Pathetic solar cells, cripple scientific missions

They could be doing some science right now. Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. They should have used plutonium as
the power source. In times passed they could load up probes will all
kinds of experiments, vastly increasing their utility and "bang for
the buck." Not now.

9 June 2011 Last updated at 08:11 ET
Rosetta comet chaser goes into deep sleep
By Jonathan Amos Science correspondent, BBC News

Europe's Rosetta spacecraft, which is heading for a rendezvous with a
comet in 2014, has been put into hibernation by its controllers.

The command was sent from Germany on Wednesday, instructing the probe
to enter a deep sleep. Only heaters and an "alarm clock" have been
left running.

Nothing will be heard from the spacecraft for the next two-and-a-half
years - not even a reassuring beep.

Rosetta should wake up at 1000 GMT on 20 January 2014.

Assuming it does, the spacecraft will then be just a few months away
from its appointment with Comet 67P/Churyumov-Gerasimenko out near the
Planet Jupiter.

The plan is for it to orbit the 4km-wide ball of ice and dust and put
a small lander on its surface.

"The spacecraft may now be at rest but the team has a busy time ahead,
getting ready for the meeting with the comet," said Dr Gerhard
Schwehm, the European Space Agency's (Esa) Rosetta mission manager.

"I expect I will be a little nervous on 20 January 2014, and I might
not sleep the night before - but I'll be really excited as well," he
told BBC News.

Remarkably, Rosetta caught sight of its quarry in recent weeks, even
though the object is still more than 150 million kilometres away. The
probe's onboard Osiris camera system, managed by scientists from the
Max Planck Institute for Solar System Research (MPS) in Germany,
succeeded in picking out the comet against a dense field of stars in
the Scorpius Constellation.

Rosetta's "bedtime" orders were despatched from Esoc, Esa's European
Space Operations Centre in Darmstadt.

The probe's scientific instruments had already been powered down in
recent months. The last instructions were to shut down sub-systems on
the satellite.

Rosetta was swivelled so that its solar wings faced the Sun, and it
was put in a gentle spin so that it no longer needed to use thrusters
to maintain a stable configuration.

The concluding message directing shut down was sent at 1258 GMT. It
would have taken 30 minutes for this message to reach Rosetta at its
great separation from Earth, and a few more minutes for the spacecraft
to act on the command. The Darmstadt controllers, who were using
listening stations in Australia, got confirmation that the satellite
was in full hibernation when it went silent at 1413 GMT.

The onboard computer has been left running to monitor two functions -
the clock system that will eventually wake Rosetta, and a pair of
heaters. These heaters will come on occasionally to ensure that the
entire satellite does not freeze up as it moves through the cold of
deep space.

"The thermal system is fundamental for the spacecraft to maintain all
the temperatures in a safe range for the instruments, for the units we
have onboard, and mainly for the propellant tanks," explained Esa
spacecraft operations manager Andrea Accomazzo.

"We cannot allow the propellant to freeze, otherwise in 2014, the
spacecraft will not be able to spin-down and recover from the
hibernation," he told BBC News.

The 31 months of sleep will see Rosetta fly an arc some 660 million km
from the Sun out to 790 million km and back. The probe is already the
most distant spacecraft to operate on solar power, but such is its
remoteness now that the solar panels are providing very little energy.
Putting the probe to sleep will draw minimum power.

Rosetta was launched back in 2004 and has taken a rather circuitous
route out to its comet target.

This has involved making a number of flybys of the inner planets,
using their gravity to pick up sufficient speed for the eventual comet
encounter.

It has already delivered some fascinating science, particularly at the
close passes it made to two asteroids - the rocks Steins, in 2008, and
Lutetia, in 2010.

When Rosetta wakes in the January of 2014, it will use the time before
its July rendezvous to study Churyumov-Gerasimenko and plan its
approach.

The intention is for Rosetta to follow the comet as it moves in
towards the Sun, monitoring the changes that take place on the body.

Comets - giant "dirty snowballs", as some have called them - are
believed to contain materials that have remained largely unchanged
since the formation of the Solar System 4.6bn years ago, and Rosetta
data should help researchers understand better how our local space
environment has evolved over that time.

