People love to imagine alternative history, what could have happened if a certain battle
or political event went the other way.
Would the Nazis have won World War II?
Would there been a nuclear war over the Cuban Missile Crisis?
It's a fascinating concept, and I really enjoy this kind of speculation.
In fact, there's a great channel you should check out if you haven't already called
Alternate History Hub.
Lots of great space related alternate history as well as other topics.
Anyway, because I've been doing space journalism for so long, I've seen the creation and
then cancellation of many space-related projects and missions.
Some make sense, there was too much technological risk, the project was over budget, while others
seem a little short sighted.
In this episode, I wanted to take a look back at some projects and missions that were developed
to various stages and then cancelled.
What science could we have gotten from the mission?
What did we ultimately get?
It's the alternative history of astronomy and space exploration.
I'm going to present the three missions that I was most excited about, and the saddest
to lose.
If you listen to Astronomy Cast, you know, that podcast about space and astronomy that
I've been doing for 10 years with the astronomer Dr. Pamela Gay, where we cover topics in space
and astronomy, you'll know that my greatest sadness is the loss of the Terrestrial Planet
Finder.
The Kepler Space Telescope, which has already given us a treasure trove of planetary discoveries
was actually supposed to be the first part of a trilogy of space-based planetary observatories.
The second spacecraft in the series was called the Space Interferometry Mission, or SIM.
Unlike Kepler, which uses a single mirror, SIM was going to test the idea of interferometry,
where you combine the light from multiple mirrors into a single observation.
This idea is used successfully here on Earth, but it had never been tried in space (and
still hasn't).
You would think that by having two mirrors, your telescope would act like the combined
surface area of both.
But what actually happens is you get a resolution equal to the separation of the mirrors.
There are downsides, you can only see brighter objects, but the boost in resolution is very
useful.
In fact, this is why people talk about the powerful kinds of telescopes that could be
built if you put equal telescopes on opposite sides of the Solar System, for example.
It's as if you had a telescope with the resolution of the size of the Solar System.
Once launched, SIM would be the most powerful extrasolar planet ever launched, and it would
have have been capable of turning up Earth-sized worlds orbiting nearby Sun-like stars in the
habitable zone.
In other words, it would have found Earth 2.0.
But the third part of the trilogy is the one I miss the most: The Terrestrial Planet Finder,
cancelled in 2011.
This mission would have been built on the success of SIM to fly a formation of space
telescopes to act as a single large telescope.
It's job would be to help us discover planets, and more importantly, help us find out if
they have life on them.
The instrument would have used a coronagraph to block the light from stars to see the fainter
planets orbiting them in infrared light.
With hundreds of times the observing power of Hubble, the TPF would be able to measure
the composition of exoplanet atmospheres.
Find an atmosphere with ozone and it's a clear indication there's life present.
And if it could detect the air pollution from an advanced civilization, then we'd know
we're not alone in the Universe.
Although I'm sad to lose SIM and the Terrestrial Planet Finder, there's hope.
Astronomers are planning and building several new ground and space-based telescopes that
will have the same capability or even greater.
And if it ever gets built, the LUVOIR mission will put a 16-meter telescope into space.
That will change everything.
We'll talk more about the upcoming super telescopes in future episodes.
Now, it's time to go to Europa and look for life.
The search for life in the Solar System is all about the search for water.
That's because wherever we find liquid water here on Earth, we find life.
Is that true for other places than Earth?
We don't know.
One of the great discoveries from NASA's Voyager program was realization that three
of Jupiter's large moons: Europa, Ganymede and Callisto had a huge amount of liquid water,
kept warm by tidal interactions with Jupiter, and covered by a thick icy shell.
This sounded like the perfect place to go searching for life.
In 2004, Northrop Grumman began the development of a spacecraft with a range of revolutionary
capabilities called the Jupiter Icy Moons Orbiter, or JIMO.
Instead of a traditional chemical engine, this spacecraft would be equipped with 8 highly
efficient ion engines powered by a small nuclear fission reactor.
The reactor would have generated thousands of times the electricity of other spacecraft
power plants, which would power the engines.
With this configuration, JIMO would be capable of visiting each of Jupiter's icy moons.
Not just flybys, but it would be capable of going into orbit, examining each moon for
several months, and even deploying a lander for Europa.
If the mission had gone ahead, there would have been three separate launches in 2015
to low Earth orbit: two booster transfer stages, and then the actual probe.
The transfer stages would have kicked JIMO into the trajectory to reach Jupiter by 2021.
It would have arrived first at Callisto, studied it for three months, then switched to Ganymede
for three months, and finally arrived at Europa where it would have lived out its final days,
studying this intriguing world until 2025.
