus giving me home-field advantage. I fully exploited this.
Lunar Cruise Day 1
The MCC went extremely well. We'll have the definitive report on how well our course was adjusted within a few hours.
Our next milestone is huge...Lunar Orbit Insertion #1 (LOI-1). This 40-minute burn will take place very early on Tuesday morning (6/23). If we succeed, we'll settle into orbit. If we fail, we'll sail past the Moon into deep space.
In the meantime, we'll be switching a couple of the science instruments on and doing some checkout. I also expect to receive updated calibration parameters for the star trackers and the gyroscopes. Launch vibrations may have affected their positioning slightly with respect to the rest of the spacecraft. We can tell the onboard computer how to compensate for this effect. The uplinked product is very similar in form to what we uplinked for the burn today, but is not a quick-turnaround requirement, so I will create it by building them in the flight software, rather than using our customized generation process employed for the burn products.
Our next milestone is huge...Lunar Orbit Insertion #1 (LOI-1). This 40-minute burn will take place very early on Tuesday morning (6/23). If we succeed, we'll settle into orbit. If we fail, we'll sail past the Moon into deep space.
In the meantime, we'll be switching a couple of the science instruments on and doing some checkout. I also expect to receive updated calibration parameters for the star trackers and the gyroscopes. Launch vibrations may have affected their positioning slightly with respect to the rest of the spacecraft. We can tell the onboard computer how to compensate for this effect. The uplinked product is very similar in form to what we uplinked for the burn today, but is not a quick-turnaround requirement, so I will create it by building them in the flight software, rather than using our customized generation process employed for the burn products.
Lunar Cruise Day 1
Our mid-course correction will occur in about 15 minutes. The burn will be commanded by an onboard command sequence, making the start time very precisely controlled.
Lunar Cruise Day 1
I forgot to mention that when I arrived home this morning (about 8 AM), I saw my name in the latest issue of Skeptical Inquirer magazine, which had just arrived in the mail yesterday.
As president of the National Capital Area Skeptics (ncas.org), I'd had the privilege of presenting an award in front of over 200 people at an international conference held in Bethesda, Maryland back in April. SI coverage of the conference included that event. Here's more information (including video) about that:
Video
Transcript
Award citation
Award
As president of the National Capital Area Skeptics (ncas.org), I'd had the privilege of presenting an award in front of over 200 people at an international conference held in Bethesda, Maryland back in April. SI coverage of the conference included that event. Here's more information (including video) about that:
Video
Transcript
Award citation
Award
Lunar Cruise Day 1
Associated Press article:
http://www.washingtonpost.com/wp-dyn/content/article/2009/06/18/AR2009061800978.html
CNN:
http://www.cnn.com/2009/TECH/06/18/nasa.rocket/index.html
Okay, here's the full launch video (thank you, YouTube!):
http://www.youtube.com/watch?v=j-5t4de6jjI
or try the "high quality" video:
http://www.youtube.com/watch?v=j-5t4de6jjI&fmt=18
http://www.washingtonpost.com/wp-dyn/content/article/2009/06/18/AR2009061800978.html
CNN:
http://www.cnn.com/2009/TECH/06/18/nasa.rocket/index.html
Okay, here's the full launch video (thank you, YouTube!):
http://www.youtube.com/watch?v=j-5t4de6jjI
or try the "high quality" video:
http://www.youtube.com/watch?v=j-5t4de6jjI&fmt=18
Lunar Cruise Day 1
I'm awake, having grabbed a couple of few-hour naps overnight. The first one was a problem due to adrenaline aftereffects. My mind was still racing with memories of the launch, and thinking ahead to pending tasks.
Here's a NASA TV replay of the launch:
http://mfile3.akamai.com/18566/wmv/etouchsyst2.download.akamai.com/18355/wm.nasa-global/ksc/ksc_061809_lrolcross_launch.asx
This is an abridged video that omits some of the coolest parts...it ends before orbit is achieved, and the Atlas cuts off and separates. Then the payload fairing separates and the Centaur upper stage burn begins. Hopefully NASA will post the full video later.
From the LRO blog, it looks like things have continued to go well with the spacecraft.
