Venus seems to be finally receiving some of the attention it deserves.

Though not included in this latest batch of missions, perhaps we are
not too far from the day when a new generation of balloons or
even drones will be roaming the atmosphere.

speaking of which, anyone has any "hard" information (papers, abstracts etc.) on the private Rocket Lab Venus mission? other than, I mean, the articles in online media saying that it is being studied with little or no real information...

beside, being old enough to remember private missions which never took off including ISELA, Lunacorp, NEAP, Red Dragon and many more I am not holding my breath for this one

No, it's still happening. Not a paper (since it's a private mission), but there is a recent interview with Peter Beck here with a few more details (at 5:20 he mentions ~200 seconds in the atmosphere with a tunable laser spectrometer).

https://www.youtube.com/watch?v=U7iVs0Cq84M

This round of missions will return most of its data in the timeframe of 2029-2034. Then the scientific priorities should define what comes next.

A long-life seismic station (or network) will certainly be a priority if and when it's feasible. In other respects, it's frankly hard to say what missions will make sense in the 2040s until we have results back from the three missions that were just approved.

A potential line of exploration will depend on whether or not the tesserae contain ancient surface from a distinct earlier epoch when Venus was fundamentally a different planet. That's what Curiosity and Perseverance are doing at Mars. But you can't plan that until you know that it's even there to explore. Maybe all the tesserae contain such terrain. Maybe 1% of them do and we have to hunt for that 1%. Maybe 0% do and it's just chaotic, broken-up versions of what is in the plains. Maybe spectroscopy helps us identify such terrain and maybe it doesn't. Maybe we would want to have an airplane below the clouds map visible+IR spectrometry during the daytime or IR emissivity at night.

Roughly speaking, this is like the state of Mars exploration in 1992. Nobody then could have known that twelve years later we'd be examining the layers of sedimentary rock on Mars. But for us to do that, the planet has to have sedimentary rock, and Venus is still an enigma.

John, I think that you are largely correct. Ambitious follow up missions to Venus will build on what V, D+, and EnV tell us. However, I would be surprised if there weren't some simple high temperature landers sent in the next 15 years, especially if one or more of the orbiters have a communications relay added. The small landers would both do unique science and would demonstrate the emerging technologies.

While I have no insight into the thinking of the Venus Decadal panel, I'm thinking that once the hangovers have retreated that they will focus on technology development and perhaps demonstrations to have that next generation of missions ready.

Possibly even before 1992, in terms of surface mapping resolution. As I understand it, the best Magellan resolution is 100 m / pxl or so.
Surface imagery of better quality than that was not available for Mars until 1976.

Let's say that Magellan global radar has a resolution of 75 m/pix (a little bit of oversimplification but not wildly unfair). VISAR https://www.hou.usra.edu/meetings/lpsc2020/pdf/1449.pdf claims 30 m/pixel resolution globally and 15 m/pix in small targeted regions. So that's a fair approximation of what Viking gave us for Mars. It took another 10x increase in resolution provided by MOC to yield the results John is talking about.

Viking orbital imagery was very evolutionary, not revolutionary, from Mariner 9. And at least as far as orbital radar is concerned, these missions will likely be evolutionary from Magellan if the Mars experience is applicable (which I admit it may not be.)

Inarguable points, Mike, and I won't overly press the comparison between two situations. The spatial resolution is certainly in favor of Mars but I'll add that Venus exploration now is – possibly – matched with or beyond on Mars exploration in the Nineties in two ways. One, the emissivity data from the three upcoming missions will strive to accomplish what TES delivered for Mars, and this might be decisive in some way even if spatial resolution is lacking, but admittedly, this layers speculation on top of speculation: Perhaps emissivity will not tell us as much as we hope and we don't even know what we're looking for yet. Secondly, while the first three Mars landings were on flat, comparatively boring locations (and the fourth, incredibly flat, but not at all boring), the Venera and DAVINCI+ landing sites are pretty daring and even if they have been the equivalent of blindfolded dart throws, they've moved quickly towards the possible objectives of some of the more exciting terrain. It also occurs to me, for the first time, that the upcoming missions might place Venera surface data into much more meaningful context after the fact.

