Missions could see NASA spacecraft heading to Uranus and Neptune
physics-astronomy.com
physics-astronomy.com
All jokes aside, these missions are still pretty far off and article doesn't really go into depth of what this research can help accomplish for future generations. Thoughts?
Uranus was discovered by British-Hanoverian William Herschel [1] and named after the Greek god of the sky, Οὐρανός [2], which anglifies to Ouranos.
If I was doing a meeting with Paris colleagues I always tried to book the Uranus room so I could start the meeting with HILARIOUS comments like:
"Are you talking from Uranus?"
"How many people are in Uranus today?"
Based on what I've read, which includes a paper from a NASA (or was it JPL?) engineer, Venus' surface is not very hospitabl, but at a certain altitude it looks like an oasis in the Solar System:
Venus (at ~50-55 km altitude) / Mars (surface): (all stats from Wikipedia, and yes not always complete or comparable)
* Gravity: 0.9G / 0.38G
* Pressure: ~1 atm / 0.00628 atm (prevents liquid water)
* Temperature: 27-75 deg C / -63 deg C (mean)
* Shortest distance from Earth (for logistics): 40M km / 55M km
* Sunlight (energy): More than Earth / 43% of Earth
Also, oxygen and nitrogen are lighter than the CO2-heavy atmosphere, so a balloon of O2 and N2 would float conveniently at 50 km. The CO2 in the atmosphere also could be a valuable resource.
> Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid.
We know very little about it. Also, I'm sure you'll need to coat any probes/spacecraft to protect against the sulfuric acid.
> The water has probably photodissociated, and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field.
So basically same chance of water (maybe worse) as Mars.
> Venus (at ~50-55 km altitude)
So we'd have to have floating habitats even if we knew this zone was actually habitable (it's still a sulfurous environment). This also means much higher energy costs along with other logistical challenges.
> Shortest distance from Earth (for logistics): 40M km / 55M km
Yeah, but you're fighting solar winds so the question is how much less are the energy costs. Also, from a logistics perspective, communication might be important & the unfriendly atmosphere may pose additional challenges/costs.
Photovoltaic power might sound problematic at first in view of the long Venusian night (a single day lasts up to 116 Earth days), but at altitude there are strong jet streams and winds circulate around the equator roughly every hundred hours. So you're not stuck running on battery power for months on end, but you may need some maneuvering capability.
This is not to minimize the problems associated with activity in the Venusian atmosphere -- but it's not quite the impossible hell-hole it's been portrayed as.
You can't just drift there as if you're in a hot air balloon eating sandwiches and enjoying the view.
Venus might not be completely impossible, but it's still one of the less hospitable destinations in the solar system.
Also, smelly because of the H2S.
I think the real killer is that it's hard to build and maintain infrastructure when floating on balloons - much easier to run a spaceport on Mars, or to get to all the useful surface resource deposits. On Venus you'd have to build literal castles in the air, using only only what you can pull out of the atmosphere or ship in from orbit.
Not to mention Mars is at the bottom of a much shallower gravity well.
The big difference is you can fire off a rocket and get water to the ISS in comparatively shorter time and less fuel, which makes it feel much more challenging to get in the sky of Venus.
I obviously have no idea what I'm talking about here, but I'm thinking the continued challenges of floating -vs- hard ground will be very high. Plus we don't really have any direct experience with that, right?
But in the debate about Mars vs Venus, for me two things stand out:
- We can kick off a Mars terraforming project with our current level of technology. I've heard it said that within a few hundred years we can get it so that all you need outside is thermal protection and an oxygen mask. Reversing the situation on Venus will basically take Star Trek level tech.
- You can leave your habitat on Mars, get some rocks, and pile those rocks up to make more habitat. On Venus, you will have to basically "drill" down to the surface to recover any materials, and I don't think you can easily build dirigibles out of rocks and atmosphere as easily as you can build a hut.
Mars has many more advantages in comparison. For one you can build on the surface of the planet. There are many resources on Mars that can be exploited almost immediately and many others that can be exploited over a longer term: the atmosphere can be used to help produce rocket propellant, water can be used to aid in that as well. Things like iron/steel, glass, plastics, concrete, etc. can all be produced on Mars with a minimal industrial base within the first decade of colonization, with increasing quality and throughput over time. These things are important because they significantly advantage Martian colonies in terms of their ability to be partially self-sufficient and partially self-reliant in regards to expansion.