During this period, NASA was tasked with the Constellation Program, which shifted budgets
to human space exploration, and canceled several ambitious projects like JIMO.
This cancellation is even more sad now that we know there are active geysers on Europa,
and the food for bacterial life has been detected at Enceladus.
It would be the perfect time to have an enormous, nuclear powered mega probe orbiting the Jovian
System.
ESA and NASA partnered up with something called the Europa Jupiter System Mission, but this
was cancelled in 2011, and now ESA is building their own probe called the Jupiter Icy Moon
Explorer mission, or JUICE.
And NASA is working on its own mission called the Europa Clipper, which will visit the moon
in the 2020s.
Unfortunately, the lander portion of the mission was canceled earlier this year, so it'll
just be an orbiter.
It's better than nothing, though.
I've talked about two groups of missions that were canceled, and there's one more
to go.
But before I get to it, I'd like to thank Björn Poppe, David Gell, and the rest of
our 764 patrons for their generous support.
If you love what we're doing and want to get in on the action, head over to patreon.com/universetoday
Now I'm going to cross the ocean to Europe, and look at a cancelled program from the European
Space Agency: the Hermes spaceplane.
This was originally proposed in 1975 as an alternative to the much larger NASA space
shuttle.
Hermes would have only been capable of carrying 3 astronauts to orbit, but only a few tonnes
of cargo.
Which in retrospect was a pretty good idea, and is the direction NASA went after cancelling
the space shuttle.
The project officially began in 1985, investigating a 6-person spaceplane.
After the Challenger disaster, ESA wanted to give astronauts a chance to escape a disaster,
so it was decided it should have 3 ejection seats instead.
Hermes spaceplanes would have been carried to space atop Europe's new Ariane rockets,
and would be capable of 30 successive re-entries before they needed to be overhauled.
Each Hermes would have been capable of keeping a crew of 3 astronauts alive for 40 days,
with extended missions lasting 90 days.
It would have been capable of docking with various space stations, under human control
or autonomously.
Hermes was ultimately canceled in 1992, as ESA transferred its efforts into supporting
the International Space Station, and relying on the space shuttle to carry its astronauts
to orbit.
Although they never gained the ability to send humans to space, ESA is still pursuing
the space plane and lifting body concept.
As part of their Future Launchers Preparatory Program, ESA has been continuing to investigate
space planes.
In 2015, they launched the Intermediate eXperimental Vehicle, which was the first time a lifting
body ever made a re-entry from orbital velocity.
It had no wings, but flaps that could control its attitude.
It final landing was with parachutes in the Pacific Ocean.
For its next test, the IXV will try a runway landing.
If this works out, I'm sure we'll see more spacecraft based on this lifting body
concept as a way to return cargo and people from orbit, and even other worlds.
As I was working on this episode, I considered many more cancelled missions.
Let's take a moment to remember the X-33 which was an attempt to build a single stage
to orbit spacecraft.
The Constellation Program, which would have had humans set foot on the Moon again.
The Pluto Kuiper Express, which would have sent a probe to Pluto and Charon… okay,
New Horizons replaced it and did that.
There was the Comet Rendezvous and Flyby Mission, which would have sent a Cassini-class spacecraft
to a comet.
That was cancelled, but Rosetta accomplished most of its science goals.
For all the successful missions out there, many more were developed and then canceled.
Some because of budget problems or technological risk, and others because of a shift in the
political climate.
But what I've found time and time again is that specific goals to get achieved in the
end.
Even if a specific mission, instrument or spacecraft is canceled, the science goals
remain.
If it was worth doing, some version of it eventually does get done.
Although it sucks to see your favorite missions cancelled, it's all part of the process.
Were there any missions I missed?
Which canceled missions make you the saddest?
Which are you glad got cut?
Let me know your thoughts in the comments.
In our next episode, we look back fondly on the Voyager spacecraft, which are still going
after all these years.
They gave us our first look at the outer Solar System, and we still rely on their observations
to this day.
That's next time.
It's time for another playlist, all about the alternative history of space exploration.
I'm going to link you to a few interesting videos about what might have happened if things
had gone differently.
Starting with Alternate History Hub's take on what would happen if the Soviets landed
first on the Moon.
A Civilization 6 video about the Vikings colonizing space.
A video from Amy Shira Teitel about the cancelled Apollo missions.
What if NASA had the US military's budget.
And finally, an hour-long lecture from Neil DeGrasse Tyson at the 28th National Space
Symposium.
ESA and NASA partnered up called the - hmm hold on...
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