Guinness World Records 2018

FASTEST ATMOSPHERIC ENTRY

INTO EARTH’S ATMOSPHERE

On 15 Jan 2006, NASA’s Stardust sample return

capsule returned to Earth after a seven-year

mission to collect material from the comet Wild 2.

It entered the atmosphere travelling at a velocity

of 29,000 mph (46,660 km/h) and was visible in

some parts of the USA as a streak of light (above)

before touching down, by parachute, in Utah, USA.

SCI-TECH & ENGINEERING

A comet’s nucleus is one

of the darkest known

substances,

reflecting only

4% of light that

hits it. It is even

darker than the

blackest coal.

Seen

above is an

artist’s impression

of^ ESA’s^ Rosetta

spacecraft.^ It^ carried

the^

Philae lander, also shown

above, which separated

off^ to^ visit^ the^ comet

67P/Churyumov–

Gerasimenko

(see right).

Most distant observations of a comet
On 3 Sep 2003, astronomers at the European
Southern Observatory in Paranal, Chile, released
an image of Halley’s Comet at 4.2 billion km
(2.6 billion mi) from the Sun. It shows Halley as
a fuzzy dot with a brightness magnitude of 28.2,
nearly a billion times fainter than the faintest
objects visible with the naked eye.

First comet observed being
destroyed by the Sun
On 6 Jul 2011, NASA’s Solar Dynamics
Observatory took a series of images showing
Comet C/2011 N3’s last moments as it
disintegrated in the atmosphere of the Sun.
The comet, which had only been discovered
two days earlier, had an estimated nucleus size
of approximately 9–45 m (29–147 ft) across.
In its final seconds, Comet C/2011 N3 was a
mere 100,000 km (62,137 mi) from the Sun’s
surface and travelling at a velocity of around
2.1 million km/h (1.3 million mph) before it
broke up and was vaporized.

Most spacecraft to visit a comet

In 1986, Comet 1P/Halley entered the inner Solar

System as part of its 75–76-year elliptical orbit

around the Sun. Five spacecraft (collectively

nicknamed the “Halley Armada”) were sent to

encounter the comet as it approached perihelion

• the point at which it was closest to the Sun.
  Giotto (see opposite page) took the first close-
  up images of the comet’s nucleus, sustaining
  major damage from dust particles in the coma
  during its flyby. The Soviet Union sent Vega 1 and
  Vega 2 , both of which had deployed a lander and
  a balloon on Venus before proceeding to Halley.
  Japan sent Suisei and Sakigake, which came
  within 151,000 km (93,827 mi) and 6,990,000 km
  (4,343,384 mi) of the nucleus, respectively.

Most comets discovered by a spacecraft

The ESA/NASA spacecraft SOHO (Solar and

Heliospheric Observatory) was launched on

2 Dec 1995 to study the Sun from L1 – the

place between the Sun and Earth where the

gravities of the two bodies cancel each other

out. Its detection of comets has been purely

serendipitous but, as of 13 Sep 2015, SOHO

had discovered 3,000 of them.

Longest orbital survey of a comet

On  6  Aug 2014, ESA’s Rosetta spacecraft

entered orbit around comet 67P/Churyumov–

Gerasimenko. On 12 Nov 2014, it released

the lander Philae (see first image from the

surface of a comet, above). As the comet

was heading away from the Sun, the power

available to Rosetta’s solar panels decreased.

It was theoretically possible to put Rosetta

into hibernation and revive it once the comet

approached the Sun again. However, it was not

certain that the spacecraft would survive. Instead,

ESA opted to end the mission by impacting on the

comet’s surface, taking images and data until the

last possible moment. At 10:39 UTC (Coordinated

Universal Time) on 30 Sep 2016, Rosetta landed

in the Ma’at region of the surface, ending the

mission after 2 years 55 days of operations

at 6 7P/Churyumov–Gerasimenko.

FIRST IMAGE FROM THE SURFACE OF A COMET

ESA’s Philae lander touched down on the comet 67P/Churyumov–

Gerasimenko on 12 Nov 2014. Among its instruments was a set

of cameras known as the Comet Nucleus Infrared and Visible

Analyser (CIVA), designed to capture  360 ° panoramas of the

landing site. Shown above is the first image released, on 13 Nov

2014: a mosaic from two of the CIVA cameras, showing the cliff

face Philae landed next to and part of the lander itself.

The last contact with the Philae lander was on 9 Jul 2015, a

total of 239 days after its landing. That interval represents the

longest time survived on a comet by a spacecraft.

The word “comet”

comes from the

ancient Greek for

“hair of the head”

and was named

by Aristotle, who

described them as

“stars with hair”

According to one

biography, in 1456

Pope Callixtus III

believed Halley’s

Comet to be an agent

of the devil and had it

excommunicated

Edmond Halley suggested that the

biblical Noah’s flood could have been

caused by a comet colliding with Earth