Why the Closest Planet Is the Hardest to Visit

Now, Mercury is the planet that's usually closest to Earth, because that surprised you,

did me.

Venus certainly gets closer to us than Mercury.

It can be as close as 25 million miles.

After all, Venus is the second planet from the Sun, and Earth is the third.

Even Mars gets closer to Earth than Mercury.

The red planet can come as close to our home as 35 million miles, as it will in the year

2287.

I won't be around for that.

The average distance from Earth to Mercury is 48 million miles, but Mercury is still

usually the closest planet to Earth.

That's because Venus is usually somewhere on the other side of the Sun for 112 days,

and Mars is usually far away in its highly elliptical, almost two-year-long orbit.

That leaves Mercury zipping between the Earth and the Sun every 44 days, and does

us usually closer to Earth than either Venus or Mars.

A good trivia question to pull on your friends, isn't it?

22 spacecraft have successfully flown to Venus, and over 30 spacecraft have flown to Mars,

but only two have ever gone to Mercury.

So what's so hard about going there?

Well, it has to do with the Sun.

Mercury is not only the planet that is usually closest to Earth, it is also the planet that

is always closest to the Sun, 28.6 million miles close to be precise.

Being that close to the Sun creates navigational challenges to put it mildly.

Any spacecraft going to Mercury gets accelerated by the tremendous gravitational pull of the

Sun.

The spacecraft will be moving too fast to go into orbit around Mercury.

That's why the first spacecraft that went to Mercury, the USA's Mariner 10 merely flew

by Mercury three times, but made no attempt to achieve orbit around Mercury.

The only other ship to go to Mercury, the USA's messenger spacecraft, took six and a half

years to get there.

Now that's a trip.

Messenger did achieve orbit for a period of four years before it's tax season, and at

life-lock, we know you're tired of numbers, but here's a big one you need to hear.

Billions.

That's the amount of money and refunds the IRS has flagged for possible identity fraud.

Now here's another big number, 100 million.

That's how many data points life-lock monitors every second.

If your identity is stolen, we'll fix it guaranteed.

One last big number, save up to 40 percent your first year.

Visit lifelock.com slash podcast for the threats you can't control.

Terms apply.

For finally running out of fuel and crashing onto the surface of Mercury on April 20, 2015.

The other spacecraft have flown to Jupiter in about the same time or less than it took

messenger to go to Mercury.

The hang-up is the deceleration of the spacecraft.

Quite simply, it takes too much on-board fuel supply to fire the engines in the reverse direction

and break the speed of the ship against the sun's great gravity.

Slowing down sufficiently to get into orbit around Mercury is a no-go using rocket power.

Some other way had to be found to slow messenger down, a way that didn't use much or any fuel.

Messenger was a hefty 2,400 pounds or so, loaded with 9 pieces of state-of-the-art scientific

equipment.

Now, 55 percent of the total weight, or about 1,300 pounds, was fuel.

But this fuel would not be used to slow the spacecraft down.

The fuel would be used for five engine burns associated with gravity assists and also

for orbital adjustments once messenger got to Mercury.

Now, gravity assists uses the gravity of a planet and the planet's orbital velocity

to either speed up or slow down a spacecraft.

If the ship approaches a planet at a forward-moving angle, that is, an angle in the direction

the planet is revolving around the sun, then both the planet's gravity and the orbital

velocity of the planet give the spacecraft a sling shot boost, greatly increasing the

speed of the craft and sending it off in a different direction.

This boost in speed can be added to by the spacecraft firing its rocket engines at just

the right time.

Both of America's Voyager probes use Jupiter's massive gravity to sling shot them to the

outer-gas giant planets and eventually out of the solar system.

Gravity assists can also be used to slow down a spacecraft, as in the case of messenger.

By entering a planet's orbital path ahead of the planet, the planet's gravity pulls back

on the spacecraft and slows it down.

An engine burn is necessary at this time to escape the orbital path of the planet.

Messenger performed one gravity assist flyby of Earth, two gravity assist flybys of Venus,

and three gravity flybys of Mercury.

He then had messenger been slowed enough to enter into orbit around Mercury.

The probe traveled an astounding five billion miles to get to Mercury from Earth, that's

farther than Pluto is away from Earth at its most distant.

The name messenger is an acronym, almost as clever as its intricate flight path to Mercury.

Because Mercury is the fastest moving planet, the ancient Greeks appointed Mercury as

the messenger of Olympus.

Venus traveled fast even back then.

Messenger really stands for Mercury Surface Space Environment Geochemistry and Ranging.

Hmm, what do you think?

Do they have a contest to come up with that?

Now, the good news is, there's another mission to Mercury underway right now.

It is a combined ESSA-JAXA space mission that is bringing two orbiting satellites to Mercury.

The mission doesn't use an acronym for its spacecraft, it has a real name.

Beppy Colombo.

No, it's not a cartoon character.

Dr. Giuseppe Colombo, after whom the spacecraft is named, was an Italian mathematician and

professor of applied mechanics.

He worked with NASA on the Mariner 10 mission to Mercury.

Beppy is Giuseppe's childhood nickname, which everyone knew and loved him.

XMA is unpredictable, but you can flare less with eggless, a once-monthly treatment for

moderate-disappear XMA.