On Venus practically every ounce of material in the colony needs to be shipped from Earth, it's scarcely better than an orbital station. On Mars you can rely on local supplies for water, for propellant for the return trip, for fuel and oxidizer for ground machinery (mining vehicles) and emergency backup power. You can grow crops using Martian sunlight, Martian CO2, Martian water, Martian Nitrogen, and Martian soil. You can use solar energy for power and sunlight to grow crops as on Earth, the lower light levels are slightly misleading, Mars doesn't have routine cloud cover and has a thinner atmosphere so the average amount of watt-hours per area per day on Mars are very similar to what they are on Earth. You can use regolith for radiation shielding and in construction (building roads, for example). You can manufacture concrete, steel, glass, and plastics using local materials so that you can begin building things like habitats, industrial facilities, etc. using substantially locally produced materials while relying on Earth-produced components for only a subset of the mass of the things that get built, and an ever decreasing subset at that.
A Mars colony would be one that should grow in size and capabilities by leaps and bounds year over year as local industry and agriculture ramps up, as exploitation of local resources increases and improves, as techniques for making use of those local resources scale up and become increasingly sophisticated.
Venus just doesn't rate in comparison. Nobody has a design for how you'd build a floating habitat on Venus that would be reliable enough to trust for decades. One that could also serve as a spaceport for spaceships.
We have the technology to tackle Mars colonization now, it only requires following through on doing it. And Mars has the resources to make colonization a feasible concern that increases its ability to support a population, increases its level of technological sophistication, increases its industrial and agricultural base substantially every year, year after year, indefinitely. That's why Mars is such an attractive target. You can plant a civilization there in a way that you can't, with our level of technology, on the Moon or Venus.
You just pretty much described the ISS, but I get your point. That's in orbit around Earth. :P
Ambient pressure is a huge advantage: Liquid water doesn't boil away,
Caution: don't click unless you have nothing else to do today.
Super interesting paper. Turns out Voyager was the first spacecraft that could be reprogrammed "mid flight". In fact, if it wasn't for that we would have not gotten back images of Uranus or Neptune!
https://fermatslibrary.com/s/voyager-mission-telecommunicati...
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Probes are great, but I think many overestimate the amount of information they can genuinely provide. Even on Mars where we have had multiple rovers on the surface, there are still ongoing debates about things such as whether the streaks on the planet's surface are water, which NASA made a large announcement of, or indeed just sand which is where the latest interpretation stands. And that's for a very peaceful and close planet (in comparison to Uranus or Neptune) that we ostensibly have a great understanding of.
I don't really care what their goal would be, as long as it would be a goal that they could work towards - a base on the moon, a base on mars, expanding the ISS, or anything - preferably with a human element as that's what attracts people to space, and thus gets the money to make these missions become reality. But these probes are not really advancing society.
And here I would make an exception for things like the Kepler missions. Those were a directed mission with a specific, valuable, and new purpose that could (and did) provide information that substantially advanced society. Let's go shoot some probes off around Uranus and Neptune and grab some pics and atmospheric readings is better than nothing but it feels like spending funding for the sake of spending funding.
"I don't really care what their goal would be, as long as it would be a goal that they could work towards..."
and that link shows the basic four orienting science questions (right panel in blue text) - how did life begin, how did the solar system evolve, how did the planets originate, etc.
Those are the top-level questions that the National Academies panel doing the Decadal Survey arrived at and that motivates the portfolio of planetary missions that are planned. I would have linked to the Decadal Survey (overview at https://en.wikipedia.org/wiki/Planetary_Science_Decadal_Surv...), but the report itself is a very long pdf - and this gets into the strategy in detail.
For instance, the next Mars mission (Mars 2020) is set up to address the "life" question, and the "how did the planet [Mars] evolve" question, etc.
Think about SpaceX. What they've done should have been impossible. A private company operating on a shoestring budget revolutionized space in 15 years? That doesn't mean Musk is a genius, it means that our current space system is simply incompetent. There are certainly many reasons for this, including congress using NASA as a jobs program, but I think a lack of direction is also a major reason. 'Discovering how life began and evolved on Earth' as a mission statement is like a philsopher stating his goal is to 'discover the meaning of existence.' It's a goal that's so impossible and so broad that anything can be justified in its name.