Venus is certainly more challenging than Mars on the whole, and it may not even be possible – ever – to achieve a knowledge of Venus comparable to our current knowledge of Mars, not only because of the obscuring clouds and harsh conditions but because its ancient surfaces may simply be obliterated. Beyond that, what we're even looking for remains speculative. I am being Mars-o-centric in speculating that we might eventually look on Venus for exactly what we're now exploring on Mars – the remaining traces of a more earth-like past. But who knows?

Venus exploration will always lag far behind Mars'. It is, if you will forgive the bad pun, a hellish place to study. MRO's context camera will outperform the radar instruments of both VERITAS and EnVision by an order of magnitude. The emissivity composition measurements will have a handful of spectra and 50 *km* resolution (although that may be improved with time by over sampling). We simply can't compare the two in terms of resolution - Mars will always be favored.

Rather, I think, we need to accept Venus for what it is. V and EnV will provide an order of magnitude improvement in resolution (Magellan resolutions are more typically quoted as ~300 m, with some limited areas at ~75 m). V will improve topographic resolution by at least one magnitude, perhaps two. Both V and EnV will be able to detect subtle changes in topography to look for activity.

Venus is one of four terrestrial planets, it's been overlooked (with BepiColombo, Mercury will be much better studied). The question, in my mind, isn't whether Mars, or the moon, or Mercury can be studied at higher resolution, but what can be done with Venus. These missions hugely move the goal posts.

Having spent more than a small amount of time working with the full-res F-BIDR products and even the raws back when the mission was still running, anyone who would say global coverage from Magellan is only 300m is not trying hard enough, IMHO.

Doing a more modern job of reprocessing the Magellan data would probably have payoffs for those brave enough to try it.

In the decades since I last worked on Magellan, full-res map products ("FMAPs") at 75 m/pix have been produced. See https://pds-imaging.jpl.nasa.gov/volumes/ma...an.html#mgnFMAP

Per the documentation,

I stand corrected

Here is a recent analysis of the tesserae suggesting that they may be the results of a fluvial past and further suggesting that the upcoming missions could answer that question.

https://www.nature.com/articles/s41467-020-19336-1

Hmm - what he says is "laser tuned mass spectrometer" which has me a little confused. DAVINCI has a tunable diode laser spectrometer, and a mass spectrometer. But these are quite different. So what is the 'one instrument' that Beck is proposing ? (There are laser desorption mass spectrometers, but that's different, that's a technique for getting solid material to volatilize to get it into the mass analyzer)

His reference to 200s in the atmosphere makes it sound like a 'Cupid's arrow' flythrough probe (that had been proposed in a previous VERITAS iteration
https://www.hou.usra.edu/meetings/lpsc2018/pdf/1763.pdf
https://trs.jpl.nasa.gov/bitstream/handle/2....pdf?sequence=1
(that proposal used a quadrupole ion trap mass spectrometer) There were concerns at the time that the high altitudes probed (to avoid excessive aerodynamic and aerothermal loads) might not be representative of the bulk atmosphere. There is also the issue, when organics are discussed, that the high relative velocities may break up large molecules, or that ablation products from any thermal protection cause a large contamination signal.

Anyway, it's exciting that a private mission is being contemplated. But the robustness of any scientific conclusions may depend on the specifics of the instrumentation and flight profile, and those details are not yet forthcoming. We'll see...

I don't disagree that more might be wrung out of Magellan data that the standard products at the time, but it is a simple fact that in its elliptical orbit, Magellan's resolution was highly latitude-dependent. Everyone quotes the 75m low-latitude value* as the 'headline to beat' with a new mission, and a global map product is obliged to have that pixel scale to not lose information. But that doesnt mean the 75m was achieved everywhere. Maybe 300m everywhere undersells the mission, but 75m everywhere oversells it.

It is worth recalling that the stated goal of VOIR / VRM / Magellan was to map Venus as well as Mariner 9 mapped Mars. Which it did. But there has been a lot of catching up to do since, thanks to your cameras... ;-)

Anyway VERITAS and EnVision will do much better than Magellan, in dimensions (NES0, polarization, InSAR etc. as well as resolution) so there will be discoveries aplenty..

This is a general question about the atmospheres of Venus, Earth, Mars, and Titan. Can someone explain how Mars and Venus are both primarily carbon dioxide and little nitrogen. On the other hand, (before life began on the planet) Earth's atmosphere was largely made up of nitrogen and carbon dioxide gases. Titan is primarily nitrogen. How come Earth's primary atmospheric component is nitrogen when Mars and Venus has hardly any. And why is Titan's so similar to Earth's and not Carbon Dioxide like Mars and Venus?

