Author Topic: Opportunity rover updates and discussion  (Read 52148 times)

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #100 on: 09/02/2018 08:36 PM »
So, it seems logical that another one would be perhaps solidifying in some form around next year.
I guess we'll see then how the 2020 rover sample earth return features in that, and indeed Mars comms.
It will also be very interesting in other aspects.

No, it won't really get underway until 2020. Astro is going on next year.

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #101 on: 09/02/2018 08:36 PM »
You said daffodils the last time... ;D

Sometimes even strawberries.

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #102 on: 09/02/2018 08:43 PM »
1-There are always choices.  NASA has followed the Decadal Survey which said last time that what became the Curiosity rover was the highest Mars priority and this time sample return (Mars 2020 rover plus advanced planning for actually getting those sample tubes back to Earth)

2-The next Decadal could prioritize a new Mars orbiter.  If it follows the SAG recommendations, it would be a joint science and communications orbiter.  Some set of science likely would fit in a New Frontiers budget.

1-Well, it was a lot more complicated than that. The 2001 decadal prioritized Europa, and that didn't exactly work out. And what became Curiosity is different than what was in the decadal survey, which was a rather vaguely-formed recommendation for a mid-size rover that did some stuff. I think that Curiosity is a great mission and the right mission, but how it went from the decadal to actual implementation is convoluted.

2-A Mars orbiter is likely to be a strategically directed mission and could even be done without a decadal survey recommendation. The Mars Exploration Program (MEP) is distinct, and includes infrastructure requirements. NASA will be creating a new strategic plan for the MEP.

What the DS will likely recommend is that NASA place a high priority on achieving relay capability, rather than recommending a specific mission to do it. That would be separate from any list of prioritized large strategic (flagship) missions or any list of New Frontiers targets.

What MEPAG has been discussing, and is in the new midterm report, is that there will be other science to do on the Martian surface beyond sample return. Assume that sample return happens and brings its own dedicated comms. You are still going to have assets on the surface that you'll want to use to continue doing science, and that's going to require data relay. If Opportunity returns from the dead that will prove that it is immortal and will last forever, so that will need comms. And Curiosity has a lot of life in it. And Mars 2020 will continue roving even after the samples come back. So you don't want to just leave them there.

Offline jbenton

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Re: Opportunity rover updates and discussion
« Reply #103 on: 09/02/2018 09:52 PM »
I have another question about DSN, all this relay stuff, and rovers:

Spirit and Opportunity are/were solar powered, whereas Curiosity and Mars 2020 have RTGs. Oppy is having problems because the Sun's rays can't penetrate the dust cover. The radio waves themselves, to my knowledge are great at penetrating clouds, haze, and dust.

So my question is, does Curiosity have any problems have any problems communicating with the orbiters or DSN during these great global blackouts?

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #104 on: 09/02/2018 10:55 PM »
I have another question about DSN, all this relay stuff, and rovers:

Spirit and Opportunity are/were solar powered, whereas Curiosity and Mars 2020 have RTGs. Oppy is having problems because the Sun's rays can't penetrate the dust cover. The radio waves themselves, to my knowledge are great at penetrating clouds, haze, and dust.

So my question is, does Curiosity have any problems have any problems communicating with the orbiters or DSN during these great global blackouts?

I dunno about "any" problems. But you can find Curiosity images sent during the dust storm. It works.

Here is a dust storm selfie:
« Last Edit: 09/04/2018 02:49 PM by Blackstar »

Offline TripleSeven

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Re: Opportunity rover updates and discussion
« Reply #105 on: 09/02/2018 11:16 PM »
I have another question about DSN, all this relay stuff, and rovers:

Spirit and Opportunity are/were solar powered, whereas Curiosity and Mars 2020 have RTGs. Oppy is having problems because the Sun's rays can't penetrate the dust cover. The radio waves themselves, to my knowledge are great at penetrating clouds, haze, and dust.

So my question is, does Curiosity have any problems have any problems communicating with the orbiters or DSN during these great global blackouts?

The only problem is power to run the transcievers...if the solar arrays dont make power than the transmitter in particular is one of the "greediest" users of power so they try and conserve power by not using it.  The RF system if powered would work fine in the dust.

Offline TripleSeven

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Re: Opportunity rover updates and discussion
« Reply #106 on: 09/02/2018 11:22 PM »
DSN can point to Mars and listen for an hour or more.  MRO (etc.) move fast, can only listen very briefly and have to be at the right place at the right time.

