All About Space - UK (2020-02)

Since OSIRIS-REx arrived at Bennu, it’sspentthe
best part of a year surveying the asteroid,revealing
new mysteries and pinpointing the perfectlocation
to prop itself down to extract a surfacesample.On
12 December 2019 the OSIRIS-REx teamannounced
that the site for their sample collectionwillbea
region near the north pole, nicknamedNightingale.
“This is a day I’ve been dreaming of forovera
decade,” says Lauretta. “And it’s the culminationof
the work of hundreds of people workingthousands
of hours poring over the data that we’vereturned
from the asteroid over the past year.”
Nightingale was chosen ahead of theothersites

• Kingfisher, Osprey and Sandpiper –asitshowedit
  has lots of finely grained material, whichmakesit
  easy to collect. The region also has aloweralbedo,
  which could be an indication of the presenceof
  organic material.
  In other news, astronomers have beentrying
  to work out the mystery of the asteroidejecting
  particles into space. When the spacecraftfirst
  arrived, these particles could have beeneasily
  confused with stars in the background.However,
  after further investigation it was discoveredthat
  the asteroid is emitting material for someunknown
  reason. Three likely explanations arethatitisthe

resultofimpactswithmeteoroids,thermalstress

fracturingorthereleaseofwatervapour.

“AmongBennu’smanysurprises,theparticle

ejectionssparkedourcuriosity,andwe’vespent

thelastseveralmonthsinvestigatingthismystery,”

explainsLauretta.“Thisisa greatopportunityto

expandourknowledgeofhowasteroidsbehave.”

Theteamhavestatedthatanyofthesethree

explanationsareplausible,oritcouldevenbea

combinationofthem.Theyarealsohopingthata

sampleofthisemittedmaterialwillfinditsway

intothesamplingmechanismofOSIRIS-REx,

meaningthattherecouldbeananswerwaitingfor

themcome2023.

“ OSIRIS-REx really seeks to answer some

of the most fundamental questions that

we ask ourselves” DanteLauretta

To Bennu and back

ArrivalatBennu

ecember 2018

eapproachphasebeganinAugus

18,withabout 2 millionkilometre

.2millionmiles)separatingthetw

utthespacecraftdidn’tactually

rriveatBennuuntilDecember 201

A

D

T

0

b

ar

Launch from Earth

September 2016

OSIRIS-REx endured a successful

launch before beginning its two-year,

2-billion-kilometre (1.2-billion-mile)

journey through space to asteroid

Bennu, including a flyby of Earth.

Samplerehearsal

April 2020 – June 2020

riortothemainevent,the

pacecraftwillundergoatleasttwo

amplecollectionrehearsals.Itwill

eaveitsorbit,manoeuvreitself

boveitstargetandreturntoorbit.

sst

eess

S

A

P

sps

ssa

lle

a

Surveyingthesite

December 2018 – August 2019

OSIRIS-RExbegansurveyingthe

asteroid,brokendownintofour

differentphases:‘DuringPreliminary

Survey’,‘InOrbitalA’,‘InDetailed

Survey’and‘DuringOrbitalB’.

OSIRIS-REx

isequipped

withcameras,

spectrometers

anda

sophisticated

sample-

collecting

mechanical

arm

© United Launch Alliance

© NASA/ University of Arizona © NASA/ University of Arizona © NASA/ University of Arizona

The four sampling

sites on Bennu

These sites, named after birds

native to Egypt, were the four

candidates singled out to be

visited by OSIRIS-REx. But there

can only be one...

Sandpiper

Latitude:-47degrees

Longitude:^322 degrees

Thesouthernmostsiteisaflat

pieceoflandonthewallofa

largecrater,butappearsto

havehydratedminerals.This

couldhaverevealedpromising

detailsaboutunmodified

water-richmaterials.

© NASA