# Will there be a last man on the moon?

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I was born in 1990. Mankind first stepped on the moon on July 20th 1969. We did it again in November of the same year, again in February and July of 1971, and in April and December of the following year.

In total there have been 12 men to have set foot on another celestial body. I have never known a day where I have not been sharing the Earth with a lunar astronaut. But today 8 of those 12 heroes have passed away. The 4 remaining, Buzz Aldrin, David Scott, Charles Duke and Harrison Schmitt are aged 89, 87, 83 and 84 respectively.

We haven’t been back to the moon since 1972. NASA have a target to get another human there with the Artemis mission by 2024, but is this already too late?

So my question to you is Is it likely that we will see another human on the moon before all our lunar astronauts go extinct? or will it soon be the day of the last man on the moon?

We can use statistics to help us infer the odds.

Firstly let’s take mortality predictions from the US social security actuarial life table of 2016.

Next we calculate the probability that an astronaut will die within n years, given their age. This is given by,

P(death in N years | current age) =
P(death in year N | age in year N) $\times$ P(alive in year N-1 | current age) + P(death in year N-1 | current age)

pdeadn = function(startyr = 2019, endyr = 2020, birthyr){
age = startyr - birthyr
nyrs = endyr-startyr+1 #add one because you count the first year as 2016
cat('number of years:', nyrs, '\n')

pdead[1] = data$pdeath_male[which(data$age == age)]
for(i in 2:nyrs){
age = age+1
pdead[i] = (1.0 - pdead[i - 1])*data$pdeath_male[which(data$age == age)] + pdead[i-1]
}

cat('final age:', age,'\n')
}

We apply this to our 4 alive astronauts, who were born in 1930, 1932, 1936 and 1935, to get the probability of their deaths up until 2040.

startyr = 2019 #start at current year since we know they are alive
endyr   = 2040
birthyr = c(1930, 1932, 1936, 1935)

Assuming that the deaths of any of the astronauts are independent events, the probability that all the lunar astronauts are dead is given by the multiplication rule,

P(all astronauts dead) = P(Aldrin dead) $\times$ P(Scott dead) $\times$ P(Duke dead) $\times$ P(Schmitt dead)

Applying this we can obtain the following plot of the probability that all astronauts are dead as a function of time,

yrs      = seq(2019, 2040)
plot(yrs, pdeadall, ty = 'l', tck = 0.02, xlab = 'year', ylab = 'P(all lunar astronauts dead)', xlim = c(2019, 2040))
axis(side = 3, tck = 0.02, labels = FALSE)
axis(side = 4, tck = 0.02, labels = FALSE)
abline(v = 2024, lty = 'dashed', col = 'orange', lwd = 3)

The orange line shows the goal launch date of NASA’s Artemis program to get the first woman and next man on the moon. From this we can see that there is a 12% probability that all the Apollo Astronauts will not see the next landing on the moon. However, experience shows that space launches are never delivered on time. The following plot shows the predicted launch date of NASA’s Hubble Space Telescope as a function of time.

Hubble launched in 1990, 2.3 times the original scheduled launch time. If the Artemis program faces similar delays, we won’t see a moon landing until 2031, by which case the probability that we will go back on progress, and that I will see a day where no man has stepped on the moon will have increased to 78%, and by 2034 (the set goal of the Chinese to land on the moon) almost certainly (93%) this will be the case 😦

# Have you got what it takes to be the next Cosmonaut?

Russian space agency ROSCOSMOS this week announced the opening of the next selection programme of cosmonauts (Russian astronaut) see: https://twitter.com/roscosmos/status/1135521818301870083

Don’t read Russian? No problem, I have you sorted:

You’re welcome! Applications are accepted from Russian citizens between now and 1 June 2020, and at the end of it there will be 4-6 newly selected Cosmonauts! Could that be you?

Interestingly they require a minimum footsize of 29.5cm… I wonder what that could be for?

Whilst here you know see the entry requirements for a Russian Astronaut, in my upcoming youtube video, I’ll be talking about what it takes it be an astronaut in general, so if you don’t follow my youtube channel yet, you really should!

# My city Coventry

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Okay so a few weeks ago at work a colleague asked me where I was from in the UK, and I replied
“Oh, it’s a small little town, you’ve probably never heard of it, Coventry. It’s close to Birmingham”.
This is a natural response for me given that I lived in the US for a year and the only city anyone had heard of is London.

Actually the worse conversation I ever had went something along the lines of:

Her: “You’re from England, wow you’re english is so good!”
Me *confused*: “Erm, yeh because English people tend to speak english… ”
Her: “Oh really, I thought you spoke french there”
Me: *facepalm*

Anyway. So it turned out that my colleague had indeed heard of coventry since there are at least 2 other ESA employees working here in Spain who are from Coventry.

