Thanks Redstone - that is indeed impressive.

Mars 2 was so close it did not need a final correction. There was not a contingency in the software for a burn of zero deration, and this is thought to have goofed up some of the bookkeeping & timing, screwing up the mission. I notice that on Cassini, when they cancel a burn, they quite often send modified code to replace what would have happened as part of the burn sequence.

I don't know if the real historical record is different from what was the "official" history 20 years+ ago, but supposedly Mars 2 had an attitude contol system failure and once it was in orbit, they had to spin-stabilize it in a slow rotation to keep it alive and all it returned of value was fields-and-particles data, and I don't think hardly anything was published from that, in comparision with Mars-3 orbiter data.

Mars Reconnaissance Orbiter was only 1000000 kilometers away from Mars at 2006-03-06 21:22:47 UTC.

Mars Reconnaissance Orbiter was only 500000 kilometers away from Mars at 2006-03-08 22:14:28 UTC.

The velocity relative to Mars was 2.852 km/s. (13.9x slower than New Horizons relative to Pluto)

here's an article from one of our local papers:

http://www.tucsoncitizen.com/news/local/030806a1_mars

Apparently, a version of the article posted earlier today described a Mars Renaissance Orbiter. Now a number of folks in the HiRise Operations Center (really just a tucked away hallway in our building) are dressed up in renaissance costumes...

Good grief, only a few more days until this madness ends.

Jason:

What better time to test the management's Equal Opportunities Policy than at a mission-critical moment?

Ah, the roar of the grease-paint! The smell of the crowd!

Men in what look like rather fetching little frocks...

Bob Shaw

Jason, that's something that just demands taking a photo that you can torture them with later

--Emily

If only I could find the memory card for my camera, it would be a good photo op. Unfortunately, no one went for the gold here. Mostly just people in Robin Hood caps...

This is the approx. timeline of MOI events:

10:24 a.m.: Final trajectory correction maneuver if needed
04:07 p.m.: Start spacecraft turn to orbit-insertion orientation
04:19 p.m.: Turn complete
04:24 p.m.: Orbit insertion rocket firing begins
04:45 p.m.: Spacecraft enters Martian shadow; on battery power
04:47 p.m.: Loss of signal as MRO passes behind Mars
04:51 p.m.: End of orbit insertion burn
05:13 p.m.: Spacecraft turns for Earth pointing
05:16 p.m.: Acquisition of signal

There was some discussion here before about the suspense until AOS and the two possible times --actually a range-- for that event, the earlier the worst.

My question is if there is really that "suspense" given that 23 of 27min of the firing will be made with MRO on sight i.e. with telemetry data? Off course, there are a lot of bad things that may happen on those later 4 minutes (or even later), but what would happen if the burn is cut short at exactly 23min? Would that be enough to enter orbit -- surely a very excentric one -- and would it be recoverable? If the answer is "yes" the suspense is really not that much, if the answer is "no" (knock on wood) there is actually no suspense, it's a bad day.

Well - using Orbiter with a 400km MOI burn aim point - and this is all very rough

The trajectory switched from a flyby to an actual orbit after 26 mintues of Burn - so the bit of burn after LOS, is arguably the most critical

I think the time for reaquisition should be the big marker - I know they say it'll take half an hour of tracking to get a prelim. orbit for the spacecraft, but I'd have thought the actual time of reaquisition would probably be the giveaway as well.

Doug

So a 26 minute engine burn is the minimum needed to enter into any kind of orbit? I remember them saying something simiilar during Cassini's arrival - about 73 minutes into the 96 minute engine burn

I'm not sure of the exact figure - but the post MOI orbit is already very elliptical - I can imagine that it would only have to be a a little shy of the required Delta V to not make an orbit at all

Doug

The nominal burn is 26.8 minutes, of which 21.5 minutes are in view.

The minimum delta-V for capture is reached about 2 minutes after LOS.

Mars Reconnaissance Orbiter was only 200000 kilometers away from Mars at 2006-03-10 03:18:30 UTC.

range-rate = -2.895 km/s
velocity = 2.897 km/s