I got a few hours sleep until about 4:30, then I headed back to Goddard, which is not far from home. Before I left my bedroom I looked out my back window and spotted our target through the trees.
It was easier to see on the drive in, a waning crescent. Below it is the planet Venus.
I got in at 5 AM, just as the data for the mid-course correction (MCC1) were ready for conversion into the onboard computer-readable format. My colleague Mike and I completed that within a few minutes, then I headed over to the primary spacecraft simulator, called "FlatSat" (so named because the satellite simulator components are flat on a table). We test-loaded the products to a duplicate of the onboard computer and observed its response. No issues.
I headed back to the Mission Operations Center and confirmed that the products were verified and ready for uplink to the Orbiter. That probably happened a few hours ago when I was asleep. Tonight at 6:16 PM EDT is when the relatively brief (38-second) burn will take place. The Atlas and Centaur performed so well that we only need to do a bit of a touch-up on our course.
Last night, when I handed off the Flight Software station in the Launch Support Room to my successor, I said, "You have the conn, Mr. Trout." "What is that, Spock-speak?" he said.
"Indeed," I replied.
Thursday, June 18, 2009
Launch Day 8:45 PM
Checkout of the thrusters (by performing test firings) is complete. We've also done our first "wheel unload" (the reaction wheels' angular momentum has to be adjusted using the thrusters). No problems.
We have a mid-course correction (MCC) coming up tomorrow. My role in that is to convert the thruster calibration values and other burn-related parameters into a form that the onboard computer can "understand." I'll also support the testing of that, as well as the uplink to the orbiter (as we call LRO in everyday conversation). I'll be back here in the wee hours of the morning when we expect those input data to arrive.
I worked with one of my colleagues to create a very reliable and fast conversion process for the burn-related data. Tomorrow morning is its first use outside of simulations.
We have a mid-course correction (MCC) coming up tomorrow. My role in that is to convert the thruster calibration values and other burn-related parameters into a form that the onboard computer can "understand." I'll also support the testing of that, as well as the uplink to the orbiter (as we call LRO in everyday conversation). I'll be back here in the wee hours of the morning when we expect those input data to arrive.
I worked with one of my colleagues to create a very reliable and fast conversion process for the burn-related data. Tomorrow morning is its first use outside of simulations.
Launch Day 8 PM
The solar array and high-gain antenna deployed correctly. The star trackers are on. Now LRO can very precisely determine its attitude in space. The spacecraft has left Sun Safe mode and entered Observing mode, which is the everyday attitude-control mode.
LRO is maturing quickly and without incident.
LRO is maturing quickly and without incident.
Launch Day 6:34 PM
LRO has attained sufficient velocity from the Centaur upper stage so we've now (as of 6:17 PM) separated from it. Still attached to the Centaur is the LCROSS "shepherding spacecraft" which will watch as the Centaur impacts the Moon in October, fly through the plume, and itself impact several minutes later.
Still ahead for us is deployment of the LRO solar array and high-gain antenna. Prior to that is something that involves the flight software team...activation of the data storage boards.
Still ahead for us is deployment of the LRO solar array and high-gain antenna. Prior to that is something that involves the flight software team...activation of the data storage boards.
Launch!
LRO and LCROSS lifted off at 5:32 PM...we're on the way to the Moon!
Our video feed of the launch shown in the LSR was delayed by a few seconds, so there was a strange few seconds during which our countdown had passed through zero but the rocket was still on the pad. But the engines lit and it slowly ascended into a cloudy sky.
Our colleagues in Florida ran outside to see the launch once it had cleared the tower, but it had already gone into the clouds by that time.
NASA TV carried the view from the camera on the side of the upper stage, looking Earthward...spectacular view as we cleared the clouds and headed into space. Several minutes later, we saw the Atlas booster separate. The Centaur upper stage fired and then the payload fairing was jettisoned successfully, triggering a round of applause here in the LSR.
The Centaur will fire for about 40 minutes to give us sufficient velocity to reach the Moon.
Our video feed of the launch shown in the LSR was delayed by a few seconds, so there was a strange few seconds during which our countdown had passed through zero but the rocket was still on the pad. But the engines lit and it slowly ascended into a cloudy sky.