After an initial four-month or longer dosing phase, about four and ten people taking eggless,

achieved itch relief and glare are almost glare skin at 16 weeks, and most of those people

maintain skin that's still more glare at one year with monthly dosing.

EMPGLIS, library kizumap, LBKZ, a 250-milligram per 2-milliliter injection is a prescription medicine

used to treat adults and children 12 years of age and older who weigh at least 88 pounds

or 40 kilograms with moderate-disappear XMA.

Also called a topic dermatitis that is not well controlled with prescription therapies

used on the skin, or topicals, or who cannot use topical therapies.

EMPGLIS can be used with or without topical corticosteroids.

Don't use if you're allergic to EMPGLIS.

A allergic reaction can occur that can be severe.

Eye problems can occur.

Tell your doctor if you have new or worsening eye problems.

You should not receive a live vaccine when treated with EMPGLIS.

Before starting EMPGLIS, tell your doctor if you have a parasitic infection.

Ask a doctor about EMPGLIS and visit EMPGLIS.lily.com or call 1-800-LilyRX or 1-105-4-5-9-7-9.

Bye.

NASA had been content with one flyby of Mercury, the first ever.

Professor Beppi calculated that with a slight adjustment of the flight path to enable a gravity

assist at Venus, Mariner-10 could fly by Mercury again and again on different orbits around

the Sun.

Thanks to Beppi, NASA got three flybys of Mercury for the price of one.

Beppi Columbo, though spacecraft, is scheduled to perform nine gravity assist flybys, one

at Earth, two at Venus, and six at Mercury itself.

Such planetary deceleration slows Beppi Columbo relative to the speed Mercury is moving around

the Sun.

This will allow for orbital insertion, otherwise Beppi Columbo would head off into the Sun.

Now, once an orbit around Mercury, Beppi Columbo's Mercury Transfer Module or MTM for

short will release two satellites, one European, the MPO, Mercury Planetary Orbiter, and

one Japanese, the MiO, Mercury Magnetospheric Orbiter.

Both are expected to orbit Mercury for one year.

Altogether, the MCS, Mercury Composite spacecraft, consists of the MPO, the MiO, the MTM,

and MOSF, which protects the spacecraft from the Sun and houses the electronics for MiO.

This alphabet soup of mission components highlights the other reason it is difficult

to get to Mercury.

Under six gravity assist slowdowns, six engine burns, 18 orbits around the Sun, six and

a half years of travel time, and nine billion miles of distance.

You have to bring a tailored complex of equipment.

It's like that mountain picnic you'd like to go on.

You can't just drive there.

You have to hike a long way up a tricky mountain trail and bring along insect repelling, sunscreen,

and your head.

Oh, and lunch and beverages, it's not easy.

Tipo Colombo has packed it all, including lunch.

Nah, not really.

The design is incredibly complex.

Nothing can face the Sun, not even the solar panels.

The solar panels must be kept turned almost to a right angle to the Sun, or the heat and

particle flux will corrode the solar cells, and without electricity, you have nothing.

Therefore, at right angles to the Sun, the solar panels must be extra long, as if there

were only a little bit of sunshine.

Beppie's solar panels are 50 feet long.

The Sun shield must remain gyroscopically aligned towards the Sun, so that all instruments

are always in the shade, but still have a line of sight to what each is meant to monitor.

And there are a lot of instruments.

Five in the Jackson Orbiter, and eleven in the Esa Orbiter.

It's one amazing picnic.

Anyway, the science objectives are meant to add to what we have learned from the previous

two missions to Mercury.

The data collected by Beppie Colombo will enable scientists to study the planet's interior

and composition, along with Mercury's geology and surface morphology.

Mercury's magnetic fields formation and evolutionary history, the planet's solar wind interactions

and overall environment.

As a middle-rich planet, Mercury may hold a vast wealth of minerals that messenger

fail to detect.

Beppie Colombo launched in October 2018 and still has a long way to go before he goes

into orbit around Mercury.

However, Beppie has already flown past Mercury and returned new photographs.

The European Space Agency is excited about its first hot mission.

All of the Esa's previous missions have been cold missions to objects further out into

space, such as Mars, the asteroid belt, comet rendezvous, and elsewhere far out in

the solar system.

Well, all I can say is, best wishes to Beppie Colombo.

Let's hope all goes well on its 800 degrees Fahrenheit mission to Mercury.

Let's hope that Mercury's long tail of exosphere gases, sodium, magnesium, and potassium, blown

off the planet's surface by the solar wind, don't fog up the lenses or coat the solar panels.

Have a nice time, ciao, baby!

This episode is brought to you by Athletic Brewing Company.

No matter how you do game day, on the couch, in the crowd, or manning the snack table,

Athletic Brewing fits right in.

With a full lineup of non-alcoholic beer styles, you can enjoy bold flavors all game-long.

No hangovers, no buzz, no subbing out for water in the second half.

Stuck the fridge for tip-off with a variety of non-alcoholic craft styles available at

your local grocery store or online at AthleticBruing.com.

Near beer, fit for all times.

President Barack Obama.

Virginia, we are counting on you.

Republicans want to steal enough seats in Congress to raid the next election and wield unchecked

power for two more years, but you can stop them by voting yes by April 21st.

Help put our elections back on a level playing field and let voters decide not politicians.

Vote yes by April 21st.

Paid for by Virginians for fair elections.