Dec 4th News Conference Options

[Guest_Bobby_*]

Oppy & Spirit will still be Trucking Along in 2012

[sci44]

Oppy & Spirit will still be Trucking Along in 2012

By that time Oppy will probably be excavating that Fossil bed on the far side of Endeavour.. :-)
This graphic illustrates why having MRO around at that time will be useful (I know its total data return, not bps, but still..) It will be interesting to find out how much more data might come back from MSL compared to the MERs..

[nprev]

Hmm. You know, if (a big if indeed, I know) the MERs are still doing their thing in 2012, can we in a worst-case scenario of being down to one relay orbiter still get max data return from three rovers?

The MERs are on opposite hemispheres, of course, but MSL's gonna be somewhere in between them. The surviving orbiter's transceiver would have to work pretty hard; does it have a duty cycle? Might be difficult to select an optimal orbital plane to maximize coverage as well.

Just curious to know if any modeling of such a contingency situation has been done.

[mcaplinger]

Can we in a worst-case scenario of being down to one relay orbiter still get max data return from three rovers?... Might be difficult to select an optimal orbital plane to maximize coverage as well.

Changing planes is expensive in delta-v and unlikely to be done unless needed to cover the MSL EDL.

Having three rovers to service given the relatively low UHF rates that MER can use shouldn't really be very stressing if MRO is the relay. The return from two MERs is lost in the noise of what we expect to get from MSL. If Odyssey were the relay, it would be more constrained, and you might see the MERs using more DTE than they do now, depending on their condition in this scenario.

[elakdawalla]

As much as I love and admire the MERs, I think having three rovers and one orbiter in 2012 is a much less likely scenario than having three orbiters and one rover.

--Emily

[nprev]

True, Emily. Playing "what-if" is a very popular & actually addictive game in space systems engineering, though...

Mike, thanks for the answer. I assume then that the limiting factor is the orbiter-Earth link bitrate, not the rover-orbiter link?

[Tesheiner]

Does the two Year delay change the time of Year at which MSL would land at Southern Hemisphere landing sites?

I ask the question because I understand that if MSL had landed in 2010 at the Southern Hemisphere Eberswalde and Holden crater sites then the landing would have been in the depths of Winter and MSL might have been virtually immovable for the 6 months following the landing.
<snip>

Don't forget that MSL is nuclear powered so seasons are not a constraint for power generation.

[monitorlizard]

If I'm interpreting Ed Weiler correctly, NASA and ESA working jointly on a 2016 ExoMars rover would not only greatly help ESA's funding problems, but would save NASA a tremendous amount of money in not sending its own Mars rover in 2016. That could really help NASA pay back money it will "borrow" from the Mars program to pay for the MSL delay.

A little aside: I'm delighted that there will now be two extra years of MRO (especially HiRISE) returning maximum science data from Mars. I didn't want it to happen this way, but you might as well be an opportunist about such things.

[mps]

Can anybody here think of what planetary missions there are that would have big budgets in 2010 and 2011 for MSL to raid? The only one I can think of is Juno.

Assuming there will be no more delays (which isn't very realistic), there will be four (sic!) planetary missions launched in 2011: LADEE, Juno, GRAIL and MSL
I'm afraid that NASA will find tempting to cancel the first one in the list - although it has a small budget (ca $100M), it's still in early phase and isn't such a sexy mission for public's eye.

[PaulM]

Don't forget that MSL is nuclear powered so seasons are not a constraint for power generation.

Have a look at the posts by Tim and Emily on the following page:

http://www.unmannedspaceflight.com/index.p...=4565&st=15

Tim's post contained the following paragraph:

"Holden and Terby came very close to not making the final list. They are both very interesting scientifically, but we were told by the engineers that because of their high southern latitudes and cold temperatures that if MSL landed at one of those sites it would have to lie dormant for the first month or so and then operate at only a 30-50% duty cycle. There was a lot of debate about whether the science that could be done at those sites outweighs those limitations. In the end it was a close vote, but both were kept on the final list."

There seemed to be real concerns a Year ago that if the Holden Crater landing site was selected then for the first month or so most of MSL's power generation would have to be used to power survival heaters.

My question is whether the Season in the Southern Hemisphere will be any different at the new MSL landing date?

[elakdawalla]

It's a good question but I don't know what the landing date would be. Hazarding a guess that it'd be midsummer 2012, you're looking at Ls around 130, which is midwinter in the southern hemisphere. That's bad for power (because MSL would have to use lots of power just to warm up motors before moving), but depending on how you look at things it might not be as bad as it would be for a 2009 launch, where it'd arrive in early winter. The 2010 landing might have better temperature conditions on the day of landing, but there'd be a long period of things not getting better after landing. The 2012 landing might have about the worst temperature conditions of the year on the day of landing, which should be steadily improving with time, so there would be a shorter period of relative inactivity following landing.

--Emily

[Doc]

3 of the landing sites currently being considered are in the southern hemisphere (Mawrth is in the north).
However should they decide to take Gale it would spare them the brunt of the southern winter when they land during the assumed Ls 130 (at -4.49 degrees)

[brellis]

Alan Stern had something to say about this today: Article

[peter59]

I would like notice that the postponement Mars Science Laboratory mission and the consequent increase costs may cause the termination of the mission Opportunity and Spirit. The consequences of this delay will be unpredictable, and Spirit and Oppy may be their first victims. I expect that shortly will begin dispute in NASA about this topic. The future does not look too good in my oppinion.
PS.
I know that I can be banned by Doug due spreading defeatism. But that's not defeatism, we must be realistic. I think that this option we should also take into account.

[dvandorn]

At the risk of continuing this divergence in the thread, I'll point out that extended mission ops are the cheapest portion of a planetary mission. The biggest costs are for the DSN time to get the data back to Earth. The remaining costs are mostly for the manpower -- the salaries and benefits of the teams working the missions. And in the case of the MERs, many of those are only working part-time on Oppy and Spirit, spending much of their time on MSL and other projects, as well. (Amortized costs of things like the computers used by the MER teams, the office space they take up, etc., are really pretty irrelevant, after all; it's not like they buy new equipment and rent new facilities for each mission extension. Those capital investments have long since been paid for and depreciated in the bookkeeping.)

Extended ops are the biggest "bang for the buck" you can get out of these things, and NASA has been pretty good about avoiding the penny-wise, pound-foolish approach of cutting $10 million from extended ops to try and make up a $400 million shortfall elsewhere. They're more likely to delay or cancel whole programs before they start racking up their major design and construction costs than they are to cut off assets already in place.

That said, there may be pressure to cut back on Spirit operations if she continues to be power-starved and barely mobile. I don't foresee a project shutdown for Spirit, but you have to admit, we're not getting a huge amount of science data from her recently. Then again, we're not spending nearly as much time (and therefore money) on her as we are on Oppy, either.

-the other Doug