This would be an example why a proper comsat in higher orbit is needed.  MRO and the craft in low orbit can be useful but limited.

If NASA were serious about Mars exploration two such "Relay sats" would already be in operation.  But they are not.

"serious about Mars exploration"

Count the number of spacecraft operating in orbit or on the surface of Mars (and include Opportunity in that count). How many of them are NASA?

So I think that we can agree that NASA is serious about Mars exploration. Now as to the issue of sufficient in-orbit relay capability at Mars, you might look at the recent National Academies decadal midterm report, which has an entire chapter about Mars and was led by a person whom I'm told is tall and handsome and smells of blueberries.

Its not on the tip of my recent experiences but I have read it and other "reports"

As I recall, in brief summary the concern was that as the current relay fleet ages that there wont be sufficient relay capability for a sample return mission, but they are hopeful that since MAVEN and other vehicles are ending their primary mission that they can stretch the fleet...and while a dedicated mars relay would be very useful...the scientist have 1) other priorities and or 2) dont want to pay for it out of their science bucket of money or 3) hope that other vehicles can be used for that but of course the relay "parts" take science payload which they are unwilling or unhappy to part with

Thats what I recall anyway.  I hope the rover comes back, it makes a great RF target and calibration device :)   )  now that the Chinese have their tracking station operating in Brazil...well their lunar relay is a good target.

Glad the guy is tall and handsome...that is important. The smell well maybe as well :)
« Last Edit: 09/02/2018 11:28 PM by TripleSeven »

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #107 on: 09/02/2018 11:47 PM »
As I recall, in brief summary the concern was that as the current relay fleet ages that there wont be sufficient relay capability for a sample return mission, but they are hopeful that since MAVEN and other vehicles are ending their primary

Sample return will carry its own relay capabilities, and they will come back with the sample return spacecraft.

The issue is relay beyond that mission, or if that mission does not happen.

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #108 on: 09/02/2018 11:57 PM »
1-NASA Planetary Science is as "serious" about Mars as it can afford to be while also being serious about the rest of the Solar System. Some, pinning for a new Venus mission - for example, would say too much so.

2-The fact that there are 3 operating orbiters and 1 or 2 operating rovers shows this. What shows this even more is that we know more about Mars than we do about our own oceans!

I'm breaking this post into separate replies and numbering them. Because: reasons.

1-There's actually a real story here, and probably the best place to find it spelled out is in a paper done last year by Jason Callahan and Casey Dreier. But the short version is:

-between the mid-1990s and 2010, NASA spent a LOT of money on Mars exploration. In fact, they could have spent even more, but Dan Goldin actually turned down the money. (I was told this by a senior NASA official who was there. I need to contact him and get that account in writing.)

-when the Obama administration came in they faced several things. They didn't really want to give NASA much more money. They had to deal with the Curiosity and more importantly the JWST cost overruns. They wanted to prioritize Earth science. They didn't care that much about planetary science. And they felt that Mars had received a lot of attention and funding over the years and it was now somebody else's turn. The result was a substantial cut in the Planetary Science Division's budget, and in particular a cut in the Mars Exploration Program budget. As a result, the number of Mars missions has been on the decrease.

-there's some more to this story than that, but the above is sufficient for now.

2-We don't know more about Mars than our own oceans. Right now there are research submersibles exploring our oceans, there are dozens of military submarines under our oceans, taking some data, there are research vessels above and sensors below our oceans, and there are satellites orbiting overhead taking data on the oceans. We know a lot about our oceans. It's just that they are really complex things to study.

Online Blackstar

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Re: Opportunity rover updates and discussion
« Reply #109 on: 09/03/2018 12:09 AM »
3-The problem is that all comms orbiters must have a science mission as well (so far). It's the most cost-effective, most affordable way to do all that the Mars Program wants to do.

4-If NASA were to set up dedicated comms sats, it would probably come from HEOMD - the human spaceflight directorate. For that to happen, then they'd need the funding to actually do human spaceflight, and then an extra couple hundred millions per year for the sats. Forces beyond NASA's control  determine that - the President, the OMB, and the Congress. That of course, is something to discus on a Space Politics thread, not here.