Short and probably too simple answer: there's lots of N2 on Venus, just not much fractionally. CO2 was removed from the early Earth's atmosphere by formation of solid carbonates (CO2+H2O+mineral reactions). This didn't happen on Venus, perhaps due to lack of water. Titan is so cold that CO2 freezes out so it can't be in the atmosphere. Why Mars has a lot of CO2 and few carbonates (since water was present on early Mars from most evidence) is still something of a mystery.

My turn to oversimplify. Venus' atmosphere is .035 nitrogen. Surface pressure around 92 earth atmospheres. Multiplication gives Venus an atmosphere of nitrogen that is 3.22 times higher pressure than earth's nitrogen/oxygen atmosphere if you removed all the CO2, even with the slightly lower gravity. Under earth gravity the pressure would increase further by around 10%. So, assuming this is a good enough approximation... yeah, Venus has plenty of nitrogen. Even with a surface area 10% smaller than earth, Venus should have around three times the amount of atmospheric nitrogen that we do. Therefore my own question would be... why so much?

Turning to studies of the interior, balloon-borne infrasound detection is considered as a means of seismic sounding:

https://www.jpl.nasa.gov/news/nasa-balloon-...next-stop-venus

It's a neat idea, sure. But determining that you have detected a signal above the background in quiet conditions at 3km altitude above California, when you know from a dense seismic network that there was a quake with given characteristics at a given time, is one thing. Floating near the turbulent cloud tops of Venus, where the infrasound background is likely high and poorly characterized, and being able to confidently attribute a signal in there to seismic activity on the surface, would be an altogether different proposition......

Venus Life Finder Mission Study

The Venus Life Finder Missions are a series of focused astrobiology mission concepts to search for habitability, signs of life, and life itself in the Venus atmosphere. While people have speculated on life in the Venus clouds for decades, we are now able to act with cost-effective and highly-focused missions. A major motivation are unexplained atmospheric chemical anomalies, including the "mysterious UV-absorber", tens of ppm O2, SO2 and H2O vertical abundance profiles, the possible presence of PH3 and NH3, and the unknown composition of Mode 3 cloud particles. These anomalies, which have lingered for decades, might be tied to habitability and life's activities or be indicative of unknown chemistry itself worth exploring. Our proposed series of VLF missions aim to study Venus' cloud particles and to continue where the pioneering in situ probe missions from nearly four decades ago left off. The world is poised on the brink of a revolution in space science. Our goal is not to supplant any other efforts but to take advantage of an opportunity for high-risk, high-reward science, which stands to possibly answer one of the greatest scientific mysteries of all, and in the process pioneer a new model of private/public partnership in space exploration.

The paper talks about the VLF Rocket Lab mission in sections 2 and 3 (pages 15 to 23).

The rest of the paper is even more interesting, talking about the proposed privately funded Venus Life Finder Mission (sections 4 and 5, pages 24 to 33) and the later proposed Venus Atmosphere Sample Return Mission (sections 5 and 6, pages 42 to 52).

Is there any info on whether mission planners expect or need the Davinci+ descent probe to survive on the surface for any length of time?
The mission CGI is amusingly coy on that one as the probe disappears behind a rock!

Obviously we are talking about minutes not hours considering the conditions there, and yes, I know that imaging on the surface probably wont
happen if the probe lands upright (the imager being on the underside i think), but what about the other instruments?

I guess I was hoping for a Huygens-like surface surprise.

Presumably there are limits on how long the orbiter and probe are in line of sight too?

P

"The DAVINCI+ probe will also descend over a tessera called Alpha Regio, taking up to 500 images as it falls to the surface. Although the spacecraft will eventually be destroyed, there is a small chance that it could survive on the surface for several minutes before it is wiped out by the intense pressure and temperature. These pictures of the tessera could be enlightening. “Our final images should have a resolution of tens of centimetres,” says Garvin."

https://www.nature.com/articles/d41586-021-01634-3

Thankyou!

P

The mission objectives do not require survival of impact. (as was the case for Pioneer Venus, and Huygens. I was heavily involved in the assessment of post-impact survival and operation of the latter.)

