NASA - MAVEN - updates and discussion

[Lee Jay]

That seems like a huge delta-v change. Maybe they made an error in their calculations and it is not that big.

There's no way there's enough prop on board, even if all released through a proper engine nozzle in the perfect direction, to make this happen, right?  It would have to be clobbered by something which, to me, seems inconsistent with the LGA still working.

[djellison]

I have huge respect for the AMSAT DL folks - but I'm a little skeptical of this one.

From their last post today - https://bsky.app/profile/amsat-dl.org/post/3ma6xk2dgcc2s

Our own preliminary doppler profile shows that Maven's orbit period is now 1h52m instead of 3h30m.  That would be a huge discrepancy.  112 minutes period gives SMA of 3659km. Something odd is going on...

112 minute orbital period is the orbital period of MRO.   It's also a dramatically different orbit from where MAVEN was before whatever anomaly occured.  It would take a LOT of Delta V to get from that ~200 x 4500km orbit down to something under 2 hours like ~250 x 320 of MRO..... 800 m/sec - something in that ballpark.   I don't believe MVN had enough propellant for that...or the sort of event required to do that externally isn't going to have an intact spacecraft afterwards.

My suspicion is that AMSAT DL have the wrong spacecraft, or the wrong orbit.

[Lee Jay]

That seems like a huge delta-v change. Maybe they made an error in their calculations and it is not that big.

There's no way there's enough prop on board, even if all released through a proper engine nozzle in the perfect direction, to make this happen, right?  It would have to be clobbered by something which, to me, seems inconsistent with the LGA still working.

Yeah, I'm just an armchair non-expert here, but I know enough about orbital dynamics that major changes don't happen fast, and they don't happen accidentally.

Okay, so if the spacecraft couldn't have done it, and a hit by a meteor or something wouldn't have left an intact spacecraft to be broadcasting, that leaves two possibilities I can think of - they got it wrong somehow, or it was aliens.  So, it must have been aliens.

[DaveS]

That seems like a huge delta-v change. Maybe they made an error in their calculations and it is not that big.

There's no way there's enough prop on board, even if all released through a proper engine nozzle in the perfect direction, to make this happen, right?  It would have to be clobbered by something which, to me, seems inconsistent with the LGA still working.

Yeah, I'm just an armchair non-expert here, but I know enough about orbital dynamics that major changes don't happen fast, and they don't happen accidentally.

Okay, so if the spacecraft couldn't have done it, and a hit by a meteor or something wouldn't have left an intact spacecraft to be broadcasting, that leaves two possibilities I can think of - they got it wrong somehow, or it was aliens.  So, it must have been aliens.

Well, Jonathan McDowell postulated another hypothesis: https://twitter.com/planet4589/status/2001364795858317601#m

My guess would be thuster accident pushing perigee into the atmosphere followed by rapid undesired aerobraking to reduce apoares from 4500 km to 450 km. Would suggest imminent reentry - important to try and measure the period rate-of-change to test this

[s_wood]

I have huge respect for the AMSAT DL folks - but I'm a little skeptical of this one.

From their last post today - https://bsky.app/profile/amsat-dl.org/post/3ma6xk2dgcc2s

Our own preliminary doppler profile shows that Maven's orbit period is now 1h52m instead of 3h30m.  That would be a huge discrepancy.  112 minutes period gives SMA of 3659km. Something odd is going on...

112 minute orbital period is the orbital period of MRO.   It's also a dramatically different orbit from where MAVEN was before whatever anomaly occured.  It would take a LOT of Delta V to get from that ~200 x 4500km orbit down to something under 2 hours like ~250 x 320 of MRO..... 800 m/sec - something in that ballpark.   I don't believe MVN had enough propellant for that...or the sort of event required to do that externally isn't going to have an intact spacecraft afterwards.

My suspicion is that AMSAT DL have the wrong spacecraft, or the wrong orbit.

Yeah, it'll be the wrong spacecraft

They've been routinely looking for MAVEN on the 70m station's all of last week and this.
I can't believe that dsn saw nothing but these guys did.?

[StraumliBlight]

https://bsky.app/profile/amsat-dl.org/post/3ma7fvuayvc2l

Q: How do you know this is MAVEN and not one of the other orbiters?

AMSAT-DL: Each Orbiter does have different frequencies.

[s_wood]

https://bsky.app/profile/amsat-dl.org/post/3ma7fvuayvc2l

Q: How do you know this is MAVEN and not one of the other orbiters?

AMSAT-DL: Each Orbiter does have different frequencies.

yes, but they're not that far apart, its quite possible its one of the side lobes on MRO


especially given the orbit period they have worked out is almost exactly MROs

[catdlr]

https://x.com/amsatdl/status/2001389860590887204

AMSAT-DL
@amsatdl
·

Replying to
@amsatdl
MRO is in a ~250 km to ~320 km orbit around Mars, which results in the same orbital period we observed. It is likely that we may have received some harmonic frequencies from MRO and not the carrier from Maven.  Will investigate further..

[djellison]

AmSat DL has confirmed that what they saw was MRO, not MVN.

https://twitter.com/amsatdl/status/2001601615103492214

AMSAT-DL
@amsatdl
UPDATE: #MRO and #MAVEN  downlink frequencies are 6 MHz apart, so they should normally not interfere with each other. However, the events we saw yesterday and today as of timings and frequency doppler agree with Horizons/MRO exactly. In the attached screenshots we can see “spurious” and “harmonics”. The spurious signals are local interference, but the harmonics are obviously from MRO and very close to the expected Maven frequency. What was thought to be “Maven” is in fact MRO. Proof test by off-pointing our 20m antenna from Mars, but also acid tested when MRO disappeared behind Mars (LOS) – same effect.