Our colleagues in Florida ran outside to see the launch once it had cleared the tower, but it had already gone into the clouds by that time.
NASA TV carried the view from the camera on the side of the upper stage, looking Earthward...spectacular view as we cleared the clouds and headed into space. Several minutes later, we saw the Atlas booster separate. The Centaur upper stage fired and then the payload fairing was jettisoned successfully, triggering a round of applause here in the LSR.
The Centaur will fire for about 40 minutes to give us sufficient velocity to reach the Moon.
Launch Day 5:00 PM
A lightning storm is passing nearby as of 5 PM, too close to allow launch. Launch control has decided to bypass the first two launch windows and shoot for the last window (5:32) of the day. The constraint is that no lightning strikes can occur within a 10-mile radius for the previous 30 minutes. Choosing 5:32 gives us the best chance for liftoff today.
Launch Day 3:45 PM
Try this link for NASA TV coverage:
http://www.nasa.gov/55644main_NASATV_Windows.asx
It looks as if it's running about 45 seconds behind the live feed, but at least it's available.
http://www.nasa.gov/55644main_NASATV_Windows.asx
It looks as if it's running about 45 seconds behind the live feed, but at least it's available.
Launch Day 11:28 AM EDT
The launch forecast shows a 40% chance that weather constraints may be violated by Anvil Clouds, Lightning, or Cumulus Clouds.
A problem has cropped up a few minutes ago. Commands from the Astrotech Space Operations facility (near the launch site) are not getting into the spacecraft.
The LRO weblog has the most up to date information:
http://lroupdate.blogspot.com/
Time magazine has an article about LRO:
http://www.time.com/time/health/article/0,8599,1905344,00.html
Here's a nice shot of SLC-41 with LRO/LCROSS on the Atlas-V, and in the background, shuttle Endeavour on Pad 39-A at nearby Kennedy Space Center:
http://www-pao.ksc.nasa.gov/kscpao/images/large/2009-3750.jpg
New York Times article:
http://www.nytimes.com/2009/06/16/science/space/16moon.html
I don't know how closely NASA TV will show the Flight Software station in the Launch Support Room, but if they do, you'll see four mission patches that I adorned our two monitors with. Apollo 11 and 17 patches represent the first and last manned landings on the Moon, and Constellation and Orion represent the future return of humans to the lunar surface. LRO bridges the past and future of human exploration of the Moon.
Wednesday, June 17, 2009
LRO Ready for Launch
This morning, the Lunar Reconnaissance Orbiter and its launch vehicle, an Atlas V rocket, were rolled out to the launch pad at Cape Canaveral Air Force Station's SLC-41 [Space Launch Complex-41]. Here's a live updating picture:
http://www.floridatoday.com/content/maps/spacecam15.shtml
Surrounding the rocket are four lightning protection towers.
Atop the 200-foot Atlas/Centaur with LRO is LCROSS (Lunar Crater Observation and Sensing Satellite), which will impact the Moon in October. Its objective is to learn if water ice exists in permanently shadowed craters near the Moon's South Pole.
Launch is set for Thursday, June 18 at 5:12 PM EDT, with two other opportunities at 5:22 and 5:32. We'll pick up again the next day at 6:41 PM if we can't go Thursday. The journey to the Moon will take about four days.
NASA TV coverage begins at 2 PM EDT, carried in high-definition, and on the web at
http://www.nasa.gov/ntv
Two LRO mission operations rooms at Goddard Space Flight Center will be part of the live coverage: the Mission Operations Center (MOC), and the nearby Launch Support Room (LSR). (I will be at the FSW (Flight Software) station in the LSR.)
As soon as the rocket clears the pad, the MOC will have control and responsibility for the spacecraft.
Four days later will be our next major milestone: LOI (Lunar Orbit Insertion). A long burn of our engines will be required to establish a lunar orbit. Otherwise we will fly past the Moon into deep space. There are still contingencies available to swing back and try again, but they will burn off too much of our fuel to fully complete the mission.
Subscribe to:
Posts (Atom)