Statistically wise this is a super amazing opportunity for me to calculate the probability of that actually happening!

So lets say there are ~400 employees at ESA, Spain.

Since employment is swayed by the contribution of ESA member states and the UK’s slice is ~8%, we expect there to be:

$0.08 \times 400 = 32$ employees at ESA from the UK.

The probability of selecting someone from coventry out of the whole of the UK is given by the ratio of their populations:

$\frac{\rm Coventry's\ population}{\rm UK\ population} = \frac{3.2\times 10^5}{6.6\times 10^7} = 0.005$

So we would expect

$0.005 \times 32 = 0.16$ employees from Coventry working at ESA spain!

Since we have at least 3 of them, the likelihood of us all being here is much smaller! Note also that we all come from all over Coventry and went to completely different schools, so its unlikely that there could be some sort of bias. None the less, good job Coventry on producing some great scientists!

# My review of the Martian – Beware of spoilers!

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Last night, I was invited to an expert panel screening of the Martian, complementary of The Odeon and the British Interplanetary Society.

Overall I really liked the movie. It is a feel good movie, with a great soundtrack. It is educational and the CGI of Mars was beautiful (in particular the dust devils!). Most importantly it is inspiring to the current generation of future Marstronauts. Mars is definitely a popular topic right now.

So I guess as a physics geek, let’s discuss the scientific flaws of the movie –

1. Mark Watney at the start of the movie gets bashed around by a horrific sand storm. In part this is true – Mars has global dust storms that engulf the entire planet. However dust storms on Mars are harmless due to its lack of atmosphere. It would feel like a light breeze.

2. In the movie the space transit vehicle Hermes has an awesome centrifuge to mimic gravity – in theory this could create an artificial gravity. In reality, a centrifuge with a small radius would have a diverse effects on the gravitational gradient. In other words, the gravity they feel at their head would be a lot stronger than what they feel at their feet. If you look at the graph below, you can see that the radius of the centrifuge would need to be of the order 1000 meters in order for the gravity to be consistent over a distance a few meters. This just isn’t feasible right now because of the cost to launch and the amount of energy required to power such a space craft.

Number of revolutions per minute as a function of radius of centrifuge required to create the same gravitational force we feel on Earth

3. When Mark Watney begins his Martian farm, he takes soil from the upper Martian surface. Bad idea! The soil on the surface is completely exposed to radiation and is riddled with perchlorates. Not only would this is would mean that the potatoes he grew are toxic, but even touching the soil wouldn’t be good for you! Watney would need to use soil about 5m below the surface to get similar radiation levels to that we have on Earth.

4. What’s more I doubt the potatoes would survive in such lack of light, Mars is 50% further away from the Sun compared to Earth so efficient LED lighting is crucial. On the topic of sunlight, the lack of solar panels was slightly worrying… if you compare to the ISS, it hosts 2500 sq meters of solar panels!

5. Water. There’s plenty of it on Mars, frozen in the soil. If you were to melt all the ice on Mars, there would be enough water to cover the entire surface. So it seems a bit silly that Watney didn’t just extract water from the soil.

Despite this, it’s not a scientific documentary so I don’t expect all the science to true but they do a relatively good job at it. I think the Martian was a great movie and I quite enjoyed it!

# Astronaut Andreas Mogensen

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Earlier this week I visited ESA’s European Astronaut Centre (EAC) in Cologne, Germany. I’ve been very fortunate for this to be the 3rd time I have been to facility. The last time was pretty cool – I mean, it’s not every day you get a personal tour by ESA astronaut Andreas Mogensen, especially whilst he’s preparing to go to space!

Well last week, Andreas Mogensen finally made his debut space flight to the international space station. For those of you who don’t know much about Andreas, here’s 5 facts that you really ought to know:

1. He was joined the European Astronaut Corps in 2009 and has been training for 6 years for his 10 day journey aboard the ISS

2. He is the 1st astronaut from Denmark and to celebrate the Danish company LEGO made 20 custom LEGO figurines to keep him company whilst in space. The LEGO toys will be prizes to kids that can come up with the best video of Andreas’ story

3. Originally his trip to the ISS was supposed to take 6 hours but instead it took 2 days to avoid space junk, that’s a long time to be stuck in the Soyuz – It’s a 5th the size of the shuttle orbiter!

4. When Andreas and fellow crew members boarded the ISS, they brought the total number of inhabitants up to 9. The ISS was only built for 6 astronauts!

5. His main task is of course science. These include testing a new water-cleaning system, hands-free goggles similar to google-glass, a tight-fitting suit that mimics the effects of gravity and controlling rovers on Earth to prepare for future missions on Mars.

At EAC, I was given the opportunity to sit in on a conference call with the ISS and space agencies from around the world. It was unbelievable that I was on a LIVE chat to all 9 astronauts in space! Space has never seemed more close than in that moment and it is a memory that I will cherish always. Follow Andreas’ journey on twitter @Astro_Andreas.

