I searched the Internet for
further details of the Nilesat 101 launch, hoping to find pictures of the
spacecraft that would help identify this piece of space
junk, but came up short. I finally received an e-mail
from a reader who knew exactly what it was. He
directed me to a series of websites that made it clear:
http://hea-www.harvard.edu/QEDT/jcm/space/images/lv/98024.html
http://www.multimania.com/europespace/ar4_v108.html
From the photos, it is clear
that we found the fairing (I previously referred to
it as a shroud) that covers the satellite spacecraft during
launch. The photo below (left) shows the fairing
covering the satellite as it is prepared for launch.
Note that there are two satellites stacked on top of each
other, Nilesat 101 is in the upper position, BSAT
1b is in the lower position. The photo below
(right) shows that same fairing as it lies today on the
beach in Bequia. Note that all the holes in the
fairing match up perfectly in both photos.
The photo below left shows
the logo being applied to the fairing in the preparation
phase in April 1998. The photo below right shows how
that logo survived the fall back to earth, floating in the
Atlantic Ocean before being beached.
The story of how satellites
are put into orbit is quite interesting. The launcher
(an Ariane 4 rocket) lifts off vertically (from
French Guyana) and after approximately five seconds banks
progressively towards the east to put it into geostationary
orbit. It takes about 2 minutes to reach a height of
around 60 km, at which point the two boosters separate and
fall into the sea.
The main stage burns for
about 12 minutes. During this time the launcher continues
its ascent in preparation for the horizontal trajectory
which is handled by the upper stage. As the launcher is
now above the Earth’s atmosphere the fairing, which
protected the satellites, is no longer needed and is
jettisoned. This occurs at the 3:40 mark.
It is during upper stage
burnout, which lasts approximately 13 minutes, that the
launcher reaches its highest velocity of around 8 km per
second. At this point the launcher’s upper stage
engine is cut and the computer on board the launcher
commands the satellites to spin on their axis. This
puts them into the correct position to continue by
themselves their journey into space.
The launcher is steered from
the ‘brain’ in the Vehicle Equipment Bay, placed above
the cryogenic main stage. Here, data is stored on
position, velocity and acceleration and the onboard
computers estimate in real-time the best trajectory and make
any necessary corrections.
Once the satellite or
satellites are on their way, the upper stage is sent into
what is called ‘cemetery orbit’ where it can do no
damage to other orbiting satellites and vehicles.
Nilesat 101 and BSAT 1b sit atop Ariane 44P
awaiting launch V108, April 28, 1998
The fairing now lies on the
eastern shore of Bequia, right beside the Old Hegg Turtle
Sanctuary, nestled into the brush that lines the
shore. I have sent an e-mail to the people at Nilesat
informing them of this, however I have yet to hear back from
them as of January 31, 2002. Just thought they might
be interested...
