IAMA 022615 NL PSc PS A1A2A3 Q1 Europa TitanIAMA 022615 NL PSd PS A1A2A3 Q1 Europa Titan


[–]Universu 2 points 4 hours ago
Can humans live in Europa or Titan? What habitat would be needed to live there?

[–]BillAdkinsBill Adkins – The Planetary Society[F] 3 points 4 hours ago
Both Europa and Titan would be pretty inhospitable places to visit, much less stay to live. Issues
that would need to be addressed include intense radiation environment, extremely cold temperature,
lack of a source of energy, food, air, etc. Europa may have heat and water below the ice surface, but
getting through the ice would likely be a significant technical challenge. Titan is mostly methane
and ethane atmosphere, so that’d be pretty nasty. At this point, it’s technologically beyond what can
be done…and may remain that way for a long time.

[–]elakdawallaEmily Lakdawalla – The Planetary Society[F] 4 points 4 hours ago
Human exploration of Titan won’t happen anytime soon, but it’s fun to imagine. You could fly on Titan
by flapping your arms with the help of some very small wings, thanks to the dense atmosphere and low
gravity. Here’s one brain-bending thing about human exploration of Titan: like Earth, its atmosphere
is mostly nitrogen. But the next most common gas on Titan is methane, whereas on Earth it’s oxygen.
Human astronauts need oxygen to breathe, and they also need fuel to make machines move. On Earth, we
combust hydrocarbon fuel with the help of an oxygen atmosphere. On Titan, the oxygen that we’d have
to carry to breathe would also be our vehicle fuel, and it would combust with the help of the methane
atmosphere. It would also mean we’d be breathing a highly, highly flammable gas. Yikes.

[–]tsondie21 [score hidden] 3 hours ago
I was of the understanding that the energy needs of our current rockets mean that we are using liquid
oxygen along with rocket fuel as the atmosphere doesn’t have enough oxygen to support the combustion
requirements. Are you saying that on Titan, there would be enough atmospheric methane (or maybe so
little thrust required) as to not require any in-rocket fuel other than oxygen?

[–]elakdawallaEmily Lakdawalla – The Planetary Society[F] [score hidden] 34 minutes ago
Well, I’m not an engineer, so keep that in mind when I say: yes, that’s what I’m saying. If we have
the technology to get humans to Titan, then I’m sure we could take advantage of the 5% methane
atmosphere as a reducer to burn oxygen. We could make the oxygen from Titan’s crust, which is mostly
water ice.

[–]KubrickIsMyCopilot [score hidden] 3 hours ago
They are the most challenging potential habitats for humans, despite how much attention they get
scientifically. Titan’s atmosphere and hydrosphere are a weather hazard that you would have to deal
with constantly, and we don’t know what kind of weird chemistry can cause problems with human-made
technology. Plus it’s colder than colder.
And Europa’s bathed in radiation on the surface you don’t want to deal with, so you got to drill into
the ice even if just to make a habitat, But even then, challenge or trade or transportation with
anywhere else will be expensive because of all the radiation. All you got for you is ice and maybe a
little bit of organic stuff spewed up from below. Callisto is by far the best choice to live around
Jupiter. Very little radiation, either from Jupiter or the Sun or cosmically, because it’s protected
by the Jovian field instead of bombarded by it.

IAMA 022615 NL PSe PS A4 A5 Q2 ConstellationCubesatsIAMA 022615 NL PSf PS A4 A5 Q2 ConstellationCubesats


[–]Universu 3 points 4 hours ago
Why not deploy a constellation of cubesats by the hundredths instead of a single satellite in future
planetary exploration?

[–]BillAdkinsBill Adkins – The Planetary Society[F] [score hidden] 3 hours ago
Good question. Cubesats definitely have a role in planetary exploration exploration, since you can
deploy many and make multiple measurements simultaneously. They’re also relatively cheap. I think
cubesats have come a long way in the last 10-15 years and scientists and engineers are thinking of
novel applications for cubesats. I think cubesats have a very bright future. However, because of
physics, many missions require a large aperture (eg camera, telescope, antenna, etc.) that simply
cannot be done with a cubesat. The sweetspot will be to ahve cubesats working in tandem with larger

[–]jasonrdavis[F] [score hidden] 3 hours ago
CubeSat fleets are certainly a growing area. Planet Labs’ Flock 1 comes to mind
(https://www.planet.com/flock1/). I think a fleet of interplanetary CubeSats is an interesting idea
that has a lot of potential.
But one thing important to note when discussing the future of CubeSats is that while we’re getting
good at flying CubeSat missions in Earth orbit, we still haven’t applied the technology elsewhere.
And it’s a little harder than you might think.
Take transmission capability, for instance. LightSail’s little radio transmits at about one watt —
that’s on the order of a cell phone. We’ll be able to pick that up at small ground stations in
California and Georgia without (we hope) much of a problem. Now take the Mars Reconnaissance Orbiter.
Its X-band radio transmits at 100 watts, and we still need NASA’s (expensive) Deep Space Network to
pick the signal.
That’s why I’m excited to see projects like Lunar Flashlight and NEA Scout (mentioned above) get off
the ground — they are helping to roll the ball forward, and that’s also what we’re trying to do with

IAMA 022615 NL PSg PS A6 Q3 BudgetIAMA 022615 NL PSh PS A6 Q3 Budget


[–]Universu 3 points 4 hours ago
Could you compare planetary science funding for NASA in relation to ESA Roscosmos, JAXA ISRO and are
there missions most ideal for collaboration in today’s situation?

