I have been wondering about something....given the performance of the MERs, if one or both survive this winter, is it not conceivable that they could be operational when Phoenix lands? It would, I believe, be the first landing on anything but the moon with other landers (other than parts of the same mission) still operational.

Um, Viking?

Well ok, they are the same mission. It would speak a lot about the longevity of MERs.

I think there's some potential for functional, if not 'mobile' Rovers come '07. I certianly think they'll last thru to MRO's science orbit, and as such could do simultanious observations out and into the atmosphere.

But that's a long way away, and a hell of a lot could go wrong between then and now, I wouldnt put money on it, but I wouldnt be suprised.

Doug

If we are going to go the same mission route, Opportunity would be from the same mission as Spirit as well. But I was thinking about not-twin missions.

Well, you know, we're within two months of having four working and scientifically productive (and non-redundant) Mars orbiters simultaneously. I think that's quite impressive enough.

This raised an interesting question: What's the success rate of twin missions vs one-shot?

Viking 1/2
Pioneer 10/11
Voyager 1/2
MER A/B
Mariner 1/2 (1 was destroyed during liftoff, so doesn't count)
Mariner 3/4/5 (3 was a shroud failure, so doesn't count)
Mariner 6/7

It's an interesting comparison, anyways.

Don't forget that Mariner 8/9 fit the same pattern, as Mariner 8 was a launch failure.

If still alive, I wonder if one of the rovers could see the entry fireball of Phoenix. It would be a great way of calibrating the images of possible meteors seen by the MERs.

I doubt it - Phoenix's landing site is going to be a long long way from the rovers. It'd be like trying to see the Stardust re-entry from Cuba.

Doug

Yep - if we assume that the potentially visible entry stage begins at around 120km altitude it will only be visible within a zone that spans at most +-15deg from the re-entry track. Since Phoenix is going to land at ~70deg N any martian surface observer would have to be norrth of around 55deg to have any chance of seing it.

I think that even if you adjust for obliquity and the fact that it's approaching mid summer at landing time the lowest latitude you could possible see anything from would be ~32 deg N in the very unlikely event that the initial atmospheric entry happens at local midnight. I might be wrong in my assumptions on this one but I suspect that if even if I am the reality would be even less favourable.

Remember - Mars is much smaller than earth, so the horizon is much closer as well, if the exact path of Stardust were replicated on Earth, those lines showing visibility at specific elevations would be much much closer to the entry track

Doug

Doug - I based those numbers on calculating horizon distances with a Martian radius (3397km), 1deg ~ 59km.

The 120km altitude is just a pure guess - I'm assuming that "entry" starts somewhere around there but I don't know for sure where it would actually happen.

Can't remember off hand, but on the EDL live coverage, Wayne Lee mentions that atmospheric entry occured fairly high, but deceleration didnt occur for about another minute or so, and I'd only expect to be able to see a plasma trail etc after deceleration starts to occur. perhaps 75km?

Looking at this
http://atmos.nmsu.edu/PDS/data/mpam_0001/edl_ddr/edl_ddr.tab
and this
http://atmos.nmsu.edu/PDS/data/mpam_0001/e...dr/r_eacc_s.tab

The peak decel was at 30 - 40km

Doug

In this connection, Pioneer 12's imaging photopolarimeter was actually used to try and photograph the firing of Magellan's orbital insertion motor, but saw nothing. A pity.

IIRC, wasn't there also an effort by HST to image the Galileo Probe entry? I also remember (dimly) some talk about doing the same thing for the orbital insertion burns of MGS and/or MCO.

Since there might be up to four functioning orbiters around Mars when Phoenix lands it seems that there would be a good chance that one or more of them might have the landing site in view. A plasma trail should be fairly easy to see particularly at night. The location should be known within a few tens of kilometers and the time to within a second or two.

tty

It will be very difficult to see at night, mostly because Phoenix will be landing in the afternoon . But there should be better than a good chance an orbiter will have line of sight to Phoenix during EDL, since that is a requirement. However, I don't know whether imaging is consistent with the required UHF listening (that may depend on which orbiter).

I hope Phoenix lands in the daytime; I could quit working on MARDI/PHX if it doesn't.

We tried imaging the entries of both MERs using the MOC WA, and didn't see anything definitive.

Mars Phoenix Lander will land during daylight, late afternoon.

The potential landing sites are all north of the Martian Arctic Circle.

Mid Summer Solstice on Mars will be on 24th June 2008, just three days after that on Earth (a strange co-incidence).

Mars Phoenix Lander hopefully will take time lapse images of the Martian Midnight Sun!!!

Andrew Brown.

Well, since this thread got resurrected however briefly, thought it might be fun to see Doug's prophetic words from a year and a half ago...let the good times roll!!!

regarding imaging of Phoenix's entry... Most cameras in orbit at mars are not framing type imaging sensors. The experimental navigation cam on MRO is, and the little engineering cam on Mars Express that imaged Beagle as it separated, but that's about it.

Doesn't stop you doing a nodding-spacecraft manouver to try and grab one with a push broom (i.e. MOC WA for MER etc) - I wonder if CTX could have a go this time around...spacecraft geometry is probably the limiting factor.

Doug

Emily confirms that there's a microphone attached with Mardi. I wonder if it can be used once on the ground even if Mardi itself will be of no use?

BTW, the landing day, May 25th 2008 is NOT a Mardi, it's a Dimanche instead

There's a picture of the microphone at http://www.msss.com/phoenix/mardi/index.html so I don't think it was a big secret.

