CCNet, 34/2003 -  25 March 2003

"Britain is planning its first solo space science mission in 20 years. Scientists hope to send a satellite into deep space to study solar influences on climate change. The Earthshine mission would showcase British expertise and provide vital data on climate change. Principal investigator Mike Lockwood believes going it alone will deliver answers more quickly than joining forces with other nations."
--Helen Briggs, BBC News Online, 24 March 2003

    BBC News Online, 24 March 2003

    Sky & Telescope, 20 March 2003

    The Jerusalem Post, 20 March 2003

    SpaceDaily, 23 March 2003

    Ottawa Citizen,  23 March 2003


>From BBC News Online, 24 March 2003

By Helen Briggs

Britain is planning its first solo space science mission in 20 years, BBC News Online has learned.
Scientists hope to send a satellite into deep space to study solar influences on climate change.

The Earthshine mission would showcase British expertise and provide vital data on climate change.

Principal investigator Mike Lockwood believes going it alone will deliver answers more quickly than joining forces with other nations.

"The need is to get the data quickly," he told BBC News Online. "Science has moved to a point where people are asking questions now that we can't answer because we don't have the data."

Maverick opinion

Earthshine strays into the contentious area of the Sun's influence on climate change.

Evidence suggests that variations in the amount of solar radiation reaching the Earth, because of changes in the Sun's activity, may impact on climate.

Most observers believe the solar contribution is minor compared with humanity's footprint on the planet but a few scientists argue that it may equal or outweigh human factors.

Dr Lockwood of the Rutherford Appleton Laboratory in Oxfordshire is keen to stress that he does not take the maverick view.

"I am not out to prove that anthropogenic effects are caused by the Sun," he said. "This (solar variability) is in no way a rival to manmade effects."

'Unique view'

The nature and extent of solar influence on climate is not fully understood, however, which is where Earthshine comes in.

The spacecraft would carry out experiments from a vantage point about 1.5 million kilometres from the Earth where there is an uninterrupted view of the Sun.

The spacecraft would have a "unique view" of the sunlight reflected back out to space by our planet, hence its name, Earthshine.

Its three scientific instruments would probe cosmic rays and clouds to test current models of climate change.

"The possibility that current climate models underestimate the effect of solar variations on climate is probably the single most contentious issue in climate research at the moment," said Dr Myles Allen of the department of physics at Oxford University.

"The mission has the potential to settle the argument or at least put an upper figure on how far the models are wrong."

Dr Lockwood estimates that Earthshine would cost about 16m, which he says is "absolutely tiny" for a space mission.

The Particle Physics and Astronomy Research Council, the Natural Environment Research Council and the Department of Trade and Industry are expected to provide funding. The satellite would be built by the space company, Astrium.

Copyright 2003, BBC


>From Sky & Telescope, 20 March 2003

By J. Kelly Beatty

March 20, 2003 | It's been 20 years since planetary scientists first realized that chunks of the Moon and Mars were practically falling into their laps as meteorites. And, while thankful for the free samples, they've always puzzled over why these two worlds are represented roughly equally on Earth. To date collectors have snatched up 24 distinct meteorites from the Moon (some of which were found in multiple pieces or paired with other finds) and 28 from Mars.
The puzzle arises because the lunar specimens should outnumber their Martian counterparts by more than 100 to 1. For one thing, the Moon's weaker gravity means that a much smaller impact will accelerate lunar debris to escape velocity, compared to the more energetic (and thus rarer) blasts necessary to eject something from Mars. Calculations performed several years ago by Brett Gladman (University of British Columbia) show that, once launched into space, a chunk of lunar rock has about a 50-50 chance of ending up on Earth - 10 times better odds than for an arrival from Mars.

So why aren't the meteorite-rich tracts of Antarctica and Saharan Africa littered with more chunks of Tycho and Mare Imbrium? The answer, according to James N. Head (Raytheon Missile Systems), may be that most of them have simply disappeared over the past 100,000 years or so, eroded to oblivion by wind and water. Head says that most meteorites from the Moon should reach Earth within only about 10,000 years, so if by chance there haven't been any recent lunar impacts, the arrival rate right now will be in a deep lull, and the old ones will be mostly gone.

Martian meteorites, by contrast, take an average of roughly 10 million years to make their way here, ensuring a steadier arrival rate. Long after the most recent wave of lunar rocks are eradicated by weathering, new messengers from Mars will keep trickling in - roughly once per month. Notably, four Martian falls have been witnessed firsthand, whereas no one has seen a piece of the Moon descending to Earth.

But there's a problem with this scenario. Head's scheme, which he presented yesterday at the annual Lunar and Planetary Science Conference, implies that all lunar meteorites should be recent arrivals, and that's not the case. Of the 13 with well-established travel times (determined by measuring their exposure to cosmic rays while in transit), six left the Moon between 500,000 and 9 million years ago. In fact, notes Kunihiko Nishizumi (University of California, Berkeley), lunar and Martian meteorites share the same basic age distribution.