[–]CaseyDreierCasey Dreier – The Planetary Society[F,S] [score hidden] an hour ago
Generally, it’s much larger than all of those space agencies, and you can tell just by the number of
missions that NASA engages in compared to that of ESA/JAXA/ISRO/etc.
It’s actually quite difficult to do an apples-to-apples comparison of planetary science budgets
between NASA and other space agencies. ESA’s model is to pay for the bulk of the mission but have its
member countries’ space agencies chip in to pay for the rest. NASA’s model is completely different.
But it’s even difficult to compare funding year-to-year within NASA. This is basically due to changes
in internal accounting practices. For example, in 2014, NASA started paying for the Department of
Energy’s Plutonium-238/RTG infrastructure to the tune of about $50 million per year. In 2013,
Planetary got $1.28 billion. In 2014, Planetary ended up with $1.35 billion. That looks like an
increase of $70 million. But $50 million of that extra money isn’t paying for missions, it’s paying
for infrastructure previously supported by the DOE. So the real difference in $20 million. Multiply
that change by 20, and you begin to see the problem of comparing budgets.
Our Planetary Science Funding Chart attempts to do this over the past 10 years. We detail major
differences, but even then, we ignore many of the smaller ones because they’re very hard to track.
Since we only have access to public data, we don’t know exactly how much money every program gets
year to year, and NASA will often change how much detail it provides in its public budget.
A good example of this is the Orion crew capsule. NASA’s public budget request for 2016 call for
1.0858 billion dollars for Orion. This number is followed by eight pages of explanatory language
about the project, including contractors and potential risks. But there is no further breakdown of
that number that I know about.
The same budget requests $1.361 billion for planetary science, followed by fifty-three pages of
explanatory language, and breakdowns of spending on every major project, down to the costs of running
individuals missions, scientific research grants (most of them), and management costs.
And even if you get all the data, NASA often changes how they bookkeep a lot of funding in their
accounts. This makes it hard to know exactly where funding goes over the years. This is not a
coincidence (I should note that this happens for every federal agency, ever—this is not just NASA).
My colleague Jason Callahan has actually made a heroic effort to track planetary science funding (and
other science funding) in NASA over its 50-year history in a consistent way. You can check out his
series of posts about the rise and fall (and rise and fall) of planetary funding, called the
Competition for Dollars.

IAMA 022615 NL PSz2k A7 Q6 Shuttle To CCP


[–]Universu 2 points 10 hours ago
With Endeavor, Discovery and Atlantis being replaced by Orion, Dragon and CST, what will be the next
generation interstellar probes that can overtake the Voyagers?

[–]JasonCallahanJason Callahan – The Planetary Society[F] [score hidden] 3 hours ago
It’s difficult to compare the space shuttles to capsules, since the capabilities are so different.
The two types of craft are designed for very different missions. Dragon currently carries cargo to
the International Space Station like the shuttles once did, but it’s a much smaller vehicle. CST-100
(and a newer version of Dragon) is being developed to carry crew to ISS, but is probably closer to
the Soyuz capsule than the shuttle. Both CST-100 and the Dragon crew capsule will have far more
capability than Soyuz, though. Orion will carry fewer astronauts than the shuttles did, but will be
able to take them beyond low Earth orbit, which was the limit for all shuttle missions.
NASA has never launched an interstellar probe (unless you count space telescopes that peer beyond our
solar system without leaving it). Voyager 1 and 2 have (arguably) left our solar system and are the
first spacecraft to have done so, but they have not reached another star’s system and won’t for a
very, very long time. Pioneer 10 and 11 are also headed out of our solar system, but neither
spacecraft is still transmitting data. The New Horizons craft set to reach Pluto this summer will fly
past the dwarf planet (I still can’t get used to saying that) and may eventually leave the solar
system as well, I think.

We’re still taking questions about @NASA and space exploration: http://bit.ly/1LE3ltB

Planetary peeps: this would be a good opportunity to get thoughtful answers to FAQs you get from
friends and family.

Starting in 10 minutes: reddit AMA with @CaseyDreier @Bill_Adkins http://bit.ly/1Ft1Xb7

Now taking Qs on the #NASABudget:

IAMA 022615 NL PSa NL A1 Q1 Book


[–]Universu 2 points 5 hours ago
What is your favorite book?

[–]Nicole_Lapin[F,S] 2 points 5 hours ago
RICH BITCH – haha! And Anna Karenina has always been my favorite book – in fact, a line from Anna
Karenina is the origin of the name of my production company! And the book had a special meaning for
me because it was the place where I first wrote down my first long term goal-sheet. Like i wrote it
in the back of the book because I was so digi (like digital) that I only had a blackberry, iPhone,
iPad, so I just went to the back of the book and wrote down my goals for the very first time.

IAMA 022615 NL PSb NL A2 Q2 Book


[–]Universu 1 point 5 hours ago
What music do you listen to while writing?

[–]Nicole_Lapin[F,S] 2 points 5 hours ago
Rihanna. Or Katy Perry. Like, girl power music!

Join @NicoleLapin for her AMA live now:

Starting a @reddit_AMA!!! Join in!