On December 15th NASA wrote in the Maven blog: “Although no spacecraft telemetry has been received since Dec. 4, the team recovered a brief fragment of tracking data from Dec. 6 as part of an ongoing radio science campaign. Analysis of that signal suggests that the MAVEN spacecraft was rotating in an unexpected manner when it emerged from behind Mars. Further, the frequency of the tracking signal suggests MAVEN’s orbit trajectory may have changed”.
So, they might have seen those harmonics from MRO as well as they have not received telemetry from Maven since December 4th and it might well be that Maven is still in its nominal orbit, but having some sort of electrical power outage.  So hopefully they will be able to "reboot" Maven soon...

[woods170]

AmSat DL has confirmed that what they saw was MRO, not MVN.

This is a fine example of why organizations should triple-check their stuff before making a sensationalist post on social media. How the h@ll did they think they were able to "hear" MAVEN while NASA couldn't? AMSAT DL just made themselves look like a bunch of clowns.

Literal amateurs.

[Kaputnik]

I'm confused now.
Have some signals definitely been detected from MAVEN?

[LouScheffer]

AmSat DL has confirmed that what they saw was MRO, not MVN.

This is a fine example of why organizations should triple-check their stuff before making a sensationalist post on social media. How the h@ll did they think they were able to "hear" MAVEN while NASA couldn't? AMSAT DL just made themselves look like a bunch of clowns.

Literal amateurs.

It's not just amateurs.  There is a certain professor at Harvard who's constantly doing exactly this, and he gets paid for it.

And the solution, in my opinion, is not to refrain from posting.  Early notice is good, just in case something is real.  But they should be super explicit about what they saw, and what they inferred.  If they said "We were looking for a signal on the Maven frequency and saw this.  If it's really MAVEN, though, it's in a much different orbit than it was before it disappeared."  Same info as in their social media posting, but much less misleading.  And much less embarrassing when they, and others, figure it out.

[ccdengr]

Have some signals definitely been detected from MAVEN?

Not by AMSAT.  They cheekily suggest that DSN made the same mistake that they made and that DSN also detected MRO and not MAVEN, but since DSN knows what they're doing I think that's unlikely.  So I would assume the original signal that NASA reported was real.

[djellison]

But they should be super explicit about what they saw, and what they inferred.  If they said "We were looking for a signal on the Maven frequency and saw this.  If it's really MAVEN, though, it's in a much different orbit than it was before it disappeared."  Same info as in their social media posting, but much less misleading.  And much less embarrassing when they, and others, figure it out.

Yeah - like I said before - I have a lot of respect for AMSAT-DL and their work....but coming out the gate with "#MAVEN is still alive and transmitting on the low gain antenna!" is highly irresponsible. 

Since then - several times - they've inferred that the mistake they made ( wrongly identifying a harmonic of MRO as MVN ) is what the DSN did when finding a few mins of radio science data on Dec 6th.    I'm sure it's not their intent, but it comes across as pretty insulting with respect to the experience and capability of the MVN and DSN teams.

[MickQ]

I see that Maven is now not listed with the other Mars orbiters on DSN Now.

Does this mean anything ??

[djellison]

Does this mean anything ??

Sometimes you'll see it with other Mars spacecraft doing MSPA ( multiple spacecraft per aperture ) and sometimes you'll see it on its own and sometimes you wont see it at all.  Sometimes there will be other assets not in the DSN trying to listen in.

It doesn't mean anything, or to be more precise - people shouldn't infer meaning from its appearance or absence on DSN Now.

[s_wood]

Does this mean anything ??

Sometimes you'll see it with other Mars spacecraft doing MSPA ( multiple spacecraft per aperture ) and sometimes you'll see it on its own and sometimes you wont see it at all.  Sometimes there will be other assets not in the DSN trying to listen in.

It doesn't mean anything, or to be more precise - people shouldn't infer meaning from its appearance or absence on DSN Now.

exactly. Theres a carefully crafted schedule being executed here.

Also MSPA on DSN only has uplink for a single spacecraft, they've also been shuffling the other 4 orbiters around since the emergency was declared to give uplink and downlink for MAVEN, but they still need to talk to the rest.

[LouScheffer]

And the solution, in my opinion, is not to refrain from posting.  Early notice is good, just in case something is real.  But they should be super explicit about what they saw, and what they inferred.  If they said "We were looking for a signal on the Maven frequency and saw this.  If it's really MAVEN, though, it's in a much different orbit than it was before it disappeared."  Same info as in their social media posting, but much less misleading.  And much less embarrassing when they, and others, figure it out.

But they should not be posting to the general public. They should be checking that information with other sources. Other similar activities, like near Earth object detection, have internal communications processes and don't just dump information out into the public.

I respectfully disagree.  As a member of the public, I appreciate seeing the raw data, even if the interpretation is wrong.

In this exact incident, for example, I would love to see the JPL radio science data that showed MAVEN was still alive but spinning.  If there was a choice of just one policy for both groups (reveal everything, or wait until it's vetted by insiders), I strongly prefer the early public disclosure at the potential cost of later retraction.

EDIT:  In this particular case, we get the worst of all possible worlds.  The group with flaky data goes public, and the group that is solidly technically competent stays silent.

[daedalus1]

Updates?

[DaveS]

None so far.