MRO MOI Events Timeline, Time Zone Friendly Options

[djellison]

Z = GMT / UT, P = Pacific
Future, Unconfirmed, Confirmed

NASA TV coverage starts at 2030Z / 1230P

TCM5 was not required.
2049Z / 1249P - Tank Pressurize - nominal pressure reported (@2053Z)
2103Z / 1303P - Switch to LGA ( 2 way doppler @ 2104Z, Lock at 160bps :2105Z)
2107Z / 1307P - Turn to Burn attitude (start of turn confirmed via doppler & telem @2110Z - Slew finished @2119Z via ACS)
2124Z / 1324P - Start of MOI Burn (confirmed via Doppler @2123Z )
(tank pressure about 3psi below predicts but within margins @2131Z )
(307m/sec accumulated delta @2135Z)
(401m/sec accumulated delta @2139Z)
(588m/sec accumualted delta @2144Z)
(telem. indicated eclipse entry @2146Z)
2146Z / 1346P - Loss of signal ( confirmed on doppler @2147Z- actual time 21:46:23Z)
2151Z / 1351P - Nominal End of Burn
2216Z / 1416P - Nominal AOS - (signal aquired - 1 way doppler @2116Z - 22:16:08 actual time)
(2 way doppler @2223Z)
2230Z / 1430p - 1641m/s burn indicated by telementry.

MRO is now orbiting the planet Mars

Status check at 2245Z
Flight Software - Burn done at 20% Utilisation
Prop Nominal
ACS, Earth point on reaction wheels, Star tracker aquisition ( 8 stars ), Burn time 1641 seconds vs 1606 expected. 1000.48 m/s compared to 1000.36m/s expected.
Thermal - all temps nominal. A few alarms due to soak back from the rcs thrusters.
EPS - Nomincal, trickle charging batts ( 110% state of charge ) - 870 Watts being used, 1650 Watts available from arrays.
Telecom - Nominal, on primary equipment, uplink and downlink signals as expected, already got a command in.
Fault Prot - Quicklook, no abnormal responses to the burn, out of go-fast mode.
Nominal termination to the MOI nominal block.






http://mars.jpl.nasa.gov/mro/realtime/mro-doppler_lg.html
Interesting Pre MOI PDF Presentation
http://www.hq.nasa.gov/office/codeq/smadir/hq06/landano.pdf



11th March 0030 Press Conf Update

Usual superlatives from senior management that don't tell us anything.

Jim Graff acknowledged help from NOAA w.r.t. Solar Weather, and the DSN's outstanding job.
Howard Eisan : MRO is safe, stable, on earth point, transmitting at 550kbps. We've earned the 'RO' of MRO. Dippled less than 10% into the batteries, commanded velocity change 2237.6 mph, overshot by 0.4mph, during the burn we underperformed by 2%, burned by 33 seconds longer to make up the difference. First hr of Nav data - orbit 35.5 hrs (predict 35.6) 264 x 28,000 mile orbit.
Rich Zurek : 2 of our 8 investigations were ones lost with MCO, one of those was also lost with Mars Observer. This completes replacement of all the Mars Observer instrumentation. We're going to knock your socks off - it's a good day.

Sally from TPS : Break for 2 weeks, what are you going to be doing (are you going to be celebrating for two weeks) - JG - stand down for w'end for a rest. Then prepare for aerobraking. ORT for Aerobraking, reconfig spacecraft for aerobraking, and some software patches to send up (9 uploaded to date, a few more to go). One other thing - we will take some early images - engineering images not science quality, make sure they work properly, processing that data on the ground to make sure the processing centres can extract the images from the data.

Sally asked when that science will start. RZ mentioned the use of aerobraking (lowest altitude is 60 miles) to understand structure of atmosphere. Sally asked if aerobraking is hard every orbit. RZ said that most of the closest approaches will be over the south pole. They dont expect big dust storms.