5-I agree with you that dedicated comms sats are needed, nevertheless, I believe that any further discussion about the need for two or more dedicated comms sats and what they would look like belongs here:
SpaceX Mars communication constellation
It's a SpaceX thread, not a NASA thread, but my understanding is that the two are talking with each other about it. I'd be surprised if there wouldn't be collaboration. It would almost certainly be a public-private partnership, just
like the future of TDRS:


3-They don't have to have a science mission. That's just the way it has been prioritized. A different leader could make a different decision. And there's other ways of parsing this problem, like having NASA decide to build a comm relay satellite and then offer a few spots for foreign partners to stick instruments on it. Of course, the US scientific community would complain, but somebody always complains about something.

3A-There are possible alternatives looming on the horizon. For instance, the Psyche spacecraft is based on a commercial comsat bus. It will also have a laser communications system. Although it will not launch until 2022, if the spacecraft works at Mars distance, and if that laser comm works at Mars distance, that basic spacecraft would be a possible choice for a mid-2020s Mars relay satellite.

4-We're not doing humans to Mars. It's off the table for NASA now, and it just isn't going to happen, by anybody. So HEOMD is not going to step up to do it.

5-If NASA needs a comm relay at Mars, then NASA is going to pay for a comm relay at Mars. They aren't going to sit around and pray that somebody else does it for them. Memories on this forum are short (squirrel!) but it wasn't all that long ago that some company indicated that it was going to send some big honking landers to the surface of Mars, and lots of people got the vapors and swooned and said that now that this was happening, we didn't need all of those silly NASA missions, like sample return. Well, hope is not a strategy, it didn't happen, and so we're back to where we always were--if NASA decides it needs it, NASA is going to have to procure it.

Now the positive development is that other countries are getting into the game. India is building another Mars mission, and NASA is going to want to put a relay package on that one. China is building a Mars mission, and there is a possibility that maybe some cooperation could happen there. So there are other assets coming along that could help. And if some private company decides to use their own money to send stuff to Mars, I'm sure NASA would ask to put a relay package on that as well. Pigs could also grow wings. But that's enough for now.

Offline ccdengr

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Re: Opportunity rover updates and discussion
« Reply #110 on: 09/03/2018 01:17 AM »
None of this OT discussion about comm orbiters affects Opportunity at all.  People might try reading https://trs.jpl.nasa.gov/bitstream/handle/2014/37750/05-0557.pdf for some details about how MER communicates in fault states, especially Figure 2.

Once the rover loses its clock, it becomes much more unlikely that the scheduled UHF comm windows will happen to hit an actual overflight, making communication direct to Earth the only practical way of recovery.

Remember that the mission was only supposed to last for 90 days, and they only spent so much effort on fault protection (though they certainly seem to have covered the bases reasonably well, it's possible that a flaw in the fault protection scheme rather than an actual hardware failure was responsible for the loss of Spirit.)

Offline speedevil

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Re: Opportunity rover updates and discussion
« Reply #111 on: 09/03/2018 10:14 AM »
Once the rover loses its clock, it becomes much more unlikely that the scheduled UHF comm windows will happen to hit an actual overflight, making communication direct to Earth the only practical way of recovery.
Resisting commenting on the comms  as there are other threads for that

I guess in principle, a little math and a few observations could nail down the time quite well - though it would require more of the vehicle to be functional.
Find ecliptic plane during day (path of sun). Observe at early morning/evening to find three of venus/mercury. At night to find earth/jupiter/saturn.

Opportunity viewing comet Siding Spring

It would be a moderate amount of extra code, and require basically every part of the rover to be working.

Offline Archibald

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Re: Opportunity rover updates and discussion
« Reply #112 on: 09/03/2018 03:21 PM »
You said daffodils the last time... ;D

Sometimes even strawberries.

Still better than smelling elderberries (and being a hamster)
...you have been found guilty by the elders of the forum of a (imaginary) vendetta against Saint Elon - BLAAASPHEMER !

Offline ccdengr

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Re: Opportunity rover updates and discussion
« Reply #113 on: 09/03/2018 03:46 PM »
I guess in principle, a little math and a few observations could nail down the time quite well...
In theory, maybe, but it's both overkill and beyond what the MER hardware could do IMHO.

All that's needed, since the orbiters are in sun-sync orbits, is a solid way to determine the local solar time.  MER can't even do that reliably since all the data it has in a fault state is solar power production (it doesn't try to point its cameras in this state to do sun finding).  You don't want your fault protection to rely on lots of stuff working or take multiple sols to switch states.