Nonetheless, Head says, to date the census of the two groups is still "a wash," with 99 percent of the expected lunar meteorites somehow staying out of collectors' hands. Gladman agrees, noting that the near-equal numbers of lunar and martian meteorites "must be a consequence of the finite age of the [Antarctic] ice sheet combined with transfer dynamics that today deliver few meteorites from ancient lunar impacts, but a reasonable flux from larger ancient martian impacts."

Copyright 2003 Sky Publishing Corp.


>From The Jerusalem Post, 20 March 2003

About 65 million years ago, the collision of an asteroid about 10 kilometers in diameter with the Earth was apparently responsible for a thick layer of dust that killed off the dinosaurs, along with most life forms then in existence. Space researchers, including those at the Israel Space Agency (ISA), want to keep an eye on such cosmic vagabonds. The Israeli Knowledge Center on Celestial Bodies Threatening the Earth was established at Tel Aviv University recently. Dr. Noah Brosch, director of the university's Wise Observatory, serves as its director.

The ISA chose TAU and scientists from its academic staff to create and operate the national knowledge center on "Near Earth Objects" (NEOs) - space objects liable to collide with our planet and cause immense damage some day. The NEO center is a collaboration among the university's department of astronomy and astrophysics, the department of geophysics and planetary sciences, and the school of education.

Apart from the major planets, the solar system contains a population of small bodies called "minor planets" (asteroids) and comets. The International Astronomical Union collects information about more than 60,000 such bodies. Most of them orbit between Mars and Jupiter, while the comets reach father away. About 500 small bodies are known to approach rather close to Earth and, in rare cases, could collide with it. The danger of such impacts is now known to the scientists and to various governmental agencies. The US Congress charged the National Aeronautics and Space Administration with identifying 90% of such celestial bodies larger than one kilometer in diameter by 2008. Other countries initiated similar programs and now, with the establishment of the new knowledge center, Israel has joined the global effort.

The center's activities include observations from the Wise Observatory and others to detect new NEOs and follow-up known objects, as well as the organization of educational events for the general public. The first operational phase includes observations with the existing one-meter telescope. The second phase will see the introduction of an additional telescope to search for new asteroids and follow them automatically.

The members of the knowledge center encourage cooperative efforts with amateur astronomers and the education system. The center's work plan and NEOs will be discussed on April 13 from 9 a.m. at TAU's Lev Auditorium. The center operates a dedicated Web site at:

Copyright 2003, The Jerusalem Post


>From SpaceDaily, 23 March 2003

by Bruce Moomaw
Sacramento - Mar 23, 2003

"SpaceDaily" has now acquired additional information on the favored new mission plan for Europe's Rosetta comet-rendezvous spacecraft, whose planned January launch to comet Wirtanen had to be cancelled due to the disastrous failure of the immediately preceding launch of its Ariane 5 booster.

While a delayed launch to Wirtanen next January cannot be completely ruled out, the most probably replacement mission for the craft is a launch next February . Since this comet's nucleus is thought to be considerably bigger than Wirtanen's, this will require considerable replanning of the landing procedure for its small ejectable comet-nucleus lander (as described in SpaceDaily's March 20 article).

But simply getting to the comet also requires major redesign of its flight plan -- and part of this is trying to find new replacements for the two asteroids Rosetta was supposed to rapidly fly by for additional science observations during its circuitous 9-year trip to Wirtanen.

The first of those two asteroids was 4979 Otawara -- only a few kilometers wide, which may actually be a small chunk of the third-biggest asteroid Vesta broken loose by an ancient impact. (Vesta is the only big asteroid with actual flows of volcanic basalt on its surface; America's "Dawn" spacecraft is scheduled to visit it in 2010 and spend almost a year orbiting it for detailed study.)

The second would have been 140 Siwa -- a big "C-type" asteroid, thought to be made of the same darker "carbonaceous chondrite" rock that makes up most rocky bodies in the outer Solar System, which condensed out of the original solar-orbiting nebula out of which the Solar System formed at lower temperatures than the silicate rock bodies of the inner System, and so is much richer in water and even in organic compounds. (Siwa, at 110 km, would have been the biggest asteroid yet visited by a spacecraft.)

Those, however, are now out of reach. Rosetta's new flight plan calls for it to match orbits with comet Churyumov with an even more complex set of loops around the Sun than its original flight plan to Wirtanen did. It will still make a gravity-assist flyby of Mars -- but if the Feb. 2004 launch to Churyumov is chosen, it will also make three gravity-asist flybys of Earth instead of only two.