I guess in terms of expectation, you could consider that contact was lost at impact with 3 of the 4 Pioneer Venus probes (quite possibly simply by tipping over and depointing the antenna, rather than due to damage) whereas transmissions from the 4th were received for another hour or so until it got too hot. So maybe there's a 25% chance of continued operation. You could argue that the prior info on the terrain is that it may be rougher than average, so that reduces the odds a little.

In any case (as for Huygens) the relay spacecraft gets too low in the sky to sustain the radio link about 20 minutes after landing even if the probe is upright and still transmitting, so it wont be a long surface mission. And if the probe is upright, then the camera window is embedded in the dirt, so the images will not be exciting.

Ralph

Thankyou Ralph,
its always a pleasure to see your posts,

Id forgotten that one of the PV probes had survived for that long.

Im hoping for a surprise outcome, a good one, even if it is only 20 minutes.

P

Anyone on this forum know where the atmospheric sample port is located on this probe. If it would not be embedded in the dirt, then additional or extended composition measurements on the surface might be made.

I suspect that the other good use of any post-impact time might be to relay additional descent imaging data.

FWIW, the most important compositional measurements made by DAVINCI+ will be for the heavier inert gases, krypton and xenon, and should have no variations owing to altitude near the surface. Any measurement made in the final few km of the descent will be perfectly adequate. For those who haven't read about it, the methodology that will give great precision over previous measurements is quite clever: First, the composition of a sample of unaltered venusian atmosphere will be made, then chemical processes will remove most of the CO2 and N2 and a compositional measurement of the remaining gases will have much higher precision for those; finally, the sample will be cooled to the freezing points of krypton and xenon, the remaining gases blown way, and a measurement of the Kr+Xe only will be made, pinpointing the isotopic abundances. This will answer questions about the formation of Venus's atmosphere and speak to an outstanding mystery regarding the xenon isotopic abundances in Earth's atmosphere!

https://www.nasa.gov/feature/goddard/2021/davinci-vms

If there are any atmospheric compositional gradients right at the surface, I'm sure we wouldn't mind knowing about them, but the big questions will already be investigated before landing.

DAVINCI+ has a bowl shape and it will descend pretty slowly. Every image from Venera showed rocky rather than dusty or powdery surfaces, so I doubt if there's much chance of the surface making a tight seal against any atmospheric input port, should the craft survive landing.

DAVINCI uses a sapphire camera window to handle the intense heat and pressure, according to this site the Venera camera windows were quartz. one wonders if saphire was chosen because the thermal expansion characteristics might perhaps be more favorable across expected deep space vs surface conditions?

Could be window transmission. Sapphire is pretty transparent over 0.14-6 microns vs quartz 0.17-3.5 (give or take a bit, depending on window thickness).

The same page indicates that the quartz's refractive properties required a compensatory lens to be added to the design. If sapphire does not require that, then that would be one justification.

New paper on the DAVINCI mission: https://iopscience.iop.org/article/10.3847/PSJ/ac63c2/pdf

Three new papers on the ArXiv re life finding mission concepts to Venus focusing on entry probes and balloons.

First paper features details about Rocket Lab's tiny entry probe 'demonstrator' scheduled for launch next year.

https://arxiv.org/ftp/arxiv/papers/2208/2208.05570.pdf
https://arxiv.org/ftp/arxiv/papers/2208/2208.05579.pdf
https://arxiv.org/ftp/arxiv/papers/2208/2208.05582.pdf

P

China has a proposed Venus mission which, given the brief description given here, seems like it would overlap in goals with Veritas and Envision, and if selected, would arrive at about the same time as Veritas. The orbit would be somewhat higher so perhaps the radar resolution would not be quite as good as Veritas, but there are no hard specs here.

It seems a bit odd that after no U.S. missions to Venus in over four decades that China would even contemplate sending a similar mission at almost the same time. Then again, this is from a list of many proposed missions, so maybe the similarity is coincidental.

https://www.space.com/china-venus-mission-details

Lori Glaze just announced that fallout from the Psyche launch delay has pushed the VERITAS launch to 2031

If all else remains the same, then it seems like DAVINCI+ will make its descent before VERITAS maps the area of its landing site. That seems like it doesn't really change which things we'll learn, just the order in which we learn them.

After reading the press release on the problems found with the Psyche mission development, many of them relate to staff and expertise drain at JPL. VERITAS is a second JPL mission, so part of the delay could be to deal with the issues at JPL (as well as handle the increased cost of the Psyche mission from its delay).