In practice, I suspect that the orbiter ephemerides change enough over time that even knowing the LST isn't sufficient to predict comm windows indefinitely.  Again, the mission was designed for a 90-day lifetime.

Online Svetoslav

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Re: Opportunity rover updates and discussion
« Reply #114 on: 09/12/2018 06:06 AM »
NASA begins the 45-day period to attempt actively commanding Opportunity:

https://www.jpl.nasa.gov/news/news.php?feature=7227

Online theinternetftw

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Re: Opportunity rover updates and discussion
« Reply #115 on: 09/12/2018 08:55 AM »
Here's a very long form Planetary Society post on the whole thing.

It's a ton of information and a very confusing combination of intimations.  A lot of rah-rah-rah, everything is fine, everyone is on the right side and doing the best thing verbiage.  And then there's reporting like this, on the 1.5 Tau and 45-day numbers:

Quote
These are among the toughest times in planetary exploration. Callas was under pressure “to plug a financial drain,” according to a source with knowledge of the situation. “His numbers are technically defensible, if not technically optimum. And they are reasonable and acceptable to people whose concern is the money.”

As Deputy Principal Investigator Ray Arvidson, of Washington University St. Louis is wont to say: “It could be worse.”

Hopefully reality is filled with more of the "we will do the right thing" bits of the article such that they greatly outnumber instances of the above.

And for what looks to be some very good news, it looks like it's already in the mix that at least some active commanding will be done all the way to January.  From the Opportunity status update page:

Quote
No signal from Opportunity has been heard since Sol 5111 (June 10, 2018), though NASA has approved a strategy for listening for the rover through January of 2019.

It is expected that Opportunity has experienced a low-power fault and perhaps, a mission clock fault and then an up-loss timer fault. The science team continues to listen for the rover either during the expected fault communication windows or listening over a broader range of times using the Deep Space Network Radio Science Receiver.

The science team is also sending a command three times a week to elicit a beep if the rover happens to be awake, and will soon be expanding the commanding to include "sweep and beeps" to address a possible complexity with certain conditions within the mission clock fault. These will continue through January of 2019.

The dust storm on Mars continues its decay with atmospheric opacity (tau) over the rover site continuing to decrease. Once the tau has fallen below an estimated measurement of 1.5 twice - with one week apart between measurements - a period of 45 days will begin representing the best time for us to hear from the rover.

This also represents the best time to attempt active commanding during a specific mission clock fault condition. Back during the attempted recovery of the Spirit rover, a technical issue required the team to actively command the rover to communicate. Opportunity has no such issue; if we hear from it, it will likely be from listening passively as we have been, and as we will continue to do through January.

We will also actively attempt to command the rover to communicate during the 45-day listening period to cover the clock fault condition. After that, we will report to NASA on our efforts.

The "report to NASA after 45 days to review future plans" bit is a change as well, intimating flexibility.  Which could be good or bad, depending on if such a review is designed to "do the right thing" or not.

Online Svetoslav

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Re: Opportunity rover updates and discussion
« Reply #116 on: 09/15/2018 06:05 AM »
They're currently performing a Sweep&Beep maneuver. Meanwhile DSN detected a carrier lock two hours ago. Trying to figure if it's another false alarm... or perhaps, maybe they got lucky...

https://twitter.com/dsn_status/status/1040813778147926016
« Last Edit: 09/15/2018 06:05 AM by Svetoslav »

Online Svetoslav

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Re: Opportunity rover updates and discussion
« Reply #117 on: 09/15/2018 06:13 AM »
... and I have an answer from Michael Staab: Negative.  Signal strength is too high for Opportunity.

https://twitter.com/AstroStaab/status/1040845967233150976
« Last Edit: 09/15/2018 06:15 AM by Svetoslav »

Offline Eosterwine

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Re: Opportunity rover updates and discussion
« Reply #118 on: 09/18/2018 07:58 AM »
Looks like we just had another false detection, this time with the MAVEN orbiter briefly showing as Opportunity .

Offline Eosterwine

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Re: Opportunity rover updates and discussion
« Reply #119 on: 09/19/2018 07:48 AM »
Another uplink attempt currently in progress.    Does anyone know if Opportunity, assuming it is now operational of course, is supposed to respond immediately to one of these uplink attempts?

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