'Easier' goals are in many ways much harder since you need to remain focused. And when NASA has focus they, at least in the past, have shown themselves capable of amazing things. Going from having never even put a man in orbit, to putting a man on the moon in a decade? Think about that, if you even can. In today's times that should seem completely unbelievable. And we should be capable of exponentially more now a days. And that is where we should set our sights. The point I'm getting at is that if you aim low, that's always where you're going to hit. Aim high and you might miss, but at least you're pointed in the right direction.
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As one brief aside, those mission statements immediately made me think of Oumuamua [2] -- that cylindrical weird interstellar object (it's exact nature is, and will likely remain unknown - the name translates to 'first scout', as the imagination might imagine) currently looping around the sun on its pass through and on its way out of our solar system. Being able to get ships and ideally humans onto that thing would be groundbreaking and actually go a long ways towards pushing those mission statements, abstract though they may be, forward. But our space program and technology is so backwards and dated that we're instead left watching jaws agape as arguably the single most relevant tracked celestial object lackadaisically (...as lackadaisical as 30km/s can be) laps us on its way on out of our solar system. It's again absurd that the primary interest in trying to perform an intercept with this object has come from the private industry. But hey, at least we'll know the wind speed in Uranus...
[1] - https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...
You mention the ambiguity of the animating goals. Part of this is just linguistic: of course you want to push down these top-level goals to more granular, 0/1 goals ("was there an ancient lake at this site on Mars?" Answer: yes). That's what the NAS report does. Now that we know how abundant water was on ancient Mars, we'd like to return samples to see if there was life. That's the next couple of missions.
You raise a worthwhile point, I think, about immediately-graspable 0/1 goals, like "man on moon". I see your point - but I'm really only here to talk about the unmanned program because my limited expertise covers part of that area.
You like SpaceX. So do I - two good friends left my lab to work there. But their achievement ("revolutionized space") is not unique. The little Mars pathfinder had about that much history. There are plenty of other examples over the same time period, like exoplanet discovery (as you noted), cosmology, and a host of Earth science stuff.
So to make this more clear, one reason I think what SpaceX has already achieved and especially what they plan to achieve is so revolutionary is because of how it would impact other programs. Like you mention one of NASA's big goals is a sample return mission. And this is going to be highly complex and highly expensive. The OSIRIS-REx mission mission is a billion dollar, 7 year mission to get 0.1-2kg of debris from an asteroid that comes within 0.0002AU of Earth with a 6 year period. That's really not reasonable. These missions would be trivialized with technologies such as the BFR. Such technology would also enable vastly greater scope and scale of these sort of missions. A Uranus orbiter will provide some science that might have some value, but it's not really advancing anything. The chance of revolutionary discovery is practically 0, and it will be unlikely to have a meaningful effect on future missions or projects.
Basically it feels quite odd that we're using technology that is comparable in both price and capability to what we were using the 70s. It's quite peculiar, and I think this has been the major hold up in us achieving much more in space. Imagine for a minute that it's 1969. We've just seen live footage of men walking and driving rovers on the moon. And I tell you that in 50 years NASA's vision for a flagship mission will be sending a probe to Uranus. And no man would ever leave low earth orbit again after 1972. Wouldn't you say something has gone very wrong? And this wrongness continues to persist, and I think it is because of this 'Well I have $x. What should I spend it all on?' as opposed to aiming for directed evolution and progress.
Mass produce satellites and space station modules instead.
I think with Trump the easiest sell would be more American manufacturing than a Uranus mission.
Now that there are several competitive and reliable commercial launch providers who maintain that know-how, we need to stop subsidizing bloated defense contractors and instead spend that money on buying launches and making satellites.
I agree there should be a balence but NASA shouldn’t have to solely rely on the likes of Space X. Bloated defense contractors are a symptom of the problem, look at the scope creep of the F35.
Is it the government contractors or unclear/ever changing requirements?
What's missing is a few more start-ups like SpaceX to totally crowd out the likes of Boeing from the contractor feeding trough.
They will never build in house and never have. Just like the military some large contractor will build the plane or spaceship according to their specs.
Boeing doesn’t create a figther jet and then sell it to someone. If space goes private it would be like this.