# 3 nights as an astronomer

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Welcome to Chile!

I had the rare opportunity to go observing on the 4m Blanco telescope on Cerro Tololo, Chile. The telescope itself was built in the 70’s so its mind blowing that it is still functional today. This telescope like many other similar oldies are constantly given new life with the instalments of new instruments. Right now, that would be DECam, a CCD imager who’s scientific purpose is to understand the cosmic acceleration.

I took the evening shuttle up mountain, with wild horses, goats and cacti of all shapes and sizes making appearances along the way. It is amazing the infrastructure they have in place here. The roads carved into the endless ripples of dry, desert hills. The journey took about 1.5hrs from the local town La Serena but would’ve taken a lot longer on donkey-back as they did back in the day. The facility on the mountain was impressive, it was fully equipped with internet, water and electricity and the meals were delicious. Every night whilst observing, the cooks would prepare us a night lunch – it was definitely needed. It’s currently winter in Chile which means the nights are long.

In between the hills you can clearly see the fog that is the inversion layer.

Evening twilight on Cerro Tololo, both observatories shown aren’t the ones I worked in but were just as impressive.

Just before night-fall, I would walk the path up to the observatory. The observatory is huge! i could actually see it, miles away whilst driving up the mountain. A shining orb of the knowledge to come, the dome is made of a reflective material in order to maintain the cool temperature within. At 7.30pm, I would head outside to watch the sunset. It was beautiful every time. The hills below were endless and engulfed within a hazy fog they call the inversion layer. If the inversion layer were not present, we would be able to see the south pacific ocean, however it would also mean bad weather to come. As the sunset, the snow-topped mountains would light up pink, twilight begins. Back in the control room we had to wait until the sun was 14 degrees below the horizon before we could begin. Once it did however, it was non-stop until 7.30am the next morning! Thankfully the observatory was fully equipped with a kitchen and toilets and the main thing was that it was warm!

Each night, I would take a break and go outside. It was always pitch black, which was quite worrying since I’m sure countless individuals have blindly stepped off the mountain to their deaths. The skies were unbelievably clear whilst I was observing, and it was easy to see the milky way. In deserted locations like these, where the light-polution from civilisation is non-existent, there are always countless more stars than the eye can see. Just before morning twilight, I observed for the first time the zodiacal light – a hazy glow in the east caused by scattered sunlight off interplanetary debris.

Dr Chris Lidman and I and the 4m Victor Blanco Telescope

For my observing run, I was accompanying Dr. Chris Lidman, a staff scientist of the Australian Astronomical Observatory (AAO). This gave me the opportunity to tour the telescope itself! Up 5 levels in an elevator is where the telescope lives. It was gigantic! In fact below the telescope there was a net to catch people in case they fell off! Mounted on the sides of the dome were 2 giant white screens that would be projected by LED lights for flat fielding. The floor below was the aluminizing chamber where every 2 years the mirror is dropped down and slid into. Here the old aluminium surface is removed using hydrochloric acid and a new aluminium layer is deposited. The whole process takes 6 days! The telescope is also regularly cleaned by CO2 and is carried out by walking onto the mirror itself! Another interesting thing I found was the cryogenic pump. This pump is used to maintain DECam’s temperature and is constantly roaring day and night. It kinda sounds like the Tardis. This amazing piece of equipment needs maintenance every 7 months, costs \$35,000 and will put the observatory out of use for a week.

I was lucky enough to get 3 clear nights of observing in total and am very sad to leave. However I really need to catch up on some sleep now. Adios Chile.

# Why on Earth would you want to go on a no return journey to Mars?

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Is this the money question? It certainly is the question that everyone wants to know!

Well, I could give an infinite list of the many reasons why we should go to Mars, but on a personal level, let me tell you why it is important for me.

Firstly you may think I am crazy – all scientists are in a way. But certainly I am not crazy enough to get me this far. I mean seriously, do you really think they would send a crazy person to space? Of course not.

I have always been obsessed with science and I owe it all to the great education system I was brought up on. The access to science club was really what inspired me to be a scientist. Ever since then I have wanted to be in the space industry that’s why I have a masters degree in space science and am currently doing a PhD in Astrophysics.

I currently research some of the most massive objects in the observable universe – galaxy clusters. It always blows my mind how insignificant we are. I will never be able to explore another galaxy cluster except through a telescope. We will never even leave our own galaxy in my lifetime since we have only just left the solar system with Voyager and that set off in 1977!!!

As a scientist all I want is to explore and learn. We can do this with a mission to Mars and at the same time we will inspire the next generation of scientists and generations to come. I want the public to be as much interested in the science we are capable of doing as I was as a child. What I am doing is going to change the world and make history.