"Rich" wrote in message
...
They could be doing some science right now. Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

On Jun 14, 4:18*pm, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

It could have been worse. They might have made Rich the pilot and
given him pedals to generate power and lose some weight in the
process!

Imagine him posting here at five minute intervals as he waited
(endlessly) for the comet to get close enough to enjoy a good day's
skiing.

No sleeping pills for Rich! We'd have every detail of his sorry
existence burnt into our memories by the time he reached his taxpayer
sponsored, skiing holiday resort.

Poor old Rich. He truly defines "human error." :-)

On Jun 14, 10:49*am, "Chris.B" wrote:
On Jun 14, 4:18*pm, "Giga2" "Giga2" just(removetheseandaddmatthe

wrote:

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

It could have been worse. They might have made Rich the pilot and
given him pedals to generate power and lose some weight in the
process!

Imagine him posting here at five minute intervals as he waited
(endlessly) for the comet to get close enough to enjoy a good day's
skiing.

No sleeping pills for Rich! We'd have every detail of his sorry
existence burnt into our memories by the time he reached his taxpayer
sponsored, skiing holiday resort.

Poor old Rich. He truly defines "human error." :-)

Loser leftist envirokooks like YOU are one of the reasons NASA is
rapidly becoming the laughing-stock of the space world.

On Jun 14, 6:30*pm, "$27 TRILLION to pay for Kyoto"
wrote:

Loser leftist envirokooks like YOU are one of the reasons NASA is
rapidly becoming the laughing-stock of the space world.

Ouch!

http://costofwar.com/en/

OUCH!

On Jun 14, 10:18*am, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:
"Rich" wrote in message

...

They could be doing some science right now. *Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. *They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

RTGs on US spacecraft have survived a couple of accidents without
releasing any radioactive material. The RTG on the Apollo 13 Lunar
Module survived re-entry at roughly 25,000 mph and is still intact on
the bottom of the Pacific.

RTGs that never left the Earth are another matter.

On Jun 14, 10:18*am, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:
"Rich" wrote in message

...

They could be doing some science right now. *Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. *They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

If a big rocket were to be launched on a path that took it directly
over your house any RTGs it might be carrying would be the least of
your concerns, in the event of an accident.

wrote in message
...
On Jun 14, 10:18 am, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:
"Rich" wrote in message

...

They could be doing some science right now. Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

RTGs on US spacecraft have survived a couple of accidents without
releasing any radioactive material. The RTG on the Apollo 13 Lunar
Module survived re-entry at roughly 25,000 mph and is still intact on
the bottom of the Pacific.

=Amazing! If true it must have been a very small unit. It is not listed in
specs here http://en.wikipedia.org/wiki/Lunar_M...Specifications


RTGs that never left the Earth are another matter.

wrote in message
...
On Jun 14, 10:18 am, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:
"Rich" wrote in message

...

They could be doing some science right now. Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

If a big rocket were to be launched on a path that took it directly
over your house any RTGs it might be carrying would be the least of
your concerns, in the event of an accident.

=Depends whether I was at home or not.

On Jun 15, 11:15*am, "Giga2" "Giga2" just(removetheseandaddmatthe
wrote:
wrote in message

...
On Jun 14, 10:18 am, "Giga2" "Giga2" just(removetheseandaddmatthe

wrote:
"Rich" wrote in message

...

They could be doing some science right now. Instead, they are in
hibernate mode because they used USELESS solar cells which don't
function well far from the sun. They should have used plutonium as
the power source.

Good power source for such a mission true. Not so good to put it on a big
rocket and fire it off over your house though.

RTGs on US spacecraft have survived a couple of accidents without
releasing any radioactive material. *The RTG on the Apollo 13 Lunar
Module survived re-entry at roughly 25,000 mph and is still intact on

the bottom of the Pacific.

=Amazing! If true it must have been a very small unit. It is not listed in
specs herehttp://en.wikipedia.org/wiki/Lunar_Module#Specifications

The RTG was part of the ALSEP. Solar panels would be useless during
the long lunar night.

RTGs that never left the Earth are another matter.