MARDI can take perfectly good images of the surface from the height of the landing legs (and I think this might even be an area that the SSI and RAC can't see) and the microphone would work post-landing, but there are no plans to operate MARDI then. Recall that the PHX mission has a limited duration and the other instruments use up most if not all of its lifetime.

Would this return any interesting data in terms of the exhaust pattern from the engines? IIRC there was some question about the extent the soil disturbance from landing...

And nice picture!*


*Swiss Army Knife not included.

Nope, it certainly wasn't a secret; in fact most of my information came from the mission press kit, which was posted on Monday.

Cool that MARDI could be used to take a photo of what's under the lander! I'm not sure what value that would have -- but it would be cool.

--Emily

No, but the apparent engineering collaboration between MSSS and the Swiss Army is certainly news.

Well, it might make polar-projected images of the landing site a bit more complete - no more black hole right in the middle!

Thanks for the answers all, but my question was about the use of the microphone once on the ground. Any infos ?

I answered that: it would work but there are no plans to operate MARDI post-landing.

Got the point this time Mike! I thought image & sound could have been kind of independant. Thanks

From today's ESA release, sounds great to me...:

"Operations experts at ESA are currently studying ways to use Mars Express to communicate with the Phoenix lander during its 90-day mission. This could increase the amount of scientific data returned by the lander, as Mars Express would have the capacity to contact and command the lander every two or three days, as well as serve as a relay station for commands and back-up in case of NASA spacecraft failures. Mars Express could also record data if Phoenix goes in safe mode."

About time We should have been doing UHF relay for MER as a 'payback' for borrowing the DSN so much

Doug

What do you mean by "borrowing"? You mean for free? I didn't realize ESA didn't pay (or barter) for time on the DSN.

Here's a gift for the weekend for all of you detail-fans...

Click to view attachment
Looks like the stage is ready...

Freakin' awesome...thanks, Rui!

Man...the level of detail, the simulations, the constant discovery of disconnects & bugs...it is always so impressive to see the dedication and foresight of these people who dare to send robots to explore the planets!!!

You're welcome nprev...

Did you see the size of the trench?! That baby will REALLY dig!!

Ohh, yeah...more power, more power!!! (grunt, grunt) Hopefully we'll see the glimmer of ice down there...

As I understand, during landing site selection, there was a concern of
seeing too much ice and not enough soil to do mineralogy/chemistry on.
Seeing ice should be a given, but I guess planners have been surprised
before with respect to actual vs. predicted landing site conditions. As
always it will be exciting waitng for those first images of the landing site,
and then the first -- and subsequent -- images from inside the trench.

Stu, our intrepid reporter got some goodies from Mark Lemmon among which are how things will develop on landing day and what we can expect in the first days regarding images...

I'm always amazed and grateful when these guys take the time to reply to emails, especially when they answer so fully. There are some really interesting news bits in there, made me even more excited about Phoenix...

An absolutely terrific article, Stu; outstanding work!!!

A must-read for Marsophiles--now I know exactly what to expect on Landing Day.

Glad you enjoyed it, I was v v v chuffed that Mark was so forthcoming. I can start planning that weekend now! Thankfully, the Phoenix landing coincides with my weekend off work, so I can camp by my computer and follow the whole thing as it happens... if I've got my time conversions right then Phoenix should land at around 11pm on the 25th my time, the first picture should be released within an hour, taking me to midnight, and any JPL Press Conference, with pictures to show, should be about 5am Sunday morning BST (Bleary-eyed Stu Time )

Good to hear that there'll be a raw images site, and great to hear that they'll - hopefully - be accepting image contributions from people "out here"...

I am getting quite fidgety now to see what Phoenix's surroundings will be after landing, aren't you..?

Why do these guys always plan this events to hours where one must be dreaming of Mars?...
Dear Stu, your work was truly helpful on letting us all know how things will run within...less than 9 weeks now?...Already?!

Well -- someone correct me if I'm wrong, but 11pm in the UK is 7pm in New York, 6pm in Minneapolis (my locale), and most important, 4pm in Pasadena. So the guys in charge of EDL get to work it in the middle of the afternoon, their time.

Of course, the first pictures will come down "after hours" for any American location. But not so late as to be interrupting anyone's beauty sleep...

Besides, if you want to land at a given place, with a given sun angle, after a launch on a given day, you don't have many choices in terms of planning. The landing will happen at a specific time, and it's moot whether or not that's a convenient time for the engineers, scientists, or even us fascinated spectators... (Talk to me sometime about the times in my early and mid teens I would sit up all night watching lunar landings and moonwalks. Apollo 14 happened in a dark world in my memory, because most all of the lunar activities happened when it was dark in the central U.S.)

-the other Doug

Doug, you took my expression too literally...I was referring more to that 5am press conference, which by the way Stu...isn't it on Monday morning, working day already?...

Don't tell me I'm the only one that plans vacation days
from work around significant space exploration events.

Great interview by Stu on your blog, ustrax. I think I'll
let the folks over at the space.com Phoenix thread know about it.

I think I'll arrive the office sooner than usual...
If it were a month earlier it would be the perfect long weekend...

Yes, Stu made a splendid job! ustrax just loves his crewmates...

And don't forget to participate in the competition!

I'm probably going to take the Monday off, I wouldn't get any work done even if I did go in.

It's the Spring Bank Holiday Monday James WIN

Doug