The new plan would involve Rosetta being initially launched into a near-Earth orbit with a period of exactly one year, allowing it to return to and fly by Earth at that time to get a boost into a more elongated orbit that will take it to Mars. (If it misses this launch window, it can be launched a year later directly from Earth to Mars -- but since Mars will be farther from the Sun in its mildly elliptical orbit than it would have been for a launch last January, such a direct flight to Mars will require a more powerful booster: either a Russian Proton, or the improved "Ariane 5 ECA" which failed so disastrously in December and might not be ready for this mission even by early 2005.)

However it gets to Mars, Rosetta will fly by that planet in Feb. 2007 (making some science observations as it does so) and getting a gravity-assist boost to further elongate its orbit. It will then return to Earth to make its second gravity-assist flyby of our home planet that November, putting itself into a still more elongated orbit with a period exactly two Earth years long -- so that it will return once again to make its third and last gravity-assist flyby of Earth in Nov. 2009, putting itself into a still more elongated orbit taking it almost as far from the Sun as Jupiter.

As it sails away from the Sun on that orbit, it will fire a burn on its main engine in mid-2011, moderately adjusting its path to help match orbits with Churyumov. Then -- three years later, as it starts to approach the Sun again -- it will close in on the comet's nucleus and carry out a months-long string of finer maneuvers to rendezvous with it after a total journey of about 10 1/2 years (two years longer than the originally planned flight).

Rosetta's planners have already carried out an extensive hunt for any asteroids it could fly past during this revised series of loops around the Sun, and have indeed found two. The first is 437 Rhodia, which it would fly past in Sept. 2008 at a speed of about 41,000 km/hour.

Rhodia -- only about 25 km wide -- may be a particularly unusual asteroid. It is thought to have an albedo higher than that of any other known asteroid, reflecting fully 56% of the light hitting it -- which would imply that it is made of some mineral as white as chalk (possibly a chance extrusion of some white rock like anorthosite, which formed on a bigger asteroid and was later broken loose by a collision).

The second asteroid target would be 21 Lutetia, a big asteroid about 100 km wide which Rosetta would fly past at about 55,000 km per hour in July 2010. While Lutetia is about the same size as Siwa, it is definitely odder -- it's one of the biggest of the so-called "M-class" asteroids, which until recently have been thought to be made largely of metallic nickel-iron alloy of the type that makes up many recovered meteorites.

M-class asteroids (tagged, like the other declared classes of asteroids, by the near-infrared spectra of their rocks as seen from Earth) are rather uncommon -- they make up only about 4 percent of asteroids. They have been thought to be pieces of the metal cores that formed at the centers of the dozen or so large "planetesimals", several hundred km wide, that orginally formed in the Asteroid Belt, before most of them were gradually shattered into smaller fragments by repeated collisions over the eons.

However, more detailed near-IR spectra recently show some signs that most of the bigger M-class asteroids -- including Lutetia -- may not be metallic at all. Instead, they may be made of silicate rocks that were exposed to some water during their early history. Many of the smaller M asteroids -- as well as 16 Psyche, the biggest of all -- don't seem to show such evidence, and may be the real thing. If Rosetta does visit Lutetia, its color photos, close-up IR spectra and magnetic field measurements will likely settle this question.

There, is, however, a catch. Matching orbits with Churyumov will require more maneuvering fuel than Wirtanen would have. And so, in order to take the orbital paths needed to intercept the asteroids, Rosetta would have to rendezvous with its main comet target when the comet is closer to the Sun than Wirtanen would have been -- only 540 million km from the Sun, as opposed to the 600 million km planned for Wirtanen.

Since, as a comet approaches the Sun, the "coma" of gas and dust boiling off it dramatically increases, as Churyumov reaches its perihelion it will get much harder for the comet-orbiting spacecraft and its lander to make their observations. (Rosetta's design specifications only guarantee its full operation beyond doubt until the comet approaches within 490 million km of the Sun.) Scientists therefore would very much like to rendezvous with the comet when it's still 600 million km from the Sun as originally planned, to prolong their detailed observation time there. They will thus have to decide which they prefer: those two asteroid flybys, or as much as six extra months of time studying Churyumov itself in detail.

They have plenty of time to make that decision, however -- it can actually delayed until after launch. At any rate, given the initial alarming indications immediately after the cancellation of last January's launch that they might be able to find a workable replacement target for Rosetta at all, ESA scientists are quite happy even to have such a choice.

Copyright 2003, SpaceDaily

>From Ottawa Citizen, 23 March 2003

The Complete Idiot's Guide to Surviving Anything
By Patrick Sauer and Michael Zimmerman

"Some situations demand more than sensible shoes, a first-aid kit and the rules Mom taught you," say the authors of this survival manual. This guide includes tips for all kinds of situations from avoiding asteroids to battling bears. Notes survival expert Gregory Davenport in a Foreword: "The will to survive is the most influential factor in staying alive."

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