DAVINCI, as I recall, is being developed by Goddard and so at least the JPL issues wouldn't apply. (Although NASA may review all centers for these issues.)

A 2-year launch delay. (To answer the question I had reading this.)

My recollection is that VERITAS was aiming for a 2028 launch.

I think the reasoning is that the bulk of the MSR development (launch 2028) needs to be completed before switching to the ramp up for the VERITAS development.

A 2031 launch would be the same as EnVision is believe. If I remember correctly, it will take ~2 years for EnVision to reach Venus and then do aerobraking to achieve the mapping orbit. Probably something similar for VERITAS. So, I' expecting the science mission for VERITAS to begin around 2033 (at least until we see a plan from the VERITAS team).

And the announcement said that the VERITAS launch would be *no earlier than* 2031, not that 2031 was a firm date.

This still indicates (the old plan, no doubt) a July 2028 arrival for VERITAS, which would mean launch around the end of 2027.

https://solarsystem.nasa.gov/missions/veritas/overview/

While cruises to Venus of about seven months are possible and typical, note that Magellan, when plans were changed by the domino effect of Challenger and Galileo, ended up taking a long cruise of over a year to Venus.

Not sure what source I had yesterday, though I suspect I was confused.

Better:

https://www.nasa.gov/mediacast/gravity-assi...with-lori-glaze

I likely confused the two, adding a year. So-- ya'll are right. ~3yr delay to VERITAS launch.

More bad news for VERITAS - their funding was virtually zero'ed out this year as well. Flight delays I've seen before - but slashing the funding and stopping development is something I can't recall seeing previously...

That's worrisome about VERITAS.

The notional timelines for the other missions are for a 2031 landing for the DAVINCI probe; some flyby science will precede that around January 2030.

EnVision will launch in 2031 or later, and would complete its first venusian day of science about three years later, after cruise and aerobraking.

The original VERITAS timeline would have had it returning results before any of that, but now it seems like it might be operating more or less simultaneously with EnVision. While any delay is disappointing, I'm not sure that I sense the specific problem that the article implies when it says that VERITAS data would have been used to "calibrate" EnVision results. I suppose that VERITAS data could have been used to determine targets for EnVision high-resolution radar mapping, but EnVision will also be able to perform that role for itself, and Magellan data already exists, so it appears that the real misfortune here is in delaying science rather than losing any. Maybe from the standpoint of real-time observable surface change it would be nice to see a snapshot of Venus from a few years before EnVision arrives, but if there's real-time change on that timeline, then there'll almost certainly be plenty of change to notice anyway, given the decades since Magellan.

With seven more years before DAVINCI first approaches Venus, the long wait for NASA's return to the planet continues.

Recently, EnVision was formally adopted into ESA's science programme. Now the corresponding Definition Study Report, the so-called Red Book, has become available.

Good news - VERITAS is back! Funding was restored in the latest budget, and it's now on NASA's schedule with a 2031 launch date

Wonderful news.

As it stands, EnVision is also planned to launch in 2031, so we'll have the ludicrous circumstance that decades after the last radar-mapping mission to Venus, two will arrive at the same time. But better late than never and better two than one! (Three with the earlier arrival of Davinci.)

There is an apparent cost: the launch of the DAVINCI mission has been delayed.

The budget request doesn't give a reason for the DAVINCI delay, but it may have been to free up a funding wedge for VERITAS.

Here is the language from the budget request:

"This budget supports the VERITAS mission to launch during an available Venus opportunity in
2031-2032. NASA reduced the future Discovery and Planetary SmallSat budgets which will delay the
release of the next Discovery and SIMPLEx AOs to no earlier than FY 2026. This budget also delays the
DAVINCI mission launch from 2029 to an available Venus opportunity in the 2031-2032 timeframe."

DAVINCI will release its probe on it's third encounter with Venus (the multiple encounters allow the probe to be targeted to the desired descent region).

I believe that VERITAS will enter orbit on its first Venus encounter, but there will be a delay to the prime mapping mission for an extended period of aerobraking. EnVision's prime mission will be delayed for the same reason.

For all three missions, it appears that their prime data collection will begin in the 2033-2035 period.

At the SMD Community Budget Town Hall meeting, Lori Glaze emphasized that the delay of DAVINCI is "purely a budget-driven decision".