That's all the questions- again, kudos to Sally for asking them something. Unarguably the most important moment in Mars exploration since MER landing and potentially more important than anything between then and MSL landing scientifically, and in terms of infrastructure on orbit - $700M's worth of project - and that's three conferences where Sally was almost the only person to ask any questions. Either JPL PAO has furning the media with every single piece of information they could want before the event, or the media seem to be barely taking note of the mission because it's not as sexy as a landing ( there were plenty of spare seats in the V.K. auditorium, at Spirit's landing conf, you couldnt swing a cat in there ). Under-representation of mission rant over.

Doug

Attached File(s)

 doppler_1.mov ( 119.34K ) Number of downloads: 382

 

[Bob Shaw]

More and more spacecraft will hopefully make it to Mars in the near future....it might be prudent now to start on a more extensive COLA/tracking/space debris reduction program before it becomes an issue. Same with the Moon.

Lunar orbits tend to be quite unstable, especially low ones, so there's almost certainly nothing other than SMART-1 in Lunar orbit at present - we're a long way from needing traffic cops there!

Bob Shaw

[Guest_BruceMoomaw_*]

An odd note from the March 6 Aviation Week: The pre-MOI repressurization of the hydrazine tank "caused a little anxiety because Mars Observer was lost at the same point in 1993, believed due to overpressurized tanks from a faulty orifice in the pressure regulator sensing line."

This is a totally different theory for Mars Observer's loss from the one I've always seen listed as most probable: nitrogen tetroxide oxidizer leaking past a check valve into the hydrazine lines and setting off an explosion in the latter when the hydrazine first came down them. Is AW mistaken and the pressure-regulator theory is just one of the less likely alternate possible causes listed in the MO failure report, or has there been some recent rethinking on the most probable cause of the accident?

[edstrick]

I was looking at that report and wondering the exact same thing....

I suspect a lot of the engineers and reporters have never read or essentially forgotten the full range of plausible failure modes ... I sure have forgotten all but the "somewhat most plausible" one.... and the reporter may be quoting one engineer or manager's take on the MO failure who's also working from memory.

[Jim from NSF.com]

Maybe this was the only plausible failure mode applicable to MRO

[edstrick]

Engineers and mission controllers on these missions have incredible regenerative abilities .... they routinely chew their fingernails back to their armpits during the runup to these mission critical events.

[mcaplinger]

Is AW mistaken and the pressure-regulator theory is just one of the less likely alternate possible causes listed in the MO failure report, or has there been some recent rethinking on the most probable cause of the accident?

The latter. From "Propulsion Lessons Learned from the Loss of Mars Observer", Carl S.Guernsey, JPL, 2001:
"This paper presents an overview of the potential failure modes identified by the JPL review board and presents evidence, discovered after the failure reviews were complete, that the loss was very likely due to the use of an incompatible braze material in the flow restriction orifice of the pressure regulator."

Complete paper is online at
http://www.klabs.org/richcontent/Reports/F...y_a01-34322.pdf

[Guest_BruceMoomaw_*]

Ah! This is a big item that's totally new to me. Thanks.

[tuvas]

An odd note from the March 6 Aviation Week: The pre-MOI repressurization of the hydrazine tank "caused a little anxiety because Mars Observer was lost at the same point in 1993, believed due to overpressurized tanks from a faulty orifice in the pressure regulator sensing line."

This is a totally different theory for Mars Observer's loss from the one I've always seen listed as most probable: nitrogen tetroxide oxidizer leaking past a check valve into the hydrazine lines and setting off an explosion in the latter when the hydrazine first came down them. Is AW mistaken and the pressure-regulator theory is just one of the less likely alternate possible causes listed in the MO failure report, or has there been some recent rethinking on the most probable cause of the accident?

If I remember right, the pressurization was such a big deal because there was a fairly last-minute change in the code, as I recall, it was set up so there wasn't a redundancy previous to a reprogramming only a few weeks before MOI. I attended a MOI party at the University of Arizona with the HiRISE team (This was right before I joined, my hiring was contitional upon the safe MOI of MRO, imagine that!), and I think that was the story that I heard at the UA MOI party... But, it's been quite a while... Also, please note that I wasn't a HiRISE team member at this point in time, so I don't know if that's really the reason. If that was the reason, then it just goes to show that NASA isn't taking any more chances with it's spacecraft, they are constantly checking things to make them better. MRO has performed almost flawlessly, even with it's more complex than normal instruments.